WorldWideScience

Sample records for temperate conifer forests

  1. Exotic ecosystems: where root disease is not a beneficial component of temperate conifer forests

    Science.gov (United States)

    William J. Otrosina

    2003-01-01

    Forest tree species and ecosystems ahve evolved under climatic, geological, and biological forces over eons of time. The present flora represents the sum of these selective forces that have acted upon ancestral and modern species. Adaptations to climatic factors, soils, insects, diseases, and a host of disturbance events, operating at a variety of scales, ahve forged...

  2. Life strategies in intra-annual dynamics of wood formation: example of three conifer species in a temperate forest in north-east France.

    Science.gov (United States)

    Cuny, Henri E; Rathgeber, Cyrille B K; Lebourgeois, François; Fortin, Mathieu; Fournier, Meriem

    2012-05-01

    We investigated whether timing and rate of growth are related to the life strategies and fitness of three conifer species. Intra-annual dynamics of wood formation, shoot elongation and needle phenology were monitored over 3 years in five Norway spruces (Picea abies (L.) Karst.), five Scots pines (Pinus sylvestris L.) and five silver firs (Abies alba Mill.) grown intermixed. For the three species, the growing season (delimited by cambial activity onset and cessation) lasted about 4 months, while the whole process of wood formation lasted 5-6 months. Needle unfolding and shoot elongation followed the onset of cambial activity and lasted only one-third of the season. Pines exhibited an 'extensive strategy' of cambial activity, with long durations but low growth rates, while firs and spruces adopted an 'intensive strategy' with shorter durations but higher growth rates. We estimated that about 75% of the annual radial increment variability was attributable to the rate of cell production, and only 25% to its duration. Cambial activity rates culminated at the same time for the three species, whereas shoot elongation reached its maximal rate earlier in pines. Results show that species-specific life strategies are recognizable through functional traits of intra-annual growth dynamics. The opposition between Scots pine extensive strategy and silver fir and Norway spruce intensive strategy supports the theory that pioneer species are greater resource expenders and develop riskier life strategies to capture resources, while shade-tolerant species utilize resources more efficiently and develop safer life strategies. Despite different strategies, synchronicity of the maximal rates of cambial activity suggests a strong functional convergence between co-existing conifer species, resulting in head-on competition for resources.

  3. Management strategies for bark beetles in conifer forests

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    Christopher Fettig; Jacek  Hilszczański

    2015-01-01

    Several species of bark beetles (Coleoptera: Curculionidae, Scolytinae) are capable of causing significant amounts of tree mortality in conifer forests throughout much of the world.  In most cases, these events are part of the ecology of conifer forests and positively influence many ecological processes, but the economic and social implications can be...

  4. Optimal nitrogen fertilization of boreal conifer forest

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    Timo Pukkala

    2017-03-01

    Full Text Available Background Forest fertilization offers a means to increase the production of renewable resources. Nitrogen is the most common fertilizer in boreal upland forests. There is plenty of research on the effect of nitrogen fertilization on volume growth, but less research on the optimal timing of fertilization and optimal management of fertilized stands. Methods This study used simulation and optimization to analyze the profitability of fertilization, optimal management of fertilized stands and the effects of fertilization on cash flows and timber yields. The management of 100 stands representing the most common growing sites of Scots pine and Norway spruce was optimized. Results Fertilization improved profitability in most of the analyzed stands. Profitability improved most in spruce stands growing on mesic site. Improving stem quality increased the economic benefit of fertilization. The timber yields of medium-aged conifer stands can be increased by almost 1 m3ha-1a-1 (15% in sub-xeric pine and mesic spruce sites and about 0.5 m3ha-1a-1 (5% in mesic pine and herb-rich spruce sites when the recommended nitrogen dose (150 kg ha-1 is applied once in 30 years. Conclusions Nitrogen fertilization of boreal conifer forest should be used mainly in spruce-dominated stands growing on medium sites. The gains are the highest in stands where the mean tree diameter is 16–20 cm and stand basal area is 14–20 m2ha-1.

  5. Mixed-Severity Fire Fosters Heterogeneous Spatial Patterns of Conifer Regeneration in a Dry Conifer Forest

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    Sparkle L. Malone

    2018-01-01

    Full Text Available We examined spatial patterns of post-fire regenerating conifers in a Colorado, USA, dry conifer forest 11–12 years following the reintroduction of mixed-severity fire. We mapped and measured all post-fire regenerating conifers, as well as all other post-fire regenerating trees and all residual (i.e., surviving trees, in three 4-ha plots following the 2002 Hayman Fire. Residual tree density ranged from 167 to 197 trees ha−1 (TPH, and these trees were clustered at distances up to 30 m. Post-fire regenerating conifers, which ranged in density from 241 to 1036 TPH, were also clustered at distances up to at least 30 m. Moreover, residual tree locations drove post-fire regenerating conifer locations, with the two showing a pattern of repulsion. Topography and post-fire sprouting tree species locations further drove post-fire conifer regeneration locations. These results provide a foundation for anticipating how the reintroduction of mixed-severity fire may affect long-term forest structure, and also yield insights into how historical mixed-severity fire may have regulated the spatially heterogeneous conditions commonly described for pre-settlement dry conifer forests of Colorado and elsewhere.

  6. Cold in the common garden: comparative low-temperature tolerance of boreal and temperate conifer foliage

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    G. Richard Strimbeck; Trygve D. Kjellsen; Paul G. Schaberg; Paula F. Murakami

    2007-01-01

    Because they maintain green foliage throughout the winter season, evergreen conifers may face special physiological challenges in a warming world. We assessed the midwinter low-temperature (LT) tolerance of foliage from eight temperate and boreal species in each of the genera Abies, Picea, and Pinus growing in an arboretum in...

  7. Leaf life spans of some conifers of the temperate forests of South America Longevidad foliar de algunas coníferas de los bosques templados de Sudamérica

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    CHRISTOPHER H. LUSK

    2001-09-01

    Full Text Available Interspecific variation in leaf life span has wide-ranging implications for plant species sorting on resource availability gradients, and for ecosystem processes such as nutrient cycling. Very little is known about leaf life spans of evergreen trees in the temperate forests of South America. Leaf life spans were estimated by static demographic methods, and associated leaf traits measured, for four conifers of this region. It was expected that leaf life span variation would correlate negatively with soil fertility of habitats normally occupied by each species. This prediction was upheld by the data. The mean leaf life span determined for Araucaria araucana (24 years is among the highest figures reported for any plant species. This extreme leaf longevity was associated with very robust construction (high leaf mass per unit area and very low nitrogen content. These aspects of the ecology of A. araucana may affect its fitness in two ways. Firstly, slow foliage turnover will reduce its annual nutrient requirements for crown maintenance, a trait that is thought to be crucial for survival on nutrient-poor sites. Secondly, the low decomposability of A. araucana leaf litter is likely to cause nutrient immobilisation, possibly favouring site retention by A. araucana in the face of competition from faster-growing but more nutrient-demanding species. Interspecific variation in leaf life span appeared to be systematically related to variation in leaf mass per unit area (LMA and leaf nitrogen, in agreement with a large body of evidence that leaf evolution is constrained by a trade-off between trait combinations which optimise carbon gain and growth in resource-rich habitats, and those which favour persistence in chronically adverse environmentsLas diferencias específicas en longevidad foliar tienen importantes implicancias para la distribución de las plantas en relación con gradientes de recursos, y en procesos ecosistémicos tales como el ciclaje de

  8. Influence of elevation and site productivity on conifer distributions across Alaskan temperate rainforests

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    John P. Caouette; Ashley E. Steel; Paul E. Hennon; Pat G. Cunningham; Cathy A. Pohl; Barbara A. Schrader

    2016-01-01

    We investigated the influence of landscape factors on the distribution and life stage stability of coastal tree species near the northern limit of their ranges. Using data from 1465 forest inventory plots, we estimated probability of occurrence and basal area of six common conifer species across three broad latitudinal regions of coastal Alaska. By also comparing...

  9. Dynamics of low-temperature acclimation in temperate and boreal conifer foliage in a mild winter climate

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    G. Richard Strimbeck; Trygve D. Kjellsen; Paul G. Schaberg; Paula F. Murakami

    2008-01-01

    To provide baseline data for physiological studies of extreme low-temperature (LT) tolerance in boreal conifers, we profiled LT stress responses, liquid nitrogen (LN2)-quench tolerance, and sugar concentrations in foliage of boreal-temperate species pairs in the genera Abies, Picea and Pinus, growing in an...

  10. Tree mortality in drought-stressed mixed-conifer and ponderosa pine forests, Arizona, USA

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    Joseph L. Ganey; Scott C. Vojta

    2011-01-01

    We monitored tree mortality in northern Arizona (USA) mixed-conifer and ponderosa pine (Pinus ponderosa Dougl. ex Laws) forests from 1997 to 2007, a period of severe drought in this area. Mortality was pervasive, occurring on 100 and 98% of 53 mixed-conifer and 60 ponderosa pine plots (1-ha each), respectively. Most mortality was attributable to a suite of forest...

  11. Vegetation and Ecological Characteristics of Mixed-Conifer and Red Fir Forests at the Teakettle Experimental Forest

    Science.gov (United States)

    Malcolm North; Brian Oakley; Jiquan Chen; Heather Erickson; Andrew Gray; Antonio Izzo; Dale Johnson; Siyan Ma; Jim Marra; Marc Meyer; Kathryn Purcell; Tom Rambo; Dave Rizzo; Brent Roath; Tim. Schowalter

    2002-01-01

    Detailed analysis of mixed-conifer and red fir forests were made from extensive, large vegetation sampling, systematically conducted throughout the Teakettle Experimental Forest. Mixed conifer is characterized by distinct patch conditions of closed-canopy tree clusters, persistent gaps and shrub thickets. This heterogeneous spatial structure provides contrasting...

  12. Tree communities of lowland warm-temperate old-growth and neighboring shelterbelt forests in the Shikoku region of southwestern Japan

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    Shigeo Kuramoto; Shigenori Oshioka; Takahisa Hirayama; Kaori Sato; Yasumasa Hirata

    2007-01-01

    We characterized the tree species composition of a 30 ha old-growth and neighboring shelterbelt (reserved buffer strips among conifer plantations) in warm-temperate forests in the Shikoku region of southwestern Japan. Using a two-way indicator species analysis of data from 28 plots, we identified four structural groups in terms of relative basal area. These structural...

  13. Use of waveform lidar and hyperspectral sensors to assess selected spatial and structural patterns associated with recent and repeat disturbance and the abundance of sugar maple (Acer saccharum Marsh.) in a temperate mixed hardwood and conifer forest

    Science.gov (United States)

    Anderson, J.E.; Ducey, Mark J.; Fast, A.; Martin, M.E.; Lepine, L.; Smith, M.-L.; Lee, T.D.; Dubayah, R.O.; Hofton, M.A.; Hyde, P.; Peterson, Birgit; Blair, J.B.

    2011-01-01

    Waveform lidar imagery was acquired on September 26, 1999 over the Bartlett Experimental Forest (BEF) in New Hampshire (USA) using NASA's Laser Vegetation Imaging Sensor (LVIS). This flight occurred 20 months after an ice storm damaged millions of hectares of forestland in northeastern North America. Lidar measurements of the amplitude and intensity of ground energy returns appeared to readily detect areas of moderate to severe ice storm damage associated with the worst damage. Southern through eastern aspects on side slopes were particularly susceptible to higher levels of damage, in large part overlapping tracts of forest that had suffered the highest levels of wind damage from the 1938 hurricane and containing the highest levels of sugar maple basal area and biomass. The levels of sugar maple abundance were determined through analysis of the 1997 Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) high resolution spectral imagery and inventory of USFS Northern Research Station field plots. We found a relationship between field measurements of stem volume losses and the LVIS metric of mean canopy height (r2 = 0.66; root mean square errors = 5.7 m3/ha, p < 0.0001) in areas that had been subjected to moderate-to-severe ice storm damage, accurately documenting the short-term outcome of a single disturbance event.

  14. Moist temperate forest butterflies of western Bhutan

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    Arun P. Singh

    2016-03-01

    Full Text Available Random surveys were carried out in moist temperate forests (1,860–3,116 m around Bunakha Village and Dochula Pass, near Thimphu in western Bhutan, recording 65 species of butterflies.  Of these, 11 species, viz., Straightwing Blue Orthomiella pontis pontis Elwes, Slate Royal Maneca bhotea bhotea Moore, Dull Green Hairstreak Esakiozephyrus icana Moore, Yellow Woodbrown Lethe nicetas Hewitson, Small Silverfork Zophoessa jalaurida elwesi Moore, Scarce Labyrinth, Neope pulahina (Evans, Chumbi Wall Chonala masoni Elwes, Pale Hockeystick Sailer Neptis manasa manasa Moore and White Commodore Parasarpa dudu dudu Westwood, are restricted to the eastern Himalaya, northeastern India and Myanmar.  Two other species, Tawny Mime Chiasa agestor agestor (Gray and Himalayan Spotted Flat Celaenorrhinus munda Moore have been only rarely recorded from Bhutan and a few individuals of the rare Bhutan Glory Bhutanitis lidderdalei Atkinson were also recorded near Bunakha.  

  15. Fluxes of trichloroacetic acid through a conifer forest canopy

    International Nuclear Information System (INIS)

    Stidson, R.T.; Heal, K.V.; Dickey, C.A.; Cape, J.N.; Heal, M.R.

    2004-01-01

    Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, ∼1.4 x rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only ∼1-2% of above-canopy deposition. On average, ∼800 μg m -2 of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of ∼400 and ∼300 μg m -2 for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values (∼±50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50-200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric origin into mature forest canopies, as has been shown for seedlings (in

  16. Predicting impacts of climate change on the aboveground carbon sequestration rate of a temperate forest in northeastern China.

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    Jun Ma

    Full Text Available The aboveground carbon sequestration rate (ACSR reflects the influence of climate change on forest dynamics. To reveal the long-term effects of climate change on forest succession and carbon sequestration, a forest landscape succession and disturbance model (LANDIS Pro7.0 was used to simulate the ACSR of a temperate forest at the community and species levels in northeastern China based on both current and predicted climatic data. On the community level, the ACSR of mixed Korean pine hardwood forests and mixed larch hardwood forests, fluctuated during the entire simulation, while a large decline of ACSR emerged in interim of simulation in spruce-fir forest and aspen-white birch forests, respectively. On the species level, the ACSR of all conifers declined greatly around 2070s except for Korean pine. The ACSR of dominant hardwoods in the Lesser Khingan Mountains area, such as Manchurian ash, Amur cork, black elm, and ribbed birch fluctuated with broad ranges, respectively. Pioneer species experienced a sharp decline around 2080s, and they would finally disappear in the simulation. The differences of the ACSR among various climates were mainly identified in mixed Korean pine hardwood forests, in all conifers, and in a few hardwoods in the last quarter of simulation. These results indicate that climate warming can influence the ACSR in the Lesser Khingan Mountains area, and the largest impact commonly emerged in the A2 scenario. The ACSR of coniferous species experienced higher impact by climate change than that of deciduous species.

  17. Soil respiration response to prescribed burning and thinning in mixed-conifer and hardwood forests

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    Amy Concilio; Siyan Ma; Qinglin Li; James LeMoine; Jiquan Chen; Malcolm North; Daryl Moorhead; Randy Jensen

    2005-01-01

    The effects of management on soil carbon efflux in different ecosystems are still largely unknown yet crucial to both our understanding and management of global carbon flux. To compare the effects of common forest management practices on soil carbon cycling, we measured soil respiration rate (SRR) in a mixed-conifer and hardwood forest that had undergone various...

  18. Terrain and vegetation structural influences on local avian species richness in two mixed-conifer forests

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    Jody C. Vogeler; Andrew T. Hudak; Lee A. Vierling; Jeffrey Evans; Patricia Green; Kerri T. Vierling

    2014-01-01

    Using remotely-sensed metrics to identify regions containing high animal diversity and/or specific animal species or guilds can help prioritize forest management and conservation objectives across actively managed landscapes. We predicted avian species richness in two mixed conifer forests, Moscow Mountain and Slate Creek, containing different management contexts and...

  19. Long-term demographic trends in a fire-suppressed mixed-conifer forest

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    Carrie R. Levine; Flora Krivak-Tetley; Natalie S. van Doorn; Jolie-Anne S. Ansley; John J. Battles

    2016-01-01

    In the western United States, forests are experiencing novel environmental conditions related to a changing climate and a suppression of the historical fire regime. Mixed-conifer forests, considered resilient to disturbance due to their heterogeneity in structure and composition, appear to be shifting to a more homogeneous state, but the timescale of these shifts is...

  20. Silviculture for restoration of degraded temperate and boreal forests

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    John A. Stanturf; Palle Madsen; Emile S. Gardiner

    2004-01-01

    Throughout the temperate and boreal zones, human intervention has influenced landscapes and forests for millennia. The degree of human disturbance has only been constrained by the technology and resources available to different cultures and by time since initial habitation. Humans have influenced forests by regulating populations of browsers, clearing for agriculture,...

  1. Succession influences wild bees in a temperate forest landscape: the value of early successional stages in naturally regenerated and planted forests.

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    Taki, Hisatomo; Okochi, Isamu; Okabe, Kimiko; Inoue, Takenari; Goto, Hideaki; Matsumura, Takeshi; Makino, Shun'ichi

    2013-01-01

    In many temperate terrestrial forest ecosystems, both natural human disturbances drive the reestablishment of forests. Succession in plant communities, in addition to reforestation following the creation of open sites through harvesting or natural disturbances, can affect forest faunal assemblages. Wild bees perform an important ecosystem function in human-altered and natural or seminatural ecosystems, as they are essential pollinators for both crops and wild flowering plants. To maintain high abundance and species richness for pollination services, it is important to conserve and create seminatural and natural land cover with optimal successional stages for wild bees. We examined the effects of forest succession on wild bees. In particular, we evaluated the importance of early successional stages for bees, which has been suspected but not previously demonstrated. A range of successional stages, between 1 and 178 years old, were examined in naturally regenerated and planted forests. In total 4465 wild bee individuals, representing 113 species, were captured. Results for total bees, solitary bees, and cleptoparasitic bees in both naturally regenerated and planted conifer forests indicated a higher abundance and species richness in the early successional stages. However, higher abundance and species richness of social bees in naturally regenerated forest were observed as the successional stages progressed, whereas the abundance of social bees in conifer planted forest showed a concave-shaped relationship when plotted. The results suggest that early successional stages of both naturally regenerated and conifer planted forest maintain a high abundance and species richness of solitary bees and their cleptoparasitic bees, although social bees respond differently in the early successional stages. This may imply that, in some cases, active forest stand management policies, such as the clear-cutting of planted forests for timber production, would create early successional

  2. Succession influences wild bees in a temperate forest landscape: the value of early successional stages in naturally regenerated and planted forests.

    Directory of Open Access Journals (Sweden)

    Hisatomo Taki

    Full Text Available In many temperate terrestrial forest ecosystems, both natural human disturbances drive the reestablishment of forests. Succession in plant communities, in addition to reforestation following the creation of open sites through harvesting or natural disturbances, can affect forest faunal assemblages. Wild bees perform an important ecosystem function in human-altered and natural or seminatural ecosystems, as they are essential pollinators for both crops and wild flowering plants. To maintain high abundance and species richness for pollination services, it is important to conserve and create seminatural and natural land cover with optimal successional stages for wild bees. We examined the effects of forest succession on wild bees. In particular, we evaluated the importance of early successional stages for bees, which has been suspected but not previously demonstrated. A range of successional stages, between 1 and 178 years old, were examined in naturally regenerated and planted forests. In total 4465 wild bee individuals, representing 113 species, were captured. Results for total bees, solitary bees, and cleptoparasitic bees in both naturally regenerated and planted conifer forests indicated a higher abundance and species richness in the early successional stages. However, higher abundance and species richness of social bees in naturally regenerated forest were observed as the successional stages progressed, whereas the abundance of social bees in conifer planted forest showed a concave-shaped relationship when plotted. The results suggest that early successional stages of both naturally regenerated and conifer planted forest maintain a high abundance and species richness of solitary bees and their cleptoparasitic bees, although social bees respond differently in the early successional stages. This may imply that, in some cases, active forest stand management policies, such as the clear-cutting of planted forests for timber production, would create

  3. Management options for mitigating Nitrogen (N) losses from N-saturated mixed-conifer forests in California

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    Benjamin S. Gimeno; Fengming Yuan; Mark E. Fenn; Thomas Meixner

    2009-01-01

    Mixed-conifer forests of southern California are exposed to nitrogen (N) deposition levels that impair carbon (C) and N cycling, enhance forest flammability, increase the risk of fire occurrence and air pollution emissions in fire, and increase nitrate...

  4. Small Sample Sizes Yield Biased Allometric Equations in Temperate Forests

    OpenAIRE

    Duncanson, L.; Rourke, O.; Dubayah, R.

    2015-01-01

    Accurate quantification of forest carbon stocks is required for constraining the global carbon cycle and its impacts on climate. The accuracies of forest biomass maps are inherently dependent on the accuracy of the field biomass estimates used to calibrate models, which are generated with allometric equations. Here, we provide a quantitative assessment of the sensitivity of allometric parameters to sample size in temperate forests, focusing on the allometric relationship between tree height a...

  5. Oceanic temperate forest versus warm temperate rainforest: a reply to Grubb et al. (2017)

    DEFF Research Database (Denmark)

    McGlone, Matt S.; Buitenwerf, Robert; Richardson, Sarah J.

    2017-01-01

    Grubb et al. (2017) point out that we (McGlone et al. 2016) erroneously stated that the definition of warm temperate rain forest (WTRF; Grubb et al. 2013) was based in part on climatic criteria. We apologise: their text made clear that this was not the case. However, they go on to say that they ‘...

  6. Effects of conifers and elk browsing on quaking aspen forests in the central Rocky Mountains, USA

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    Kaye, Margot W.; Binkley, Dan; Stohlgren, Thomas J.

    2005-01-01

    Elk browsing and conifer species mixing with aspen (Populus tremuloides Michx.) present current challenges to aspen forest management in the western United States. We evaluated the effects of conifers and elk browsing on quaking aspen stands in and near Rocky Mountain National Park using tree rings to reconstruct patterns of aspen establishment, growth, and mortality over the past 120 years. High conifer encroachment and elk browse were both associated with decreased aspen recruitment, with mean recruitment dropping over 30% from pure aspen to mixed stands and over 50% from low-browse to high-browse stands. Maximum aspen recruitment was lower in mixed stands than in pure stands with the same tree basal area. High levels of elk browsing were also associated with a 30% decrease in stand-level growth of aspen. Neither high conifer abundance nor elk browse affected the growth of individual trees or aspen mortality. Aspen establishment was negatively influenced by conifers and elk browsing; however, aspen growth and mortality appeared to be resilient to these two external influences. Overall, these results suggest that long-term preservation of aspen forests could be achieved by enhancing aspen recruitment.

  7. Animal damage to conifers on national forests in the Pacific Northwest region.

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    Glenn L. Crouch

    1969-01-01

    Animal damage to conifers is a timely topic in the Pacific Northwest. Foresters in this Region are increasingly concerned and perplexed by damage caused by animals to natural and planted seedlings and larger growing stock. Nearly every animal inhabiting for st land is believed to injure seedlings and small trees to some degree. Mice girdle small trees, and bears girdle...

  8. Diagnosis of Annosus Root Disease in Mixed Conifer Forests in the Northwestern United States

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    Craig L. Schmitt

    1989-01-01

    Recognizing annosus root disease affecting conifers in northwestern United States forests is discussed. Field diagnosis can bemade by observing characteristic stand patterns, wood stain and decay, ectotrophic mycelium, and sporophores. Most seriously affected trees include hemlocks, grand fir, white fir and Pacific silver fir. Ponderosa pine and other true firs may...

  9. Postfire seed rain of black spruce, a semiserotinous conifer, in forests of interior Alaska

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    Jill Johnstone; Leslie Boby; Emily Tissier; Michelle Mack; Dave Verbyla; Xanthe. Walker

    2009-01-01

    The availability of viable seed can act as an important constraint on plant regeneration following disturbance. This study presents data on seed quantity and quality for black spruce (Picea mariana (Mill.) B.S.P.), a semiserotinous conifer that dominates large areas of North American boreal forest. We sampled seed rain and viability for 2 years...

  10. Habitat correlates of the red panda in the temperate forests of Bhutan.

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    Dorji, Sangay; Vernes, Karl; Rajaratnam, Rajanathan

    2011-01-01

    Anthropogenic activities and associated global climate change are threatening the biodiversity in the Himalayas against a backdrop of poor knowledge of the region's threatened species. The red panda (Ailurus fulgens) is a threatened mammal confined to the eastern Himalayas, and because of Bhutan's central location in the distributional range of red pandas, its forests are integral to the long-term viability of wild populations. Detailed habitat requirements of the red panda are largely speculative, and there is virtually no ecological information available on this species in Bhutan. Between 2007 and 2009, we established 615 presence/absence plots in a systematic sampling of resident habitat types within Jigme Dorji and Thrumshingla National Parks, Bhutan, to investigate broad and fine-scale red panda habitat associations. Additional locality records of red pandas were obtained from interviewing 664 park residents. Red pandas were generally confined to cool broadleaf and conifer forests from 2,110-4,389 m above sea level (asl), with the majority of records between 2,400-3,700 m asl on south and east-facing slopes. At a finer scale, multivariate analysis revealed that red pandas were strongly associated with old growth Bhutan Fir (Abies densa) forest dominated by a dense cover of Yushania and Arundanaria bamboo with a high density of fallen logs and tree stumps at ground level; a high density of trees, dead snags, and rhododendron shrubs in the mid-storey; and locations that were close to water. Because Bhutan's temperate forests that encompass prime red panda habitat are also integral to human subsistence and socio-economic development, there exists an inadvertent conflict between the needs of people and red pandas. As such, careful sustainable management of Bhutan's temperate forests is necessary if a balance is to be met between the socioeconomic needs of people and the conservation goals for red pandas.

  11. Habitat correlates of the red panda in the temperate forests of Bhutan.

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    Sangay Dorji

    Full Text Available Anthropogenic activities and associated global climate change are threatening the biodiversity in the Himalayas against a backdrop of poor knowledge of the region's threatened species. The red panda (Ailurus fulgens is a threatened mammal confined to the eastern Himalayas, and because of Bhutan's central location in the distributional range of red pandas, its forests are integral to the long-term viability of wild populations. Detailed habitat requirements of the red panda are largely speculative, and there is virtually no ecological information available on this species in Bhutan. Between 2007 and 2009, we established 615 presence/absence plots in a systematic sampling of resident habitat types within Jigme Dorji and Thrumshingla National Parks, Bhutan, to investigate broad and fine-scale red panda habitat associations. Additional locality records of red pandas were obtained from interviewing 664 park residents. Red pandas were generally confined to cool broadleaf and conifer forests from 2,110-4,389 m above sea level (asl, with the majority of records between 2,400-3,700 m asl on south and east-facing slopes. At a finer scale, multivariate analysis revealed that red pandas were strongly associated with old growth Bhutan Fir (Abies densa forest dominated by a dense cover of Yushania and Arundanaria bamboo with a high density of fallen logs and tree stumps at ground level; a high density of trees, dead snags, and rhododendron shrubs in the mid-storey; and locations that were close to water. Because Bhutan's temperate forests that encompass prime red panda habitat are also integral to human subsistence and socio-economic development, there exists an inadvertent conflict between the needs of people and red pandas. As such, careful sustainable management of Bhutan's temperate forests is necessary if a balance is to be met between the socioeconomic needs of people and the conservation goals for red pandas.

  12. Hurricane Impacts to Tropical and Temperate Forest Landscapes

    OpenAIRE

    Boose, Emery Robert; Foster, David Russell; Fluet, Marcheterre

    1994-01-01

    Hurricanes represent an important natural disturbance process to tropical and temperate forests in many coastal areas of the world. The complex patterns of damage created in forests by hurricane winds result from the interaction of meteorological, physiographic, and biotic factors on a range of spatial scales. To improve our understanding of these factors and of the role of catastrophic hurricane wind as a disturbance process, we take an integrative approach. A simple meteorological model (HU...

  13. The effects of climate stability on northern temperate forests

    DEFF Research Database (Denmark)

    Ma, Ziyu

    2016-01-01

    . The evolutionary relationship among species is known as phylogeny. Tree diversity was mapped using a phylogenetic supertree, covering species in the temperate forests of North America, Europe, and China. I found that Quaternary climate fluctuations limited phylogenetic endemism, which quantified unique...

  14. Carbon sequestration in managed temperate coniferous forests under climate change

    Science.gov (United States)

    Dymond, Caren C.; Beukema, Sarah; Nitschke, Craig R.; Coates, K. David; Scheller, Robert M.

    2016-03-01

    Management of temperate forests has the potential to increase carbon sinks and mitigate climate change. However, those opportunities may be confounded by negative climate change impacts. We therefore need a better understanding of climate change alterations to temperate forest carbon dynamics before developing mitigation strategies. The purpose of this project was to investigate the interactions of species composition, fire, management, and climate change in the Copper-Pine Creek valley, a temperate coniferous forest with a wide range of growing conditions. To do so, we used the LANDIS-II modelling framework including the new Forest Carbon Succession extension to simulate forest ecosystems under four different productivity scenarios, with and without climate change effects, until 2050. Significantly, the new extension allowed us to calculate the net sector productivity, a carbon accounting metric that integrates aboveground and belowground carbon dynamics, disturbances, and the eventual fate of forest products. The model output was validated against literature values. The results implied that the species optimum growing conditions relative to current and future conditions strongly influenced future carbon dynamics. Warmer growing conditions led to increased carbon sinks and storage in the colder and wetter ecoregions but not necessarily in the others. Climate change impacts varied among species and site conditions, and this indicates that both of these components need to be taken into account when considering climate change mitigation activities and adaptive management. The introduction of a new carbon indicator, net sector productivity, promises to be useful in assessing management effectiveness and mitigation activities.

  15. Modeling climate and fuel reduction impacts on mixed-conifer forest carbon stocks in the Sierra Nevada, California

    Science.gov (United States)

    Matthew D. Hurteau; Timothy A. Robards; Donald Stevens; David Saah; Malcolm North; George W. Koch

    2014-01-01

    Quantifying the impacts of changing climatic conditions on forest growth is integral to estimating future forest carbon balance. We used a growth-and-yield model, modified for climate sensitivity, to quantify the effects of altered climate on mixed-conifer forest growth in the Lake Tahoe Basin, California. Estimates of forest growth and live tree carbon stocks were...

  16. Responses of temperate forest productivity to insect and pathogen disturbances

    Science.gov (United States)

    Flower, C. E.; Gonzalez-Meler, M. A.

    2014-12-01

    Climate forcing factors have been documented to directly (e.g. CO2 fertilization) or indirectly (e.g. temperature and vapor pressure deficit) affect net primary productivity (NPP) of forests. Climate variations can also affect the vulnerability of forests to pests and pathogens, causing diffuse or widespread mortality. The introduction of novel pests is causing rapid mortality of targeted species with undetermined effects on forest productivity: NPP could decrease or increase depending on the severity (proportion of basal area impacted) and species diversity. We attempted to document the impact of diffuse mortality caused by insect outbreaks on North American temperate forests through synthesis of literature. Despite the large number of studies (>500) only a few (12) documented NPP in a systematic manner. The magnitude of insect and pathogen disturbance was larger in western than eastern forests due to the redundancy and functional diversity of temperate deciduous and mixed deciduous forests. Recovery from disturbance was more rapid from diffuse short duration defoliation events relative to the long lasting impacts of wood boring insects. Forest resilience may decrease as insect disturbance increases, particularly with generalist invasive pests that target a variety of species. We conclude that these biotic interactions, particularly when caused by invasive pests, impose biological forcing to forest NPP at similar magnitude and time scales than climate forcing.

  17. Carbon density and distribution of six Chinese temperate forests.

    Science.gov (United States)

    Zhang, QuanZhi; Wang, ChuanKuan

    2010-07-01

    Quantifying forest carbon (C) storage and distribution is important for forest C cycling studies and terrestrial ecosystem modeling. Forest inventory and allometric approaches were used to measure C density and allocation in six representative temperate forests of similar stand age (42-59 years old) and growing under the same climate in northeastern China. The forests were an aspen-birch forest, a hardwood forest, a Korean pine plantation, a Dahurian larch plantation, a mixed deciduous forest, and a Mongolian oak forest. There were no significant differences in the C densities of ecosystem components (except for detritus) although the six forests had varying vegetation compositions and site conditions. However, the differences were significant when the C pools were normalized against stand basal area. The total ecosystem C density varied from 186.9 tC hm(-2) to 349.2 tC hm(-2) across the forests. The C densities of vegetation, detritus, and soil ranged from 86.3-122.7 tC hm(-2), 6.5-10.5 tC hm(-2), and 93.7-220.1 tC hm(-2), respectively, which accounted for 39.7% +/- 7.1% (mean +/- SD), 3.3% +/- 1.1%, and 57.0% +/- 7.9% of the total C densities, respectively. The overstory C pool accounted for > 99% of the total vegetation C pool. The foliage biomass, small root (diameter forests, while the Dahurian larch plantation had the highest small root production efficiency (total biomass/small root biomass: 124.7 g g(-1)). The small root C density decreased with soil depth for all forests except for the Mongolian oak forest, in which the small roots tended to be vertically distributed downwards. The C density of coarse woody debris was significantly less in the two plantations than in the four naturally regenerated forests. The variability of C allocation patterns in a specific forest is jointly influenced by vegetation type, management history, and local water and nutrient availability. The study provides important data for developing and validating C cycling models for

  18. Rainforest birds: A land manager's guide to breeding bird habitat in young conifer forests in the Pacific Northwest

    Science.gov (United States)

    Altman, Bob; Hagar, Joan

    2007-01-01

    This document (hereafter Guide) has been prepared to assist land managers interested in conducting conservation and management activities to benefit breeding birds associated with young conifer forests in the Pacific Northwest. Audiences targeted for use of the Guide include land trusts, watershed councils, non-commercial private land owners, forest products companies, land-managing conservation organizations, government agencies, tribes, and First Nations. We hope the Guide will be a useful and valuable tool to support any of the variety of reasons to manage for bird habitat in young conifer forests (for example, regulatory, biodiversity, bird conservation, and forest certification standards).

  19. Net ecosystem carbon exchange of a dry temperate eucalypt forest

    Science.gov (United States)

    Hinko-Najera, Nina; Isaac, Peter; Beringer, Jason; van Gorsel, Eva; Ewenz, Cacilia; McHugh, Ian; Exbrayat, Jean-François; Livesley, Stephen J.; Arndt, Stefan K.

    2017-08-01

    Forest ecosystems play a crucial role in the global carbon cycle by sequestering a considerable fraction of anthropogenic CO2, thereby contributing to climate change mitigation. However, there is a gap in our understanding about the carbon dynamics of eucalypt (broadleaf evergreen) forests in temperate climates, which might differ from temperate evergreen coniferous or deciduous broadleaved forests given their fundamental differences in physiology, phenology and growth dynamics. To address this gap we undertook a 3-year study (2010-2012) of eddy covariance measurements in a dry temperate eucalypt forest in southeastern Australia. We determined the annual net carbon balance and investigated the temporal (seasonal and inter-annual) variability in and environmental controls of net ecosystem carbon exchange (NEE), gross primary productivity (GPP) and ecosystem respiration (ER). The forest was a large and constant carbon sink throughout the study period, even in winter, with an overall mean NEE of -1234 ± 109 (SE) g C m-2 yr-1. Estimated annual ER was similar for 2010 and 2011 but decreased in 2012 ranging from 1603 to 1346 g C m-2 yr-1, whereas GPP showed no significant inter-annual variability, with a mean annual estimate of 2728 ± 39 g C m-2 yr-1. All ecosystem carbon fluxes had a pronounced seasonality, with GPP being greatest during spring and summer and ER being highest during summer, whereas peaks in NEE occurred in early spring and again in summer. High NEE in spring was likely caused by a delayed increase in ER due to low temperatures. A strong seasonal pattern in environmental controls of daytime and night-time NEE was revealed. Daytime NEE was equally explained by incoming solar radiation and air temperature, whereas air temperature was the main environmental driver of night-time NEE. The forest experienced unusual above-average annual rainfall during the first 2 years of this 3-year period so that soil water content remained relatively high and the forest

  20. Community structures of Mesostigmata, Prostigmata and Oribatida in broad-leaved regeneration forests and conifer plantations of various ages.

    Science.gov (United States)

    Hasegawa, Motohiro; Okabe, Kimiko; Fukuyama, Kenji; Makino, Shun'ichi; Okochi, Isamu; Tanaka, Hiroshi; Goto, Hideaki; Mizoguchi, Takeo; Sakata, Tadashi

    2013-04-01

    The community structures of Mesostigmata, Prostigmata, and Oribatida in the soil of broad-leaved regeneration forests and conifer plantations of various ages were assessed alongside soil and plant environmental variables using three response metrics (density, species richness, and species-abundance distribution). The density and species richness of mites recovered swiftly after clear-cutting or replanting. Oribatid mites dominated the soil mite communities in terms of densities and species richness for both forest types. Soil mite communities in broad-leaved forests was related to forest age, the crown tree communities index, and forest-floor litter weight. In contrast, soil mite communities in the conifer plantation sites were related to various indices of understory plants. The development of the understory plants was synchronized with the silvicultural schedules, including a closed canopy and thinning. Such a conifer plantation management may affect indirectly the community of mites.

  1. Wildlife species associated with non-coniferous vegetation in Pacific Northwest conifer forests: A review

    Science.gov (United States)

    Hagar, J.C.

    2007-01-01

    Non-coniferous vegetation, including herbs, shrubs, and broad-leaved trees, makes a vital contribution to ecosystem function and diversity in Pacific Northwest conifer forests. However, forest management has largely been indifferent or detrimental to shrubs and trees that have low commercial value, in spite of a paradigm shift towards more holistic management in recent decades. Forest management practices that are detrimental to broad-leaved trees and shrubs are likely to decrease habitat diversity for wildlife, but the number of species that may be affected has not previously been enumerated. I reviewed life history accounts for forest-dwelling vertebrate wildlife species and derived a list of 78 species in Oregon and Washington that are associated with non-coniferous vegetation. The diversity of direct and indirect food resources provided was the primary functional basis for associations of most species with non-coniferous vegetation. Thus, a diversity of herbs and broad-leaved trees and shrubs provides the foundation for food webs that contribute to diversity at multiple trophic levels in Pacific Northwest conifer forests. Given the number of species associated with non-coniferous vegetation in conifer-dominated forests, maintaining habitats that support diverse plant communities, particularly broad-leaved trees and shrubs, will be an important component of management strategies intended to foster biodiversity. Silvicultural practices such as modified planting densities, and pre-commercial and commercial thinning, can be used to control stand density in order to favor the development of understory herbs, shrubs, and a diversity of tree species within managed stands. Allowing shrubs and hardwood trees to develop and persist in early seral stands by curtailing vegetation control also would benefit many species associated with non-coniferous vegetation.

  2. Nuclear DNA content affects the productivity of conifer forests by altering hydraulic architecture

    Science.gov (United States)

    Alday, Josu; Resco de Dios, Víctor

    2014-05-01

    Predictions of future global climate rely on feedbacks between terrestrial vegetation and the global carbon cycle, but the exact mechanisms underlying this relationship are still being discussed. One of the key knowledge gaps lies on the scaling of cellular processes to the ecosystem level. Here we examine whether an under-explored plant trait, inter-specific variation in the bulk amount of DNA in unreplicated somatic cells (2C DNA content), can explain inter-specific variation in the maximum productivity of conifer forests. We expected 2C DNA content to be negatively related to conifer productivity because: 1) it is positively correlated with cell volume (which, in turn, potentially affects structural features such as leaf mass area, a strong predictor of photosynthetic capacity); 2) it is positively correlated with stomatal size (with larger stomata leading to lower overall stomatal conductance and, by extension, lower CO2 uptake); and 3) larger genome sizes may reduce P availability in RNA (which has been hypothesized to slow growth). We present the results of regression and independent contrasts in different monospecific forests encompassing a 52º latitudinal gradient, each being dominated by 1 of 35 different conifer species. Contrary to expectations, we observed a positive correlation between genome size and maximum Gross Primary Productivity (R2 = 0.47) and also between genome size maximum tree height (R2 = 0.27). This correlation was apparently driven by the effects of genome size on stem hydraulics, since 2C DNA was positively correlated with wood density (R2 = 0.40) and also with resistance to cavitation (P50, R2 = 0.28). That is, increased genome sizes have a positive effect on the productivity of conifer forests by affecting the vascular tissues to increase their capacity for water transport. Our results shed a new light on the evolution of the vascular system of conifer forests and how they affect ecosystem productivity, and indicate the potential to

  3. Fire-return intervals in mixed-conifer forests of the Kings River Sustainable Forest Ecosystems Project area

    Science.gov (United States)

    Catherine Phillips

    2002-01-01

    Fire-return intervals were studied on six 1.4-ha plots in a 2,070-ha study area in the Dinkey Creek watershed. Stumps in mixed-conifer forest were examined for fire scars created from 1771 to 1994, with 1873 chosen as the end of the pre-Euro-American settlement period because the rate of fire events decreased on most plots after about that year. Mean intervals from...

  4. Can Carbon Fluxes Explain Differences in Soil Organic Carbon Storage under Aspen and Conifer Forest Overstories?

    Directory of Open Access Journals (Sweden)

    Antra Boča

    2017-04-01

    Full Text Available Climate- and management-induced changes in tree species distributions are raising questions regarding tree species-specific effects on soil organic carbon (SOC storage and stability. Quaking aspen (Populus tremuloides Michx. is the most widespread tree species in North America, but fire exclusion often promotes the succession to conifer dominated forests. Aspen in the Western US have been found to store more SOC in the mineral soil than nearby conifers, but we do not yet fully understand the source of this differential SOC accumulation. We measured total SOC storage (0–50 cm, characterized stable and labile SOC pools, and quantified above- and belowground litter inputs and dissolved organic carbon (DOC fluxes during snowmelt in plots located in N and S Utah, to elucidate the role of foliage vs. root detritus in SOC storage and stabilization in both ecosystems. While leaf litterfall was twice as high under aspen as under conifers, input of litter-derived DOC with snowmelt water was consistently higher under conifers. Fine root (<2 mm biomass, estimated root detritus input, and root-derived DOC fluxes were also higher under conifers. A strong positive relationship between root and light fraction C content suggests that root detritus mostly fueled the labile fraction of SOC. Overall, neither differences in above- and belowground detritus C inputs nor in detritus-derived DOC fluxes could explain the higher and more stable SOC pools under aspen. We hypothesize that root–microbe–soil interactions in the rhizosphere are more likely to drive these SOC pool differences.

  5. Repeated wildfires alter forest recovery of mixed-conifer ecosystems.

    Science.gov (United States)

    Stevens-Rumann, Camille; Morgan, Penelope

    2016-09-01

    Most models project warmer and drier climates that will contribute to larger and more frequent wildfires. However, it remains unknown how repeated wildfires alter post-fire successional patterns and forest structure. Here, we test the hypothesis that the number of wildfires, as well as the order and severity of wildfire events interact to alter forest structure and vegetation recovery and implications for vegetation management. In 2014, we examined forest structure, composition, and tree regeneration in stands that burned 1-18 yr before a subsequent 2007 wildfire. Three important findings emerged: (1) Repeatedly burned forests had 15% less woody surface fuels and 31% lower tree seedling densities compared with forests that only experienced one recent wildfire. These repeatedly burned areas are recovering differently than sites burned once, which may lead to alternative ecosystem structure. (2) Order of burn severity (high followed by low severity compared with low followed by high severity) did influence forest characteristics. When low burn severity followed high, forests had 60% lower canopy closure and total basal area with 92% fewer tree seedlings than when high burn severity followed low. (3) Time between fires had no effect on most variables measured following the second fire except large woody fuels, canopy closure and tree seedling density. We conclude that repeatedly burned areas meet many vegetation management objectives of reduced fuel loads and moderate tree seedling densities. These differences in forest structure, composition, and tree regeneration have implications not only for the trajectories of these forests, but may reduce fire intensity and burn severity of subsequent wildfires and may be used in conjunction with future fire suppression tactics. © 2016 by the Ecological Society of America.

  6. Convergence, Consilience, and the Evolution of Temperate Deciduous Forests.

    Science.gov (United States)

    Edwards, Erika J; Chatelet, David S; Chen, Bo-Chang; Ong, Jin Yao; Tagane, Shuichiro; Kanemitsu, Hironobu; Tagawa, Kazuki; Teramoto, Kentaro; Park, Brian; Chung, Kuo-Fang; Hu, Jer-Ming; Yahara, Tetsukazu; Donoghue, Michael J

    2017-08-01

    The deciduous habit of northern temperate trees and shrubs provides one of the most obvious examples of convergent evolution, but how did it evolve? Hypotheses based on the fossil record posit that deciduousness evolved first in response to drought or darkness and preadapted certain lineages as cold climates spread. An alternative is that evergreens first established in freezing environments and later evolved the deciduous habit. We monitored phenological patterns of 20 species of Viburnum spanning tropical, lucidophyllous (subtropical montane and warm temperate), and cool temperate Asian forests. In lucidophyllous forests, all viburnums were evergreen plants that exhibited coordinated leaf flushes with the onset of the rainy season but varied greatly in the timing of leaf senescence. In contrast, deciduous species exhibited tight coordination of both flushing and senescence, and we found a perfect correlation between the deciduous habit and prolonged annual freezing. In contrast to previous stepwise hypotheses, a consilience of independent lines of evidence supports a lockstep model in which deciduousness evolved in situ, in parallel, and concurrent with a gradual cooling climate. A pervasive selective force combined with the elevated evolutionary accessibility of a particular response may explain the massive convergence of adaptive strategies that characterizes the world's biomes.

  7. Canopy structure of tropical and sub-tropical rain forests in relation to conifer dominance analysed with a portable LIDAR system.

    Science.gov (United States)

    Aiba, Shin-ichiro; Akutsu, Kosuke; Onoda, Yusuke

    2013-12-01

    Globally, conifer dominance is restricted to nutient-poor habitats in colder, drier or waterlogged environments, probably due to competition with angiosperms. Analysis of canopy structure is important for understanding the mechanism of plant coexistence in relation to competition for light. Most conifers are shade intolerant, and often have narrow, deep, conical crowns. In this study it is predicted that conifer-admixed forests have less distinct upper canopies and more undulating canopy surfaces than angiosperm-dominated forests. By using a ground-based, portable light detection and ranging (LIDAR) system, canopy structure was quantified for old-growth evergreen rainforests with varying dominance of conifers along altitudinal gradients (200-3100 m a.s.l.) on tropical and sub-tropical mountains (Mount Kinabalu, Malaysian Borneo and Yakushima Island, Japan) that have different conifer floras. Conifers dominated at higher elevations on both mountains (Podocarpaceae and Araucariaceae on Kinabalu and Cupressaceae and Pinaceae on Yakushima), but conifer dominance also varied with soil/substrate conditions on Kinabalu. Conifer dominance was associated with the existence of large-diameter conifers. Forests with higher conifer dominance showed a canopy height profile (CHP) more skewed towards the understorey on both Kinabalu and Yakushima. In contrast, angiosperm-dominated forests had a CHP skewed towards upper canopy, except for lowland dipterocarp forests and a sub-alpine scrub dominated by small-leaved Leptospermum recurvum (Myrtaceae) on Kinabalu. Forests with a less dense upper canopy had more undulating outer canopy surfaces. Mixed conifer-angiosperm forests on Yakushima and dipterocarp forests on Kinabalu showed similar canopy structures. The results generally supported the prediction, suggesting that lower growth of angiosperm trees (except L. recurvum on Kinabalu) in cold and nutrient-poor environments results in a sparser upper canopy, which allows shade

  8. Comparative trends in log populations in northern Arizona mixed-conifer and ponderosa pine forests following severe drought

    Science.gov (United States)

    Joseph L. Ganey; Scott C. Vojta

    2017-01-01

    Logs provide an important form of coarse woody debris in forest systems, contributing to numerous ecological processes and affecting wildlife habitat and fuel complexes. Despite this, little information is available on the dynamics of log populations in southwestern ponderosa pine (Pinus ponderosa) and especially mixed-conifer forests. A recent episode of elevated tree...

  9. Predicting surface fuel models and fuel metrics using lidar and CIR imagery in a dense mixed conifer forest

    Science.gov (United States)

    Marek K. Jakubowksi; Qinghua Guo; Brandon Collins; Scott Stephens; Maggi. Kelly

    2013-01-01

    We compared the ability of several classification and regression algorithms to predict forest stand structure metrics and standard surface fuel models. Our study area spans a dense, topographically complex Sierra Nevada mixed-conifer forest. We used clustering, regression trees, and support vector machine algorithms to analyze high density (average 9 pulses/m

  10. Post-fire management regimes affect carbon sequestration and storage in a Sierra Nevada mixed conifer forest

    Science.gov (United States)

    Elizabeth M. Powers; John D. Marshall; Jianwei Zhang; Liang Wei

    2013-01-01

    Forests mitigate climate change by sequestering CO2 from the atmosphere and accumulating it in biomass storage pools. However, in dry conifer forests, fire occasionally returns large quantities of CO2 to the atmosphere. Both the total amount of carbon stored and its susceptibility to loss may be altered by post-fire land...

  11. The ecology and management of moist mixed-conifer forests in eastern Oregon and Washington: a synthesis of the relevant biophysical science and implications for future land management

    Science.gov (United States)

    Peter Stine; Paul Hessburg; Thomas Spies; Marc Kramer; Christopher J. Fettig; Andrew Hansen; John Lehmkuhl; Kevin O' Hara; Karl Polivka; Peter Singleton; Susan Charnley; Andrew Merschel; Rachel. White

    2014-01-01

    Land managers in the Pacific Northwest have reported a need for updated scientific information on the ecology and management of mixed-conifer forests east of the Cascade Range in Oregon and Washington. Of particular concern are the moist mixed-conifer forests, which have become drought-stressed and vulnerable to high-severity fire after decades of human disturbances...

  12. Xylem traits, leaf longevity and growth phenology predict growth and mortality response to defoliation in northern temperate forests.

    Science.gov (United States)

    Foster, Jane R

    2017-09-01

    Defoliation outbreaks are biological disturbances that alter tree growth and mortality in temperate forests. Trees respond to defoliation in many ways; some recover rapidly, while others decline gradually or die. Functional traits such as xylem anatomy, growth phenology or non-structural carbohydrate (NSC) storage could explain these responses, but idiosyncratic measures used by defoliation studies have frustrated efforts to generalize among species. Here, I test for functional differences with published growth and mortality data from 37 studies, including 24 tree species and 11 defoliators from North America and Eurasia. I synthesized data into standardized variables suitable for numerical models and used linear mixed-effects models to test the hypotheses that responses to defoliation vary among species and functional groups. Standardized data show that defoliation responses vary in shape and degree. Growth decreased linearly or curvilinearly, least in ring-porous Quercus and deciduous conifers (by 10-40% per 100% defoliation), whereas growth of diffuse-porous hardwoods and evergreen conifers declined by 40-100%. Mortality increased exponentially with defoliation, most rapidly for evergreen conifers, then diffuse-porous, then ring-porous species and deciduous conifers (Larix). Goodness-of-fit for functional-group models was strong (R2c = 0.61-0.88), if lower than species-specific mixed-models (R2c = 0.77-0.93), providing useful alternatives when species data are lacking. These responses are consistent with functional differences in leaf longevity, wood growth phenology and NSC storage. When defoliator activity lags behind wood-growth, either because xylem-growth precedes budburst (Quercus) or defoliator activity peaks later (sawflies on Larix), impacts on annual wood-growth will always be lower. Wood-growth phenology of diffuse-porous species and evergreen conifers coincides with defoliation and responds more drastically, and lower axial NSC storage makes them

  13. Fruiting and flushing phenology in Asian tropical and temperate forests: implications for primate ecology.

    Science.gov (United States)

    Hanya, Goro; Tsuji, Yamato; Grueter, Cyril C

    2013-04-01

    In order to understand the ecological adaptations of primates to survive in temperate forests, we need to know the general patterns of plant phenology in temperate and tropical forests. Comparative analyses have been employed to investigate general trends in the seasonality and abundance of fruit and young leaves in tropical and temperate forests. Previous studies have shown that (1) fruit fall biomass in temperate forest is lower than in tropical forest, (2) non-fleshy species, in particular acorns, comprise the majority of the fruit biomass in temperate forest, (3) the duration of the fruiting season is shorter in temperate forest, and (4) the fruiting peak occurs in autumn in most temperate forests. Through our comparative analyses of the fruiting and flushing phenology between Asian temperate and tropical forests, we revealed that (1) fruiting is more annually periodic (the pattern in one year is similar to that seen in the next year) in temperate forest in terms of the number of fruiting species or trees, (2) there is no consistent difference in interannual variations in fruiting between temperate and tropical forests, although some oak-dominated temperate forests exhibit extremely large interannual variations in fruiting, (3) the timing of the flushing peak is predictable (in spring and early summer), and (4) the duration of the flushing season is shorter. The flushing season in temperate forests (17-28 % of that in tropical forests) was quite limited, even compared to the fruiting season (68 %). These results imply that temperate primates need to survive a long period of scarcity of young leaves and fruits, but the timing is predictable. Therefore, a dependence on low-quality foods, such as mature leaves, buds, bark, and lichens, would be indispensable for temperate primates. Due to the high predictability of the timing of fruiting and flushing in temperate forests, fat accumulation during the fruit-abundant period and fat metabolization during the

  14. Leaching of nitrate from temperate forests - effects of air pollution and forest management

    DEFF Research Database (Denmark)

    Gundersen, Per; Schmidt, Inger Kappel; Raulund-Rasmussen, Karsten

    2006-01-01

    deposition (> 8-10 kg ha(-1) a(-1)). We synthesized the current understanding of factors controlling N leaching in relation to three primary causes of N cycle disruption: (i) Increased N input (air pollution, fertilization, N-2 fixing plants). In European forests, elevated N deposition explains approximately...... conifer forests receive higher N deposition and exhibit higher nitrate loss than deciduous forests; an exception is alder that shows substantial nitrate leaching through N fixation input. Fertilization with N poses limited risk to water quality, when applied to N-limited forests. (ii) Reduced plant uptake...... of the nitrate response is especially connected to the recovery of the vegetation sink. Less intensive disturbances like thinning have only minor effects on N loss. (iii) Enhanced mineralization of soil N (liming, ditching, climate change). Responses in nitrate leaching after liming may increase with N...

  15. Cone selection by Eurasian red squirrels in mixed conifer forests in the Italian Alps

    Science.gov (United States)

    Molinari, A.; Wauters, L. A.; Airoldi, G.; Cerinotti, F.; Martinoli, A.; Tosi, G.

    2006-07-01

    Tree squirrels are arboreal granivores that harvest and consume tree seeds both prior to and after seed-dispersal. Inter- and intraspecific patterns of seed predation suggest that squirrels may exert strong selective pressure on cone morphology and patterns of cone production, and suggest coevolutionary interactions between squirrels and conifers. In some pine species (genus Pinus), mutualistic relationships have evolved between cone (seed) traits and seed-dispersal behaviour by birds and rodents. In other species, feeding by seed predators has selected for cone traits that decrease intensity of seed consumption. In mixed conifer forests, red squirrels ( Sciurus vulgaris) feed intensively in some (target) trees but avoid others (nontarget trees). Here we explore defensive cone traits and seed traits correlated with tree selection for conifer species with different seed-dispersal strategies. No selection for cone traits existed in Pinus cembra, which has large wingless seeds, dispersed by birds and rodents. In Picea abies, the most favoured species, target trees had cones with more seeds per cone than nontarget trees, and number of seeds increased with cone length. Cone selection was most pronounced in Pinus sylvestris, where target trees had bigger cones with more seeds and higher total seed mass than nontarget trees. However, ratio of seed mass on cone mass did not differ among target and nontarget trees, suggesting that bigger cones also had more protective tissue, probably increasing difficulties for seed predators to gain access to seeds. Our results suggest that cone and seed traits of P. cembra facilitate seed consumption by squirrels, but that defensive cone traits of small-seeded conifers, in combination with annual differences in seed production (masting), might be the result of coevolution with seed-eating squirrels.

  16. The conversion of evenaged into unevenaged mixed conifer forests in southern British Columbia

    Energy Technology Data Exchange (ETDEWEB)

    Eichel, G.H.

    1995-12-31

    A detailed description of the conditions and history leading to the establishment and continuity of all-aged mixed coniferous forests in the montane south central region of British Columbia, Canada. Also described are the attempts by one forest products company to perpetuate and proportionally increase this type of forest cover through the selective removal necessitated by bark beetle depredation of the component, Pinus contorta. The report concludes with a description of and recommendations for the post-harvest management employing treatments which imitate natural conditions leading to a gradual and lasting conversion of natural multi-species stands into unevenaged or all-aged stands of mixed conifers which are conducive to single tree or group selection harvests at more or less regular intervals. 10 figs, 1 tab

  17. Analysis of ecological thresholds in a temperate forest undergoing dieback.

    Directory of Open Access Journals (Sweden)

    Philip Martin

    Full Text Available Positive feedbacks in drivers of degradation can cause threshold responses in natural ecosystems. Though threshold responses have received much attention in studies of aquatic ecosystems, they have been neglected in terrestrial systems, such as forests, where the long time-scales required for monitoring have impeded research. In this study we explored the role of positive feedbacks in a temperate forest that has been monitored for 50 years and is undergoing dieback, largely as a result of death of the canopy dominant species (Fagus sylvatica, beech. Statistical analyses showed strong non-linear losses in basal area for some plots, while others showed relatively gradual change. Beech seedling density was positively related to canopy openness, but a similar relationship was not observed for saplings, suggesting a feedback whereby mortality in areas with high canopy openness was elevated. We combined this observation with empirical data on size- and growth-mediated mortality of trees to produce an individual-based model of forest dynamics. We used this model to simulate changes in the structure of the forest over 100 years under scenarios with different juvenile and mature mortality probabilities, as well as a positive feedback between seedling and mature tree mortality. This model produced declines in forest basal area when critical juvenile and mature mortality probabilities were exceeded. Feedbacks in juvenile mortality caused a greater reduction in basal area relative to scenarios with no feedback. Non-linear, concave declines of basal area occurred only when mature tree mortality was 3-5 times higher than rates observed in the field. Our results indicate that the longevity of trees may help to buffer forests against environmental change and that the maintenance of old, large trees may aid the resilience of forest stands. In addition, our work suggests that dieback of forests may be avoidable providing pressures on mature and juvenile trees do

  18. Variation of biomass and carbon pools with forest type in temperate forests of Kashmir Himalaya, India.

    Science.gov (United States)

    Dar, Javid Ahmad; Sundarapandian, Somaiah

    2015-02-01

    An accurate characterization of tree, understory, deadwood, floor litter, and soil organic carbon (SOC) pools in temperate forest ecosystems is important to estimate their contribution to global carbon (C) stocks. However, this information on temperate forests of the Himalayas is lacking and fragmented. In this study, we measured C stocks of tree (aboveground and belowground biomass), understory (shrubs and herbaceous), deadwood (standing and fallen trees and stumps), floor litter, and soil from 111 plots of 50 m × 50 m each, in seven forest types: Populus deltoides (PD), Juglans regia (JR), Cedrus deodara (CD), Pinus wallichiana (PW), mixed coniferous (MC), Abies pindrow (AP), and Betula utilis (BU) in temperate forests of Kashmir Himalaya, India. The main objective of the present study is to quantify the ecosystem C pool in these seven forest types. The results showed that the tree biomass ranged from 100.8 Mg ha(-1) in BU forest to 294.8 Mg ha(-1) for the AP forest. The understory biomass ranged from 0.16 Mg ha(-1) in PD forest to 2.36 Mg ha(-1) in PW forest. Deadwood biomass ranged from 1.5 Mg ha(-1) in PD forest to 14.9 Mg ha(-1) for the AP forest, whereas forest floor litter ranged from 2.5 Mg ha(-1) in BU and JR forests to 3.1 Mg ha(-1) in MC forest. The total ecosystem carbon stocks varied from 112.5 to 205.7 Mg C ha(-1) across all the forest types. The C stocks of tree, understory, deadwood, litter, and soil ranged from 45.4 to 135.6, 0.08 to 1.18, 0.7 to 6.8, 1.1 to 1.4, and 39.1-91.4 Mg ha(-1), respectively, which accounted for 61.3, 0.2, 1.4, 0.8, and 36.3 % of the total carbon stock. BU forest accounted 65 % from soil C and 35 % from biomass, whereas PD forest contributed only 26 % from soil C and 74 % from biomass. Of the total C stock in the 0-30-cm soil, about 55 % was stored in the upper 0-10 cm. Soil C stocks in BU forest were significantly higher than those in other forests. The variability of C pools of different ecosystem components is

  19. Small Sample Sizes Yield Biased Allometric Equations in Temperate Forests

    Science.gov (United States)

    Duncanson, L.; Rourke, O.; Dubayah, R.

    2015-11-01

    Accurate quantification of forest carbon stocks is required for constraining the global carbon cycle and its impacts on climate. The accuracies of forest biomass maps are inherently dependent on the accuracy of the field biomass estimates used to calibrate models, which are generated with allometric equations. Here, we provide a quantitative assessment of the sensitivity of allometric parameters to sample size in temperate forests, focusing on the allometric relationship between tree height and crown radius. We use LiDAR remote sensing to isolate between 10,000 to more than 1,000,000 tree height and crown radius measurements per site in six U.S. forests. We find that fitted allometric parameters are highly sensitive to sample size, producing systematic overestimates of height. We extend our analysis to biomass through the application of empirical relationships from the literature, and show that given the small sample sizes used in common allometric equations for biomass, the average site-level biomass bias is ~+70% with a standard deviation of 71%, ranging from -4% to +193%. These findings underscore the importance of increasing the sample sizes used for allometric equation generation.

  20. Impacts of Mastication: Soil Seed Bank Responses to a Forest Thinning Treatment in Three Colorado (USA Conifer Forest Types

    Directory of Open Access Journals (Sweden)

    Akasha M. Faist

    2015-08-01

    Full Text Available Mastication is a forest fuel thinning treatment that involves chipping or shredding small trees and shrubs and depositing the material across the forest floor. By decreasing forest density mastication has been shown to lessen crown fire hazard, yet other impacts have only recently started to be studied. Our study evaluates how mastication treatments alter the density and composition of soil seed banks in three Colorado conifer forest types. The three forest types were (1 lodgepole pine, (2 ponderosa pine and (3 pinyon pine-juniper. Results showed that masticated sites contained higher seed bank densities than untreated sites: a pattern primarily driven by treatment effects in ponderosa pine forests. The seed bank was dominated by forbs regardless of forest type or treatment. This pattern of forb dominance was not observed in the aboveground vegetation cover as it demonstrated more even proportions of the functional groups. Graminoids showed a higher seed density in treated sites than untreated and, similarly, the identified non-native species only occurred in the treated ponderosa pine sites suggesting a potential belowground invasion for this forest type. These results suggest that presence of masticated material might not be creating a physical barrier hindering the transfer of seeds as predicted.

  1. Seasonality of temperate forest photosynthesis and daytime respiration

    Science.gov (United States)

    Wehr, R.; Munger, J. W.; McManus, J. B.; Nelson, D. D.; Zahniser, M. S.; Davidson, E. A.; Wofsy, S. C.; Saleska, S. R.

    2016-06-01

    Terrestrial ecosystems currently offset one-quarter of anthropogenic carbon dioxide (CO2) emissions because of a slight imbalance between global terrestrial photosynthesis and respiration. Understanding what controls these two biological fluxes is therefore crucial to predicting climate change. Yet there is no way of directly measuring the photosynthesis or daytime respiration of a whole ecosystem of interacting organisms; instead, these fluxes are generally inferred from measurements of net ecosystem-atmosphere CO2 exchange (NEE), in a way that is based on assumed ecosystem-scale responses to the environment. The consequent view of temperate deciduous forests (an important CO2 sink) is that, first, ecosystem respiration is greater during the day than at night; and second, ecosystem photosynthetic light-use efficiency peaks after leaf expansion in spring and then declines, presumably because of leaf ageing or water stress. This view has underlain the development of terrestrial biosphere models used in climate prediction and of remote sensing indices of global biosphere productivity. Here, we use new isotopic instrumentation to determine ecosystem photosynthesis and daytime respiration in a temperate deciduous forest over a three-year period. We find that ecosystem respiration is lower during the day than at night—the first robust evidence of the inhibition of leaf respiration by light at the ecosystem scale. Because they do not capture this effect, standard approaches overestimate ecosystem photosynthesis and daytime respiration in the first half of the growing season at our site, and inaccurately portray ecosystem photosynthetic light-use efficiency. These findings revise our understanding of forest-atmosphere carbon exchange, and provide a basis for investigating how leaf-level physiological dynamics manifest at the canopy scale in other ecosystems.

  2. Changes to the N cycle following bark beetle outbreaks in two contrasting conifer forest types.

    Science.gov (United States)

    Griffin, Jacob M; Turner, Monica G

    2012-10-01

    Outbreaks of Dendroctonus beetles are causing extensive mortality in conifer forests throughout North America. However, nitrogen (N) cycling impacts among forest types are not well known. We quantified beetle-induced changes in forest structure, soil temperature, and N cycling in Douglas-fir (Pseudotsuga menziesii) forests of Greater Yellowstone (WY, USA), and compared them to published lodgepole pine (Pinus contorta var. latifolia) data. Five undisturbed stands were compared to five beetle-killed stands (4-5 years post-outbreak). We hypothesized greater N cycling responses in Douglas-fir due to higher overall N stocks. Undisturbed Douglas-fir stands had greater litter N pools, soil N, and net N mineralization than lodgepole pine. Several responses to disturbance were similar between forest types, including a pulse of N-enriched litter, doubling of soil N availability, 30-50 % increase in understory cover, and 20 % increase in foliar N concentration of unattacked trees. However, the response of some ecosystem properties notably varied by host forest type. Soil temperature was unaffected in Douglas-fir, but lowered in lodgepole pine. Fresh foliar %N was uncorrelated with net N mineralization in Douglas-fir, but positively correlated in lodgepole pine. Though soil ammonium and nitrate, net N mineralization, and net nitrification all doubled, they remained low in both forest types (mineralization; litter and soil N cycling similarly in each forest type, despite substantial differences in pre-disturbance biogeochemistry. In contrast, soil temperature and soil N-foliar N linkages differed between host forest types. This result suggests that disturbance type may be a better predictor of litter and soil N responses than forest type due to similar disturbance mechanisms and disturbance legacies across both host-beetle systems.

  3. Biophysical controls on soil respiration in the dominant patch types of an old-growth, mixed-conifer forest

    Science.gov (United States)

    Siyan Ma; Jiquan Chen; John R. Butnor; Malcolm North; Eugénie S. Euskirchen; Brian Oakley

    2005-01-01

    Little is known about biophysical controls on soil respiration in California's Sierra Nevada old-growth, mixed-conifer forests. Using portable and automated soil respiration sampling units, we measured soil respiration rate (SRR) in three dominant patch types: closed canopy (CC), ceanothus-dominated patches (CECO), and open canopy (OC). SRR varied significantly...

  4. A fuel treatment reduces potential fire severity and increases suppression efficiency in a Sierran mixed conifer forest

    Science.gov (United States)

    Jason J. Moghaddas

    2006-01-01

    Fuel treatments are being widely implemented on public and private lands across the western U.S. While scientists and managers have an understanding of how fuel treatments can modify potential fire behavior under modeled conditions, there is limited information on how treatments perform under real wildfire conditions in Sierran mixed conifer forests. The Bell Fire...

  5. Effects of fire and harvest on soil respiration in a mixed-conifer forest

    Science.gov (United States)

    Dore, S.; Fry, D.; Stephens, S.

    2012-12-01

    Forest ecosystems, and in particular forest soils, constitute a major reservoir of global terrestrial carbon and soil respiration is the largest carbon loss from these ecosystems. Disturbances can affect soil respiration, causing physical and chemical changes in soil characteristics, adding both, above and belowground necromass, and changing microclimatic conditions. This could signify an important and long term carbon loss, even higher than the carbon directly removed by the harvest or during fire. These losses need to be included when quantifying the net carbon balance of forests. We measured the impacts of prescribed fire and clear-cut tree harvest on soil respiration in a mixed-conifer forest in the central Sierra Nevada. The prescribed fire treatment was implemented in 2002 and again in 2009. Four areas were clear-cut harvested in 2010. In half of these units the soils were mechanically ripped to reduce soil compaction, a common practice in the Sierra Nevada industrial forest lands. Soil respiration was measured using two different techniques: the chamber method and the gradient method. Soil respiration was affected by treatments in two different ways. First, treatments changed soil temperature and soil water content, the main abiotic factors controlling soil respiration. The clear cut and the prescribed fire treatments created higher maximum soil temperature and more available soil water content, environmental conditions favorable to soil respiration. However, the loss of trees and thus fine roots, and the decrease of soil litter and organic layers, because of their combustion or removal, had a negative effect on soil respiration that was stronger than the positive effect due to more favorable post disturbance environmental conditions. Soil respiration rates remained steady 1-2 years after treatments and no increase or spikes of soil respiration were measured after treatments. Continuous measurements of CO2 concentrations at different soil depths improved our

  6. Coarse-scale population structure of pathogenic Armillaria species in a mixed-conifer forest in the Blue Mountains of northeast Oregon.

    Science.gov (United States)

    B.A. Ferguson; T.A. Dreisbach; C.G. Parks; G.M. Filip; C.L. Schmitt

    2003-01-01

    The coarse-scale population structure of pathogenic Armillaria (Fr.) Staude species was determined on approximately 16 100 ha Of relatively dry, mixed-conifer forest in the Blue Mountains of northeast Oregon. Sampling of recently dead or live, symptomatic conifers produced 112 isolates of Armillaria from six tree species.

  7. Organic and inorganic nitrogen uptake by 21 dominant tree species in temperate and tropical forests.

    Science.gov (United States)

    Liu, Min; Li, Changcheng; Xu, Xingliang; Wanek, Wolfgang; Jiang, Ning; Wang, Huimin; Yang, Xiaodong

    2017-11-01

    Evidence shows that many tree species can take up organic nitrogen (N) in the form of free amino acids from soils, but few studies have been conducted to compare organic and inorganic N uptake patterns in temperate and tropical tree species in relation to mycorrhizal status and successional state. We labeled intact tree roots by brief 15N exposures using field hydroponic experiments in a temperate forest and a tropical forest in China. A total of 21 dominant tree species were investigated, 8 in the temperate forest and 13 in the tropical forest. All investigated tree species showed highest uptake rates for NH4+ (ammonium), followed by glycine and NO3- (nitrate). Uptake of NH4+ by temperate trees averaged 12.8 μg N g-1 dry weight (d.w.) root h-1, while those by tropical trees averaged 6.8 μg N g-1 d.w. root h-1. Glycine uptake rates averaged 3.1 μg N g-1 d.w. root h-1 for temperate trees and 2.4 μg N g-1 d.w. root h-1 for tropical trees. NO3- uptake was the lowest (averaging 0.8 μg N g-1 d.w. root h-1 for temperate trees and 1.2 μg N g-1 d.w. root h-1 for tropical trees). Uptake of NH4+ accounted for 76% of the total uptake of all three N forms in the temperate forest and 64% in the tropical forest. Temperate tree species had similar glycine uptake rates as tropical trees, with the contribution being slightly lower (20% in the temperate forest and 23% in the tropical forest). All tree species investigated in the temperate forest were ectomycorrhizal and all species but one in the tropical forest were arbuscular mycorrhizal (AM). Ectomycorrhizal trees showed significantly higher NH4+ and lower NO3- uptake rates than AM trees. Mycorrhizal colonization rates significantly affected uptake rates and contributions of NO3- or NH4+, but depended on forest types. We conclude that tree species in both temperate and tropical forests preferred to take up NH4+, with organic N as the second most important N source. These findings suggest that temperate and tropical forests

  8. The changing role of fire in conifer-dominated temperate rainforest through the last 14,000 years

    Science.gov (United States)

    Fletcher, M.-S.; Bowman, D. M. J. S.; Whitlock, C.; Mariani, M.; Stahle, L.

    2018-02-01

    Climate, fire and vegetation dynamics are often tightly coupled through time. Here, we use a 14 kyr sedimentary charcoal and pollen record from Lake Osborne, Tasmania, Australia, to explore how this relationship changes under varying climatic regimes within a temperate rainforest ecosystem. Superposed epoch analysis reveals a significant relationship between fire and vegetation change throughout the Holocene at our site. Our data indicates an initial resilience of the rainforest system to fire under a stable cool and humid climate regime between ca. 12-6 ka. In contrast, fires that occurred after 6 ka, under an increasingly variable climate regime wrought by the onset of the El Niño-Southern Oscillation (ENSO), resulted in a series of changes within the local rainforest vegetation that culminated in the replacement of rainforest by fire-promoted Eucalypt forest. We suggest that an increasingly variable ENSO-influenced climate regime inhibited rainforest recovery from fire because of slower growth, reduced fecundity and increased fire frequency, thus contributing to the eventual collapse of the rainforest system.

  9. Radiation budget changes with dry forest clearing in temperate Argentina.

    Science.gov (United States)

    Houspanossian, Javier; Nosetto, Marcelo; Jobbágy, Esteban G

    2013-04-01

    Land cover changes may affect climate and the energy balance of the Earth through their influence on the greenhouse gas composition of the atmosphere (biogeochemical effects) but also through shifts in the physical properties of the land surface (biophysical effects). We explored how the radiation budget changes following the replacement of temperate dry forests by crops in central semiarid Argentina and quantified the biophysical radiative forcing of this transformation. For this purpose, we computed the albedo and surface temperature for a 7-year period (2003-2009) from MODIS imagery at 70 paired sites occupied by native forests and crops and calculated the radiation budget at the tropopause and surface levels using a columnar radiation model parameterized with satellite data. Mean annual black-sky albedo and diurnal surface temperature were 50% and 2.5 °C higher in croplands than in dry forests. These contrasts increased the outgoing shortwave energy flux at the top of the atmosphere in croplands by a quarter (58.4 vs. 45.9 W m(-2) ) which, together with a slight increase in the outgoing longwave flux, yielded a net cooling of -14 W m(-2) . This biophysical cooling effect would be equivalent to a reduction in atmospheric CO2 of 22 Mg C ha(-1) , which involves approximately a quarter to a half of the typical carbon emissions that accompany deforestation in these ecosystems. We showed that the replacement of dry forests by crops in central Argentina has strong biophysical effects on the energy budget which could counterbalance the biogeochemical effects of deforestation. Underestimating or ignoring these biophysical consequences of land-use changes on climate will certainly curtail the effectiveness of many warming mitigation actions, particularly in semiarid regions where high radiation load and smaller active carbon pools would increase the relative importance of biophysical forcing. © 2012 Blackwell Publishing Ltd.

  10. Forest thinning impacts on the water balance of Sierra Nevada mixed-conifer headwater basins

    Science.gov (United States)

    Saksa, P. C.; Conklin, M. H.; Battles, J. J.; Tague, C. L.; Bales, R. C.

    2017-07-01

    Headwater catchments in the mixed-conifer zone of the American and Merced River basins were selectively thinned in 2012 to reduce the risk of high-intensity wildfire. Distributed observations of forest vegetation thinning, precipitation, snowpack storage, soil water storage, energy balance, and stream discharge from 2010 to 2013 were used to calculate the water balance and constrain a hydroecologic model. Using the spatially calibrated RHESSys model, we assessed thinning effects on the water balance. In the central-Sierra American River headwaters, there was a mean-annual runoff increase of 14% in response to the observed thinning patterns, which included heterogeneous reductions in leaf area index (-8%), canopy cover (-3%), and shrub cover (-4%). In the southern-Sierra Merced River headwaters, thinning had little impact on forest structure or runoff, as vegetation growth in areas not thinned offset reductions from thinning. Observed thinning effects on runoff could not be confirmed in either basin by measurements alone, in part because of the high variability in precipitation during the measurement period. Modeling results show that when thinning is intensive enough to change forest structure, low-magnitude vegetation reductions have greater potential to modify the catchment-scale water balance in the higher-precipitation central Sierra Nevada versus in the more water-limited southern Sierra Nevada. Hydrologic modeling, constrained by detailed, multiyear field measurements, provides a useful tool for analyzing catchment response to forest thinning.

  11. Temperature sensitivity and basal rate of soil respiration and their determinants in temperate forests of North China.

    Science.gov (United States)

    Zhou, Zhiyong; Guo, Chao; Meng, He

    2013-01-01

    The basal respiration rate at 10°C (R10) and the temperature sensitivity of soil respiration (Q10) are two premier parameters in predicting the instantaneous rate of soil respiration at a given temperature. However, the mechanisms underlying the spatial variations in R10 and Q10 are not quite clear. R10 and Q10 were calculated using an exponential function with measured soil respiration and soil temperature for 11 mixed conifer-broadleaved forest stands and nine broadleaved forest stands at a catchment scale. The mean values of R10 were 1.83 µmol CO2 m(-2) s(-1) and 2.01 µmol CO2 m(-2) s(-1), the mean values of Q10 were 3.40 and 3.79, respectively, for mixed and broadleaved forest types. Forest type did not influence the two model parameters, but determinants of R10 and Q10 varied between the two forest types. In mixed forest stands, R10 decreased greatly with the ratio of coniferous to broadleaved tree species; whereas it sharply increased with the soil temperature range and the variations in soil organic carbon (SOC), and soil total nitrogen (TN). Q10 was positively correlated with the spatial variances of herb-layer carbon stock and soil bulk density, and negatively with soil C/N ratio. In broadleaved forest stands, R10 was markedly affected by basal area and the variations in shrub carbon stock and soil phosphorus (P) content; the value of Q10 largely depended on soil pH and the variations of SOC and TN. 51% of variations in both R10 and Q10 can be accounted for jointly by five biophysical variables, of which the variation in soil bulk density played an overwhelming role in determining the amplitude of variations in soil basal respiration rates in temperate forests. Overall, it was concluded that soil respiration of temperate forests was largely dependent on soil physical properties when temperature kept quite low.

  12. Trends in Snag Populations in Drought-Stressed Mixed-Conifer and Ponderosa Pine Forests (1997–2007

    Directory of Open Access Journals (Sweden)

    Joseph L. Ganey

    2012-01-01

    Full Text Available Snags provide important biological legacies, resources for numerous species of native wildlife, and contribute to decay dynamics and ecological processes in forested ecosystems. We monitored trends in snag populations from 1997 to 2007 in drought-stressed mixed-conifer and ponderosa pine (Pinus ponderosa Dougl. ex Laws forests, northern Arizona. Median snag density increased by 75 and 90% in mixed-conifer and ponderosa pine forests, respectively, over this time period. Increased snag density was driven primarily by a large pulse in drought-mediated tree mortality from 2002 to 2007, following a smaller pulse from 1997 to 2002. Decay-class composition and size-class composition of snag populations changed in both forest types, and species composition changed in mixed-conifer forest. Increases in snag abundance may benefit some species of native wildlife in the short-term by providing increased foraging and nesting resources, but these increases may be unsustainable in the long term. Observed changes in snag recruitment and fall rates during the study illustrate the difficulty involved in modeling dynamics of those populations in an era of climate change and changing land management practices.

  13. RECONSTRUCTING THE EVOLUTIONARY HISTORY OF THE FOREST FUNGAL PATHOGEN, ARMILLARIA MELLEA, IN A TEMPERATE WORLDWIDE POPULATIONS

    Science.gov (United States)

    The forest pathogen Armillaria mellea s.s. (Basidiomycota, Physalacriaceae) is among the most significant forest pathogens causing root rot in northern temperate forest trees worldwide. Phylogenetic reconstructions for A. mellea show distinct European, Asian and North American lineages. The North Am...

  14. Arthropod vertical stratification in temperate deciduous forests: Implications for conservation oriented management

    Science.gov (United States)

    Ulyshen Michael

    2011-01-01

    Studies on the vertical distribution patterns of arthropods in temperate deciduous forests reveal highly stratified (i.e., unevenly vertically distributed) communities. These patterns are determined by multiple factors acting simultaneously, including: (1) time (forest age, season, time of day); (2) forest structure (height, vertical foliage complexity, plant surface...

  15. Snowmelt timing, phenology, and growing season length in conifer forests of Crater Lake National Park, USA

    Science.gov (United States)

    O'Leary, Donal S.; Kellermann, Jherime L.; Wayne, Chris

    2018-02-01

    Anthropogenic climate change is having significant impacts on montane and high-elevation areas globally. Warmer winter temperatures are driving reduced snowpack in the western USA with broad potential impacts on ecosystem dynamics of particular concern for protected areas. Vegetation phenology is a sensitive indicator of ecological response to climate change and is associated with snowmelt timing. Human monitoring of climate impacts can be resource prohibitive for land management agencies, whereas remotely sensed phenology observations are freely available at a range of spatiotemporal scales. Little work has been done in regions dominated by evergreen conifer cover, which represents many mountain regions at temperate latitudes. We used moderate resolution imaging spectroradiometer (MODIS) data to assess the influence of snowmelt timing and elevation on five phenology metrics (green up, maximum greenness, senescence, dormancy, and growing season length) within Crater Lake National Park, Oregon, USA from 2001 to 2012. Earlier annual mean snowmelt timing was significantly correlated with earlier onset of green up at the landscape scale. Snowmelt timing and elevation have significant explanatory power for phenology, though with high variability. Elevation has a moderate control on early season indicators such as snowmelt timing and green up and less on late-season variables such as senescence and growing season length. PCA results show that early season indicators and late season indicators vary independently. These results have important implications for ecosystem dynamics, management, and conservation, particularly of species such as whitebark pine ( Pinus albicaulis) in alpine and subalpine areas.

  16. Snowmelt timing, phenology, and growing season length in conifer forests of Crater Lake National Park, USA.

    Science.gov (United States)

    O'Leary, Donal S; Kellermann, Jherime L; Wayne, Chris

    2018-02-01

    Anthropogenic climate change is having significant impacts on montane and high-elevation areas globally. Warmer winter temperatures are driving reduced snowpack in the western USA with broad potential impacts on ecosystem dynamics of particular concern for protected areas. Vegetation phenology is a sensitive indicator of ecological response to climate change and is associated with snowmelt timing. Human monitoring of climate impacts can be resource prohibitive for land management agencies, whereas remotely sensed phenology observations are freely available at a range of spatiotemporal scales. Little work has been done in regions dominated by evergreen conifer cover, which represents many mountain regions at temperate latitudes. We used moderate resolution imaging spectroradiometer (MODIS) data to assess the influence of snowmelt timing and elevation on five phenology metrics (green up, maximum greenness, senescence, dormancy, and growing season length) within Crater Lake National Park, Oregon, USA from 2001 to 2012. Earlier annual mean snowmelt timing was significantly correlated with earlier onset of green up at the landscape scale. Snowmelt timing and elevation have significant explanatory power for phenology, though with high variability. Elevation has a moderate control on early season indicators such as snowmelt timing and green up and less on late-season variables such as senescence and growing season length. PCA results show that early season indicators and late season indicators vary independently. These results have important implications for ecosystem dynamics, management, and conservation, particularly of species such as whitebark pine (Pinus albicaulis) in alpine and subalpine areas.

  17. Species composition and forest structure explain the temperature sensitivity patterns of productivity in temperate forests

    Science.gov (United States)

    Bohn, Friedrich J.; May, Felix; Huth, Andreas

    2018-03-01

    Rising temperatures due to climate change influence the wood production of forests. Observations show that some temperate forests increase their productivity, whereas others reduce their productivity. This study focuses on how species composition and forest structure properties influence the temperature sensitivity of aboveground wood production (AWP). It further investigates which forests will increase their productivity the most with rising temperatures. We described forest structure by leaf area index, forest height and tree height heterogeneity. Species composition was described by a functional diversity index (Rao's Q) and a species distribution index (ΩAWP). ΩAWP quantified how well species are distributed over the different forest layers with regard to AWP. We analysed 370 170 forest stands generated with a forest gap model. These forest stands covered a wide range of possible forest types. For each stand, we estimated annual aboveground wood production and performed a climate sensitivity analysis based on 320 different climate time series (of 1-year length). The scenarios differed in mean annual temperature and annual temperature amplitude. Temperature sensitivity of wood production was quantified as the relative change in productivity resulting from a 1 °C rise in mean annual temperature or annual temperature amplitude. Increasing ΩAWP positively influenced both temperature sensitivity indices of forest, whereas forest height showed a bell-shaped relationship with both indices. Further, we found forests in each successional stage that are positively affected by temperature rise. For such forests, large ΩAWP values were important. In the case of young forests, low functional diversity and small tree height heterogeneity were associated with a positive effect of temperature on wood production. During later successional stages, higher species diversity and larger tree height heterogeneity were an advantage. To achieve such a development, one could plant

  18. [Effects of artificial Ulmus pumila forest on plant diversity of temperate grassland in Inner Mongolia].

    Science.gov (United States)

    Yang, Hong-Xiao; Wang, Xue-Quan; Yang, Wen-Bin; Lu, Qi

    2008-06-01

    Based on field survey, the effects of artificial Ulmus pumila forest on the species diversity of temperate grassland in Siziwang Banner of Inner Mongolia were studied. The results showed that U. pumila forest had obvious effects on the species diversity of grassland. With increasing density of U. pumila, the Patrick's richness, Pielou's evenness and Shannon-Wiener index of grass species under the forest had a decreasing trend, and were higher nearby the forest than far from the forest. The habitat inside the forest was favorable to Silene jenisseensis, while that nearby the forest was favorable to Heteropappus altaicus, Pocockia ruthenia, Potentilla bifurca, Leymus secalinus and Cleistogenes squarrosa, suggesting that to blindly exclude forestation on grassland could be less scientific, while properly afforesting U. pumila on the sides with relatively abundant soil moisture should be available to the conservation of plant diversity in temperate grassland regions.

  19. Litter dynamics in two Sierran mixed conifer forests. I. Litterfall and decomposition rates

    Science.gov (United States)

    Stohlgren, Thomas J.

    1988-01-01

    Litterfall was measured for 4 years and leaf litter decomposition rates were studied for 3.6 years in two mixed conifer forest (giant sequoia-fir and fir-pine) in the southern Sierra Nevada of California. The giant sequoia-fir forest (GS site) was dominated by giant sequoia (Sequoiadendron giganteum (Lindl.) Buchh.), white fir (Abies concolor Lindl. & Gord.), and sugar pine (Pinus lambertiana Dougl.). The fir-pine forest (FP site) was dominated by white fir, sugar pine, and incense cedar (Calocedrus decurrens (Torr.) Florin). Litterfall, including large woody debris -1•year-1 compared with 4355 kg•ha-1•year-1 at the FP site (3.4:1). In the GS site, leaf litter decomposition after 3.6 years was slowest for giant sequoia (28.2% mass loss), followed by sugar pine (34.3%) and white fie (45.1%). In the FP site, mass loss was slowest for sugar pine (40.0%), followed by white fir (45.1%), while incense cedar showed the greatest mass loss (56.9%) after 3.6 years. High litterfall rates of large woody debris (i.e., 2.5-15.2 cm diameter) and slow rates of leaf litter decomposition in the giant sequoia-fir forest type may result in higher litter accumulation rates than in the fir-pine type. Leaf litter times to 95% decay for the GS and FP sites were 30 and 27 years, respectively, if the initial 0.7-year period (a short period of rapid mass decay) was ignored in the calculation. A mass balance approach for total litterfall (<15.2 cm diameter) decomposition yielded lower decay constants than did the litterbag study and therefore longer times to 95% decay (57 years for the GS site and 62 years for the FP site).

  20. Management Impacts on Carbon Dynamics in a Sierra Nevada Mixed Conifer Forest.

    Science.gov (United States)

    Dore, Sabina; Fry, Danny L; Collins, Brandon M; Vargas, Rodrigo; York, Robert A; Stephens, Scott L

    2016-01-01

    Forest ecosystems can act as sinks of carbon and thus mitigate anthropogenic carbon emissions. When forests are actively managed, treatments can alter forests carbon dynamics, reducing their sink strength and switching them from sinks to sources of carbon. These effects are generally characterized by fast temporal dynamics. Hence this study monitored for over a decade the impacts of management practices commonly used to reduce fire hazards on the carbon dynamics of mixed-conifer forests in the Sierra Nevada, California, USA. Soil CO2 efflux, carbon pools (i.e. soil carbon, litter, fine roots, tree biomass), and radial tree growth were compared among un-manipulated controls, prescribed fire, thinning, thinning followed by fire, and two clear-cut harvested sites. Soil CO2 efflux was reduced by both fire and harvesting (ca. 15%). Soil carbon content (upper 15 cm) was not significantly changed by harvest or fire treatments. Fine root biomass was reduced by clear-cut harvest (60-70%) but not by fire, and the litter layer was reduced 80% by clear-cut harvest and 40% by fire. Thinning effects on tree growth and biomass were concentrated in the first year after treatments, whereas fire effects persisted over the seven-year post-treatment period. Over this period, tree radial growth was increased (25%) by thinning and reduced (12%) by fire. After seven years, tree biomass returned to pre-treatment levels in both fire and thinning treatments; however, biomass and productivity decreased 30%-40% compared to controls when thinning was combined with fire. The clear-cut treatment had the strongest impact, reducing ecosystem carbon stocks and delaying the capacity for carbon uptake. We conclude that post-treatment carbon dynamics and ecosystem recovery time varied with intensity and type of treatments. Consequently, management practices can be selected to minimize ecosystem carbon losses while increasing future carbon uptake, resilience to high severity fire, and climate related

  1. Contrasting patterns of nucleotide diversity for four conifers of Alpine European forests.

    Science.gov (United States)

    Mosca, Elena; Eckert, Andrew J; Liechty, John D; Wegrzyn, Jill L; La Porta, Nicola; Vendramin, Giovanni G; Neale, David B

    2012-11-01

    A candidate gene approach was used to identify levels of nucleotide diversity and to identify genes departing from neutral expectations in coniferous species of the Alpine European forest. Twelve samples were collected from four species that dominate montane and subalpine forests throughout Europe: Abies alba Mill, Larix decidua Mill, Pinus cembra L., and Pinus mugo Turra. A total of 800 genes, originally resequenced in Pinus taeda L., were resequenced across 12 independent trees for each of the four species. Genes were assigned to two categories, candidate and control, defined through homology-based searches to Arabidopsis. Estimates of nucleotide diversity per site varied greatly between polymorphic candidate genes (range: 0.0004-0.1295) and among species (range: 0.0024-0.0082), but were within the previously established ranges for conifers. Tests of neutrality using stringent significance thresholds, performed under the standard neutral model, revealed one to seven outlier loci for each species. Some of these outliers encode proteins that are involved with plant stress responses and form the basis for further evolutionary enquiries.

  2. Contrasting patterns of nucleotide diversity for four conifers of Alpine European forests

    Science.gov (United States)

    Mosca, Elena; Eckert, Andrew J; Liechty, John D; Wegrzyn, Jill L; La Porta, Nicola; Vendramin, Giovanni G; Neale, David B

    2012-01-01

    A candidate gene approach was used to identify levels of nucleotide diversity and to identify genes departing from neutral expectations in coniferous species of the Alpine European forest. Twelve samples were collected from four species that dominate montane and subalpine forests throughout Europe: Abies alba Mill, Larix decidua Mill, Pinus cembra L., and Pinus mugo Turra. A total of 800 genes, originally resequenced in Pinus taeda L., were resequenced across 12 independent trees for each of the four species. Genes were assigned to two categories, candidate and control, defined through homology-based searches to Arabidopsis. Estimates of nucleotide diversity per site varied greatly between polymorphic candidate genes (range: 0.0004–0.1295) and among species (range: 0.0024–0.0082), but were within the previously established ranges for conifers. Tests of neutrality using stringent significance thresholds, performed under the standard neutral model, revealed one to seven outlier loci for each species. Some of these outliers encode proteins that are involved with plant stress responses and form the basis for further evolutionary enquiries. PMID:23144662

  3. Long-Term fire effect on some chemical parameters and microbial diversity in a conifer forest soil

    International Nuclear Information System (INIS)

    Iglesias, T.; Iglesias, M.; Ramirez, M.; Fernandez-Bermejo, M. C.

    2009-01-01

    Soil micro biota are one of the soil components most affected by wildfires. The data from the present study were obtained from a conifer forest soil at Sierra de Gredos (Avila, central Spain) twenty years after fire of low-to-moderate intensity. A set of soil characteristics indicated the extent to which the spontaneous recovery of the soil is produced as a result of vegetation regrowth. (Author)

  4. Simulating phenological shifts in French temperate forests under two climatic change scenarios and four driving global circulation models

    Science.gov (United States)

    Lebourgeois, François; Pierrat, Jean-Claude; Perez, Vincent; Piedallu, Christian; Cecchini, Sébastien; Ulrich, Erwin

    2010-09-01

    After modeling the large-scale climate response patterns of leaf unfolding, leaf coloring and growing season length of evergreen and deciduous French temperate trees, we predicted the effects of eight future climate scenarios on phenological events. We used the ground observations from 103 temperate forests (10 species and 3,708 trees) from the French Renecofor Network and for the period 1997-2006. We applied RandomForest algorithms to predict phenological events from climatic and ecological variables. With the resulting models, we drew maps of phenological events throughout France under present climate and under two climatic change scenarios (A2, B2) and four global circulation models (HadCM3, CGCM2, CSIRO2 and PCM). We compared current observations and predicted values for the periods 2041-2070 and 2071-2100. On average, spring development of oaks precedes that of beech, which precedes that of conifers. Annual cycles in budburst and leaf coloring are highly correlated with January, March-April and October-November weather conditions through temperature, global solar radiation or potential evapotranspiration depending on species. At the end of the twenty-first century, each model predicts earlier budburst (mean: 7 days) and later leaf coloring (mean: 13 days) leading to an average increase in the growing season of about 20 days (for oaks and beech stands). The A2-HadCM3 hypothesis leads to an increase of up to 30 days in many areas. As a consequence of higher predicted warming during autumn than during winter or spring, shifts in leaf coloring dates appear greater than trends in leaf unfolding. At a regional scale, highly differing climatic response patterns were observed.

  5. Edge effects enhance carbon uptake and its vulnerability to climate change in temperate broadleaf forests.

    Science.gov (United States)

    Reinmann, Andrew B; Hutyra, Lucy R

    2017-01-03

    Forest fragmentation is a ubiquitous, ongoing global phenomenon with profound impacts on the growing conditions of the world's remaining forest. The temperate broadleaf forest makes a large contribution to the global terrestrial carbon sink but is also the most heavily fragmented forest biome in the world. We use field measurements and geospatial analyses to characterize carbon dynamics in temperate broadleaf forest fragments. We show that forest growth and biomass increase by 89 ± 17% and 64 ± 12%, respectively, from the forest interior to edge, but ecosystem edge enhancements are not currently captured by models or approaches to quantifying regional C balance. To the extent that the findings from our research represent the forest of southern New England in the United States, we provide a preliminary estimate that edge growth enhancement could increase estimates of the region's carbon uptake and storage by 13 ± 3% and 10 ± 1%, respectively. However, we also find that forest growth near the edge declines three times faster than that in the interior in response to heat stress during the growing season. Using climate projections, we show that future heat stress could reduce the forest edge growth enhancement by one-third by the end of the century. These findings contrast studies of edge effects in the world's other major forest biomes and indicate that the strength of the temperate broadleaf forest carbon sink and its capacity to mitigate anthropogenic carbon emissions may be stronger, but also more sensitive to climate change than previous estimates suggest.

  6. Comparative Structural Dynamics of the Janj Mixed Old-Growth Mountain Forest in Bosnia and Herzegovina: Are Conifers in a Long-Term Decline?

    Directory of Open Access Journals (Sweden)

    Srdjan Keren

    2014-06-01

    Full Text Available Regression of conifers in European mixed old-growth mountain forests has been observed for a long period and studied from different aspects. Old-growth (OG forests in Bosnia and Herzegovina (BiH have not experienced heavy air pollution and chronic overbrowsing that have affected many other European OG forests, while climatic and anthropogenic disturbances have been well documented. We analysed stand structure in the Janj OG forest, compared it with inventories of Lom and Perucica OG forests (BiH and with earlier inventories of the same reserves. At present, OG forest Janj is characterized by a high growing stock (1215 m3∙ha−1. This is due to good site quality, prevalence of conifers (84% and dominant endogenous processes in recent decades. In all three OG forests, indicators of structural change exhibited progression of European beech over time. Historical evidence revealed the occurrence of warm summers and droughts followed by bark beetle outbreaks in the 1920s, 1940s and early 1950s, which in turn influenced a marked conifer decline. It seems likely that repeated canopy opening released waves of European beech regeneration. These stand structural changes have delayed the rejuvenation of conifers and can help explain the early observations of conifer decline.

  7. Litter dynamics in two Sierran mixed conifer forests. II. Nutrient release in decomposing leaf litter

    Science.gov (United States)

    Stohlgren, Thomas J.

    1988-01-01

    The factors influencing leaf litter decomposition and nutrient release patterns were investigated for 3.6 years in two mixed conifer forests in the southern Sierra Nevada of California. The giant sequoia–fir forest was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Initial concentrations of nutrients and percent lignin, cellulose, and acid detergent fiber vary considerably in freshly abscised leaf litter of the studied species. Giant sequoia had the highest concentration of lignin (20.3%) and the lowest concentration of nitrogen (0.52%), while incense cedar had the lowest concentration of lignin (9.6%) and second lowest concentration of nitrogen (0.63%). Long-term (3.6 years) foliage decomposition rates were best correlated with initial lignin/N (r2 = 0.94, p r2 = 0.92, p r2 = 0.80, p < 0.05). Patterns of nutrient release were highly variable. Giant sequoia immobilized N and P, incense cedar immobilized N and to a lesser extent P, while sugar pine immobilized Ca. Strong linear or negative exponential relationships existed between initial concentrations of N, P, K, and Ca and percent original mass remaining of those nutrients after 3.6 years. This suggests efficient retention of these nutrients in the litter layer of these ecosystems. Nitrogen concentrations steadily increase in decomposing leaf litter, effectively reducing the C/N ratios from an initial range of 68–96 to 27–45 after 3.6 years.

  8. Mechanisms of nitrogen deposition effects on temperate forest lichens and trees

    Science.gov (United States)

    Therese S. Carter; Christopher M. Clark; Mark E. Fenn; Sarah Jovan; Steven S. Perakis; Jennifer Riddell; Paul G. Schaberg; Tara L. Greaver; Meredith G. Hastings

    2017-01-01

    We review the mechanisms of deleterious nitrogen (N) deposition impacts on temperate forests, with a particular focus on trees and lichens. Elevated anthropogenic N deposition to forests has varied effects on individual organisms depending on characteristics both of the N inputs (form, timing, amount) and of the organisms (ecology, physiology) involved. Improved...

  9. Suitability of close-to-nature silviculture for adapting temperate European forests to climate change

    NARCIS (Netherlands)

    Brang, P.; Spathelf, P.; Larsen, J.B.; Bauhus, J.; Boncina, A.; Mohren, G.M.J.

    2014-01-01

    In many parts of Europe, close-to-nature silviculture (CNS) has been widely advocated as being the best approach for managing forests to cope with future climate change. In this review, we identify and evaluate six principles for enhancing the adaptive capacity of European temperate forests in a

  10. Riparian forest as a management tool for moderating future thermal conditions of lowland temperate streams

    NARCIS (Netherlands)

    Kristensen, P.B.; Kristensen, E.A.; Riis, T.; Baisner, A.J.; Larsen, S.E.; Verdonschot, P.F.M.; Baattrup-Pedersen, A.

    2013-01-01

    Predictions of the future climate infer that stream water temperatures may increase in temperate lowland areas and that streams without riparian forest will be particularly prone to elevated stream water temperature. Planting of riparian forest is a potential mitigation measure to reduce water

  11. Life on the edge: carbon fluxes from wetland to ocean along Alaska's coastal temperate rain forest

    Science.gov (United States)

    Rhonda Mazza; Richard Edwards; David D' Amore

    2010-01-01

    Acre for acre, streams of the coastal temperate rain forest along the Gulf of Alaska export 36 times as much dissolved organic carbon as the world average. Rain and snow are the great connectors, tightly linking aquatic and terrestrial systems of this region. The freshwater that flushes over and through the forest floor leaches carbon...

  12. Detrimental Influence of Invasive Earthworms on North American Cold-Temperate Forest Soils

    Science.gov (United States)

    Enerson, Isabel

    2012-01-01

    The topic of invasive earthworms is a timely concern that goes against many preconceived notions regarding the positive benefits of all worms. In the cold-temperate forests of North America invasive worms are threatening forest ecosystems, due to the changes they create in the soil, including decreases in C:N ratios and leaf litter, disruption of…

  13. Relationships between Tropical, Temperate and Boreal Forest Variables and PALSAR Data

    Science.gov (United States)

    Tansey, Kevin; Balzter, Heiko; Hoscilo, Agata; Luckman, Adrian; Page, Susan E.

    2008-11-01

    The overall aim of our ALOS project is to evaluate the information content of polarimetric radar data sets, being acquired by the PALSAR instrument, to estimate forest variables (specifically those related to biomass and biomass change) of forested regions in the UK (temperate forest), central Siberia (boreal forest) and Indonesia (tropical forest in Sumatra and Borneo). By utilising the FBD and PLR operating modes of PALSAR, as well as interferometric products derived from 46-day repeat-pass data, we explore the relationships between measured bio-physical forest variables (from field data) with values of backscatter coefficient, coherence and other data derived values. The paper will show our initial observations and interpretations.

  14. Uncertainty of Forest Biomass Estimates in North Temperate Forests Due to Allometry: Implications for Remote Sensing

    Directory of Open Access Journals (Sweden)

    Razi Ahmed

    2013-06-01

    Full Text Available Estimates of above ground biomass density in forests are crucial for refining global climate models and understanding climate change. Although data from field studies can be aggregated to estimate carbon stocks on global scales, the sparsity of such field data, temporal heterogeneity and methodological variations introduce large errors. Remote sensing measurements from spaceborne sensors are a realistic alternative for global carbon accounting; however, the uncertainty of such measurements is not well known and remains an active area of research. This article describes an effort to collect field data at the Harvard and Howland Forest sites, set in the temperate forests of the Northeastern United States in an attempt to establish ground truth forest biomass for calibration of remote sensing measurements. We present an assessment of the quality of ground truth biomass estimates derived from three different sets of diameter-based allometric equations over the Harvard and Howland Forests to establish the contribution of errors in ground truth data to the error in biomass estimates from remote sensing measurements.

  15. Soil Organic Carbon Storage and Stability in the Aspen-Conifer Ecotone in Montane Forests in Utah, USA

    Directory of Open Access Journals (Sweden)

    Mercedes Román Dobarco

    2014-04-01

    Full Text Available To assess the potential impact of conifer encroachment on soil organic carbon (SOC dynamics and storage in montane aspen-conifer forests from the interior western US, we sampled mineral soils (0–15 cm across the aspen-conifer ecotones in southern and northern Utah and quantified total SOC stocks, stable SOC (i.e., mineral-associated SOC (MoM, labile SOC (i.e., light fraction (LF, decomposable (CO2 release during long-term aerobic incubations and soluble SOC (hot water extractable organic carbon (HWEOC. Total SOC storage (47.0 ± 16.5 Mg C ha−1 and labile SOC as LF (14.0 ± 7.10 Mg C ha−1, SOC decomposability (cumulative released CO2-C of 5.6 ± 3.8 g C g−1 soil or HWEOC (0.6 ± 0.6 mg C g−1 soil did not differ substantially with vegetation type, although a slight increase in HWEOC was observed with increasing conifer in the overstory. There were statistically significant differences (p = 0.035 in stable MoM storage, which was higher under aspen (31.2 ± 15.1 Mg C ha−1 than under conifer (22.8 ± 9.0 Mg C ha−1, with intermediate values under mixed (25.7 ± 8.8 Mg C ha−1. Texture had the greatest impact on SOC distribution among labile and stable fractions, with increasing stabilization in MoM and decreasing bio-availability of SOC with increasing silt + clay content. Only at lower silt + clay contents (40%–70% could we discern the influence of vegetation on MoM content. This highlights the importance of chemical protection mechanisms for long-term C sequestration.

  16. Bat Response to Differing Fire Severity in Mixed-Conifer Forest California, USA

    Science.gov (United States)

    Heady, Paul A.; Hayes, John P.; Frick, Winifred F.

    2013-01-01

    Wildlife response to natural disturbances such as fire is of conservation concern to managers, policy makers, and scientists, yet information is scant beyond a few well-studied groups (e.g., birds, small mammals). We examined the effects of wildfire severity on bats, a taxon of high conservation concern, at both the stand (Bat activity in burned areas was either equivalent or higher than in unburned stands for all six phonic groups measured, with four groups having significantly greater activity in at least one burn severity level. Evidence of differentiation between fire severities was observed with some Myotis species having higher levels of activity in stands of high-severity burn. Larger-bodied bats, typically adapted to more open habitat, showed no response to fire. We found differential use of riparian and upland habitats among the phonic groups, yet no interaction of habitat type by fire severity was found. Extent of high-severity fire damage in the landscape had no effect on activity of bats in unburned sites suggesting no landscape effect of fire on foraging site selection and emphasizing stand-scale conditions driving bat activity. Results from this fire in mixed-conifer forests of California suggest that bats are resilient to landscape-scale fire and that some species are preferentially selecting burned areas for foraging, perhaps facilitated by reduced clutter and increased post-fire availability of prey and roosts. PMID:23483936

  17. Airborne S-Band SAR for Forest Biophysical Retrieval in Temperate Mixed Forests of the UK

    Directory of Open Access Journals (Sweden)

    Ramesh K. Ningthoujam

    2016-07-01

    Full Text Available Radar backscatter from forest canopies is related to forest cover, canopy structure and aboveground biomass (AGB. The S-band frequency (3.1–3.3 GHz lies between the longer L-band (1–2 GHz and the shorter C-band (5–6 GHz and has been insufficiently studied for forest applications due to limited data availability. In anticipation of the British built NovaSAR-S satellite mission, this study evaluates the benefits of polarimetric S-band SAR for forest biophysical properties. To understand the scattering mechanisms in forest canopies at S-band the Michigan Microwave Canopy Scattering (MIMICS-I radiative transfer model was used. S-band backscatter was found to have high sensitivity to the forest canopy characteristics across all polarisations and incidence angles. This sensitivity originates from ground/trunk interaction as the dominant scattering mechanism related to broadleaved species for co-polarised mode and specific incidence angles. The study was carried out in the temperate mixed forest at Savernake Forest and Wytham Woods in southern England, where airborne S-band SAR imagery and field data are available from the recent AirSAR campaign. Field data from the test sites revealed wide ranges of forest parameters, including average canopy height (6–23 m, diameter at breast-height (7–42 cm, basal area (0.2–56 m2/ha, stem density (20–350 trees/ha and woody biomass density (31–520 t/ha. S-band backscatter-biomass relationships suggest increasing backscatter sensitivity to forest AGB with least error between 90.63 and 99.39 t/ha and coefficient of determination (r2 between 0.42 and 0.47 for the co-polarised channel at 0.25 ha resolution. The conclusion is that S-band SAR data such as from NovaSAR-S is suitable for monitoring forest aboveground biomass less than 100 t/ha at 25 m resolution in low to medium incidence angle range.

  18. Feeding strategies of primates in temperate and alpine forests: comparison of Asian macaques and colobines.

    Science.gov (United States)

    Tsuji, Yamato; Hanya, Goro; Grueter, Cyril C

    2013-07-01

    We analyzed regional variation in the diets of two primate clades, Asian macaques and colobines, whose distributions include temperate-alpine forests. We addressed feeding strategies that enabled them to adapt to harsh environments characterized by relatively low mean temperatures and strong seasonality in both temperature and food availability. Macaques in tropical-lowland forests feed mainly on fruit and animal matter whereas populations in temperate-alpine forests feed more on foliage and on such items as bark and fungi. In comparison, colobines in tropical-lowland forests feed more on fruit and foliage whereas populations in temperate-alpine forests feed less on flowers and more on lichens. Annual precipitation and mean temperature, both of which reflect primary production, had the most significant effects on the feeding behavior of the macaques, whereas only mean temperature had a significant effect on that of colobines. We found two behavioral strategies used by both clades to cope with severe environmental conditions in temperate-alpine forests--shifting to other food items and adjusting feeding plasticity for fruit and foliage. Macaques responded to latitudinal changes by use of both strategies whereas the colobines adapted by using the latter only. By contrast, changes in altitude resulted in the macaques' using the latter strategy and colobines' using both. The different current distributions of Asian macaques and colobines could be attributed to differences in their feeding strategies originating in their digestive systems.

  19. Assessment of Soil Organic Carbon Stock of Temperate Coniferous Forests in Northern Kashmir

    Directory of Open Access Journals (Sweden)

    Davood A. Dar

    2015-02-01

    Full Text Available  Soil organic carbon (SOC estimation in temperate forests of the Himalaya is important to estimate their contribution to regional, national and global carbon stocks. Physico chemical properties of soil were quantified to assess soil organic carbon density (SOC and SOC CO2 mitigation density at two soil depths (0-10 and 10-20 cms under temperate forest in the Northern region of Kashmir Himalayas India. The results indicate that conductance, moisture content, organic carbon and organic matter were significantly higher while as pH and bulk density were lower at Gulmarg forest site. SOC % was ranging from 2.31± 0.96 at Gulmarg meadow site to 2.31 ± 0.26 in Gulmarg forest site. SOC stocks in these temperate forests were from 36.39 ±15.40 to 50.09 ± 15.51 Mg C ha-1. The present study reveals that natural vegetation is the main contributor of soil quality as it maintained the soil organic carbon stock. In addition, organic matter is an important indicator of soil quality and environmental parameters such as soil moisture and soil biological activity change soil carbon sequestration potential in temperate forest ecosystems.DOI: http://dx.doi.org/10.3126/ije.v4i1.12186International Journal of Environment Volume-4, Issue-1, Dec-Feb 2014/15; page: 161-178

  20. Temperate and Tropical Forest Canopies are Already Functioning beyond Their Thermal Thresholds for Photosynthesis

    Directory of Open Access Journals (Sweden)

    Alida C. Mau

    2018-01-01

    Full Text Available Tropical tree species have evolved under very narrow temperature ranges compared to temperate forest species. Studies suggest that tropical trees may be more vulnerable to continued warming compared to temperate species, as tropical trees have shown declines in growth and photosynthesis at elevated temperatures. However, regional and global vegetation models lack the data needed to accurately represent such physiological responses to increased temperatures, especially for tropical forests. To address this need, we compared instantaneous photosynthetic temperature responses of mature canopy foliage, leaf temperatures, and air temperatures across vertical canopy gradients in three forest types: tropical wet, tropical moist, and temperate deciduous. Temperatures at which maximum photosynthesis occurred were greater in the tropical forests canopies than the temperate canopy (30 ± 0.3 °C vs. 27 ± 0.4 °C. However, contrary to expectations that tropical species would be functioning closer to threshold temperatures, photosynthetic temperature optima was exceeded by maximum daily leaf temperatures, resulting in sub-optimal rates of carbon assimilation for much of the day, especially in upper canopy foliage (>10 m. If trees are unable to thermally acclimate to projected elevated temperatures, these forests may shift from net carbon sinks to sources, with potentially dire implications to climate feedbacks and forest community composition.

  1. Trace Gas Emissions in Temperate Forests and Impact of Forest Conversion

    Science.gov (United States)

    Butterbach-Bahl, K.; Papen, H.

    2003-12-01

    Temperate forest ecosystems play a significant role as sources and sinks for primarily and secondarily active trace gases such as N2O, NO and CH4. In recent decades the magnitude of the biosphere-atmosphere exchange of these trace gases has been substantially altered due to direct and indirect anthropogenic activities. E.g. measurements at different forest sites across Europe exposed to different loads of atmospheric N-deposition clearly show, that N-oxides emissions are positively correlated to N-deposition, whereas CH4 uptake rates are negatively affected. Furthermore, stand properties such as tree species composition as well as stand age have also been demonstrated to strongly affect the exchange of these trace gases. Results of continuous measurements of N-oxide emissions at the Hoglwald Forest site, Germany, show that e.g. NO-emissions from a spruce site are approx. 6 fold higher (5-7 kg NO-N ha-1 yr-1) than N2O emissions (0.5-1 kg N2O-N ha-1 yr-1), whereas at an adjacent beech site -stocking on a comparable soil- N2O-emissions are 3-5 kg N2O-N ha-1 yr-1 and NO emissions are 2-2.5 kg NO-N ha-1 yr-1. These results are further supported by microbiological process studies, which show that the forest type can alter the magnitude of the key microbial processes mineralization and nitrification by its effect on soil moisture conditions and substrate quality. However, estimates of trace gas exchange between temperate forest soils and the atmosphere remain fragmentary if the effect of direct anthropogenic management activities such as clear cutting and reforestation are neglected. Therefore, in 1999 we started a multi-year experiment at the H”glwald Forest, Bavaria, in which we investigated the effect of the conversion of a spruce forest into a beech forest either by clear cutting or selected cutting on N2O, NO and CH4 emission/ deposition. The results of this study show, that clear cutting strongly enhanced N2O emissions from approx. 0.5 kg N2O-N ha-1 yr-1 to >5 kg

  2. A review of the role of temperate forests in the global CO2 balance

    International Nuclear Information System (INIS)

    Musselman, R.C.; Fox, D.G.

    1991-01-01

    The role of temperate forests in the global carbon balance is difficult to determine because many uncertainties exist in the data, and many assumptions must be made in these determinations. Still, there is little doubt that increases in atmospheric CO 2 and global warming would have major effects on temperate forest ecosystems. Increases in atmospheric CO 2 may result in increases in photosynthesis, changes in water and nitrogen use efficiency, and changes in carbon allocation. Indirect effects of changes in global carbon balance on regional climate and on microenvironmental conditions, particularly temperature and moisture, may be more important then direct effects of increased CO 2 on vegetation. Increased incidence of forest perturbations might also be expected. The evidence suggests that conditions favorable to forest growth and development may exist in the northern latitudes, while southern latitude forests may undergo drought stress. Current harvest of temperate and world forests contributes substantial amounts of carbon to the atmosphere, possibly as much as 3 gigatons (Gt) per year. Return of this carbon to forest storage may require decades. Forest managers should be aware of the global as well as local impact their management decisions will have on the atmospheric carbon balance of the ecosystems they oversee

  3. Towards scaling interannual ecohydrological responses of conifer forests to bark beetle infestations from individuals to landscapes

    Science.gov (United States)

    Mackay, D. S.; Ewers, B. E.; Peckham, S. D.; Savoy, P.; Reed, D. E.; Frank, J. M.

    2013-12-01

    Widespread epidemics of forest-damaging insects have severe implications for the interconnections between water and ecosystem processes under present-day climate. How these systems respond to future climates is highly uncertain, and so there is a need for a better understanding of the effects of such disturbances on plant hydraulics, and the consequent effects on ecosystem processes. Moreover, large-scale manifestations of such disturbances require scaling knowledge obtained from individual trees or stands up to a regional extent. This requires a conceptual framework that integrates physical and biological processes that are immutable and scalable. Indeed, in Western North America multiple conifer species have been impacted by the bark beetle epidemic, but the prediction of such widespread outbreaks under changing environmental conditions must be generalized from a relatively small number of ground-based observations. Using model-data fusion we examine the fundamental principles that drive ecological and hydrological responses to bark beetles infestation from individuals to regions. The study includes a mid-elevation (2750 m a.s.l) lodgepole pine forest and higher (3190 m a.s.l.) elevation Engelmann spruce - fir forest in southern Wyoming. The study included a suite of observations, comprising leaf gas exchange, non-structural carbon (NSC), plant hydraulics, including sap flux transpiration (E), vulnerability to cavitation, leaf water potentials, and eddy covariance, were made pre-, during-, and post-disturbance, as the bark beetle infestation moved through these areas. Numerous observations tested hypotheses generated by the Terrestrial Regional Ecosystem Exchange Simulator (TREES), which integrates soil hydraulics and dynamic tree hydraulics (cavitation) with canopy energy and gas exchange, and operates at scales from individuals to landscapes. TREES accurately predicted E and NSC dynamics among individuals spanning pre- and post-disturbance periods, with the 95

  4. Avian community responses to post-fire forest structure: Implications for fire management in mixed conifer forests

    Science.gov (United States)

    White, Angela M.; Manley, Patricia N.; Tarbill, Gina; Richardson, T.L.; Russell, Robin E.; Safford, Hugh D.; Dobrowski, Solomon Z.

    2015-01-01

    Fire is a natural process and the dominant disturbance shaping plant and animal communities in many coniferous forests of the western US. Given that fire size and severity are predicted to increase in the future, it has become increasingly important to understand how wildlife responds to fire and post-fire management. The Angora Fire burned 1243 hectares of mixed conifer forest in South Lake Tahoe, California. We conducted avian point counts for the first 3 years following the fire in burned and unburned areas to investigate which habitat characteristics are most important for re-establishing or maintaining the native avian community in post-fire landscapes. We used a multi-species occurrence model to estimate how avian species are influenced by the density of live and dead trees and shrub cover. While accounting for variations in the detectability of species, our approach estimated the occurrence probabilities of all species detected including those that were rare or observed infrequently. Although all species encountered in this study were detected in burned areas, species-specific modeling results predicted that some species were strongly associated with specific post-fire conditions, such as a high density of dead trees, open-canopy conditions or high levels of shrub cover that occur at particular burn severities or at a particular time following fire. These results indicate that prescribed fire or managed wildfire which burns at low to moderate severity without at least some high-severity effects is both unlikely to result in the species assemblages that are unique to post-fire areas or to provide habitat for burn specialists. Additionally, the probability of occurrence for many species was associated with high levels of standing dead trees indicating that intensive post-fire harvest of these structures could negatively impact habitat of a considerable proportion of the avian community.

  5. Multiple environmental changes drive forest floor vegetation in a temperate mountain forest.

    Science.gov (United States)

    Helm, Norbert; Essl, Franz; Mirtl, Michael; Dirnböck, Thomas

    2017-04-01

    Human-induced changes of the environment and their possible impacts on temperate forest understory plant communities have been examined in many studies. However, the relative contribution of individual environmental factors to these changes in the herb layer is still unclear. In this study, we used vegetation survey data covering a time period of 21 years and collected from 143 permanent plots in the Northern Limestone Alps, Austria. Data on soil chemistry (49 plots), light condition (51 plots), soil temperature and moisture (four and six plots), disturbance (all plots), climate (one station in a clearing area), and airborne sulfur (S) and nitrogen (N) deposition (two forest stands) were available for analyses. We used these data together with plot mean Ellenberg indicator values in a path analysis to attribute their relative contributions to observed vegetation changes. Our analysis reveals a strong directional shift of the forest understory plant community. We found strong evidence for a recovery of the ground-layer vegetation from acidification as response to decreased S deposition. We did not observe a community response to atmospheric N deposition, but we found a response to altered climatic conditions (thermophilization and drying). The path analysis revealed that changes in the light regime, which were related to small-scale disturbances, had most influence on herb layer community shifts. Thermophilization and drying were identified as drivers of understory community changes independent of disturbance events.

  6. Foliar temperature tolerance of temperate and tropical evergreen rain forest trees of Australia.

    Science.gov (United States)

    Cunningham, S C; Read, J

    2006-11-01

    Australian rain forests extend from tropical climates in the north to temperate climates in the south, providing an opportunity to investigate physiological responses to temperature of both temperate and tropical species within the same forest type. Eight, rain forest canopy tree species were selected to cover the 33 degrees latitudinal range of rain forests in eastern Australia. Temperature tolerance was measured in 6-year-old plants grown in a common environment, by exposing leaves to a series of high temperatures during late summer and a series of freezing temperatures during midwinter. Damage was evaluated based on chlorophyll fluorescence measurements made 2 h after exposure and by visual assessment of leaf damage made a week after exposure. Leaves of the tropical species were more heat tolerant and less frost tolerant than leaves of the temperate species, which is consistent with their climate distributions. In contrast, the temperature tolerance of the photosynthetic apparatus was unrelated to climate in a species' native habitat. However, the tropical species underwent significant photoinhibition during winter. All species maintained the integrity of the photosynthetic apparatus and avoided tissue damage over a similar span of temperatures (about 60 degrees C), reflecting the similar annual temperature ranges in Australia's temperate and tropical rain forests. Chlorophyll fluorescence measurements and visual assessment of leaf damage provided different estimates of the absolute and relative temperature tolerances of the species, thus emphasizing the importance of a direct assessment of tissue damage for determining a species' temperature tolerance.

  7. Thermal Acclimation of Photosynthesis and Respiration Differ Across Mature Conifer Species in a Boreal Forest Peatland

    Science.gov (United States)

    Dusenge, M. E.; Stinziano, J. R.; Warren, J.; Ward, E. J.; Wullschleger, S.; Hanson, P. J.; Way, D.

    2017-12-01

    Boreal forests are often assumed to be temperature-limited, and warming is therefore expected to stimulate their carbon uptake. However, much of our information on the ability of boreal conifers to acclimate photosynthesis and respiration to rising temperatures comes from seedlings. We measured net CO2 assimilation rates (A) and dark respiration (R) at 25 °C (A25 and R25) and at prevailing growth temperatures (Ag and Rg) in mature Picea mariana (spruce) and Larix laricina (tamarack) exposed to ambient, +2.25, +4.5, +6.75 and +9 °C warming treatments in open top chambers in the field at the SPRUCE experiment (MN, USA). In spruce, A25 and Ag were similar across plots in May and June. In August, spruce in warmer treatments had higher A25, an effect that was offset by warmer leaf temperatures in the Ag data. In tamarack, A25 was stimulated by warming in both June and August, an effect that was mainly offset by higher leaf temperatures when Ag was assessed in June, while in August, Ag was still slightly higher in the warmest treatments (+6.75 and +9) compared to the ambient plots. In spruce, R25 was enhanced in warm-grown trees in May, but was similar across treatments in June and August, indicating little acclimation of R. Rg slightly increased with warming treatments across the season in spruce. In contrast, R in tamarack thermally acclimated, as R25 decreased with warming. But while this acclimation generated homeostatic Rg in June, Rg in August was still highest in the warmest treatments. Our work suggests that the capacity for thermal acclimation in both photosynthesis and respiration varies among boreal tree species, which may lead to shifts in the performance of these species as the climate warms.

  8. Climate and Vegetation Effects on Temperate Mountain Forest Evapotranspiration

    Science.gov (United States)

    Current forest composition may be resilient to typical climatic variability; however, climate trends, combined with projected changes in species composition, may increase tree vulnerability to water stress. A shift in forest composition toward tree species with higher water use h...

  9. Sediment properties and CO2 efflux from intact and cleared temperate mangrove forests

    Science.gov (United States)

    Bulmer, R. H.; Lundquist, C. J.; Schwendenmann, L.

    2015-10-01

    Temperate mangrove forests in New Zealand have increased in area over recent decades. Expansion of temperate mangroves in New Zealand is associated with perceived loss of other estuarine habitats, and decreased recreational and amenity values, resulting in clearing of mangrove forests. In the tropics, changes in sediment characteristics and carbon efflux have been reported following mangrove clearance. This is the first study in temperate mangrove (Avicennia marina) forests investigating the impact of clearing on sediment CO2 efflux and associated biotic and abiotic factors. Sediment CO2 efflux rates from intact (168.5 ± 45.8 mmol m-2 d-1) and cleared (133.9 ± 37.2 mmol m-2 d-1) mangrove forests in New Zealand are comparable to rates measured in tropical mangrove forests. We did not find a significant difference in sediment CO2 efflux rates between intact and cleared temperate mangrove forests. Pre-shading the sediment for more than 30 min prior to dark chamber measurements was found to have no significant effect on sediment CO2 efflux. This suggests that the continuation of photosynthetic CO2 uptake by biofilm communities was not occurring after placement of dark chambers. Rather, above-ground mangrove biomass, sediment temperature and chlorophyll a concentration were the main factors explaining the variability in sediment CO2 efflux in intact mangrove forests. The main factors influencing sediment CO2 efflux in cleared mangrove forest sites were sediment organic carbon concentration, nitrogen concentration and sediment grain size. Our results show that greater consideration should be given regarding the rate of carbon released from mangrove forest following clearance and the relative contribution to global carbon emissions.

  10. Examining Historical and Current Mixed-Severity Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

    Science.gov (United States)

    Odion, Dennis C.; Hanson, Chad T.; Arsenault, André; Baker, William L.; DellaSala, Dominick A.; Hutto, Richard L.; Klenner, Walt; Moritz, Max A.; Sherriff, Rosemary L.; Veblen, Thomas T.; Williams, Mark A.

    2014-01-01

    There is widespread concern that fire exclusion has led to an unprecedented threat of uncharacteristically severe fires in ponderosa pine (Pinus ponderosa Dougl. ex. Laws) and mixed-conifer forests of western North America. These extensive montane forests are considered to be adapted to a low/moderate-severity fire regime that maintained stands of relatively old trees. However, there is increasing recognition from landscape-scale assessments that, prior to any significant effects of fire exclusion, fires and forest structure were more variable in these forests. Biota in these forests are also dependent on the resources made available by higher-severity fire. A better understanding of historical fire regimes in the ponderosa pine and mixed-conifer forests of western North America is therefore needed to define reference conditions and help maintain characteristic ecological diversity of these systems. We compiled landscape-scale evidence of historical fire severity patterns in the ponderosa pine and mixed-conifer forests from published literature sources and stand ages available from the Forest Inventory and Analysis program in the USA. The consensus from this evidence is that the traditional reference conditions of low-severity fire regimes are inaccurate for most forests of western North America. Instead, most forests appear to have been characterized by mixed-severity fire that included ecologically significant amounts of weather-driven, high-severity fire. Diverse forests in different stages of succession, with a high proportion in relatively young stages, occurred prior to fire exclusion. Over the past century, successional diversity created by fire decreased. Our findings suggest that ecological management goals that incorporate successional diversity created by fire may support characteristic biodiversity, whereas current attempts to “restore” forests to open, low-severity fire conditions may not align with historical reference conditions in most ponderosa

  11. Influence of different tree-harvesting intensities on forest soil carbon stocks in boreal and northern temperate forest ecosystems

    DEFF Research Database (Denmark)

    Clarke, Nicholas; Gundersen, Per; Jönsson-Belyazid, Ulrika

    2015-01-01

    processes involved, and under which conditions the size of the removals becomes critical. At present, the uncertainty gap between the scientific results and the need for practically useable management guidelines and other governance measures might be bridged by expert opinions given to authorities......Effective forest governance measures are crucial to ensure sustainable management of forests, but so far there has been little specific focus in boreal and northern temperate forests on governance measures in relation to management effects, including harvesting effects, on soil organic carbon (SOC......) stocks. This paper reviews the findings in the scientific literature concerning the effects of harvesting of different intensities on SOC stocks and fluxes in boreal and northern temperate forest ecosystems to evaluate the evidence for significant SOC losses following biomass removal. An overview...

  12. Suitability of close-to-nature silviculture for adapting temperate European forests to climate change

    OpenAIRE

    Brang, P.; Spathelf, P.; Larsen, J.B.; Bauhus, J.; Boncina, A.; Chauvin, C.; Drössler, L.; Garcia-Güemes, C.; Heiri, C.; Kerr, G.; Lexer, M.J.; Mason, B.; Mohren, F.; Mühlethaler, U.; Nocentini, S.

    2014-01-01

    International audience; In many parts of Europe, close-to-nature silviculture (CNS) has been widely advocated as being the best approach for managing forests to cope with future climate change. In this review, we identify and evaluate six principles for enhancing the adaptive capacity of European temperate forests in a changing climate: (1) increase tree species richness, (2) increase structural diversity, (3) maintain and increase genetic variation within tree species, (4) increase resistanc...

  13. Historical dominance of low-severity fire in dry and wet mixed-conifer forest habitats of the endangered terrestrial Jemez Mountains salamander (Plethodon neomexicanus)

    Science.gov (United States)

    Margolis, Ellis; Malevich, Steven B.

    2016-01-01

    Anthropogenic alteration of ecosystem processes confounds forest management and conservation of rare, declining species. Restoration of forest structure and fire hazard reduction are central goals of forest management policy in the western United States, but restoration priorities and treatments have become increasingly contentious. Numerous studies have documented changes in fire regimes, forest stand structure and species composition following a century of fire exclusion in dry, frequent-fire forests of the western U.S. (e.g., ponderosa pine and dry mixed-conifer). In contrast, wet mixed-conifer forests are thought to have historically burned infrequently with mixed- or high-severity fire—resulting in reduced impacts from fire exclusion and low restoration need—but data are limited. In this study we quantified the current forest habitat of the federally endangered, terrestrial Jemez Mountains salamander (Plethodon neomexicanus) and compared it to dendroecological reconstructions of historical habitat (e.g., stand structure and composition), and fire regime parameters along a gradient from upper ponderosa pine to wet mixed-conifer forests. We found that current fire-free intervals in Jemez Mountains salamander habitat (116–165 years) are significantly longer than historical intervals, even in wet mixed-conifer forests. Historical mean fire intervals ranged from 10 to 42 years along the forest gradient. Low-severity fires were historically dominant across all forest types (92 of 102 fires). Although some mixed- or highseverity fire historically occurred at 67% of the plots over the last four centuries, complete mortality within 1.0 ha plots was rare, and asynchronous within and among sites. Climate was an important driver of temporal variability in fire severity, such that mixed- and high-severity fires were associated with more extreme drought than low-severity fires. Tree density in dry conifer forests historically ranged from open (90 trees/ha) to

  14. Drivers of temporal changes in temperate forest plant diversity vary across spatial scales

    Czech Academy of Sciences Publication Activity Database

    Bernhardt-Römermann, M.; Baeten, L.; Craven, D.; De Frenne, P.; Hédl, Radim; Lenoir, J.; Bert, D.; Brunet, J.; Chudomelová, Markéta; Decocq, G.; Dierschke, H.; Dirnböck, T.; Dörfler, I.; Heinken, T.; Hermy, M.; Hommel, P.; Jaroszewicz, B.; Keczynski, A.; Kelly, D. L.; Kirkby, K.J.; Kopecký, Martin; Macek, Martin; Máliš, F.; Mirtl, M.; Mitchell, F. J. G.; Naaf, T.; Newman, M.; Peterken, G.; Petřík, Petr; Schmidt, W.; Standovár, T.; Tóth, Z.; Van Calster, H.; Verstraeten, G.; Vladovič, J.; Vild, Ondřej; Wulf, M.; Verheyen, K.

    2015-01-01

    Roč. 21, č. 10 (2015), s. 3726-3737 ISSN 1354-1013 R&D Projects: GA MŠk(CZ) EE2.3.20.0267 EU Projects: European Commission(XE) 278065 - LONGWOOD Institutional support: RVO:67985939 Keywords : temperate forest * long-term change * herbaceous layer Subject RIV: EF - Botanics Impact factor: 8.444, year: 2015

  15. Forest dynamics in the temperate rainforests of Alaska: from individual tree to regional scales

    Science.gov (United States)

    Tara M. Barrett

    2015-01-01

    Analysis of remeasurement data from 1079 Forest Inventory and Analysis (FIA) plots revealed multi-scale change occurring in the temperate rainforests of southeast Alaska. In the western half of the region, including Prince William Sound, aboveground live tree biomass and carbon are increasing at a rate of 8 ( ± 2 ) percent per decade, driven by an increase in Sitka...

  16. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

    Science.gov (United States)

    Alan F. Talhelm; Kurt S. Pregitzer; Mark E. Kubiske; Donald R. Zak; Courtney E. Campany; Andrew J. Burton; Richard E. Dickson; George R. Hendrey; J. G. Isebrands; Keith F. Lewin; John Nagy; David F. Karnosky

    2014-01-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment...

  17. The northern flying squirrel as an indicator species of temperate rain forest: test of an hypothesis.

    Science.gov (United States)

    Winston P. Smith; Scott M. Gende; Jeffrey V. Nichols

    2005-01-01

    Management indicator species (MIS) often are selected because their life history and demographics are thought to reflect a suite of ecosystem conditions that are too difficult or costly to measure directly. The northern flying squirrel (Glaucomys sabrinus) has been proposed as an MIS of temperate rain forest of southeastern Alaska based on previous...

  18. Substrate and nutrient limitation of ammonia-oxidizing bacteria and archaea in temperate forest soil

    Science.gov (United States)

    J.S. Norman; J.E. Barrett

    2014-01-01

    Ammonia-oxidizing microbes control the rate-limiting step of nitrification, a critical ecosystem process, which affects retention and mobility of nitrogen in soil ecosystems. This study investigated substrate (NH4þ) and nutrient (K and P) limitation of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in temperate forest soils at Coweeta Hydrologic...

  19. Effect of 40 and 80 Years of Conifer Regrowth on Soil Microbial Activities and Community Structure in Subtropical Low Mountain Forests

    Directory of Open Access Journals (Sweden)

    Ed-Haun Chang

    2016-10-01

    Full Text Available The effects of long-term reforestation on soil microbial communities and biomass are poorly understood. This study was conducted on two coniferous plantations: Cunninghamia konishii Hayata, planted 40 years ago (CONIF-40, and Calocedrus formosana (Florin Florin, planted 80 years ago (CONIF-80. An adjacent natural broadleaf forest (BROAD-Nat was used as a control. We determined microbial biomass C and N contents, enzyme activities, and community composition (via phospholipid fatty acid [PLFA] assessment. Both microbial biomass and PLFA content were higher in the summer than in the winter and differed among the forests in summer only. Total PLFA, total bacterial, gram-positive bacterial, gram-negative bacterial, and vesicular arbuscular mycorrhizal fungal contents followed the same pattern. Total fungal content and the ratios of fungi to bacteria and of gram-positive to gram-negative bacteria were highest in CONIF-40, with no difference between the other forests. Principal component analysis of PLFA contents revealed that CONIF-40 communities were distinct from those of CONIF-80 and BROAD-Nat. Our results suggest that vegetation replacement during reforestation exerts a prolonged impact on the soil microbial community. The understory broadleaf shrubs and trees established after coniferous plantation reforestation may balance out the effects of coniferous litter, contributing to bacterial recovery.

  20. Carbon accretion in unthinned and thinned young-growth forest stands of the Alaskan perhumid coastal temperate rainforest.

    Science.gov (United States)

    D'Amore, David V; Oken, Kiva L; Herendeen, Paul A; Steel, E Ashley; Hennon, Paul E

    2015-12-01

    Accounting for carbon gains and losses in young-growth forests is a key part of carbon assessments. A common silvicultural practice in young forests is thinning to increase the growth rate of residual trees. However, the effect of thinning on total stand carbon stock in these stands is uncertain. In this study we used data from 284 long-term growth and yield plots to quantify the carbon stock in unthinned and thinned young growth conifer stands in the Alaskan coastal temperate rainforest. We estimated carbon stocks and carbon accretion rates for three thinning treatments (basal area removal of 47, 60, and 73 %) and a no-thin treatment across a range of productivity classes and ages. We also accounted for the carbon content in dead trees to quantify the influence of both thinning and natural mortality in unthinned stands. The total tree carbon stock in naturally-regenerating unthinned young-growth forests estimated as the asymptote of the accretion curve was 484 (±26) Mg C ha -1 for live and dead trees and 398 (±20) Mg C ha -1 for live trees only. The total tree carbon stock was reduced by 16, 26, and 39 % at stand age 40 y across the increasing range of basal area removal. Modeled linear carbon accretion rates of stands 40 years after treatment were not markedly different with increasing intensity of basal area removal from reference stand values of 4.45 Mg C ha -1  year -1 to treatment stand values of 5.01, 4.83, and 4.68 Mg C ha -1  year -1 respectively. However, the carbon stock reduction in thinned stands compared to the stock of carbon in the unthinned plots was maintained over the entire 100 year period of observation. Thinning treatments in regenerating forest stands reduce forest carbon stocks, while carbon accretion rates recovered and were similar to unthinned stands. However, that the reduction of carbon stocks in thinned stands persisted for a century indicate that the unthinned treatment option is the optimal choice for short

  1. Increased Drought Impacts on Temperate Rainforests from Southern South America: Results of a Process-Based, Dynamic Forest Model

    OpenAIRE

    Gutiérrez, Alvaro G.; Armesto, Juan J.; Díaz, M. Francisca; Huth, Andreas

    2014-01-01

    Increased droughts due to regional shifts in temperature and rainfall regimes are likely to affect forests in temperate regions in the coming decades. To assess their consequences for forest dynamics, we need predictive tools that couple hydrologic processes, soil moisture dynamics and plant productivity. Here, we developed and tested a dynamic forest model that predicts the hydrologic balance of North Patagonian rainforests on Chiloé Island, in temperate South America (42°S). The model incor...

  2. Temperate forest dynamics and carbon storage: A 26-year case ...

    African Journals Online (AJOL)

    Overall, these results suggest that the forest is in a post-disturbance recovery phase, although favourable climatic conditions over the last three decades may also have had an influence on AGB accumulation. Keywords: aboveground biomass, carbon sequestration, forest conservation, long-term monitoring, succession ...

  3. [Effect of forest management on the herpetofauna of a temperate forest of western Oaxaca, Mexico].

    Science.gov (United States)

    Aldape-López, César Tonatiuh; Santos-Moreno, Antonio

    2016-09-01

    The development of silvicultural techniques has as main objective to maximize the production of timber, whereas at the same time minimize the impact generated during and after forest intervention in the local diversity. However, these activities change local climate, and this, in turn, alter the composition of natural communities. The effect of these changes may be greater in those taxonomic groups with high sensitivity to habitat disturbance, such as amphibians and reptiles, which are the unique terrestrial ectothermic vertebrates. The present study aims to know the differences in diversity of amphibians and reptiles in a temperate forest under two silvicultural treatments, one of low and the other of high intensity, as well as from one, five and ten years of regeneration since the last logging event, Sierra Sur of Oaxaca, Mexico. Records of 21 species of herpetofauna (six amphibians and 15 reptiles) were obtained. The total species richness was similar in both treatments; however, the composition varied between sites with different recovery times. Higher abundance of amphibian was presented on sites with the low-intensity treatment, while reptiles were more abundant at sites with intensive treatment. Compared to a mature forest without management, sites with intensive treatment have more rare species, although the values of true diversity of amphibians were similar between treatments with different intensities, while for reptiles sites under treatment showed less diversity that unmanaged site: 33 % for intensive treatment and 28 % at sites with low intensity with respect to one control site. Complementary Analysis showed a difference of 86 % between the compositions of species in sites with intensive treatment. The treatment intensity was associated with an increase in the number of species, but the way they respond to changes in habitat depends largely on the population characteristics of each species and its ability to adapt to new conditions.

  4. The lack of adequate quality assurance/quality control data hinders the assessment of potential forest degradation in a national forest inventory

    Science.gov (United States)

    Thomas Brandeis; Stanley Zarnoch; Christopher Oswalt; Jeffery Stringer

    2017-01-01

    Hardwood lumber harvested from the temperate broadleaf and mixed broadleaf/conifer forests of the east-central United States is an important economic resource. Forest industry stakeholders in this region have a growing need for accurate, reliable estimates of high-quality wood volume. While lower-graded timber has an increasingly wide array of uses, the forest products...

  5. Fire severity alters the distribution of pyrogenic carbon stocks across ecosystem pools in a Californian mixed-conifer forest

    Science.gov (United States)

    Maestrini, Bernardo; Alvey, Erin C.; Hurteau, Matthew D.; Safford, Hugh; Miesel, Jessica R.

    2017-09-01

    Pyrogenic carbon (PyC) is hypothesized to play an important role in the carbon (C) cycle due to its resistance to decomposition; however, much uncertainty still exists regarding the stocks of PyC that persist on-site after the initial erosion in postfire forests. Therefore, understanding how fire characteristics influence PyC stocks is vital, particularly in the context of California forests for which an increase of high-severity fires is predicted over the next decades. We measured forest C and persistent PyC stocks in areas burned by low-to-moderate and high-severity fire, as well as in adjacent unburned areas in a California mixed-conifer forest, 2 to 3 years after wildfire. We measured C and PyC stocks in the following compartments: standing trees, downed wood, forest floor, and mineral soil (0-5 cm), and we identified PyC using the weak nitric acid digestion method. We found that the total stock of PyC did not differ among fire severity classes (overall mean 248 ± 30 g C m-2); however, fire severity influenced the distribution of PyC in the individual compartments. Areas burned by high-severity fire had 2.5 times more PyC stocked in the coarse woody debris (p stocked in standing trees (p stock in the forest floor (-22%, p losses through erosion.

  6. Upper canopy pollinators of Eucryphia cordifolia Cav., a tree of South American temperate rain forest

    Directory of Open Access Journals (Sweden)

    Cecilia Smith-Ramírez

    2016-05-01

    Full Text Available Ecological processes in the upper canopy of temperate forests have been seldom studied because of the limited accessibility. Here, we present the results of the first survey of the pollinator assemblage and the frequency of insect visits to flowers in the upper branches of ulmo, Eucryphia cordifolia Cav., an emergent 30-40 m-tall tree in rainforests of Chiloé Island, Chile. We compared these findings with a survey of flower visitors restricted to lower branches of E. cordifolia 1- in the forest understory, 2- in lower branches in an agroforestry area. We found 10 species of pollinators in canopy, and eight, 12 and 15 species in understory, depending of tree locations. The main pollinators of E. cordifolia in the upper canopy differed significantly from the pollinator assemblage recorded in lower tree branches. We conclude that the pollinator assemblages of the temperate forest canopy and interior are still unknown.

  7. Brown world forests: increased ungulate browsing keeps temperate trees in recruitment bottlenecks in resource hotspots.

    Science.gov (United States)

    Churski, Marcin; Bubnicki, Jakub W; Jędrzejewska, Bogumiła; Kuijper, Dries P J; Cromsigt, Joris P G M

    2017-04-01

    Plant biomass consumers (mammalian herbivory and fire) are increasingly seen as major drivers of ecosystem structure and function but the prevailing paradigm in temperate forest ecology is still that their dynamics are mainly bottom-up resource-controlled. Using conceptual advances from savanna ecology, particularly the demographic bottleneck model, we present a novel view on temperate forest dynamics that integrates consumer and resource control. We used a fully factorial experiment, with varying levels of ungulate herbivory and resource (light) availability, to investigate how these factors shape recruitment of five temperate tree species. We ran simulations to project how inter- and intraspecific differences in height increment under the different experimental scenarios influence long-term recruitment of tree species. Strong herbivore-driven demographic bottlenecks occurred in our temperate forest system, and bottlenecks were as strong under resource-rich as under resource-poor conditions. Increased browsing by herbivores in resource-rich patches strongly counteracted the increased escape strength of saplings in these patches. This finding is a crucial extension of the demographic bottleneck model which assumes that increased resource availability allows plants to more easily escape consumer-driven bottlenecks. Our study demonstrates that a more dynamic understanding of consumer-resource interactions is necessary, where consumers and plants both respond to resource availability. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  8. Dissimilar bill shapes in new world tropical versus temperate forest foliage-gleaning birds.

    Science.gov (United States)

    Greenberg, Russell

    1981-05-01

    The bill shape of foliage-gleaning birds in temperate and tropical new world forests is dissimilar. Tropical species have longer and narrower bills than their temperate zone counterparts. In addition, their bills are longer for a given body size. These differences cannot be readily explained as phylogenetic artifacts. I suggest that the distinct bill morphology of the two assemblages is determined by the type of insects that comprise the largest size classes of potential prey. These large insects are particularly important since they generally comprise the bulk of the nestling diet for insectivorous birds. In tropical forests Orthoptera are probably the most abundant large soft-bodied arthropods; they form an important resource for foliage-gleaning birds during the breeding (rainy) seasons. Most temperate zone foliage-gleaning birds rely almost entirely upon caterpillars when breeding. Long, narrow bills are thought to close more rapidly than shorter, broader bills. These long, "fast" bills may be required to efficiently harvest active Orthoptera. Migrant warblers may face morphological constraints from breeding successfully in lowland tropical forests. While the short-billed temperate zone birds can survive the tropical dry season by foraging on small arthropods, they may be inefficient at handling large Orthoptera to feed to nestlings.

  9. Thinning, tree-growth, and resistance to multi-year drought in a mixed-conifer forest of northern California

    Science.gov (United States)

    Vernon, Michael J.; Sherriff, Rosemary L.; van Mantgem, Phillip; Kane, Jeffrey M.

    2018-01-01

    Drought is an important stressor in forest ecosystems that can influence tree vigor and survival. In the U.S., forest managers use two primary management techniques to promote resistance and resilience to drought: prescribed fire and mechanical thinning. Generally applied to reduce fuels and fire hazard, treatments may also reduce competition for resources that may improve tree-growth and reduce mortality during drought. A recent severe and prolonged drought in California provided a natural experiment to investigate tree-growth responses to fuel treatments and climatic stress. We assessed tree-growth from 299 ponderosa pine (Pinus ponderosa) and Douglas-fir (Pseudotsuga menziesii) in treated and untreated stands during severe drought from 2012 to 2015 in the mixed-conifer forests of Whiskeytown National Recreation Area (WNRA) in northern California. The treatment implemented at WNRA removed 34% of live basal area through mechanical thinning with a subsequent pile burning of residual fuels. Tree-growth was positively associated with crown ratio and negatively associated with competition and a 1-year lag of climate water deficit, an index of drought. Douglas-fir generally had higher annual growth than ponderosa pine, although factors affecting growth were the same for both species. Drought resistance, expressed as the ratio between mean growth during drought and mean growth pre-drought, was higher in treated stands compared to untreated stands during both years of severe drought (2014 and 2015) for ponderosa pine but only one year (2014) for Douglas-fir. Thinning improved drought resistance, but tree size, competition and species influenced this response. On-going thinning treatments focused on fuels and fire hazard reduction are likely to be effective at promoting growth and greater drought resistance in dry mixed-conifer forests. Given the likelihood of future droughts, land managers may choose to implement similar treatments to reduce potential impacts.

  10. Nitrogen Deposition Effects on Soil Carbon Dynamics in Temperate Forests

    DEFF Research Database (Denmark)

    Ginzburg Ozeri, Shimon

    incubated in litterbags had significantly lower late-stage decomposition rates compared with control litter. However, potential respiration of forest floor and mineral soil was overall unaffected by the experimental N-additions. A temperature treatment of forest floor samples taken from one edge site...... by needle litterfall were generally not significantly affected by N deposition at the edge sites but tended to increase with increasing distance from the edge in two of the N-saturated sites. The experimental N additions resulted in reduced C inputs by foliar litter relative to control concomitant...... reduced belowground C inputs under elevated N deposition. At two edge sites, forest floor C outputs by respiration tended to decrease with decreased forest floor C/N and distance from the edge indicating positive effect of elevated N deposition on SOC sequestration. Correspondingly, N-enriched litter...

  11. Seasonal variation in surface fuel moisture between unthinned and thinned mixed conifer forest, northern California, USA

    Science.gov (United States)

    Becky L. Estes; Eric E. Knapp; Carl N. Skinner; Fabian C. C. Uzoh

    2012-01-01

    Reducing stand density is often used as a tool for mitigating the risk of high-intensity crown fires. However, concern has been expressed that opening stands might lead to greater drying of surface fuels, contributing to increased fire risk. The objective of this study was to determine whether woody fuel moisture differed between unthinned and thinned mixed-conifer...

  12. Height development of shade-tolerant conifer saplings in multiaged Acadian forest stands

    Science.gov (United States)

    Andrew R. Moores; Robert S. Seymour; Laura S. Kenefic

    2007-01-01

    Understory growth dynamics of northern conifer species were studied in four stands managed under multiaged silvicultural systems in eastern Maine. Height growth of Picea rubens Sarg., Abies balsamea (L.) Mill., and Tsuga canadensis (L.) Carr. saplings between 0.5 and 6.0 m in height was related to the proportion...

  13. Canopy arthropod responses to thinning and burning treatments in old-growth mixed-conifer forest in the Sierra Nevada, California

    Science.gov (United States)

    Thomas Rambo; Timothy Schowalter; Malcolm North

    2014-01-01

    We compared canopy arthropod responses to common fuels reduction treatments at Teakettle Experimental Forest in the south-central Sierra Nevada of California. We sampled arthropod communities among four dominant overstory conifer species and three dominant understory angiosperm species before and after overstory or understory thinning or no thinning treatments followed...

  14. Potential climate change impacts on temperate forest ecosystem processes

    Science.gov (United States)

    Peters, Emily B.; Wythers, Kirk R.; Zhang, Shuxia; Bradford, John B.; Reich, Peter B.

    2013-01-01

    Large changes in atmospheric CO2, temperature and precipitation are predicted by 2100, yet the long-term consequences for carbon, water, and nitrogen cycling in forests are poorly understood. We applied the PnET-CN ecosystem model to compare the long-term effects of changing climate and atmospheric CO2 on productivity, evapotranspiration, runoff, and net nitrogen mineralization in current Great Lakes forest types. We used two statistically downscaled climate projections, PCM B1 (warmer and wetter) and GFDL A1FI (hotter and drier), to represent two potential future climate and atmospheric CO2 scenarios. To separate the effects of climate and CO2, we ran PnET-CN including and excluding the CO2 routine. Our results suggest that, with rising CO2 and without changes in forest type, average regional productivity could increase from 67% to 142%, changes in evapotranspiration could range from –3% to +6%, runoff could increase from 2% to 22%, and net N mineralization could increase 10% to 12%. Ecosystem responses varied geographically and by forest type. Increased productivity was almost entirely driven by CO2 fertilization effects, rather than by temperature or precipitation (model runs holding CO2 constant showed stable or declining productivity). The relative importance of edaphic and climatic spatial drivers of productivity varied over time, suggesting that productivity in Great Lakes forests may switch from being temperature to water limited by the end of the century.

  15. Are temperate mature forests buffered from invasive lianas?

    Science.gov (United States)

    Pavlovic, Noel B.; Leicht-Young, Stacey A.

    2011-01-01

    Mature and old-growth forests are often thought to be buffered against invasive species due to low levels of light and infrequent disturbance. Lianas (woody vines) and other climbing plants are also known to exhibit lower densities in older forests. As part of a larger survey of the lianas of the southern Lake Michigan region in mature and old-growth forests, the level of infestation by invasive lianas was evaluated. The only invasive liana detected in these surveys was Celastrus orbiculatus Thunb. (Celastraceae). Although this species had only attached to trees and reached the canopy in a few instances, it was present in 30% of transects surveyed, mostly as a component of the ground layer. Transects with C. orbiculatus had higher levels of soil potassium and higher liana richness than transects without. In contrast, transects with the native C. scandens had higher pH, sand content, and soil magnesium and lower organic matter compared to transects where it was absent. Celastrus orbiculatus appears to be a generalist liana since it often occurs with native lianas. Celastrus orbiculatus poses a substantial threat to mature forests as it will persist in the understory until a canopy gap or other disturbance provides the light and supports necessary for it to ascend to the canopy and damage tree species. As a result, these forests should be monitored by land managers so that C. orbiculatus eradication can occur while invasions are at low densities and restricted to the ground layer.

  16. Vertical stratification of beetles (Coleoptera) and flies (Diptera) in temperate forest canopies.

    Science.gov (United States)

    Maguire, Dorothy Y; Robert, Katleen; Brochu, Kristen; Larrivée, Maxim; Buddle, Christopher M; Wheeler, Terry A

    2014-02-01

    Forest canopies support high arthropod biodiversity, but in temperate canopies, little is known about the spatial distribution of these arthropods. This is an important first step toward understanding ecological roles of insects in temperate canopies. The objective of this study was to assess differences in the species composition of two dominant and diverse taxa (Diptera and Coleoptera) along a vertical gradient in temperate deciduous forest canopies. Five sugar maple trees from each of three deciduous forest sites in southern Quebec were sampled using a combination of window and trunk traps placed in three vertical strata (understory, mid-canopy, and upper-canopy) for three sampling periods throughout the summer. Coleoptera species richness and abundance did not differ between canopy heights, but more specimens and species of Diptera were collected in the upper-canopy. Community composition of Coleoptera and Diptera varied significantly by trap height. Window traps collected more specimens and species of Coleoptera than trunk traps, although both trap types should be used to maximize representation of the entire Coleoptera community. There were no differences in abundance, diversity, or composition of Diptera collected between trap types. Our data confirm the relevance of sampling all strata in a forest when studying canopy arthropod biodiversity.

  17. Variation in Carbon Storage and Its Distribution by Stand Age and Forest Type in Boreal and Temperate Forests in Northeastern China

    Science.gov (United States)

    Wei, Yawei; Li, Maihe; Chen, Hua; Lewis, Bernard J.; Yu, Dapao; Zhou, Li; Zhou, Wangming; Fang, Xiangmin; Zhao, Wei; Dai, Limin

    2013-01-01

    The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and forests respectively, and thus play a minor role in total forest C storage in NE China. PMID:23977252

  18. Local-Scale Drivers of Tree Survival in a Temperate Forest

    Science.gov (United States)

    Wang, Xugao; Comita, Liza S.; Hao, Zhanqing; Davies, Stuart J.; Ye, Ji; Lin, Fei; Yuan, Zuoqiang

    2012-01-01

    Tree survival plays a central role in forest ecosystems. Although many factors such as tree size, abiotic and biotic neighborhoods have been proposed as being important in explaining patterns of tree survival, their contributions are still subject to debate. We used generalized linear mixed models to examine the relative importance of tree size, local abiotic conditions and the density and identity of neighbors on tree survival in an old-growth temperate forest in northeastern China at three levels (community, guild and species). Tree size and both abiotic and biotic neighborhood variables influenced tree survival under current forest conditions, but their relative importance varied dramatically within and among the community, guild and species levels. Of the variables tested, tree size was typically the most important predictor of tree survival, followed by biotic and then abiotic variables. The effect of tree size on survival varied from strongly positive for small trees (1–20 cm dbh) and medium trees (20–40 cm dbh), to slightly negative for large trees (>40 cm dbh). Among the biotic factors, we found strong evidence for negative density and frequency dependence in this temperate forest, as indicated by negative effects of both total basal area of neighbors and the frequency of conspecific neighbors. Among the abiotic factors tested, soil nutrients tended to be more important in affecting tree survival than topographic variables. Abiotic factors generally influenced survival for species with relatively high abundance, for individuals in smaller size classes and for shade-tolerant species. Our study demonstrates that the relative importance of variables driving patterns of tree survival differs greatly among size classes, species guilds and abundance classes in temperate forest, which can further understanding of forest dynamics and offer important insights into forest management. PMID:22347996

  19. [Odocoileus virginianus diet (Artiodactyla: Cervidae) in a temperate forest of Northern Oaxaca, Mexico].

    Science.gov (United States)

    González, Graciela; Briones-Salas, Miguel

    2012-03-01

    The Sierra Madre de Oaxaca region, located in the Northern state of Oaxaca, Mexico, is an area of forest ecosystems subject to high exploitation rates, although in some areas its temperate forests are conserved by indigenous community initiatives that live there. We analyzed the diet of white tailed-deer (Odocoileus virginianus) in the localities of Santa Catarina Lachatao and San Miguel Amatlán from June 1998 to August 1999. Sampling was done during both the wet and dry seasons, and included the observation of browsing traces (238 observations), microhistological analysis of deer feces (28 deer pellet-groups), and two stomach content analysis. The annual diet of white-tailed deer was composed of 42 species from 23 botanical families. The most represented families in the diet of this deer were Fagaceae, Asteraceae, Ericaceae and Fabaceae. There were significant differences in the alpha diversity of the diet during the wet and dry seasons (H'=2.957 and H'=1.832, respectively). The similarity percentage between seasons was 56%. Differences in plant species frequency were significantly higher during the wet season. Herbaceous plants made up the greatest percentage of all the species consumed. The preferred species throughout the year were Senecio sp. (shrub), Sedum dendroideum (herbaceous), Arctostaphylos pungens (shrub) and Satureja macrostema (shrub). Diet species richness was found to be lower than that observed in a tropical forest (Venezuela), tropical dry forest (Mexico) and temperate deciduous and mixed forest (Mexico), but similar to the diet species richness observed in a tropical dry forest (Costa Rica) and temperate coniferous and deciduous forests (USA).

  20. Gap-based silviculture in a sierran mixed-conifer forest: effects of gap size on early survival and 7-year seedling growth

    Science.gov (United States)

    Robert A. York; John J. Battles; Robert C. Heald

    2007-01-01

    Experimental canopy gaps ranging in size from 0.1 to 1.0 ha (0.25 to 2.5 acres) were created in a mature mixed conifer forest at Blodgett Forest Research Station, California. Following gap creation, six species were planted in a wagon-wheel design and assessed for survival after two growing seasons. Study trees were measured after seven years to describe the effect of...

  1. CO2 balance of boreal, temperate, and tropical forests

    NARCIS (Netherlands)

    Luyssaert, S.; Inglima, I.; Jungs, M.; Richardson, A.; Reichsteins, M.; Papale, D.; Piao, S.L.; Schulzes, E.D.; Wingate, L.; Matteucci, G.; Aragaoss, L.; Aubinet, M.; Beers, van C.; Bernhofer, C.; Black, K.G.; Bonal, D.; Bonnefonds, J.M.; Chambers, J.; Ciais, P.; Cook, B.; Davis, K.J.; Dolman, A.J.; Gielen, B.; Goulden, M.; Grace, J.; Granier, A.; Grelle, A.; Griffis, T.; Grunwald, T.; Guidolotti, G.; Hanson, P.J.; Harding, R.; Hollinger, D.Y.; Hutyra, L.R.; Kolari, P.; Kruijt, B.; Kutsch, W.; Lagergren, F.; Laurila, T.; Law, B.E.; Maire, Le G.; Lindroth, A.; Loustau, D.; Malhi, Y.; Mateus, J.; Migliavacca, M.; Misson, L.; Montagnani, L.; Moncrief, J.; Moors, E.J.; Munger, J.W.; Nikinmaa, E.; Ollinger, S.V.; Pita, G.; Rebmann, C.; Roupsard, O.; Saigusa, N.; Sanz, M.J.; Seufert, G.; Sierra, C.; Smith, M.; Tang, J.; Valentini, R.; Vesala, T.; Janssens, I.A.

    2007-01-01

    Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are

  2. Climate and Vegetation Effects on Temperate Mountain Forest ...

    Science.gov (United States)

    Current forest composition may be resilient to typical climatic variability; however, climate trends, combined with projected changes in species composition, may increase tree vulnerability to water stress. A shift in forest composition toward tree species with higher water use has implications for biogenic emissions and deposition of reactive nitrogen and carbon compounds. Forest evapotranspiration (ET) can vary greatly at daily and seasonal time scales, but compared to carbon fluxes, often exhibits relatively consistent inter-annual behavior. The processes controlling ET involve the combined effects of physical and biological factors. Atmospheric conditions that promote high ET, consisting of high radiation and vapor pressure deficit (D), are often characterized by rainless periods when soil water supply to vegetation may be limiting and plant stomata may close to prevent excessive water loss. In contrast, periods of high ecosystem water availability require frequent precipitation and are characterized by low D. Thus, the combination of these contrasting conditions throughout a growing season may explain some of the consistency in ET. Additionally, vegetation composition is also an important factor in determining ET. In mixed species forests, physiological differences in water use strategies (e.g. isohydric/anisohydric species) can produce conservative water use throughout wet and dry phases of the growing season. Furthermore, transpiration by evergreen specie

  3. Disturbance, complexity, and succession of net ecosystem production in North America’s temperate deciduous forests

    Energy Technology Data Exchange (ETDEWEB)

    Gough, Christopher; Curtis, Peter; Hardiman, Brady; Scheuermann, Cynthia; Bond-Lamberty, Benjamin

    2016-06-29

    Century-old forests in the U.S. upper Midwest and Northeast power much of North Amer- ica’s terrestrial carbon (C) sink, but these forests’ production and C sequestration capacity are expected to soon decline as fast-growing early successional species die and are replaced by slower growing late successional species. But will this really happen? Here we marshal empirical data and ecological theory to argue that substantial declines in net ecosystem production (NEP) owing to reduced forest growth, or net primary production (NPP), are not imminent in regrown temperate deciduous forests over the next several decades. Forest age and production data for temperate deciduous forests, synthesized from published literature, suggest slight declines in NEP and increasing or stable NPP during middle successional stages. We revisit long-held hypotheses by EP Odum and others that suggest low-severity, high-frequency disturbances occurring in the region’s aging forests will, against intuition, maintain NEP at higher-than- expected rates by increasing ecosystem complexity, sustaining or enhancing NPP to a level that largely o sets rising C losses as heterotrophic respiration increases. This theoretical model is also supported by biological evidence and observations from the Forest Accelerated Succession Experiment in Michigan, USA. Ecosystems that experience high-severity disturbances that simplify ecosystem complexity can exhibit substantial declines in production during middle stages of succession. However, observations from these ecosystems have exerted a disproportionate in uence on assumptions regarding the trajectory and magnitude of age-related declines in forest production. We conclude that there is a wide ecological space for forests to maintain NPP and, in doing so, lessens the declines in NEP, with signi cant implications for the future of the North American carbon sink. Our intellectual frameworks for understanding forest C cycle dynamics and resilience need to

  4. Multiple Browsers Structure Tree Recruitment in Logged Temperate Forests.

    Directory of Open Access Journals (Sweden)

    Edward K Faison

    Full Text Available Historical extirpations have resulted in depauperate large herbivore assemblages in many northern forests. In eastern North America, most forests are inhabited by a single wild ungulate species, white-tailed deer (Odocoileus virginianus, and relationships between deer densities and impacts on forest regeneration are correspondingly well documented. Recent recolonizations by moose (Alces americanus in northeastern regions complicate established deer density thresholds and predictions of browsing impacts on forest dynamics because size and foraging differences between the two animals suggest a lack of functional redundancy. We asked to what extent low densities of deer + moose would structure forest communities differently from that of low densities of deer in recently logged patch cuts of Massachusetts, USA. In each site, a randomized block with three treatment levels of large herbivores-no-ungulates (full exclosure, deer (partial exclosure, and deer + moose (control was established. After 6-7 years, deer + moose reduced stem densities and basal area by 2-3-fold, Prunus pensylvanica and Quercus spp. recruitment by 3-6 fold, and species richness by 1.7 species (19%. In contrast, in the partial exclosures, deer had non-significant effects on stem density, basal area, and species composition, but significantly reduced species richness by 2.5 species on average (28%. Deer browsing in the partial exclosure was more selective than deer + moose browsing together, perhaps contributing to the decline in species richness in the former treatment and the lack of additional decline in the latter. Moose used the control plots at roughly the same frequency as deer (as determined by remote camera traps, suggesting that the much larger moose was the dominant browser species in terms of animal biomass in these cuts. A lack of functional redundancy with respect to foraging behavior between sympatric large herbivores may explain combined browsing effects that were

  5. Multiple Browsers Structure Tree Recruitment in Logged Temperate Forests.

    Science.gov (United States)

    Faison, Edward K; DeStefano, Stephen; Foster, David R; Rapp, Joshua M; Compton, Justin A

    2016-01-01

    Historical extirpations have resulted in depauperate large herbivore assemblages in many northern forests. In eastern North America, most forests are inhabited by a single wild ungulate species, white-tailed deer (Odocoileus virginianus), and relationships between deer densities and impacts on forest regeneration are correspondingly well documented. Recent recolonizations by moose (Alces americanus) in northeastern regions complicate established deer density thresholds and predictions of browsing impacts on forest dynamics because size and foraging differences between the two animals suggest a lack of functional redundancy. We asked to what extent low densities of deer + moose would structure forest communities differently from that of low densities of deer in recently logged patch cuts of Massachusetts, USA. In each site, a randomized block with three treatment levels of large herbivores-no-ungulates (full exclosure), deer (partial exclosure), and deer + moose (control) was established. After 6-7 years, deer + moose reduced stem densities and basal area by 2-3-fold, Prunus pensylvanica and Quercus spp. recruitment by 3-6 fold, and species richness by 1.7 species (19%). In contrast, in the partial exclosures, deer had non-significant effects on stem density, basal area, and species composition, but significantly reduced species richness by 2.5 species on average (28%). Deer browsing in the partial exclosure was more selective than deer + moose browsing together, perhaps contributing to the decline in species richness in the former treatment and the lack of additional decline in the latter. Moose used the control plots at roughly the same frequency as deer (as determined by remote camera traps), suggesting that the much larger moose was the dominant browser species in terms of animal biomass in these cuts. A lack of functional redundancy with respect to foraging behavior between sympatric large herbivores may explain combined browsing effects that were both large

  6. Land-use history affects understorey plant species distributions in a large temperate-forest complex, Denmark

    DEFF Research Database (Denmark)

    Svenning, J.-C.; Baktoft, Karen H.; Balslev, Henrik

    2009-01-01

    spatial, and 5 historical variables, and principal components analysis (PCA), redundancy analysis (RDA) as well as indicator species analysis. The historical variables were status as ancient (1805 AD) high forest, reclaimed bogs, ≤100 m from Bronze Age burial mounds, or former conifer plantation...... dispersal and a strong literature record as ancient-forest species, were still concentrated in areas that were high forest in 1805. Among the younger forests, there were clear floristic differences between those on reclaimed bogs and those not. Apparently remnant populations of wet-soil plants were still...

  7. Incidence and effects of endemic populations of forest pests in young mixed-conifer forests of the Sierra Nevada

    Science.gov (United States)

    Carroll B. Williams; David L. Azuma; George T. Ferrell

    1992-01-01

    Approximately 3.200 trees in young mixed-conifer stands were examined for pest activity and human-caused or mechanical injuries, and approximately 25 percent of these trees were randomly selected for stem analyses. The examination of trees felled for stem analyses showed that 409 (47 percent) were free of pests and 466 (53 percent) had one or more pest categories....

  8. Nitrogen Deposition Effects on Soil Carbon Dynamics in Temperate Forests

    DEFF Research Database (Denmark)

    Ginzburg Ozeri, Shimon

    edges were used to study the effects of varying N deposition load on SOC stocks and fluxes as well as on the temperature sensitivity of SOM respiration. In a third study, the effects of 20 years of continuous experimental N addition (35 kg N ha-1 year-1) on soil C budget were investigated. Our general...... incubated in litterbags had significantly lower late-stage decomposition rates compared with control litter. However, potential respiration of forest floor and mineral soil was overall unaffected by the experimental N-additions. A temperature treatment of forest floor samples taken from one edge site......Soils contain the largest fraction of terrestrial carbon (C). Understanding the factors regulating the decomposition and storage of soil organic matter (SOM) is essential for predictions of the C sink strength of the terrestrial environment in the light of global change. Elevated long-term nitrogen...

  9. Maximum temperature accounts for annual soil CO2 efflux in temperate forests of Northern China

    OpenAIRE

    Zhiyong Zhou; Meili Xu; Fengfeng Kang; Osbert Jianxin Sun

    2015-01-01

    It will help understand the representation legality of soil temperature to explore the correlations of soil respiration with variant properties of soil temperature. Soil temperature at 10?cm depth was hourly logged through twelve months. Basing on the measured soil temperature, soil respiration at different temporal scales were calculated using empirical functions for temperate forests. On monthly scale, soil respiration significantly correlated with maximum, minimum, mean and accumulated eff...

  10. Fruit fall in tropical and temperate forests: implications for frugivore diversity

    OpenAIRE

    Hanya, Goro; Aiba, Shin-ichiro

    2010-01-01

    There have been few attempts to compare fruit productivity throughout the world, although this is indispensable for understanding the global variations in frugivore diversity. The purposes of this study are (1) to reveal the patterns in fruit fall in tropical and temperate forests, (2) to examine the environmental factors (location, climate, and total litterfall) affecting these patterns, and (3) to assess the effect of fruit fall on frugivore diversity by using bird and primate data. Fruit f...

  11. Ungulate browsers promote herbaceous layer diversity in logged temperate forests

    Science.gov (United States)

    Faison, Edward K.; DeStefano, Stephen; Foster, David R.; Motzkin, Glenn; Rapp, Josh

    2016-01-01

    Ungulates are leading drivers of plant communities worldwide, with impacts linked to animal density, disturbance and vegetation structure, and site productivity. Many ecosystems have more than one ungulate species; however, few studies have specifically examined the combined effects of two or more species on plant communities. We examined the extent to which two ungulate browsers (moose [Alces americanus]) and white-tailed deer [Odocoileus virginianus]) have additive (compounding) or compensatory (opposing) effects on herbaceous layer composition and diversity, 5–6 years after timber harvest in Massachusetts, USA. We established three combinations of ungulates using two types of fenced exclosures – none (full exclosure), deer (partial exclosure), and deer + moose (control) in six replicated blocks. Species composition diverged among browser treatments, and changes were generally additive. Plant assemblages characteristic of closed canopy forests were less abundant and assemblages characteristic of open/disturbed habitats were more abundant in deer + moose plots compared with ungulate excluded areas. Browsing by deer + moose resulted in greater herbaceous species richness at the plot scale (169 m2) and greater woody species richness at the subplot scale (1 m2) than ungulate exclusion and deer alone. Browsing by deer + moose resulted in strong changes to the composition, structure, and diversity of forest herbaceous layers, relative to areas free of ungulates and areas browed by white-tailed deer alone. Our results provide evidence that moderate browsing in forest openings can promote both herbaceous and woody plant diversity. These results are consistent with the classic grazing-species richness curve, but have rarely been documented in forests.

  12. Mechanisms of nitrogen deposition effects on temperate forest lichens and trees

    Science.gov (United States)

    Carter, Therese S.; Clark, Christopher M.; Fenn, Mark E.; Jovan, Sarah E.; Perakis, Steven; Riddell, Jennifer; Schaberg, Paul G.; Greaver, Tara; Hastings, Meredith

    2017-01-01

    We review the mechanisms of deleterious nitrogen (N) deposition impacts on temperate forests, with a particular focus on trees and lichens. Elevated anthropogenic N deposition to forests has varied effects on individual organisms depending on characteristics both of the N inputs (form, timing, amount) and of the organisms (ecology, physiology) involved. Improved mechanistic knowledge of these effects can aid in developing robust predictions of how organisms respond to either increases or decreases in N deposition. Rising N levels affect forests in micro- and macroscopic ways from physiological responses at the cellular, tissue, and organism levels to influencing individual species and entire communities and ecosystems. A synthesis of these processes forms the basis for the overarching themes of this paper, which focuses on N effects at different levels of biological organization in temperate forests. For lichens, the mechanisms of direct effects of N are relatively well known at cellular, organismal, and community levels, though interactions of N with other stressors merit further research. For trees, effects of N deposition are better understood for N as an acidifying agent than as a nutrient; in both cases, the impacts can reflect direct effects on short time scales and indirect effects mediated through long-term soil and belowground changes. There are many gaps on fundamental N use and cycling in ecosystems, and we highlight the most critical gaps for understanding potential deleterious effects of N deposition. For lichens, these gaps include both how N affects specific metabolic pathways and how N is metabolized. For trees, these gaps include understanding the direct effects of N deposition onto forest canopies, the sensitivity of different tree species and mycorrhizal symbionts to N, the influence of soil properties, and the reversibility of N and acidification effects on plants and soils. Continued study of how these N response mechanisms interact with one

  13. Modelling Vulnerability and Range Shifts in Ant Communities Responding to Future Global Warming in Temperate Forests.

    Science.gov (United States)

    Kwon, Tae-Sung; Li, Fengqing; Kim, Sung-Soo; Chun, Jung Hwa; Park, Young-Seuk

    2016-01-01

    Global warming is likely leading to species' distributional shifts, resulting in changes in local community compositions and diversity patterns. In this study, we applied species distribution models to evaluate the potential impacts of temperature increase on ant communities in Korean temperate forests, by testing hypotheses that 1) the risk of extinction of forest ant species would increase over time, and 2) the changes in species distribution ranges could drive upward movements of ant communities and further alter patterns of species richness. We sampled ant communities at 335 evenly distributed sites across South Korea and modelled the future distribution range for each species using generalized additive models. To account for spatial autocorrelation, autocovariate regressions were conducted prior to generalized additive models. Among 29 common ant species, 12 species were estimated to shrink their suitable geographic areas, whereas five species would benefit from future global warming. Species richness was highest at low altitudes in the current period, and it was projected to be highest at the mid-altitudes in the 2080s, resulting in an upward movement of 4.9 m yr-1. This altered the altitudinal pattern of species richness from a monotonic-decrease curve (common in temperate regions) to a bell-shaped curve (common in tropical regions). Overall, ant communities in temperate forests are vulnerable to the on-going global warming and their altitudinal movements are similar to other faunal communities.

  14. Mapping Aboveground Biomass using Texture Indices from Aerial Photos in a Temperate Forest of Northeastern China

    Directory of Open Access Journals (Sweden)

    Shili Meng

    2016-03-01

    Full Text Available Optical remote sensing data have been considered to display signal saturation phenomena in regions of high aboveground biomass (AGB and multi-storied forest canopies. However, some recent studies using texture indices derived from optical remote sensing data via the Fourier-based textural ordination (FOTO approach have provided promising results without saturation problems for some tropical forests, which tend to underestimate AGB predictions. This study was applied to the temperate mixed forest of the Liangshui National Nature Reserve in Northeastern China and demonstrated the capability of FOTO texture indices to obtain a higher prediction quality of forest AGB. Based on high spatial resolution aerial photos (1.0 m spatial resolution acquired in September 2009, the relationship between FOTO texture indices and field-derived biomass measurements was calibrated using a support vector regression (SVR algorithm. Ten-fold cross-validation was used to construct a robust prediction model, which avoided the over-fitting problem. By further comparison the performance of the model estimates for greater coverage, the predicted results were compared with a reference biomass map derived from LiDAR metrics. This study showed that the FOTO indices accounted for 88.3% of the variance in ground-based AGB; the root mean square error (RMSE was 34.35 t/ha, and RMSE normalized by the mean value of the estimates was 22.31%. This novel texture-based method has great potential for forest AGB estimation in other temperate regions.

  15. Airborne Laser Scanning to support forest resource management under alpine, temperate and Mediterranean environments in Italy

    Directory of Open Access Journals (Sweden)

    Piermaria Corona

    2012-03-01

    Full Text Available This paper aims to provide general considerations, in the form of a scientific review, with reference to selected experiences of ALS applications under alpine, temperate and Mediterranean environments in Italy as case studies. In Italy, the use of ALS data have been mainly focused on the stratification of forest stands and the estimation of their timber volume and biomass at local scale. Potential for ALS data exploitation concerns their integration in forest inventories on large territories, their usage for silvicultural systems detection and their use for the estimation of fuel load in forest and pre-forest stands. Multitemporal ALS may even be suitable to support the assessment of current annual volume increment and the harvesting rates.

  16. Leaf litter dynamics and litter consumption in two temperate South Australian mangrove forests

    Science.gov (United States)

    Imgraben, Sarah; Dittmann, Sabine

    2008-02-01

    The dynamics and consumption of mangrove litter were investigated in two temperate Avicennia marina dominated forests in South Australia in order to compare production and fate of leaf litter with records from tropical and temperate mangroves. Litterfall was measured using traps over four months in the summer of 2004/2005. Average amount of litter was 2.1 and 3.2 g dwt m - 2 d - 1 , respectively, at the two study sites. Leaves accounted for most of the litterfall, followed by propagules and wood. Litterfall varied over time, and depending on the site and inundation time. The standing stock of leaf litter on the forest floor amounted to 15.5 g m - 2 dwt in March 2005. Decomposition determined by litter bags suggested that leaves lost ˜ 50% of their weight in the first two weeks of exposure, with little further weight loss over longer exposure times. Leaf consumption was investigated with a series of laboratory experiments, using the grapsid crab Helograpsus haswellianus, two snail species ( Salinator fragilis and Austrocochlea concamerata) and the polychaete Neanthes vaalii as potential consumers. There was no consumption of new leaves, and the only significant consumption of aged leaves was found for female H. haswellianus. H. haswellianus consumed 0.1 g dwt d - 1 of senescent leaves in the experiment, equivalent to 0.18 g m - 2 d - 1 in the field (average crab density 1.8 ind m - 2 ), or 9.4% of the average daily leaf litterfall. Experiments with propagules revealed no significant consumption by the crabs. High decomposition and low consumption rates of crabs account for the high accumulation and possible export of leaf litter from these mangroves. Leaf litter availability is not a limiting factor for invertebrate consumers in these temperate mangrove forests, and the low consumption rates imply a major difference in the fate of leaf litter between tropical and temperate mangrove systems.

  17. The impact of forest roads on understory plant diversity in temperate hornbeam-beech forests of Northern Iran.

    Science.gov (United States)

    Deljouei, Azade; Abdi, Ehsan; Marcantonio, Matteo; Majnounian, Baris; Amici, Valerio; Sohrabi, Hormoz

    2017-08-01

    Forest roads alter the biotic and abiotic components of ecosystems, modifying temperature, humidity, wind speed, and light availability that, in turn, cause changes in plant community composition and diversity. We aim at investigating and comparing the diversity of herbaceous species along main and secondary forest roads in a temperate-managed hornbeam-beech forest, north of Iran. Sixteen transects along main and secondary forest roads were established (eight transects along main roads and eight along secondary roads). To eliminate the effect of forest type, all transects were located in Carpinetum-Fagetum forests, the dominant forest type in the study area. The total length of each transect was 200 m (100 m toward up slope and 100 m toward down slope), and plots were established along it at different distances from road edge. The diversity of herbaceous plant species was calculated in each plot using Shannon-Wiener index, species richness, and Pielou's index. The results showed that diversity index decreased when distance from road edge increases. This decreasing trend continued up to 60 m from forest road margin, and after this threshold, the index slightly increased. Depending on the type of road (main or secondary) as well as cut or fill slopes, the area showing a statistical different plant composition and diversity measured through Shannon-Wiener, species richness, and Pielou's index is up to 10 m. The length depth of the road edge effect found in main and secondary forest roads was small, but it could have cumulative effects on forest microclimate and forest-associated biota at the island scale. Forest managers should account for the effect of road buildings on plant communities.

  18. Temperate and boreal forest mega-fires: characteristics and challenges

    Science.gov (United States)

    Stephens, Scott L.; Burrows, Neil; Buyantuyev, Alexander; Gray, Robert W.; Keane, Robert E.; Kubian, Rick; Liu, Shirong; Seijo, Francisco; Shu, Lifu; Tolhurst, Kevin G.; Van Wagtendonk, Jan W.

    2014-01-01

    Mega-fires are often defined according to their size and intensity but are more accurately described by their socioeconomic impacts. Three factors – climate change, fire exclusion, and antecedent disturbance, collectively referred to as the “mega-fire triangle” – likely contribute to today's mega-fires. Some characteristics of mega-fires may emulate historical fire regimes and can therefore sustain healthy fire-prone ecosystems, but other attributes decrease ecosystem resiliency. A good example of a program that seeks to mitigate mega-fires is located in Western Australia, where prescribed burning reduces wildfire intensity while conserving ecosystems. Crown-fire-adapted ecosystems are likely at higher risk of frequent mega-fires as a result of climate change, as compared with other ecosystems once subject to frequent less severe fires. Fire and forest managers should recognize that mega-fires will be a part of future wildland fire regimes and should develop strategies to reduce their undesired impacts.

  19. Rapid Deposition of Oxidized Biogenic Compounds to a Temperate Forest

    Science.gov (United States)

    Nguyen, Tran B.; Crounse, John D.; Teng, Alex P.; St. Clair, Jason M.; Paulot, Fabien; Wolfe, Glenn M.; Wennberg, Paul O.

    2015-01-01

    We report fluxes and dry deposition velocities for 16 atmospheric compounds above a southeastern United States forest, including: hydrogen peroxide (H2O2), nitric acid (HNO3), hydrogen cyanide (HCN), hydroxymethyl hydroperoxide, peroxyacetic acid, organic hydroxy nitrates, and other multifunctional species derived from the oxidation of isoprene and monoterpenes. The data suggest that dry deposition is the dominant daytime sink for small, saturated oxygenates. Greater than 6 wt %C emitted as isoprene by the forest was returned by dry deposition of its oxidized products. Peroxides account for a large fraction of the oxidant flux, possibly eclipsing ozone in more pristine regions. The measured organic nitrates comprise a sizable portion (15%) of the oxidized nitrogen input into the canopy, with HNO3 making up the balance. We observe that water-soluble compounds (e.g., strong acids and hydroperoxides) deposit with low surface resistance whereas compounds with moderate solubility (e.g., organic nitrates and hydroxycarbonyls) or poor solubility (e.g., HCN) exhibited reduced uptake at the surface of plants. To first order, the relative deposition velocities of water-soluble compounds are constrained by their molecular diffusivity. From resistance modeling, we infer a substantial emission flux of formic acid at the canopy level (approx. 1 nmol m(exp.-2)·s(exp.-1)). GEOS-Chem, awidely used atmospheric chemical transport model, currently underestimates dry deposition for most molecules studied in this work. Reconciling GEOS-Chem deposition velocities with observations resulted in up to a 45% decrease in the simulated surface concentration of trace gases.

  20. Altitudinal variation of soil organic carbon stocks in temperate forests of Kashmir Himalayas, India.

    Science.gov (United States)

    Ahmad Dar, Javid; Somaiah, Sundarapandian

    2015-02-01

    Soil organic carbon stocks were measured at three depths (0-10, 10-20, and 20-30 cm) in seven altitudes dominated by different forest types viz. Populus deltoides, 1550-1800 m; Juglans regia, 1800-2000 m; Cedrus deodara, 2050-2300 m; Pinus wallichiana, 2000-2300 m; mixed type, 2200-2400 m; Abies pindrow, 2300-2800 m; and Betula utilis, 2800-3200 m in temperate mountains of Kashmir Himalayas. The mean range of soil organic carbon (SOC) stocks varied from 39.07 to 91.39 Mg C ha(-1) in J. regia and B. utilis forests at 0-30 cm depth, respectively. Among the forest types, the lowest mean range of SOC at three depths (0-10, 10-20, and 20-30 cm) was observed in J. regia (18.55, 11.31, and 8.91 Mg C ha(-1), respectively) forest type, and the highest was observed in B. utilis (54.10, 21.68, and 15.60 Mg C ha(-1), respectively) forest type. SOC stocks showed significantly (R (2) = 0.67, P = 0.001) an increasing trend with increase in altitude. On average, the percentages of SOC at 0-10-, 10-20-, and 20-30-cm depths were 53.2, 26.5, and 20.3 %, respectively. Bulk density increased significantly with increase in soil depth and decreased with increase in altitude. Our results suggest that SOC stocks in temperate forests of Kashmir Himalaya vary greatly with forest type and altitude. The present study reveals that SOC stocks increased with increase in altitude at high mountainous regions. Climate change in these high mountainous regions will alter the carbon sequestration potential, which would affect the global carbon cycle.

  1. Land use strategies to mitigate climate change in carbon dense temperate forests.

    Science.gov (United States)

    Law, Beverly E; Hudiburg, Tara W; Berner, Logan T; Kent, Jeffrey J; Buotte, Polly C; Harmon, Mark E

    2018-03-19

    Strategies to mitigate carbon dioxide emissions through forestry activities have been proposed, but ecosystem process-based integration of climate change, enhanced CO 2 , disturbance from fire, and management actions at regional scales are extremely limited. Here, we examine the relative merits of afforestation, reforestation, management changes, and harvest residue bioenergy use in the Pacific Northwest. This region represents some of the highest carbon density forests in the world, which can store carbon in trees for 800 y or more. Oregon's net ecosystem carbon balance (NECB) was equivalent to 72% of total emissions in 2011-2015. By 2100, simulations show increased net carbon uptake with little change in wildfires. Reforestation, afforestation, lengthened harvest cycles on private lands, and restricting harvest on public lands increase NECB 56% by 2100, with the latter two actions contributing the most. Resultant cobenefits included water availability and biodiversity, primarily from increased forest area, age, and species diversity. Converting 127,000 ha of irrigated grass crops to native forests could decrease irrigation demand by 233 billion m 3 ⋅y -1 Utilizing harvest residues for bioenergy production instead of leaving them in forests to decompose increased emissions in the short-term (50 y), reducing mitigation effectiveness. Increasing forest carbon on public lands reduced emissions compared with storage in wood products because the residence time is more than twice that of wood products. Hence, temperate forests with high carbon densities and lower vulnerability to mortality have substantial potential for reducing forest sector emissions. Our analysis framework provides a template for assessments in other temperate regions. Copyright © 2018 the Author(s). Published by PNAS.

  2. Aboveground-belowground biodiversity linkages differ in early and late successional temperate forests.

    Science.gov (United States)

    Li, Hui; Wang, Xugao; Liang, Chao; Hao, Zhanqing; Zhou, Lisha; Ma, Sam; Li, Xiaobin; Yang, Shan; Yao, Fei; Jiang, Yong

    2015-07-17

    Understanding ecological linkages between above- and below-ground biota is critical for deepening our knowledge on the maintenance and stability of ecosystem processes. Nevertheless, direct comparisons of plant-microbe diversity at the community level remain scarce due to the knowledge gap between microbial ecology and plant ecology. We compared the α- and β- diversities of plant and soil bacterial communities in two temperate forests that represented early and late successional stages. We documented different patterns of aboveground-belowground diversity relationships in these forests. We observed no linkage between plant and bacterial α-diversity in the early successional forest, and even a negative correlation in the late successional forest, indicating that high bacterial α-diversity is not always linked to high plant α-diversity. Beta-diversity coupling was only found at the late successional stage, while in the early successional forest, the bacterial β-diversity was closely correlated with soil property distances. Additionally, we showed that the dominant competitive tree species in the late successional forest may play key roles in driving forest succession by shaping the soil bacterial community in the early successional stage. This study sheds new light on the potential aboveground-belowground linkage in natural ecosystems, which may help us understand the mechanisms that drive ecosystem succession.

  3. Short- and long-term effects of fire on carbon in US dry temperate forest systems

    Science.gov (United States)

    Hurteau, Matthew D.; Brooks, Matthew L.

    2011-01-01

    Forests sequester carbon from the atmosphere, and in so doing can mitigate the effects of climate change. Fire is a natural disturbance process in many forest systems that releases carbon back to the atmosphere. In dry temperate forests, fires historically burned with greater frequency and lower severity than they do today. Frequent fires consumed fuels on the forest floor and maintained open stand structures. Fire suppression has resulted in increased understory fuel loads and tree density; a change in structure that has caused a shift from low- to high-severity fires. More severe fires, resulting in greater tree mortality, have caused a decrease in forest carbon stability. Fire management actions can mitigate the risk of high-severity fires, but these actions often require a trade-off between maximizing carbon stocks and carbon stability. We discuss the effects of fire on forest carbon stocks and recommend that managing forests on the basis of their specific ecologies should be the foremost goal, with carbon sequestration being an ancillary benefit. ?? 2011 by American Institute of Biological Sciences. All rights reserved.

  4. Long-term variability in the water budget and its controls in an oak-dominated temperate forest

    Science.gov (United States)

    Jing Xie; Ge Sun; Hou-Sen Chu; Junguo Liu; Steven G. McNulty; Asko Noormets; Ranjeet John; Zutao Ouyang; Tianshan Zha; Haitao Li; Wenbin Guan; Jiquan Chen

    2014-01-01

    Water availability is one of the key environmental factors that control ecosystem functions in temperate forests. Changing climate is likely to alter the ecohydrology and other ecosystem processes, which affect forest structures and functions. We constructed a multi-year water budget (2004–2010) and quantified environmental controls on an evapotranspiration (ET) in a...

  5. Subantarctic forest ecology : case study of a conifer-broadleaved stand in Patagonia, Argentina

    NARCIS (Netherlands)

    Dezzotti, A.

    2000-01-01

    In the temperate rainforests of southern South America, the tree genus Nothofagus (Nothofagaceae) is the dominant in extension and abundance on zonal soils at different latitudes and altitudes, as well as on intrazonal (e.g., wetlands) and azonal soils (e.g., morrenic

  6. Regeneration complexities of Pinus gerardiana in dry temperate forests of Indian Himalaya.

    Science.gov (United States)

    Kumar, Raj; Shamet, G S; Mehta, Harsh; Alam, N M; Kaushal, Rajesh; Chaturvedi, O P; Sharma, Navneet; Khaki, B A; Gupta, Dinesh

    2016-04-01

    Pinus gerardiana is considered an important species in dry temperate forests of North-Western Indian Himalaya because of its influence on ecological processes and economic dependence of local people in the region. But, large numbers of biotic and abiotic factors have affected P. gerardiana in these forests; hence, there is a crucial need to understand the regeneration dynamics of this tree species. The present investigation was conducted in P. gerardiana forests to understand vegetation pattern and regeneration processes on different sites in the region. Statistical analysis was performed to know variability in growing stock and regeneration on sample plots, while correlation coefficients and regression models were developed to find the relationship between regeneration and site factors. The vegetation study showed dominance of P. gerardiana, which is followed by Cedrus deodara, Pinus wallichiana and Quercus ilex in the region. The growing stock of P. gerardiana showed steep increasing and then steadily declining trend from lower to higher diameter class. The distribution of seedling, sapling, pole and trees was not uniform at different sites and less number of plots in each site were observed to have effective conditions for continuous regeneration, but mostly showed extremely limited regeneration. Regeneration success ranging from 8.44 to 15.93 % was recorded in different sites of the region, which suggests that in different sites regeneration success is influenced by collection of cone for extracting seed, grazing/browsing and physico-chemical properties of soil. Regeneration success showed significant correlation and relationship with most of abiotic and biotic factors. The regeneration success is lower than the requirement of sustainable forest, but varies widely among sites in dry temperate forests of Himalaya. More forest surveys are required to understand the conditions necessary for greater success of P. gerardiana in the region.

  7. Topographic variation in structure of mixed-conifer forests under an active-fire regime

    Science.gov (United States)

    Jamie Lydersen; Malcolm North

    2012-01-01

    Management efforts to promote forest resiliency as climate changes have often used historical forest conditions to provide general guidance for fuels reduction and forest restoration treatments. However, it has been difficult to identify what stand conditions might be fire and drought resilient because historical data and reconstruction studies are generally limited to...

  8. Factors affecting distribution of wood, detritus, and sediment in headwater streams draining managed young-growth red alder - Conifer forests in southeast Alaska

    Science.gov (United States)

    Gomi, T.; Johnson, A.C.; Deal, R.L.; Hennon, P.E.; Orlikowska, E.H.; Wipfli, M.S.

    2006-01-01

    Factors (riparian stand condition, management regimes, and channel properties) affecting distributions of wood, detritus (leaves and branches), and sediment were examined in headwater streams draining young-growth red alder (Alnus rubra Bong.) - conifer riparian forests (40 years old) remained in channels and provided sites for sediment and organic matter storage. Despite various alder-conifer mixtures and past harvesting effects, the abundance of large wood, fine wood, and detritus accumulations significantly decreased with increasing channel bank-full width (0.5-3.5 m) along relatively short channel distances (up to 700 m). Changes in wood, detritus, and sediment accumulations together with changes in riparian stand characteristics create spatial and temporal variability of in-channel conditions in headwater systems. A component of alder within young-growth riparian forests may benefit both wood production and biological recovery in disturbed headwater stream channels. ?? 2006 NRC.

  9. Carbon storage versus albedo change: Radiative Forcing of forest expansion in temperate mountainous regions of Switzerland

    Science.gov (United States)

    Schwaab, J.; Bavay, M.; Davin, E.; Hagedorn, F.; Hüsler, F.; Lehning, M.; Schneebeli, M.; Thürig, E.; Bebi, P.

    2014-06-01

    Forestation is seen as a possible option to counter climate change by sequestering carbon in forests and thus reducing the atmospheric concentration of carbon dioxide. However, previous studies suggest that the Radiative Forcing (RF) caused by forestation-induced albedo change in snow-rich boreal regions may offset the carbon sequestration effect. The Swiss mountains are characterized by snow-rich areas with strongly varying environmental conditions and forest expansion is currently the dominant land-use change process. Thus, quantifying both carbon sequestration and albedo change on appropriately high resolution in this region will improve our understanding of the forests potential for climate mitigation. We calculated the albedo RF based on remotely sensed datasets of albedo, global radiation and snow cover. Carbon sequestration was estimated from changes in carbon stocks based on National Inventories. Our results show that the net RF of forest expansion ranges from -24 W m-2 at low elevations of the Northern Prealps to 2 W m-2 at high elevations of the Central Alps. The albedo RF increases with increasing altitude, which offsets the CO2 RF at high elevations with long snow-covered periods, high global radiation and low carbon sequestration. Results indicate that the albedo RF is particularly relevant during transitions from open land to open forest and not in later stages of forest development. The albedo RF offsets the CO2 RF by an average of 40% between 1985 and 1997 when overall forest expansion in Switzerland was approximately 4%. We conclude that the albedo RF should be considered at an appropriately high resolution when estimating the climatic effect of forestation in temperate mountainous regions.

  10. Conifer seedling recruitment across a gradient from forest to alpine tundra: effects of species, provenance, and site

    Science.gov (United States)

    Castanha, C.; Torn, M.S.; Germino, M.J.; Weibel, Bettina; Kueppers, L.M.

    2013-01-01

    Background: Seedling germination and survival is a critical control on forest ecosystem boundaries, such as at the alpine–treeline ecotone. In addition, while it is known that species respond individualistically to the same suite of environmental drivers, the potential additional effect of local adaptation on seedling success has not been evaluated. Aims: To determine whether local adaptation may influence the position and movement of forest ecosystem boundaries, we quantified conifer seedling recruitment in common gardens across a subalpine forest to alpine tundra gradient at Niwot Ridge, Colorado, USA. Methods: We studied Pinus flexilis and Picea engelmannii grown from seed collected locally at High (3400 m a.s.l.) and Low (3060 m a.s.l.) elevations. We monitored emergence and survival of seeds sown directly into plots and survival of seedlings germinated indoors and transplanted after snowmelt. Results: Emergence and survival through the first growing season was greater for P. flexilis than P. engelmannii and for Low compared with High provenances. Yet survival through the second growing season was similar for both species and provenances. Seedling emergence and survival tended to be greatest in the subalpine forest and lowest in the alpine tundra. Survival was greater for transplants than for field-germinated seedlings. Conclusions: These results suggest that survival through the first few weeks is critical to the establishment of natural germinants. In addition, even small distances between seed sources can have a significant effect on early demographic performance – a factor that has rarely been considered in previous studies of tree recruitment and species range shifts.

  11. Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA

    Science.gov (United States)

    Jenkins, S.E.; Hull, Sieg C.; Anderson, D.E.; Kaufman, D.S.; Pearthree, P.A.

    2011-01-01

    Long-term fire history reconstructions enhance our understanding of fire behaviour and associated geomorphic hazards in forested ecosystems. We used 14C ages on charcoal from fire-induced debris-flow deposits to date prehistoric fires on Kendrick Mountain, northern Arizona, USA. Fire-related debris-flow sedimentation dominates Holocene fan deposition in the study area. Radiocarbon ages indicate that stand-replacing fire has been an important phenomenon in late Holocene ponderosa pine (Pinus ponderosa) and ponderosa pine-mixed conifer forests on steep slopes. Fires have occurred on centennial scales during this period, although temporal hiatuses between recorded fires vary widely and appear to have decreased during the past 2000 years. Steep slopes and complex terrain may be responsible for localised crown fire behaviour through preheating by vertical fuel arrangement and accumulation of excessive fuels. Holocene wildfire-induced debris flow events occurred without a clear relationship to regional climatic shifts (decadal to millennial), suggesting that interannual moisture variability may determine fire year. Fire-debris flow sequences are recorded when (1) sufficient time has passed (centuries) to accumulate fuels; and (2) stored sediment is available to support debris flows. The frequency of reconstructed debris flows should be considered a minimum for severe events in the study area, as fuel production may outpace sediment storage. ?? IAWF 2011.

  12. Estimating canopy bulk density and canopy base height for conifer stands in the interior Western United States using the Forest Vegetation Simulator Fire and Fuels Extension.

    Science.gov (United States)

    Seth Ex; Frederick Smith; Tara Keyser; Stephanie Rebain

    2017-01-01

    The Forest Vegetation Simulator Fire and Fuels Extension (FFE-FVS) is often used to estimate canopy bulk density (CBD) and canopy base height (CBH), which are key indicators of crown fire hazard for conifer stands in the Western United States. Estimated CBD from FFE-FVS is calculated as the maximum 4 m running mean bulk density of predefined 0.3 m thick canopy layers (...

  13. Adaptive root foraging strategies along a boreal-temperate forest gradient.

    Science.gov (United States)

    Ostonen, Ivika; Truu, Marika; Helmisaari, Heljä-Sisko; Lukac, Martin; Borken, Werner; Vanguelova, Elena; Godbold, Douglas L; Lõhmus, Krista; Zang, Ulrich; Tedersoo, Leho; Preem, Jens-Konrad; Rosenvald, Katrin; Aosaar, Jürgen; Armolaitis, Kęstutis; Frey, Jane; Kabral, Naima; Kukumägi, Mai; Leppälammi-Kujansuu, Jaana; Lindroos, Antti-Jussi; Merilä, Päivi; Napa, Ülle; Nöjd, Pekka; Parts, Kaarin; Uri, Veiko; Varik, Mats; Truu, Jaak

    2017-08-01

    The tree root-mycorhizosphere plays a key role in resource uptake, but also in the adaptation of forests to changing environments. The adaptive foraging mechanisms of ectomycorrhizal (EcM) and fine roots of Picea abies, Pinus sylvestris and Betula pendula were evaluated along a gradient from temperate to subarctic boreal forest (38 sites between latitudes 48°N and 69°N) in Europe. Variables describing tree resource uptake structures and processes (absorptive fine root biomass and morphology, nitrogen (N) concentration in absorptive roots, extramatrical mycelium (EMM) biomass, community structure of root-associated EcM fungi, soil and rhizosphere bacteria) were used to analyse relationships between root system functional traits and climate, soil and stand characteristics. Absorptive fine root biomass per stand basal area increased significantly from temperate to boreal forests, coinciding with longer and thinner root tips with higher tissue density, smaller EMM biomass per root length and a shift in soil microbial community structure. The soil carbon (C) : N ratio was found to explain most of the variability in absorptive fine root and EMM biomass, root tissue density, N concentration and rhizosphere bacterial community structure. We suggest a concept of absorptive fine root foraging strategies involving both qualitative and quantitative changes in the root-mycorrhiza-bacteria continuum along climate and soil C : N gradients. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  14. Detection of photosynthetic responses of cool-temperate forests following extreme climate events using Bayesian inversion

    Science.gov (United States)

    Toda, M.; Knohl, A.; Herbst, M.; Keenan, T. F.; Yokozawa, M.

    2016-12-01

    The increase in extreme climate events associated with ongoing global warming may create severe damage to terrestrial ecosystems, changing plant structure and the eco-physiological functions that regulate ecosystem carbon exchange. However, most damage is usually due to moderate, rather than catastrophic, disturbances. The nature of plant functional responses to such disturbances, and the resulting effects on the terrestrial carbon cycle, remain poorly understood. To unravel the scientific question, tower-based eddy covariance data in the cool-temperate forests were used to constrain plant eco-physiological parameters in a persimoneous ecosystem model that may have affected carbon dynamics following extreme climate events using the statistic Bayesian inversion approach. In the present study, we raised two types of extreme events relevant for cool-temperate regions, i.e. a typhoon with mechanistic foliage destraction and a heat wave with severe drought. With appropriate evaluation of parameter and predictive uncertainties, the inversion analysis shows annual trajectory of activated photosynthetic responses following climate extremes compared the pre-disturbance state in each forest. We address that forests with moderate disturbance show substantial and rapid photosynthetic recovery, enhanced productivity, and, thus, ecosystem carbon exchange, although the effect of extreme climatic events varies depending on the stand successional phase and the type, intensity, timing and legacy of the disturbance.

  15. Influence of spring phenology on seasonal and annual carbon balance in two contrasting New England forests

    Science.gov (United States)

    Andrew D. Richardson; David Y. Hollinger; D. Bryan Dail; John T. Lee; J. William Munger; John O' Keefe

    2009-01-01

    Spring phenology is thought to exert a major influence on the carbon (C) balance of temperate and boreal ecosystems. We investigated this hypothesis using four spring onset phenological indicators in conjunction with surface-atmosphere CO2 exchange data from the conifer-dominated Howland Forest and deciduous-dominated Harvard Forest AmeriFlux...

  16. Litterfall production and fine root dynamics in cool-temperate forests.

    Science.gov (United States)

    An, Ji Young; Park, Byung Bae; Chun, Jung Hwa; Osawa, Akira

    2017-01-01

    Current understanding of litterfall and fine root dynamics in temperate forests is limited, even though these are the major contributors to carbon and nutrient cycling in the ecosystems. In this study, we investigated litterfall and fine root biomass and production in five deciduous and four coniferous forests at the Gwangneung Experimental Forest in Korea. We used ingrowth cores to measure fine root production and root turnover rate. The litterfall was separated into leaves, twigs, and others, and then leaves were further separated according to species. Annual litterfall mass was not significantly different between the years, 360 to 651 g m-2 in 2011 and 300 to 656 g m-2 in 2012. Annual fine root (forests and 1.97 for coniferous forests. Fine root production constituted 18-44% of NPP, where NPP was the sum of woody biomass production, litterfall production, and fine root production. Belowground production was a greater fraction of NPP in more productive forests suggesting their greater carbon allocation belowground.

  17. Maximum temperature accounts for annual soil CO2 efflux in temperate forests of Northern China.

    Science.gov (United States)

    Zhou, Zhiyong; Xu, Meili; Kang, Fengfeng; Jianxin Sun, Osbert

    2015-07-16

    It will help understand the representation legality of soil temperature to explore the correlations of soil respiration with variant properties of soil temperature. Soil temperature at 10 cm depth was hourly logged through twelve months. Basing on the measured soil temperature, soil respiration at different temporal scales were calculated using empirical functions for temperate forests. On monthly scale, soil respiration significantly correlated with maximum, minimum, mean and accumulated effective soil temperatures. Annual soil respiration varied from 409 g C m(-2) in coniferous forest to 570 g C m(-2) in mixed forest and to 692 g C m(-2) in broadleaved forest, and was markedly explained by mean soil temperatures of the warmest day, July and summer, separately. These three soil temperatures reflected the maximum values on diurnal, monthly and annual scales. In accordance with their higher temperatures, summer soil respiration accounted for 51% of annual soil respiration across forest types, and broadleaved forest also had higher soil organic carbon content (SOC) and soil microbial biomass carbon content (SMBC), but a lower contribution of SMBC to SOC. This added proof to the findings that maximum soil temperature may accelerate the transformation of SOC to CO2-C via stimulating activities of soil microorganisms.

  18. Fire suppression has led to greater drought-sensitivity in dry conifer forests: tree-ring carbon isotope evidence from Central Oregon

    Science.gov (United States)

    Voelker, S.; Merschel, A. G.; Meinzer, F. C.; Spies, T. A.; Still, C. J.

    2016-12-01

    Mortality events of economically and ecologically important conifers have been widespread across Western North America over recent decades. Many of these events have been linked to "global change-type droughts" characterized by greater temperatures and evaporative demand. In parallel, since the early to mid- 20th century, increasing atmospheric [CO2] has been shown to increase the water use efficiency (WUE) of trees worldwide while conifer forests in western North America have become denser after the advent of modern fire suppression efforts. Therefore, competing hypotheses include that conifer forests have experienced 1) less drought stress due to water savings from increased WUE, 2) more drought stress due to increased demand for water in dense forests with greater leaf area index, or 3) unchanging stress because these two factors have cancelled each other out. To provide a test of these hypotheses we used inter-annual latewood carbon isotope discrimination, Δ13C, across a dry mixed-conifer forest landscape of central Oregon in the rain shadow of the Cascade Mountains. The forests are dominated by old-growth ponderosa pines (Pinus ponderosa) and younger and fire-intolerant grand firs (Abies grandis). Dendrochronological dating of tree establishment and fires scars established sharp declines in fire frequency and associated increases in the densities of grand fir since the early 1900s. Δ13C data for ponderosa pine and grand fir spanned 1830-2013 and 1900-2013, respectively. For our analyses these years were split into periods of high fire frequency (1830-1900), moderate fire frequency (1901-1956) and fire-exclusion (1957-2013). Comparisons of Δ13C to reconstructed Palmer Drought Severity Index values for the same years revealed that leaf gas exchange of both species has been more sensitive to drought during the recent fire-exclusion period compared to previous periods when surface fires kept tree densities much lower. Similar research is needed elsewhere to

  19. Adaptive root foraging strategies along a boreal–temperate forest gradient

    Czech Academy of Sciences Publication Activity Database

    Ostonen, I.; Truu, M.; Helmisaari, H.-S.; Lukač, M.; Borken, W.; Vanguelova, H.; Godbold, Douglas; Löhmus, K.; Zang, U.; Tedersoo, L.; Preem, J.-K.; Rosenvald, K.; Aosaar, J.; Armolaitis, K.; Frey, J.; Kabral, N.; Kukumägi, M.; Leppälammi-Kujansuu, J.; Lindroos, A.-J.; Merila, P.; Napa, Ü.; Nöjd, P.; Parts, K.; Uri, V.; Varik, M.; Truu, J.

    2017-01-01

    Roč. 215, č. 3 (2017), s. 977-991 ISSN 0028-646X EU Projects: European Commission(XE) 315982; European Commission(XE) 315982; European Commission(XE) 90/E38 Institutional support: RVO:67179843 Keywords : boreal and temperate forests * climate gradient * ectomycorrhizal (EcM) mycelium * fine and ectomycorrhizal root biomass * root foraging * root morphology * soil and rhizosphere bacteria * soil C * N ratio Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 7.330, year: 2016

  20. Complementary models of tree species-soil relationships in old-growth temperate forests

    Science.gov (United States)

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    context-dependent tree species-soil relationships occur simultaneouslyinold-grow the temperate forests, with context-dependent relationships strongest for organically cycled elements, and site-independent relationships strongest for weather able elements with in organic cycling phases. These models provide complementary explanations for patterns of nutrient accumulation and cycling in mixed species old-growth temperate forests.

  1. Diversity patterns of ground beetles and understory vegetation in mature, secondary, and plantation forest regions of temperate northern China.

    Science.gov (United States)

    Zou, Yi; Sang, Weiguo; Wang, Shunzhong; Warren-Thomas, Eleanor; Liu, Yunhui; Yu, Zhenrong; Wang, Changliu; Axmacher, Jan Christoph

    2015-02-01

    Plantation and secondary forests form increasingly important components of the global forest cover, but our current knowledge about their potential contribution to biodiversity conservation is limited. We surveyed understory plant and carabid species assemblages at three distinct regions in temperate northeastern China, dominated by mature forest (Changbaishan Nature Reserve, sampled in 2011 and 2012), secondary forest (Dongling Mountain, sampled in 2011 and 2012), and forest plantation habitats (Bashang Plateau, sampled in 2006 and 2007), respectively. The α-diversity of both taxonomic groups was highest in plantation forests of the Bashang Plateau. Beetle α-diversity was lowest, but plant and beetle species turnover peaked in the secondary forests of Dongling Mountain, while habitats in the Changbaishan Nature Reserve showed the lowest turnover rates for both taxa. Changbaishan Nature Reserve harbored the highest proportion of forest specialists. Our results suggest that in temperate regions of northern China, the protected larch plantation forest established over extensive areas might play a considerable role in maintaining a high biodiversity in relation to understory herbaceous plant species and carabid assemblages, which can be seen as indicators of forest disturbance. The high proportion of phytophagous carabids and the rarity of forest specialists reflect the relatively homogenous, immature status of the forest ecosystems on the Bashang Plateau. China's last remaining large old-growth forests like the ones on Changbaishan represent stable, mature ecosystems which require particular conservation attention.

  2. Temperate and boreal old-growth forests: how do their growth dynamics and biodiversity differ from young stands and managed forests?

    NARCIS (Netherlands)

    Schulze, E.D.; Hessenmoeller, D; Knohl, A.; Luyssaert, S; Boerner, A; Grace, J.

    2009-01-01

    This chapter investigates biomass, net primary productivity (NPP), and net ecosystem productivity (NEP) of boreal and temperate forest ecosystems in relation to stand density and age. Forests may accumulate woody biomass at constant rate for centuries and there is little evidence of an age-related

  3. The formation and fate of chlorinated organic substances in temperate and boreal forest soils.

    Science.gov (United States)

    Clarke, Nicholas; Fuksová, Kvetoslava; Gryndler, Milan; Lachmanová, Zora; Liste, Hans-Holger; Rohlenová, Jana; Schroll, Reiner; Schröder, Peter; Matucha, Miroslav

    2009-03-01

    Chlorine is an abundant element, commonly occurring in nature either as chloride ions or as chlorinated organic compounds (OCls). Chlorinated organic substances were long considered purely anthropogenic products; however, they are, in addition, a commonly occurring and important part of natural ecosystems. Formation of OCls may affect the degradation of soil organic matter (SOM) and thus the carbon cycle with implications for the ability of forest soils to sequester carbon, whilst the occurrence of potentially toxic OCls in groundwater aquifers is of concern with regard to water quality. It is thus important to understand the biogeochemical cycle of chlorine, both inorganic and organic, to get information about the relevant processes in the forest ecosystem and the effects on these from human activities, including forestry practices. A survey is given of processes in the soil of temperate and boreal forests, predominantly in Europe, including the participation of chlorine, and gaps in knowledge and the need for further work are discussed. Chlorine is present as chloride ion and/or OCls in all compartments of temperate and boreal forest ecosystems. It contributes to the degradation of SOM, thus also affecting carbon sequestration in the forest soil. The most important source of chloride to coastal forest ecosystems is sea salt deposition, and volcanoes and coal burning can also be important sources. Locally, de-icing salt can be an important chloride input near major roads. In addition, anthropogenic sources of OCls are manifold. However, results also indicate the formation of chlorinated organics by microorganisms as an important source, together with natural abiotic formation. In fact, the soil pool of OCls seems to be a result of the balance between chlorination and degradation processes. Ecologically, organochlorines may function as antibiotics, signal substances and energy equivalents, in descending order of significance. Forest management practices can affect

  4. Functional and phylogenetic diversity determine woody productivity in a temperate forest.

    Science.gov (United States)

    Hao, MinHui; Zhang, Chunyu; Zhao, Xiuhai; von Gadow, Klaus

    2018-03-01

    Understanding the relationships between biodiversity and ecosystem productivity has become a central issue in ecology and conservation biology studies, particularly when these relationships are connected with global climate change and species extinction. However, which facets of biodiversity (i.e. taxonomic, functional, and phylogenetic diversity) account most for variations in productivity are still not understood very well. This is especially true with regard to temperate forest ecosystems. In this study, we used a dataset from a stem-mapped permanent forest plot in northeastern China exploring the relationships between biodiversity and productivity at different spatial scales (20 × 20 m; 40 × 40 m; and 60 × 60 m). The influence of specific environmental conditions (topographic conditions) and stand maturity (expressed by initial stand volume and biomass) were taken into account using the multivariate approach known as structural equation models. The variable "Biodiversity" includes taxonomic (Shannon), functional (FDis), and phylogenetic diversity (PD). Biodiversity-productivity relationships varied with the spatial scales. At the scale of 20 × 20 m, PD and FDis significantly affected forest biomass productivity, while Shannon had only indirect effects. At the 40 × 40 m and 60 × 60 m scales, biodiversity and productivity were weakly correlated. The initial stand volume and biomass were the most important drivers of forest productivity. The local environmental conditions significantly influenced the stand volume, biomass, biodiversity, and productivity. The results highlight the scale dependency of the relationships between forest biodiversity and productivity. The positive role of biodiversity in facilitating forest productivity was confirmed at the smaller scales. Our findings emphasize the fundamental role of environmental conditions in determining forest ecosystem performances. The results of this study provide a better understanding

  5. Management impacts on forest floor and soil organic carbon in northern temperate forests of the US

    Science.gov (United States)

    Coeli M. Hoover

    2011-01-01

    The role of forests in the global carbon cycle has been the subject of a great deal of research recently, but the impact of management practices on forest soil dynamics at the stand level has received less attention. This study used six forest management experimental sites in five northern states of the US to investigate the effects of silvicultural treatments (light...

  6. Detection probabilities of woodpecker nests in mixed conifer forests in Oregon

    Science.gov (United States)

    Robin E. Russell; Victoria A. Saab; Jay J. Rotella; Jonathan G. Dudley

    2009-01-01

    Accurate estimates of Black-backed (Picoides arcticus) and Hairy Woodpecker (P. villosus) nests and nest survival rates in post-fire landscapes provide land managers with information on the relative importance of burned forests to nesting woodpeckers. We conducted multiple-observer surveys in burned and unburned mixed coniferous forests in Oregon to identify important...

  7. Examining conifer canopy structural complexity across forest ages and elevations with LiDAR data

    Science.gov (United States)

    Van R. Kane; Jonathan D. Bakker; Robert J. McGaughey; James A. Lutz; Rolf F. Gersonde; Jerry F. Franklin

    2010-01-01

    LiDAR measurements of canopy structure can be used to classify forest stands into structural stages to study spatial patterns of canopy structure, identify habitat, or plan management actions. A key assumption in this process is that differences in canopy structure based on forest age and elevation are consistent with predictions from models of stand development. Three...

  8. Accuracy of an IFSAR-derived digital terrain model under a conifer forest canopy.

    Science.gov (United States)

    Hans-Erik Andersen; Stephen E. Reutebuch; Robert J. McGaughey

    2005-01-01

    Accurate digital terrain models (DTMs) are necessary for a variety of forest resource management applications, including watershed management, timber harvest planning, and fire management. Traditional methods for acquiring topographic data typically rely on aerial photogrammetry, where measurement of the terrain surface below forest canopy is difficult and error prone...

  9. Emission of Nitrous Oxide in Temperate Forests with Different Stages of Nitrogen Saturation in Central Japan

    Science.gov (United States)

    Shaoyan, F.

    2015-12-01

    Long-term nitrogen deposition has caused a problem called nitrogen saturation in forest ecosystems globally. Aber et al. (1989) suggested that nitrogen saturation activate soil nitrification in forest systems, which is the main process of N2O production in aerobic condition. Thus, nitrogen saturation may affect significantly the N2O emission from forests, while the impact on flux has not been quantitatively evaluated yet. In the present study, 3-year monitoring of N2O emission was performed in an N-saturated forests (Tama Hill, Tokyo): the emission rate of N2O was measured monthly by a closed chamber method at 12 plots along a slope, and the net nitrification rate of surface soil (0-10 cm) was measured 4 times in situ. In addition, a comparative research was conducted in summer in eight temperate forests with different stages of nitrogen saturation in central Japan; the N2O flux, soil moisture, nitrogen availability and stream water NO3- concentration were measured at each site. In an N-saturated forests, the annual N2O emission was estimated to be 0.88 kg N ha-1year-1 , showing a typical seasonal variation . The seasonal patterns of N2O emission were significantly related to soil moisture and ambient temperature. We also found high spatial variation of N2O flux among 12 plots along the slope, which was generally higher at the bottom. Moreover, a positive correlation was found between the rate of N2O emission and the net nitrification rate with WFPS60% , probably due to the effect of denitrification. In comparison sites, the N2O emission rate ranged nearly 16-fold from 0.13-2.11 g N ha-1day-1 was linearly related to the stream water NO3- concentration ranged 10-fold from 0.14 to 1.4 mg N/L. Our results revealed N enrichment in forest obviously stimulate soil N2O emission. Keywords: Nitrous oxide, nitrogen saturation, nitrification, temperate forest

  10. Disturbance and decoupling of belowground carbon and nitrogen cycles in a northern temperate forest

    Science.gov (United States)

    Nave, L. E.; Nadelhoffer, K.; Le Moine, J.; Hardiman, B. S.; Sparks, J. P.; Strahm, B. D.; Munoz, A.; Gough, C. M.; Vogel, C. S.; Curtis, P.

    2011-12-01

    Belowground carbon (C) and nitrogen (N) cycles are tightly coupled in many northern temperate forests. However, disturbances that cause tree mortality can decouple linkages between belowground components of these biogeochemical cycles. We measured a suite of belowground processes following a treatment to accelerate the natural senescence of early-successional dominants in a northern temperate forest, hypothesizing that tree mortality would decrease belowground C allocation, increase belowground N availability and cycling rates, and trigger N leaching in this highly N-limited forest. In the Forest Accelerated Succession ExperimenT, we stem girdled >6700 aspen and birch trees (39% of basal area) on 40 ha of forestland at the University of Michigan Biological Station to test these and other hypotheses related to forest development and biogeochemistry. Here, we present the cascade of changes in belowground C and N cycling that occurred in the first two growing seasons following initiation of FASET in April 2008. Aspen and birch mortality decreased stand-level fine root nonstructural carbohydrate contents, accelerating fine root turnover and causing a net reduction in fine root biomass. These decreases in belowground C allocation and root functioning increased forest floor net NH4+ availability, which accelerated nitrification rates, increased net NO3- availability, and led to small NO3- leaching losses. These belowground perturbations were registered by the forest canopy through shifts in foliar 13C and 15N natural abundances, which indicated water stress among girdled aspens and faster, leakier cycling in a source N pool shared by foliage of all tree species. We interpret the results of this initial disturbance phase of the FASET study in the context of our conceptual model of N availability and ecosystem C storage over longer-term (successional) time scales. We predict that, following minor N leaching losses during disturbance, reorganization of belowground N cycling

  11. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America.

    Science.gov (United States)

    Stevens, Jens T; Safford, Hugh D; North, Malcolm P; Fried, Jeremy S; Gray, Andrew N; Brown, Peter M; Dolanc, Christopher R; Dobrowski, Solomon Z; Falk, Donald A; Farris, Calvin A; Franklin, Jerry F; Fulé, Peter Z; Hagmann, R Keala; Knapp, Eric E; Miller, Jay D; Smith, Douglas F; Swetnam, Thomas W; Taylor, Alan H

    Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the "stand age" variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical "mixed-severity" fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data.

  12. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

    Science.gov (United States)

    Stevens, Jens T.; Safford, Hugh D.; North, Malcolm P.; Fried, Jeremy S.; Gray, Andrew N.; Brown, Peter M.; Dolanc, Christopher R.; Dobrowski, Solomon Z.; Falk, Donald A.; Farris, Calvin A.; Franklin, Jerry F.; Fulé, Peter Z.; Hagmann, R. Keala; Knapp, Eric E.; Miller, Jay D.; Smith, Douglas F.; Swetnam, Thomas W.; Taylor, Alan H.

    2016-01-01

    Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the “stand age” variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical “mixed-severity” fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data. PMID:27196621

  13. Ectomycorrhizal fungus communities of Quercus liaotungensis Koidz of different ages in a northern China temperate forest.

    Science.gov (United States)

    Wang, Qin; He, Xin Hua; Guo, Liang-Dong

    2012-08-01

    Ectomycorrhizal (ECM) fungal communities of Quercus liaotungensis of different ages (seedlings, young trees and mature trees) in the growing seasons (June and September) between 2007 and 2009 were studied in a temperate forest of northern China. A total of 66 ECM fungal taxa were identified based on ECM morphotyping, PCR-RFLP, and DNA sequence data. Of these fungal taxa, 51 were Basidiomycetes (77.3%) and 15 were Ascomycetes (22.7%). Cenococcum geophilum was the dominant species. Thelephoraceae (16 taxa), Sebacinaceae (12 taxa) and Russulaceae (seven taxa) were the most species-rich and abundant ECM fungi, accounting for 19.5%, 17.6% and 8.3% of the total ECM root tips, respectively. Results of multiple response permutation procedure (MRPP) analysis indicated that there were marginally significant effects of tree ages (A = 0.01801, P = 0.054) and growing seasons (A = 0.01908, P = 0.064) on the ECM fungal species composition of Q. liaotungensis in a temperate forest.

  14. Threats to large brown algal forests in temperate seas: the overlooked role of native herbivorous fish.

    Science.gov (United States)

    Gianni, Fabrizio; Bartolini, Fabrizio; Pey, Alexis; Laurent, Mathieu; Martins, Gustavo M; Airoldi, Laura; Mangialajo, Luisa

    2017-07-20

    Canopy-forming algae are declining globally due to multiple disturbances. This decline has recently been on the increase due to the spread of some tropical herbivorous fishes. This new phenomenon has drawn attention to the effects of fish herbivory in temperate areas, which have been assumed to be negligible compared to that of invertebrates, such as sea urchins. In this study, the impact of a Mediterranean native herbivorous fish (Sarpa salpa, salema) was assessed on the canopy-forming seaweed Cystoseira amentacea var. stricta. Cystoseira amentacea forms belts in the infralittoral fringe of wave-exposed shores, which has so far been considered a refuge from fish herbivory. To test the effects of salema feeding on natural C. amentacea belts, an innovative herbivore deterrent device was conceived. Salema had a significant effect on C. amentacea by decreasing algal size, biomass and fertility, by up to 97%. The results suggest that the contribution of salema feeding to the loss of Cystoseira forests in the Mediterranean may have been overlooked. In addition, the analysis of temporal and spatial patterns of salema landings in the Mediterranean Sea suggests that salema abundance may have increased recently. Thus, along with invertebrate herbivory and anthropogenic stressors, fish herbivory may also represent a potential threat to algal forests in temperate areas.

  15. Seasonal variation of CO{sub 2} flux between air and temperate forest

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Susumo; Murayama, Shohei; Kondo, Hiroaki [National Inst. for Resources and Environment, Ibaraki (Japan)

    1995-12-31

    Carbon dioxide, which is a very important greenhouse gas, contributes approximately 55 % to the problem of global warming. The knowledge to the sources and sinks of carbon on a global basis is very poor. IPCC (1994) suggested that unknown 1.5-2.0 GtC/year may be sunk in terrestrial ecosystem, in particular, in the Northern Hemisphere. As can be seen from a recent estimation of the carbon fluxes in the terrestrial biosphere, there is a high degree of uncertainty in the magnitude. The clear evidence for it has not been shown yet by IPCC (1994). However, based on the gradient of CO{sub 2}, as a function of latitude, main CO{sub 2} sink can be thought to be in the terrestrial biosphere, in the middle to high latitude of the Northern Hemisphere. As can be seen from a recent estimation of the carbon fluxes in the terrestrial biosphere, there is a high degree of uncertainty in the magnitude. From this view, more investigation of the role of the temperate forest on the CO{sub 2} balance is inevitable. In this presentation, the seasonal variation of CO{sub 2} flux between air and biosphere in temperate deciduous forest in Japan is intended to be elucidated. (author)

  16. Synthesis on the carbon budget and cycling in a Danish, temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; Larsen, Klaus Steenberg; van der Linden, Leon

    2013-01-01

    A synthesis of five years (2006–2010) of data on carbon cycling in a temperate deciduous forest, Sorø (Zealand, Denmark) was performed by combining all available data from eddy covariance, chamber, suction cups, and biometric measurements. The net ecosystem exchange of CO2 (NEE), soil respiration...... within the ecosystem. The results showed that this temperate deciduous forest was a moderate carbon sink (258±41gCm−2 yr−1) with both high rates of gross primary production (GPP, 1881±95gCm−2 yr−1) and ecosystem respiration (Re, 1624±197gCm−2 yr−1). Approximately 62% of the gross assimilated carbon...... was considered unchanged over the period of observation, given the high degree of uncertainty associated with the small loss detected (33±85gCm−2 yr−1). The ECB component data were generally consistent, except for one of the derived fluxes, the aboveground autotrophic respiration, which appeared to be higher...

  17. Role of burning season on initial understory vegetation response to prescribed fire in a mixed conifer forest

    Science.gov (United States)

    Knapp, E.E.; Schwilk, D.W.; Kane, J.M.; Keeley, J.E.

    2007-01-01

    Although the majority of fires in the western United States historically occurred during the late summer or early fall when fuels were dry and plants were dormant or nearly so, early-season prescribed burns are often ignited when fuels are still moist and plants are actively growing. The purpose of this study was to determine if burn season influences postfire vegetation recovery. Replicated early-season burn, late-season burn, and unburned control units were established in a mixed conifer forest, and understory vegetation was evaluated before and after treatment. Vegetation generally recovered rapidly after prescribed burning. However, late-season burns resulted in a temporary but significant drop in cover and a decline in species richness at the 1 m 2 scale in the following year. For two of the several taxa that were negatively affected by burning, the reduction in frequency was greater after late-season than early-season burns. Early-season burns may have moderated the effect of fire by consuming less fuel and lessening the amount of soil heating. Our results suggest that, when burned under high fuel loading conditions, many plant species respond more strongly to differences in fire intensity and severity than to timing of the burn relative to stage of plant growth. ?? 2007 NRC.

  18. Long and Short-Term Effects of Fire on Soil Charcoal of a Conifer Forest in Southwest Oregon

    Directory of Open Access Journals (Sweden)

    Brett Morrissette

    2012-06-01

    Full Text Available In 2002, the Biscuit Wildfire burned a portion of the previously established, replicated conifer unthinned and thinned experimental units of the Siskiyou Long-Term Ecosystem Productivity (LTEP experiment, southwest Oregon. Charcoal C in pre and post-fire O horizon and mineral soil was quantified by physical separation and a peroxide-acid digestion method. The abrupt, short-term fire event caused O horizon charcoal C to increase by a factor of ten to >200 kg C ha−1. The thinned wildfire treatment produced less charcoal C than unthinned wildfire and thinned prescribed fire treatments. The charcoal formation rate was 1 to 8% of woody fuels consumed, and this percentage was negatively related to woody fuels consumed, resulting in less charcoal formation with greater fire severity. Charcoal C averaged 2000 kg ha−1 in 0–3 cm mineral soil and may have decreased as a result of fire, coincident with convective or erosive loss of mineral soil. Charcoal C in 3–15 cm mineral soil was stable at 5500 kg C ha−1. Long-term soil C sequestration in the Siskiyou LTEP soils is greatly influenced by the contribution of charcoal C, which makes up 20% of mineral soil organic C. This research reiterates the importance of fire to soil C in a southwestern Oregon coniferous forest ecosystem.

  19. Edge effects on moisture reduce wood decomposition rate in a temperate forest.

    Science.gov (United States)

    Crockatt, Martha E; Bebber, Daniel P

    2015-02-01

    Forests around the world are increasingly fragmented, and edge effects on forest microclimates have the potential to affect ecosystem functions such as carbon and nutrient cycling. Edges tend to be drier and warmer due to the effects of insolation, wind, and evapotranspiration and these gradients can penetrate hundreds of metres into the forest. Litter decomposition is a key component of the carbon cycle, which is largely controlled by saprotrophic fungi that respond to variation in temperature and moisture. However, the impact of forest fragmentation on litter decay is poorly understood. Here, we investigate edge effects on the decay of wood in a temperate forest using an experimental approach, whereby mass loss in wood blocks placed along 100 m transects from the forest edge to core was monitored over 2 years. Decomposition rate increased with distance from the edge, and was correlated with increasing humidity and moisture content of the decaying wood, such that the decay constant at 100 m was nearly twice that at the edge. Mean air temperature decreased slightly with distance from the edge. The variation in decay constant due to edge effects was larger than that expected from any reasonable estimates of climatic variation, based on a published regional model. We modelled the influence of edge effects on the decay constant at the landscape scale using functions for forest area within different distances from edge across the UK. We found that taking edge effects into account would decrease the decay rate by nearly one quarter, compared with estimates that assumed no edge effect. © 2014 John Wiley & Sons Ltd.

  20. Patterns of drought tolerance in major European temperate forest trees: climatic drivers and levels of variability.

    Science.gov (United States)

    Zang, Christian; Hartl-Meier, Claudia; Dittmar, Christoph; Rothe, Andreas; Menzel, Annette

    2014-12-01

    The future performance of native tree species under climate change conditions is frequently discussed, since increasingly severe and more frequent drought events are expected to become a major risk for forest ecosystems. To improve our understanding of the drought tolerance of the three common European temperate forest tree species Norway spruce, silver fir and common beech, we tested the influence of climate and tree-specific traits on the inter and intrasite variability in drought responses of these species. Basal area increment data from a large tree-ring network in Southern Germany and Alpine Austria along a climatic cline from warm-dry to cool-wet conditions were used to calculate indices of tolerance to drought events and their variability at the level of individual trees and populations. General patterns of tolerance indicated a high vulnerability of Norway spruce in comparison to fir and beech and a strong influence of bioclimatic conditions on drought response for all species. On the level of individual trees, low-growth rates prior to drought events, high competitive status and low age favored resilience in growth response to drought. Consequently, drought events led to heterogeneous and variable response patterns in forests stands. These findings may support the idea of deliberately using spontaneous selection and adaption effects as a passive strategy of forest management under climate change conditions, especially a strong directional selection for more tolerant individuals when frequency and intensity of summer droughts will increase in the course of global climate change. © 2014 John Wiley & Sons Ltd.

  1. Net carbon uptake has increased through warming-induced changes in temperate forest phenology

    Energy Technology Data Exchange (ETDEWEB)

    Keenan, Trevor [Harvard University; Gray, Josh [Boston University; Friedl, Mark [Boston University; Toomey, Michael [Harvard University; Bohrer, Gil [Ohio State University; Hollinger, David [USDA Forest Service, Northern Research Station; Munger, J. William [Harvard University; OKeefe, John [Harvard Forest (Harvard University), Massachusetts; Hans, Schmid [Karlsruhe Institute of Technology, Karlsruhe, Germany; Wing, Ian [Boston University; Yang, Bai [ORNL; Richardson, Andrew D. [Harvard University

    2014-01-01

    The timing of phenological events exerts a strong control over ecosystem function and leads to multiple feedbacks to the climate system1. Phenology is inherently sensitive to temperature (though the exact sensitivity is disputed2) and recent warming is reported to have led to earlier spring, later autumn3,4 and increased vegetation activity5,6. Such greening could be expected to enhance ecosystem carbon uptake7,8, though reports also suggest decreased uptake for boreal forests4,9. Here we assess changes in phenology of temperate forests over the eastern US during the past two decades, and quantify the resulting changes in forest carbon storage. We combine long-term ground observations of phenology, satellite indices, and ecosystem-scale carbon dioxide flux measurements, along with 18 terrestrial biosphere models. We observe a strong trend of earlier spring and later autumn. In contrast to previous suggestions4,9 we show that carbon uptake through photosynthesis increased considerably more than carbon release through respiration for both an earlier spring and later autumn. The terrestrial biosphere models tested misrepresent the temperature sensitivity of phenology, and thus the effect on carbon uptake. Our analysis of the temperature-phenology-carbon coupling suggests a current and possible future enhancement of forest carbon uptake due to changes in phenology. This constitutes a negative feedback to climate change, and is serving to slow the rate of warming.

  2. Processes governing yearly variations in carbon sequestration at a temperate deciduous forest

    Science.gov (United States)

    Barr, J. G.; Fuentes, J. D.; Staebler, R.; Lee, X.

    2001-12-01

    Since 1995, processes governing the net ecosystem exchange (NEE) of carbon dioxide have been continuously investigated at the CFB Borden temperate mixed deciduous forest in Ontario, Canada. On a yearly basis, the rates of NEE for this forest range from 0.3 to 2.5 t C ha-1. For the 1996 to 1999 period, the forest sequestered the most carbon and had the greatest seasonal carbon dioxide flux in 1997. This seasonal flux is defined as the average daily rate of NEE over the course of the growing period and is the single most important factor governing yearly NEE. Such factors as soil temperature, timing of soil thawing, and respiratory processes exert only minor influences on the yearly variability in NEE. In this presentation, we will provide evidence to support the hypothesis that maximum Rubisco capacity per unit foliage element is one key control on the NEE variability. Additionally, changes in diffuse photosysnthetically active irradiance contribute to the variability observed in NEE. We will present results from both data analyses and outputs from a biospheric modeling system which was employed to investigate seasonal rates of NEE for the Borden forest.

  3. Seasonal carbon fluxes for an old-growth temperate forest inferred from carbonyl sulphide

    Science.gov (United States)

    Rastogi, Bharat; Jiang, Yueyang; Berkelhammer, Maxwell; Wharton, Sonia; Noone, David; Still, Christopher

    2017-04-01

    Characterizing and quantifying the processes that control terrestrial ecosystem exchanges of carbon and water are critical for understanding how forested ecosystems respond to a changing climate. A small but increasing number of studies has identified carbonyl sulfide (OCS) as a potential tracer of canopy photosynthesis and stomatal function. Here we present seasonal fluxes of OCS from a 60m tall old-growth temperate forest. An off-axis integrated cavity output spectroscopy analyzer (Los Gatos Research Inc.) was deployed at the Wind River Experimental Forest in Washington (45.8205°N, 121.9519°W) in 2014 and 2015. GPP (Gross Primary Production) is inferred from OCS fluxes and compared with estimates derived from measurements of NEE (Net Ecosystem Exchange) from eddy flux data as well as GPP predictions using a process based model. Our findings seek to resolve scientific questions regarding ecosystem carbon exchange from tall old growth forests, which have a complicated vertical leaf area structure, high above ground biomass and amount and aerial cover of epiphytic vegetation. Estimates of canopy conductance calculated using tower flux data are also combined with measurements of stable isotopologues of CO2 to infer emergent ecosystem properties such as canopy ci/ca and water use efficiency.

  4. Longhorned beetle (Coleoptera: Cerambycidae diversity in a fragmented temperate forest landscape [v2; ref status: indexed, http://f1000r.es/yz

    Directory of Open Access Journals (Sweden)

    Daniel M Pavuk

    2013-03-01

    Full Text Available Longhorned beetles (Coleoptera: Cerambycidae are an important component of temperate forest ecosystems.  We trapped longhorned beetles in forests in northwest Ohio during 2008 to test the hypothesis that larger forests have greater species diversity than smaller forests.  Large forests had a significantly greater cerambycid species richness than small forests (t = 3.16. P = 0.02, and there was a significant relationship between forest size and cerambycid species richness.

  5. Forest stand structure and pattern of old-growth western hemlock/Douglas-fir and mixed-conifer forests

    Science.gov (United States)

    Malcolm North; Jiquan Chen; Brian Oakley; Bo Song; Mark Rudnicki; Andrew Gray; Jim Innes

    2004-01-01

    With fire suppression, many western forests are expected to have fewer gaps and higher stem density of shade-tolerant species as light competition becomes a more significant influence on stand pattern and composition. We compared species composition, structure, spatial pattern, and environmental factors such as light and soil moisture between two old-growth forests:...

  6. A comparison of forest canopy models derived from LIDAR and INSAR data in a Pacific Northwest conifer forest.

    Science.gov (United States)

    Hans-Erik Andersen; Robert J. McGaughey; Ward W. Carson; Stephen E. Reutebuch; Bryan Mercer; Jeremy. Allan

    2004-01-01

    Active remote sensing technologies, including interferometric radar (InSAR) and airborne laser scanning (LIDAR) have the potential to provide accurate information relating to three-dimensional forest canopy structure over extensive areas of the landscape. In order to assess the capabilities of these alternative systems for characterizing the forest canopy dimensions,...

  7. δ15N constraints on long-term nitrogen balances in temperate forests

    Science.gov (United States)

    Perakis, S.S.; Sinkhorn, E.R.; Compton, J.E.

    2011-01-01

    Biogeochemical theory emphasizes nitrogen (N) limitation and the many factors that can restrict N accumulation in temperate forests, yet lacks a working model of conditions that can promote naturally high N accumulation. We used a dynamic simulation model of ecosystem N and δ15N to evaluate which combination of N input and loss pathways could produce a range of high ecosystem N contents characteristic of forests in the Oregon Coast Range. Total ecosystem N at nine study sites ranged from 8,788 to 22,667 kg ha−1 and carbon (C) ranged from 188 to 460 Mg ha−1, with highest values near the coast. Ecosystem δ15N displayed a curvilinear relationship with ecosystem N content, and largely reflected mineral soil, which accounted for 96–98% of total ecosystem N. Model simulations of ecosystem N balances parameterized with field rates of N leaching required long-term average N inputs that exceed atmospheric deposition and asymbiotic and epiphytic N2-fixation, and that were consistent with cycles of post-fire N2-fixation by early-successional red alder. Soil water δ15NO3 − patterns suggested a shift in relative N losses from denitrification to nitrate leaching as N accumulated, and simulations identified nitrate leaching as the primary N loss pathway that constrains maximum N accumulation. Whereas current theory emphasizes constraints on biological N2-fixation and disturbance-mediated N losses as factors that limit N accumulation in temperate forests, our results suggest that wildfire can foster substantial long-term N accumulation in ecosystems that are colonized by symbiotic N2-fixing vegetation.

  8. Sapling growth rates reveal conspecific negative density dependence in a temperate forest.

    Science.gov (United States)

    Ramage, Benjamin S; Johnson, Daniel J; Gonzalez-Akre, Erika; McShea, William J; Anderson-Teixeira, Kristina J; Bourg, Norman A; Clay, Keith

    2017-10-01

    Local tree species diversity is maintained in part by conspecific negative density dependence (CNDD). This pervasive mechanism occurs in a variety of forms and ecosystems, but research to date has been heavily skewed toward tree seedling survival in tropical forests. To evaluate CNDD more broadly, we investigated how sapling growth rates were affected by conspecific adult neighbors in a fully mapped 25.6 ha temperate deciduous forest. We examined growth rates as a function of the local adult tree neighborhood (via spatial autoregressive modeling) and compared the spatial positioning of faster-growing and slower-growing saplings with respect to adult conspecific and heterospecific trees (via bivariate point pattern analysis). In addition, to determine whether CNDD-driven variation in growth rates leaves a corresponding spatial signal, we extended our point pattern analysis to a static, growth-independent comparison of saplings and the next larger size class. We found that negative conspecific effects on sapling growth were most prevalent. Five of the nine species that were sufficiently abundant for analysis exhibited CNDD, while only one species showed evidence of a positive conspecific effect, and one or two species, depending on the analysis, displayed heterospecific effects. There was general agreement between the autoregressive models and the point pattern analyses based on sapling growth rates, but point pattern analyses based on single-point-in-time size classes yielded results that differed markedly from the other two approaches. Our work adds to the growing body of evidence that CNDD is an important force in temperate forests, and demonstrates that this process extends to sapling growth rates. Further, our findings indicate that point pattern analyses based solely on size classes may fail to detect the process of interest (e.g., neighborhood-driven variation in growth rates), in part due to the confounding of tree size and age.

  9. The selection of small forest hollows for pollen analysis in boreal and temperate forest regions

    DEFF Research Database (Denmark)

    Overballe-Petersen, Mette V; Bradshaw, Richard H.W.

    2011-01-01

    Small forest hollows represent a specialised site type for pollen analysis, since they mainly record the vegetation within an approximate radius of 20-100 m from the hollow. We discuss how to choose the most appropriate small forest hollow for pollen analysis. Hollow size, site topography, location...

  10. Considerations for restoring temperate forests of tomorrow: Forest restoration, assisted migration, and bioengineering

    Science.gov (United States)

    Kas Dumroese; Mary I. Williams; John A. Stanturf; Brad St. Clair

    2015-01-01

    Tomorrow’s forests face extreme pressures from contemporary climate change, invasive pests, and anthropogenic demands for other land uses. These pressures, collectively, demand land managers to reassess current and potential forest management practices. We discuss three considerations, functional restoration, assisted migration, and bioengineering, which are currently...

  11. Estimating Carbon Storage of a Temperate North American Forest with Terrestrial Laser Scanning (TLS)

    Science.gov (United States)

    Stovall, A. E.; Shugart, H. H.

    2013-12-01

    Secondary forests in North America act as one of the largest active carbon sinks in the world, yet current estimates of forest biomass are widely varied when based on allometric equations alone. Remote sensing data such as LIDAR offers an excellent method of quantifying biomass, but information on structural heterogeneity is often lost, even with postings of approximately 0.5 meters. In order to inform estimates of biomass and carbon storage the use of a high-precision Terrestrial Laser Scanner (TLS) can be employed and three-dimensional structure of the forest can be resolved with sub-centimeter accuracy, improving current allometric equations. This technology is utilized on 16 15-meter radius plots within the temperate forest of the Smithsonian Conservation Biology Institute outside of Front Royal, VA with a Faro Focus 3D. A stem map of this forest has recently been created, allowing a direct comparison between manual measurement methods and TLS. Standard measurements such as DBH, tree height, and basal area can then quickly be calculated within the three-dimensional point cloud. A DEM at the plot scale is developed with the point cloud data and the structure of the forest can be resolved. Volumetric calculations can be used to determine biomass at the plot level, a fine-scale variable that is otherwise not obtainable without destruction of the sample. The calculation of biomass will inform current estimates of carbon storage that have been made with course 30 m resolution data (i.e. Landsat). Canopy and understory structure can be analyzed with these methods, helping inform current knowledge of habitat suitability and complexity.

  12. Ozone deposition in relation to canopy physiology in a mixed conifer forest in Denmark

    DEFF Research Database (Denmark)

    Ro-Poulsen, H.; Mikkelsen, Teis Nørgaard; Hovmand, M.F.

    1998-01-01

    In this study CO(2) and H(2)O flux measurements made above a spruce forest was compared with the ozone flux to the canopy during growing season 1995. The fluxes were determined by micro meteorological gradient methods using a 36-m tall meteorological mast. The trees were about 12 m high and air...... sampling was done from 36 and 18 m. The preliminary results suggest that there is only little correlation between ozone concentration in 36 m and the ozone flux to the forest, but the diurnal pattern of ozone uptake seems to be significantly influenced by stomatal conductance. The cumulative total ozone...

  13. Recovery of ectomycorrhiza after ‘nitrogen saturation’ of a conifer forest

    DEFF Research Database (Denmark)

    Högberg, Peter; Johannisson, Christian; Yarwood, Stephanie

    2011-01-01

    Trees reduce their carbon (C) allocation to roots and mycorrhizal fungi in response to high nitrogen (N) additions, which should reduce the N retention capacity of forests. The time needed for recovery of mycorrhizas after termination of N loading remains unknown. Here, we report the long......-term impact of N loading and the recovery of ectomycorrhiza after high N loading on a Pinus sylvestris forest. We analysed the N% and abundance of the stable isotope 15N in tree needles and soil, soil microbial fatty acid biomarkers and fungal DNA. Needles in N-loaded plots became enriched in 15N, reflecting...

  14. Ponderosa pine, mixed conifer, and spruce-fir forests [Chapter 2

    Science.gov (United States)

    Michael A. Battaglia; Wayne D. Shepperd

    2007-01-01

    Before European settlement of the interior west of the United States, coniferous forests of this region were influenced by many disturbance regimes, primarily fires, insects, diseases, and herbivory, which maintained a diversity of successional stages and vegetative types across landscapes. Activities after settlement, such as fire suppression, grazing, and logging...

  15. Evaluating avian-habitat relationships models in mixed-conifer forests of the Sierra Nevada

    Science.gov (United States)

    Kathryn L. Purcell; Sallie J. Hejl; Terry A. Larson

    1992-01-01

    Using data from two studies in the southern and central Sierra Nevada, we compared the presence and abundance of bird species breeding in mixedconifer forests during 1978-79 and 1983-85 to predictions &om the California Wildlife Habitat Relationships (WHR) System. Twelve percent of the species observed in either study were not predicted by the WHR database to occur...

  16. Modification of mixed-conifer forests by ruminant herbivores in the Blue Mountains ecological province.

    Science.gov (United States)

    Robert A. Riggs; Arthur R. Tiedemann; John G. Cook; et al.

    2000-01-01

    Secondary plant succession and the accumulation of biomass and nutrients were documented at seven ruminant exclosures in Abies and Pseudotsuga forests variously disturbed by logging, burning, and grass seeding. Long-term (25 or more years) foraging by Rocky Mountain mule deer (Odocoileus hemionus) and Rocky Mountain elk (Cervus elaphus...

  17. Photo series for quantifying forest fuels in Mexico: montane subtropical forests of the Sierra Madre del Sur and temperate forests and montane shrubland of the northern Sierra Madre Oriental

    Science.gov (United States)

    Jorge E. Morfin-Rios; Ernesto Alvarado-Celestino; Enrique J. Jardel-Pelaez; Robert E. Vihnanek; David K. Wright; Jose M. Michel-Fuentes; Clinton S. Wright; Roger D. Ottmar; David V. Sandberg; Andres Najera-Diaz

    2008-01-01

    Single wide-angle and stereo photographs display a range of forest ecosystems conditions and fuel loadings in montane subtropical forests of the Sierra Madre del Sur and temperate forests and montane shrubland of the northern Sierra Madre Oriental of Mexico. Each group of photographs includes inventory information summarizing overstory vegetation composition and...

  18. Impacts of cloud immersion on microclimate, photosynthesis and water relations of fraser fir in a temperate mountain cloud forest

    Science.gov (United States)

    Keith Reinhardt; William K. Smith

    2010-01-01

    The red spruce-Fraser fir ecosystem (Picea rubens Sarg.-Abies fraseri [Pursh] Poir.) of the southern Appalachian mountains is a temperate zone cloud forest immersed in clouds for 30 to 40 percent of a typical summer day, and experiencing immersion on about 65 percent of all days annually. We compared the microclimate,...

  19. A tale of two springs: using recent climate anomalies to characterize the sensitivity of temperate forest phenology to climate change

    Science.gov (United States)

    Mark A Friedl; Josh M Gray; Eli K Melaas; Andrew D Richardson; Koen Hufkens; Trevor F Keenan; Amey Bailey; John. O' Keefe

    2014-01-01

    By the end of this century, mean annual temperatures in the Northeastern United States are expected to warm by 3-5 °C, which will have significant impacts on the structure and function of temperate forests in this region. To improve understanding of these impacts, we exploited two recent climate anomalies to explore how the springtime phenology of Northeastern...

  20. Wood ant nests as hot spots of carbon dioxide production and cold spots of methane oxidation in temperate forests

    Czech Academy of Sciences Publication Activity Database

    Jílková, Veronika; Picek, T.; Cajthaml, Tomáš; Frouz, Jan

    2016-01-01

    Roč. 18, April (2016), EGU2016-4634 ISSN 1607-7962. [European Geosciences Union General Assembly 2016. 17.04.2016-22.04.2016, Vienna] Institutional support: RVO:60077344 ; RVO:61388971 Keywords : wood ant nests * hot spots of carbon dioxide production * cold spots of methane oxidation * temperate forests Subject RIV: DF - Soil Science

  1. Decay of aspen (Populus tremuloides Michx.) wood in moist and dry boreal, temperate, and tropical forest fragments

    Science.gov (United States)

    Grizelle Gonzalez; William Gould; Andrew T. Hudak; Teresa Nettleton Hollingsworth

    2008-01-01

    In this study, we set up a wood decomposition experiment to i) quantify the percent of mass remaining, decay constant and performance strength of aspen stakes (Populus tremuloides) in dry and moist boreal (Alaska and Minnesota, USA), temperate (Washington and Idaho, USA), and tropical (Puerto Rico) forest types, and ii) determine the effects of...

  2. Substrate availability drives spatial patterns in richness of ammonia-oxidizing bacteria and archaea in temperate forest soils

    Science.gov (United States)

    J.S. Norman; J.E. Barrett

    2016-01-01

    We sought to investigate the drivers of richness of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in temperate forest soils. We sampled soils across four experimental watersheds in the Coweeta Hydrologic Laboratory, North Carolina USA. These watersheds are geographically close, but vary in soil chemistry due to differences in land use history. While we...

  3. Macro-particle charcoal C content following prescribed burning in a mixed-conifer forest, Sierra Nevada, California.

    Science.gov (United States)

    Wiechmann, Morgan L; Hurteau, Matthew D; Kaye, Jason P; Miesel, Jessica R

    2015-01-01

    Fire suppression and changing climate have resulted in increased large wildfire frequency and severity in the western United States, causing carbon cycle impacts. Forest thinning and prescribed burning reduce high-severity fire risk, but require removal of biomass and emissions of carbon from burning. During each fire a fraction of the burning vegetation and soil organic matter is converted into charcoal, a relatively stable carbon form. We sought to quantify the effects of pre-fire fuel load and type on charcoal carbon produced by biomass combusted in a prescribed burn under different thinning treatments and to identify more easily measured predictors of charcoal carbon mass in a historically frequent-fire mixed-conifer forest. We hypothesized that charcoal carbon produced from coarse woody debris (CWD) during prescribed burning would be greater than that produced from fine woody debris (FWD). We visually quantified post-treatment charcoal carbon content in the O-horizon and the A-horizon beneath CWD (> 30 cm diameter) and up to 60 cm from CWD that was present prior to treatment. We found no difference in the size of charcoal carbon pools from CWD (treatment means ranged from 0.3-2.0 g m-2 of A-horizon and 0.0-1.7 g m-2 of O-horizon charcoal) and FWD (treatment means ranged from 0.2-1.7 g m-2 of A-horizon and 0.0-1.5 g m-2 of O-horizon charcoal). We also compared treatments and found that the burn-only, understory-thin and burn, and overstory-thin and burn treatments had significantly more charcoal carbon than the control. Charcoal carbon represented 0.29% of total ecosystem carbon. We found that char mass on CWD was an important predictor of charcoal carbon mass, but only explained 18-35% of the variation. Our results help improve our understanding of the effects forest restoration treatments have on ecosystem carbon by providing additional information about charcoal carbon content.

  4. Accounting for Biomass Carbon Stock Change Due to Wildfire in Temperate Forest Landscapes in Australia

    Science.gov (United States)

    Keith, Heather; Lindenmayer, David B.; Mackey, Brendan G.; Blair, David; Carter, Lauren; McBurney, Lachlan; Okada, Sachiko; Konishi-Nagano, Tomoko

    2014-01-01

    Carbon stock change due to forest management and disturbance must be accounted for in UNFCCC national inventory reports and for signatories to the Kyoto Protocol. Impacts of disturbance on greenhouse gas (GHG) inventories are important for many countries with large forest estates prone to wildfires. Our objective was to measure changes in carbon stocks due to short-term combustion and to simulate longer-term carbon stock dynamics resulting from redistribution among biomass components following wildfire. We studied the impacts of a wildfire in 2009 that burnt temperate forest of tall, wet eucalypts in south-eastern Australia. Biomass combusted ranged from 40 to 58 tC ha−1, which represented 6–7% and 9–14% in low- and high-severity fire, respectively, of the pre-fire total biomass carbon stock. Pre-fire total stock ranged from 400 to 1040 tC ha−1 depending on forest age and disturbance history. An estimated 3.9 TgC was emitted from the 2009 fire within the forest region, representing 8.5% of total biomass carbon stock across the landscape. Carbon losses from combustion were large over hours to days during the wildfire, but from an ecosystem dynamics perspective, the proportion of total carbon stock combusted was relatively small. Furthermore, more than half the stock losses from combustion were derived from biomass components with short lifetimes. Most biomass remained on-site, although redistributed from living to dead components. Decomposition of these components and new regeneration constituted the greatest changes in carbon stocks over ensuing decades. A critical issue for carbon accounting policy arises because the timeframes of ecological processes of carbon stock change are longer than the periods for reporting GHG inventories for national emissions reductions targets. Carbon accounts should be comprehensive of all stock changes, but reporting against targets should be based on human-induced changes in carbon stocks to incentivise mitigation activities

  5. Accounting for biomass carbon stock change due to wildfire in temperate forest landscapes in Australia.

    Science.gov (United States)

    Keith, Heather; Lindenmayer, David B; Mackey, Brendan G; Blair, David; Carter, Lauren; McBurney, Lachlan; Okada, Sachiko; Konishi-Nagano, Tomoko

    2014-01-01

    Carbon stock change due to forest management and disturbance must be accounted for in UNFCCC national inventory reports and for signatories to the Kyoto Protocol. Impacts of disturbance on greenhouse gas (GHG) inventories are important for many countries with large forest estates prone to wildfires. Our objective was to measure changes in carbon stocks due to short-term combustion and to simulate longer-term carbon stock dynamics resulting from redistribution among biomass components following wildfire. We studied the impacts of a wildfire in 2009 that burnt temperate forest of tall, wet eucalypts in south-eastern Australia. Biomass combusted ranged from 40 to 58 tC ha(-1), which represented 6-7% and 9-14% in low- and high-severity fire, respectively, of the pre-fire total biomass carbon stock. Pre-fire total stock ranged from 400 to 1040 tC ha(-1) depending on forest age and disturbance history. An estimated 3.9 TgC was emitted from the 2009 fire within the forest region, representing 8.5% of total biomass carbon stock across the landscape. Carbon losses from combustion were large over hours to days during the wildfire, but from an ecosystem dynamics perspective, the proportion of total carbon stock combusted was relatively small. Furthermore, more than half the stock losses from combustion were derived from biomass components with short lifetimes. Most biomass remained on-site, although redistributed from living to dead components. Decomposition of these components and new regeneration constituted the greatest changes in carbon stocks over ensuing decades. A critical issue for carbon accounting policy arises because the timeframes of ecological processes of carbon stock change are longer than the periods for reporting GHG inventories for national emissions reductions targets. Carbon accounts should be comprehensive of all stock changes, but reporting against targets should be based on human-induced changes in carbon stocks to incentivise mitigation activities.

  6. Bacteria associated with decomposing dead wood in a natural temperate forest.

    Science.gov (United States)

    Tláskal, Vojtech; Zrustová, Petra; Vrška, Tomáš; Baldrian, Petr

    2017-12-01

    Dead wood represents an important pool of organic matter in forests and is one of the sources of soil formation. It has been shown to harbour diverse communities of bacteria, but their roles in this habitat are still poorly understood. Here, we describe the bacterial communities in the dead wood of Abies alba, Picea abies and Fagus sylvatica in a temperate natural forest in Central Europe. An analysis of environmental factors showed that decomposing time along with pH and water content was the strongest drivers of community composition. Bacterial biomass positively correlated with N content and increased with decomposition along with the concurrent decrease in the fungal/bacterial biomass ratio. Rhizobiales and Acidobacteriales were abundant bacterial orders throughout the whole decay process, but many bacterial taxa were specific either for young (<15 years) or old dead wood. During early decomposition, bacterial genera able to fix N2 and to use simple C1 compounds (e.g. Yersinia and Methylomonas) were frequent, while wood in advanced decay was rich in taxa typical of forest soils (e.g. Bradyrhizobium and Rhodoplanes). Although the bacterial contribution to dead wood turnover remains unclear, the community composition appears to reflect the changing conditions of the substrate and suggests broad metabolic capacities of its members. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  7. Temperate pine barrens and tropical rain forests are both rich in undescribed fungi.

    Science.gov (United States)

    Luo, Jing; Walsh, Emily; Naik, Abhishek; Zhuang, Wenying; Zhang, Keqin; Cai, Lei; Zhang, Ning

    2014-01-01

    Most of fungal biodiversity on Earth remains unknown especially in the unexplored habitats. In this study, we compared fungi associated with grass (Poaceae) roots from two ecosystems: the temperate pine barrens in New Jersey, USA and tropical rain forests in Yunnan, China, using the same sampling, isolation and species identification methods. A total of 426 fungal isolates were obtained from 1600 root segments from 80 grass samples. Based on the internal transcribed spacer (ITS) sequences and morphological characteristics, a total of 85 fungal species (OTUs) belonging in 45 genera, 23 families, 16 orders, and 6 classes were identified, among which the pine barrens had 38 and Yunnan had 56 species, with only 9 species in common. The finding that grass roots in the tropical forests harbor higher fungal species diversity supports that tropical forests are fungal biodiversity hotspots. Sordariomycetes was dominant in both places but more Leotiomycetes were found in the pine barrens than Yunnan, which may play a role in the acidic and oligotrophic pine barrens ecosystem. Equal number of undescribed fungal species were discovered from the two sampled ecosystems, although the tropical Yunnan had more known fungal species. Pine barrens is a unique, unexplored ecosystem. Our finding suggests that sampling plants in such unexplored habitats will uncover novel fungi and that grass roots in pine barrens are one of the major reservoirs of novel fungi with about 47% being undescribed species.

  8. Habitat selection of endemic birds in temperate forests in a biodiversity "Hotspot"

    Directory of Open Access Journals (Sweden)

    Roberto A. Moreno-García

    2014-08-01

    Full Text Available Aim of study: Our objective was to find habitat associations at a microhabitat level for two endemic birds in a Chilean temperate forest (biodiversity “hotspots”, in order to integrate biodiversity into forest planning.Area of study: Nahuelbuta Range, Chile.Material and methods: The two birds studied were Scelorchilus rubecula (Chucao Tapaculo and Scytalopus magellanicus (Magellanic Tapaculo, both belonging to the Rhinocryptidae family. Presence or absence of the two species was sampled in 57 census spots. Habitat was categorized according to presence/absence results. We assessed the influence of abiotic variables (altitude, exposure, slope and vegetation structure (percentage of understory cover, number of strata using a statistical cluster analysis.Main results: The two bird species selected the habitat. Most frequent presence was detected at a range of 600-1100 masl, but Magellanic Tapaculo was associated to more protected sites in terms of vegetation structure (50-75% for understory cover and 2-3 strata. Slope was the most relevant abiotic variable in habitat selection due to its linkage to vegetation traits in this area.Research highlights: Our results can help managers to integrate biodiversity (endemic fauna species into forest planning by preserving certain traits of the vegetation as part of a habitat (at a microhabitat level selected by the fauna species. That planning should be implemented with both an adequate wood harvesting cuts system and specific silvicultural treatments.Key words: Chile; Nahuelbuta; rhinocryptidae; cluster analysis; rorest planning; vegetation structure.

  9. Spring leaf phenology and the diurnal temperature range in a temperate maple forest.

    Science.gov (United States)

    Hanes, Jonathan M

    2014-03-01

    Spring leaf phenology in temperate climates is intricately related to numerous aspects of the lower atmosphere [e.g., surface energy balance, carbon flux, humidity, the diurnal temperature range (DTR)]. To further develop and improve the accuracy of ecosystem and climate models, additional investigations of the specific nature of the relationships between spring leaf phenology and various ecosystem and climate processes are required in different environments. This study used visual observations of maple leaf phenology, below-canopy light intensities, and micrometeorological data collected during the spring seasons of 2008, 2009, and 2010 to examine the potential influence of leaf phenology on a seasonal transition in the trend of the DTR. The timing of a reversal in the DTR trend occurred near the time when the leaves were unfolding and expanding. The results suggest that the spring decline in the DTR can be attributed primarily to the effect of canopy closure on daily maximum temperature. These findings improve our understanding of the relationship between leaf phenology and the diurnal temperature range in temperate maple forests during the spring. They also demonstrate the necessity of incorporating accurate phenological data into ecosystem and climate models and warrant a careful examination of the extent to which canopy phenology is currently incorporated into existing models.

  10. Measurements of the horizontal gradient of ammonia over a conifer forest in Denmark

    DEFF Research Database (Denmark)

    Hovmand, M.F.; Andersen, H.V.; Løfstrøm, P.

    1998-01-01

    Horizontal gradients of ammonia have been measured in order to determine the spatial variation of the concentration above a forest as a function of distance from ammonia emitting areas. Measurements were carried out in June 1994 during conditions with winds from north and west. Concentration leve...... concentration gradients, although calculated concentration levels may be higher than measured due to the use of yearly average emissions as input to the model calculations. (C) 1998 Elsevier Science Ltd. All rights reserved....... in the forest; in general the percentage decreases were lower during northerly winds (16%) than those obtained during westerly winds (67%). This is probably due to the larger extension of emitting areas towards north than towards the west. Model calculations are comparable with the measured ammonia...

  11. Increased drought impacts on temperate rainforests from southern South America: results of a process-based, dynamic forest model.

    Science.gov (United States)

    Gutiérrez, Alvaro G; Armesto, Juan J; Díaz, M Francisca; Huth, Andreas

    2014-01-01

    Increased droughts due to regional shifts in temperature and rainfall regimes are likely to affect forests in temperate regions in the coming decades. To assess their consequences for forest dynamics, we need predictive tools that couple hydrologic processes, soil moisture dynamics and plant productivity. Here, we developed and tested a dynamic forest model that predicts the hydrologic balance of North Patagonian rainforests on Chiloé Island, in temperate South America (42°S). The model incorporates the dynamic linkages between changing rainfall regimes, soil moisture and individual tree growth. Declining rainfall, as predicted for the study area, should mean up to 50% less summer rain by year 2100. We analysed forest responses to increased drought using the model proposed focusing on changes in evapotranspiration, soil moisture and forest structure (above-ground biomass and basal area). We compared the responses of a young stand (YS, ca. 60 years-old) and an old-growth forest (OG, >500 years-old) in the same area. Based on detailed field measurements of water fluxes, the model provides a reliable account of the hydrologic balance of these evergreen, broad-leaved rainforests. We found higher evapotranspiration in OG than YS under current climate. Increasing drought predicted for this century can reduce evapotranspiration by 15% in the OG compared to current values. Drier climate will alter forest structure, leading to decreases in above ground biomass by 27% of the current value in OG. The model presented here can be used to assess the potential impacts of climate change on forest hydrology and other threats of global change on future forests such as fragmentation, introduction of exotic tree species, and changes in fire regimes. Our study expands the applicability of forest dynamics models in remote and hitherto overlooked regions of the world, such as southern temperate rainforests.

  12. Increased drought impacts on temperate rainforests from southern South America: results of a process-based, dynamic forest model.

    Directory of Open Access Journals (Sweden)

    Alvaro G Gutiérrez

    Full Text Available Increased droughts due to regional shifts in temperature and rainfall regimes are likely to affect forests in temperate regions in the coming decades. To assess their consequences for forest dynamics, we need predictive tools that couple hydrologic processes, soil moisture dynamics and plant productivity. Here, we developed and tested a dynamic forest model that predicts the hydrologic balance of North Patagonian rainforests on Chiloé Island, in temperate South America (42°S. The model incorporates the dynamic linkages between changing rainfall regimes, soil moisture and individual tree growth. Declining rainfall, as predicted for the study area, should mean up to 50% less summer rain by year 2100. We analysed forest responses to increased drought using the model proposed focusing on changes in evapotranspiration, soil moisture and forest structure (above-ground biomass and basal area. We compared the responses of a young stand (YS, ca. 60 years-old and an old-growth forest (OG, >500 years-old in the same area. Based on detailed field measurements of water fluxes, the model provides a reliable account of the hydrologic balance of these evergreen, broad-leaved rainforests. We found higher evapotranspiration in OG than YS under current climate. Increasing drought predicted for this century can reduce evapotranspiration by 15% in the OG compared to current values. Drier climate will alter forest structure, leading to decreases in above ground biomass by 27% of the current value in OG. The model presented here can be used to assess the potential impacts of climate change on forest hydrology and other threats of global change on future forests such as fragmentation, introduction of exotic tree species, and changes in fire regimes. Our study expands the applicability of forest dynamics models in remote and hitherto overlooked regions of the world, such as southern temperate rainforests.

  13. Experimental warming does not enhance soil respiration in a semiarid temperate forest-steppe ecosystem

    DEFF Research Database (Denmark)

    Lellei-Kovacs, E.; Kovacs-Lang, E.; Kalapos, T.

    2008-01-01

    The influence of simulated climate change on soil respiration was studied in a field experiment on 4 m x 5 m plots in the semiarid temperate Pannonian sand forest-steppe. This ecosystem type has low productivity and soil organic matter content, and covers large areas, yet data on soil carbon fluxes...... are still limited. Soil respiration rate-measured monthly between April and November from 2003 to 2006-remained very low (0.09 - 1.53 mu mol CO2 m(-2) s(-1))in accordance with the moderate biological activity and low humus content of the nutrient poor, coarse sandy soil. Specific soil respiration rate...... ( calculated for unit soil organic matter content), however, was relatively high (0.36 - 7.92 mu mol CO g(-1) C(org)h(-1)) suggesting substrate limitation for soil biological activity. During the day, soil respiration rate was significantly lower at dawn than at midday, while seasonally clear temperature...

  14. Litter input controls on soil carbon in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Bowden, Richard D.; Deem, Lauren; Plante, Alain F.

    2014-01-01

    Above- and belowground litter inputs in a temperate deciduous forest were altered for 20 yr to determine the importance of leaves and roots on soil C and soil organic matter (SOM) quantity and quality. Carbon and SOM quantity and quality were measured in the O horizon and mineral soil to 50 cm...... in five treatments (control, double litter [DL], no litter [NL], no roots [NR], no inputs [NI]). After two decades of doubled litter addition, soil C and SOM did not increase. However, leaf litter exclusions reduced soil C (O and mineral horizons combined) by 24% in NL and 33% in NI treatments....... In the mineral soil, the largest declines occurred in the 0- to 10-cm depth (0.93-2.01 kg C m-2), although losses were observed throughout the entire solum. The NR treatments showed no losses of C. Thermal characterization of SOM quality differed among treatments in the 0- to 10-cm depth. Patterns of CO2...

  15. Living Trees are a Major Source of Methane in the Temperate Forest

    Science.gov (United States)

    Covey, Kristofer

    2017-04-01

    Globally, forests sequester about 1.1 ± 0.8 Pg C yr-1, an ecosystem service worth hundreds of billions of dollars annually. Following the COP21 meeting in Paris, an international consensus emerged: The protection and expansion of forests worldwide is a necessary component of climate mitigation strategies to limit warming to less than 2°C. The physiological processes governing sequestration of CO2 in living trees are well studied and the resulting pattern in global forest carbon sequestration is clear. The role living trees play in the production and emission of methane (CH4) remains unclear, despite the fact it has the potential to offset climate benefits of forest CO2 sequestration. A known but largely unexplored pathway of forest CH4 production involves microbial-based methanogenesis in the wood of living trees. In the first regional-scale study of tree trunk gas composition, we examine the ubiquity and potential source strength of this pathway. Trunk methane concentrations were as high as 67.4% by volume (375,000-times atmospheric), with the highest concentrations found in older angiosperms (18,293 μLṡL-1 ± 3,096). Bark flux chambers from 23 living trees show emissions under field conditions, and large static chambers demonstrate high rates of production in felled Acer rubrum trunk sections. Diffusion flux modeling of trunk concentrations suggests wood-based microflora could produce a global CH4 efflux of 26 Tg CH4 yr-1. Applying these fluxes to provide a spatially explicit map of trunk-based CH4 flux, we estimate the potential relationship between carbon sequestration rates and CH4 emission by forest trees in Eastern North America. Methane emissions from the trunk-based methanogenic pathway could reduce the average climate mitigation value of these temperate forests by 10-30%. We highlight the need to improve earth systems models to account for the full complexity of forest climate interactions and provide a data layer useful in reducing large uncertainty

  16. Assessment of crown fire initiation and spread models in Mediterranean conifer forests by using data from field and laboratory experiments

    Energy Technology Data Exchange (ETDEWEB)

    Rodríguez y Silva, F.; Guijarro, M.; Madrigal, J.; Jiménez, E.; Molina, J.R.; Hernando, C.; Vélez, R.; Vega, J.A.

    2017-11-01

    Aims of study: To conduct the first full-scale crown fire experiment carried out in a Mediterranean conifer stand in Spain; to use different data sources to assess crown fire initiation and spread models, and to evaluate the role of convection in crown fire initiation. Area of study: The Sierra Morena mountains (Coordinates ETRS89 30N: X: 284793-285038; Y: 4218650-4218766), southern Spain, and the outdoor facilities of the Lourizán Forest Research Centre, northwestern Spain. Material and methods: The full-scale crown fire experiment was conducted in a young Pinus pinea stand. Field data were compared with data predicted using the most used crown fire spread models. A small-scale experiment was developed with Pinus pinaster trees to evaluate the role of convection in crown fire initiation. Mass loss calorimeter tests were conducted with P. pinea needles to estimate residence time of the flame, which was used to validate the crown fire spread model. Main results: The commonly used crown fire models underestimated the crown fire spread rate observed in the full-scale experiment, but the proposed new integrated approach yielded better fits. Without wind-forced convection, tree crowns did not ignite until flames from an intense surface fire contacted tree foliage. Bench-scale tests based on radiation heat flux therefore offer a limited insight to full-scale phenomena. Research highlights: Existing crown fire behaviour models may underestimate the rate of spread of crown fires in many Mediterranean ecosystems. New bench-scale methods based on flame buoyancy and more crown field experiments allowing detailed measurements of fire behaviour are needed.

  17. Concentrations and content of mercury in bark, wood, and leaves in hardwoods and conifers in four forested sites in the northeastern USA.

    Science.gov (United States)

    Yang, Yang; Yanai, Ruth D; Driscoll, Charles T; Montesdeoca, Mario; Smith, Kevin T

    2018-01-01

    Mercury (Hg) is deposited from the atmosphere to remote areas such as forests, but the amount of Hg in trees is not well known. To determine the importance of Hg in trees, we analyzed foliage, bark and bole wood of eight tree species at four sites in the northeastern USA (Huntington Forest, NY; Sleepers River, VT; Hubbard Brook, NH; Bear Brook, ME). Foliar concentrations of Hg averaged 16.3 ng g-1 among the hardwood species, which was significantly lower than values in conifers, which averaged 28.6 ng g-1 (p < 0.001). Similarly, bark concentrations of Hg were lower (p < 0.001) in hardwoods (7.7 ng g-1) than conifers (22.5 ng g-1). For wood, concentrations of Hg were higher in yellow birch (2.1-2.8 ng g-1) and white pine (2.3 ng g-1) than in the other species, which averaged 1.4 ng g-1 (p < 0.0001). Sites differed significantly in Hg concentrations of foliage and bark (p = 0.02), which are directly exposed to the atmosphere, but the concentration of Hg in wood depended more on species (p < 0.001) than site (p = 0.60). The Hg contents of tree tissues in hardwood stands, estimated from modeled biomass and measured concentrations at each site, were higher in bark (mean of 0.10 g ha-1) and wood (0.16 g ha-1) than in foliage (0.06 g ha-1). In conifer stands, because foliar concentrations were higher, the foliar pool tended to be more important. Quantifying Hg in tree tissues is essential to understanding the pools and fluxes of Hg in forest ecosystems.

  18. Trophic cascades, invasive species and body-size hierarchies interactively modulate climate change responses of ecotonal temperate-boreal forest.

    Science.gov (United States)

    Frelich, Lee E; Peterson, Rolf O; Dovčiak, Martin; Reich, Peter B; Vucetich, John A; Eisenhauer, Nico

    2012-11-05

    As the climate warms, boreal tree species are expected to be gradually replaced by temperate species within the southern boreal forest. Warming will be accompanied by changes in above- and below-ground consumers: large moose (Alces alces) replaced by smaller deer (Odocoileus virginianus) above-ground, and small detritivores replaced by larger exotic earthworms below-ground. These shifts may induce a cascade of ecological impacts across trophic levels that could alter the boreal to temperate forest transition. Deer are more likely to browse saplings of temperate tree species, and European earthworms favour seedlings of boreal tree species more than temperate species, potentially hindering the ability of temperate tree species to expand northwards. We hypothesize that warming-induced changes in consumers will lead to novel plant communities by changing the filter on plant species success, and that above- and below-ground cascades of trophic interactions will allow boreal tree species to persist during early phases of warming, leading to an abrupt change at a later time. The synthesis of evidence suggests that consumers can modify the climate change-induced transition of ecosystems.

  19. Breakage or uprooting: How tree death type affects hillslope processes in old-growth temperate forests

    Science.gov (United States)

    Šamonil, Pavel; Daněk, Pavel; Adam, Dušan; Phillips, Jonathan D.

    2017-12-01

    Tree breakage and uprooting are two possible scenarios of tree death that have differing effects on hillslope processes. In this study we aimed to (i) reveal the long-term structure of the biomechanical effects of trees (BETs) in relation to their radial growth and tree death types in four old-growth temperate forests in four different elevation settings with an altitudinal gradient of 152-1105 m a.s.l., (ii) quantify affected areas and soil volumes associated with the studied BETs in reserves, and (iii) derive a general model of the role of BETs in hillslope processes in central European temperate forests. We analyzed the individual dynamics of circa 55,000 trees in an area of 161 ha within four old-growth forests over 3-4 decades. Basal tree censuses established in all sites in the 1970s and repeated tree censuses in the 1990s and 2000s provided detailed information about the radial growth of each tree of DBH ≥ 10 cm as well as about types of tree death. We focused on the quantification of: (i) surviving still-living trees, (ii) new recruits, (iii) standing dead trees, (iv) uprooted trees, and (v) broken trees. Frequencies of phenomena were related to affected areas and volumes of soil using individual statistical models. The elevation contrasts were a significant factor in the structure of BETs. Differences between sites increased from frequencies of events through affected areas to volumes of soil associated with BETs. An average 2.7 m3 ha-1 year-1 was associated with all BETs of the living and dying trees in lowlands, while there was an average of 7.8 m3 ha-1 year-1 in the highest mountain site. Differences were caused mainly by the effects of dying trees. BETs associated with dead trees were 7-8 times larger in the mountains. Effects of dying trees and particularly treethrows represented about 70% of all BETs at both mountain sites, while it was 58% at the highland site and only 32% at the lowland site. Our results show a more significant role of BETs in

  20. Can Earthworm "mix up" Soil Carbon Budgets in Temperate Forests Under Elevated Carbon Dioxide?

    Science.gov (United States)

    Sánchez-de León, Y.; González-Meler, M.; Sturchio, N. C.; Wise, D. H.; Norby, R. J.

    2008-12-01

    The effects of global change on earthworms and their associated feedbacks on soil and ecosystem processes have been largely overlooked. We studied how the responses of a temperate deciduous forest to elevated carbon dioxide atmospheric concentrations (e[CO2]) influence earthworms and the soil processes affected by them. Our objectives were to: i) identify soil layers of active soil mixing under e[CO2] and current carbon dioxide atmospheric concentrations (c[CO2]) using fallout cesium (137Cs), ii) study how e[CO2] affects earthworm populations, iii) understand the relationship between soil mixing and earthworms at our study site, and iv) identify the implications of earthworm-mediated soil mixing for the carbon budget of a temperate forest. To study soil mixing, we measured vertical 137Cs activity in soil cores (0-24 cm depth) collected in replicated e[CO2] and c[CO2] sweetgum (Liquidambar styraciflua) plots (n = 2) in a Free Air CO2 Enrichment (FACE) ecosystem experiment at Oak Ridge National Laboratory. We measured earthworm density and fresh weight in the plots in areas adjacent to where soil cores were taken. Preliminary results on the vertical distribution of 137Cs in the c[CO2] treatments showed that higher 137Cs activity was located from 8-16 cm depth and no 137Cs activity was measured below 20 cm. In contrast, in the e[CO2] treatment, peak 137Cs activity was slightly deeper (10-18 cm), and 137Cs activity was still measured below 22 cm. Mean earthworm density was higher in e[CO2] than c[CO2] treatments (168 m-2 and 87 m-2, respectively; p = 0.046); earthworm fresh weights, however, did not differ significantly between treatments (32 g m-2 and 18 g m-2, respectively; p = 0.182). The 137Cs vertical distribution suggest that soil mixing occurs deeper in e[CO2] than in c[CO2] treatments, which is consistent with higher earthworm densities in e[CO2] than in c[CO2] treatments. Mixing deeper low carbon content soil with shallower high carbon soil may result in a

  1. Invasion by the Alien Tree Prunus serotina Alters Ecosystem Functions in a Temperate Deciduous Forest

    Science.gov (United States)

    Aerts, Raf; Ewald, Michael; Nicolas, Manuel; Piat, Jérôme; Skowronek, Sandra; Lenoir, Jonathan; Hattab, Tarek; Garzón-López, Carol X.; Feilhauer, Hannes; Schmidtlein, Sebastian; Rocchini, Duccio; Decocq, Guillaume; Somers, Ben; Van De Kerchove, Ruben; Denef, Karolien; Honnay, Olivier

    2017-01-01

    Alien invasive species can affect large areas, often with wide-ranging impacts on ecosystem structure, function, and services. Prunus serotina is a widespread invader of European temperate forests, where it tends to form homogeneous stands and limits recruitment of indigenous trees. We hypotesized that invasion by P. serotina would be reflected in the nutrient contents of the native species' leaves and in the respiration of invaded plots as efficient resource uptake and changes in nutrient cycling by P. serotina probably underly its aggressive invasiveness. We combined data from 48 field plots in the forest of Compiègne, France, and data from an experiment using 96 microcosms derived from those field plots. We used general linear models to separate effects of invasion by P. serotina on heterotrophic soil and litter respiration rates and on canopy foliar nutrient content from effects of soil chemical properties, litter quantity, litter species composition, and tree species composition. In invaded stands, average respiration rates were 5.6% higher for soil (without litter) and 32% higher for soil and litter combined. Compared to indigenous tree species, P. serotina exhibited higher foliar N (+24.0%), foliar P (+50.7%), and lower foliar C:N (−22.4%) and N:P (−10.1%) ratios. P. serotina affected foliar nutrient contents of co-occuring indigenous tree species leading to decreased foliar N (−8.7 %) and increased C:N ratio (+9.5%) in Fagus sylvatica, decreased foliar N:P ratio in Carpinus betulus (−13.5%) and F. sylvatica (−11.8%), and increased foliar P in Pinus sylvestris (+12.3%) in invaded vs. uninvaded stands. Our results suggest that P. serotina is changing nitrogen, phosphorus, and carbon cycles to its own advantage, hereby increasing carbon turnover via labile litter, affecting the relative nutrient contents in the overstory leaves, and potentially altering the photosynthetic capacity of the long-lived indigenous broadleaved species. Uncontrolled

  2. DEVELOPMENT OF SMART PRECISION FOREST IN CONIFER PLANTATION IN JAPAN USING LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    M. Katoh

    2017-10-01

    Full Text Available Currently, the authors are planning to launch a consortium effort toward Japan’s first smart precision forestry project using laser data and to develop this technology throughout the country. Smart precision forestry information gathered using the Nagano model (laser scanning from aircraft, drone, and backpack is being developed to improve the sophistication of forest information, reduce labor-intensive work, maintain sustainable timber productivity, and facilitate supply chain management by laser sensing information in collaboration with industry, academia, and government. In this paper, we outline the research project and the technical development situation of unmanned aerial vehicle laser scanning.

  3. Development of Smart Precision Forest in Conifer Plantation in Japan Using Laser Scanning Data

    Science.gov (United States)

    Katoh, M.; Deng, S.; Takenaka, Y.; Cheung, K.; Oono, K.; Horisawa, M.; Hyyppä, J.; Yu, X.; Liang, X.; Wang, Y.

    2017-10-01

    Currently, the authors are planning to launch a consortium effort toward Japan's first smart precision forestry project using laser data and to develop this technology throughout the country. Smart precision forestry information gathered using the Nagano model (laser scanning from aircraft, drone, and backpack) is being developed to improve the sophistication of forest information, reduce labor-intensive work, maintain sustainable timber productivity, and facilitate supply chain management by laser sensing information in collaboration with industry, academia, and government. In this paper, we outline the research project and the technical development situation of unmanned aerial vehicle laser scanning.

  4. Empirical and simulated critical loads for nitrogen deposition in California mixed conifer forests

    International Nuclear Information System (INIS)

    Fenn, M.E.; Jovan, S.; Yuan, F.; Geiser, L.; Meixner, T.; Gimeno, B.S.

    2008-01-01

    Empirical critical loads (CL) for N deposition were determined from changes in epiphytic lichen communities, elevated NO 3 - leaching in streamwater, and reduced fine root biomass in ponderosa pine (Pinus ponderosa Dougl. ex Laws.) at sites with varying N deposition. The CL for lichen community impacts of 3.1 kg ha -1 year -1 is expected to protect all components of the forest ecosystem from the adverse effects of N deposition. Much of the western Sierra Nevada is above the lichen-based CL, showing significant changes in lichen indicator groups. The empirical N deposition threshold and that simulated by the DayCent model for enhanced NO 3 - leaching were 17 kg N ha -1 year -1 . DayCent estimated that elevated NO 3 - leaching in the San Bernardino Mountains began in the late 1950s. Critical values for litter C:N (34.1), ponderosa pine foliar N (1.1%), and N concentrations (1.0%) in the lichen Letharia vulpina ((L.) Hue) are indicative of CL exceedance. - Critical loads for N deposition effects on lichens, trees and nitrate leaching provide benchmarks for protecting California forests

  5. Drought timing and local climate determine the sensitivity of eastern temperate forests to drought.

    Science.gov (United States)

    D'Orangeville, Loïc; Maxwell, Justin; Kneeshaw, Daniel; Pederson, Neil; Duchesne, Louis; Logan, Travis; Houle, Daniel; Arseneault, Dominique; Beier, Colin M; Bishop, Daniel A; Druckenbrod, Daniel; Fraver, Shawn; Girard, François; Halman, Joshua; Hansen, Chris; Hart, Justin L; Hartmann, Henrik; Kaye, Margot; Leblanc, David; Manzoni, Stefano; Ouimet, Rock; Rayback, Shelly; Rollinson, Christine R; Phillips, Richard P

    2018-02-20

    Projected changes in temperature and drought regime are likely to reduce carbon (C) storage in forests, thereby amplifying rates of climate change. While such reductions are often presumed to be greatest in semi-arid forests that experience widespread tree mortality, the consequences of drought may also be important in temperate mesic forests of Eastern North America (ENA) if tree growth is significantly curtailed by drought. Investigations of the environmental conditions that determine drought sensitivity are critically needed to accurately predict ecosystem feedbacks to climate change. We matched site factors with the growth responses to drought of 10,753 trees across mesic forests of ENA, representing 24 species and 346 stands, to determine the broad-scale drivers of drought sensitivity for the dominant trees in ENA. Here we show that two factors-the timing of drought, and the atmospheric demand for water (i.e., local potential evapotranspiration; PET)-are stronger drivers of drought sensitivity than soil and stand characteristics. Drought-induced reductions in tree growth were greatest when the droughts occurred during early-season peaks in radial growth, especially for trees growing in the warmest, driest regions (i.e., highest PET). Further, mean species trait values (rooting depth and ψ 50 ) were poor predictors of drought sensitivity, as intraspecific variation in sensitivity was equal to or greater than interspecific variation in 17 of 24 species. From a general circulation model ensemble, we find that future increases in early-season PET may exacerbate these effects, and potentially offset gains in C uptake and storage in ENA owing to other global change factors. © 2018 John Wiley & Sons Ltd.

  6. Mechanisms underlying local functional and phylogenetic beta diversity in two temperate forests.

    Science.gov (United States)

    Wang, Xugao; Wiegand, Thorsten; Swenson, Nathan G; Wolf, Amy T; Howe, Robert W; Hao, Zhanqing; Lin, Fei; Ye, Ji; Yuan, Zuoqiang

    2015-04-01

    Although trait information has been widely used to explore underlying mechanisms of forest community structure, most studies have focused on local patterns of phylogenetic or functional alpha diversity. Investigations of functional beta diversity, on the other hand, have not been conducted at local scales in a spatially explicit way. In this study, we provide a powerful methodology based on recent advances in spatial point pattern analysis using fully mapped data of large and small trees in two large temperate forest plots. This approach allowed us to assess the relative importance of different ecological processes and mechanisms for explaining patterns of local phylogenetic and functional beta diversity. For both forests and size classes, we found a clear hierarchy of scales: habitat filtering accounted for patterns of phylogenetic and functional beta diversity at larger distances (150-250 m), dispersal limitation accounted for the observed decline in beta diversity at distances below 150 m, and species interactions explained small departures from functional and phylogenetic beta diversity at the immediate plant-neighborhood scale (below 20 m). Thus, both habitat filtering and dispersal limitation influenced the observed patterns in phylogenetic and functional beta diversity at local scales. This result contrasts with a previous study from the same forests, where dispersal limitation alone approximated the observed species beta diversity for distances up to 250 m. In addition, species interactions were relatively unimportant for predicting phylogenetic and functional beta diversity. Our analysis suggests that phylogenetic and functional beta diversity can provide insights into the mechanisms of local community assembly that are missed by studies focusing exclusively on species beta diversity.

  7. Early impacts of forest restoration treatments on the ectomycorrhizal fungal community and fine root biomass in a mixed conifer forest.

    Science.gov (United States)

    Jane E. Smith; Donaraye McKay; Greg Brenner; Jim McIver; Joseph W. Spatafora

    2005-01-01

    1. The obligate symbiosis formed between ectomycorrhizal fungi (EMF) and roots of tree species in the Pinaceae influences nutrient uptake and surrounding soil structure. Understanding how EMF respond to prescribed fire and thinning will assist forest managers in selecting fuel-reducing restoration treatments that maintain critical soil processes and site productivity....

  8. Litter type control on soil C and N stabilization dynamics in a temperate forest.

    Science.gov (United States)

    Hatton, Pierre-Joseph; Castanha, Cristina; Torn, Margaret S; Bird, Jeffrey A

    2015-03-01

    While plant litters are the main source of soil organic matter (SOM) in forests, the controllers and pathways to stable SOM formation remain unclear. Here, we address how litter type ((13) C/(15) N-labeled needles vs. fine roots) and placement-depth (O vs. A horizon) affect in situ C and N dynamics in a temperate forest soil after 5 years. Litter type rather than placement-depth controlled soil C and N retention after 5 years in situ, with belowground fine root inputs greatly enhancing soil C (x1.4) and N (x1.2) retention compared with aboveground needles. While the proportions of added needle and fine root-derived C and N recovered into stable SOM fractions were similar, they followed different transformation pathways into stable SOM fractions: fine root transfer was slower than for needles, but proportionally more of the remaining needle-derived C and N was transferred into stable SOM fractions. The stoichiometry of litter-derived C vs. N within individual SOM fractions revealed the presence at least two pools of different turnover times (per SOM fraction) and emphasized the role of N-rich compounds for long-term persistence. Finally, a regression approach suggested that models may underestimate soil C retention from litter with fast decomposition rates. © 2014 John Wiley & Sons Ltd.

  9. Impacts of fire exclusion and recent managed fire on forest structure in old growth Sierra Nevada mixed-conifer forests

    Science.gov (United States)

    Brandon M. Collins; Richard G. Everett; Scott L. Stephens

    2011-01-01

    We re-sampled areas included in an unbiased 1911 timber inventory conducted by the U.S. Forest Service over a 4000 ha study area. Over half of the re-sampled area burned in relatively recent management- and lightning-ignited fires. This allowed for comparisons of both areas that have experienced recent fire and areas with no recent fire, to the same areas historically...

  10. Value of Old Forest Attributes Related to Cryptogam Species Richness in Temperate Forests: A Quantitative Assessment

    Czech Academy of Sciences Publication Activity Database

    Hofmeister, J.; Hošek, J.; Brabec, Marek; Dvořák, D.; Beran, M.; Deckerová, H.; Burel, J.; Kříž, M.; Borovička, Jan; Běťák, J.; Vašutová, M.; Malíček, J.; Palice, Zdeněk; Syrovátková, L.; Steinová, J.; Černajová, I.; Holá, E.; Novozámská, E.; Čížek, L.; Iarema, V.; Baltaziuk, K.; Svoboda, T.

    2015-01-01

    Roč. 57, October (2015), s. 497-504 ISSN 1470-160X Grant - others:GA MŽP(CZ) SP/2D1/146/08 Institutional support: RVO:67985807 ; RVO:67985831 ; RVO:67985939 Keywords : Bryophytes * Dead wood * Forest structure * Lichens * Macrofungi * Size-dependent coefficient model Subject RIV: BB - Applied Statistics, Operational Research; EF - Botanics (BU-J); EF - Botanics (GLU-S) Impact factor: 3.190, year: 2015

  11. Tropical and Highland Temperate Forest Plantations in Mexico: Pathways for Climate Change Mitigation and Ecosystem Services Delivery

    Directory of Open Access Journals (Sweden)

    Vidal Guerra-De la Cruz

    2017-12-01

    Full Text Available Forest plantations are a possible way of increasing forest productivity in temperate and tropical forests, and therefore also increasing above- and belowground carbon pools. In the context of climate change, monospecific plantations might become an alternative to mitigate global warming; however, their contribution to the structural complexity, complementarity, and biodiversity of forests has not been addressed. Mixed forest plantations can ensure that objectives of climate change mitigation are met through carbon sequestration, while also delivering anticipated ecosystem services (e.g., nutrient cycling, erosion control, and wildlife habitat. However, mixed forest plantations pose considerable operational challenges and research opportunities. For example, it is essential to know how many species or functional traits are necessary to deliver a set of benefits, or what mixture of species and densities are key to maintaining productive plantations and delivering multiple ecosystem services. At the same time, the establishment of forest plantations in Mexico should not be motivated solely by timber production. Forest plantations should also increase carbon sequestration, maintain biodiversity, and provide other ecosystem services. This article analyzes some matters that affect the development of planted forests in the Mexican national context, and presents alternatives for forest resources management through the recommendation of mixed forest plantations as a means of contributing to climate change mitigation and the delivery of ecosystem services.

  12. Impacts of cloud immersion on microclimate, photosynthesis and water relations of Abies fraseri (Pursh.) Poiret in a temperate mountain cloud forest.

    Science.gov (United States)

    Reinhardt, Keith; Smith, William K

    2008-11-01

    The red spruce-Fraser fir ecosystem [Picea rubens Sarg.-Abies fraseri (Pursh) Poir.] of the southern Appalachian mountains, USA, is a temperate zone cloud forest immersed in clouds for 30-40% of a typical summer day, and experiencing immersion on about 65% of all days annually. We compared the microclimate, photosynthetic gas exchange, and water relations of Fraser fir trees in open areas during cloud-immersed, low-cloud, or sunny periods. In contrast to sunny periods, cloud immersion reduced instantaneous sunlight irradiance by 10-50%, and midday atmospheric vapor pressure deficit (VPD) was 85% lower. Needle surfaces were wet for up to 16 h per day during cloud-immersed days compared to <1 h for clear days. Shoot-level light-saturated photosynthesis (A (sat)) on both cloud-immersed (16.0 micromol m(-2) s(-1)) and low-cloud (17.9 micromol m(-2) s(-1)) days was greater than A (sat) on sunny days (14.4 micromol m(-2) s(-1)). Daily mean A was lowest on cloud-immersed days due to reduced sunlight levels, while leaf conductance (g) was significantly higher, with a mean value of 0.30 mol m(-2) s(-1). These g values were greater than commonly reported for conifer tree species with needle-like leaves, and declined exponentially with increasing leaf-to-air VPD. Daily mean transpiration (E) on immersed days was 43 and 20% lower compared to sunny and low-cloud days, respectively. As a result, daily mean water use efficiency (A/E) was lowest on cloud-immersed days due to light limitation of A, and high humidity resulted in greater uncoupling of A from g. Thus, substantial differences in photosynthetic CO2 uptake, and corresponding water relations, were strongly associated with cloud conditions that occur over substantial periods of the summer growth season.

  13. Ecosystem Respiration in an Undisturbed, Old-Growth, Temperate Rain Forest

    Science.gov (United States)

    Hunt, J. E.; Walcroft, A. S.; McSeveny, T. M.; Rogers, G. N.; Whitehead, D.

    2008-12-01

    Old-growth forests are usually close to carbon neutral, and climate change may push them towards becoming net carbon sources. Ecosystem carbon exchange and its component fluxes, were measured in a temperate rainforest in South Westland, New Zealand. The forest, which receives over 3 m of rain a year, is dominated by 400 year-old podocarp trees, and is on a low nutrient, acidic, peat soil. Nighttime respiration measurements using eddy covariance were problematic due to katabatic induced CO2 drainage flows near the ground and low turbulence. Instead of the friction velocity filtering technique, we used the maximum eddy flux within a few hours of sunset to derive a function relating nighttime ecosystem respiration to soil temperature. The function was then used to calculate respiration for the nighttime periods. Soil respiration was measured at regular intervals during the growing season. Soil temperature was regulated by incoming radiation and changes in the soil heat capacity. The water table was typically only 160 mm below the ground surface. Soil respiration (mean = 2.9 μmol m-2 s-1) increased strongly with both an increase in soil temperature and an increase in the depth to the water table, and accounted for approximately 50% of ecosystem respiration. Changes in the water table depth caused by altered rainfall regime, evaporation and drainage are likely to have a significant effect on the soil respiration rate and carbon balance of this old-growth forest. Foliage and stem respiration were also measured and integrated to the canopy scale using a model. The model was then used to decompose ecosystem respiration measurements into its components. A combination of measured and modelled data indicates that the ecosystem is a net source for carbon (-0.34 kg C m&-2 yr-1).

  14. Narrowband Bio-Indicator Monitoring of Temperate Forest Carbon Fluxes in Northeastern China

    Directory of Open Access Journals (Sweden)

    Quanzhou Yu

    2014-09-01

    Full Text Available Developments in hyperspectral remote sensing techniques during the last decade have enabled the use of narrowband indices to evaluate the role of forest ecosystem variables in estimating carbon (C fluxes. In this study, narrowband bio-indicators derived from EO-1 Hyperion data were investigated to determine whether they could capture the temporal variation and estimate the spatial variability of forest C fluxes derived from eddy covariance tower data. Nineteen indices were divided into four categories of optical indices: broadband, chlorophyll, red edge, and light use efficiency. Correlation tests were performed between the selected vegetation indices, gross primary production (GPP, and ecosystem respiration (Re. Among the 19 indices, five narrowband indices (Chlorophyll Index RedEdge 710, scaled photochemical reflectance index (SPRI*enhanced vegetation index (EVI, SPRI*normalized difference vegetation index (NDVI, MCARI/OSAVI[705, 750] and the Vogelmann Index, and one broad band index (EVI had R-squared values with a good fit for GPP and Re. The SPRI*NDVI has the highest significant coefficients of determination with GPP and Re (R2 = 0.86 and 0.89, p < 0.0001, respectively. SPRI*NDVI was used in atmospheric inverse modeling at regional scales for the estimation of C fluxes. We compared the GPP spatial patterns inversed from our model with corresponding results from the Vegetation Photosynthesis Model (VPM, the Boreal Ecosystems Productivity Simulator model, and MODIS MOD17A2 products. The inversed GPP spatial patterns from our model of SPRI*NDVI had good agreement with the output from the VPM model. The normalized difference nitrogen index was well correlated with measured C net ecosystem exchange. Our findings indicated that narrowband bio-indicators based on EO-1 Hyperion images could be used to predict regional C flux variations for Northeastern China’s temperate broad-leaved Korean pine forest ecosystems.

  15. EMERGY-based environmental systems assessment of a multi-purpose temperate mixed-forest watershed of the southern Appalachian Mountains, USA

    Science.gov (United States)

    David Rogers Tilley; Wayne T. Swank

    2003-01-01

    Emergy (with an 'm') synthesis was used to assess the balance between nature and humanity and the equity among forest outcomes of a US Forest Service ecosystem management demonstration project on the Wine Spring Creek watershed, a high-elevation (1600 m), temperate forest located in the southern Appalachian mountains of North Carolina, USA. EM embraces a...

  16. Responses of Sap Flow of Deciduous and Conifer Trees to Soil Drying in a Subalpine Forest

    Directory of Open Access Journals (Sweden)

    Chunhua Yan

    2018-01-01

    Full Text Available Co-occurring species may adopt different water-use strategies to adapt to limited soil water. In Jiuzhaigou Valley, a continuous decline in soil water after an initial recharge from the thawing of snow and frozen soil in early spring was observed, but its effects on the sap flow dynamics of co-occurring species are not well understood. To clarify the species-specific water-use strategy, variations in sap flow and environmental conditions were investigated for two co-occurring species (Betula albosinensis Burk. and Pinus tabuliaeformis Carr. in a mixed forest during a transition from the wet to dry period in 2014. Sap flow was measured using Granier-type thermal dissipation probes, and the soil-water content was measured using time-domain reflectometry probes for a successive period. Our study showed that B. albosinensis maintained relatively high transpiration until late into the season regardless of soil moisture, while the transpiration of P. tabuliformis showed a continuous decrease in response to seasonal soil drying. Sap flow for both species exhibited a marked hysteresis in response to meteorological factors and it was conditioned by the soil-water status, especially in the afternoon. We found that P. tabuliformis was sensitive to soil-water conditions, while for B. albosinensis, the sap flow was not very sensitive to changes in soil-water conditions. These results indicate that B. albosinensis could manage the water consumption conservatively under both dry and wet conditions. These results may have implications for evaluating the species-specific water-use strategy and carrying out proper reforestation practices.

  17. Determinants of conifer distributions across peatland to forest gradients in the coastal temperate rainforest of southeast Alaska

    Science.gov (United States)

    Sarah M. Bisbing; David J. Cooper; David V. D' Amore; Kristin N. Marshall

    2016-01-01

    Wetland determination relies on assumptions that site hydrologic and edaphic conditions limit plant species to certain environments. For example, using species' wetland indicator status for wetland determination assumes that tolerance of wetland conditions best explains distributional patterns. However, abiotic and biotic factors often interact to create complex...

  18. Water isotope partitioning and ecohydrologic separation in mixed conifer forest explored with a centrifugation water extraction method

    Science.gov (United States)

    Bowers, W.; Mercer, J.; Pleasants, M.; Williams, D. G.

    2017-12-01

    Isotopic partitioning of water within soil into tightly and loosely bound fractions has been proposed to explain differences between isotopic water sources used by plants and those that contribute to streams and ground water, the basis for the "two water worlds" hypothesis. We examined the isotope ratio values of water in trees, bulk soil, mobile water collected from soil lysimeters, stream water, and GW at three different hillslopes in a mixed conifer forest in southeastern Wyoming, USA. Hillslopes differed in aspect and topographic position with corresponding differences in surface energy balance, snowmelt timing, and duration of soil moisture during the dry summer. The isotopic results support the partitioning of water within the soil; trees apparently used a different pool of water for transpiration than that recovered from soil lysimeters and the source was not resolved with the isotopic signature of the water that was extracted from bulk soil via cryogenic vacuum distillation. Separating and measuring the isotope ratios values in these pools would test the assumption that the tightly bound water within the soil has the same isotopic signature as the water transpired by the trees. We employed a centrifugation approach to separate water within the soil held at different tensions by applying stepwise increases in rotational velocity and pressures to the bulk soil samples. Effluent and the remaining water (cryogenically extracted) at each step were compared. We first applied the centrifugation method in a simple lab experiment using sandy loam soil and separate introductions of two isotopically distinct waters. We then applied the method to soil collected from the montane hillslopes. For the lab experiment, we predicted that effluents would have distinct isotopic signatures, with the last effluent and extracted water more closely representing the isotopic signature of the first water applied. For our field samples, we predicted that the isotopic signature of the

  19. Examining the Physical Drivers of Photosynthetic Temperature Sensitivity Within a Sub-alpine Mixed Conifer Forest

    Science.gov (United States)

    Yang, J.; Barron-Gafford, G.; Minor, R.; Heard, M.

    2013-12-01

    temperatures. This variability in the temperature sensitivity and the responsiveness of that sensitivity to increases in available soil moisture is important as we consider the structure and composition of our future forests. More detailed analysis will allow us to examine the relative influence of each abiotic variable in driving this photosynthetic response, which impacts a suite of downstream critical zone processes.

  20. Variation in carbon stocks on different slope aspects in seven major forest types of temperate region of Garhwal Himalaya, India.

    Science.gov (United States)

    Sharma, C M; Gairola, Sumeet; Baduni, N P; Ghildiyal, S K; Suyal, Sarvesh

    2011-09-01

    The present study was undertaken in seven major forest types of temperate zone (1500 m a.s.l. to 3100 m a.s.l.) of Garhwal Himalaya to understand the effect of slope aspects on carbon (C) density and make recommendations for forest management based on priorities for C conservation/sequestration. We assessed soil organic carbon (SOC) density, tree density, biomass and soil organic carbon (SOC) on four aspects, viz. north/east (NE), north/west (NW), south-east (SE) and south-west (SW), in forest stands dominated by Abies pindrow, Cedrus deodara, Pinus roxburghii, Cupressus torulosa, Quercus floribunda, Quercus semecarpifolia and Quercus leucotrichophora. TCD ranged between 77.3 CMg ha⁻¹ on SE aspect (Quercus leucotrichophora forest) and 291.6 CMg ha⁻¹ on NE aspect (moist Cedrus deodara forest). SOC varied between 40.3 CMg ha⁻¹ on SW aspect (Himalayan Pinus roxburghii forest) and 177.5 CMg ha⁻¹ on NE aspect (moist Cedrus deodara forest). Total C density (SOC+TCD) ranged between 118.1 CMg ha⁻¹ on SW aspect (Himalayan Pinus roxburghii forest) and 469.1 CMg ha⁻¹ on NE aspect (moist Cedrus deodara forest). SOC and TCD were significantly higher on northern aspects as compared with southern aspects. It is recommended that for C sequestration, the plantation silviculture be exercised on northern aspects, and for C conservation purposes, mature forest stands growing on northern aspects be given priority.

  1. Greater diversity of soil fungal communities and distinguishable seasonal variation in temperate deciduous forests compared with subtropical evergreen forests of eastern China.

    Science.gov (United States)

    He, Jinhong; Tedersoo, Leho; Hu, Ang; Han, Conghai; He, Dan; Wei, Hui; Jiao, Min; Anslan, Sten; Nie, Yanxia; Jia, Yongxia; Zhang, Gengxin; Yu, Guirui; Liu, Shirong; Shen, Weijun

    2017-07-01

    Whether and how seasonality of environmental variables impacts the spatial variability of soil fungal communities remain poorly understood. We assessed soil fungal diversity and community composition of five Chinese zonal forests along a latitudinal gradient spanning 23°N to 42°N in three seasons to address these questions. We found that soil fungal diversity increased linearly or parabolically with latitude. The seasonal variations in fungal diversity were more distinguishable in three temperate deciduous forests than in two subtropical evergreen forests. Soil fungal diversity was mainly correlated with edaphic factors such as pH and nutrient contents. Both latitude and its interactions with season also imposed significant impacts on soil fungal community composition (FCC), but the effects of latitude were stronger than those of season. Vegetational properties such as plant diversity and forest age were the dominant factors affecting FCC in the subtropical evergreen forests while edaphic properties were the dominant ones in the temperate deciduous forests. Our results indicate that latitudinal variation patterns of soil fungal diversity and FCC may differ among seasons. The stronger effect of latitude relative to that of season suggests a more important influence by the spatial than temporal heterogeneity in shaping soil fungal communities across zonal forests. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. The longevity of broadleaf deciduous trees in Northern Hemisphere temperate forests: insights from tree-ring series

    Directory of Open Access Journals (Sweden)

    Alfredo eDi Filippo

    2015-05-01

    Full Text Available Understanding the factors controlling the expression of longevity in trees is still an outstanding challenge for tree biologists and forest ecologists. We gathered tree-ring data and literature for broadleaf deciduous (BD temperate trees growing in closed-canopy old-growth forests in the Northern Hemisphere to explore the role of geographic patterns, climate variability, and growth rates on longevity. Our pan-continental analysis, covering 32 species from 12 genera, showed that 300-400 years can be considered a baseline threshold for maximum tree lifespan in many temperate deciduous forests. Maximum age varies greatly in relation to environmental features, even within the same species. Tree longevity is generally promoted by reduced growth rates across large genetic differences and environmental gradients. We argue that slower growth rates, and the associated smaller size, provide trees with an advantage against biotic and abiotic disturbance agents, supporting the idea that size, not age, is the main constraint to tree longevity. The oldest trees were living most of their life in subordinate canopy conditions and/or within primary forests in cool temperate environments and outside major storm tracks. Very old trees are thus characterized by slow growth and often live in forests with harsh site conditions and infrequent disturbance events that kill much of the trees. Temperature inversely controls the expression of longevity in mesophilous species (Fagus spp., but its role in Quercus spp. is more complex and warrants further research in disturbance ecology. Biological, ecological and historical drivers must be considered to understand the constraints imposed to longevity within different forest landscapes.

  3. Robustness of plant-insect herbivore interaction networks to climate change in a fragmented temperate forest landscape.

    Science.gov (United States)

    Bähner, K W; Zweig, K A; Leal, I R; Wirth, R

    2017-10-01

    Forest fragmentation and climate change are among the most severe and pervasive forms of human impact. Yet, their combined effects on plant-insect herbivore interaction networks, essential components of forest ecosystems with respect to biodiversity and functioning, are still poorly investigated, particularly in temperate forests. We addressed this issue by analysing plant-insect herbivore networks (PIHNs) from understories of three managed beech forest habitats: small forest fragments (2.2-145 ha), forest edges and forest interior areas within three continuous control forests (1050-5600 ha) in an old hyper-fragmented forest landscape in SW Germany. We assessed the impact of forest fragmentation, particularly edge effects, on PIHNs and the resulting differences in robustness against climate change by habitat-wise comparison of network topology and biologically realistic extinction cascades of networks following scores of vulnerability to climate change for the food plant species involved. Both the topological network metrics (complexity, nestedness, trophic niche redundancy) and robustness to climate change strongly increased in forest edges and fragments as opposed to the managed forest interior. The nature of the changes indicates that human impacts modify network structure mainly via host plant availability to insect herbivores. Improved robustness of PIHNs in forest edges/small fragments to climate-driven extinction cascades was attributable to an overall higher thermotolerance across plant communities, along with positive effects of network structure. The impoverishment of PIHNs in managed forest interiors and the suggested loss of insect diversity from climate-induced co-extinction highlight the need for further research efforts focusing on adequate silvicultural and conservation approaches.

  4. Do multiple fires interact to affect vegetation structure in temperate eucalypt forests?

    Science.gov (United States)

    Haslem, Angie; Leonard, Steve W J; Bruce, Matthew J; Christie, Fiona; Holland, Greg J; Kelly, Luke T; MacHunter, Josephine; Bennett, Andrew F; Clarke, Michael F; York, Alan

    2016-12-01

    Fire plays an important role in structuring vegetation in fire-prone regions worldwide. Progress has been made towards documenting the effects of individual fire events and fire regimes on vegetation structure; less is known of how different fire history attributes (e.g., time since fire, fire frequency) interact to affect vegetation. Using the temperate eucalypt foothill forests of southeastern Australia as a case study system, we examine two hypotheses about such interactions: (1) post-fire vegetation succession (e.g., time-since-fire effects) is influenced by other fire regime attributes and (2) the severity of the most recent fire overrides the effect of preceding fires on vegetation structure. Empirical data on vegetation structure were collected from 540 sites distributed across central and eastern Victoria, Australia. Linear mixed models were used to examine these hypotheses and determine the relative influence of fire and environmental attributes on vegetation structure. Fire history measures, particularly time since fire, affected several vegetation attributes including ground and canopy strata; others such as low and sub-canopy vegetation were more strongly influenced by environmental characteristics like rainfall. There was little support for the hypothesis that post-fire succession is influenced by fire history attributes other than time since fire; only canopy regeneration was influenced by another variable (fire type, representing severity). Our capacity to detect an overriding effect of the severity of the most recent fire was limited by a consistently weak effect of preceding fires on vegetation structure. Overall, results suggest the primary way that fire affects vegetation structure in foothill forests is via attributes of the most recent fire, both its severity and time since its occurrence; other attributes of fire regimes (e.g., fire interval, frequency) have less influence. The strong effect of environmental drivers, such as rainfall and

  5. Temperate forest impacts on maritime snowpacks across an elevation gradient: An assessment of the snow surface energy balance and airborne lidar derived forest structure

    Science.gov (United States)

    Roth, T. R.; Nolin, A. W.

    2016-12-01

    Temperate forests modify snow evolution patterns both spatially and temporally relative to open areas. Dense, warm forests both impede snow accumulation through increased canopy snow interception and increase sub-canopy longwave energy inputs onto the snow surface. These process modifications vary in magnitude and duration depending on climatic, topographic and forest characteristics. Here we present results from a four year study of paired forested and open sites at three elevations, Low - 1150 m, Mid - 1325 m and High - 1465 m. Snowpacks are deeper and last up to 3-4 weeks longer at the Low and Mid elevation Open sites relative to the adjacent Forest sites. Conversely, at the High Forest site, snow is retained 2-4 weeks longer than the Open site. This change in snowpack depth and persistence is attributed to deposition patterns at higher elevations and forest structure differences that alter the canopy interception efficiency and the sub-canopy energy balance. Canopy interception efficiency (CIE) in the Low and Mid Forest sites, over the duration of the study were 79% and 76% of the total event snowfall, whereas CIE was 31% at the High Forest site. Longwave radiation in forested environments is the primary energy component across each elevation band due to the warm winter environment and forest presence, accounting for 82%, 88%, and 59% of the energy balance at the Low, Mid, and High Forest sites, respectively. High wind speeds in the High elevation Open site significantly increases the turbulent energy and creates preferential snowfall deposition in the nearby Forest site. These results show the importance of understanding the effects of forest cover on sub-canopy snowpack evolution and highlight the need for improved forest cover model representation to accurately predict water resources in maritime forests.

  6. Direct in situ measurement of Carbon Allocation to Mycorrhizal Fungi in a California Mixed-Conifer Forest

    Science.gov (United States)

    Allen, M. F.

    2011-12-01

    Mycorrhizal fungi represent a large allocation of C to ecosystems, based on indirect measurements (tree girdling) and glasshouse extrapolations. However, we have no direct measures carbon (C) sink, in part because technologies for studying belowground dynamics on time scales at which roots and microbes grow and die have not existed. We initiated new sensor and observation platforms belowground to characterize and quantify belowground dynamics in a California mixed-conifer ecosystem. For the first time, we directly observed growth and mortality of mycorrhizal fungi in situ. We measured soil CO2, T and θ at 5-min intervals into the soil profile. Using our automated minirhizotron (AMR) for hyphal dynamics and the Bartz minirhizotron for longer-term and spatial variation in roots and rhizomorphs, we measured root, rhizomorph, hyphal growth, and belowground phenology up to 4x daily. These data are coupled with sensors measuring eddy flux of water and CO2, sapflow for water fluxes and C fixation activity, and photographs for leaf phenology. Because our data were collected at short intervals, we can describe integrative C exchange using the DayCent model for NPP and measured NPP of rhizomorphs, and fungal hyphae. Here, we focused on an arbuscular mycorrhiza dominated meadow and an ectomycorrhizal pine/oak forest at the James Reserve, in southern California. By daily measuring hyphal growth and mortality, we constructed life-span estimates of mycorrhizal hyphae, and from these, C allocation estimates. In the meadow, the NPP was 141g/m2/y, with a productivity of fine root+internal AM fungi of 76.5g C/m2/y, and an estimated 10% of which is AM fungal C allocation (7.7 g/m2/y). Extramatrical AM hyphal peak standing crop was 10g/m2, with a lifespan of 46 days (with active hyphae persisting for ~240 days per year days). Thus, the annual AM fungal allocation was 7.7g C/m2/y internal and 52g/m2/y external, for a net allocation of 84g C/m2/y, or 60% of the estimated NPP. In the

  7. Remote sensing of temperate coniferous forest lead area index - The influence of canopy closure, understory vegetation and background reflectance

    Science.gov (United States)

    Spanner, Michael A.; Pierce, Lars L.; Running, Steven W.; Peterson, David L.

    1990-01-01

    Consideration is given to the effects of canopy closure, understory vegetation, and background reflectance on the relationship between Landsat TM data and the leaf area index (LAI) of temperate coniferous forests in the western U.S. A methodology for correcting TM data for atmospheric conditions and sun-surface-sensor geometry is discussed. Strong inverse curvilinear relationships were found between coniferous forest LAI and TM bands 3 and 5. It is suggested that these inverse relationships are due to increased reflectance of understory vegetation and background in open stands of lower LAI and decreased reflectance of the overstory in closed canopy stands with higher LAI.

  8. Patterns of plant diversity in seven temperate forest types of Western Himalaya, India

    Directory of Open Access Journals (Sweden)

    Javid Ahmad Dar

    2016-09-01

    Full Text Available Plant biodiversity patterns were analyzed in seven temperate forest types [Populus deltoides (PD, Juglans regia, Cedrus deodara, Pinus wallichiana, mixed coniferous, Abies pindrow (AP and Betula utilis (BU] of Kashmir Himalaya. A total of 177 plant species (158 genera, 66 families were recorded. Most of the species are herbs (82.5%, while shrubs account for 9.6% and trees represent 7.9%. Species richness ranged from 24 (PD to 96 (AP. Shannon, Simpson, and Fisher α indices varied: 0.17–1.06, 0.46–1.22, and 2.01–2.82 for trees; 0.36–0.94, 0.43–0.75, and 0.08–0.35 for shrubs; and 0.35–1.41, 0.27–0.95, and 5.61–39.98 for herbs, respectively. A total of five species were endemic. The total stems and basal area of trees were 35,794 stems (stand mean 330 stems/ha and 481.1 m2 (stand mean 40.2 m2/ha, respectively. The mean density and basal area ranged from 103 stems/ha (BU to 1,201 stems/ha (PD, and from 19.4 m2/ha (BU to 51.9 m2/ha (AP, respectively. Tree density decreased with increase in diameter class. A positive relationship was obtained between elevation and species richness and between elevation and evenness (R2 = 0.37 and 0.19, respectively. Tree and shrub communities were homogenous in nature across the seven forest types, while herbs showed heterogeneous distribution pattern.

  9. Abiotic and biotic control of methanol exchanges in a temperate mixed forest

    Directory of Open Access Journals (Sweden)

    Q. Laffineur

    2012-01-01

    Full Text Available Methanol exchanges over a mixed temperate forest in the Belgian Ardennes were measured for more than one vegetation season using disjunct eddy-covariance by a mass scanning technique and Proton Transfer Reaction Mass Spectrometry (PTR-MS. Half-hourly methanol fluxes were measured in the range of −0.6 μg m−2 s−1 to 0.6 μg m−2 s−1, and net daily methanol fluxes were generally negative in summer and autumn and positive in spring. On average, the negative fluxes dominated (i.e. the site behaved as a net sink, in contrast to what had been found in previous studies.

    An original model describing the adsorption/desorption of methanol in water films present in the forest ecosystem and the methanol degradation process was developed. Its calibration, based on field measurements, predicted a mean methanol degradation rate of −0.0074 μg m−2 s−1 and a half lifetime for methanol in water films of 57.4 h. Biogenic emissions dominated the exchange only in spring, with a standard emission factor of 0.76 μg m−2 s−1.

    The great ability of the model to reproduce the long-term evolution, as well as the diurnal variation of the fluxes, suggests that the adsorption/desorption and degradation processes play an important role in the global methanol budget. This result underlines the need to conduct long-term measurements in order to accurately capture these processes and to better estimate methanol fluxes at the ecosystem scale.

  10. Abiotic and biotic control of methanol exchanges in a temperate mixed forest

    Science.gov (United States)

    Laffineur, Q.; Aubinet, M.; Schoon, N.; Amelynck, C.; Müller, J.-F.; Dewulf, J.; van Langenhove, H.; Steppe, K.; Heinesch, B.

    2012-01-01

    Methanol exchanges over a mixed temperate forest in the Belgian Ardennes were measured for more than one vegetation season using disjunct eddy-covariance by a mass scanning technique and Proton Transfer Reaction Mass Spectrometry (PTR-MS). Half-hourly methanol fluxes were measured in the range of -0.6 μg m-2 s-1 to 0.6 μg m-2 s-1, and net daily methanol fluxes were generally negative in summer and autumn and positive in spring. On average, the negative fluxes dominated (i.e. the site behaved as a net sink), in contrast to what had been found in previous studies. An original model describing the adsorption/desorption of methanol in water films present in the forest ecosystem and the methanol degradation process was developed. Its calibration, based on field measurements, predicted a mean methanol degradation rate of -0.0074 μg m-2 s-1 and a half lifetime for methanol in water films of 57.4 h. Biogenic emissions dominated the exchange only in spring, with a standard emission factor of 0.76 μg m-2 s-1. The great ability of the model to reproduce the long-term evolution, as well as the diurnal variation of the fluxes, suggests that the adsorption/desorption and degradation processes play an important role in the global methanol budget. This result underlines the need to conduct long-term measurements in order to accurately capture these processes and to better estimate methanol fluxes at the ecosystem scale.

  11. Effects of density dependence in a temperate forest in northeastern China

    Science.gov (United States)

    Yao, Jie; Zhang, Xinna; Zhang, Chunyu; Zhao, Xiuhai; von Gadow, Klaus

    2016-09-01

    Negative density dependence may cause reduced clustering among individuals of the same species, and evidence is accumulating that conspecific density-dependent self-thinning is an important mechanism regulating the spatial structure of plant populations. This study evaluates that specific density dependence in three very large observational studies representing three successional stages in a temperate forest in northeastern China. The methods include standard spatial point pattern analysis and a heterogeneous Poisson process as the null model to eliminate the effects of habitat heterogeneity. The results show that most of the species exhibit conspecific density-dependent self-thinning. In the early successional stage 11 of the 16 species, in the intermediate successional stage 18 of the 21 species and in the old growth stage all 21 species exhibited density dependence after removing the effects of habitat heterogeneity. The prevalence of density dependence thus varies among the three successional stages and exhibits an increase with increasing successional stage. The proportion of species showing density dependence varied depending on whether habitat heterogeneity was removed or not. Furthermore, the strength of density dependence is closely related with species abundance. Abundant species with high conspecific aggregation tend to exhibit greater density dependence than rare species.

  12. Sergey gen. n., a new doryctine genus from temperate forests of Mexico and Cuba (Hymenoptera, Braconidae)

    Science.gov (United States)

    Martínez, Juan José; Lázaro, Rubi Nelsi Meza; Pedraza-Lara, Carlos; Zaldívar-Riverón, Alejandro

    2016-01-01

    Abstract The new doryctine genus Sergey gen. n. is described with four new species (Sergey cubaensis Zaldívar-Riverón & Martínez, sp. n., Sergey coahuilensis Zaldívar-Riverón & Martínez, sp. n., Sergey tzeltal Martínez & Zalídivar-Riverón, sp. n., Sergey tzotzil Martínez & Zalídivar-Riverón, sp. n.) from temperate forests of Mexico and Cuba. Similar to many other doryctine taxa, the new genus has a considerably elongated, petiolate basal sternal plate of the first metasomal tergite, although it can be distinguished from these by having the mesoscutum sharply declivous anteriorly with sharp anterolateral edges. The described species have been characterised molecularly based on two mitochondrial (COI, cyt b) and one nuclear (28S) gene markers. Based on the mitochondrial gene genealogies reconstructed, the evidence suggests the existence of incomplete lineage sorting or hybridization in the populations from Chiapas and Oaxaca assigned to Sergey tzeltal sp. n. PMID:27408539

  13. Fine-root mortality rates in a temperate forest: Estimates using radiocarbon data and numerical modeling

    Energy Technology Data Exchange (ETDEWEB)

    Riley, W.J.; Gaudinski, J.B.; Torn, M.S.; Joslin, J.D.; Hanson, P.J.

    2009-09-01

    We used an inadvertent whole-ecosystem {sup 14}C label at a temperate forest in Oak Ridge, Tennessee, USA to develop a model (Radix1.0) of fine-root dynamics. Radix simulates two live-root pools, two dead-root pools, non-normally distributed root mortality turnover times, a stored carbon (C) pool, and seasonal growth and respiration patterns. We applied Radix to analyze measurements from two root size classes (< 0.5 and 0.5-2.0 mm diameter) and three soil-depth increments (O horizon, 0-15 cm and 30-60 cm). Predicted live-root turnover times were < 1 yr and 10 yr for short- and long-lived pools, respectively. Dead-root pools had decomposition turnover times of 2 yr and 10 yr. Realistic characterization of C flows through fine roots requires a model with two live fine-root populations, two dead fine-root pools, and root respiration. These are the first fine-root turnover time estimates that take into account respiration, storage, seasonal growth patterns, and non-normal turnover time distributions. The presence of a root population with decadal turnover times implies a lower amount of belowground net primary production used to grow fine-root tissue than is currently predicted by models with a single annual turnover pool.

  14. Elevated CO₂ enhances leaf senescence during extreme drought in a temperate forest.

    Science.gov (United States)

    Warren, Jeffrey M; Norby, Richard J; Wullschleger, Stan D

    2011-02-01

    In 2007, an extreme drought and acute heat wave impacted ecosystems across the southeastern USA, including a 19-year-old Liquidambar styraciflua L. (sweetgum) tree plantation exposed to long-term elevated (E(CO(2))) or ambient (A(CO(2))) CO(2) treatments. Stem sap velocities were analyzed to assess plant response to potential interactions between CO(2) and these weather extremes. Canopy conductance and net carbon assimilation (A(net)) were modeled based on patterns of sap velocity to estimate indirect impacts of observed reductions in transpiration under E(CO(2)) on premature leaf senescence. Elevated CO(2) reduced sap flow by 28% during early summer, and by up to 45% late in the drought during record-setting temperatures. Modeled canopy conductance declined more rapidly in E(CO(2)) plots during this period, thereby directly reducing carbon gain at a greater rate than in A(CO(2)) plots. Indeed, pre-drought canopy A(net) was similar across treatment plots, but declined to ∼40% less than A(net) in A(CO(2)) as the drought progressed, likely leading to negative net carbon balance. Consequently, premature leaf senescence and abscission increased rapidly during this period, and was 30% greater for E(CO(2)). While E(CO(2)) can reduce leaf-level water use under droughty conditions, acute drought may induce excessive stomatal closure that could offset benefits of E(CO(2)) to temperate forest species during extreme weather events.

  15. Elevated CO2 enhances leaf senescence during extreme heat and drought in a temperate forest

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Jeffrey [ORNL; Norby, Richard J [ORNL; Wullschleger, Stan D [ORNL

    2011-01-01

    In 2007, an extreme drought and acute heat wave damaged ecosystems across the southeastern US, including a 19-year-old Liquidambar styraciflua L. (sweetgum) tree plantation exposed to long-term elevated CO2 treatments. Stem sap velocities in trees exposed to ambient (A) or elevated (E) CO2 were analyzed to assess potential interactions between CO2 and these weather extremes. Leaf temperature (Tleaf) and net carbon uptake (GPP) were modeled based on patterns of sap velocity to estimate indirect impacts of CO2-reduced transpiration on premature leaf senescence. Elevated CO2 reduced sap flow by 28% during early summer, and by up to 45% late in the drought during record-setting high air temperatures. Canopy transpiration and conductance declined more rapidly in ECO2 plots, resulting in ECO2 Tleaf up to 45 C, which was 1-2 C greater than ACO2 Tleaf. Pre-drought GPP was ~7% greater in ECO2 plots, then declined to 30% less than ACO2 GPP as the drought progressed. Leaf abscission peaked during this period, and was 30% greater for ECO2 trees. While ECO2 can reduce leaf-level water use under droughty conditions, acute drought or heat conditions may induce excessive stomatal closure that could offset benefits of ECO2 to temperate forest species during extreme weather events.

  16. Edge Effects on Community and Social Structure of Northern Temperate Deciduous Forest Ants

    Directory of Open Access Journals (Sweden)

    Valerie S. Banschbach

    2012-01-01

    Full Text Available Determining how ant communities are impacted by challenges from habitat fragmentation, such as edge effects, will help us understand how ants may be used as a bioindicator taxon. To assess the impacts of edge effects upon the ant community in a northern temperate deciduous forest, we studied edge and interior sites in Jericho, VT, USA. The edges we focused upon were created by recreational trails. We censused the ants at these sites for two consecutive growing seasons using pitfall traps and litter plot excavations. We also collected nests of the most common ant species at our study sites, Aphaenogaster rudis, for study of colony demography. Significantly greater total numbers of ants and ant nests were found in the edge sites compared to the interior sites but rarefaction analysis showed no significant difference in species richness. Aphaenogaster rudis was the numerically dominant ant in the habitats sampled but had a greater relative abundance in the interior sites than in the edge sites both in pitfall and litter plot data. Queen number of A. rudis significantly differed between the nests collected in the edge versus the interior sites. Habitat-dependent changes in social structure of ants represent another possible indicator of ecosystem health.

  17. Changes of Organic Carbon Quantity and Quality in Temperate Forest Soils

    Science.gov (United States)

    Kühnel, Anna; Satwika Lestari, Annisa; Schubert, Alfred; Wiesmeier, Martin; Spörlein, Peter; Schilling, Bernd; Kögel-Knabner, Ingrid

    2017-04-01

    Climate change will have profound impacts on organic matter stocks and thus on the functionality of soils. Soil organic carbon (SOC) content in soil is mainly regulated by the fluxes of organic matter which are highly associated with the aboveground and root litter production and their decompositions into CO2 by soil microorganism. The predicted rising temperatures in Bavaria might lead to an increased decomposition and release of soil carbon into the atmosphere, which would deteriorate a number of important soil functions. Here, we present an assessment of SOC stocks in three temperate forest sites over the last 30 years. Soil to a depth of 30 cm was analysed with density fractionation to evaluate SOC stocks and distribution in different pools. Additionally, tree-aboveground organic carbon (OC) stocks were measured to assess their influence on SOC. SOC stocks decreased between 1988 and 2004 and increased between 2004 and 2016. OC changes of litter + O layer and mineral soil differed. Highest changes of SOC occurred in the light fractions, followed by the mineral fractions. Tree-aboveground biomass, stand composition, and changing climate had an influence on SOC stocks. Precipitation change was correlated with the litter + O layer OC stocks. Further studies on the changes of each SOC fraction and the influence of other edaphic factors are needed to better understand the changes in SOC stocks and quality.

  18. Temporal-spatial segregation among hummingbirds foraging on honeydew in a temperate forest in Mexico

    Directory of Open Access Journals (Sweden)

    Carlos LARA, Vanessa MARTÍNEZ-GARCÍA, Raúl ORTIZ-PULIDO, Jessica BRAVO-CADENA, Salvador LORANCA, Alex CÓRDOBA-AGUILAR

    2011-02-01

    Full Text Available Spatial and temporal variation in interactions between hummingbirds and plants have often been examined, and hummingbirds and insects are known to indirectly interact in networks of nectar plants. In a highland temperate forest in Hidalgo, Mexico some oak trees were heavily infested by honeydew-producing insects (family Margarodidae, tribe Xylococcini, genus Strigmacoccus and the honeydew was consumed by hummingbirds. Here using survival analysis we investigate how the honeydew produced by dense populations of these margarodids is temporally and spatially partitioned by hummingbirds. We also measured the availability and quality of honeydew exudates, and then we recorded the time until a bird visited and used such resources. Four hummingbird species consumed this resource (Atthis eloisa, Hylocharis leucotis, Colibri thalassinus and Eugenes fulgens. Data from 294 hours of observation on seven focal trees suggested temporal and spatial segregation among visiting birds according to body size and territorial behavior during the most honeydew-limited time. Hummingbird species differed in the daily times they foraged, as well as in the location where honeydew-producing insects were visited on the trees. Temporal and spatial segregation among hummingbird species is interpreted as an adaptation to reduce the risk of aggressive encounters. This may facilitate multispecies coexistence and allow these birds to exploit honeydew more effectively [Current Zoology 57 (1: 56–62, 2011].

  19. Altitudinal variation in soil organic carbon stock in coniferous subtropical and broadleaf temperate forests in Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Kumar Munesh

    2009-08-01

    Full Text Available Abstract Background The Himalayan zones, with dense forest vegetation, cover a fifth part of India and store a third part of the country reserves of soil organic carbon (SOC. However, the details of altitudinal distribution of these carbon stocks, which are vulnerable to forest management and climate change impacts, are not well known. Results This article reports the results of measuring the stocks of SOC along altitudinal gradients. The study was carried out in the coniferous subtropical and broadleaf temperate forests of Garhwal Himalaya. The stocks of SOC were found to be decreasing with altitude: from 185.6 to 160.8 t C ha-1 and from 141.6 to 124.8 t C ha-1 in temperature (Quercus leucotrichophora and subtropical (Pinus roxburghii forests, respectively. Conclusion The results of this study lead to conclusion that the ability of soil to stabilize soil organic matter depends negatively on altitude and call for comprehensive theoretical explanation

  20. Long-term forest soil warming alters microbial communities in temperate forest soils.

    Science.gov (United States)

    DeAngelis, Kristen M; Pold, Grace; Topçuoğlu, Begüm D; van Diepen, Linda T A; Varney, Rebecca M; Blanchard, Jeffrey L; Melillo, Jerry; Frey, Serita D

    2015-01-01

    Soil microbes are major drivers of soil carbon cycling, yet we lack an understanding of how climate warming will affect microbial communities. Three ongoing field studies at the Harvard Forest Long-term Ecological Research (LTER) site (Petersham, MA) have warmed soils 5°C above ambient temperatures for 5, 8, and 20 years. We used this chronosequence to test the hypothesis that soil microbial communities have changed in response to chronic warming. Bacterial community composition was studied using Illumina sequencing of the 16S ribosomal RNA gene, and bacterial and fungal abundance were assessed using quantitative PCR. Only the 20-year warmed site exhibited significant change in bacterial community structure in the organic soil horizon, with no significant changes in the mineral soil. The dominant taxa, abundant at 0.1% or greater, represented 0.3% of the richness but nearly 50% of the observations (sequences). Individual members of the Actinobacteria, Alphaproteobacteria and Acidobacteria showed strong warming responses, with one Actinomycete decreasing from 4.5 to 1% relative abundance with warming. Ribosomal RNA copy number can obfuscate community profiles, but is also correlated with maximum growth rate or trophic strategy among bacteria. Ribosomal RNA copy number correction did not affect community profiles, but rRNA copy number was significantly decreased in warming plots compared to controls. Increased bacterial evenness, shifting beta diversity, decreased fungal abundance and increased abundance of bacteria with low rRNA operon copy number, including Alphaproteobacteria and Acidobacteria, together suggest that more or alternative niche space is being created over the course of long-term warming.

  1. Vegetation Indices for Mapping Canopy Foliar Nitrogen in a Mixed Temperate Forest

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    Zhihui Wang

    2016-06-01

    findings demonstrated the feasibility of using hyperspectral vegetation indices to estimate %N in a mixed temperate forest which may relate to the effect of the physical basis of nitrogen absorption features on canopy reflectance, or the biological links between nitrogen, chlorophyll, and canopy structure.

  2. Distinct responses of soil respiration to experimental litter manipulation in temperate woodland and tropical forest.

    Science.gov (United States)

    Bréchet, Laëtitia M; Lopez-Sangil, Luis; George, Charles; Birkett, Ali J; Baxendale, Catherine; Castro Trujillo, Biancolini; Sayer, Emma J

    2018-04-01

    Global change is affecting primary productivity in forests worldwide, and this, in turn, will alter long-term carbon (C) sequestration in wooded ecosystems. On one hand, increased primary productivity, for example, in response to elevated atmospheric carbon dioxide (CO 2 ), can result in greater inputs of organic matter to the soil, which could increase C sequestration belowground. On other hand, many of the interactions between plants and microorganisms that determine soil C dynamics are poorly characterized, and additional inputs of plant material, such as leaf litter, can result in the mineralization of soil organic matter, and the release of soil C as CO 2 during so-called "priming effects". Until now, very few studies made direct comparison of changes in soil C dynamics in response to altered plant inputs in different wooded ecosystems. We addressed this with a cross-continental study with litter removal and addition treatments in a temperate woodland (Wytham Woods) and lowland tropical forest (Gigante forest) to compare the consequences of increased litterfall on soil respiration in two distinct wooded ecosystems. Mean soil respiration was almost twice as high at Gigante (5.0 μmol CO 2  m -2  s -1 ) than at Wytham (2.7 μmol CO 2  m -2  s -1 ) but surprisingly, litter manipulation treatments had a greater and more immediate effect on soil respiration at Wytham. We measured a 30% increase in soil respiration in response to litter addition treatments at Wytham, compared to a 10% increase at Gigante. Importantly, despite higher soil respiration rates at Gigante, priming effects were stronger and more consistent at Wytham. Our results suggest that in situ priming effects in wooded ecosystems track seasonality in litterfall and soil respiration but the amount of soil C released by priming is not proportional to rates of soil respiration. Instead, priming effects may be promoted by larger inputs of organic matter combined with slower turnover rates.

  3. Data from camera surveys identifying co-occurrence and occupancy linkages between fishers (Pekania pennanti), rodent prey, mesocarnivores, and larger predators in mixed-conifer forests.

    Science.gov (United States)

    Sweitzer, Rick A; Furnas, Brett J

    2016-03-01

    These data provide additional information relevant to the frequency of fisher detections by camera traps, and single-season occupancy and local persistence of fishers in small patches of forest habitats detailed elsewhere, "Landscape Fuel Reduction, Forest Fire, and Biophysical Linkages to Local Habitat Use and Local Persistence of Fishers (Pekania pennanti) in Sierra Nevada Mixed-conifer Forests" [10]. The data provides insight on camera trap detections of 3 fisher predators (bobcat [Lynx rufus]). Coyote [Canis latrans], mountain lion [Puma concolor], 5 mesocarnivores in the same foraging guild as fishers (gray fox [Urocyon cinereoargenteus]) ringtail [Bassariscus astutus], marten [Martes americana], striped skunk [Mephitis mephitis] spotted skunk [Spilogale gracilis], and 5 Sciuridae rodents that fishers consume as prey (Douglas squirrel [Tamiasciurus douglasii]), gray squirrel [Sciurus griseus], northern flying squirrel [Glaucomys sabrinus], long-eared chipmunk [Neotamias quadrimaculatus], California ground squirrel [Spermophilus beecheyi]. We used these data to identify basic patterns of co-occurrence with fishers, and to evaluate the relative importance of presence of competing mesocarnivores, rodent prey, and predators for fisher occupancy of small, 1 km(2) grid cells of forest habitat.

  4. An unsupervised two-stage clustering approach for forest structure classification based on X-band InSAR data - A case study in complex temperate forest stands

    Science.gov (United States)

    Abdullahi, Sahra; Schardt, Mathias; Pretzsch, Hans

    2017-05-01

    Forest structure at stand level plays a key role for sustainable forest management, since the biodiversity, productivity, growth and stability of the forest can be positively influenced by managing its structural diversity. In contrast to field-based measurements, remote sensing techniques offer a cost-efficient opportunity to collect area-wide information about forest stand structure with high spatial and temporal resolution. Especially Interferometric Synthetic Aperture Radar (InSAR), which facilitates worldwide acquisition of 3d information independent from weather conditions and illumination, is convenient to capture forest stand structure. This study purposes an unsupervised two-stage clustering approach for forest structure classification based on height information derived from interferometric X-band SAR data which was performed in complex temperate forest stands of Traunstein forest (South Germany). In particular, a four dimensional input data set composed of first-order height statistics was non-linearly projected on a two-dimensional Self-Organizing Map, spatially ordered according to similarity (based on the Euclidean distance) in the first stage and classified using the k-means algorithm in the second stage. The study demonstrated that X-band InSAR data exhibits considerable capabilities for forest structure classification. Moreover, the unsupervised classification approach achieved meaningful and reasonable results by means of comparison to aerial imagery and LiDAR data.

  5. Fine root productivity and turnover of ectomycorrhizal and arbuscular mycorrhizaltree species in a temperate broad-leaved mixed forest

    Directory of Open Access Journals (Sweden)

    Petra Kubisch

    2016-08-01

    Full Text Available Advancing our understanding of tree fine root dynamics is of high importance for tree physiology and forest biogeochemistry. In temperate broad-leaved forests, ectomycorrhizal (EM and arbuscular mycorrhizal (AM tree species often are coexisting. It is not known whether EM and AM trees differ systematically in fine root dynamics and belowground resource foraging strategies. We measured fine root productivity (FRP and fine root turnover (and its inverse, root longevity of three EM and three AM broad-leaved tree species in a natural cool-temperate mixed forest using ingrowth cores and combined the productivity data with data on root biomass per root orders. FRP and root turnover were related to root morphological traits and aboveground productivity.FRP differed up to twofold among the six coexisting species with larger species differences in lower horizons than in the topsoil. Root turnover varied up to fivefold among the species with lowest values in Acer pseudoplatanus and highest in its congener A. platanoides. Variation in root turnover was larger within the two groups than between EM and AM species. We conclude that the main determinant of fine root productivity and turnover in this mixed forest is species identity, while the influence of mycorrhiza type seems to be less important.

  6. An instrument design and sample strategy for measuring soil respiration in the coastal temperate rain forest

    Science.gov (United States)

    Nay, S. M.; D'Amore, D. V.

    2009-12-01

    The coastal temperate rainforest (CTR) along the northwest coast of North America is a large and complex mosaic of forests and wetlands located on an undulating terrain ranging from sea level to thousands of meters in elevation. This biome stores a dynamic portion of the total carbon stock of North America. The fate of the terrestrial carbon stock is of concern due to the potential for mobilization and export of this store to both the atmosphere as carbon respiration flux and ocean as dissolved organic and inorganic carbon flux. Soil respiration is the largest export vector in the system and must be accurately measured to gain any comprehensive understanding of how carbon moves though this system. Suitable monitoring tools capable of measuring carbon fluxes at small spatial scales are essential for our understanding of carbon dynamics at larger spatial scales within this complex assemblage of ecosystems. We have adapted instrumentation and developed a sampling strategy for optimizing replication of soil respiration measurements to quantify differences among spatially complex landscape units of the CTR. We start with the design of the instrument to ease the technological, ergonomic and financial barriers that technicians encounter in monitoring the efflux of CO2 from the soil. Our sampling strategy optimizes the physical efforts of the field work and manages for the high variation of flux measurements encountered in this difficult environment of rough terrain, dense vegetation and wet climate. Our soil respirometer incorporates an infra-red gas analyzer (LiCor Inc. LI-820) and an 8300 cm3 soil respiration chamber; the device is durable, lightweight, easy to operate and can be built for under $5000 per unit. The modest unit price allows for a multiple unit fleet to be deployed and operated in an intensive field monitoring campaign. We use a large 346 cm2 collar to accommodate as much micro spatial variation as feasible and to facilitate repeated measures for tracking

  7. Natural disturbance impacts on ecosystem services and biodiversity in temperate and boreal forests.

    Science.gov (United States)

    Thom, Dominik; Seidl, Rupert

    2016-08-01

    In many parts of the world forest disturbance regimes have intensified recently, and future climatic changes are expected to amplify this development further in the coming decades. These changes are increasingly challenging the main objectives of forest ecosystem management, which are to provide ecosystem services sustainably to society and maintain the biological diversity of forests. Yet a comprehensive understanding of how disturbances affect these primary goals of ecosystem management is still lacking. We conducted a global literature review on the impact of three of the most important disturbance agents (fire, wind, and bark beetles) on 13 different ecosystem services and three indicators of biodiversity in forests of the boreal, cool- and warm-temperate biomes. Our objectives were to (i) synthesize the effect of natural disturbances on a wide range of possible objectives of forest management, and (ii) investigate standardized effect sizes of disturbance for selected indicators via a quantitative meta-analysis. We screened a total of 1958 disturbance studies published between 1981 and 2013, and reviewed 478 in detail. We first investigated the overall effect of disturbances on individual ecosystem services and indicators of biodiversity by means of independence tests, and subsequently examined the effect size of disturbances on indicators of carbon storage and biodiversity by means of regression analysis. Additionally, we investigated the effect of commonly used approaches of disturbance management, i.e. salvage logging and prescribed burning. We found that disturbance impacts on ecosystem services are generally negative, an effect that was supported for all categories of ecosystem services, i.e. supporting, provisioning, regulating, and cultural services (P biodiversity, i.e. species richness, habitat quality and diversity indices, on the other hand were found to be influenced positively by disturbance (P biodiversity. A detailed investigation of disturbance

  8. Drought enhances symbiotic dinitrogen fixation and competitive ability of a temperate forest tree.

    Science.gov (United States)

    Wurzburger, Nina; Miniat, Chelcy Ford

    2014-04-01

    General circulation models project more intense and frequent droughts over the next century, but many questions remain about how terrestrial ecosystems will respond. Of particular importance, is to understand how drought will alter the species composition of regenerating temperate forests wherein symbiotic dinitrogen (N2)-fixing plants play a critical role. In experimental mesocosms we manipulated soil moisture to study the effect of drought on the physiology, growth and competitive interactions of four co-occurring North American tree species, one of which (Robinia pseudoacacia) is a symbiotic N2-fixer. We hypothesized that drought would reduce growth by decreasing stomatal conductance, hydraulic conductance and increasing the water use efficiency of species with larger diameter xylem vessel elements (Quercus rubra, R. pseudoacacia) relative to those with smaller elements (Acer rubrum and Liriodendron tulipifera). We further hypothesized that N2 fixation by R. pseudoacacia would decline with drought, reducing its competitive ability. Under drought, growth declined across all species; but, growth and physiological responses did not correspond to species' hydraulic architecture. Drought triggered an 80% increase in nodule biomass and N accrual for R. pseudoacacia, improving its growth relative to other species. These results suggest that drought intensified soil N deficiency and that R. pseudoacacia's ability to fix N2 facilitated competition with non-fixing species when both water and N were limiting. Under scenarios of moderate drought, N2 fixation may alleviate the N constraints resulting from low soil moisture and improve competitive ability of N2-fixing species, and as a result, supply more new N to the ecosystem.

  9. The effect of prescribed burning on plant rarity in a temperate forest.

    Science.gov (United States)

    Patykowski, John; Holland, Greg J; Dell, Matt; Wevill, Tricia; Callister, Kate; Bennett, Andrew F; Gibson, Maria

    2018-02-01

    Rare species can play important functional roles, but human-induced changes to disturbance regimes, such as fire, can inadvertently affect these species. We examined the influence of prescribed burns on the recruitment and diversity of plant species within a temperate forest in southeastern Australia, with a focus on species that were rare prior to burning. Floristic composition was compared among plots in landscapes before and after treatment with prescribed burns differing in the extent of area burnt and season of burn (before-after, control-impact design). Floristic surveys were conducted before burns, at the end of a decade of drought, and 3 years postburn. We quantified the effect of prescribed burns on species grouped by their frequency within the landscape before burning (common, less common, and rare) and their life-form attributes (woody perennials, perennial herbs or geophytes, and annual herbs). Burn treatment influenced the response of rare species. In spring-burn plots, the recruitment of rare annual herbs was promoted, differentiating this treatment from both autumn-burn and unburnt plots. In autumn-burn plots, richness of rare species increased across all life-form groups, although composition remained statistically similar to control plots. Richness of rare woody perennials increased in control plots. For all other life-form and frequency groups, the floristic composition of landscapes changed between survey years, but there was no effect of burn treatment, suggesting a likely effect of rainfall on species recruitment. A prescribed burn can increase the occurrence of rare species in a landscape, but burn characteristics can affect the promotion of different life-form groups and thus affect functional diversity. Drought-breaking rain likely had an overarching effect on floristic composition during our study, highlighting that weather can play a greater role in influencing recruitment and diversity in plant communities than a prescribed burn.

  10. Seasonal variation in the temperature sensitivity of proteolytic enzyme activity in temperate forest soils

    Science.gov (United States)

    Brzostek, Edward R.; Finzi, Adrien C.

    2012-03-01

    Increasing soil temperature has the potential to alter the activity of the extracellular enzymes that mobilize nitrogen (N) from soil organic matter (SOM) and ultimately the availability of N for primary production. Proteolytic enzymes depolymerize N from proteinaceous components of SOM into amino acids, and their activity is a principal driver of the within-system cycle of soil N. The objectives of this study were to investigate whether the soils of temperate forest tree species differ in the temperature sensitivity of proteolytic enzyme activity over the growing season and the role of substrate limitation in regulating temperature sensitivity. Across species and sampling dates, proteolytic enzyme activity had relatively low sensitivity to temperature with a mean activation energy (Ea) of 33.5 kJ mol-1. Ea declined in white ash, American beech, and eastern hemlock soils across the growing season as soils warmed. By contrast, Eain sugar maple soil increased across the growing season. We used these data to develop a species-specific empirical model of proteolytic enzyme activity for the 2009 calendar year and studied the interactive effects of soil temperature (ambient or +5°C) and substrate limitation (ambient or elevated protein) on enzyme activity. Declines in substrate limitation had a larger single-factor effect on proteolytic enzyme activity than temperature, particularly in the spring. There was, however, a large synergistic effect of increasing temperature and substrate supply on proteolytic enzyme activity. Our results suggest limited increases in N availability with climate warming unless there is a parallel increase in the availability of protein substrates.

  11. Chlorophyll fluorescence tracks seasonal variations of photosynthesis from leaf to canopy in a temperate forest.

    Science.gov (United States)

    Yang, Hualei; Yang, Xi; Zhang, Yongguang; Heskel, Mary A; Lu, Xiaoliang; Munger, J William; Sun, Shucun; Tang, Jianwu

    2017-07-01

    Accurate estimation of terrestrial gross primary productivity (GPP) remains a challenge despite its importance in the global carbon cycle. Chlorophyll fluorescence (ChlF) has been recently adopted to understand photosynthesis and its response to the environment, particularly with remote sensing data. However, it remains unclear how ChlF and photosynthesis are linked at different spatial scales across the growing season. We examined seasonal relationships between ChlF and photosynthesis at the leaf, canopy, and ecosystem scales and explored how leaf-level ChlF was linked with canopy-scale solar-induced chlorophyll fluorescence (SIF) in a temperate deciduous forest at Harvard Forest, Massachusetts, USA. Our results show that ChlF captured the seasonal variations of photosynthesis with significant linear relationships between ChlF and photosynthesis across the growing season over different spatial scales (R 2  = 0.73, 0.77, and 0.86 at leaf, canopy, and satellite scales, respectively; P < 0.0001). We developed a model to estimate GPP from the tower-based measurement of SIF and leaf-level ChlF parameters. The estimation of GPP from this model agreed well with flux tower observations of GPP (R 2  = 0.68; P < 0.0001), demonstrating the potential of SIF for modeling GPP. At the leaf scale, we found that leaf F q '/F m ', the fraction of absorbed photons that are used for photochemistry for a light-adapted measurement from a pulse amplitude modulation fluorometer, was the best leaf fluorescence parameter to correlate with canopy SIF yield (SIF/APAR, R 2  = 0.79; P < 0.0001). We also found that canopy SIF and SIF-derived GPP (GPP SIF ) were strongly correlated to leaf-level biochemistry and canopy structure, including chlorophyll content (R 2  = 0.65 for canopy GPP SIF and chlorophyll content; P < 0.0001), leaf area index (LAI) (R 2  = 0.35 for canopy GPP SIF and LAI; P < 0.0001), and normalized difference vegetation index (NDVI) (R 2  = 0.36 for

  12. Continuous measurements of methane flux in two Japanese temperate forests based on the micrometeorological and chamber methods

    Science.gov (United States)

    Yoshikawa, K.; Ueyama, M.; Takagi, K.; Kominami, Y.

    2015-12-01

    Methane (CH4) budget in forest ecosystems have not been accurately quantified due to limited measurements and considerable spatiotemporal heterogeneity. In order to quantify CH4 fluxes at temperate forest at various spatiotemporal scales, we have continuously measured CH4 fluxes at two upland forests based on the micrometeorological hyperbolic relaxed eddy accumulation (HREA) and automated dynamic closed chamber methods.The measurements have been conducted at Teshio experimental forest (TSE) since September 2013 and Yamashiro forest meteorology research site (YMS) since November 2014. Three automated chambers were installed on each site. Our system can measure CH4 flux by the micrometeorological HREA, vertical concentration profile at four heights, and chamber measurements by a laser-based gas analyzer (FGGA-24r-EP, Los Gatos Research Inc., USA).Seasonal variations of canopy-scale CH4 fluxes were different in each site. CH4 was consumed during the summer, but was emitted during the fall and winter in TSE; consequently, the site acted as a net annual CH4 source. CH4 was steadily consumed during the winter, but CH4 fluxes fluctuated between absorption and emission during the spring and summer in YMS. YMS acted as a net annual CH4 sink. CH4 uptake at the canopy scale generally decreased with rising soil temperature and increased with drying condition for both sites. CH4 flux measured by most of chambers showed the consistent sensitivity examined for the canopy scale to the environmental variables. CH4 fluxes from a few chambers located at a wet condition were independent of variations in soil temperature and moisture at both sites. Magnitude of soil CH4 uptake was higher than the canopy-scale CH4 uptake. Our results showed that the canopy-scale CH4 fluxes were totally different with the plot-scale CH4 fluxes by chambers, suggesting the considerable spatial heterogeneity in CH4 flux at the temperate forests.

  13. Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

    Science.gov (United States)

    2012-01-01

    Background Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and industrial forest carbon cycles are rarely studied in a whole-system structure. The forest system carbon balance is the difference between the biological (net ecosystem production) and industrial (net emissions from forest industry) forest carbon cycles, but to date this critical whole system analysis is lacking. This study presents a model of the forest system, uses it to compute the carbon balance, and outlines a methodology to maximize future carbon uptake in a managed forest region. Results We used a coupled forest ecosystem process and forest products life cycle inventory model for a regional temperate forest in the Midwestern U.S., and found the net system carbon balance for this 615,000 ha forest was positive (2.29 t C ha-1 yr-1). The industrial carbon budget was typically less than 10% of the biological system annually, and averaged averaged 0.082 t C ha-1 yr-1. Net C uptake over the next 100-years increased by 22% or 0.33 t C ha-1 yr-1 relative to the current harvest rate in the study region under the optized harvest regime. Conclusions The forest’s biological ecosystem current and future carbon uptake capacity is largely determined by forest harvest practices that occurred over a century ago, but we show an optimized harvesting strategy would increase future carbon sequestration, or wood production, by 20-30%, reduce long transportation chain emissions, and maintain many desirable stand structural attributes that are correlated to biodiversity. Our results for this forest region suggest that increasing harvest over the next 100 years increases the strength of

  14. Estimating the carbon budget and maximizing future carbon uptake for a temperate forest region in the U.S.

    Directory of Open Access Journals (Sweden)

    Peckham Scott D

    2012-06-01

    Full Text Available Abstract Background Forests of the Midwest U.S. provide numerous ecosystem services. Two of these, carbon sequestration and wood production, are often portrayed as conflicting. Currently, carbon management and biofuel policies are being developed to reduce atmospheric CO2 and national dependence on foreign oil, and increase carbon storage in ecosystems. However, the biological and industrial forest carbon cycles are rarely studied in a whole-system structure. The forest system carbon balance is the difference between the biological (net ecosystem production and industrial (net emissions from forest industry forest carbon cycles, but to date this critical whole system analysis is lacking. This study presents a model of the forest system, uses it to compute the carbon balance, and outlines a methodology to maximize future carbon uptake in a managed forest region. Results We used a coupled forest ecosystem process and forest products life cycle inventory model for a regional temperate forest in the Midwestern U.S., and found the net system carbon balance for this 615,000 ha forest was positive (2.29 t C ha-1 yr-1. The industrial carbon budget was typically less than 10% of the biological system annually, and averaged averaged 0.082 t C ha-1 yr-1. Net C uptake over the next 100-years increased by 22% or 0.33 t C ha-1 yr-1 relative to the current harvest rate in the study region under the optized harvest regime. Conclusions The forest’s biological ecosystem current and future carbon uptake capacity is largely determined by forest harvest practices that occurred over a century ago, but we show an optimized harvesting strategy would increase future carbon sequestration, or wood production, by 20-30%, reduce long transportation chain emissions, and maintain many desirable stand structural attributes that are correlated to biodiversity. Our results for this forest region suggest that increasing harvest over the next 100

  15. Effects of simulated acid rain on soil respiration and its components in a subtropical mixed conifer and broadleaf forest in southern China.

    Science.gov (United States)

    Liang, Guohua; Hui, Dafeng; Wu, Xiaoying; Wu, Jianping; Liu, Juxiu; Zhou, Guoyi; Zhang, Deqiang

    2016-02-01

    Soil respiration is a major pathway in the global carbon cycle and its response to environmental changes is an increasing concern. Here we explored how total soil respiration (RT) and its components respond to elevated acid rain in a mixed conifer and broadleaf forest, one of the major forest types in southern China. RT was measured twice a month in the first year under four treatment levels of simulated acid rain (SAR: CK, the local lake water, pH 4.7; T1, water pH 4.0; T2, water pH 3.25; and T3, water pH 2.5), and in the second year, RT, litter-free soil respiration (RS), and litter respiration (RL) were measured simultaneously. The results indicated that the mean rate of RT was 2.84 ± 0.20 μmol CO2 m(-2) s(-1) in the CK plots, and RS and RL contributed 60.7% and 39.3% to RT, respectively. SAR marginally reduced (P = 0.08) RT in the first year, but significantly reduced RT and its two components in the second year (P acid rain, the decline trend of RT in the forests in southern China appears to be attributable to the decline of soil respiration in the litter layer.

  16. Canopy uptake of atmospheric N deposition at a conifer forest: part I -canopy N budget, photosynthetic efficiency and net ecosystem exchange

    International Nuclear Information System (INIS)

    Sievering, H.; Tomaszewski, T.; Torizzo, J.

    2007-01-01

    Global carbon cycle assessments of anthropogenic nitrogen (N) deposition influences on carbon sequestration often assume enhanced sequestration results. This assumption was evaluated at a Rocky Mountains spruce-fir forest. Forest canopy N uptake (CNU) of atmospheric N deposition was estimated by combining event wet and throughfall N fluxes with gradient measured HNO 3 and NH 3 as well as inferred (NO x and particulate N) dry fluxes. Approximately 80% of the growing-season 3 kg N/ha total deposition is retained in canopy foliage and branches. This CNU constitutes ∼1/3 of canopy growing season new N supply at this conifer forest site. Daytime net ecosystem exchange (NEE) significantly (P = 0.006) and negatively (CO 2 uptake) correlated with CNU. Multiple regression indicates ∼20% of daytime NEE may be attributed to CNU (P < 0.02); more than soil water content. A wet deposition N-amendment study (Tomaszewski and Sievering), at canopy spruce branches, increased their growing-season CNU by 40-50% above ambient. Fluorometry and gas exchange results show N-amended spruce branches had greater photosynthetic efficiency and higher carboxylation rates than control and untreated branches. N-amended branches had 25% less photoinhibition, with a 5-9% greater proportion of foliar-N-in-Rubisco. The combined results provide, partly, a mechanistic explanation for the NEE dependence on CNU

  17. Data from camera surveys identifying co-occurrence and occupancy linkages between fishers (Pekania pennanti, rodent prey, mesocarnivores, and larger predators in mixed-conifer forests

    Directory of Open Access Journals (Sweden)

    Rick A. Sweitzer

    2016-03-01

    Full Text Available These data provide additional information relevant to the frequency of fisher detections by camera traps, and single-season occupancy and local persistence of fishers in small patches of forest habitats detailed elsewhere, “Landscape Fuel Reduction, Forest Fire, and Biophysical Linkages to Local Habitat Use and Local Persistence of Fishers (Pekania pennanti in Sierra Nevada Mixed-conifer Forests” [10]. The data provides insight on camera trap detections of 3 fisher predators (bobcat [Lynx rufus]. Coyote [Canis latrans], mountain lion [Puma concolor], 5 mesocarnivores in the same foraging guild as fishers (gray fox [Urocyon cinereoargenteus] ringtail [Bassariscus astutus], marten [Martes americana], striped skunk [Mephitis mephitis] spotted skunk [Spilogale gracilis], and 5 Sciuridae rodents that fishers consume as prey (Douglas squirrel [Tamiasciurus douglasii], gray squirrel [Sciurus griseus], northern flying squirrel [Glaucomys sabrinus], long-eared chipmunk [Neotamias quadrimaculatus], California ground squirrel [Spermophilus beecheyi]. We used these data to identify basic patterns of co-occurrence with fishers, and to evaluate the relative importance of presence of competing mesocarnivores, rodent prey, and predators for fisher occupancy of small, 1 km2 grid cells of forest habitat.

  18. Long-term effects of prescribed fire on mixed conifer forest structure in the Sierra Nevada, California

    Science.gov (United States)

    Phillip J. Van Mantgem; Nathan L. Stephenson; Eric Knapp; John Barrles; Jon E. Keeley

    2011-01-01

    The capacity of prescribed fire to restore forest conditions is often judged by changes in forest structure within a few years following burning. However, prescribed fire might have longer-term effects on forest structure, potentially changing treatment assessments. We examined annual changes in forest structure in five 1 ha old-growth plots immediately before...

  19. Combined Use of Airborne Lidar and DBInSAR Data to Estimate LAI in Temperate Mixed Forests

    Science.gov (United States)

    Peduzzi, Alicia; Wynne, Randolph Hamilton; Thomas, Valerie A.; Nelson, Ross F.; Reis, James J.; Sanford, Mark

    2012-01-01

    The objective of this study was to determine whether leaf area index (LAI) in temperate mixed forests is best estimated using multiple-return airborne laser scanning (lidar) data or dual-band, single-pass interferometric synthetic aperture radar data (from GeoSAR) alone, or both in combination. In situ measurements of LAI were made using the LiCor LAI-2000 Plant Canopy Analyzer on 61 plots (21 hardwood, 36 pine, 4 mixed pine hardwood; stand age ranging from 12-164 years; mean height ranging from 0.4 to 41.2 m) in the Appomattox-Buckingham State Forest, Virginia, USA. Lidar distributional metrics were calculated for all returns and for ten one meter deep crown density slices (a new metric), five above and five below the mode of the vegetation returns for each plot. GeoSAR metrics were calculated from the X-band backscatter coefficients (four looks) as well as both X- and P-band interferometric heights and magnitudes for each plot. Lidar metrics alone explained 69% of the variability in LAI, while GeoSAR metrics alone explained 52%. However, combining the lidar and GeoSAR metrics increased the R2 to 0.77 with a CV-RMSE of 0.42. This study indicates the clear potential for X-band backscatter and interferometric height (both now available from spaceborne sensors), when combined with small-footprint lidar data, to improve LAI estimation in temperate mixed forests.

  20. Emissions of trace gases from Australian temperate forest fires: emission factors and dependence on modified combustion efficiency

    Science.gov (United States)

    Guérette, Elise-Andrée; Paton-Walsh, Clare; Desservettaz, Maximilien; Smith, Thomas E. L.; Volkova, Liubov; Weston, Christopher J.; Meyer, Carl P.

    2018-03-01

    We characterised trace gas emissions from Australian temperate forest fires through a mixture of open-path Fourier transform infrared (OP-FTIR) measurements and selective ion flow tube mass spectrometry (SIFT-MS) and White cell FTIR analysis of grab samples. We report emission factors for a total of 25 trace gas species measured in smoke from nine prescribed fires. We find significant dependence on modified combustion efficiency (MCE) for some species, although regional differences indicate that the use of MCE as a proxy may be limited. We also find that the fire-integrated MCE values derived from our in situ on-the-ground open-path measurements are not significantly different from those reported for airborne measurements of smoke from fires in the same ecosystem. We then compare our average emission factors to those measured for temperate forest fires elsewhere (North America) and for fires in another dominant Australian ecosystem (savanna) and find significant differences in both cases. Indeed, we find that although the emission factors of some species agree within 20 %, including those of hydrogen cyanide, ethene, methanol, formaldehyde and 1,3-butadiene, others, such as acetic acid, ethanol, monoterpenes, ammonia, acetonitrile and pyrrole, differ by a factor of 2 or more. This indicates that the use of ecosystem-specific emission factors is warranted for applications involving emissions from Australian forest fires.

  1. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Science.gov (United States)

    He, Yujie; Yang, Jinyan; Zhuang, Qianlai; Harden, Jennifer W.; McGuire, A. David; Liu, Yaling; Wang, Gangsheng; Gu, Lianhong

    2015-01-01

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = −0.43 to −0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  2. Tree Death Not Resulting in Gap Creation: An Investigation of Canopy Dynamics of Northern Temperate Deciduous Forests

    Directory of Open Access Journals (Sweden)

    Jean-Francois Senécal

    2018-01-01

    Full Text Available Several decades of research have shown that canopy gaps drive tree renewal processes in the temperate deciduous forest biome. In the literature, canopy gaps are usually defined as canopy openings that are created by partial or total tree death of one or more canopy trees. In this study, we investigate linkages between tree damage mechanisms and the formation or not of new canopy gaps in northern temperate deciduous forests. We studied height loss processes in unmanaged and managed forests recovering from partial cutting with multi-temporal airborne Lidar data. The Lidar dataset was used to detect areas where canopy height reduction occurred, which were then field-studied to identify the tree damage mechanisms implicated. We also sampled the density of leaf material along transects to characterize canopy structure. We used the dataset of the canopy height reduction areas in a multi-model inference analysis to determine whether canopy structures or tree damage mechanisms most influenced the creation of new canopy gaps within canopy height reduction areas. According to our model, new canopy gaps are created mainly when canopy damage enlarges existing gaps or when height is reduced over areas without an already established dense sub-canopy tree layer.

  3. The effects of gap size on some microclimate variables during late summer and autumn in a temperate broadleaved deciduous forest.

    Science.gov (United States)

    Abd Latif, Zulkiflee; Blackburn, George Alan

    2010-03-01

    The creation of gaps can strongly influence forest regeneration and habitat diversity within forest ecosystems. However, the precise characteristics of such effects depend, to a large extent, upon the way in which gaps modify microclimate and soil water content. Hence, the aim of this study was to understand the effects of gap creation and variations in gap size on forest microclimate and soil water content. The study site, in North West England, was a mixed temperate broadleaved deciduous forest dominated by mature sessile oak (Quercus petraea), beech (Fagus sylvatica) and ash (Fraxinus excelsior) with some representatives of sycamore (Acer pseudoplatanus). Solar radiation (I), air temperature (T(A)), soil temperature (T(S)), relative humidity (h), wind speed (v) and soil water content (Psi) were measured at four natural treefall gaps created after a severe storm in 2006 and adjacent sub-canopy sites. I, T(A), T(S), and Psi increased significantly with gap size; h was consistently lower in gaps than the sub-canopy but did not vary with gap size, while the variability of v could not be explained by the presence or size of gaps. There were systematic diurnal patterns in all microclimate variables in response to gaps, but no such patterns existed for Psi. These results further our understanding of the abiotic and consequent biotic responses to gaps in broadleaved deciduous forests created by natural treefalls, and provide a useful basis for evaluating the implications of forest management practices.

  4. Wood ant nests as hot spots of carbon dioxide production and cold spots of methane oxidation in temperate forests

    Science.gov (United States)

    Jilkova, Veronika; Picek, Tomas; Cajthaml, Tomas; Frouz, Jan

    2016-04-01

    Wood ant nests are known as hot spots of carbon dioxide (CO2) production and are also thought to affect methane (CH4) flux. Stable high temperatures are maintained in ant nests even in cold environments. Here we focused on quantification of CO2 and CH4 flux in wood ant nests, contribution of ants and microbes to CO2 production, properties of nest material that affect CO2 production and the role of ants and microbes in the maintenance of nest temperature. The research was conducted in temperate and boreal forests inhabited by wood ants (Formica s. str.). Gas fluxes were measured either by an infrared gas analyser or a static chamber technique. Ants and nest materials were also incubated in a laboratory. Material properties potentially influencing CO2 flux, such as moisture, nutrient content or temperature were determined. According to the results, CH4 oxidation was lower in wood ant nests than in the surrounding forest soil suggesting that some characteristics of ant nests hinder CH4 oxidation or promote CH4 production. These characteristics were mainly available carbon and nitrogen contents. Wood ant nests clearly are hot spots of CO2 production in temperate forests originating mainly from ant and also from microbial metabolism. Most important properties positively affecting CO2 production were found to be moisture, nutrient content and temperature. Nest temperature is maintained by ant and microbial metabolism; nests from colder environments produce more metabolic heat to maintain similar temperature as nests from warmer environments. In conclusion, as the abundance of wood ant nests in some forests can be very high, ant nests may largely increase heterogeneity in greenhouse gas fluxes in forest ecosystems.

  5. Mechanisms Driving Galling Success in a Fragmented Landscape: Synergy of Habitat and Top-Down Factors along Temperate Forest Edges.

    Directory of Open Access Journals (Sweden)

    Nina-S Kelch

    Full Text Available Edge effects play key roles in the anthropogenic transformation of forested ecosystems and their biota, and are therefore a prime field of contemporary fragmentation research. We present the first empirical study to address edge effects on the population level of a widespread galling herbivore in a temperate deciduous forest. By analyzing edge effects on abundance and trophic interactions of beech gall midge (Mikiola fagi Htg., we found 30% higher gall abundance in the edge habitat as well as lower mortality rates due to decreased top-down control, especially by parasitoids. Two GLM models with similar explanatory power (58% identified habitat specific traits (such as canopy closure and altitude and parasitism as the best predictors of gall abundance. Further analyses revealed a crucial influence of light exposure (46% on top-down control by the parasitoid complex. Guided by a conceptual framework synthesizing the key factors driving gall density, we conclude that forest edge proliferation of M. fagi is due to a complex interplay of abiotic changes and trophic control mechanisms. Most prominently, it is caused by the microclimatic regime in forest edges, acting alone or in synergistic concert with top-down pressure by parasitoids. Contrary to the prevailing notion that specialists are edge-sensitive, this turns M. fagi into a winner species in fragmented temperate beech forests. In view of the increasing proportion of edge habitats and the documented benefits from edge microclimate, we call for investigations exploring the pest status of this galling insect and the modulators of its biological control.

  6. Spatial variability in tree stem CH4 fluxes suggests that uptake dominates over emission across temperate and tropical upland forests.

    Science.gov (United States)

    Gauci, Vincent; Welch, Bertie; Pangala, Sunitha; Sayer, Emma; Enrich-Prast, Alex; Bastviken, David

    2017-04-01

    Forests play an important role in the exchange of radiatively important gases with the atmosphere. Previous studies have shown that in both temperate and tropical wetland forests tree stems are significant sources of methane (CH4), yet little is known about trace greenhouse gas dynamics in 'upland' free-draining soils that dominate global forested areas. We examined trace gas (CH4 and N2O) fluxes from both soils and tree stems in lowland tropical forest on free-draining soils in Panama, Central America (Barro Colorado Nature Monument), in the Amazon (Cunia) and from a deciduous woodland in the United Kingdom (Wytham, Oxfordshire). In Panama, fluxes were sampled over the dry to wet season transition (March-August) in 2014 and November 2015. In Cunia, we measured mature and young tree fluxes in a single campaign during 2013 from two 20 x 30 m plots. CH4 and N2O flux was measured from the stem between 20 and 140 cm above the forest floor. Soil fluxes were measured 1 m away from each tree under investigation. Temperate fluxes were sampled at Wytham Woods, Oxfordshire, over 12 months from February 2015 to January 2016. Tree stem samples were collected via syringe from temporary chambers strapped to the trees and soil fluxes were sampled from installed collars. We found that trees behaved as both sources (near the tree base) and sinks (higher up the tree stem) of methane across Panamanian and UK sites, however, this pattern was only apparent in a subset of trees in the Amazon where the dominant process was stem CH4 uptake for the majority of trees. We synthesise these results and those of our N2O measurements and report the consequences for ecosystem budgets of these gases.

  7. Water use by a warm-temperate deciduous forest under the influence of the Asian monsoon: contributions of the overstory and understory to forest water use.

    Science.gov (United States)

    Jung, Eun-Young; Otieno, Dennis; Kwon, Hyojung; Lee, Bora; Lim, Jong-Hwan; Kim, Joon; Tenhunen, John

    2013-09-01

    The warm temperate deciduous forests in Asia have a relatively dense understory, hence, it is imperative that we understand the dynamics of transpiration in both the overstory (E O) and understory (E U) of forest stands under the influence of the Asian monsoon in order to improve the accuracy of forest water use budgeting and to identify key factors controlling forest water use under climate change. In this study, E O and E U of a temperate deciduous forest stand located in South Korea were measured during the growing season of 2008 using sap flow methods. The objectives of this study were (1) to quantify the total transpiration of the forest stand, i.e., overstory and understory, (2) to determine their relative contribution to ecosystem evapotranspiration (E eco), and (3) to identify factors controlling the transpiration of each layer. E O and E U were 174 and 22 mm, respectively. Total transpiration accounted for 55 % of the total E eco, revealing the importance of unaccounted contributions to E eco (i.e., soil evaporation and wet canopy evaporation). During the monsoon period, there was a strong reduction in the total transpiration, likely because of reductions in photosynthetic active radiation, vapor pressure deficit and plant area index. The ratio of E U to E O declined during the same period, indicating an effect of monsoon on the partitioning of E eco in its two components. The seasonal pattern of E O was synchronized with the overstory canopy development, which equally had a strong regulatory influence on E U.

  8. Elevated carbon dioxide and ozone alter productivity and ecosystem carbon content in northern temperate forests

    Science.gov (United States)

    Talhelm, Alan F; Pregitzer, Kurt S; Kubiske, Mark E; Zak, Donald R; Campany, Courtney E; Burton, Andrew J; Dickson, Richard E; Hendrey, George R; Isebrands, J G; Lewin, Keith F; Nagy, John; Karnosky, David F

    2014-01-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and tropospheric ozone (O3) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3. Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r2 = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m−2) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (ΔNPP/ΔN) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2. Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. PMID:24604779

  9. Long-Term Warming Alters Carbohydrate Degradation Potential in Temperate Forest Soils.

    Science.gov (United States)

    Pold, Grace; Billings, Andrew F; Blanchard, Jeff L; Burkhardt, Daniel B; Frey, Serita D; Melillo, Jerry M; Schnabel, Julia; van Diepen, Linda T A; DeAngelis, Kristen M

    2016-11-15

    As Earth's climate warms, soil carbon pools and the microbial communities that process them may change, altering the way in which carbon is recycled in soil. In this study, we used a combination of metagenomics and bacterial cultivation to evaluate the hypothesis that experimentally raising soil temperatures by 5°C for 5, 8, or 20 years increased the potential for temperate forest soil microbial communities to degrade carbohydrates. Warming decreased the proportion of carbohydrate-degrading genes in the organic horizon derived from eukaryotes and increased the fraction of genes in the mineral soil associated with Actinobacteria in all studies. Genes associated with carbohydrate degradation increased in the organic horizon after 5 years of warming but had decreased in the organic horizon after warming the soil continuously for 20 years. However, a greater proportion of the 295 bacteria from 6 phyla (10 classes, 14 orders, and 34 families) isolated from heated plots in the 20-year experiment were able to depolymerize cellulose and xylan than bacterial isolates from control soils. Together, these findings indicate that the enrichment of bacteria capable of degrading carbohydrates could be important for accelerated carbon cycling in a warmer world. The massive carbon stocks currently held in soils have been built up over millennia, and while numerous lines of evidence indicate that climate change will accelerate the processing of this carbon, it is unclear whether the genetic repertoire of the microbes responsible for this elevated activity will also change. In this study, we showed that bacteria isolated from plots subject to 20 years of 5°C of warming were more likely to depolymerize the plant polymers xylan and cellulose, but that carbohydrate degradation capacity is not uniformly enriched by warming treatment in the metagenomes of soil microbial communities. This study illustrates the utility of combining culture-dependent and culture-independent surveys of

  10. Collaborative Research: Snow Accumulation and Snow Melt in a Mixed Northern Hardwood-Conifer Forest, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains snow depth, Snow Water Equivalent (SWE), and forest cover characteristics for sites at the Hubbard Brook Experimental Forest in northern New...

  11. Combustion efficiency and emission factors for wildfire-season fires in mixed conifer forests of the northern Rocky Mountains, US

    Science.gov (United States)

    S. P. Urbanski

    2013-01-01

    In the US, wildfires and prescribed burning present significant challenges to air regulatory agencies attempting to achieve and maintain compliance with air quality regulations. Fire emission factors (EF) are essential input for the emission models used to develop wildland fire emission inventories. Most previous studies quantifying wildland fire EF of temperate...

  12. Linking Remotely Sensed Functional Diversity of Structural Traits to the Radiative Regime of a Temperate Mixed Forest

    Science.gov (United States)

    Schneider, F. D.; Morsdorf, F.; Furrer, R.; Schmid, B.; Schaepman, M. E.

    2015-12-01

    Patterns of functional diversity reflect the inter- and intraspecific variability of plant traits and are linked to other aspects of biodiversity, environmental factors and ecosystem function. To study the patterns at plot and stand level, spatially continuous trait measurements are required. Remote sensing methods based on airborne observations can offer such continuous high-resolution measurements, resolving individual trees of a forest at a regional extent. The study was performed at the Laegern forest, a temperate mixed forest dominated by deciduous and coniferous trees (Fagus sylvatica, Picea abies; 47°28'42.0" N, 8°21'51.8" E, 682 m asl; Switzerland). Canopy height, plant area index and foliage height diversity were derived from full-waveform airborne laser scanning data. These structural traits were used to calculate functional richness, functional evenness and functional divergence at a range of scales. A Bayesian multiresolution scale analysis was used to infer the scales at which functional diversity patterns occur. The radiative regime of the forest was simulated using the 3D radiative transfer model DART. Using a voxel-based forest reconstruction allowed us to derive top of canopy, bottom of canopy and absorbed photosynthetically active radiation. The results of this study will provide new insights on linking forest canopy structure to the radiative regime of the forest. Light availability is a critical factor determining plant growth and competition. Within canopy light scattering is mainly driven by the arrangement of leaves and their leaf optical properties. Therefore, we expect a link between the structural complexity of the forest as encompassed by functional diversity and the light availability within and below the canopy. Ultimately, this information can be used in dynamic ecosystem models such as ED2, allowing us to predict the influence of functional diversity and radiative properties on ecosystem functioning under current conditions and

  13. Short- and medium-term effects of fuel reduction mulch treatments on soil nitrogen availability in Colorado conifer forests

    Science.gov (United States)

    C. C. Rhoades; M. A. Battaglia; M. E. Rocca; M. G. Ryan

    2012-01-01

    Mechanical fuel reduction treatments have been implemented on millions of hectares of western North American forests. The redistribution of standing forest biomass to the soil surface by mulching treatments has no ecological analog, and this practice may alter soil processes and forest productivity. We evaluated the effects of mulch addition on soil nitrogen...

  14. Rapid increase in log populations in drought-stressed mixed-conifer and ponderosa pine forests in northern Arizona

    Science.gov (United States)

    Joseph L. Ganey; Scott C. Vojta

    2012-01-01

    Down logs provide important ecosystem services in forests and affect surface fuel loads and fire behavior. Amounts and kinds of logs are influenced by factors such as forest type, disturbance regime, forest man-agement, and climate. To quantify potential short-term changes in log populations during a recent global- climate-change type drought, we sampled logs in mixed-...

  15. Principles and practices for the restoration of ponderosa pine and dry mixed-conifer forests of the Colorado Front Range

    Science.gov (United States)

    Robert N. Addington; Gregory H. Aplet; Mike A. Battaglia; Jennifer S. Briggs; Peter M. Brown; Antony S. Cheng; Yvette Dickinson; Jonas A. Feinstein; Kristen A. Pelz; Claudia M. Regan; Jim Thinnes; Rick Truex; Paula J. Fornwalt; Benjamin Gannon; Chad W. Julian; Jeffrey L. Underhill; Brett Wolk

    2018-01-01

    Wildfires have become larger and more severe over the past several decades on Colorado’s Front Range, catalyzing greater investments in forest management intended to mitigate wildfire risks. The complex ecological, social, and political context of the Front Range, however, makes forest management challenging, especially where multiple management goals including forest...

  16. Long-term overstory and understory change following logging and fire exclusion in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Eric E. Knapp; Carl N. Skinner; Malcolm P. North; Becky L. Estes

    2013-01-01

    In many forests of the western US, increased potential for fires of uncharacteristic intensity and severity is frequently attributed to structural changes brought about by fire exclusion, past land management practices, and climate. Extent of forest change and effect on understory vegetation over time are not well understood, but such information is useful to forest...

  17. Insect herbivores increase mortality and reduce tree seedling growth of some species in temperate forest canopy gaps

    Science.gov (United States)

    Burkepile, Deron E.; Parker, John D.

    2017-01-01

    Insect herbivores help maintain forest diversity through selective predation on seedlings of vulnerable tree species. Although the role of natural enemies has been well-studied in tropical systems, relatively few studies have experimentally manipulated insect abundance in temperate forests and tracked impacts over multiple years. We conducted a three-year experiment (2012–2014) deterring insect herbivores from seedlings in new treefall gaps in deciduous hardwood forests in Maryland. During this study, we tracked recruitment of all tree seedlings, as well as survivorship and growth of 889 individual seedlings from five tree species: Acer rubrum, Fagus grandifolia, Fraxinus spp., Liriodendron tulipifera, and Liquidambar styraciflua. Insect herbivores had little effect on recruitment of any tree species, although there was a weak indication that recruitment of A. rubrum was higher in the presence of herbivores. Insect herbivores reduced survivorship of L. tulipifera, but had no significant effects on A. rubrum, Fraxinus spp., F. grandifolia, or L. styraciflua. Additionally, insects reduced growth rates of early pioneer species A. rubrum, L. tulipifera, and L. styraciflua, but had little effect on more shade-tolerant species F. grandifolia and Fraxinus spp. Overall, by negatively impacting growth and survivorship of early pioneer species, forest insects may play an important but relatively cryptic role in forest gap dynamics, with potentially interesting impacts on the overall maintenance of diversity. PMID:28344904

  18. Insect herbivores increase mortality and reduce tree seedling growth of some species in temperate forest canopy gaps

    Directory of Open Access Journals (Sweden)

    Nathan P. Lemoine

    2017-03-01

    Full Text Available Insect herbivores help maintain forest diversity through selective predation on seedlings of vulnerable tree species. Although the role of natural enemies has been well-studied in tropical systems, relatively few studies have experimentally manipulated insect abundance in temperate forests and tracked impacts over multiple years. We conducted a three-year experiment (2012–2014 deterring insect herbivores from seedlings in new treefall gaps in deciduous hardwood forests in Maryland. During this study, we tracked recruitment of all tree seedlings, as well as survivorship and growth of 889 individual seedlings from five tree species: Acer rubrum, Fagus grandifolia, Fraxinus spp., Liriodendron tulipifera, and Liquidambar styraciflua. Insect herbivores had little effect on recruitment of any tree species, although there was a weak indication that recruitment of A. rubrum was higher in the presence of herbivores. Insect herbivores reduced survivorship of L. tulipifera, but had no significant effects on A. rubrum, Fraxinus spp., F. grandifolia, or L. styraciflua. Additionally, insects reduced growth rates of early pioneer species A. rubrum, L. tulipifera, and L. styraciflua, but had little effect on more shade-tolerant species F. grandifolia and Fraxinus spp. Overall, by negatively impacting growth and survivorship of early pioneer species, forest insects may play an important but relatively cryptic role in forest gap dynamics, with potentially interesting impacts on the overall maintenance of diversity.

  19. How much different are conifer forests? Comparison of Lepidoptera community in silver fir and black pine stands in Calabria (southern Italy

    Directory of Open Access Journals (Sweden)

    Infusino M

    2017-02-01

    Full Text Available The main coniferous forests of Calabria (Italy are certainly the Calabrian black pine (Pinus nigra calabrica forests of the Sila massif and the silver fir (Abies alba forests of the Serre Vibonesi. Despite these woodlands are of great importance both economically and from a conservationist point of view, biodiversity of moth has been investigated in a non occasional way only for the Sila Calabrian black pine forests, while the silver fir woods of the Serre have been only recently the subject of studies. Apart from increasing the knowledge on the biodiversity of the nocturnal Lepidoptera hosted by Calabrian coniferous forests, the aim of this study was to compare the sampled communities to find out the main differences and their causes. The sampling was conducted in 9 sites for each forest type, distributed so as to cover the different development stages of ecological succession, from open areas to mature woodlands. A light trap was monthly placed at each site from May to November 2015, for a total of 126 nights/trap. The two communities showed low similarity indices (Classic Jaccard = 0.396; Sorensen Classic = 0.568, due both to the component trophically linked to the dominant forest species and to the component linked to the herbaceous layer. In fact, the dominant species in the Calabrian black pine wood and in the silver fir wood (Thera firmata and Macaria liturata, respectively are absent or only occasionally present in the other forest type, and the community linked to the herbaceous layer is much better represented in the Calabrian black pine forest (29.7% of the total than in the silver fir forest (14.9%. The arrangement of the Sila landscape, where Calabrian black pine forests alternate with pastures, shrubs and cultivated fields, seems to be the cause of the increased presence of species related to non-forest vegetation layer, while the micro-climatic conditions of the silver fir forest, more humid and temperate, favor the presence of a

  20. Carbon balance of a partially harvested mixed conifer forest following mountain pine beetle attack and its comparison to a clear-cut

    Directory of Open Access Journals (Sweden)

    A. Mathys

    2013-08-01

    Full Text Available The recent mountain pine beetle (MPB outbreak has had an impact on the carbon (C cycling of lodgepole pine forests in British Columbia. This study examines how partial harvesting as a forest management response to MPB infestation affects the net ecosystem production (NEP of a mixed conifer forest (MPB-09 in Interior BC. MPB-09 is a 70-year-old stand that was partially harvested in 2009 after it had been attacked by MPB. Using the eddy-covariance technique, the C dynamics of the stand were studied over two years and compared to an adjacent clear-cut (MPB-09C over the summertime. The annual NEP at MPB-09 increased from −108 g C m−2 in 2010 to −57 g C m−2 in 2011. The increase of NEP was due to the associated increase in annual gross ecosystem photosynthesis (GEP from 812 g C m−2 in 2010 to 954 g C m−2 in 2011, exceeding the increase in annual respiration (Re from 920 g C m−2 to 1011 g C m−2 during the two years. During the four month period between June and September 2010, NEP at MPB-09C was −103 g C m−2, indicating high C losses in the clear-cut. MPB-09 was a C sink during the growing season of both years, increasing from 9 g C m−2 in 2010 to 47 g C m−2 in 2011. The increase of NEP in the partially harvested stand amounted to a recovery corresponding to a 26% increase in the maximum assimilation rate in the second year. This study shows that retaining the healthy residual forest can result in higher C sequestration of MPB-attacked stands compared to clear-cut harvesting.

  1. Modelling the decadal trend of ecosystem carbon fluxes demonstrates the important role of functional changes in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; Jansson, P.E.; van der Linden, Leon

    2013-01-01

    Temperate forests are globally important carbon sinks and stocks. Trends in net ecosystem exchange have been observed in a Danish beech forest and this trend cannot be entirely attributed to changing climatic drivers. This study sought to clarify the mechanisms responsible for the observed trend......, using a dynamic ecosystem model (CoupModel) and model data fusion with multiple constraints and model experiments. Experiments with different validation datasets showed that a multiple constraints model data fusion approach that included the annual tree growth, the seasonal canopy development......, the latent and sensible heat fluxes and the CO2 fluxes decreased the parameter uncertainty considerably compared to using CO2 fluxes as validation data alone. The fitted model was able to simulate the observed carbon fluxes well (R2=0.8, mean error=0.1gCm−2d−1) but did not reproduce the decadal (1997...

  2. Carbon stock and carbon turnover in boreal and temperate forests - Integration of remote sensing data and global vegetation models

    Science.gov (United States)

    Thurner, Martin; Beer, Christian; Carvalhais, Nuno; Forkel, Matthias; Tito Rademacher, Tim; Santoro, Maurizio; Tum, Markus; Schmullius, Christiane

    2016-04-01

    Long-term vegetation dynamics are one of the key uncertainties of the carbon cycle. There are large differences in simulated vegetation carbon stocks and fluxes including productivity, respiration and carbon turnover between global vegetation models. Especially the implementation of climate-related mortality processes, for instance drought, fire, frost or insect effects, is often lacking or insufficient in current models and their importance at global scale is highly uncertain. These shortcomings have been due to the lack of spatially extensive information on vegetation carbon stocks, which cannot be provided by inventory data alone. Instead, we recently have been able to estimate northern boreal and temperate forest carbon stocks based on radar remote sensing data. Our spatially explicit product (0.01° resolution) shows strong agreement to inventory-based estimates at a regional scale and allows for a spatial evaluation of carbon stocks and dynamics simulated by global vegetation models. By combining this state-of-the-art biomass product and NPP datasets originating from remote sensing, we are able to study the relation between carbon turnover rate and a set of climate indices in northern boreal and temperate forests along spatial gradients. We observe an increasing turnover rate with colder winter temperatures and longer winters in boreal forests, suggesting frost damage and the trade-off between frost adaptation and growth being important mortality processes in this ecosystem. In contrast, turnover rate increases with climatic conditions favouring drought and insect outbreaks in temperate forests. Investigated global vegetation models from the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), including HYBRID4, JeDi, JULES, LPJml, ORCHIDEE, SDGVM, and VISIT, are able to reproduce observation-based spatial climate - turnover rate relationships only to a limited extent. While most of the models compare relatively well in terms of NPP, simulated

  3. Root carbon inputs to the rhizosphere stimulate extracellular enzyme activity and increase nitrogen availability in temperate forest soils

    Science.gov (United States)

    Brzostek, E. R.; Phillips, R.; Dragoni, D.; Drake, J. E.; Finzi, A. C.

    2011-12-01

    The mobilization of nitrogen (N) from soil organic matter in temperate forest soils is controlled by the microbial production and activity of extracellular enzymes. The exudation of carbon (C) by tree roots into the rhizosphere may subsidize the microbial production of extracellular enzymes in the rhizosphere and increase the access of roots to N. The objective of this research was to investigate whether rates of root exudation and the resulting stimulation of extracellular enzyme activity in the rhizosphere (i.e., rhizosphere effect) differs between tree species that form associations with ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungi. This research was conducted at two temperate forest sites, the Harvard Forest (HF) in Central MA and the Morgan Monroe State Forest (MMSF) in Southern IN. At the HF, we measured rates of root exudation and the rhizosphere effects on enzyme activity, N cycling, and C mineralization in AM and ECM soils. At the MMSF, we recently girdled AM and ECM dominated plots to examine the impact of severing belowground C allocation on rhizosphere processes. At both sites, the rhizosphere effect on proteolytic, chitinolytic and ligninolytic enzyme activities was greater in ECM soils than in AM soils. In particular, higher rates of proteolytic enzyme activity increased the availability of amino acid-N in ECM rhizospheres relative to the bulk soils. Further, this stimulation of enzyme activity was directly correlated with higher rates of C mineralization in the rhizosphere than in the bulk soil. Although not significantly different between species, root exudation of C comprised 3-10% of annual gross primary production at the HF. At the MMSF, experimental girdling led to a larger decline in soil respiration and enzyme activity in ECM plots than in AM plots. In both ECM and AM soils, however, girdling resulted in equivalent rates of enzyme activity in rhizosphere and corresponding bulk soils. The results of this study contribute to the

  4. Effects of diffuse radiation on carbon and water fluxes of a high latitude temperate deciduous forest

    Science.gov (United States)

    Wang, Sheng; Ibrom, Andreas; Pilegaard, Kim; Bauer-Gottwein, Peter; Garcia, Monica

    2017-04-01

    Ecosystem carbon and water fluxes are controlled by the interplay of biophysical factors such as solar radiation, temperature and soil moisture. In high latitudes, cloudy days are prevalent with a low amount of solar radiation and a higher proportion of diffuse radiation. For instance, in Denmark 90% of all days are non-clear (fraction of direct radiation radiation, which can modify the coupled photosynthesis and transpiration rates in future. This study aims to evaluate effects of diffuse radiation on the ecosystem carbon and water fluxes in a temperate deciduous forest using long term eddy covariance observations. Eddy covariance records (Gross Primary Productivity: GPP; Evapotranspiration: ET) from 2002 to 2012, field data, Normalized Difference Vegetation Index (NDVI) from Moderate Resolution Imaging Spectroradiometer (MODIS), and sap flow data during the period of 2009-2011 at Sorø, a Danish beech forest flux site, were used for analysis. A Cloudiness Index (CI), which is based on actual and potential shortwave incoming radiation and can indicate the proportion of diffuse radiation, was used. First, multiple regression based path analysis was applied to daily and monthly observations to partition direct and indirect effects from CI to GPP and ET. Results indicate diffuse radiation increases the light use efficiency (LUE) with CI being as important as other constraints, e.g. air temperature (Tair), vapor pressure deficit (VPD) and Photosynthetically Active Radiation (PAR), on regulating LUE. An increase of the CI value of 0.1 can increase maximum LUE by about 0.286 gC•MJ-1. Following PAR and LAI, CI has the third largest effects on GPP. For ET, path analysis showed the impact of CI is limited. Further, the CI constraint was added to two physiologically based models for estimating GPP (LUE, Potter et al., 1993) and ET (Priestley-Taylor Jet Propulsion Laboratory, PT-JPL, Fisher et al., 2008) at the daily time scale to assess model improvement. When considering

  5. [Temporal variation of soil greenhouse gases fluxes in a cold-temperate Larix gmelinii forest in Inner Mongolia, China].

    Science.gov (United States)

    Ma, Xiu-Zhi; Zhang, Qiu-Liang; Li, Chang-Sheng; Chen, Gao-Wa; Wang, Fei

    2012-08-01

    By using static chamber-gas chromatograph technique, an in situ measurement was conducted on the soil CH4, CO2, and N2O fluxes in a cold-temperate Larix gmelinii forest in Inner Mongolia from June to September 2007, aimed to understand the diurnal and seasonal variations of soil greenhouse gasses fluxes and their relations with the associated environmental factors in L. gmelinii forests in cold-temperate zone. In growth season, the soil in the L. gmelinii forest was the sink of atmospheric CH4, with the flux ranged from 22.3 to 107.8 microg CH4-C x m(-2) x h(-1). The mean monthly uptake of CH4 in June, July, August, and September was 34.0 +/- 7.1, 71.4 +/- 9.4, 86.3 +/- 7.9, and 40.7 +/- 6.2 microg x m(-2) x h(-1), respectively. The mean diurnal flux of soil CH4 from June to September showed the same variation trend, i. e., peaked at 10:00 am. The diurnal variation of soil CO2 flux showed an obvious double-peak, and the mean monthly CO2 flux was in the order of July > August > June > September. Soil N2O flux varied dramatically from -9.1 to 31.7 microg x m(-2) x h(-1). Soil temperature and humidity were the main factors affecting the CH4 and CO2 fluxes, and soil temperature mainly affected the N2O flux. In the L. gmelinii forest, the CH4, CO2, and N2O fluxes measured at 10:00 am could represent the diurnal CH4, CO2, and N2O fluxes on the same day.

  6. Methane fluxes measured by eddy covariance and static chamber techniques at a temperate forest in central ontario, Canada

    Science.gov (United States)

    Wang, J. M.; Murphy, J. G.; Geddes, J. A.; Winsborough, C. L.; Basiliko, N.; Thomas, S. C.

    2012-12-01

    Methane flux measurements were carried out at a temperate forest (Haliburton Forest and Wildlife Reserve) in central Ontario (45°17´11´´ N, 78°32´19´´ W) from June-October, 2011. Continuous measurements were made by an off-axis integrated cavity output spectrometer Fast Greenhouse Gas Analyzer (FGGA) from Los Gatos Research Inc. that measures methane (CH4) at 10 Hz sampling rates. Fluxes were calculated from the gas measurements in conjunction with wind data collected by a 3-D sonic anemometer using the eddy covariance (EC) method. Observed methane fluxes showed net uptake of CH4 over the measurement period with an average uptake flux (± standard deviation of the mean) of -2.7 ± 0.13 nmol m-2 s-1. Methane fluxes showed a seasonal progression with average rates of uptake increasing from June through September and remaining high in October. This pattern was consistent with a decreasing trend in soil moisture content at the monthly time scale. On the diurnal timescale, there was evidence of increased uptake during the day, when the mid-canopy wind speed was at a maximum. These patterns suggest that substrate supply of CH4 and oxygen to methanotrophs, and in certain cases hypoxic soil conditions supporting methanogenesis in low-slope areas, drive the observed variability in fluxes. A network of soil static chambers used at the tower site showed close agreement with the eddy covariance flux measurements. This suggests that soil-level microbial processes, and not abiological leaf-level CH4 production, drive overall CH4 dynamics in temperate forest ecosystems such as Haliburton Forest.

  7. Role of forest conservation in lessening land degradation in a temperate region: the Monarch Butterfly Biosphere Reserve, Mexico.

    Science.gov (United States)

    Manzo-Delgado, Lilia; López-García, José; Alcántara-Ayala, Irasema

    2014-06-01

    With international concern about the rates of deforestation worldwide, particular attention has been paid to Latin America. Forest conservation programmes in Mexico include Payment for Environmental Services (PES), a scheme that has been successfully introduced in the Monarch Butterfly Biosphere Reserve. To seek further evidence of the role of PES in lessening land degradation processes in a temperate region, the conservation state of the Cerro Prieto ejido within the Reserve was assessed by an analysis of changes in vegetation cover and land-use between 1971 and 2013. There were no changes in the total forest surface area, but the relative proportions of the different classes of cover density had changed. In 1971, closed and semi-closed forest occupied 247.81 ha and 5.38 ha, 82.33% and 1.79% of the total area of the ejido, respectively. By 2013, closed forest had decreased to 230.38 ha (76.54% of the ejido), and semi-closed cover was 17.23 ha (5.72% of the ejido), suggesting that some semi-closed forest had achieved closed status. The final balance between forest losses and recovery was: 29.63 ha were lost, whereas 13.72 ha were recovered. Losses were mainly linked to a sanitation harvest programme to control the bark beetle Scolytus mundus. Ecotourism associated with forest conservation in the Cerro Prieto ejido has been considered by inhabitants as a focal alternative for economic development. Consequently, it is essential to develop a well-planned and solidly structured approach based on social cohesion to foster a community-led sustainable development at local level. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Influence of Anthropogenic Disturbances on Stand Structural Complexity in Andean Temperate Forests: Implications for Managing Key Habitat for Biodiversity

    Science.gov (United States)

    2017-01-01

    Forest attributes and their abundances define the stand structural complexity available as habitat for faunal biodiversity; however, intensive anthropogenic disturbances have the potential to degrade and simplify forest stands. In this paper we develop an index of stand structural complexity and show how anthropogenic disturbances, namely fire, logging, livestock, and their combined presence, affect stand structural complexity in a southern Global Biodiversity Hotspot. From 2011 to 2013, we measured forest structural attributes as well as the presence of anthropogenic disturbances in 505 plots in the Andean zone of the La Araucanía Region, Chile. In each plot, understory density, coarse woody debris, number of snags, tree diameter at breast height, and litter depth were measured, along with signs of the presence of anthropogenic disturbances. Ninety-five percent of the plots showed signs of anthropogenic disturbance (N = 475), with the combined presence of fire, logging, and livestock being the most common disturbance (N = 222; 44% of plots). The lowest values for the index were measured in plots combining fire, logging, and livestock. Undisturbed plots and plots with the presence of relatively old fires (> 70 years) showed the highest values for the index of stand structural complexity. Our results suggest that secondary forests forests should be managed to retain structural attributes, including understory density (7.2 ± 2.5 # contacts), volume of CWD (22.4 ± 25.8 m3/ha), snag density (94.4 ± 71.0 stems/ha), stand basal area (61.2 ± 31.4 m2/ha), and litter depth (7.5 ± 2.7 cm). Achieving these values will increase forest structural complexity, likely benefiting a range of faunal species in South American temperate forests. PMID:28068349

  9. Distribution of wild mammal assemblages along an urban-rural-forest landscape gradient in warm-temperate East Asia.

    Science.gov (United States)

    Saito, Masayuki; Koike, Fumito

    2013-01-01

    Urbanization may alter mammal assemblages via habitat loss, food subsidies, and other factors related to human activities. The general distribution patterns of wild mammal assemblages along urban-rural-forest landscape gradients have not been studied, although many studies have focused on a single species or taxon, such as rodents. We quantitatively evaluated the effects of the urban-rural-forest gradient and spatial scale on the distributions of large and mid-sized mammals in the world's largest metropolitan area in warm-temperate Asia using nonspecific camera-trapping along two linear transects spanning from the urban zone in the Tokyo metropolitan area to surrounding rural and forest landscapes. Many large and mid-sized species generally decreased from forest landscapes to urban cores, although some species preferred anthropogenic landscapes. Sika deer (Cervus nippon), Reeves' muntjac (Muntiacus reevesi), Japanese macaque (Macaca fuscata), Japanese squirrel (Sciurus lis), Japanese marten (Martes melampus), Japanese badger (Meles anakuma), and wild boar (Sus scrofa) generally dominated the mammal assemblage of the forest landscape. Raccoon (Procyon lotor), raccoon dog (Nyctereutes procyonoides), and Japanese hare (Lepus brachyurus) dominated the mammal assemblage in the intermediate zone (i.e., rural and suburban landscape). Cats (feral and free-roaming housecats; Felis catus) were common in the urban assemblage. The key spatial scales for forest species were more than 4000-m radius, indicating that conservation and management plans for these mammal assemblages should be considered on large spatial scales. However, small green spaces will also be important for mammal conservation in the urban landscape, because an indigenous omnivore (raccoon dog) had a smaller key spatial scale (500-m radius) than those of forest mammals. Urbanization was generally the most important factor in the distributions of mammals, and it is necessary to consider the spatial scale of

  10. Distribution of Wild Mammal Assemblages along an Urban–Rural–Forest Landscape Gradient in Warm-Temperate East Asia

    Science.gov (United States)

    Saito, Masayuki; Koike, Fumito

    2013-01-01

    Urbanization may alter mammal assemblages via habitat loss, food subsidies, and other factors related to human activities. The general distribution patterns of wild mammal assemblages along urban–rural–forest landscape gradients have not been studied, although many studies have focused on a single species or taxon, such as rodents. We quantitatively evaluated the effects of the urban–rural–forest gradient and spatial scale on the distributions of large and mid-sized mammals in the world's largest metropolitan area in warm-temperate Asia using nonspecific camera-trapping along two linear transects spanning from the urban zone in the Tokyo metropolitan area to surrounding rural and forest landscapes. Many large and mid-sized species generally decreased from forest landscapes to urban cores, although some species preferred anthropogenic landscapes. Sika deer (Cervus nippon), Reeves' muntjac (Muntiacus reevesi), Japanese macaque (Macaca fuscata), Japanese squirrel (Sciurus lis), Japanese marten (Martes melampus), Japanese badger (Meles anakuma), and wild boar (Sus scrofa) generally dominated the mammal assemblage of the forest landscape. Raccoon (Procyon lotor), raccoon dog (Nyctereutes procyonoides), and Japanese hare (Lepus brachyurus) dominated the mammal assemblage in the intermediate zone (i.e., rural and suburban landscape). Cats (feral and free-roaming housecats; Felis catus) were common in the urban assemblage. The key spatial scales for forest species were more than 4000-m radius, indicating that conservation and management plans for these mammal assemblages should be considered on large spatial scales. However, small green spaces will also be important for mammal conservation in the urban landscape, because an indigenous omnivore (raccoon dog) had a smaller key spatial scale (500-m radius) than those of forest mammals. Urbanization was generally the most important factor in the distributions of mammals, and it is necessary to consider the spatial

  11. Distribution of wild mammal assemblages along an urban-rural-forest landscape gradient in warm-temperate East Asia.

    Directory of Open Access Journals (Sweden)

    Masayuki Saito

    Full Text Available Urbanization may alter mammal assemblages via habitat loss, food subsidies, and other factors related to human activities. The general distribution patterns of wild mammal assemblages along urban-rural-forest landscape gradients have not been studied, although many studies have focused on a single species or taxon, such as rodents. We quantitatively evaluated the effects of the urban-rural-forest gradient and spatial scale on the distributions of large and mid-sized mammals in the world's largest metropolitan area in warm-temperate Asia using nonspecific camera-trapping along two linear transects spanning from the urban zone in the Tokyo metropolitan area to surrounding rural and forest landscapes. Many large and mid-sized species generally decreased from forest landscapes to urban cores, although some species preferred anthropogenic landscapes. Sika deer (Cervus nippon, Reeves' muntjac (Muntiacus reevesi, Japanese macaque (Macaca fuscata, Japanese squirrel (Sciurus lis, Japanese marten (Martes melampus, Japanese badger (Meles anakuma, and wild boar (Sus scrofa generally dominated the mammal assemblage of the forest landscape. Raccoon (Procyon lotor, raccoon dog (Nyctereutes procyonoides, and Japanese hare (Lepus brachyurus dominated the mammal assemblage in the intermediate zone (i.e., rural and suburban landscape. Cats (feral and free-roaming housecats; Felis catus were common in the urban assemblage. The key spatial scales for forest species were more than 4000-m radius, indicating that conservation and management plans for these mammal assemblages should be considered on large spatial scales. However, small green spaces will also be important for mammal conservation in the urban landscape, because an indigenous omnivore (raccoon dog had a smaller key spatial scale (500-m radius than those of forest mammals. Urbanization was generally the most important factor in the distributions of mammals, and it is necessary to consider the spatial scale

  12. Strong thermal acclimation of photosynthesis in tropical and temperate wet-forest tree species: the importance of altered Rubisco content.

    Science.gov (United States)

    Scafaro, Andrew P; Xiang, Shuang; Long, Benedict M; Bahar, Nur H A; Weerasinghe, Lasantha K; Creek, Danielle; Evans, John R; Reich, Peter B; Atkin, Owen K

    2017-07-01

    Understanding of the extent of acclimation of light-saturated net photosynthesis (A n ) to temperature (T), and associated underlying mechanisms, remains limited. This is a key knowledge gap given the importance of thermal acclimation for plant functioning, both under current and future higher temperatures, limiting the accuracy and realism of Earth system model (ESM) predictions. Given this, we analysed and modelled T-dependent changes in photosynthetic capacity in 10 wet-forest tree species: six from temperate forests and four from tropical forests. Temperate and tropical species were each acclimated to three daytime growth temperatures (T growth ): temperate - 15, 20 and 25 °C; tropical - 25, 30 and 35 °C. CO 2 response curves of A n were used to model maximal rates of RuBP (ribulose-1,5-bisphosphate) carboxylation (V cmax ) and electron transport (J max ) at each treatment's respective T growth and at a common measurement T (25 °C). SDS-PAGE gels were used to determine abundance of the CO 2 -fixing enzyme, Rubisco. Leaf chlorophyll, nitrogen (N) and mass per unit leaf area (LMA) were also determined. For all species and T growth , A n at current atmospheric CO 2 partial pressure was Rubisco-limited. Across all species, LMA decreased with increasing T growth . Similarly, area-based rates of V cmax at a measurement T of 25 °C (V cmax 25 ) linearly declined with increasing T growth , linked to a concomitant decline in total leaf protein per unit leaf area and Rubisco as a percentage of leaf N. The decline in Rubisco constrained V cmax and A n for leaves developed at higher T growth and resulted in poor predictions of photosynthesis by currently widely used models that do not account for T growth -mediated changes in Rubisco abundance that underpin the thermal acclimation response of photosynthesis in wet-forest tree species. A new model is proposed that accounts for the effect of T growth -mediated declines in V cmax 25 on A n , complementing current

  13. Simulating Canopy-Level Solar Induced Fluorescence with CLM-SIF 4.5 at a Sub-Alpine Conifer Forest in the Colorado Rockies

    Science.gov (United States)

    Raczka, B. M.; Bowling, D. R.; Lin, J. C.; Lee, J. E.; Yang, X.; Duarte, H.; Zuromski, L.

    2017-12-01

    Forests of the Western United States are prone to drought, temperature extremes, forest fires and insect infestation. These disturbance render carbon stocks and land-atmosphere carbon exchanges highly variable and vulnerable to change. Regional estimates of carbon exchange from terrestrial ecosystem models are challenged, in part, by a lack of net ecosystem exchange observations (e.g. flux towers) due to the complex mountainous terrain. Alternatively, carbon estimates based on light use efficiency models that depend upon remotely-sensed greenness indices are challenged due to a weak relationship with GPP during the winter season. Recent advances in the retrieval of remotely sensed solar induced fluorescence (SIF) have demonstrated a strong seasonal relationship between GPP and SIF for deciduous, grass and, to a lesser extent, conifer species. This provides an important opportunity to use remotely-sensed SIF to calibrate terrestrial ecosystem models providing a more accurate regional representation of biomass and carbon exchange across mountainous terrain. Here we incorporate both leaf-level fluorescence and leaf-to-canopy radiative transfer represented by the SCOPE model into CLM 4.5 (CLM-SIF). We simulate canopy level fluorescence at a sub-alpine forest site (Niwot Ridge, Colorado) and test whether these simulations reproduce remotely-sensed SIF from a satellite (GOME2). We found that the average peak SIF during the growing season (yrs 2007-2013) was similar between the model and satellite observations (within 15%); however, simulated SIF during the winter season was significantly greater than the satellite observations (5x higher). This implies that the fluorescence yield is overestimated by the model during the winter season. It is important that the modeled representation of seasonal fluorescence yield is improved to provide an accurate seasonal representation of SIF across the Western United States.

  14. Photochemical smog effects in mixed conifer forests along a natural gradient of ozone and nitrogen deposition in the San Bernardino Mountains.

    Science.gov (United States)

    Arbaugh, Michael; Bytnerowicz, Andrzej; Grulke, Nancy; Fenn, Mark; Poth, Mark; Temple, Patrick; Miller, Paul

    2003-06-01

    Toxic effects of photochemical smog on ponderosa and Jeffrey pines in the San Bernardino Mountains were discovered in the 1950s. It was revealed that ozone is the main cause of foliar injury manifested as chlorotic mottle and premature needle senescence. Various morphological, physiological and biochemical alterations in the affected plants have been reported over a period of about 40 years of multidisciplinary research. Recently, the focus of research has shifted from studying the effects of ozone to multiple pollutant effects. Recent studies have indicated that the combination of ozone and nitrogen may alter biomass allocation in pines towards that of deciduous trees, accelerate litter accumulation, and increase carbon sequestration rates in heavily polluted forests. Further study of the effects of multiple pollutants, and their long-term consequences on the mixed conifer ecosystem, cannot be adequately done using the original San Bernardino Mountains Air Pollution Gradient network. To correct deficiencies in the design, the new site network is being configured for long-term studies on multiple air pollutant concentrations and deposition, physiological and biochemical changes in trees, growth and composition of over-story species, biogeochemical cycling including carbon cycling and sequestration, water quality, and biodiversity of forest ecosystems. Eleven sites have been re-established. A comparison of 1974 stand composition with data from 2000 stand composition indicate that significant changes in species composition have occurred at some sites with less change at other sites. Moist, high-pollution sites have experienced the greatest amount of forest change, while dryer low-pollution sites have experienced the least amount of stand change. In general, ponderosa pine had the lowest basal area increases and the highest mortality across the San Bernardino Mountains.

  15. Fuel load modeling from mensuration attributes in temperate forests in northern Mexico

    Science.gov (United States)

    Maricela Morales-Soto; Marín Pompa-Garcia

    2013-01-01

    The study of fuels is an important factor in defining the vulnerability of ecosystems to forest fires. The aim of this study was to model a dead fuel load based on forest mensuration attributes from forest management inventories. A scatter plot analysis was performed and, from explanatory trends between the variables considered, correlation analysis was carried out...

  16. Short Communication. Comparing flammability traits among fire-stricken (low elevation and non fire-stricken (high elevation conifer forest species of Europe: A test of the Mutch hypothesis

    Directory of Open Access Journals (Sweden)

    A. P. Dimitrakopoulos

    2013-04-01

    Full Text Available Aim of study. The flammability of the main coniferous forest species of Europe, divided into two groups according to their fire regime and altitudinal distribution, was tested in an effort to detect species-specific differences that may have an influence on community-wide fire regimes.Area of study. Conifer species comprising low- and high-elevation forests in Europe.Materials and Methods. The following conifer species were tested: low elevation; Pinus halepensis (Aleppo pine, Pinus brutia (Turkish pine, Pinus pinaster (maritime pine, Pinus pinea (stone pine and Cupressus sempervirens (cypress, high elevation (i.e., above 600 m a.s.l.; Pinus sylvestris (Scots pine, Abies alba (white fir, Picea excelsa (Norway spruce, Abies borissii regis (Macedonian fir and Pinus nigra (black pine. Flammability assessment (time-to-ignition and ignition temperature was conducted by an innovative ignition apparatus, heat content was measured with an IKA Adiabatic Bomb Calorimeter and ash content by heating 5 g of plant material in a muffle furnace at 650ºC for 1 h. Differences among species was statistically analysed by Duncan’s multiple comparison test.Main results. The results did not distinguish separate groups among traits between fire- and non-fire-stricken communities at the individual species level.Research highlights. Differences in fire regimes among low and high elevation conifer forests could be attributed either to differences in flammability of the plant communities as a whole (i.e., fuelbed or canopy properties vs. individual fuel properties or to other factors (climatic or anthropogenic.Key words: flammability; ignitability; heat content; ash content; conifer species; Mutch hypothesis.

  17. Incorporating microbial dormancy dynamics into soil decomposition models to improve quantification of soil carbon dynamics of northern temperate forests

    Energy Technology Data Exchange (ETDEWEB)

    He, Yujie [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Yang, Jinyan [Univ. of Georgia, Athens, GA (United States). Warnell School of Forestry and Natural Resources; Northeast Forestry Univ., Harbin (China). Center for Ecological Research; Zhuang, Qianlai [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Purdue Univ., West Lafayette, IN (United States). Dept. of Agronomy; Harden, Jennifer W. [U.S. Geological Survey, Menlo Park, CA (United States); McGuire, Anthony D. [Alaska Cooperative Fish and Wildlife Research Unit, U.S. Geological Survey, Univ. of Alaska, Fairbanks, AK (United States). U.S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit; Liu, Yaling [Purdue Univ., West Lafayette, IN (United States). Dept. of Earth, Atmospheric, and Planetary Sciences; Wang, Gangsheng [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Climate Change Science Inst. and Environmental Sciences Division; Gu, Lianhong [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Division

    2015-11-20

    Soil carbon dynamics of terrestrial ecosystems play a significant role in the global carbon cycle. Microbial-based decomposition models have seen much growth recently for quantifying this role, yet dormancy as a common strategy used by microorganisms has not usually been represented and tested in these models against field observations. Here in this study we developed an explicit microbial-enzyme decomposition model and examined model performance with and without representation of microbial dormancy at six temperate forest sites of different forest types. We then extrapolated the model to global temperate forest ecosystems to investigate biogeochemical controls on soil heterotrophic respiration and microbial dormancy dynamics at different temporal-spatial scales. The dormancy model consistently produced better match with field-observed heterotrophic soil CO2 efflux (RH) than the no dormancy model. Our regional modeling results further indicated that models with dormancy were able to produce more realistic magnitude of microbial biomass (<2% of soil organic carbon) and soil RH (7.5 ± 2.4 PgCyr-1). Spatial correlation analysis showed that soil organic carbon content was the dominating factor (correlation coefficient = 0.4-0.6) in the simulated spatial pattern of soil RH with both models. In contrast to strong temporal and local controls of soil temperature and moisture on microbial dormancy, our modeling results showed that soil carbon-to-nitrogen ratio (C:N) was a major regulating factor at regional scales (correlation coefficient = -0.43 to -0.58), indicating scale-dependent biogeochemical controls on microbial dynamics. Our findings suggest that incorporating microbial dormancy could improve the realism of microbial-based decomposition models and enhance the integration of soil experiments and mechanistically based modeling.

  18. Effects of management on aquatic tree-hole communities in temperate forests are mediated by detritus amount and water chemistry.

    Science.gov (United States)

    Gossner, Martin M; Lade, Peggy; Rohland, Anja; Sichardt, Nora; Kahl, Tiemo; Bauhus, Jürgen; Weisser, Wolfgang W; Petermann, Jana S

    2016-01-01

    Arthropod communities in water-filled tree holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. We hypothesized that increasing forest management intensity (ForMI) negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree hole size, detritus amount and changed water chemistry at the tree holes scale. We mapped 910 water-filled tree holes in two regions in Germany and studied 199 tree hole inhabiting arthropod communities. We found that increasing ForMI indeed significantly reduced arthropod abundance and richness in water-filled tree holes. The most important indirect effects of management intensity on tree hole community structure were the reduced amounts of detritus for the tree hole inhabiting organisms and changed water chemistry at the tree hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree holes. However, regional species richness in tree holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management-driven increase in plant diversity at the forest stand scale affected communities of individual tree holes, for example via resource availability for adults. Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water-filled tree holes. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  19. Spatial variability in microclimate in a mixed-conifer forest before and after thinning and burning treatments

    Science.gov (United States)

    Siyan Ma; Amy Concilio; Brian Oakley; Malcolm North; Jiquan. Chen

    2010-01-01

    In the western United States, mechanical thinning and prescribed fire are common forest management practices aimed at reducing potential wildfire severity and restoring historic forest structure, yet their effects on forestmicroclimate conditions are not well understood. We collected microclimate data between 1998 and 2003 in amixed-coniferforest in California's...

  20. Historical and current landscape-scale ponderosa pine and mixed conifer forest structure in the Southern Sierra Nevada

    Science.gov (United States)

    Scott L. Stephens; Jamie M. Lydersen; Brandon M. Collins; Danny L. Fry; Marc D. Meyer

    2015-01-01

    Many managers today are tasked with restoring forests to mitigate the potential for uncharacteristically severe fire. One challenge to this mandate is the lack of large-scale reference information on forest structure prior to impacts from Euro-American settlement. We used a robust 1911 historical dataset that covers a large geographic extent (>10,000 ha) and has...

  1. Decoupling of unpolluted temperate forests from rock nutrient sources revealed by natural 87Sr/86Sr and 84Sr tracer addition

    Science.gov (United States)

    Kennedy, Martin J.; Hedin, Lars O.; Derry, Louis A.

    2002-01-01

    An experimental tracer addition of 84Sr to an unpolluted temperate forest site in southern Chile, as well as the natural variation of 87Sr/86Sr within plants and soils, indicates that mechanisms in shallow soil organic horizons are of key importance for retaining and recycling atmospheric cation inputs at scales of decades or less. The dominant tree species Nothofagus nitida feeds nearly exclusively (>90%) on cations of atmospheric origin, despite strong variations in tree size and location in the forest landscape. Our results illustrate that (i) unpolluted temperate forests can become nutritionally decoupled from deeper weathering processes, virtually functioning as atmospherically fed ecosystems, and (ii) base cation turnover times are considerably more rapid than previously recognized in the plant available pool of soil. These results challenge the prevalent paradigm that plants largely feed on rock-derived cations and have important implications for understanding sensitivity of forests to air pollution. PMID:12119394

  2. Multiple metrics of diversity have different effects on temperate forest functioning over succession.

    Science.gov (United States)

    Yuan, Zuoqiang; Wang, Shaopeng; Gazol, Antonio; Mellard, Jarad; Lin, Fei; Ye, Ji; Hao, Zhanqing; Wang, Xugao; Loreau, Michel

    2016-12-01

    Biodiversity can be measured by taxonomic, phylogenetic, and functional diversity. How ecosystem functioning depends on these measures of diversity can vary from site to site and depends on successional stage. Here, we measured taxonomic, phylogenetic, and functional diversity, and examined their relationship with biomass in two successional stages of the broad-leaved Korean pine forest in northeastern China. Functional diversity was calculated from six plant traits, and aboveground biomass (AGB) and coarse woody productivity (CWP) were estimated using data from three forest censuses (10 years) in two large fully mapped forest plots (25 and 5 ha). 11 of the 12 regressions between biomass variables (AGB and CWP) and indices of diversity showed significant positive relationships, especially those with phylogenetic diversity. The mean tree diversity-biomass regressions increased from 0.11 in secondary forest to 0.31 in old-growth forest, implying a stronger biodiversity effect in more mature forest. Multi-model selection results showed that models including species richness, phylogenetic diversity, and single functional traits explained more variation in forest biomass than other candidate models. The models with a single functional trait, i.e., leaf area in secondary forest and wood density in mature forest, provided better explanations for forest biomass than models that combined all six functional traits. This finding may reflect different strategies in growth and resource acquisition in secondary and old-growth forests.

  3. Forest impacts on snow accumulation and ablation across an elevation gradient in a temperate montane environment

    Science.gov (United States)

    Roth, Travis R.; Nolin, Anne W.

    2017-11-01

    Forest cover modifies snow accumulation and ablation rates via canopy interception and changes in sub-canopy energy balance processes. However, the ways in which snowpacks are affected by forest canopy processes vary depending on climatic, topographic and forest characteristics. Here we present results from a 4-year study of snow-forest interactions in the Oregon Cascades. We continuously monitored snow and meteorological variables at paired forested and open sites at three elevations representing the Low, Mid, and High seasonal snow zones in the study region. On a monthly to bi-weekly basis, we surveyed snow depth and snow water equivalent across 900 m transects connecting the forested and open pairs of sites. Our results show that relative to nearby open areas, the dense, relatively warm forests at Low and Mid sites impede snow accumulation via canopy snow interception and increase sub-canopy snowpack energy inputs via longwave radiation. Compared with the Forest sites, snowpacks are deeper and last longer in the Open site at the Low and Mid sites (4-26 and 11-33 days, respectively). However, we see the opposite relationship at the relatively colder High sites, with the Forest site maintaining snow longer into the spring by 15-29 days relative to the nearby Open site. Canopy interception efficiency (CIE) values at the Low and Mid Forest sites averaged 79 and 76 % of the total event snowfall, whereas CIE was 31 % at the lower density High Forest site. At all elevations, longwave radiation in forested environments appears to be the primary energy component due to the maritime climate and forest presence, accounting for 93, 92, and 47 % of total energy inputs to the snowpack at the Low, Mid, and High Forest sites, respectively. Higher wind speeds in the High Open site significantly increase turbulent energy exchanges and snow sublimation. Lower wind speeds in the High Forest site create preferential snowfall deposition. These results show the importance of

  4. Edge effects on N2O, NO and CH4 fluxes in two temperate forests.

    Science.gov (United States)

    Remy, Elyn; Gasche, Rainer; Kiese, Ralf; Wuyts, Karen; Verheyen, Kris; Boeckx, Pascal

    2017-01-01

    Forest ecosystems may act as sinks or sources of nitrogen (N) and carbon (C) compounds, such as the climate relevant trace gases nitrous oxide (N 2 O), nitric oxide (NO) and methane (CH 4 ). Forest edges, which catch more atmospheric deposition, have become important features in European landscapes and elsewhere. Here, we implemented a fully automated measuring system, comprising static and dynamic measuring chambers determining N 2 O, NO and CH 4 fluxes along an edge-to-interior transect in an oak (Q. robur) and a pine (P. nigra) forest in northern Belgium. Each forest was monitored during a 2-week measurement campaign with continuous measurements every 2h. NO emissions were 9-fold higher than N 2 O emissions. The fluxes of NO and CH 4 differed between forest edge and interior, but not for N 2 O. This edge effect was more pronounced in the oak than in the pine forest. In the oak forest, edges emitted less NO (on average 60%) and took up more CH 4 (on average 177%). This suggests that landscape structure can play a role in the atmospheric budgets of these climate relevant trace gases. Soil moisture variation between forest edge and interior was a key variable explaining the magnitude of NO and CH 4 fluxes in our measurement campaign. To better understand the environmental impact of N and C trace gas fluxes from forest edges, additional and long-term measurements in other forest edges are required. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Evaluation of climate-related carbon turnover processes in global vegetation models for boreal and temperate forests.

    Science.gov (United States)

    Thurner, Martin; Beer, Christian; Ciais, Philippe; Friend, Andrew D; Ito, Akihiko; Kleidon, Axel; Lomas, Mark R; Quegan, Shaun; Rademacher, Tim T; Schaphoff, Sibyll; Tum, Markus; Wiltshire, Andy; Carvalhais, Nuno

    2017-08-01

    Turnover concepts in state-of-the-art global vegetation models (GVMs) account for various processes, but are often highly simplified and may not include an adequate representation of the dominant processes that shape vegetation carbon turnover rates in real forest ecosystems at a large spatial scale. Here, we evaluate vegetation carbon turnover processes in GVMs participating in the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP, including HYBRID4, JeDi, JULES, LPJml, ORCHIDEE, SDGVM, and VISIT) using estimates of vegetation carbon turnover rate (k) derived from a combination of remote sensing based products of biomass and net primary production (NPP). We find that current model limitations lead to considerable biases in the simulated biomass and in k (severe underestimations by all models except JeDi and VISIT compared to observation-based average k), likely contributing to underestimation of positive feedbacks of the northern forest carbon balance to climate change caused by changes in forest mortality. A need for improved turnover concepts related to frost damage, drought, and insect outbreaks to better reproduce observation-based spatial patterns in k is identified. As direct frost damage effects on mortality are usually not accounted for in these GVMs, simulated relationships between k and winter length in boreal forests are not consistent between different regions and strongly biased compared to the observation-based relationships. Some models show a response of k to drought in temperate forests as a result of impacts of water availability on NPP, growth efficiency or carbon balance dependent mortality as well as soil or litter moisture effects on leaf turnover or fire. However, further direct drought effects such as carbon starvation (only in HYBRID4) or hydraulic failure are usually not taken into account by the investigated GVMs. While they are considered dominant large-scale mortality agents, mortality mechanisms related to insects and

  6. Sequential effects of severe drought and defoliation on tree growth and survival in a diverse temperate mesic forest

    Science.gov (United States)

    Matthes, J. H.; Pederson, N.; David, O.; Martin-Benito, D.

    2017-12-01

    Understanding the effects of climate change and biotic disturbance within diverse temperate mesic forests is complicated by the need to scale between impacts within individuals and across species in the community. It is not clear how these impacts within individuals and across a community influences the stand- and regional-scale response. Furthermore, co-occurring or sequential disturbances can make it challenging to interpret forest responses from observational data. In the northeastern United States, the 1960s drought was perhaps the most severe period of climatic stress within the past 300 years and negatively impacted the growth of individual trees across all species, but unevenly. Additionally, in 1981 the northeast experienced an outbreak of the defoliator Lymantria dispar, which preferentially consumes oak leaves, but in 1981 impacted a high proportion of other species as well. To investigate the effects of drought (across functional groups) and defoliation (within a functional group), we combined a long-term tree-ring dataset from an old-growth forest within the Palmaghatt Ravine in New York with a version of the Ecosystem Demography model that includes a scheme for representing forest insects and pathogens. We explored the sequential impacts of severe drought and defoliation on tree growth, community composition, and ecosystem-atmosphere interactions (carbon, water, and heat flux). W­e also conducted a set of modeling experiments with climate and defoliation disturbance scenarios to bound the potential long-term response of this forest to co-occurring and sequential drought-defoliator disturbances over the next fifty years.

  7. How plant diversity features change across ecological species groups? A case study of a temperate deciduous forest in northern Iran

    Directory of Open Access Journals (Sweden)

    FATEMEH BAZDID VAHDATI¹,

    2014-11-01

    Full Text Available How plant diversity features change across ecological species groups? A case study of a temperate deciduous forest in northern Iran. Biodiversitas 15: 31-38. Species diversity is one of the most important indices for evaluating the stability and productivity of forest ecosystems. The aim of this research was to recognize ecological species groups and to determine the relationship between environmental variables and the distribution of ecological species groups. For this purpose, 25 400-m2 relevés were sampled using the Braun-Blanquet method. Vegetation was classified using modified Two-Way Indicator Species Analysis (TWINSPAN and resulted in three ecological species groups. Different species diversity indices were applied to quantify diversity of these species groups. ANOVA and Duncan’s tests indicated that all species and environmental variables except altitude changed significantly across the species groups. The results also showed that the group located in the northern aspect and on low slopes had the highest diversity indices compared with groups located in dry aspects and on high slopes. In reality, abundant precipitation (northern aspect ( and soil enrichment (low slopes are principal factors that provide suitable conditions for plant growth and species diversity. Thus, the study of diversity changes in ecological species groups can result in an ecologically precise perspective for managing forest ecosystems.

  8. Factors influencing microhabitat selection and food preference of tree-dwelling earwigs (Dermaptera) in a temperate floodplain forest.

    Science.gov (United States)

    Kirstová, M; Pyszko, P; Kočárek, P

    2018-02-21

    The ecology of earwigs in natural forest ecosystems is poorly understood. We used sweeping to determine the population densities of adult earwigs, by sex and species, on ten tree species in a temperate floodplain forest in southern Moravia (Czech Republic). We also determined the relationships between the properties of tree species and earwig density and diet as indicated by digestive tract contents. The densities and diet composition of earwigs differed between the three detected earwig species [Apterygida media (Hagenbach, 1822), Chelidurella acanthopygia (Genè, 1832) and Forficula auricularia Linnaeus, 1758] and among tree species. Earwig densities were related to lichen coverage and fungal coverage on the trees. The diet of earwigs was associated with specific leaf area, herbivore damage to the leaves, and light exposure of the trees. A. media was the most abundant of the three earwig species. Although the contents of its digestive tract changed depending on available food resources, A. media appeared to preferentially consume soft-bodied insect herbivores and fungi associated with wounds caused by herbivores rather than plant material. Therefore, this species has the potential to help reduce the population densities of soft-bodied pests of forest trees.

  9. Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests.

    Science.gov (United States)

    Du, Yuhan; Guo, Peng; Liu, Jianqiu; Wang, Chunyu; Yang, Ning; Jiao, Zhenxia

    2014-10-01

    Nitrogen (N) deposition significantly affects the soil carbon (C) cycle process of forests. However, the influence of different types of N on it still remained unclear. In this work, ammonium nitrate was selected as an inorganic N (IN) source, while urea and glycine were chosen as organic N (ON) sources. Different ratios of IN to ON (1 : 4, 2 : 3, 3 : 2, 4 : 1, and 5 : 0) were mixed with equal total amounts and then used to fertilize temperate forest soils for 2 years. Results showed that IN deposition inhibited soil C cycle processes, such as soil respiration, soil organic C decomposition, and enzymatic activities, and induced the accumulation of recalcitrant organic C. By contrast, ON deposition promoted these processes. Addition of ON also resulted in accelerated transformation of recalcitrant compounds into labile compounds and increased CO2 efflux. Meanwhile, greater ON deposition may convert C sequestration in forest soils into C source. These results indicated the importance of the IN to ON ratio in controlling the soil C cycle, which can consequently change the ecological effect of N deposition. © 2014 John Wiley & Sons Ltd.

  10. On the vertical distribution of bees in a temperate deciduous forest

    Science.gov (United States)

    Michael Ulyshen; Villa Soon; James Hanula

    2010-01-01

    1. Despite a growing interest in forest canopy biology, very few studies have examined the vertical distribution of forest bees. In this study, bees were sampled using 12 pairs of flight-intercept traps suspended in the canopy (‡15 m) and near the ground (0.5 m) in a bottomland hardwood forest in the southeastern United States. 2. In total, 6653 bees from 5 families...

  11. Effects of climate variability and functional changes on the interannual variation of the carbon balance in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian; van der Linden, Leon; Lasslop, G.

    2012-01-01

    The net ecosystem exchange of CO2 (NEE) between the atmosphere and a temperate beech forest showed a significant interannual variation (IAV) and a decadal trend of increasing carbon uptake (Pilegaard et al., 2011). The objectives of this study were to evaluate to what extent and at which temporal...... scale, direct climatic variability and changes in ecosystem functional properties regulated the IAV of the carbon balance at this site. Correlation analysis showed that the sensitivity of carbon fluxes to climatic variability was significantly higher at shorter than at longer time scales and changed...... seasonally. Ecosystem response anomalies implied that changes in the distribution of climate anomalies during the vegetation period will have stronger impacts on future ecosystem carbon balances than changes in average climate. We improved a published modelling approach which distinguishes the direct...

  12. Internal radiation dose from 137Cs due to the consumption of mushrooms from a Mexican temperate mixed forest

    International Nuclear Information System (INIS)

    Gaso, M.I.; Segovia, N.; Cervantes, M.L.; Herrera, T.; Perez-Silva, E.; Acosta, E.

    2000-01-01

    137 Cs and 40 K specific activities were determined in soil samples and in different edible wild mushroom species collected from a temperate mixed forest located at the Nuclear Centre of Mexico and in several surrounding localities. The activity measurements were performed using HpGe detector. The aggregated transfer factors for 137 Cs in 21 local mushroom species collected from 1993 to 1997, showed differences as large as 3 orders of magnitude. The annual effective dose from 137 Cs due to the consumption of mushrooms was estimated to range between 0.22 and 1.2 μSv.y -1 depending on the method used for calculation. Using the geometric mean of the caesium concentration, the contribution of mushrooms represents 56% of the total 137 Cs dietary intake. (author)

  13. Large-Scale Mixed Temperate Forest Mapping at the Single Tree Level using Airborne Laser Scanning

    Science.gov (United States)

    Scholl, V.; Morsdorf, F.; Ginzler, C.; Schaepman, M. E.

    2017-12-01

    Monitoring vegetation on a single tree level is critical to understand and model a variety of processes, functions, and changes in forest systems. Remote sensing technologies are increasingly utilized to complement and upscale the field-based measurements of forest inventories. Airborne laser scanning (ALS) systems provide valuable information in the vertical dimension for effective vegetation structure mapping. Although many algorithms exist to extract single tree segments from forest scans, they are often tuned to perform well in homogeneous coniferous or deciduous areas and are not successful in mixed forests. Other methods are too computationally expensive to apply operationally. The aim of this study was to develop a single tree detection workflow using leaf-off ALS data for the canton of Aargau in Switzerland. Aargau covers an area of over 1,400km2 and features mixed forests with various development stages and topography. Forest type was classified using random forests to guide local parameter selection. Canopy height model-based treetop maxima were detected and maintained based on the relationship between tree height and window size, used as a proxy to crown diameter. Watershed segmentation was used to generate crown polygons surrounding each maximum. The location, height, and crown dimensions of single trees were derived from the ALS returns within each polygon. Validation was performed through comparison with field measurements and extrapolated estimates from long-term monitoring plots of the Swiss National Forest Inventory within the framework of the Swiss Federal Institute for Forest, Snow, and Landscape Research. This method shows promise for robust, large-scale single tree detection in mixed forests. The single tree data will aid ecological studies as well as forest management practices. Figure description: Height-normalized ALS point cloud data (top) and resulting single tree segments (bottom) on the Laegeren mountain in Switzerland.

  14. Uniform climate sensitivity in tree-ring stable isotopes across species and sites in a mid-latitude temperate forest.

    Science.gov (United States)

    Hartl-Meier, Claudia; Zang, Christian; Büntgen, Ulf; Esper, Jan; Rothe, Andreas; Göttlein, Axel; Dirnböck, Thomas; Treydte, Kerstin

    2015-01-01

    Tree-ring stable isotopes, providing insight into drought-induced eco-physiological mechanisms, are frequently used to reconstruct past changes in growing season temperature and precipitation. Their climatic response is, however, still not fully understood, particularly for data originating from non-extreme, mid-latitude environments with differing ecological conditions. Here, we assess the response of δ(13)C, δ(18)O and tree-ring width (TRW) from a temperate mountain forest in the Austrian pre-Alps to climate and specific drought events. Variations in stem growth and isotopic composition of Norway spruce, common beech and European larch from dry, medium and moist sites are compared with records of sunshine, temperature, moisture, precipitation and cloud cover. Results indicate uniform year-to-year variations in δ(13)C and δ(18)O across sites and species, but distinct differences in TRW according to habitat and species. While the climate sensitivity of TRW is overall weak, the δ(13)C and δ(18)O chronologies contain significant signals with a maximum sensitivity to cloud cover changes (r = -0.72 for δ(18)O). The coherent inter-annual isotopic variations are accompanied by substantial differences in the isotopic signatures with offsets up to ∼3‰ for δ(13)C, indicating species-specific physiological strategies and varying water-use efficiencies. During severe summer drought, beech and larch benefit from access to deeper and moist soils, allowing them to keep their stomata open. This strategy is accompanied by an increased water loss through transpiration, but simultaneously enables enhanced photosynthesis. Our findings indicate the potential of tree-ring stable isotopes from temperate forests to reconstruct changes in cloud cover, and to improve knowledge on basic physiological mechanisms of tree species growing in different habitats to cope with soil moisture deficits. © The Author 2014. Published by Oxford University Press. All rights reserved. For

  15. Tree mortality from fire and bark beetles following early and late season prescribed fires in a Sierra Nevada mixed-conifer forest

    Science.gov (United States)

    Schwilk, Dylan W.; Knapp, Eric E.; Ferrenberg, Scott; Keeley, Jon E.; Caprio, Anthony C.

    2006-01-01

    Over the last century, fire exclusion in the forests of the Sierra Nevada has allowed surface fuels to accumulate and has led to increased tree density. Stand composition has also been altered as shade tolerant tree species crowd out shade intolerant species. To restore forest structure and reduce the risk of large, intense fires, managers have increasingly used prescription burning. Most fires prior to EuroAmerican settlement occurred during the late summer and early fall and most prescribed burning has taken place during the latter part of this period. Poor air quality and lack of suitable burn windows during the fall, however, have resulted in a need to conduct more prescription burning earlier in the season. Previous reports have suggested that burning during the time when trees are actively growing may increase mortality rates due to fine root damage and/or bark beetle activity. This study examines the effects of fire on tree mortality and bark beetle attacks under prescription burning during early and late season. Replicated early season burn, late season burn and unburned control plots were established in an old-growth mixed conifer forest in the Sierra Nevada that had not experienced a fire in over 120 years. Although prescribed burns resulted in significant mortality of particularly the smallest tree size classes, no difference between early and late season burns was detected. Direct mortality due to fire was associated with fire intensity. Secondary mortality due to bark beetles was not significantly correlated with fire intensity. The probability of bark beetle attack on pines did not differ between early and late season burns, while the probability of bark beetle attack on firs was greater following early season burns. Overall tree mortality appeared to be primarily the result of fire intensity rather than tree phenology at the time of the burns. Early season burns are generally conducted under higher fuel moisture conditions, leading to less fuel

  16. 'Natural background' soil water repellency in conifer forests of the north-western USA: Its prediction and relationship to wildfire occurrence

    Science.gov (United States)

    Doerr, S.H.; Woods, S.W.; Martin, D.A.; Casimiro, M.

    2009-01-01

    Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by collecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were further analyzed for repellency using WDPT and contact angle (??sl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelmanii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long-unburnt conifer forest soils of the north-western USA is

  17. Landscape-scale effects of fire severity on mixed-conifer and red fir forest structure in Yosemite National Park

    Science.gov (United States)

    Kane, Van R.; Lutz, James A.; Roberts, Susan L.; Smith, Douglas F.; McGaughey, Robert J.; Povak, Nicholas A.; Brooks, Matthew L.

    2013-01-01

    While fire shapes the structure of forests and acts as a keystone process, the details of how fire modifies forest structure have been difficult to evaluate because of the complexity of interactions between fires and forests. We studied this relationship across 69.2 km2 of Yosemite National Park, USA, that was subject to 32 fires ⩾40 ha between 1984 and 2010. Forests types included ponderosa pine (Pinus ponderosa), white fir-sugar pine (Abies concolor/Pinus lambertiana), and red fir (Abies magnifica). We estimated and stratified burned area by fire severity using the Landsat-derived Relativized differenced Normalized Burn Ratio (RdNBR). Airborne LiDAR data, acquired in July 2010, measured the vertical and horizontal structure of canopy material and landscape patterning of canopy patches and gaps. Increasing fire severity changed structure at the scale of fire severity patches, the arrangement of canopy patches and gaps within fire severity patches, and vertically within tree clumps. Each forest type showed an individual trajectory of structural change with increasing fire severity. As a result, the relationship between estimates of fire severity such as RdNBR and actual changes appears to vary among forest types. We found three arrangements of canopy patches and gaps associated with different fire severities: canopy-gap arrangements in which gaps were enclosed in otherwise continuous canopy (typically unburned and low fire severities); patch-gap arrangements in which tree clumps and gaps alternated and neither dominated (typically moderate fire severity); and open-patch arrangements in which trees were scattered across open areas (typically high fire severity). Compared to stands outside fire perimeters, increasing fire severity generally resulted first in loss of canopy cover in lower height strata and increased number and size of gaps, then in loss of canopy cover in higher height strata, and eventually the transition to open areas with few or no trees. However

  18. How much primary coastal temperate rain forest should society retain? Carbon uptake, recreation and other values

    NARCIS (Netherlands)

    Kooten, van G.C.; Bulte, E.H.

    2000-01-01

    In this study, average and marginal approaches for determining optimal preservation of primary forests on British Columbia's coast are compared. When the market values from timber, mushrooms, etc., and nonmarket benefits (e.g., carbon sink, preservation values) of preserving old-growth forests are

  19. Soil phosphorus fractionation as a tool for monitoring dust phosphorus signature underneath a Blue Pine (Pinus wallichiana canopy in a Temperate Forest

    Directory of Open Access Journals (Sweden)

    Mustafa-Nawaz Shafqat

    2016-12-01

    Full Text Available Aims of the study: This study aims (i to monitor the amount of dust deposition during dry season in the moist temperate forest; (ii to study nature of P fractions in the dust samples falling on the trees in the region; (iii to study soil P fractions as influenced by the processes of throughfall and stemflow of a Blue Pine (Pinus wallichiana canopy and to finger print the contribution of dust towards P input in the temperate forest ecosystem. Area of study: The site used for the collection of soil samples was situated at an elevation of 6900 feet above sea levels (temperate forest in Himalaya region in the Thandani area national forest located in the north west of Pakistan. Material and methods:  For soil sampling and processing, three forest sites with three old tree plants per site were selected at approximately leveled plain for surface soil sampling. Two dust samples were collected and analyzed for different physicochemical properties along with different P fractions. First dust sample was collected from a site situated at an elevation of 4000 feet and second one was collected from an elevation of 6500 feet above sea levels. Modified Hedley procedure for the fractionation of P in the dust and soil samples were used. Main results: The input of dust was 43 and 20 kg ha-1 during drier months of the year (September-June at lower and higher elevation sites respectively, and the dust from lower elevation site had relative more all P fractions than the other dust sample. However, HCl-Pi fraction was dominant in both samples. Both labile (water plus NaHCO3 and non-labile (NaOH plus HCl inorganic P (Pi fractions were significantly increased in the surface soil by both stemflow and throughfall compared to the open field soil. The buildup of NaOH and HCl-Pi pools in soils underneath the canopy might prove useful in fingerprinting the contribution of atmospheric dust towards P cycling in this temperate forest. Research highlights: The role of dust in

  20. Effect of summer throughfall exclusion, summer drought, and winter snow cover on methane fluxes in a temperate forest soil

    Science.gov (United States)

    Borken, W.; Davidson, E.A.; Savage, K.; Sundquist, E.T.; Steudler, P.

    2006-01-01

    Soil moisture strongly controls the uptake of atmospheric methane by limiting the diffusion of methane into the soil, resulting in a negative correlation between soil moisture and methane uptake rates under most non-drought conditions. However, little is known about the effect of water stress on methane uptake in temperate forests during severe droughts. We simulated extreme summer droughts by exclusion of 168 mm (2001) and 344 mm (2002) throughfall using three translucent roofs in a mixed deciduous forest at the Harvard Forest, Massachusetts, USA. The treatment significantly increased CH4 uptake during the first weeks of throughfall exclusion in 2001 and during most of the 2002 treatment period. Low summertime CH4 uptake rates were found only briefly in both control and exclusion plots during a natural late summer drought, when water contents below 0.15 g cm-3 may have caused water stress of methanotrophs in the A horizon. Because these soils are well drained, the exclusion treatment had little effect on A horizon water content between wetting events, and the effect of water stress was smaller and more brief than was the overall treatment effect on methane diffusion. Methane consumption rates were highest in the A horizon and showed a parabolic relationship between gravimetric water content and CH4 consumption, with maximum rate at 0.23 g H2O g-1 soil. On average, about 74% of atmospheric CH4 was consumed in the top 4-5 cm of the mineral soil. By contrast, little or no CH4 consumption occurred in the O horizon. Snow cover significantly reduced the uptake rate from December to March. Removal of snow enhanced CH4 uptake by about 700-1000%, resulting in uptake rates similar to those measured during the growing season. Soil temperatures had little effect on CH4 uptake as long as the mineral soil was not frozen, indicating strong substrate limitation of methanotrophs throughout the year. Our results suggest that the extension of snow periods may affect the annual rate

  1. Predicting temperate forest stand types using only structural profiles from discrete return airborne lidar

    Science.gov (United States)

    Fedrigo, Melissa; Newnham, Glenn J.; Coops, Nicholas C.; Culvenor, Darius S.; Bolton, Douglas K.; Nitschke, Craig R.

    2018-02-01

    Light detection and ranging (lidar) data have been increasingly used for forest classification due to its ability to penetrate the forest canopy and provide detail about the structure of the lower strata. In this study we demonstrate forest classification approaches using airborne lidar data as inputs to random forest and linear unmixing classification algorithms. Our results demonstrated that both random forest and linear unmixing models identified a distribution of rainforest and eucalypt stands that was comparable to existing ecological vegetation class (EVC) maps based primarily on manual interpretation of high resolution aerial imagery. Rainforest stands were also identified in the region that have not previously been identified in the EVC maps. The transition between stand types was better characterised by the random forest modelling approach. In contrast, the linear unmixing model placed greater emphasis on field plots selected as endmembers which may not have captured the variability in stand structure within a single stand type. The random forest model had the highest overall accuracy (84%) and Cohen's kappa coefficient (0.62). However, the classification accuracy was only marginally better than linear unmixing. The random forest model was applied to a region in the Central Highlands of south-eastern Australia to produce maps of stand type probability, including areas of transition (the 'ecotone') between rainforest and eucalypt forest. The resulting map provided a detailed delineation of forest classes, which specifically recognised the coalescing of stand types at the landscape scale. This represents a key step towards mapping the structural and spatial complexity of these ecosystems, which is important for both their management and conservation.

  2. Late Holocene geomorphic record of fire in ponderosa pine and mixed-conifer forests, Kendrick Mountain, northern Arizona, USA

    Science.gov (United States)

    Sara E. Jenkins; Carolyn Hull Sieg; Diana E. Anderson; Darrell S. Kaufman; Philip A. Pearthree

    2011-01-01

    Long-term fire history reconstructions enhance our understanding of fire behaviour and associated geomorphic hazards in forested ecosystems. We used 14C ages on charcoal from fire-induced debris-flow deposits to date prehistoric fires on Kendrick Mountain, northern Arizona, USA. Fire-related debris-flow sedimentation dominates Holocene fan deposition in the study area...

  3. Assessing Surface Fuel Hazard in Coastal Conifer Forests through the Use of LiDAR Remote Sensing

    Science.gov (United States)

    Koulas, Christos

    The research problem that this thesis seeks to examine is a method of predicting conventional fire hazards using data drawn from specific regions, namely the Sooke and Goldstream watershed regions in coastal British Columbia. This thesis investigates whether LiDAR data can be used to describe conventional forest stand fire hazard classes. Three objectives guided this thesis: to discuss the variables associated with fire hazard, specifically the distribution and makeup of fuel; to examine the relationship between derived LiDAR biometrics and forest attributes related to hazard assessment factors defined by the Capitol Regional District (CRD); and to assess the viability of the LiDAR biometric decision tree in the CRD based on current frameworks for use. The research method uses quantitative datasets to assess the optimal generalization of these types of fire hazard data through discriminant analysis. Findings illustrate significant LiDAR-derived data limitations, and reflect the literature in that flawed field application of data modelling techniques has led to a disconnect between the ways in which fire hazard models have been intended to be used by scholars and the ways in which they are used by those tasked with prevention of forest fires. It can be concluded that a significant trade-off exists between computational requirements for wildfire simulation models and the algorithms commonly used by field teams to apply these models with remote sensing data, and that CRD forest management practices would need to change to incorporate a decision tree model in order to decrease risk.

  4. Shrub seed banks in mixed conifer forests of northern California and the role of fire in regulating abundance

    Science.gov (United States)

    Eric E. Knapp; Phillip C. Weatherspoon; Carl N. Skinner

    2012-01-01

    Understory shrubs play important ecological roles in forests of the western US, but they can also impede early tree growth and lead to fire hazard concerns when very dense. Some of the more common genera (Ceanothus, Arctostaphylos, and Prunus) persist for long periods in the seed bank, even in areas where plants have been...

  5. Relating fuel loads to overstorey structure and composition in a fire-excluded Sierra Nevada mixed conifer forest

    Science.gov (United States)

    Jamie M. Lydersen; Brandon M. Collins; Eric E. Knapp; Gary B. Roller; Scott Stephens

    2015-01-01

    Although knowledge of surface fuel loads is critical for evaluating potential fire behaviour and effects, their inherent variability makes these difficult to quantify. Several studies relate fuel loads to vegetation type, topography and spectral imaging, but little work has been done examining relationships between forest overstorey variables and surface fuel...

  6. Individual tree detection from Unmanned Aerial Vehicle (UAV) derived canopy height model in an open canopy mixed conifer forest

    Science.gov (United States)

    Midhun Mohan; Carlos Alberto Silva; Carine Klauberg; Prahlad Jat; Glenn Catts; Adrian Cardil; Andrew Thomas Hudak; Mahendra Dia

    2017-01-01

    Advances in Unmanned Aerial Vehicle (UAV) technology and data processing capabilities have made it feasible to obtain high-resolution imagery and three dimensional (3D) data which can be used for forest monitoring and assessing tree attributes. This study evaluates the applicability of low consumer grade cameras attached to UAVs and structure-from-motion (SfM)...

  7. Some comments on the ‘Moist temperate forest butterflies of western Bhutan’

    Czech Academy of Sciences Publication Activity Database

    Irungbam, Jatishwor

    2016-01-01

    Roč. 8, č. 5 (2016), s. 8846-8848 ISSN 0974-7893 Institutional support: RVO:60077344 Keywords : forest butterflies * western Bhutan * comments Subject RIV: EG - Zoology http://threatenedtaxa.org/index.php/JoTT/article/view/2709

  8. Ecological indicators of Tuber aestivum habitats in temperate European beech forests

    Czech Academy of Sciences Publication Activity Database

    Moser, B.; Büntgen, Ulf; Molinier, V.; Peter, M.; Sproll, L.; Stobbe, U.; Tegel, W.; Egli, S.

    2017-01-01

    Roč. 29, oct (2017), s. 59-66 ISSN 1754-5048 R&D Projects: GA MŠk(CZ) EE2.3.20.0248 Institutional support: RVO:67179843 Keywords : Burgundy truffle * Carpinus betulus forest * Ecological indicator values * Fagus sylvatica forest * Potential distribution of Tuber aestivum * Truffle ecology Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 3.219, year: 2016

  9. The bacterial community inhabiting temperate deciduous forests is vertically stratified and undergoes seasonal dynamics

    Czech Academy of Sciences Publication Activity Database

    López-Mondéjar, Rubén; Voříšková, Jana; Větrovský, Tomáš; Baldrian, Petr

    2015-01-01

    Roč. 87, č. 1 (2015), s. 43-50 ISSN 0038-0717 R&D Projects: GA MŠk(CZ) EE2.3.30.0003; GA MŠk(CZ) ED1.1.00/02.0109; GA MŠk LD12048; GA MŠk LD12050 Institutional support: RVO:61388971 Keywords : Bacterial community * Deciduous forest * Forest soil Subject RIV: EE - Microbiology, Virology Impact factor: 4.152, year: 2015

  10. Repeated prescribed fires decrease stocks and change attributes of coarse woody debris in a temperate eucalypt forest.

    Science.gov (United States)

    Aponte, Cristina; Tolhurst, Kevin G; Bennett, Lauren T

    2014-07-01

    Previous studies have found negligible effects of single prescribed fires on coarse woody debris (CWD), but the cumulative effects of repeated low-intensity prescribed fires are unknown. This represents a knowledge gap for environmental management because repeated prescribed fires are a key tool for mitigating wildfire risk, and because CWD is recognized as critical to forest biodiversity and functioning. We examined the effects of repeated low-intensity prescribed fires on the attributes and stocks of (fallen) CWD in a mixed-species eucalypt forest of temperate Australia. Prescribed fire treatments were a factorial combination of two seasons (Autumn, Spring) and two frequencies (three yearly High, 10 yearly Low), were replicated over five study areas, and involved two to seven low-intensity fires over 27 years. Charring due to prescribed fires variously changed carbon and nitrogen concentrations and C to N ratios of CWD pieces depending on decay class, but did not affect mean wood density. CWD biomass and C and N stocks were significantly less in Fire than Control treatments. Decreases in total CWD C stocks of -8 Mg/ha in Fire treatments were not balanced by minor increases in pyrogenic (char) C (-0.3 Mg/ha). Effects of prescribed fire frequency and season included significantly less C and N stocks in rotten CWD in High than Low frequency treatments, and in the largest CWD pieces in Autumn than Spring treatments. Our study demonstrates that repeated low-intensity prescribed fires have the potential to significantly decrease CWD stocks, in pieces of all sizes and particularly decayed pieces, and to change CWD chemical attributes. CWD is at best a minor stock of pyrogenic C under such fire regimes. These findings suggest a potential trade-off in the management of temperate eucalypt forests between sustained reduction of wildfire risk, and the consequences of decreased CWD C stocks, and of changes in CWD as a habitat and biogeochemical substrate. Nonetheless

  11. Effects of forest fragmentation on the mating system of a cool-temperate heterodichogamous tree Acer mono

    Directory of Open Access Journals (Sweden)

    Satoshi Kikuchi

    2015-01-01

    Full Text Available Pollination is a key process for reproduction and gene flow in flowering plants. Anthropogenic habitat fragmentation, however, can disrupt plant–pollinator interactions, and may have a negative impact on the reproductive success and population viability of entomophilous plants. Heterodichogamous plants containing protandrous and protogynous individuals within a population may be susceptible to habitat fragmentation due to a lack of available mating partners. In this study, we investigated the effects of forest fragmentation on the mating system in the heterodichogamous plant Acer mono, a major constituent of cool-temperate deciduous forests in Japan. Microsatellite analysis was applied to 212 adult trees and 17 seed families from continuous and fragmented forests. Dispersal kernel modeling using the neighborhood model indicated that pollen dispersal of A. mono was highly fat-tailed. The estimated parameters of the model suggested that the siring success of a pollen donor increased approximately fivefold, with a 100 cm increase in its diameter at breast height (DBH, and that disassortative mating was five times more frequent than assortative mating. The mating system parameters of each mother tree, outcrossing rate (tm, biparental inbreeding (tm−ts, and paternity correlation (rpm varied among sites and conditions, depending on the local density of potential pollen donors. Whereas A. mono was effectively outcrossed (tm=0.901, tm−ts=0.052, and the number of effective sires was 1/rpm=14.93 in the continuous forest, clumped trees within the fragmented forest showed increased biparental inbreeding and reduced pollen pool genetic diversity (tm=0.959, tm−ts=0.245,1/rpm=1.742 as a result of localized mating combined with spatial genetic structures. In contrast, the isolated trees had a higher selfing rate, but the pollen pool diversity was maintained (tm=0.801, tm−ts=0.022, and 1/rpm=15.63 due to frequent long-distance pollination. These

  12. Optimizing variable radius plot size and LiDAR resolution to model standing volume in conifer forests

    Science.gov (United States)

    Ram Kumar Deo; Robert E. Froese; Michael J. Falkowski; Andrew T. Hudak

    2016-01-01

    The conventional approach to LiDAR-based forest inventory modeling depends on field sample data from fixed-radius plots (FRP). Because FRP sampling is cost intensive, combining variable-radius plot (VRP) sampling and LiDAR data has the potential to improve inventory efficiency. The overarching goal of this study was to evaluate the integration of LiDAR and VRP data....

  13. The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, USA

    Science.gov (United States)

    Fraver, S.; Jain, T.; Bradford, J.B.; D'Amato, A.W.; Kastendick, D.; Palik, B.; Shinneman, D.; Stanovick, J.

    2011-01-01

    Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances-blowdown, salvage logging, and ildfire- provided an excellent opportunity to assess the impacts of blowdown and salvage logging on wildfire severity. We used two fire-severity assessments (tree-crown and forest-floor characteristics) to compare post-wildfire conditions among three treatment combinations (Blowdown-Salvage-Fire, Blowdown-Fire, and Fire only). Our results suggest that salvage logging reduced the intensity (heat released) of the subsequent fire. However, its effect on severity (impact to the system) differed between the tree crowns and forest floor: tree-crown indices suggest that salvage logging decreased fire severity (albeit with modest statistical support), while forest-floor indices suggest that salvage logging increased fire severity. We attribute the latter finding to the greater exposure of mineral soil caused by logging operations; once exposed, soils are more likely to register the damaging effects of fire, even if fire intensity is not extreme. These results highlight the important distinction between fire intensity and severity when formulating post-disturbance management prescriptions. ?? 2011 by the Ecological Society of America.

  14. Soil-water content characterisation in a modified Jarvis-Stewart model: A case study of a conifer forest on a shallow unconfined aquifer

    Science.gov (United States)

    Guyot, Adrien; Fan, Junliang; Oestergaard, Kasper T.; Whitley, Rhys; Gibbes, Badin; Arsac, Margaux; Lockington, David A.

    2017-01-01

    Groundwater-vegetation-atmosphere fluxes were monitored for a subtropical coastal conifer forest in South-East Queensland, Australia. Observations were used to quantify seasonal changes in transpiration rates with respect to temporal fluctuations of the local water table depth. The applicability of a Modified Jarvis-Stewart transpiration model (MJS), which requires soil-water content data, was assessed for this system. The influence of single depth values compared to use of vertically averaged soil-water content data on MJS-modelled transpiration was assessed over both a wet and a dry season, where the water table depth varied from the surface to a depth of 1.4 m below the surface. Data for tree transpiration rates relative to water table depth showed that trees transpire when the water table was above a threshold depth of 0.8 m below the ground surface (water availability is non-limiting). When the water table reached the ground surface (i.e., surface flooding) transpiration was found to be limited. When the water table is below this threshold depth, a linear relationship between water table depth and the transpiration rate was observed. MJS modelling results show that the influence of different choices for soil-water content on transpiration predictions was insignificant in the wet season. However, during the dry season, inclusion of deeper soil-water content data improved the model performance (except for days after isolated rainfall events, here a shallower soil-water representation was better). This study demonstrated that, to improve MJS simulation results, appropriate selection of soil water measurement depths based on the dynamic behaviour of soil water profiles through the root zone was required in a shallow unconfined aquifer system.

  15. Quantifying resilience of multiple ecosystem services and biodiversity in a temperate forest landscape.

    Science.gov (United States)

    Cantarello, Elena; Newton, Adrian C; Martin, Philip A; Evans, Paul M; Gosal, Arjan; Lucash, Melissa S

    2017-11-01

    Resilience is increasingly being considered as a new paradigm of forest management among scientists, practitioners, and policymakers. However, metrics of resilience to environmental change are lacking. Faced with novel disturbances, forests may be able to sustain existing ecosystem services and biodiversity by exhibiting resilience, or alternatively these attributes may undergo either a linear or nonlinear decline. Here we provide a novel quantitative approach for assessing forest resilience that focuses on three components of resilience, namely resistance, recovery, and net change, using a spatially explicit model of forest dynamics. Under the pulse set scenarios, we explored the resilience of nine ecosystem services and four biodiversity measures following a one-off disturbance applied to an increasing percentage of forest area. Under the pulse + press set scenarios, the six disturbance intensities explored during the pulse set were followed by a continuous disturbance. We detected thresholds in net change under pulse + press scenarios for the majority of the ecosystem services and biodiversity measures, which started to decline sharply when disturbance affected >40% of the landscape. Thresholds in net change were not observed under the pulse scenarios, with the exception of timber volume and ground flora species richness. Thresholds were most pronounced for aboveground biomass, timber volume with respect to the ecosystem services, and ectomycorrhizal fungi and ground flora species richness with respect to the biodiversity measures. Synthesis and applications . The approach presented here illustrates how the multidimensionality of stability research in ecology can be addressed and how forest resilience can be estimated in practice. Managers should adopt specific management actions to support each of the three components of resilience separately, as these may respond differently to disturbance. In addition, management interventions aiming to deliver resilience

  16. Drought during canopy development has lasting effect on annual carbon balance in a deciduous temperate forest

    Science.gov (United States)

    Asko Noormets; Steve G. McNulty; Jared L. DeForest; Ge Sun; Qinglin Li; Jiquan Chen

    2008-01-01

    Climate change projections predict an intensifying hydrologic cycle and an increasing frequency of droughts, yet quantitative understanding of the effects on ecosystem carbon exchange remains limitedHere, the effect of contrasting precipitation and soil moisture dynamics were evaluated on forest carbon exchange using 2 yr of...

  17. Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests

    Czech Academy of Sciences Publication Activity Database

    Verheyen, E.; Baeten, L.; De Frenne, P.; Brnhardt-Römermann, M.; Brunet, J.; Cornelis, J.; Decocq, G.; Dierschke, H.; Eriksson, O.; Hédl, Radim; Heinken, T.; Hermy, M.; Hommel, P.; Kirby, K.; Naaf, T.; Peterken, G.; Petřík, Petr; Pfadenhauer, J.; Van Calster, H.; Walther, G.-R.; Wulf, M.; Verstraeten, G.

    2012-01-01

    Roč. 100, č. 2 (2012), s. 352-365 ISSN 0022-0477 R&D Projects: GA AV ČR IAA600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : Ellenberg indicator values * forest management * large herbivores Subject RIV: EF - Botanics Impact factor: 5.431, year: 2012

  18. Assessment of trends in predation pressure on insects across temperate forest microhabitats

    Czech Academy of Sciences Publication Activity Database

    Šipoš, Jan; Drozdová, M.; Drozd, P.

    2013-01-01

    Roč. 15, č. 3 (2013), s. 255-261 ISSN 1461-9555 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0073; GA MŠk LC06073 Institutional support: RVO:67179843 Keywords : forest layers * predation rate * refuge * spatial variability * temporal variability Subject RIV: EH - Ecology, Behaviour Impact factor: 1.556, year: 2013

  19. CO2 balance of boreal, temperate, and tropical forests derived from a global database

    NARCIS (Netherlands)

    Luyssaert, S.; Inglima, I.; Jung, M.; Richardson, A.D.; Reichstein, M.; Papale, D.; Piao, S.L.; Schulze, E.D.; Wingate, L.; Matteucci, G.; Aragao, L.; Aubinet, M.; Beer, C.; Bernhofer, C.; Black, K.G.; Bonal, D.; Bonnefond, J.M.; Chambers, J.; Ciais, P.; Cook, B.; Davis, K.J.; Dolman, A.J.; Gielen, B.; Goulden, M.; Grace, J.; Granier, A.; Grelle, A.; Griffis, T.; Gruenwald, T.; Guidolotti, G.; Hanson, P.J.; Harding, R.; Hollinger, D.Y.; Hutyra, L.R.; Kolari, P.; Kruijt, B.; Kutsch, W.; Lagergren, F.; Laurila, T.

    2007-01-01

    Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount of the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding the fate of this carbon over both short and long timescales. Relevant data to address these uncertainties are

  20. Net primary production of a temperate deciduous forest exhibits a threshold response to increasing disturbance severity.

    Science.gov (United States)

    Stuart-Haëntjens, Ellen J; Curtis, Peter S; Fahey, Robert T; Vogel, Christoph S; Gough, Christopher M

    2015-09-01

    The global carbon (C) balance is vulnerable to disturbances that alter terrestrial C storage. Disturbances to forests occur along a continuum of severity, from low-intensity disturbance causing the mortality or defoliation of only a subset of trees to severe stand- replacing disturbance that kills all trees; yet considerable uncertainty remains in how forest production changes across gradients of disturbance intensity. We used a gradient of tree mortality in an upper Great Lakes forest ecosystem to: (1) quantify how aboveground wood net primary production (ANPP,) responds to a range of disturbance severities; and (2) identify mechanisms supporting ANPPw resistance or resilience following moderate disturbance. We found that ANPPw declined nonlinearly with rising disturbance severity, remaining stable until >60% of the total tree basal area senesced. As upper canopy openness increased from disturbance, greater light availability to the subcanopy enhanced the leaf-level photosynthesis and growth of this formerly light-limited canopy stratum, compensating for upper canopy production losses and a reduction in total leaf area index (LAI). As a result, whole-ecosystem production efficiency (ANPPw/LAI) increased with rising disturbance severity, except in plots beyond the disturbance threshold. These findings provide a mechanistic explanation for a nonlinear relationship between ANPPw, and disturbance severity, in which the physiological and growth enhancement of undisturbed vegetation is proportional to the level of disturbance until a threshold is exceeded. Our results have important ecological and management implications, demonstrating that in some ecosystems moderate levels of disturbance minimally alter forest production.

  1. Seasonal dynamics of fungal communities in a temperate oak forest soil

    Czech Academy of Sciences Publication Activity Database

    Voříšková, Jana; Brabcová, Vendula; Cajthaml, Tomáš; Baldrian, Petr

    2014-01-01

    Roč. 201, č. 1 (2014), s. 269-278 ISSN 1469-8137 R&D Projects: GA ČR GAP504/12/0709 Institutional support: RVO:61388971 Keywords : fungi * forest * communities Subject RIV: EE - Microbiology , Virology Impact factor: 6.545, year: 2013

  2. Nitrogen fertilization interacts with light to increase Rubus spp. cover in a temperate forest

    Science.gov (United States)

    Christopher A. Walter; Devon T. Raiff; Mark B. Burnham; Frank S. Gilliam; Mary Beth Adams; William T. Peterjohn

    2016-01-01

    Nitrogen additions have caused species composition changes in many ecosystems by facilitating the growth of nitrophilic species. After 24 years of nitrogen fertilization in a 40 year-old stand at the Fernow Experimental Forest (FEF) in Central Appalachia, USA, the cover of Rubus spp. has increased from 1 to 19 % of total herbaceous-layer cover....

  3. What cues do ungulates use to assess predation risk in dense temperate forests?

    NARCIS (Netherlands)

    Kuijper, Dries P.J.; Verwijmeren, Mart; Churski, Marcin; Zbyryt, Adam; Schmidt, Krzysztof; Jędrzejewska, Bogumiła; Smit, Chris

    2014-01-01

    Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in

  4. Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests

    NARCIS (Netherlands)

    Verheyen, K.; Baeten, L.; Frenne, De P.; Bernhardt-Römermann, M.; Brunet, J.; Cornelis, J.; Decocq, G.; Eriksson, O.; Dierschke, H.; Hommel, P.W.F.M.

    2012-01-01

    1. Atmospheric nitrogen (N) deposition is expected to change forest understorey plant community composition and diversity, but results of experimental addition studies and observational studies are not yet conclusive. A shortcoming of observational studies, which are generally based on resurveys or

  5. Contrasting patterns of fine-scale herb layer species composition in temperate forests

    Czech Academy of Sciences Publication Activity Database

    Chudomelová, Markéta; Zelený, D.; Li, C.-F.

    2017-01-01

    Roč. 80, APR 2017 (2017), s. 24-31 ISSN 1146-609X Institutional support: RVO:67985939 Keywords : spatial structures * environmental heterogenity * oak forest Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 1.652, year: 2016

  6. What Cues Do Ungulates Use to Assess Predation Risk in Dense Temperate Forests?

    NARCIS (Netherlands)

    Kuijper, D.P.J.; Verwijmeren, M.; Churski, M.; Zbyryt, A.; Schmidt, K.; Jedrzejewska, B.; Smit, C.

    2014-01-01

    Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in

  7. The demographics and regeneration dynamic of hickory in second-growth temperate forest

    Science.gov (United States)

    Aaron B. Lefland; Marlyse C. Duguid; Randall S. Morin; Mark S. Ashton

    2018-01-01

    Hickory (Carya spp.) is an economically and ecologically important genus to the eastern deciduous forest of North America. Yet, much of our knowledge about the genus comes from observational and anecdotal studies that examine the genus as a whole, or from research that examines only one species, in only one part of its range. Here, we use data sets...

  8. Vulnerability and Resilience of Temperate Forest Landscapes to Broad-Scale Deforestation in Response to Changing Fire Regimes and Altered Post-Fire Vegetation Dynamics

    Science.gov (United States)

    Tepley, A. J.; Veblen, T. T.; Perry, G.; Anderson-Teixeira, K. J.

    2015-12-01

    In the face of on-going climatic warming and land-use change, there is growing concern that temperate forest landscapes could be near a tipping point where relatively small changes to the fire regime or altered post-fire vegetation dynamics could lead to extensive conversion to shrublands or savannas. To evaluate vulnerability and resilience to such conversion, we develop a simple model based on three factors we hypothesize to be key in predicting temperate forest responses to changing fire regimes: (1) the hazard rate (i.e., the probability of burning in the next year given the time since the last fire) in closed-canopy forests, (2) the hazard rate for recently-burned, open-canopy vegetation, and (3) the time to redevelop canopy closure following fire. We generate a response surface representing the proportions of the landscape potentially supporting closed-canopy forest and non-forest vegetation under nearly all combinations of these three factors. We then place real landscapes on this response surface to assess the type and magnitude of changes to the fire regime that would drive extensive forest loss. We show that the deforestation of much of New Zealand that followed initial human colonization and the introduction of a new ignition source ca. 750 years ago was essentially inevitable due to the slow rate of forest recovery after fire and the high flammability of post-fire vegetation. In North America's Pacific Northwest, by contrast, a predominantly forested landscape persisted despite two periods of widespread burning in the recent past due in large part to faster post-fire forest recovery and less pronounced differences in flammability between forests and the post-fire vegetation. We also assess the factors that could drive extensive deforestation in other regions to identify where management could reduce this potential and to guide field and modeling work to better understand the responses and ecological feedbacks to changing fire regimes.

  9. Quantifying Tree and Soil Carbon Stocks in a Temperate Urban Forest in Northeast China

    Directory of Open Access Journals (Sweden)

    Hailiang Lv

    2016-09-01

    Full Text Available Society has placed greater focus on the ecological service of urban forests; however, more information is required on the variation of carbon (C in trees and soils in different functional forest types, administrative districts, and urban-rural gradients. To address this issue, we measured various tree and soil parameters by sampling 219 plots in the urban forest of the Harbin city region. Averaged tree and soil C stock density (C stocks per unit tree cover for Harbin city were 7.71 (±7.69 kg C·m−2 and 5.48 (±2.86 kg C·m−2, respectively. They were higher than those of other Chinese cities (Shenyang and Changchun, but were much lower than local natural forests. The tree C stock densities varied 2.3- to 3.2-fold among forest types, administrative districts, and ring road-based urban-rural gradients. In comparison, soil organic C (SOC densities varied by much less (1.4–1.5-fold. We found these to be urbanization-dependent processes, which were closely related to the urban-rural gradient data based on ring-roads and settlement history patterns. We estimated that SOC accumulation during the 100-year urbanization of Harbin was very large (5 to 14 thousand tons, accounting for over one quarter of the stored C in trees. Our results provide new insights into the dynamics of above- and below-ground C (especially in soil during the urbanization process, and that a city’s ability to provide C-related ecosystem services increases as it ages. Our findings highlight that urbanization effects should be incorporated into calculations of soil C budgets in regions subject to rapid urban expansion, such as China.

  10. An assessment of ectomycorrhizal fungal communities in Tasmanian temperate high-altitude Eucalyptus delegatensis forest reveals a dominance of the Cortinariaceae.

    Science.gov (United States)

    Horton, Bryony M; Glen, Morag; Davidson, Neil J; Ratkowsky, David A; Close, Dugald C; Wardlaw, Tim J; Mohammed, Caroline

    2017-01-01

    Fungal diversity of Australian eucalypt forests remains underexplored. We investigated the ectomycorrhizal (EcM) fungal community characteristics of declining temperate eucalypt forests in Tasmania. Within this context, we explored the diversity of EcM fungi of two forest types in the northern highlands in the east and west of the island. We hypothesised that EcM fungal community richness and composition would differ between forest type but that the Cortinariaceae would be the dominant family irrespective of forest type. We proposed that EcM richness would be greater in the wet sclerophyll forest than the dry sclerophyll forest type. Using both sporocarps and EcM fungi from root tips amplified by PCR and sequenced in the rDNA ITS region, 175 EcM operational taxonomic units were identified of which 97 belonged to the Cortinariaceae. The Cortinariaceae were the most diverse family, in both the above and below ground communities. Three distinct fungal assemblages occurred within the wet and dry sclerophyll forest types and two geographic regions that were studied, although this pattern did not remain when only the root tip data were analysed. EcM sporocarp richness was unusually higher than root tip richness and EcM richness did not significantly differ among forest types. The results are discussed in relation to the importance of the Cortinariaceae and the drivers of EcM fungal community composition within these forests.

  11. Changes in conifer and deciduous forest foliar and forest floor chemistry and basal area tree growth across a nitrogen (N) deposition gradient in the northeastern US

    Science.gov (United States)

    Johnny L. Boggs; Steven G. McNulty; Linda H. Pardo

    2007-01-01

    We evaluated foliar and forest floor chemistry across a gradient of N deposition in the Northeast at 11 red spruce (Picea rubens Sarg.) sites in 1987/1988 and foliar and forest floor chemistry and basal area growth at six paired spruce and deciduous sites in 1999. The six red spruce plots were a subset of the original 1987/1988 spruce sites. In 1999...

  12. Nitrous oxide and methane exchange in two small temperate forest catchments - effects of hydrological gradients and implications for global warming potentials of forest soils

    DEFF Research Database (Denmark)

    Christiansen, Jesper Riis; Vesterdal, Lars; Gundersen, Per

    2012-01-01

    The magnitude of greenhouse gas (GHG) flux rates may be important in wet and intermediate wet forest soils, but published estimates are scarce. We studied the surface exchange of methane (CH4) and nitrous oxide (N2O) from soil along toposequences in two temperate deciduous forest catchments......: Strødam and Vestskoven. The soil water regime ranged from fully saturated to aerated within the catchments. At Strødam the largest mean flux rates of N2O (15 µg N2O-N m-2 h-1) were measured at volumetric soil water contents (SWC) between 40 and 60% and associated with low soil pH compared to smaller mean...... flux rates of 0-5 µg N2O-N m-2 h-1 for drier (SWC 80%). At Vestskoven the same response of N2O to soil water content was observed. Average CH4 flux rates were highly variable along the toposequences (-17 to 536 µg CH4-C m-2 h-1) but emissions were only observed above...

  13. The Legacy of Episodic Climatic Events in Shaping Temperate, Broadleaf Forests

    Science.gov (United States)

    Pederson, Neil; Dyer, James M.; McEwan, Ryan W.; Hessl, Amy E.; Mock, Cary J.; Orwig, David A.; Rieder, Harald E.; Cook, Benjamin I.

    2015-01-01

    In humid, broadleaf-dominated forests where gap dynamics and partial canopy mortality appears to dominate the disturbance regime at local scales, paleoecological evidence shows alteration at regional-scales associated with climatic change. Yet, little evidence of these broad-scale events exists in extant forests. To evaluate the potential for the occurrence of large-scale disturbance, we used 76 tree-ring collections spanning approx. 840 000 sq km and 5327 tree recruitment dates spanning approx. 1.4 million sq km across the humid eastern United States. Rotated principal component analysis indicated a common growth pattern of a simultaneous reduction in competition in 22 populations across 61 000 km2. Growth-release analysis of these populations reveals an intense and coherent canopy disturbance from 1775 to 1780, peaking in 1776. The resulting time series of canopy disturbance is so poorly described by a Gaussian distribution that it can be described as ''heavy tailed,'' with most of the years from 1775 to 1780 comprising the heavy-tail portion of the distribution. Historical documents provide no evidence that hurricanes or ice storms triggered the 1775-1780 event. Instead, we identify a significant relationship between prior drought and years with elevated rates of disturbance with an intense drought occurring from 1772 to 1775. We further find that years with high rates of canopy disturbance have a propensity to create larger canopy gaps indicating repeated opportunities for rapid change in species composition beyond the landscape scale. Evidence of elevated, regional-scale disturbance reveals how rare events can potentially alter system trajectory: a substantial portion of old-growth forests examined here originated or were substantially altered more than two centuries ago following events lasting just a few years. Our recruitment data, comprised of at least 21 species and several shade-intolerant species, document a pulse of tree recruitment at the

  14. Effects of forest management practices in temperate beech forests on bacterial and fungal communities involved in leaf litter degradation.

    Science.gov (United States)

    Purahong, Witoon; Kapturska, Danuta; Pecyna, Marek J; Jariyavidyanont, Katalee; Kaunzner, Jennifer; Juncheed, Kantida; Uengwetwanit, Tanaporn; Rudloff, Renate; Schulz, Elke; Hofrichter, Martin; Schloter, Michael; Krüger, Dirk; Buscot, François

    2015-05-01

    Forest management practices (FMPs) significantly influence important ecological processes and services in Central European forests, such as leaf litter decomposition and nutrient cycling. Changes in leaf litter diversity, and thus, its quality as well as microbial community structure and function induced by different FMPs were hypothesized to be the main drivers causing shifts in decomposition rates and nutrient release in managed forests. In a litterbag experiment lasting 473 days, we aimed to investigate the effects of FMPs (even-aged timber management, selective logging and unmanaged) on bacterial and fungal communities involved in leaf litter degradation over time. Our results showed that microbial communities in leaf litter were strongly influenced by both FMPs and sampling date. The results from nonmetric multidimensional scaling (NMDS) ordination revealed distinct patterns of bacterial and fungal successions over time in leaf litter. We demonstrated that FMPs and sampling dates can influence a range of factors, including leaf litter quality, microbial macronutrients, and pH, which significantly correlate with microbial community successions.

  15. Linking root traits to nutrient foraging in arbuscular mycorrhizal trees in a temperate forest.

    Science.gov (United States)

    Eissenstat, David M; Kucharski, Joshua M; Zadworny, Marcin; Adams, Thomas S; Koide, Roger T

    2015-10-01

    The identification of plant functional traits that can be linked to ecosystem processes is of wide interest, especially for predicting vegetational responses to climate change. Root diameter of the finest absorptive roots may be one plant trait that has wide significance. Do species with relatively thick absorptive roots forage in nutrient-rich patches differently from species with relatively fine absorptive roots? We measured traits related to nutrient foraging (root morphology and architecture, root proliferation, and mycorrhizal colonization) across six coexisting arbuscular mycorrhizal (AM) temperate tree species with and without nutrient addition. Root traits such as root diameter and specific root length were highly correlated with root branching intensity, with thin-root species having higher branching intensity than thick-root species. In both fertilized and unfertilized soil, species with thin absorptive roots and high branching intensity showed much greater root length and mass proliferation but lower mycorrhizal colonization than species with thick absorptive roots. Across all species, fertilization led to increased root proliferation and reduced mycorrhizal colonization. These results suggest that thin-root species forage more by root proliferation, whereas thick-root species forage more by mycorrhizal fungi. In mineral nutrient-rich patches, AM trees seem to forage more by proliferating roots than by mycorrhizal fungi. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  16. Multiple metrics of diversity have different effects on temperate forest functioning over succession.

    OpenAIRE

    Yuan, Zuoqiang; Wang, Shaopeng; Gazol, Antonio; Mellard, Jarad Pope; Lin, Fei; Ye, Ji; Hao, Zhanqing; Wang, Xugao; Loreau, Michel

    2016-01-01

    Biodiversity can be measured by taxonomic, phylogenetic, and functional diversity. How ecosystem functioning depends on these measures of diversity can vary from site to site and depends on successional stage. Here, we measured taxonomic, phylogenetic, and functional diversity, and examined their relationship with biomass in two successional stages of the broad-leaved Korean pine forest in northeastern China. Functional diversity was calculated from six plant traits, and aboveground biomass (...

  17. What cues do ungulates use to assess predation risk in dense temperate forests?

    Science.gov (United States)

    Kuijper, Dries P J; Verwijmeren, Mart; Churski, Marcin; Zbyryt, Adam; Schmidt, Krzysztof; Jędrzejewska, Bogumiła; Smit, Chris

    2014-01-01

    Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in the Białowieża Primeval Forest (Poland), whether perceived predation risk in red deer (Cervus elaphus) and wild boar (Sus scrofa) is related to habitat visibility or olfactory cues of a predator. We used camera traps in two different set-ups to record undisturbed ungulate behavior and fresh wolf (Canis lupus) scats as olfactory cue. Habitat visibility at fixed locations in deciduous old growth forest affected neither vigilance levels nor visitation rate and cumulative visitation time of both ungulate species. However, red deer showed a more than two-fold increase of vigilance level from 22% of the time present on control plots to 46% on experimental plots containing one wolf scat. Higher vigilance came at the expense of time spent foraging, which decreased from 32% to 12% while exposed to the wolf scat. These behavioral changes were most pronounced during the first week of the experiment but continuous monitoring of the plots suggested that they might last for several weeks. Wild boar did not show behavioral responses indicating higher perceived predation risk. Visitation rate and cumulative visitation time were not affected by the presence of a wolf scat in both ungulate species. The current study showed that perceived predation risk in red deer and wild boar is not related to habitat visibility in a dense forest ecosystem. However, olfactory cues of wolves affected foraging behavior of their preferred prey species red deer. We showed that odor of wolves in an ecologically equivalent dose is sufficient to create fine-scale risk factors for red deer.

  18. What cues do ungulates use to assess predation risk in dense temperate forests?

    Directory of Open Access Journals (Sweden)

    Dries P J Kuijper

    Full Text Available Anti-predator responses by ungulates can be based on habitat features or on the near-imminent threat of predators. In dense forest, cues that ungulates use to assess predation risk likely differ from half-open landscapes, as scent relative to sight is predicted to be more important. We studied, in the Białowieża Primeval Forest (Poland, whether perceived predation risk in red deer (Cervus elaphus and wild boar (Sus scrofa is related to habitat visibility or olfactory cues of a predator. We used camera traps in two different set-ups to record undisturbed ungulate behavior and fresh wolf (Canis lupus scats as olfactory cue. Habitat visibility at fixed locations in deciduous old growth forest affected neither vigilance levels nor visitation rate and cumulative visitation time of both ungulate species. However, red deer showed a more than two-fold increase of vigilance level from 22% of the time present on control plots to 46% on experimental plots containing one wolf scat. Higher vigilance came at the expense of time spent foraging, which decreased from 32% to 12% while exposed to the wolf scat. These behavioral changes were most pronounced during the first week of the experiment but continuous monitoring of the plots suggested that they might last for several weeks. Wild boar did not show behavioral responses indicating higher perceived predation risk. Visitation rate and cumulative visitation time were not affected by the presence of a wolf scat in both ungulate species. The current study showed that perceived predation risk in red deer and wild boar is not related to habitat visibility in a dense forest ecosystem. However, olfactory cues of wolves affected foraging behavior of their preferred prey species red deer. We showed that odor of wolves in an ecologically equivalent dose is sufficient to create fine-scale risk factors for red deer.

  19. Invaders do not require high resource levels to maintain physiological advantages in a temperate deciduous forest.

    Science.gov (United States)

    Heberling, J Mason; Fridley, Jason D

    2016-04-01

    Non-native, invasive plants are commonly typified by trait strategies associated with high resource demands and plant invasions are often thought to be dependent upon site resource availability or disturbance. However, the invasion of shade-tolerant woody species into deciduous forests of the Eastern United States seems to contradict such generalization, as growth in this ecosystem is strongly constrained by light and, secondarily, nutrient stress. In a factorial manipulation of light and soil nitrogen availability, we established an experimental resource gradient in a secondary deciduous forest to test whether three common, woody, invasive species displayed increased metabolic performance and biomass production compared to six co-occurring woody native species, and whether these predicted differences depend upon resource supply. Using hierarchical Bayesian models of photosynthesis that included leaf trait effects, we found that invasive species exhibited functional strategies associated with higher rates of carbon gain. Further, invader metabolic and growth-related attributes were more responsive to increasing light availability than those of natives, but did not fall below average native responses even in low light. Surprisingly, neither group showed direct trait or growth responses to soil N additions. However, invasive species showed increased photosynthetic nitrogen use efficiencies with decreasing N availability, while that of natives remained constant. Although invader advantage over natives was amplified in higher resource conditions in this forest, our results indicate that some invasive species can maintain physiological advantages over co-occurring natives regardless of resource conditions.

  20. The presence of Abronia oaxacae (Squamata: Anguidae in tank bromeliads in temperate forests of Oaxaca, Mexico

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    GI. Cruz-Ruiz

    Full Text Available The presence of lizards in bromeliads has been widely documented. Nevertheless, the possibility of some type of preference or specificity among lizards for particular bromeliad species has not yet been investigated. Therefore, this study aims to document the presence of Abronia oaxacae in six species of tank bromeliads found in pine forests, pine-live oak forests, and live oak groves during both the rainy season and the dry season. Three adult individuals of Abronia oaxacae were collected; one in a Tillandsia violácea (pine-live oak forest, one in a T. calothyrsus (live oak grove, and one in a T. prodigiosa (live oak grove. All three specimens were collected in sampling efforts carried out during the dry season. The results of the present study suggest that A. oaxacae shows no preference for a single, specific bromeliad species, although it does have a certain preference for a few select species. The presence of A. oaxacae in bromeliads during the dry season could be related to the cooler, moister microhabitat that these plants represent.

  1. Factors affecting spatial variation of annual apparent Q₁₀ of soil respiration in two warm temperate forests.

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    Junwei Luan

    Full Text Available A range of factors has been identified that affect the temperature sensitivity (Q₁₀ values of the soil-to-atmosphere CO₂ flux. However, the factors influencing the spatial distribution of Q₁₀ values within warm temperate forests are poorly understood. In this study, we examined the spatial variation of Q₁₀ values and its controlling factors in both a naturally regenerated oak forest (OF and a pine plantation (PP. Q₁₀ values were determined based on monthly soil respiration (R(S measurements at 35 subplots for each stand from Oct. 2008 to Oct. 2009. Large spatial variation of Q₁₀ values was found in both OF and PP, with their respective ranges from 1.7 to 5.12 and from 2.3 to 6.21. In PP, fine root biomass (FR (R = 0.50, P = 0.002, non-capillary porosity (NCP (R = 0.37, P = 0.03, and the coefficients of variation of soil temperature at 5 cm depth (CV of T₅ (R = -0.43, P = 0.01 well explained the spatial variance of Q₁₀. In OF, carbon pool lability reflected by light fractionation method (LLFOC well explained the spatial variance of Q₁₀ (R = -0.35, P = 0.04. Regardless of forest type, LLFOC and FR correlation with the Q₁₀ values were significant and marginally significant, respectively; suggesting a positive relationship between substrate availability and apparent Q₁₀ values. Parameters related to gas diffusion, such as average soil water content (SWC and NCP, negatively or positively explained the spatial variance of Q₁₀ values. Additionally, we observed significantly higher apparent Q₁₀ values in PP compared to OF, which might be partly attributed to the difference in soil moisture condition and diffusion ability, rather than different substrate availabilities between forests. Our results suggested that both soil chemical and physical characters contributed to the observed large Q₁₀ value variation.

  2. Temporal variability of the NPP-GPP ratio at seasonal and interannual time scales in a temperate beech forest

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    M. Campioli

    2011-09-01

    Full Text Available The allocation of carbon (C taken up by the tree canopy for respiration and production of tree organs with different construction and maintenance costs, life span and decomposition rate, crucially affects the residence time of C in forests and their C cycling rate. The carbon-use efficiency, or ratio between net primary production (NPP and gross primary production (GPP, represents a convenient way to analyse the C allocation at the stand level. In this study, we extend the current knowledge on the NPP-GPP ratio in forests by assessing the temporal variability of the NPP-GPP ratio at interannual (for 8 years and seasonal (for 1 year scales for a young temperate beech stand, reporting dynamics for both leaves and woody organs, in particular stems. NPP was determined with biometric methods/litter traps, whereas the GPP was estimated via the eddy covariance micrometeorological technique.

    The interannual variability of the proportion of C allocated to leaf NPP, wood NPP and leaf plus wood NPP (on average 11% yr−1, 29% yr−1 and 39% yr−1, respectively was significant among years with up to 12% yr−1 variation in NPP-GPP ratio. Studies focusing on the comparison of NPP-GPP ratio among forests and models using fixed allocation schemes should take into account the possibility of such relevant interannual variability. Multiple linear regressions indicated that the NPP-GPP ratio of leaves and wood significantly correlated with environmental conditions. Previous year drought and air temperature explained about half of the NPP-GPP variability of leaves and wood, respectively, whereas the NPP-GPP ratio was not decreased by severe drought, with large NPP-GPP ratio on 2003 due mainly to low GPP. During the period between early May and mid June, the majority of GPP was allocated to leaf and stem NPP, whereas these sinks were of little importance later on. Improved estimation of seasonal GPP and of the

  3. Long-Term Fire Regime Estimated from Soil Charcoal in Coastal Temperate Rainforests

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    Ken Lertzman

    2002-12-01

    Full Text Available Coastal temperate rainforests from southeast Alaska through to southern Oregon are ecologically distinct from forests of neighboring regions, which have a drier, or more continental, climate and disturbance regimes dominated by fires. The long-term role of fire remains one of the key outstanding sources of uncertainty in the historical dynamics of the wetter and less seasonal forests that dominate the northerly two thirds of the rainforest region in British Columbia and Alaska. Here, we describe the long-term fire regime in two forests on the south coast of British Columbia by means of 244 AMS radiocarbon dates of charcoal buried in forest soils. In both forests, some sites have experienced no fire over the last 6000 years and many other sites have experienced only one or two fires during that time. Intervals between fires vary from a few centuries to several thousand years. In contrast to other conifer forests, this supports a model of forest dynamics where fires are of minor ecological importance. Instead, forest history is dominated by fine-scale processes of disturbance and recovery that maintain an ubiquitous late-successional character over the forest landscape. This has significant implications for ecosystem-based forest management and our understanding of carbon storage in forest soils.

  4. Long-Term Impacts of China’s New Commercial Harvest Exclusion Policy on Ecosystem Services and Biodiversity in the Temperate Forests of Northeast China

    Directory of Open Access Journals (Sweden)

    Kai Liu

    2018-04-01

    Full Text Available Temperate forests in Northeast China have been severely exploited by timber harvesting in the last century. To reverse this trend, China implemented the Classified Forest Management policy in the Natural Forest Conservation Program in 1998 to protect forests from excessive harvesting. However, the policy was unable to meet the 2020 commitment of increasing growing stock (set in the Kyoto Protocol because of high-intensity harvesting. Accordingly, China banned all commercial harvesting in Northeast China in 2014. In this study, we investigated the long-term impacts of the no commercial harvest (NCH policy on ecosystem services and biodiversity using a forest landscape model, LANDIS PRO 7.0, in the temperate forests of the Small Khingan Mountains, Northeast China. We designed three management scenarios: The H scenario (the Classified Forest Management policy used in the past, the NCH scenario (the current Commercial Harvest Exclusion policy, and the LT scenario (mitigation management, i.e., light thinning. We compared total aboveground forest biomass, biomass by tree species, abundance of old-growth forests, and diversity of tree species and age class in three scenarios from 2010 to 2100. We found that compared with the H scenario, the NCH scenario increased aboveground forest biomass, abundance of old-growth forests, and biomass of most timber species over time; however, it decreased the biomass of rare and protected tree species and biodiversity. We found that the LT scenario increased the biomass of rare and protected tree species and biodiversity in comparison with the NCH scenario, while it maintained aboveground forest biomass and abundance of old-growth forests at a high level (slightly less than the NCH scenario. We concluded there was trade-off between carbon storage and biodiversity. We also concluded that light thinning treatment was able to regulate the trade-off and alleviate the negative effects associated with the NCH policy. Our

  5. Allometric Equations for Estimating Biomass and Carbon Stocks in the Temperate Forests of North-Western Mexico

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    Benedicto Vargas-Larreta

    2017-07-01

    Full Text Available This paper presents new equations for estimating above-ground biomass (AGB and biomass components of seventeen forest species in the temperate forests of northwestern Mexico. A data set corresponding to 1336 destructively sampled oak and pine trees was used to fit the models. The generalized method of moments was used to simultaneously fit systems of equations for biomass components and AGB, to ensure additivity. In addition, the carbon content of each tree component was calculated by the dry combustion method, in a TOC analyser. The results of cross-validation indicated that the fitted equations accounted for on average 91%, 82%, 83% and 76% of the observed variance in stem wood and stem bark, branch and foliage biomass, respectively, whereas the total AGB equations explained on average 93% of the total observed variance in AGB. The inclusion of total height (h or diameter at breast height2 × total height (d2h as a predictor in the d-only based equations systems slightly improved estimates for stem wood, stem bark and total above-ground biomass, and greatly improved the estimates produced by the branch and foliage biomass equations. The predictive power of the proposed equations is higher than that of existing models for the study area. The fitted equations were used to estimate stand level AGB stocks from data on growing stock in 429 permanent sampling plots. Three machine-learning techniques were used to model the estimated stand level AGB and carbon contents; the selected models were used to map the AGB and carbon distributions in the study area, for which mean values of respectively 129.84 Mg ha−1 and 63.80 Mg ha−1 were obtained.

  6. Leaf litter and roots as sources of mineral soil organic matter in temperate deciduous forest with and without earthworms

    Science.gov (United States)

    Fahey, T.; Yavitt, J. B.

    2012-12-01

    We labeled sugar maple trees with 13C to quantify the separate contributions of decaying leaf litter and root turnover/rhizosphere C flux to mineral soil organic matter (SOM). Labeled leaf litter was applied to forest plots with and without earthworms and recovery of the label in SOM was quantified over three years. In parallel, label recovery was quantified in soils from the labeling chambers where all label was supplied by belowground C flux. In the absence of earthworms about half of the label added as leaf litter remained in the surface organic horizons after three years, with about 3% recovered in mineral SOM. The label was most enriched on silt + clay surfaces, representing precipitation of DOC derived from litter. Earthworms mixed nearly all the leaf litter into mineral soil within one year, and after two years the label was most enriched in particulate organic matter held within soil aggregates produced by worms. After three years 15-20% of the added label was recovered in mineral SOM. In the labeling chambers over 75% of belowground C allocation (BCA) was used in root and rhizosphere respiration in the first year after labeling. We recovered only 3.8% of estimated BCA in SOM after 3 years; however, expressed as a proportion of fine root production plus rhizosphere C flux, this value is 15.4%, comparable to that for leaf litter in the presence of earthworms. In conclusion, both roots and leaf litter contribute significantly to the formation of stabilized mineral SOM in temperate deciduous forests, and this process is profoundly altered by the invasion of lumbricid earthworms.

  7. [Effects of bryophytes in dark coniferous forest of Changbai Mountains on three conifers seed germination and seedling growth].

    Science.gov (United States)

    Lin, Fei; Hao, Zhanqing; Ye, Ji; Jiang, Ping

    2006-08-01

    This paper studied the effects of Hylocomium splendens and Rhytidiadelphus triquetrus, the main bryophytes in dark coniferous forests of Changbai Mountains, on the seed germination and seedling growth of Pinus koraiensis, Picea koraiensis and Larix olgensis. The results indicated that at definite concentrations, the water extract of H. splendens inhibited Picea koraiensis seed germination, while that of R. triquetrus promoted it. Although the water extracts of the two bryophytes had no obvious effects on the seed germination of Picea koraiensis and Larix olgensis, they expedited the occurrence of the tree species' daily germination peak. The water extracts of test bryophytes inhibited the seedling growth of P. koraiensis and Picea koraiensis, but promoted that of Larix olgensis. The living shoots of the two bryophytes had no obvious effects on the seed germination of Picea koraiensis and Larix olgensis, but delayed the daily germination peak of Picea koraiensis while promoted that of Larix olgensis, andthe killed shoots inhibited the seed germination of all test tree species. Living shoots in larger amounts promoted the seedling growth of Picea koraiensis and Larix olgensis, but killed shoots were inadverse.

  8. Contrasting food web linkages for the grazing pathway in 3 temperate forested streams using {sup 15}N as a tracer

    Energy Technology Data Exchange (ETDEWEB)

    Tank, J.L.; Mulholland, P.J.; Meyer, J.L.; Bowden, W.B.; Webster, J.R.; Peterson, B.J.

    1998-11-01

    Nitrogen is a critical element controlling the productivity and dynamics of stream ecosystems and many streams are limited by the supply of biologically available nitrogen. The authors are learning more about the fate of inorganic nitrogen entering streams through {sup 15}N tracer additions. The Lotic Intersite Nitrogen Experiment (LINX) is studying the uptake, cycling, and fate of {sup 15}N-NH{sub 4} in the stream food web of 10 streams draining different biomes. Using the {sup 15}N tracer method and data from 3 sites in the study, the authors can differentiate patterns in the cycling of nitrogen through the grazing pathway (N from the epilithon to grazing macroinvertebrates) for 3 temperate forested streams. Here, they quantify the relationship between the dominant grazer and its proposed food resource, the epilithon, by comparing {sup 15}N levels of grazers with those of the epilithon, as well as the biomass, nitrogen content, and chlorophyll a standing stocks of the epilithon in 3 streams.

  9. Detection of phytohormones in temperate forest fungi predicts consistent abscisic acid production and a common pathway for cytokinin biosynthesis.

    Science.gov (United States)

    Morrison, Erin N; Knowles, Sarah; Hayward, Allison; Thorn, R Greg; Saville, Barry J; Emery, R J N

    2015-01-01

    The phytohormones, abscisic acid and cytokinin, once were thought to be present uniquely in plants, but increasing evidence suggests that these hormones are present in a wide variety of organisms. Few studies have examined fungi for the presence of these "plant" hormones or addressed whether their levels differ based on the nutrition mode of the fungus. This study examined 20 temperate forest fungi of differing nutritional modes (ectomycorrhizal, wood-rotting, saprotrophic). Abscisic acid and cytokinin were present in all fungi sampled; this indicated that the sampled fungi have the capacity to synthesize these two classes of phytohormones. Of the 27 cytokinins analyzed by HPLC-ESI MS/MS, seven were present in all fungi sampled. This suggested the existence of a common cytokinin metabolic pathway in fungi that does not vary among different nutritional modes. Predictions regarding the source of isopentenyl, cis-zeatin and methylthiol CK production stemming from the tRNA degradation pathway among fungi are discussed. © 2015 by The Mycological Society of America.

  10. Non-native grass invasion associated with increases in insect diversity in temperate forest understory

    Science.gov (United States)

    Metcalf, Judith L.; Emery, Sarah M.

    2015-11-01

    Invasive plants can alter the structure and function of plant communities to such a degree that they can also have significant impacts on the insect communities. Because insects play an important role in many ecosystems, changes in these communities could have important implications, beyond their biodiversity value, for ecosystem function and diversity at other trophic levels. Microstegium vimineum is an annual C4 grass that is invasive in many eastern North American deciduous forests. Because this grass plays an important role in determining the plant community structure in the understory of these forests, it also has the potential to significantly alter understory insect communities. In this study we evaluated the relationship between M. vimineum and understory insect communities in a forest reserve in Kentucky, USA. Total insect abundance, richness and diversity showed a positive association with M. vimineum presence. Trophic analysis showed significantly higher abundances of herbivores where M. vimineum was present. Forb abundance, which serves as the primary food source for herbivorous insects in this system, was lower in sites invaded with M. vimineum. Invasion by this non-native was also associated with significant increases in aboveground plant biomass which was nearly 50% greater in invaded sites. These results indicate that the understory insect community may be responding to increased biomass rather than the loss of native forb food resources, which contradicts other studies that have examined relationships between M. vimineum invasion and insects. Our results provide evidence that invasive plants can provide benefits for other trophic levels, even when native plant biodiversity is lost.

  11. Contrasting patterns of fine-scale herb layer species composition in temperate forests

    Science.gov (United States)

    Chudomelová, Markéta; Zelený, David; Li, Ching-Feng

    2017-04-01

    Although being well described at the landscape level, patterns in species composition of forest herb layer are rarely studied at smaller scales. Here, we examined fine-scale environmental determinants and spatial structures of herb layer communities in thermophilous oak- and hornbeam dominated forests of the south-eastern part of the Czech Republic. Species composition of herb layer vegetation and environmental variables were recorded within a fixed grid of 2 × 2 m subplots regularly distributed within 1-ha quadrate plots in three forest stands. For each site, environmental models best explaining species composition were constructed using constrained ordination analysis. Spatial eigenvector mapping was used to model and account for spatial structures in community variation. Mean Ellenberg indicator values calculated for each subplot were used for ecological interpretation of spatially structured residual variation. The amount of variation explained by environmental and spatial models as well as the selection of variables with the best explanatory power differed among sites. As an important environmental factor, relative elevation was common to all three sites, while pH and canopy openness were shared by two sites. Both environmental and community variation was mostly coarse-scaled, as was the spatially structured portion of residual variation. When corrected for bias due to spatial autocorrelation, those environmental factors with already weak explanatory power lost their significance. Only a weak evidence of possibly omitted environmental predictor was found for autocorrelated residuals of site models using mean Ellenberg indicator values. Community structure was determined by different factors at different sites. The relative importance of environmental filtering vs. spatial processes was also site specific, implying that results of fine-scale studies tend to be shaped by local conditions. Contrary to expectations based on other studies, overall dominance of

  12. Palynology and the Ecology of the New Zealand Conifers

    Directory of Open Access Journals (Sweden)

    Matt S. McGlone

    2017-11-01

    Full Text Available The New Zealand conifers (20 species of trees and shrubs in the Araucariaceae, Podocarpaceae, and Cupressaceae are often regarded as ancient Gondwanan elements, but mostly originated much later. Often thought of as tall trees of humid, warm forests, they are present throughout in alpine shrublands, tree lines, bogs, swamps, and in dry, frost-prone regions. The tall conifers rarely form purely coniferous forest and mostly occur as an emergent stratum above evergreen angiosperm trees. During Maori settlement in the thirteenth century, fire-sensitive trees succumbed rapidly, most of the drier forests being lost. As these were also the more conifer-rich forests, ecological research has been skewed toward conifer dynamics of forests wetter and cooler than the pre-human norm. Conifers are well represented in the pollen record and we here we review their late Quaternary history in the light of what is known about their current ecology with the intention of countering this bias. During glacial episodes, all trees were scarce south of c. 40° S, and extensive conifer-dominant forest was confined to the northern third of the North Island. Drought- and cold-resistant Halocarpus bidwillii and Phyllocladus alpinus formed widespread scrub in the south. During the deglacial, beginning 18,000 years ago, tall conifers underwent explosive spread to dominate the forest biomass throughout. Conifer dominance lessened in favor of angiosperms in the wetter western lowland forests over the Holocene but the dryland eastern forests persisted largely unchanged until settlement. Mid to late Holocene climate change favored the more rapidly growing Nothofagaceae which replaced the previous conifer-angiosperm low forest or shrubland in tree line ecotones and montane areas. The key to this dynamic conifer history appears to be their bimodal ability to withstand stress, and dominate on poor soils and in cool, dry regions but, in wetter, warmer locations, to slowly grow thorough

  13. Floodplain forest succession reveals fluvial processes: A hydrogeomorphic model for temperate riparian woodlands.

    Science.gov (United States)

    Egger, Gregory; Politti, Emilio; Lautsch, Erwin; Benjankar, Rohan; Gill, Karen M; Rood, Stewart B

    2015-09-15

    River valley floodplains are physically-dynamic environments where fluvial processes determine habitat gradients for riparian vegetation. These zones support trees and shrubs whose life stages are adapted to specific habitat types and consequently forest composition and successional stage reflect the underlying hydrogeomorphic processes and history. In this study we investigated woodland vegetation composition, successional stage and habitat properties, and compared these with physically-based indicators of hydraulic processes. We thus sought to develop a hydrogeomorphic model to evaluate riparian woodland condition based on the spatial mosaic of successional phases of the floodplain forest. The study investigated free-flowing and dam-impacted reaches of the Kootenai and Flathead Rivers, in Idaho and Montana, USA and British Columbia, Canada. The analyses revealed strong correspondence between vegetation assessments and metrics of fluvial processes indicating morphodynamics (erosion and shear stress), inundation and depth to groundwater. The results indicated that common successional stages generally occupied similar hydraulic environments along the different river segments. Comparison of the spatial patterns between the free-flowing and regulated reaches revealed greater deviation from the natural condition for the braided channel segment than for the meandering segment. This demonstrates the utility of the hydrogeomorphic approach and suggests that riparian woodlands along braided channels could have lower resilience than those along meandering channels and might be more vulnerable to influences such as from river damming or climate change. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Landscape fuel reduction, forest fire, and biophysical linkages to local habitat use and local persistence of fishers (Pekania pennanti) in Sierra Nevada mixed-conifer forests

    Science.gov (United States)

    R.A. Sweitzer; B.J. Furnas; R.H. Barrett; Kathryn Purcell; Craig Thompson

    2016-01-01

    Fire suppression and logging have contributed to major changes in California’s Sierra Nevada forests. Strategically placed landscape treatments (SPLATS) are being used to reduce density of trees, shrubs, and surface fuels to limit wildfire intensity and spread, but may negatively impact fishers (Pekania pennanti). We used camera traps to survey for...

  15. Manganese in the litter fall-forest floor continuum of boreal and temperate pine and spruce forest ecosystems

    DEFF Research Database (Denmark)

    Berg, Björn; Erhagen, Björn; Johansson, Maj-Britt

    2015-01-01

    pine needle litter significantly faster (p litter of Norway spruce. Over Northern Europe concentrations of total Mn in mor humus as well as extractable Mn in the mineral soil increase with decreasing MAT and over a climatic gradient the Mn concentrations in Norway......We have reviewed the literature on the role of manganese (Mn) in the litter fall-to-humus subsystem. Available data gives a focus on North European coniferous forests. Manganese concentrations in pine (Pinus spp.) foliar litter are highly variable both spatially and temporally within the same...... litter species and for the genus Pinus we found a range from 0.03 to 3.7 mg g−1. Concentrations were related negatively to site mean annual temperature (MAT) and annual actual evapotranspiration (AET) for pine species litter but not for that of Norway spruce (Picea abies) as a single species. Combined...

  16. Phylobetadiversity among forest types in the Brazilian Atlantic Forest complex.

    Science.gov (United States)

    Duarte, Leandro Da Silva; Bergamin, Rodrigo Scarton; Marcilio-Silva, Vinícius; Seger, Guilherme Dubal Dos Santos; Marques, Márcia Cristina Mendes

    2014-01-01

    Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests). We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index) and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao's H). Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand, tropical groups, like

  17. Phylobetadiversity among forest types in the Brazilian Atlantic Forest complex.

    Directory of Open Access Journals (Sweden)

    Leandro Da Silva Duarte

    Full Text Available Phylobetadiversity is defined as the phylogenetic resemblance between communities or biomes. Analyzing phylobetadiversity patterns among different vegetation physiognomies within a single biome is crucial to understand the historical affinities between them. Based on the widely accepted idea that different forest physiognomies within the Southern Brazilian Atlantic Forest constitute different facies of a single biome, we hypothesize that more recent phylogenetic nodes should drive phylobetadiversity gradients between the different forest types within the Atlantic Forest, as the phylogenetic divergence among those forest types is biogeographically recent. We compiled information from 206 checklists describing the occurrence of shrub/tree species across three different forest physiognomies within the Southern Brazilian Atlantic Forest (Dense, Mixed and Seasonal forests. We analyzed intra-site phylogenetic structure (phylogenetic diversity, net relatedness index and nearest taxon index and phylobetadiversity between plots located at different forest types, using five different methods differing in sensitivity to either basal or terminal nodes (phylogenetic fuzzy weighting, COMDIST, COMDISTNT, UniFrac and Rao's H. Mixed forests showed higher phylogenetic diversity and overdispersion than the other forest types. Furthermore, all forest types differed from each other in relation phylobetadiversity patterns, particularly when phylobetadiversity methods more sensitive to terminal nodes were employed. Mixed forests tended to show higher phylogenetic differentiation to Dense and Seasonal forests than these latter from each other. The higher phylogenetic diversity and phylobetadiversity levels found in Mixed forests when compared to the others likely result from the biogeographical origin of several taxa occurring in these forests. On one hand, Mixed forests shelter several temperate taxa, like the conifers Araucaria and Podocarpus. On the other hand

  18. Temperature sensitivity of microbial respiration of fine root litter in a temperate broad-leaved forest.

    Science.gov (United States)

    Makita, Naoki; Kawamura, Ayumi

    2015-01-01

    The microbial decomposition respiration of plant litter generates a major CO2 efflux from terrestrial ecosystems that plays a critical role in the regulation of carbon cycling on regional and global scales. However, the respiration from root litter decomposition and its sensitivity to temperature changes are unclear in current models of carbon turnover in forest soils. Thus, we examined seasonal changes in the temperature sensitivity and decomposition rates of fine root litter of two diameter classes (0-0.5 and 0.5-2.0 mm) of Quercus serrata and Ilex pedunculosa in a deciduous broad-leaved forest. During the study period, fine root litter of both diameter classes and species decreased approximately exponentially over time. The Q10 values of microbial respiration rates of root litter for the two classes were 1.59-3.31 and 1.28-6.27 for Q. serrata and 1.36-6.31 and 1.65-5.86 for I. pedunculosa. A significant difference in Q10 was observed between the diameter classes, indicating that root diameter represents the initial substrate quality, which may determine the magnitude of Q10 value of microbial respiration. Changes in these Q10 values were related to seasonal soil temperature patterns; the values were higher in winter than in summer. Moreover, seasonal variations in Q10 were larger during the 2-year decomposition period than the 1-year period. These results showed that the Q10 values of fine root litter of 0-0.5 and 0.5-2.0 mm have been shown to increase with lower temperatures and with the higher recalcitrance pool of the decomposed substrate during 2 years of decomposition. Thus, the temperature sensitivity of microbial respiration in root litter showed distinct patterns according to the decay period and season because of the temperature acclimation and adaptation of the microbial decomposer communities in root litter.

  19. Mean age of carbon in fine roots from temperate forests and grasslands with different management

    Directory of Open Access Journals (Sweden)

    E. Solly

    2013-07-01

    Full Text Available Fine roots are the most dynamic portion of a plant's root system and a major source of soil organic matter. By altering plant species diversity and composition, soil conditions and nutrient availability, and consequently belowground allocation and dynamics of root carbon (C inputs, land-use and management changes may influence organic C storage in terrestrial ecosystems. In three German regions, we measured fine root radiocarbon (14C content to estimate the mean time since C in root tissues was fixed from the atmosphere in 54 grassland and forest plots with different management and soil conditions. Although root biomass was on average greater in grasslands 5.1 ± 0.8 g (mean ± SE, n = 27 than in forests 3.1 ± 0.5 g (n = 27 (p p r = 0.65 and with the number of perennial species (r = 0.77. Fine root mean C age in grasslands was also affected by study region with averages of 0.7 ± 0.1 yr (n = 9 on mostly organic soils in northern Germany and of 1.8 ± 0.3 yr (n = 9 and 2.6 ± 0.3 (n = 9 in central and southern Germany (p < 0.05. This was probably due to differences in soil nutrient contents and soil moisture conditions between study regions, which affected plant species diversity and the presence of perennial species. Our results indicate more long-lived roots or internal redistribution of C in perennial species and suggest linkages between fine root C age and management in grasslands. These findings improve our ability to predict and model belowground C fluxes across broader spatial scales.

  20. Analysing taxonomic structures and local ecological processes in temperate forests in North Eastern China.

    Science.gov (United States)

    Fan, Chunyu; Tan, Lingzhao; Zhang, Chunyu; Zhao, Xiuhai; von Gadow, Klaus

    2017-10-30

    One of the core issues of forest community ecology is the exploration of how ecological processes affect community structure. The relative importance of different processes is still under debate. This study addresses four questions: (1) how is the taxonomic structure of a forest community affected by spatial scale? (2) does the taxonomic structure reveal effects of local processes such as environmental filtering, dispersal limitation or interspecific competition at a local scale? (3) does the effect of local processes on the taxonomic structure vary with the spatial scale? (4) does the analysis based on taxonomic structures provide similar insights when compared with the use of phylogenetic information? Based on the data collected in two large forest observational field studies, the taxonomic structures of the plant communities were analyzed at different sampling scales using taxonomic ratios (number of genera/number of species, number of families/number of species), and the relationship between the number of higher taxa and the number of species. Two random null models were used and the "standardized effect size" (SES) of taxonomic ratios was calculated, to assess possible differences between the observed and simulated taxonomic structures, which may be caused by specific ecological processes. We further applied a phylogeny-based method to compare results with those of the taxonomic approach. As expected, the taxonomic ratios decline with increasing grain size. The quantitative relationship between genera/families and species, described by a linearized power function, showed a good fit. With the exception of the family-species relationship in the Jiaohe study area, the exponents of the genus/family-species relationships did not show any scale dependent effects. The taxonomic ratios of the observed communities had significantly lower values than those of the simulated random community under the test of two null models at almost all scales. Null Model 2 which

  1. Tree species' responses to throughfall removal experiments superimposed on a natural drought event in two contrasting humid temperate forests in New Hampshire, USA

    Science.gov (United States)

    Jennings, Katie; McIntire, Cameron; Coble, Adam; Vandeboncoeur, Matthew; Rustad, Lindsay; Templer, Pamela; Absbjornsen, Heidi

    2017-04-01

    Climate change is likely to affect Northeastern U.S. forests through the increased frequency and severity of drought events. However, our understanding of how these humid temperate forests will respond to moderate to extreme droughts is limited. Given the important role that these forests play in providing ecosystem services and in supplying forest products, enhancing our knowledge about the impacts of drought is critical to guiding forest management and climate change adaptation efforts. We conducted 50% throughfall removal experiments at two contrasting sites in the Northeastern US (Hubbard Brook Experimental Forest and Thompson Farm, NH, USA), which were superimposed on the severe natural drought occurring in August-September 2016. Preliminary analysis suggests that the two sites respond differently to simulated drought. Pinus strobus trees at Thompson Farm reduced their transpiration rates in response to both the natural and experimental drought, particularly evident during a 5-day period at the height of the drought were transpiration nearly ceased. Both P. strobus and Quercus rubra trees increased their water use efficiency in response to reduced soil water availability, with Q. rubra allowing its midday water potential to reach more negative values, consistent with its more drought tolerant strategy compared to P. strobus. In contrast, we did not detect any significant differences in tree transpiration rates or growth in the dominant tree species, Acer rubrum, in response to the experimental drought treatment at Hubbard Brook. However, both soil respiration and fine root biomass production were lower in the drought treatment plots relative to the control plots at Hubbard Brook. We plan to continue these throughfall removal experiments for at least two more years to better understand the implications of future drought in these humid temperate forests and identify differences in species' physiological adaptations and threshold responses.

  2. Evidence of a reduction in cloud condensation nuclei activity of water-soluble aerosols caused by biogenic emissions in a cool-temperate forest.

    Science.gov (United States)

    Müller, Astrid; Miyazaki, Yuzo; Tachibana, Eri; Kawamura, Kimitaka; Hiura, Tsutom

    2017-08-16

    Biogenic organic aerosols can affect cloud condensation nuclei (CCN) properties, and subsequently impact climate change. Large uncertainties exist in how the difference in the types of terrestrial biogenic sources and the abundance of organics relative to sulfate affect CCN properties. For the submicron water-soluble aerosols collected for two years in a cool-temperate forest in northern Japan, we show that the hygroscopicity parameter κ CCN (0.44 ± 0.07) exhibited a distinct seasonal trend with a minimum in autumn (κ CCN  = 0.32-0.37); these κ CCN values were generally larger than that of ambient particles, including water-insoluble fractions. The temporal variability of κ CCN was controlled by the water-soluble organic matter (WSOM)-to-sulfate ratio (R 2  > 0.60), where the significant reduction of κ CCN in autumn was linked to the increased WSOM/sulfate ratio. Positive matrix factorization analysis indicates that α-pinene-derived secondary organic aerosol (SOA) substantially contributed to the WSOM mass (~75%) in autumn, the majority of which was attributable to emissions from litter/soil microbial activity near the forest floor. These findings suggest that WSOM, most likely α-pinene SOA, originated from the forest floor can significantly suppress the aerosol CCN activity in cool-temperate forests, which have implications for predicting climate effects by changes in biogenic emissions in future.

  3. VOC emissions from a temperate mixed forest in Belgium measured by eddy-covariance

    Science.gov (United States)

    Laffineur, Q.; Heinesch, B.; Aubinet, M.; Amelynck, C.; Schoon, N.; Müller, J.-F.; Joó, E.; Dewulf, J.; van Langenhove, H.

    2010-05-01

    Forest ecosystems are known to be important emitters of Biogenic Volatile Organic Compounds (BVOC). They play an important role in the atmospheric chemistry and may contribute to the formation of ozone and aerosols with consequences on air quality and on climate. In order to better understand the effects of environmental parameters on the emissions, micrometeorological flux measurements were carried out above a mixed forest (Fagus sylvatica, Pseudotsuga menziesii, Abies alba, Picea abies) at the Vielsalm experimental site (Belgium) from July to November 2009. The flux measurements were obtained by the eddy-covariance technique using proton transfer reaction mass spectrometry. In our first measurement campaign, among other VOC compounds, isoprene (m/z 69) and monoterpenoid compounds (m/z 137) have been measured continuously with a data coverage of 75 and 58 % respectively, allowing robust statistical analysis. In our analysis, we focused on these two main emissions. A footprint analysis showed that Fagus sylvatica seems to be the main emitter of m/z 137 and Abies alba seems to be the main emitter of m/z 69. BVOCs fluxes present an exponential response to temperature. This response is more pronounced for m/z 69 while it shows the strongest seasonal evolution for m/z 137. A light dependence of m/z 69 and m/z 137 fluxes was observed but the relationship did not exhibit the same behaviour before (hyperbolic relation) and after midday (linear relation). This behaviour difference induced a hysteresis effect on the daily evolution of averaged fluxes. A robust local minimum was also observed just before midday for m/z 69 (less obvious for m/z 137) during July-August period. This minimum is not observed in the CO2 fluxes which are also measured in Vielsalm. The light dependence of BVOC emissions suggests that m/z 69 and m/z 137 emissions are directly linked to the photosynthetic cycle but the presence of the midday local minimum suggests that other processes influence the

  4. Disturbance regimes, gap-demanding trees and seed mass related to tree height in warm temperate rain forests worldwide.

    Science.gov (United States)

    Grubb, Peter J; Bellingham, Peter J; Kohyama, Takashi S; Piper, Frida I; Valido, Alfredo

    2013-08-01

    For tropical lowland rain forests, Denslow (1987) hypothesized that in areas with large-scale disturbances tree species with a high demand for light make up a larger proportion of the flora; results of tests have been inconsistent. There has been no test for warm temperate rain forests (WTRFs), but they offer a promising testing ground because they differ widely in the extent of disturbance. WTRF is dominated by microphylls sensu Raunkiaer and has a simpler structure and range of physiognomy than tropical or subtropical rain forests. It occurs in six parts of the world: eastern Asia, New Zealand, Chile, South Africa, SE Australia and the Azores. On the Azores it has been mostly destroyed, so we studied instead the subtropical montane rain forest (STMRF) on the Canary Islands which also represents a relict of the kind of WTRF that once stretched across southern Eurasia. We sought to find whether in these six regions the proportion of tree species needing canopy gaps for establishment reflects the frequency and/or extent of canopy disturbance by wind, landslide, volcanic eruptions (lava flow and ash fall), flood or fire. We used standard floras and ecological accounts to draw up lists of core tree species commonly reaching 5 m height. We excluded species which are very rare, very localized in distribution, or confined to special habitats, e.g. coastal forests or rocky sites. We used published accounts and our own experience to classify species into three groups: (1) needing canopy gaps for establishment; (2) needing either light shade throughout or a canopy gap relatively soon (a few months or years) after establishment; and (3) variously more shade-tolerant. Group 1 species were divided according the kind of canopy opening needed: tree-fall gap, landslide, lava flow, flood or fire. Only some of the significant differences in proportion of Group 1 species were consistent with differences in the extent of disturbance; even in some of those cases other factors seem

  5. Effects of thinning on drought vulnerability and climate response in north temperate forest ecosystems.

    Science.gov (United States)

    D'Amato, Anthony W; Bradford, John B; Fraver, Shawn; Palik, Brian J

    2013-12-01

    Reducing tree densities through silvicultural thinning has been widely advocated as a strategy for enhancing resistance and resilience to drought, yet few empirical evaluations of this approach exist. We examined detailed dendrochronological data from a long-term (> 50 years) replicated thinning experiment to determine if density reductions conferred greater resistance and/or resilience to droughts, assessed by the magnitude of stand-level growth reductions. Our results suggest that thinning generally enhanced drought resistance and resilience; however, this relationship showed a pronounced reversal over time in stands maintained at lower tree densities. Specifically, lower-density stands exhibited greater resistance and resilience at younger ages (49 years), yet exhibited lower resistance and resilience at older ages (76 years), relative to higher-density stands. We attribute this reversal to significantly greater tree sizes attained within the lower-density stands through stand development, which in turn increased tree-level water demand during the later droughts. Results from response-function analyses indicate that thinning altered growth-climate relationships, such that higher-density stands were more sensitive to growing-season precipitation relative to lower-density stands. These results confirm the potential of density management to moderate drought impacts on growth, and they highlight the importance of accounting for stand structure when predicting climate-change impacts to forests.

  6. Wetland influence on mercury fate and transport in a temperate forested watershed

    International Nuclear Information System (INIS)

    Selvendiran, Pranesh; Driscoll, Charles T.; Bushey, Joseph T.; Montesdeoca, Mario R.

    2008-01-01

    The transport and fate of mercury (Hg) was studied in two forest wetlands; a riparian peatland and an abandoned beaver meadow. The proportion of total mercury (THg) that was methyl mercury (% MeHg) increased from 2% to 6% from the upland inlets to the outlet of the wetlands. During the growing season, MeHg concentrations were approximately three times higher (0.27 ng/L) than values during the non-growing season (0.10 ng/L). Transport of Hg species was facilitated by DOC production as indicated by significant positive relations with THg and MeHg. Elevated concentrations of MeHg and % MeHg (as high as 70%) were found in pore waters of the riparian and beaver meadow wetlands. Groundwater interaction with the stream was limited at the riparian peatland due to the low hydraulic conductivity of the peat. The annual fluxes of THg and MeHg at the outlet of the watershed were 2.3 and 0.092 μg/m 2 -year respectively. - Wetlands are sources of THg and MeHg; the production of MeHg is seasonally dependent and driven by sulfate reduction in wetlands

  7. Towards Automated Characterization of Canopy Layering in Mixed Temperate Forests Using Airborne Laser Scanning

    Directory of Open Access Journals (Sweden)

    Reik Leiterer

    2015-11-01

    Full Text Available Canopy layers form essential structural components, affecting stand productivity and wildlife habitats. Airborne laser scanning (ALS provides horizontal and vertical information on canopy structure simultaneously. Existing approaches to assess canopy layering often require prior information about stand characteristics or rely on pre-defined height thresholds. We developed a multi-scale method using ALS data with point densities >10 pts/m2 to determine the number and vertical extent of canopy layers (canopylayer, canopylength, seasonal variations in the topmost canopy layer (canopytype, as well as small-scale heterogeneities in the canopy (canopyheterogeneity. We first tested and developed the method on a small forest patch (800 ha and afterwards tested transferability and robustness of the method on a larger patch (180,000 ha. We validated the approach using an extensive set of ground data, achieving overall accuracies >77% for canopytype and canopyheterogeneity, and >62% for canopylayer and canopylength. We conclude that our method provides a robust characterization of canopy layering supporting automated canopy structure monitoring.

  8. New emission factors for Australian vegetation fires measured using open-path Fourier transform infrared spectroscopy - Part 1: Methods and Australian temperate forest fires

    Science.gov (United States)

    Paton-Walsh, C.; Smith, T. E. L.; Young, E. L.; Griffith, D. W. T.; Guérette, É.-A.

    2014-10-01

    Biomass burning releases trace gases and aerosol particles that significantly affect the composition and chemistry of the atmosphere. Australia contributes approximately 8% of gross global carbon emissions from biomass burning, yet there are few previous measurements of emissions from Australian forest fires available in the literature. This paper describes the results of field measurements of trace gases emitted during hazard reduction burns in Australian temperate forests using open-path Fourier transform infrared spectroscopy. In a companion paper, similar techniques are used to characterise the emissions from hazard reduction burns in the savanna regions of the Northern Territory. Details of the experimental methods are explained, including both the measurement set-up and the analysis techniques employed. The advantages and disadvantages of different ways to estimate whole-fire emission factors are discussed and a measurement uncertainty budget is developed. Emission factors for Australian temperate forest fires are measured locally for the first time for many trace gases. Where ecosystem-relevant data are required, we recommend the following emission factors for Australian temperate forest fires (in grams of gas emitted per kilogram of dry fuel burned) which are our mean measured values: 1620 ± 160 g kg-1 of carbon dioxide; 120 ± 20 g kg-1 of carbon monoxide; 3.6 ± 1.1 g kg-1 of methane; 1.3 ± 0.3 g kg-1 of ethylene; 1.7 ± 0.4 g kg-1 of formaldehyde; 2.4 ± 1.2 g kg-1 of methanol; 3.8 ± 1.3 g kg-1 of acetic acid; 0.4 ± 0.2 g kg-1 of formic acid; 1.6 ± 0.6 g kg-1 of ammonia; 0.15 ± 0.09 g kg-1 of nitrous oxide and 0.5 ± 0.2 g kg-1 of ethane.

  9. Modeling Soil Organic Carbon Turnover in Four Temperate Forests Based on Radiocarbon Measurements of Heterotrophic Respiration and Soil Organic Carbon

    Science.gov (United States)

    Ahrens, B.; Borken, W.; Muhr, J.; Schrumpf, M.; Savage, K. E.; Wutzler, T.; Trumbore, S.; Reichstein, M.

    2011-12-01

    Soils of temperate forests store significant amounts of soil organic matter and are considered to be net sinks of atmospheric CO2. Soil organic carbon (SOC) dynamics have been studied using the Δ14C signature of bulk SOC or different SOC fractions as observational constraints in SOC models. Further, the Δ14C signature of CO2 evolved during the incubation of soil and roots has been widely used together with Δ14C of total soil respiration to partition soil respiration into heterotrophic respiration (Rh) and root respiration. However, these data have rarely been used together as observational constraints to determine SOC turnover times. Here, we present a multiple constraints approach, where we used SOC stock and its Δ14C signature, and heterotrophic respiration and its Δ14C signature to estimate SOC turnover times of a simple serial two-pool model via Bayesian optimization. We used data from four temperate forest ecosystems in Germany and the USA with different disturbance and management histories from selective logging to afforestation in the late 19th and early 20th century. The Δ14C signature of the atmosphere with its prominent bomb peak was used as a proxy for the Δ14C signature of aboveground and belowground litterfall. The Δ14C signature of litterfall was lagged behind the atmospheric signal to account for the period between photosynthetic fixation of carbon and its addition to SOC pools. We showed that the combined use of Δ14C measurements of Rh and SOC stocks helped to better constrain turnover times of the fast pool (primarily by Δ14C of Rh) and the slow pool (primarily by Δ14C of SOC). In particular, by introducing two additional parameters that describe the deviation from steady state of the fast and slow cycling pool for both SOC and SO14C, we were able to demonstrate that we cannot maintain the often used steady-state assumption of SOC models in general. Furthermore, a new transport version of our model, including SOC transport via

  10. Can tree species diversity be assessed with Landsat data in a temperate forest?

    Science.gov (United States)

    Arekhi, Maliheh; Yılmaz, Osman Yalçın; Yılmaz, Hatice; Akyüz, Yaşar Feyza

    2017-10-28

    The diversity of forest trees as an indicator of ecosystem health can be assessed using the spectral characteristics of plant communities through remote sensing data. The objectives of this study were to investigate alpha and beta tree diversity using Landsat data for six dates in the Gönen dam watershed of Turkey. We used richness and the Shannon and Simpson diversity indices to calculate tree alpha diversity. We also represented the relationship between beta diversity and remotely sensed data using species composition similarity and spectral distance similarity of sampling plots via quantile regression. A total of 99 sampling units, each 20 m × 20 m, were selected using geographically stratified random sampling method. Within each plot, the tree species were identified, and all of the trees with a diameter at breast height (dbh) larger than 7 cm were measured. Presence/absence and abundance data (tree species number and tree species basal area) of tree species were used to determine the relationship between richness and the Shannon and Simpson diversity indices, which were computed with ground field data, and spectral variables derived (2 × 2 pixels and 3 × 3 pixels) from Landsat 8 OLI data. The Shannon-Weiner index had the highest correlation. For all six dates, NDVI (normalized difference vegetation index) was the spectral variable most strongly correlated with the Shannon index and the tree diversity variables. The Ratio of green to red (VI) was the spectral variable least correlated with the tree diversity variables and the Shannon basal area. In both beta diversity curves, the slope of the OLS regression was low, while in the upper quantile, it was approximately twice the lower quantiles. The Jaccard index is closed to one with little difference in both two beta diversity approaches. This result is due to increasing the similarity between the sampling plots when they are located close to each other. The intercept differences between two

  11. Endocarp thickness affects seed removal speed by small rodents in a warm-temperate broad-leafed deciduous forest, China

    Science.gov (United States)

    Zhang, Hongmao; Zhang, Zhibin

    2008-11-01

    Seed traits are important factors affecting seed predation by rodents and thereby the success of recruitment. Seeds of many tree species have hard hulls. These are thought to confer mechanical protection, but the effect of endocarp thickness on seed predation by rodents has not been well investigated. Wild apricot ( Prunus armeniaca), wild peach ( Amygdalus davidiana), cultivated walnut ( Juglans regia), wild walnut ( Juglans mandshurica Maxim) and Liaodong oak ( Quercus liaotungensis) are very common tree species in northwestern Beijing city, China. Their seeds vary greatly in size, endocarp thickness, caloric value and tannin content. This paper aims to study the effects of seed traits on seed removal speed of these five tree species by small rodents in a temperate deciduous forest, with emphasis on the effect of endocarp thickness. The results indicated that speed of removal of seeds released at stations in the field decreased significantly with increasing endocarp thickness. We found no significant correlations between seed removal speed and other seed traits such as seed size, caloric value and tannin content. In seed selection experiments in small cages, Père David's rock squirrel ( Sciurotamias davidianus), a large-bodied, strong-jawed rodent, selected all of the five seed species, and the selection order among the five seed species was determined by endocarp thickness and the ratio of endocarp mass/seed mass. In contrast, the Korean field mouse ( Apodemus peninsulae) and Chinese white-bellied rat ( Niviventer confucianus), with relatively small bodies and weak jaws, preferred to select small seeds like acorns of Q. liaotungensis and seeds of P. armeniaca, indicating that rodent body size is also an important factor affecting food selection based on seed size. These results suggest endocarp thickness significantly reduces seed removal speed by rodents and then negatively affects dispersal fitness of seeds before seed removal of tree species in the study

  12. The importance of biotic factors in predicting global change effects on decomposition of temperate forest leaf litter.

    Science.gov (United States)

    Rouifed, Soraya; Handa, I Tanya; David, Jean-François; Hättenschwiler, Stephan

    2010-05-01

    Increasing atmospheric CO(2) and temperature are predicted to alter litter decomposition via changes in litter chemistry and environmental conditions. The extent to which these predictions are influenced by biotic factors such as litter species composition or decomposer activity, and in particular how these different factors interact, is not well understood. In a 5-week laboratory experiment we compared the decomposition of leaf litter from four temperate tree species (Fagus sylvatica, Quercus petraea, Carpinus betulus and Tilia platyphyllos) in response to four interacting factors: elevated CO(2)-induced changes in litter quality, a 3 degrees C warmer environment during decomposition, changes in litter species composition, and presence/absence of a litter-feeding millipede (Glomeris marginata). Elevated CO(2) and temperature had much weaker effects on decomposition than litter species composition and the presence of Glomeris. Mass loss of elevated CO(2)-grown leaf litter was reduced in Fagus and increased in Fagus/Tilia mixtures, but was not affected in any other leaf litter treatment. Warming increased litter mass loss in Carpinus and Tilia, but not in the other two litter species and in none of the mixtures. The CO(2)- and temperature-related differences in decomposition disappeared completely when Glomeris was present. Overall, fauna activity stimulated litter mass loss, but to different degrees depending on litter species composition, with a particularly strong effect on Fagus/Tilia mixtures (+58%). Higher fauna-driven mass loss was not followed by higher C mineralization over the relatively short experimental period. Apart from a strong interaction between litter species composition and fauna, the tested factors had little or no interactive effects on decomposition. We conclude that if global change were to result in substantial shifts in plant community composition and macrofauna abundance in forest ecosystems, these interacting biotic factors could have

  13. Seasonal variation of activity patterns in roe deer in a temperate forested area.

    Science.gov (United States)

    Pagon, Nives; Grignolio, Stefano; Pipia, Anna; Bongi, Paolo; Bertolucci, Cristiano; Apollonio, Marco

    2013-07-01

    We investigated the activity patterns of a European roe deer (Capreolus capreolus) population living in a forested Apennine area in central Italy, in order to shed light on the environmental and biological factors that were expected to account for the observed activity patterns on daily and yearly bases. Daily and seasonal activity patterns of 31 radio-collared roe deer were assessed through sessions of radio tracking for a total period of 18 consecutive months. Roe deer showed bimodal activity patterns throughout the year, with the two highest peaks of activity recorded at dawn and dusk. Activity patterns of males and females differed during the territorial period (from early spring to late summer), whereas they did not during the nonterritorial period. Most likely, behavioral thermoregulation can be held responsible for variation of daily activity patterns in different seasons. In winter, for instance, activity during the dawn period was significantly higher than in other seasons and daylight activity was significantly higher than at night. Nocturnal activity was highest in summer and lowest in winter. During the hunting season, moreover, roe deer showed lower activity levels than during the rest of the year. The prediction that roe deer would show lower activity levels during full moon nights, when the predation risk was assumed to be higher, was not confirmed by our data. Activity rhythms in roe deer were thus subjected to both endogenous and environmental factors, the latter working as exogenous synchronization cues. Accordingly, in changing environmental and ecological conditions, a circadian cycle of activity could be seen as the result of complex interactions among daily behavioral rhythm, digestive physiology, and external modifying factors.

  14. Temperate mountain forest biodiversity under climate change: compensating negative effects by increasing structural complexity.

    Science.gov (United States)

    Braunisch, Veronika; Coppes, Joy; Arlettaz, Raphaël; Suchant, Rudi; Zellweger, Florian; Bollmann, Kurt

    2014-01-01

    Species adapted to cold-climatic mountain environments are expected to face a high risk of range contractions, if not local extinctions under climate change. Yet, the populations of many endothermic species may not be primarily affected by physiological constraints, but indirectly by climate-induced changes of habitat characteristics. In mountain forests, where vertebrate species largely depend on vegetation composition and structure, deteriorating habitat suitability may thus be mitigated or even compensated by habitat management aiming at compositional and structural enhancement. We tested this possibility using four cold-adapted bird species with complementary habitat requirements as model organisms. Based on species data and environmental information collected in 300 1-km2 grid cells distributed across four mountain ranges in central Europe, we investigated (1) how species' occurrence is explained by climate, landscape, and vegetation, (2) to what extent climate change and climate-induced vegetation changes will affect habitat suitability, and (3) whether these changes could be compensated by adaptive habitat management. Species presence was modelled as a function of climate, landscape and vegetation variables under current climate; moreover, vegetation-climate relationships were assessed. The models were extrapolated to the climatic conditions of 2050, assuming the moderate IPCC-scenario A1B, and changes in species' occurrence probability were quantified. Finally, we assessed the maximum increase in occurrence probability that could be achieved by modifying one or multiple vegetation variables under altered climate conditions. Climate variables contributed significantly to explaining species occurrence, and expected climatic changes, as well as climate-induced vegetation trends, decreased the occurrence probability of all four species, particularly at the low-altitudinal margins of their distribution. These effects could be partly compensated by modifying

  15. Temperate mountain forest biodiversity under climate change: compensating negative effects by increasing structural complexity.

    Directory of Open Access Journals (Sweden)

    Veronika Braunisch

    Full Text Available Species adapted to cold-climatic mountain environments are expected to face a high risk of range contractions, if not local extinctions under climate change. Yet, the populations of many endothermic species may not be primarily affected by physiological constraints, but indirectly by climate-induced changes of habitat characteristics. In mountain forests, where vertebrate species largely depend on vegetation composition and structure, deteriorating habitat suitability may thus be mitigated or even compensated by habitat management aiming at compositional and structural enhancement. We tested this possibility using four cold-adapted bird species with complementary habitat requirements as model organisms. Based on species data and environmental information collected in 300 1-km2 grid cells distributed across four mountain ranges in central Europe, we investigated (1 how species' occurrence is explained by climate, landscape, and vegetation, (2 to what extent climate change and climate-induced vegetation changes will affect habitat suitability, and (3 whether these changes could be compensated by adaptive habitat management. Species presence was modelled as a function of climate, landscape and vegetation variables under current climate; moreover, vegetation-climate relationships were assessed. The models were extrapolated to the climatic conditions of 2050, assuming the moderate IPCC-scenario A1B, and changes in species' occurrence probability were quantified. Finally, we assessed the maximum increase in occurrence probability that could be achieved by modifying one or multiple vegetation variables under altered climate conditions. Climate variables contributed significantly to explaining species occurrence, and expected climatic changes, as well as climate-induced vegetation trends, decreased the occurrence probability of all four species, particularly at the low-altitudinal margins of their distribution. These effects could be partly compensated

  16. Ectomycorrhizas in vitro between Tricholoma matsutake, a basidiomycete that associates with Pinaceae, and Betula platyphylla var. japonica, an early-successional birch species, in cool-temperate forests.

    Science.gov (United States)

    Murata, Hitoshi; Yamada, Akiyoshi; Maruyama, Tsuyoshi; Neda, Hitoshi

    2015-04-01

    Tricholoma matsutake is an ectomycorrhizal basidiomycete that associates with Pinaceae in the Northern Hemisphere and produces prized "matsutake" mushrooms. We questioned whether the symbiont could associate with a birch that is an early-successional species in boreal, cool-temperate, or subalpine forests. In the present study, we demonstrated that T. matsutake can form typical ectomycorrhizas with Betula platyphylla var. japonica; the associations included a Hartig net and a thin but distinct fungal sheath, as well as the rhizospheric mycelial aggregate "shiro" that is required for fruiting in nature. The in vitro shiro also emitted a characteristic aroma. This is the first report of an ectomycorrhizal formation between T. matsutake and a deciduous broad-leaved tree in the boreal or cool-temperate zones that T. matsutake naturally inhabits.

  17. Habitats and landscapes associated with bird species in a lowland conifer-dominated ecosystem

    Directory of Open Access Journals (Sweden)

    Edmund J. Zlonis

    2017-06-01

    Full Text Available Human-induced effects on lowland conifer forests in hemiboreal regions are increasing because of expanded use of these northern ecosystems for raw materials, energy, and minerals as well as the potential effects of climatic changes. These forests support many breeding bird species across the Holarctic and allow the persistence of several boreal bird species in hemiboreal and even temperate regions. These bird species are of particular conservation concern as shifting patterns northward in forest composition caused by climate change will likely affect their populations. However, effective management and conservation options are limited because the specifics of these species' breeding habitats are not well understood. We modeled and mapped habitat suitability for 11 species of boreal birds that breed in the lowland conifer forests of the Agassiz Lowlands Ecological Subsection in northern Minnesota and are likely to have reduced breeding habitat in the future: Spruce Grouse (Falcipennis canadensis, Black-backed Woodpecker (Picoides arcticus, Olive-sided Flycatcher (Contopus cooperi, Yellow-bellied Flycatcher (Empidonax flaviventris, Boreal Chickadee (Poecile hudsonicus, Golden-crowned Kinglet (Regulus satrapa, Ruby-crowned Kinglet (Regulus calendula, Swainson's Thrush (Catharus ustulatus, Connecticut Warbler (Oporornis agilis, Palm Warbler (Setophaga palmarum, and Dark-eyed Junco (Junco hyemalis. Sets of 7 to 16 potential environmental covariates, including both stand-level and landscape attributes, were used to develop individual species models. Within this lowland conifer-dominated ecosystem, we found significant selection for specific forest and landscape characteristics by all but one of these species, with the best models including between one and nine variables. Habitat suitability maps were developed from these models and predictions tested with an independent dataset. Model performance depended on species, correctly predicting 56-96% of

  18. Eco-hydrological Controls on Litter Moisture Dynamics in Complex Terrain: Implications for Fuel Moisture and Fire Regimes in Temperate Forests

    Science.gov (United States)

    Nyman, P.; Duff, T. J.; Sheridan, G. J.

    2016-12-01

    Moisture content in litter on the forest floor can control ignition and spread of forest fires. The micrometeorological factors driving variation in litter moisture at the landscape scale are poorly understood, particularly in areas with heterogeneous vegetation and complex terrain. In this research we seek to quantify how climate, vegetation and eco-hydrological feedbacks contribute to variation in net radiation and potential evaporation at the forest floor. Research sites were established at 12 locations in southeast Australia with variable precipitation, solar exposure, and drainage areas. Forests ranged from open woodland to tall temperate forests. We measured solar radiation, air temperature, relative humidity, litter moisture, soil moisture, and litter temperature. Forest structure was characterised using hemispherical photos and LIDAR. Using these data on microclimate and vegetation structure we parameterise a model of daily potential evaporation at the forest floor. Results show that variation in evaporation rates from litter is driven by net radiation and the role of vapour pressure deficit is almost negligible due to high aerodynamic resistance. In open woodlands the net radiation is directly related to short-wave radiation and evaporation remains high despite low temperatures. In the tall wet forests, commonly found along drainage lines and on slopes with polar-facing aspects, the long-wave radiation was just as important as the shortwave radiation. Air temperature is therefore important in determining the flammability of these more productive forests. By implication, in complex terrain with heterogeneous forests, the temperature in the wet parts of the landscape is important in controlling connectivity of fuels and large-scale fire activity.

  19. Community composition of root-associated fungi in a Quercus-dominated temperate forest: “codominance” of mycorrhizal and root-endophytic fungi

    Science.gov (United States)

    Toju, Hirokazu; Yamamoto, Satoshi; Sato, Hirotoshi; Tanabe, Akifumi S; Gilbert, Gregory S; Kadowaki, Kohmei

    2013-01-01

    In terrestrial ecosystems, plant roots are colonized by various clades of mycorrhizal and endophytic fungi. Focused on the root systems of an oak-dominated temperate forest in Japan, we used 454 pyrosequencing to explore how phylogenetically diverse fungi constitute an ecological community of multiple ecotypes. In total, 345 operational taxonomic units (OTUs) of fungi were found from 159 terminal-root samples from 12 plant species occurring in the forest. Due to the dominance of an oak species (Quercus serrata), diverse ectomycorrhizal clades such as Russula, Lactarius, Cortinarius, Tomentella, Amanita, Boletus, and Cenococcum were observed. Unexpectedly, the root-associated fungal community was dominated by root-endophytic ascomycetes in Helotiales, Chaetothyriales, and Rhytismatales. Overall, 55.3% of root samples were colonized by both the commonly observed ascomycetes and ectomycorrhizal fungi; 75.0% of the root samples of the dominant Q. serrata were so cocolonized. Overall, this study revealed that root-associated fungal communities of oak-dominated temperate forests were dominated not only by ectomycorrhizal fungi but also by diverse root endophytes and that potential ecological interactions between the two ecotypes may be important to understand the complex assembly processes of belowground fungal communities. PMID:23762515

  20. Northeastern conifer research: Multiple species and multiple values

    Science.gov (United States)

    Laura S. Kenefic; John C. Brissette; Richard W. Judd

    2014-01-01

    The northern conifer, or spruce-fir, forest of the northeastern USA and adjacent Canada has had a defining influence on the economy and culture of the region. The same can be said of the USDA Forest Service’s research in this forest, which began more than 100 years ago. Forest Service research has evolved since that time in response to changes in the needs and...

  1. Relation of Chlorophyll Fluorescence Sensitive Reflectance Ratios to Carbon FluxMeasurements ofMontanne Grassland and Norway Spruce Forest Ecosystems in the Temperate Zone

    Czech Academy of Sciences Publication Activity Database

    Ač, Alexander; Malenovský, Z.; Urban, Otmar; Hanuš, Jan; Zitová, Martina; Navrátil, M.; Vráblová, M.; Olejníčková, Julie; Špunda, V.; Marek, Michal V.

    2012-01-01

    Roč. 2012, č. 2012 (2012), s. 1-13 ISSN 1537-744X R&D Projects: GA MŽP(CZ) SP/2D1/70/08; GA MŽP(CZ) SP/2D1/93/07; GA MŠk(CZ) LM2010007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional research plan: CEZ:AV0Z60870520 Keywords : Chlorophyll fluorescence * carbon flux * forest ecosystems * Norway Spruce * temperate zone Subject RIV: EH - Ecology, Behaviour Impact factor: 1.730, year: 2012

  2. The Oldest, Slowest Rainforests in the World? Massive Biomass and Slow Carbon Dynamics of Fitzroya cupressoides Temperate Forests in Southern Chile

    Science.gov (United States)

    Urrutia-Jalabert, Rocio; Malhi, Yadvinder; Lara, Antonio

    2015-01-01

    Old-growth temperate rainforests are, per unit area, the largest and most long-lived stores of carbon in the terrestrial biosphere, but their carbon dynamics have rarely been described. The endangered Fitzroya cupressoides forests of southern South America include stands that are probably the oldest dense forest stands in the world, with long-lived trees and high standing biomass. We assess and compare aboveground biomass, and provide the first estimates of net primary productivity (NPP), carbon allocation and mean wood residence time in medium-age stands in the Alerce Costero National Park (AC) in the Coastal Range and in old-growth forests in the Alerce Andino National Park (AA) in the Andean Cordillera. Aboveground live biomass was 113–114 Mg C ha-1 and 448–517 Mg C ha-1 in AC and AA, respectively. Aboveground productivity was 3.35–3.36 Mg C ha-1 year-1 in AC and 2.22–2.54 Mg C ha-1 year-1 in AA, values generally lower than others reported for temperate wet forests worldwide, mainly due to the low woody growth of Fitzroya. NPP was 4.21–4.24 and 3.78–4.10 Mg C ha-1 year-1 in AC and AA, respectively. Estimated mean wood residence time was a minimum of 539–640 years for the whole forest in the Andes and 1368–1393 years for only Fitzroya in this site. Our biomass estimates for the Andes place these ecosystems among the most massive forests in the world. Differences in biomass production between sites seem mostly apparent as differences in allocation rather than productivity. Residence time estimates for Fitzroya are the highest reported for any species and carbon dynamics in these forests are the slowest reported for wet forests worldwide. Although primary productivity is low in Fitzroya forests, they probably act as ongoing biomass carbon sinks on long-term timescales due to their low mortality rates and exceptionally long residence times that allow biomass to be accumulated for millennia. PMID:26353111

  3. The Oldest, Slowest Rainforests in the World? Massive Biomass and Slow Carbon Dynamics of Fitzroya cupressoides Temperate Forests in Southern Chile.

    Directory of Open Access Journals (Sweden)

    Rocio Urrutia-Jalabert

    Full Text Available Old-growth temperate rainforests are, per unit area, the largest and most long-lived stores of carbon in the terrestrial biosphere, but their carbon dynamics have rarely been described. The endangered Fitzroya cupressoides forests of southern South America include stands that are probably the oldest dense forest stands in the world, with long-lived trees and high standing biomass. We assess and compare aboveground biomass, and provide the first estimates of net primary productivity (NPP, carbon allocation and mean wood residence time in medium-age stands in the Alerce Costero National Park (AC in the Coastal Range and in old-growth forests in the Alerce Andino National Park (AA in the Andean Cordillera. Aboveground live biomass was 113-114 Mg C ha(-1 and 448-517 Mg C ha(-1 in AC and AA, respectively. Aboveground productivity was 3.35-3.36 Mg C ha(-1 year(-1 in AC and 2.22-2.54 Mg C ha(-1 year(-1 in AA, values generally lower than others reported for temperate wet forests worldwide, mainly due to the low woody growth of Fitzroya. NPP was 4.21-4.24 and 3.78-4.10 Mg C ha(-1 year(-1 in AC and AA, respectively. Estimated mean wood residence time was a minimum of 539-640 years for the whole forest in the Andes and 1368-1393 years for only Fitzroya in this site. Our biomass estimates for the Andes place these ecosystems among the most massive forests in the world. Differences in biomass production between sites seem mostly apparent as differences in allocation rather than productivity. Residence time estimates for Fitzroya are the highest reported for any species and carbon dynamics in these forests are the slowest reported for wet forests worldwide. Although primary productivity is low in Fitzroya forests, they probably act as ongoing biomass carbon sinks on long-term timescales due to their low mortality rates and exceptionally long residence times that allow biomass to be accumulated for millennia.

  4. Environment vs. Plant Ontogeny: Arthropod Herbivory Patterns on European Beech Leaves along the Vertical Gradient of Temperate Forests in Central Germany

    Directory of Open Access Journals (Sweden)

    Stephanie Stiegel

    2018-01-01

    Full Text Available Environmental and leaf trait effects on herbivory are supposed to vary among different feeding guilds. Herbivores also show variability in their preferences for plant ontogenetic stages. Along the vertical forest gradient, environmental conditions change, and trees represent juvenile and adult individuals in the understorey and canopy, respectively. This study was conducted in ten forests sites in Central Germany for the enrichment of canopy research in temperate forests. Arthropod herbivory of different feeding traces was surveyed on leaves of Fagus sylvatica Linnaeus (European beech; Fagaceae in three strata. Effects of microclimate, leaf traits, and plant ontogenetic stage were analyzed as determining parameters for herbivory. The highest herbivory was caused by exophagous feeding traces. Herbivore attack levels varied along the vertical forest gradient for most feeding traces with distinct patterns. If differences of herbivory levels were present, they only occurred between juvenile and adult F. sylvatica individuals, but not between the lower and upper canopy. In contrast, differences of microclimate and important leaf traits were present between the lower and upper canopy. In conclusion, the plant ontogenetic stage had a stronger effect on herbivory than microclimate or leaf traits along the vertical forest gradient.

  5. Global-Scale Patterns of Forest Fragmentation

    Directory of Open Access Journals (Sweden)

    Kurt Riitters

    2000-12-01

    Full Text Available We report an analysis of forest fragmentation based on 1-km resolution land-cover maps for the globe. Measurements in analysis windows from 81 km 2 (9 x 9 pixels, "small" scale to 59,049 km 2 (243 x 243 pixels, "large" scale were used to characterize the fragmentation around each forested pixel. We identified six categories of fragmentation (interior, perforated, edge, transitional, patch, and undetermined from the amount of forest and its occurrence as adjacent forest pixels. Interior forest exists only at relatively small scales; at larger scales, forests are dominated by edge and patch conditions. At the smallest scale, there were significant differences in fragmentation among continents; within continents, there were significant differences among individual forest types. Tropical rain forest fragmentation was most severe in North America and least severe in Europe-Asia. Forest types with a high percentage of perforated conditions were mainly in North America (five types and Europe-Asia (four types, in both temperate and subtropical regions. Transitional and patch conditions were most common in 11 forest types, of which only a few would be considered as "naturally patchy" (e.g., dry woodland. The five forest types with the highest percentage of interior conditions were in North America; in decreasing order, they were cool rain forest, coniferous, conifer boreal, cool mixed, and cool broadleaf.

  6. Impacts of extreme weather events and climate variability on carbon exchanges in an age-sequence of managed temperate pine forests from 2003 to 201

    Science.gov (United States)

    Arain, M. A.

    2017-12-01

    North American temperate forests are a critical component of the global carbon cycle and regional water resources. A large portion of these forests has traditionally been managed for timber production and other uses. The response of these forests, which are in different stages of development, to extreme weather events such as drought and heat stresses, climate variability and management regimes is not fully understood. In this study, eddy covariance flux measurements in an age sequence (77-, 42-, and 14-years old as of 2016) of white pine (Pinus strobus L.) plantation forests in southern Ontario, Canada are examined to determine the impact of heat and drought stresses and climate variability over a 14 year period (2003 to 2016). The mean annual net ecosystem productivity (NEP) values were 195 ± 87, 512 ±161 and 103 ± 103 g C m-2 year-1 in 77-, 42- and 14-year-old forests respectively, over the study period. The youngest forest became a net carbon sink in the fifth year of its growth. Air temperature was a dominant control on carbon fluxes and heat stress reduced photosynthesis much more as compared to ecosystem respiration in the growing season. A large decrease in annual NEP was observed during years experiencing heat waves. Drought stress had the strongest impact on the middle age forest which had the largest carbon sink and water demand. In contrast, young forest was more sensitive to heat stress, than drought. Severity of heat and drought stress impacts was highly dependent on the timing of these events. Simultaneous occurrence of heat and drought stress in the early growing season such as in 2012 and 2016 had a drastic negative impact on carbon balance in these forests due to plant-soil-atmosphere feedbacks. Future research should consider the timing of the extreme events, the stage of forest development and effects of extreme events on component fluxes. This research helps to assess the vulnerability of managed forests and their ecological and hydrological

  7. CHANGES IN MICROBIAL AND PHYSICOCHEMICAL SOIL PROPERTIES ASSOCIATE WITH CHARCOAL PRODUCTION IN TEMPERATE FOREST (QUERCUS SPP IN SANTA ROSA, GTO. MEXICO.

    Directory of Open Access Journals (Sweden)

    Blanca Estela Gómez Luna

    2010-05-01

    Full Text Available The temperate forest of Quercus spp. Santa Rosa is one ofthe most extensive forests in central Mexico. In this forest,charcoal is produced traditionally by rural communities.This study evaluated the impact of the activity of charcoalproduction in three sampling sites of the forest, soil fromthe impact site, land adjacent to the site of charcoalproduction and control soil without charcoal productionactivity on physicochemical and microbiological properties.We determined pH, concentration of macro-and microelementswas performed by calculating microbial colonyforming units (CFU of bacteria, fungi, actinomycetes andpromoting growth of plants rhizobacteria (PGPR. Finally,we determined microbial biomass by fumigation-incubationmethod. On the floor of coal production, an increase in pH,the concentration of cations forming bases (Ca2 + and K+and a high regard microbial fungi, bacteria andactinomycetes, but the microbial biomass and organicmatter content was higher in the control soil, in terms ofRPCP only isolated in the soil adjacent to coal productionsite and the control soil. The physicochemical changesproduced by the warming effect of soil significantlyaffected the microbial community favoring the reduction orelimination of dominant groups sensitive to hightemperatures that are actively involved in the dynamics ofsoil processes

  8. Bat and bird diversity along independent gradients of latitude and tree composition in European forests.

    Science.gov (United States)

    Charbonnier, Yohan M; Barbaro, Luc; Barnagaud, Jean-Yves; Ampoorter, Evy; Nezan, Julien; Verheyen, Kris; Jactel, Hervé

    2016-10-01

    Species assemblages are shaped by local and continental-scale processes that are seldom investigated together, due to the lack of surveys along independent gradients of latitude and habitat types. Our study investigated changes in the effects of forest composition and structure on bat and bird diversity across Europe. We compared the taxonomic and functional diversity of bat and bird assemblages in 209 mature forest plots spread along gradients of forest composition and vertical structure, replicated in 6 regions spanning from the Mediterranean to the boreal biomes. Species richness and functional evenness of both bat and bird communities were affected by the interactions between latitude and forest composition and structure. Bat and bird species richness increased with broadleaved tree cover in temperate and especially in boreal regions but not in the Mediterranean where they increased with conifer abundance. Bat species richness was lower in forests with smaller trees and denser understorey only in northern regions. Bird species richness was not affected by forest structure. Bird functional evenness increased in younger and denser forests. Bat functional evenness was also influenced by interactions between latitude and understorey structure, increasing in temperate forests but decreasing in the Mediterranean. Covariation between bat and bird abundances also shifted across Europe, from negative in southern forests to positive in northern forests. Our results suggest that community assembly processes in bats and birds of European forests are predominantly driven by abundance and accessibility of feeding resources, i.e., insect prey, and their changes across both forest types and latitudes.

  9. Seasonal changes in the photosynthetic capacity and chlorophyll fluorescence in canopy leaves of Quercus crispula in a cool-temperate forest

    Science.gov (United States)

    Tsujimoto, K.; Kato, T.; Nakaji, T.

    2016-12-01

    As well as a proxy of ecosystem level photosynthesis, sun-induced fluorescence (SIF) is expected to be an indicator of plant physiological information in photosynthesis (Frankenberg et al., 2011). Zhang et al. (2014) especially suggested that the SIF can be used to estimate the capacity of RuBP carboxylation, Vcmax, at the ecosystem scale by the simple inversion approach with the combination of both observation and modeling. However, the seasonal pattern of the relationships between SIF and such gas exchange physiological parameters has not been confirmed by the direct field observation, yet. Here, we present the field observation results of both gas exchange based photosynthetic parameters and fluorescence properties of canopy leaves of Japanese oak (Quercus crispula) in a cool-temperate forest. In the Tomakomai experimental forest site (42°40'N, 141°36'E), Hokkaido University in Japan, we conducted the periodical measurements of the seasonality in photosynthetic parameters (Li-6400, Li-Cor, USA) and LED-induced fluorescence yield (USB4000, OceanOptics, USA and mini-PAM, WALZ, Germany) from June to October in 2016. Every two or three weeks, the in-situ single leaf data were collected for 10-16 leaves (consisting of 3-4 leaves x 3-4 individual trees) of Japanese oak at the top of canopy at 15-20m above ground surface with approaching by the tall canopy crane. After the in-situ data acquisition, the leaves are frozen in liquid nitrogen immediately followed by removable from shoots, and are going to be analyzed their chemical properties (ex. Chla, Chlb etc.). By analyzing seasonal pattern of those leaf traits, we are going to show how effectively the chlorophyll fluorescence can assess the carbon assimilation capacity of cool temperate forest.

  10. Thirty year change in lodgepole and lodgepole/mixed conifer forest structure following 1980s mountain pine beetle outbreak in western Colorado, USA

    Science.gov (United States)

    Kristen A. Pelz; Frederick W. Smith

    2012-01-01

    Current mortality in lodgepole pine caused by mountain pine beetle (MPB) throughout much of western North America has resulted in concern about future forest structure. To better understand the long-term effects of the current mortality, and how it might differ depending on forest species composition, we measured forest vegetation and woody fuel accumulations...

  11. Dominant effect of increasing forest biomass on evapotranspiration: interpretations of movement in Budyko space

    Directory of Open Access Journals (Sweden)

    F. Jaramillo

    2018-01-01

    Full Text Available During the last 6 decades, forest biomass has increased in Sweden mainly due to forest management, with a possible increasing effect on evapotranspiration. However, increasing global CO2 concentrations may also trigger physiological water-saving responses in broadleaf tree species, and to a lesser degree in some needleleaf conifer species, inducing an opposite effect. Additionally, changes in other forest attributes may also affect evapotranspiration. In this study, we aimed to detect the dominating effect(s of forest change on evapotranspiration by studying changes in the ratio of actual evapotranspiration to precipitation, known as the evaporative ratio, during the period 1961–2012. We first used the Budyko framework of water and energy availability at the basin scale to study the hydroclimatic movements in Budyko space of 65 temperate and boreal basins during this period. We found that movements in Budyko space could not be explained by climatic changes in precipitation and potential evapotranspiration in 60 % of these basins, suggesting the existence of other dominant drivers of hydroclimatic change. In both the temperate and boreal basin groups studied, a negative climatic effect on the evaporative ratio was counteracted by a positive residual effect. The positive residual effect occurred along with increasing standing forest biomass in the temperate and boreal basin groups, increasing forest cover in the temperate basin group and no apparent changes in forest species composition in any group. From the three forest attributes, standing forest biomass was the one that could explain most of the variance of the residual effect in both basin groups. These results further suggest that the water-saving response to increasing CO2 in these forests is either negligible or overridden by the opposite effect of the increasing forest biomass. Thus, we conclude that increasing standing forest biomass is the dominant driver of long-term and large

  12. Dominant effect of increasing forest biomass on evapotranspiration: interpretations of movement in Budyko space

    Science.gov (United States)

    Jaramillo, Fernando; Cory, Neil; Arheimer, Berit; Laudon, Hjalmar; van der Velde, Ype; Hasper, Thomas B.; Teutschbein, Claudia; Uddling, Johan

    2018-01-01

    During the last 6 decades, forest biomass has increased in Sweden mainly due to forest management, with a possible increasing effect on evapotranspiration. However, increasing global CO2 concentrations may also trigger physiological water-saving responses in broadleaf tree species, and to a lesser degree in some needleleaf conifer species, inducing an opposite effect. Additionally, changes in other forest attributes may also affect evapotranspiration. In this study, we aimed to detect the dominating effect(s) of forest change on evapotranspiration by studying changes in the ratio of actual evapotranspiration to precipitation, known as the evaporative ratio, during the period 1961-2012. We first used the Budyko framework of water and energy availability at the basin scale to study the hydroclimatic movements in Budyko space of 65 temperate and boreal basins during this period. We found that movements in Budyko space could not be explained by climatic changes in precipitation and potential evapotranspiration in 60 % of these basins, suggesting the existence of other dominant drivers of hydroclimatic change. In both the temperate and boreal basin groups studied, a negative climatic effect on the evaporative ratio was counteracted by a positive residual effect. The positive residual effect occurred along with increasing standing forest biomass in the temperate and boreal basin groups, increasing forest cover in the temperate basin group and no apparent changes in forest species composition in any group. From the three forest attributes, standing forest biomass was the one that could explain most of the variance of the residual effect in both basin groups. These results further suggest that the water-saving response to increasing CO2 in these forests is either negligible or overridden by the opposite effect of the increasing forest biomass. Thus, we conclude that increasing standing forest biomass is the dominant driver of long-term and large-scale evapotranspiration

  13. Recovery trajectories of kelp forest animals are rapid yet spatially variable across a network of temperate marine protected areas

    OpenAIRE

    Caselle, JE; Rassweiler, A; Hamilton, SL; Warner, RR

    2015-01-01

    © 2015, Nature Publishing Group. All rights reserved. Oceans currently face a variety of threats, requiring ecosystem-based approaches to management such as networks of marine protected areas (MPAs). We evaluated changes in fish biomass on temperate rocky reefs over the decade following implementation of a network of MPAs in the northern Channel Islands, California. We found that the biomass of targeted (i.e. fished) species has increased consistently inside all MPAs in the network, with an e...

  14. Biomass and morphology of fine roots in temperate broad-leaved forests differing in tree species diversity: is there evidence of below-ground overyielding?

    Science.gov (United States)

    Meinen, Catharina; Hertel, Dietrich; Leuschner, Christoph

    2009-08-01

    Biodiversity effects on ecosystem functioning in forests have only recently attracted increasing attention. The vast majority of studies in forests have focused on above-ground responses to differences in tree species diversity, while systematic analyses of the effects of biodiversity on root systems are virtually non-existent. By investigating the fine root systems in 12 temperate deciduous forest stands in Central Europe, we tested the hypotheses that (1) stand fine root biomass increases with tree diversity, and (2) 'below-ground overyielding' of species-rich stands in terms of fine root biomass is the consequence of spatial niche segregation of the roots of different species. The selected stands represent a gradient in tree species diversity on similar bedrock from almost pure beech forests to medium-diverse forests built by beech, ash, and lime, and highly-diverse stands dominated by beech, ash, lime, maple, and hornbeam. We investigated fine root biomass and necromass at 24 profiles per stand and analyzed species differences in fine root morphology by microscopic analysis. Fine root biomass ranged from 440 to 480 g m(-2) in the species-poor to species-rich stands, with 63-77% being concentrated in the upper 20 cm of the soil. In contradiction to our two hypotheses, the differences in tree species diversity affected neither stand fine root biomass nor vertical root distribution patterns. Fine root morphology showed marked distinctions between species, but these root morphological differences did not lead to significant differences in fine root surface area or root tip number on a stand area basis. Moreover, differences in species composition of the stands did not alter fine root morphology of the species. We conclude that 'below-ground overyielding' in terms of fine root biomass does not occur in the species-rich stands, which is most likely caused by the absence of significant spatial segregation of the root systems of these late-successional species.

  15. Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae) in a mature Asian temperate forest ecosystem.

    Science.gov (United States)

    Zou, Yi; Sang, Weiguo; Bai, Fan; Axmacher, Jan Christoph

    2013-01-01

    A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae) as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.

  16. Relationships between plant diversity and the abundance and α-diversity of predatory ground beetles (Coleoptera: Carabidae in a mature Asian temperate forest ecosystem.

    Directory of Open Access Journals (Sweden)

    Yi Zou

    Full Text Available A positive relationship between plant diversity and both abundance and diversity of predatory arthropods is postulated by the Enemies Hypothesis, a central ecological top-down control hypothesis. It has been supported by experimental studies and investigations of agricultural and grassland ecosystems, while evidence from more complex mature forest ecosystems is limited. Our study was conducted on Changbai Mountain in one of the last remaining large pristine temperate forest environments in China. We used predatory ground beetles (Coleoptera: Carabidae as target taxon to establish the relationship between phytodiversity and their activity abundance and diversity. Results showed that elevation was the only variable included in both models predicting carabid activity abundance and α-diversity. Shrub diversity was negatively and herb diversity positively correlated with beetle abundance, while shrub diversity was positively correlated with beetle α-diversity. Within the different forest types, a negative relationship between plant diversity and carabid activity abundance was observed, which stands in direct contrast to the Enemies Hypothesis. Furthermore, plant species density did not predict carabid α-diversity. In addition, the density of herbs, which is commonly believed to influence carabid movement, had little impact on the beetle activity abundance recorded on Changbai Mountain. Our study indicates that in a relatively large and heterogeneous mature forest area, relationships between plant and carabid diversity are driven by variations in environmental factors linked with altitudinal change. In addition, traditional top-down control theories that are suitable in explaining diversity patterns in ecosystems of low diversity appear to play a much less pronounced role in highly complex forest ecosystems.

  17. Long-Term Effects of White-Tailed Deer Exclusion on the Invasion of Exotic Plants: A Case Study in a Mid-Atlantic Temperate Forest.

    Directory of Open Access Journals (Sweden)

    Xiaoli Shen

    Full Text Available Exotic plant invasions and chronic high levels of herbivory are two of the major biotic stressors impacting temperate forest ecosystems in eastern North America, and the two problems are often linked. We used a 4-ha deer exclosure maintained since 1991 to examine the influence of a generalist herbivore, white-tailed deer (Odocoileus virginianus, on the abundance of four exotic invasive (Rosa multiflora, Berberis thunbergii, Rubus phoenicolasius and Microstegium vimineum and one native (Cynoglossum virginianum plant species, within a 25.6-ha mature temperate forest dynamics plot in Virginia, USA. We identified significant predictors of the abundance of each focal species using generalized linear models incorporating 10 environmental and landscape variables. After controlling for those predictors, we applied our models to a 4-ha deer exclusion site and a 4-ha reference site, both embedded within the larger plot, to test the role of deer on the abundance of the focal species. Slope, edge effects and soil pH were the most frequent predictors of the abundance of the focal species on the larger plot. The abundance of C. virginianum, known to be deer-dispersed, was significantly lower in the exclosure. Similar patterns were detected for B. thunbergii, R. phoenicolasius and M. vimineum, whereas R. multiflora was more abundant within the exclosure. Our results indicate that chronic high deer density facilitates increased abundances of several exotic invasive plant species, with the notable exception of R. multiflora. We infer that the invasion of many exotic plant species that are browse-tolerant to white-tailed deer could be limited by reducing deer populations.

  18. Diversity patterns of ground beetles and understory vegetation in mature, secondary, and plantation forest regions of temperate northern China

    NARCIS (Netherlands)

    Zou, Yi; Sang, Weiguo; Wang, Shunzhong; Warren-Thomas, Eleanor; Liu, Yunhui; Yu, Zhenrong; Wang, Changliu; Axmacher, Jan Christoph

    2015-01-01

    Plantation and secondary forests form increasingly important components of the global forest cover, but our current knowledge about their potential contribution to biodiversity conservation is limited. We surveyed understory plant and carabid species assemblages at three distinct regions in

  19. Dynamics of a temperate deciduous forest under landscape-scale management: Implications for adaptability to climate change

    Science.gov (United States)

    Matthew G. Olson; Benjamin O. Knapp; John M. Kabrick

    2017-01-01

    Landscape forest management is an approach to meeting diverse objectives that collectively span multiple spatial scales. It is critical that we understand the long-term effects of landscape management on the structure and composition of forest tree communities to ensure that these practices are sustainable. Furthermore, it is increasingly important to also consider...

  20. Comparison of soil organic matter dynamics at five temperate deciduous forests with physical fractionation and radiocarbon measurements

    Science.gov (United States)

    Karis J. McFarlane; Margaret S. Torn; Paul J. Hanson; Rachel C. Porras; Christopher W. Swanston; Mac A. Callaham; Thomas P. Guilderson

    2013-01-01

    Forest soils represent a significant pool for carbon sequestration and storage, but the factors controlling soil carbon cycling are not well constrained.We compared soil carbon dynamics at five broadleaf forests in the Eastern US that vary in climate, soil type, and soil ecology: two sites at the University of Michigan Biological Station (MI-Coarse, sandy;MI-Fine,...

  1. Solar Radiation Determines Site Occupancy of Coexisting Tropical and Temperate Deer Species Introduced to New Zealand Forests.

    Directory of Open Access Journals (Sweden)

    Robert B Allen

    Full Text Available Assemblages of introduced taxa provide an opportunity to understand how abiotic and biotic factors shape habitat use by coexisting species. We tested hypotheses about habitat selection by two deer species recently introduced to New Zealand's temperate rainforests. We hypothesised that, due to different thermoregulatory abilities, rusa deer (Cervus timorensis; a tropical species would prefer warmer locations in winter than red deer (Cervus elaphus scoticus; a temperate species. Since adult male rusa deer are aggressive in winter (the rut, we also hypothesised that rusa deer and red deer would not use the same winter locations. Finally, we hypothesised that in summer both species would prefer locations with fertile soils that supported more plant species preferred as food. We used a 250 × 250 m grid of 25 remote cameras to collect images in a 100-ha montane study area over two winters and summers. Plant composition, solar radiation, and soil fertility were also determined for each camera location. Multiseason occupancy models revealed that direct solar radiation was the best predictor of occupancy and detection probabilities for rusa deer in winter. Multistate, multiseason occupancy models provided strong evidence that the detection probability of adult male rusa deer was greater in winter and when other rusa deer were present at a location. Red deer mostly vacated the study area in winter. For the one season that had sufficient camera images of both species (summer 2011 to allow two-species occupancy models to be fitted, the detection probability of rusa deer also increased with solar radiation. Detection probability also varied with plant composition for both deer species. We conclude that habitat use by coexisting tropical and temperate deer species in New Zealand likely depends on the interplay between the thermoregulatory and behavioural traits of the deer and the abiotic and biotic features of the habitat.

  2. Fire, competition and forest pests: landscape treatment to sustain ecosystem function

    Science.gov (United States)

    Geral I. McDonald; A. E. Harvey; J. R. Tonn

    2000-01-01

    Fire, competition for light and water, and native forest pests have interacted for millennia in western forests to produce a countryside dominated by seral species of conifers. These conifer-dominated ecosystems exist in six kinds of biotic communities. We divided one of these communities, the Rocky Mountain Montane Conifer Forest, into 31 subseries based on the...

  3. Response of Quercus velutina growth and water use efficiency to climate variability and nitrogen fertilization in a temperate deciduous forest in the northeastern USA.

    Science.gov (United States)

    Jennings, Katie A; Guerrieri, Rossella; Vadeboncoeur, Matthew A; Asbjornsen, Heidi

    2016-04-01

    Nitrogen (N) deposition and changing climate patterns in the northeastern USA can influence forest productivity through effects on plant nutrient relations and water use. This study evaluates the combined effects of N fertilization, climate and rising atmospheric CO2on tree growth and ecophysiology in a temperate deciduous forest. Tree ring widths and stable carbon (δ(13)C) and oxygen (δ(18)O) isotopes were used to assess tree growth (basal area increment, BAI) and intrinsic water use efficiency (iWUE) ofQuercus velutinaLamb., the dominant tree species in a 20+ year N fertilization experiment at Harvard Forest (MA, USA). We found that fertilized trees exhibited a pronounced and sustained growth enhancement relative to control trees, with the low- and high-N treatments responding similarly. All treatments exhibited improved iWUE over the study period (1984-2011). Intrinsic water use efficiency trends in the control trees were primarily driven by changes in stomatal conductance, while a stimulation in photosynthesis, supported by an increase in foliar %N, contributed to enhancing iWUE in fertilized trees. All treatments were predominantly influenced by growing season vapor pressure deficit (VPD), with BAI responding most strongly to early season VPD and iWUE responding most strongly to late season VPD. Nitrogen fertilization increasedQ. velutinasensitivity to July temperature and precipitation. Combined, these results suggest that ambient N deposition in N-limited northeastern US forests has enhanced tree growth over the past 30 years, while rising ambient CO2has improved iWUE, with N fertilization and CO2having synergistic effects on iWUE. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  4. Estimating and Up-Scaling Fuel Moisture and Leaf Dry Matter Content of a Temperate Humid Forest Using Multi Resolution Remote Sensing Data

    Directory of Open Access Journals (Sweden)

    Hamed Adab

    2016-11-01

    Full Text Available Vegetation moisture and dry matter content are important indicators in predicting the behavior of fire and it is widely used in fire spread models. In this study, leaf fuel moisture content such as Live Fuel Moisture Content (LFMC, Leaf Relative Water Content (RWC, Dead Fuel Moisture Content (DFMC, and Leaf Dry Matter Content (LDMC (hereinafter known as moisture content indices (MCI were calculated in the field for different forest species at 32 sites in a temperate humid forest (Zaringol forest located in northeastern Iran. These data and several relevant vegetation-biophysical indices and atmospheric variables calculated using Landsat 7 Enhanced Thematic Mapper Plus (ETM+ data with moderate spatial resolution (30 m were used to estimate MCI of the Zaringol forest using Artificial Neural Network (ANN and Multiple Linear Regression (MLR methods. The prediction of MCI using ANN showed that ETM+ predicted MCI slightly better (Mean Absolute Percentage Error (MAPE of 6%–12% than MLR (MAPE between 8% and 17%. Once satisfactory results in estimating MCI were obtained by using ANN from ETM+ data, these data were then upscaled to estimate MCI using MODIS data for daily monitoring of leaf water and leaf dry matter content at 500 m spatial resolution. For MODIS derived LFMC, LDMC, RWC, and DLMC, the ANN produced a MAPE between 11% and 29% for the indices compared to MLR which produced an MAPE of 14%–33%. In conclusion, we suggest that upscaling is necessary for solving the scale discrepancy problems between the indicators and low spatial resolution MODIS data. The scaling up of MCI could be used for pre-fire alert system and thereby can detect fire prone areas in near real time for fire-fighting operations.

  5. Conifer woods from the Salamanca Formation (early Paleocene), Central Patagonia, Argentina: Paleoenvironmental implications

    Science.gov (United States)

    Ruiz, Daniela P.; Brea, Mariana; Raigemborn, M. Sol; Matheos, Sergio D.

    2017-07-01

    The main objective of the present work is to describe the first conifer assemblage of a mixed forest from the Danian Salamanca Formation at the Estancia Las Violetas locality (San Jorge Basin, Central Patagonia, Argentina), based on detailed descriptions of secondary xylem. Also, sedimentological description of the Estancia Las Violetas outcrops are made in order to understand the paleoenvironmental conditions under which paleocommunities developed. Six conifer woods are described and assigned to one Podocarpoxylon Gothan and three Cupressinoxylon Göppert species (including a new species). This is the first record of Patagonia forest where the conifer assemblage is dominated by Cupressinoxylon, associated with Podocarpaceae and palms (recorded as fruits), conforming a mixed forest with a floristic composition similar to present-day New Caledonia forests. Las Violetas fossil forest represent a parautochtonous community developed in a forested coastal setting, a tide-dominated estuary, at ∼51-50° S paleolatitudes of South America during the early-middle Danian.

  6. Modeling Carbon Storage across a Heterogeneous Mixed Temperate Forest: The Influence of Forest Type Specificity on Regional-scale Carbon Storage Estimates

    Science.gov (United States)

    Adams, A.; Pontius, J.; Galford, G. L.; Gudex-Cross, D.; Merrill, S.

    2017-12-01

    Accurately assessing forest carbon storage is critical to understanding global carbon cycles and the effects of land cover changes on ecological processes. However, calculations of regional-scale forest carbon storage typically rely on maps that reflect only broad forest classes. How species-specific differences in carbon storage may affect assessments of forest carbon in heterogeneous forests is largely unexplored. We used new maps of tree species relative basal area, degraded to various levels of species composition specificity, to examine whether species-specific information improves the accuracy of forest carbon estimates in the northeastern U.S. The forest classification schemes tested, from highest to lowest specificity, were: 1) relative basal area by species, 2) species association classes, and 3) general forest types per IPCC (2006) guidelines. The level of forest type specificity did influence results. Generally, lower carbon storage estimates were generated by models using higher-specificity forest classifications. The two most specific models, with mean carbon storage values of 102-107 Mg/ha, were the most accurate compared to field validation plots and best reflected the finer resolution spatial pattern of carbon storage across the landscape. Northeastern forests may be storing more carbon than previously thought; our species-specific regional estimates are higher than both U.S. Forest Service-generated estimates (84-90 Mg C/ha) and IPCC carbon storage guideline best estimates (75 Mg C/ha). Our results suggest that considering carbon storage capacities of different tree species can improve accuracy of carbon assessments, and better reflect carbon storage patterns across heterogeneous landscapes. However, stand age heavily influences carbon storage values, and more work is needed to improve landscape-scale stand age data.

  7. Influences of evergreen gymnosperm and deciduous angiosperm tree species on the functioning of temperate and boreal forests

    DEFF Research Database (Denmark)

    Augusto, Laurent; De Schrijver, An; Vesterdal, Lars

    2015-01-01

    that distinguish litter decomposition rates of EGs from DAs. Although it has been suggested that DAs can result in higher accumulation of soil carbon stocks, evidence from field studies does not show any obvious trend. Further research is required to clarify if accumulation of carbon in soils (i.e. forest floor+mineral...... is usually similar or lower in DA stands than in stands of EGs. Aboveground production of dead organic matter appears to be of the same order of magnitude between tree species groups growing on the same site. Some DAs induce more rapid decomposition of litter than EGs because of the chemical properties...... of their tissues, higher soil moisture and favourable conditions for earthworms. Forest floors consequently tend to be thicker in EG forests compared to DA forests. Many factors, such as litter lignin content, influence litter decomposition and it is difficult to identify specific litter-quality parameters...

  8. Dispersal and group formation dynamics in a rare and endangered temperate forest bat (Nyctalus lasiopterus,Chiroptera: Vespertilionidae).

    Science.gov (United States)

    Santos, João D; Meyer, Christoph F J; Ibáñez, Carlos; Popa-Lisseanu, Ana G; Juste, Javier

    2016-11-01

    For elusive mammals like bats, colonization of new areas and colony formation are poorly understood, as is their relationship with the genetic structure of populations. Understanding dispersal and group formation behaviors is critical not only for a better comprehension of mammalian social dynamics, but also for guiding conservation efforts of rare and endangered species. Using nuclear and mitochondrial markers, we studied patterns of genetic diversity and differentiation among and within breeding colonies of giant noctule bats ( Nyctalus lasiopterus ), their relation to a new colony still in formation, and the impact of this ongoing process on the regionwide genetic makeup. Nuclear differentiation among colonies was relatively low and mostly nonsignificant. Mitochondrial variation followed this pattern, contrasting with findings for other temperate bat species. Our results suggest that this may indicate a recent population expansion. On average, female giant noctules were not more closely related to other colony members than to foreign individuals. This was also true for members of the newly forming colony and those of another, older group sampled shortly after its formation, suggesting that contrary to findings for other temperate bats, giant noctule colonies are not founded by relatives. However, mother-daughter pairs were found in the same populations more often than expected under random dispersal. Given this indication of philopatry, the lack of mitochondrial differentiation among most colonies in the region is probably due to the combination of a recent population expansion and group formation events.

  9. Temper Tantrums

    Science.gov (United States)

    ... whining and crying to screaming, kicking, hitting, and breath holding. They're equally common in boys and girls ... Child's Preschool Teacher Your Child's Habits Separation Anxiety Breath-Holding Spells Train Your Temper View more Partner Message ...

  10. Influence of light and soil moisture on Sierran mixed-conifer understory communities.

    Science.gov (United States)

    Malcolm North; Brian Oakley; Rob Fiegener; Andrew Gray; Michael. Barbour

    2005-01-01

    Sierra Nevada forests have high understory species richness yet we do not know which site factors influence herb and shrub distribution or abundance. We examined the understory of an old-growth mixed-conifer Sierran forest and its distribution in relation to microsite conditions. The forest has high species richness (98 species sampled), most of which are herbs with...

  11. Diterpene resin acids in conifers.

    Science.gov (United States)

    Keeling, Christopher I; Bohlmann, Jörg

    2006-11-01

    Diterpene resin acids are a significant component of conifer oleoresin, which is a viscous mixture of terpenoids present constitutively or inducibly upon herbivore or pathogen attack and comprises one form of chemical resistance to such attacks. This review focuses on the recent discoveries in the chemistry, biosynthesis, molecular biology, regulation, and biology of these compounds in conifers.

  12. Comprehensive ecosystem model-experiment synthesis using multiple datasets at two temperate forest free-air CO2 enrichment experiments: model performance and compensating biases

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Anthony P [ORNL; Hanson, Paul J [ORNL; DeKauwe, Martin G [Macquarie University; Medlyn, Belinda [Macquarie University; Zaehle, S [Max Planck Institute for Biogeochemistry; Asao, Shinichi [Colorado State University, Fort Collins; Dietze, Michael [University of Illinois, Urbana-Champaign; Hickler, Thomas [Goethe University, Frankfurt, Germany; Huntinford, Chris [Centre for Ecology and Hydrology, Wallingford, United Kingdom; Iversen, Colleen M [ORNL; Jain, Atul [University of Illinois, Urbana-Champaign; Lomas, Mark [University of Sheffield; Luo, Yiqi [University of Oklahoma; McCarthy, Heather R [Duke University; Parton, William [Colorado State University, Fort Collins; Prentice, I. Collin [Macquarie University; Thornton, Peter E [ORNL; Wang, Shusen [Canada Centre for Remote Sensing (CCRS); Wang, Yingping [CSIRO Marine and Atmospheric Research; Warlind, David [Lund University, Sweden; Weng, Ensheng [University of Oklahoma, Norman; Warren, Jeffrey [ORNL; Woodward, F. Ian [University of Sheffield; Oren, Ram [Duke University; Norby, Richard J [ORNL

    2014-01-01

    Free Air CO2 Enrichment (FACE) experiments provide a remarkable wealth of data to test the sensitivities of terrestrial ecosystem models (TEMs). In this study, a broad set of 11 TEMs were compared to 22 years of data from two contrasting FACE experiments in temperate forests of the south eastern US the evergreen Duke Forest and the deciduous Oak Ridge forest. We evaluated the models' ability to reproduce observed net primary productivity (NPP), transpiration and Leaf Area index (LAI) in ambient CO2 treatments. Encouragingly, many models simulated annual NPP and transpiration within observed uncertainty. Daily transpiration model errors were often related to errors in leaf area phenology and peak LAI. Our analysis demonstrates that the simulation of LAI often drives the simulation of transpiration and hence there is a need to adopt the most appropriate of hypothesis driven methods to simulate and predict LAI. Of the three competing hypotheses determining peak LAI (1) optimisation to maximise carbon export, (2) increasing SLA with canopy depth and (3) the pipe model the pipe model produced LAI closest to the observations. Modelled phenology was either prescribed or based on broader empirical calibrations to climate. In some cases, simulation accuracy was achieved through compensating biases in component variables. For example, NPP accuracy was sometimes achieved with counter-balancing biases in nitrogen use efficiency and nitrogen uptake. Combined analysis of parallel measurements aides the identification of offsetting biases; without which over-confidence in model abilities to predict ecosystem function may emerge, potentially leading to erroneous predictions of change under future climates.