WorldWideScience

Sample records for undisturbed forest growth

  1. Carbon Exchange Processes In A Old-Growth Undisturbed Boreal Forest In Northern Sweden

    Science.gov (United States)

    Lindroth, A.; Heliasz, M.; Mölder, M.; Holst, J.

    2015-12-01

    It has been a common and long lasting view that old-growth forests are carbon neutral, i.e., the uptake of CO2 by gross photosynthesis is equal to the release of the same amount through ecosystem respiration. This hypothesis was originally developed by Odum based on theoretical reasoning on the balance between stability and diversity in ecosystems and how this relationship shifted with succession over time. At that time, the theory was underpinned by a relatively scarce empirical material but later supported by the observed decline in net primary productivity (NPP) with increasing stand age. More recently, based on direct measurements of net ecosystem exchange (NEE) Luyssaert et al. showed that old-growth forests still were significant sinks for atmospheric carbon dioxide thus challenging the hypothesis that old forests are in balance with respect to uptake and emission of CO2. Most of the forests in Luyssaert et al. analyses were temperate and semi-arid boreal forests and only few were located in the humid boreal zone. In order to shed light on this issue we initiated in 2011 carbon exchange studies in an old (>200 years) undisturbed humid boreal forest in Northern Sweden using EC measurements of NEE and chamber measurements of soil effluxes. The results indicate that the forest is a small sink of CO2 in the order of 20 g C m-2 y-1. The forest floor vegetation contributes significantly to GPP, in the order of 25-40%, depending on time of season. The nighttime ecosystem respiration showed a weak increase with air temperature up to about 15 ºC and then it started to decrease. The reason for this decrease that occurred at a relatively low temperature is still unclear. The small annual sink of -20 g C m-2 observed here is similar in magnitude to changes in soil carbon content on nearby much older forests located on small islands which has not been disturbed for several hundreds of years. Our study thus confirms that old forests can continue to take up carbon although

  2. 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).

  3. Necromass in undisturbed and logged forests in the Brazilian Amazon.

    Science.gov (United States)

    Michael Palace; Michael Keller; Gregory P. Asner; Jose Natalino M. Silva; Carlos. Passos

    2007-01-01

    Necromass is an important stock of carbon in tropical forests. We estimated volume, density, and mass of fallen and standing necromass in undisturbed and selectively logged forests at Juruena, Mato Grosso, Brazil (10.488S, 58.478W). We also measured standing dead trees at the Tapajos National Forest, Para, Brazil (3.088S, 54.948W) complementing our earlier study there...

  4. Necromass production: studies in undisturbed and logged Amazon Forests

    Science.gov (United States)

    MICHAEL PALACE; MICHAEL KELLER; HUDSON SILVA

    2008-01-01

    Necromass stocks account for up to 20% of carbon stored in tropical forests and have been estimated to be 14–19% of the annual aboveground carbon flux. Both stocks and fluxes of necromass are infrequently measured. In this study, we directly measured the production of fallen coarse necromass (>2 cm diameter) during 4.5 years using repeated surveys in undisturbed...

  5. Estimate of biomass and carbon pools in disturbed and undisturbed oak forests in Tunisia

    Directory of Open Access Journals (Sweden)

    Lobna Zribi

    2016-07-01

    Full Text Available Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (regenerated after a tornado and an aged cork oak forest (undisturbed forest as well as its distribution among the different pools (tree, litter and soil. Area of study. The north west of Tunisia Material and methods. Carbon stocks were evaluated in the above and belowground cork oak trees, the litter and the 150 cm of the soil. Tree biomass was estimated in both young and aged forests using allometric biomass equations developed for wood stem, cork stem, wood branch, cork branch, leaves, roots and total tree biomass based on combinations of diameter at breast height, total height and crown length as independent variables. Main results. Total tree biomass in forests was 240.58 Mg ha-1 in the young forest and 411.30 Mg ha-1 in the aged forest with a low root/shoot ratio (0.41 for young forest and 0.31 for aged forest. Total stored carbon was 419.46 Mg C ha-1 in the young forest and 658.09 Mg C ha-1 in the aged forest. Carbon stock (Mg C ha-1 was estimated to be113.61(27.08% and 194.08 (29.49% in trees, 3.55 (0.85% and 5.73 (0.87% in litter and 302.30 (72.07% and 458.27 (69.64% in soil in the young and aged forests, respectively. Research highlights. Aged undisturbed forest had the largest tree biomass but a lower potential for accumulation of carbon in the future; in contrast, young disturbed forest had both higher growth and carbon storage potential. Keywords: Tree biomass; disturbance; allometry; cork oak forests; soil organic carbon stock.

  6. Estimate of biomass and carbon pools in disturbed and undisturbed oak forests in Tunisia

    Energy Technology Data Exchange (ETDEWEB)

    Zribi, L.; Chaar, H.; Khaldi, A.; Henchi, B.; Mouillot, F.; Gharbi, F.

    2016-07-01

    Aim of the study. To estimate biomass and carbon accumulation in a young and disturbed forest (regenerated after a tornado) and an aged cork oak forest (undisturbed forest) as well as its distribution among the different pools (tree, litter and soil). Area of study. The north west of Tunisia. Material and methods. Carbon stocks were evaluated in the above and belowground cork oak trees, the litter and the 150 cm of the soil. Tree biomass was estimated in both young and aged forests using allometric biomass equations developed for wood stem, cork stem, wood branch, cork branch, leaves, roots and total tree biomass based on combinations of diameter at breast height, total height and crown length as independent variables. Main results. Total tree biomass in forests was 240.58 Mg ha-1 in the young forest and 411.30 Mg ha-1 in the aged forest with a low root/shoot ratio (0.41 for young forest and 0.31 for aged forest). Total stored carbon was 419.46 Mg C ha-1 in the young forest and 658.09 Mg C ha-1 in the aged forest. Carbon stock (Mg C ha-1) was estimated to be113.61(27.08%) and 194.08 (29.49%) in trees, 3.55 (0.85%) and 5.73 (0.87%) in litter and 302.30 (72.07%) and 458.27 (69.64%) in soil in the young and aged forests, respectively. Research highlights. Aged undisturbed forest had the largest tree biomass but a lower potential for accumulation of carbon in the future; in contrast, young disturbed forest had both higher growth and carbon storage potential. (Author)

  7. Long-term changes in liana abundance and forest dynamics in undisturbed Amazonian forests.

    Science.gov (United States)

    Laurance, William F; Andrade, Ana S; Magrach, Ainhoa; Camargo, José L C; Valsko, Jefferson J; Campbell, Mason; Fearnside, Philip M; Edwards, Will; Lovejoy, Thomas E; Laurance, Susan G

    2014-06-01

    Lianas (climbing woody vines) are important structural parasites of tropical trees and may be increasing in abundance in response to global-change drivers. We assessed long-term (-14-year) changes in liana abundance and forest dynamics within 36 1-ha permanent plots spanning -600 km2 of undisturbed rainforest in central Amazonia. Within each plot, we counted each liana stem (> or = 2 cm diameter) and measured its diameter at 1.3 m height, and then used these data to estimate liana aboveground biomass. An initial liana survey was completed in 1997-1999 and then repeated in 2012, using identical methods. Liana abundance in the plots increased by an average of 1.00% +/- 0.88% per year, leading to a highly significant (t = 6.58, df = 35, P rainfall and forest dynamics from our study site to test hypotheses about potential drivers of change in liana communities. Lianas generally increase with rainfall seasonality, but we found no significant trends over time (1997-2012) in five rainfall parameters (total annual rainfall, dry-season rainfall, wet-season rainfall, number of very dry months, CV of monthly rainfall). However, rates of tree mortality and recruitment have increased significantly over time in our plots, and general linear mixed-effect models suggested that lianas were more abundant at sites with higher tree mortality and flatter topography. Rising concentrations of atmospheric CO2, which may stimulate liana growth, might also have promoted liana increases. Our findings clearly support the view that lianas are increasing in abundance in old-growth tropical forests, possibly in response to accelerating forest dynamics and rising CO2 concentrations. The aboveground biomass of trees was lowest in plots with abundant lianas, suggesting that lianas could reduce forest carbon storage and potentially alter forest dynamics if they continue to proliferate.

  8. LBA-ECO ND-11 Regeneration in Undisturbed and Logged Forests, NW Mato Grosso, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set reports the results of field surveys to determine: regeneration diversity and size distribution of plants in primary undisturbed forest; and...

  9. LBA-ECO TG-07 Tree Geometry in an Undisturbed Forest in Cauaxi, Para, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — Canopy measurements in an undisturbed eastern Amazon forest (Cauxi, Para, Brazil. See Figure 1) were derived from a one-time event in 2000 using a hand-held laser...

  10. LBA-ECO ND-11 Regeneration in Undisturbed and Logged Forests, NW Mato Grosso, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set reports the results of field surveys to determine: regeneration diversity and size distribution of plants in primary undisturbed forest; and...

  11. LBA-ECO TG-07 Tree Geometry in an Undisturbed Forest in Cauaxi, Para, Brazil

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Canopy measurements in an undisturbed eastern Amazon forest (Cauxi, Para, Brazil. See Figure 1) were derived from a one-time event in 2000 using a...

  12. Coarse woody debris in undisturbed and logged forests in the eastern Brazilian Amazon.

    Science.gov (United States)

    Michael Keller; Michael Palace; Gregory P. Asner; Rodrigo Jr. Pereira; Jose Natalino M. Silva

    2004-01-01

    Coarse woody debris (CWD) is an important component of the carbon cycle in tropical forests. We measured the volume and density of fallen CWD at two sites, Cauaxi and Tapajós in the Eastern Amazon. At both sites we studied undisturbed forests (UFs) and logged forests 1 year after harvest. Conventional logging (CL) and reduced impact logging (RIL) were...

  13. Distribution of tree species in an undisturbed northern hardwood-spruce-fir forest, the Bowl, N. H.

    Science.gov (United States)

    C. Wayne Martin

    1977-01-01

    Knowledge acquired from forests that have never been logged can provide clues to the long-term effects of resource utilization. In 1974, a survey was made of the vegetation of the Bowl Research Natural Area in central New Hampshire, known to be undisturbed by humans; and an adjacent watershed known to have been logged in the late 1880's. There were no significant...

  14. Production of alkaline cellulase by fungi isolated from an undisturbed rain forest of peru.

    Science.gov (United States)

    Vega, Karin; Villena, Gretty K; Sarmiento, Victor H; Ludeña, Yvette; Vera, Nadia; Gutiérrez-Correa, Marcel

    2012-01-01

    Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL(-1)) with higher specific productivities (>30 U g(-1) h(-1)). Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry.

  15. Production of Alkaline Cellulase by Fungi Isolated from an Undisturbed Rain Forest of Peru

    Directory of Open Access Journals (Sweden)

    Karin Vega

    2012-01-01

    Full Text Available Alkaline cellulase producing fungi were isolated from soils of an undisturbed rain forest of Peru. The soil dilution plate method was used for the enumeration and isolation of fast growing cellulolytic fungi on an enriched selective medium. Eleven out of 50 different morphological colonies were finally selected by using the plate clearing assay with CMC as substrate at different pH values. All 11 strains produced cellulases in liquid culture with activities at alkaline pH values without an apparent decrease of them indicating that they are true alkaline cellulase producers. Aspergillus sp. LM-HP32, Penicillium sp. LM-HP33, and Penicillium sp. LM-HP37 were the best producers of FP cellulase (>3 U mL−1 with higher specific productivities (>30 U g−1 h−1. Three strains have been found suitable for developing processes for alkaline cellulase production. Soils from Amazonian rain forests are good sources of industrial fungi with particular characteristics. The results of the present study are of commercial and biological interest. Alkaline cellulases may be used in the polishing and washing of denim processing of the textile industry.

  16. Small scale temporal distribution of radiocesium in undisturbed coniferous forest soil: Radiocesium depth distribution profiles.

    Science.gov (United States)

    Teramage, Mengistu T; Onda, Yuichi; Kato, Hiroaki

    2016-04-01

    The depth distribution of pre-Fukushima and Fukushima-derived (137)Cs in undisturbed coniferous forest soil was investigated at four sampling dates from nine months to 18 months after the Fukushima nuclear power plant accident. The migration rate and short-term temporal variability among the sampling profiles were evaluated. Taking the time elapsed since the peak deposition of pre-Fukushima (137)Cs and the median depth of the peaks, its downward displacement rates ranged from 0.15 to 0.67 mm yr(-1) with a mean of 0.46 ± 0.25 mm yr(-1). On the other hand, in each examined profile considerable amount of the Fukushima-derived (137)Cs was found in the organic layer (51%-92%). At this moment, the effect of time-distance on the downward distribution of Fukushima-derived (137)Cs seems invisible as its large portion is still found in layers where organic matter is maximal. This indicates that organic matter seems the primary and preferential sorbent of radiocesium that could be associated with the physical blockage of the exchanging sites by organic-rich dusts that act as a buffer against downward propagation of radiocesium, implying radiocesium to be remained in the root zone for considerable time period. As a result, this soil section can be a potential source of radiation dose largely due to high radiocesium concentration coupled with its low density. Generally, such kind of information will be useful to establish a dynamic safety-focused decision support system to ease and assist management actions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. SOM and Biomass C Stocks in Degraded and Undisturbed Andean and Coastal Nothofagus Forests of Southwestern South America

    Directory of Open Access Journals (Sweden)

    Francis Dube

    2016-12-01

    Full Text Available Grazing and over-exploitation can severely degrade soil in native forests. Considering that productivity in ecosystems is related to soil organic matter (SOM content and quality, the objectives of this study were to: (1 determine the influence of degraded (DEF, partly-degraded (PDF, and undisturbed (UNF Nothofagus forests on the stocks of carbon (C in tree biomass and SOM; (2 evaluate fractions of SOM as indicators of sustainable management; and (3 use the Century model to determine the potential gains of soil organic C (SOC. The forests are located in the Andes and Coastal mountains of southern Chile. The SOM was fractionated to separate the light fraction (LF, macroaggregates (>212 µm, mesoaggregates (212–53 µm, and microaggregates (<53 µm. In two measurement periods, the SOC stocks at 0–20 cm and 20–40 cm depths in macroaggregates were on average 100% higher in the Andean UNF, and SOC was over twice as much at 20–40 cm depth in Andean DEF. Century simulations showed that improved silvopastoral management would gradually increase total SOC in degraded soils of both sites, especially the Ultisol with a 15% increase between 2016 and 2216 (vs. 7% in the Andisol. Greater SOC in macroaggregates (p < 0.05 of UNF indicate a condition of higher sustainability and better management over the years.

  18. Dynamics of Leishmania chagasi infection in small mammals of the undisturbed and degraded tropical dry forests of northern Colombia.

    Science.gov (United States)

    Travi, B L; Osorio, Y; Becerra, M T; Adler, G H

    1998-01-01

    The infection rate with Leishmania chagasi and the population dynamics of small mammals were studied in an undisturbed forest reserve (Colosó) and an area of highly degraded forest (San Andrés de Sotavento [SAS]) in northern Colombia, both endemic for visceral leishmaniasis. Live trapping of mammals was done every month, and species, age, sex and reproductive status determined. L. chagasi was detected in samples of skin or spleen by the polymerase chain reaction, after extraction of deoxyribonucleic acid using specific primers (DB8/AJS3), and dot blood hybridization. Didelphis marsupialis was found to be infected in Colosó (3/21, 14.3%) and SAS (13/137, 9.5%); its relative abundance was higher in SAS (93/113, 82% of the captures). Although Proechimys canicollis was also found to be infected in Colosó (3/34, 8.8%) and SAS (2/4), its relative abundance was much lower (4%) in SAS than in Colosó (56% of 77 animals captured). Sciurus granatensis, Marmosa robinsoni, Heteromys anomalus, Zygodontomys brevicauda and Metachirus nudicaudatus were less common, and no L. chagasi infection was detected in them.

  19. Aboveground Biomass and Carbon Stocks of an Undisturbed Regenerating Sal (Shorea Robusta Gaertn. F. Forest Of Goalpara District, Assam, Northeast India

    Directory of Open Access Journals (Sweden)

    Debajit Rabha

    2014-12-01

    Full Text Available The present paper deals with the above ground biomass and carbon stocks of an undisturbed Sal forest of Goalpara district, Assam, Northeast India. The average AGB and C were recorded 239.45 ± 12.8 Mg ha-1 and 119.73 ± 6.4 Mg ha-1. Density distribution curve indicates the high carbon sequestration potential of the stand in near future which further helps in climate change mitigation. Currently, conservation measures are well imposed in combine effort of local community and government. Legal involvement of local community in conservation exercises along with the forest department might be very effective in management of Sal forests.DOI: http://dx.doi.org/10.3126/ije.v3i4.11743   International Journal of EnvironmentVolume-3, Issue-4, Sep-Nov 2014Page: 147-155 

  20. LBA-ECO TG-07 Trace Gas Fluxes, Undisturbed and Logged Sites, Para, Brazil: 2000-2002

    Science.gov (United States)

    M.M. Keller; R.K. Varner; J.D. Dias; H.S. Silva; P.M. Crill; Jr. de Oliveira; G.P. Asner

    2009-01-01

    Trace gas fluxes of carbon dioxide, methane, nitrous oxide, and nitric oxide were measured manually at undisturbed and logged forest sites in the Tapajos National Forest, near Santarem, Para, Brazil. Manual measurements were made approximately weekly at both the undisturbed and logged sites. Fluxes from clay and sand soils were completed at the undisturbed sites....

  1. Growth and Bioproductivity of Urban Forests

    OpenAIRE

    Lakyda, I.

    2012-01-01

    This paper provides information about the background, process and results of growth modeling, yield and bioproductivity of artificial (planted) pine stands in urban forests in the city of Kyiv. This topic is exceptionally important to ecological functions of urban forest ecosystems around Kyiv, like any other urban forests, in terms of maintaining sustainability of the internal environment of cities, improving the environmental situation and reducing harmful effects of industry, transport, et...

  2. The relative contributions of forest growth and areal expansion to forest biomass carbon

    Science.gov (United States)

    P. Li; J. Zhu; H. Hu; Z. Guo; Y. Pan; R. Birdsey; J. Fang

    2016-01-01

    Forests play a leading role in regional and global terrestrial carbon (C) cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area) and forest growth (increase in biomass density). Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms...

  3. Forest evaporation models: Relationships between stand growth and evaporation

    CSIR Research Space (South Africa)

    Le Maitre, David C

    1997-06-01

    Full Text Available The relationships between forest stand structure, growth and evaporation were analysed to determine whether forest evaporation can be estimated from stand growth data. This approach permits rapid assessment of the potential impacts of afforestation...

  4. Ecological characteristics of old-growth Douglas-fir forests.

    Science.gov (United States)

    Jerry F. Franklin; Kermit Jr. Cromack; William Denison; Arthur McKee; Chris Maser; James Sedell; Fred Swanson; Glen. Juday

    1981-01-01

    Old-growth coniferous forests differ significantly from young-growth forests in species composition, function (rate and paths of energy flow and nutrient and water cycling), and structure. Most differences can be related to four key structural components of old growth: large live trees, large snags, large logs on land, and large logs in streams. Foresters wishing to...

  5. Internal equilibrium layer growth over forest

    DEFF Research Database (Denmark)

    Dellwik, E.; Jensen, N.O.

    2000-01-01

    the magnitude of the scatter. Different theoretical friction velocity profiles for the Internal Boundary Layer (IBL) are tested against the forest data. The results yield information on the Internal Equilibrium Layer (IEL) growth and an equation for the IEL height fur neutral conditions is derived. For stable...... conditions the results indicate that very long fetches are required in order to measure parameters in equilibrium with the actual surface....

  6. Climate and Management Controls on Forest Growth and Forest Carbon Balance in the Western United States

    Science.gov (United States)

    Kelsey, Katharine Cashman

    Climate change is resulting in a number of rapid changes in forests worldwide. Forests comprise a critical component of the global carbon cycle, and therefore climate-induced changes in forest carbon balance have the potential to create a feedback within the global carbon cycle and affect future trajectories of climate change. In order to further understanding of climate-driven changes in forest carbon balance, I (1) develop a method to improve spatial estimates forest carbon stocks, (2) investigate the effect of climate change and forest management actions on forest recovery and carbon balance following disturbance, and (3) explore the relationship between climate and forest growth, and identify climate-driven trends in forest growth through time, within San Juan National Forest in southwest Colorado, USA. I find that forest carbon estimates based on texture analysis from LandsatTM imagery improve regional forest carbon maps, and this method is particularly useful for estimating carbon stocks in forested regions affected by disturbance. Forest recovery from disturbance is also a critical component of future forest carbon stocks, and my results indicate that both climate and forest management actions have important implications for forest recovery and carbon dynamics following disturbance. Specifically, forest treatments that use woody biomass removed from the forest for electricity production can reduce carbon emissions to the atmosphere, but climate driven changes in fire severity and forest recovery can have the opposite effect on forest carbon stocks. In addition to the effects of disturbance and recovery on forest condition, I also find that climate change is decreasing rates of forest growth in some species, likely in response to warming summer temperatures. These growth declines could result in changes of vegetation composition, or in extreme cases, a shift in vegetation type that would alter forest carbon storage. This work provides insight into both

  7. Acid deposition effects on forest composition and growth on the Monongahela National Forest, West Virginia

    Science.gov (United States)

    P.E. Elias; J.A. Burger; M.B. Adams

    2009-01-01

    The northern and central Appalachian forests are subject to high levels of atmospheric acid deposition (AD), which has been shown in some forests to negatively impact forest growth as well as predispose the forest system to damage from secondary stresses. The purpose of this study was to evaluate the possible contribution of AD to changes in composition and...

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

    Science.gov (United States)

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Ecosystem level studies identify plant soil feed backs as important controls on soil nutrient availability,particularly for nitrogen and phosphorus. Although site and species specific studies of tree species soil relationships are relatively common,comparatively fewer studies consider multiple coexisting speciesin old-growth forests across a range of sites that vary underlying soil fertility. We characterized patterns in forest floor and mineral soil nutrients associated with four common tree species across eight undisturbed old-growth forests in Oregon, USA, and used two complementary conceptual models to assess tree species soil relationships. Plant soil feedbacks that could reinforce sitelevel differences in nutrient availability were assessed using the context dependent relationships model, where by relative species based differences in each soil nutrient divergedorconvergedas nutrient status changed across sites. Tree species soil relationships that did not reflect strong feedbacks were evaluated using a site independent relationships model, where by forest floor and surface mineral soil nutrient tools differed consistently by tree species across sites,without variation in deeper mineral soils. We found that theorganically cycled elements carbon, nitrogen, and phosphorus exhibited context-dependent differences among species in both forest floor and mineral soil, and most of ten followed adivergence model,where by species differences were greatest at high-nutrient sites. These patterns are consistent with the oryemphasizing biotic control of these elements through plant soil feedback mechanisms. Site independent species differences were strongest for pool so if the weather able cations calcium, magnesium, potassium,as well as phosphorus, in mineral soils. Site independent species differences in forest floor nutrients we reattributable too nespecies that displayed significant greater forest floor mass accumulation. Our finding confirmed that site-independent and

  9. An Old-Growth Definition for Southwestern Subtropical Upland Forests

    Science.gov (United States)

    David D. Diamond

    1998-01-01

    Mainly evergreen, broad-leaved forests in the Southwestern United States are restricted to the Lower Rio Grande Valley of Texas. The soils and long growing season make this region valuable cropland, and, thus, almost all of the area once occupied by this forest type has been converted to row crops. Remaining old-growth forests are usually dominated by some combination...

  10. Area of old-growth forests in California, Oregon, and Washington. Forest Service research bulletin

    Energy Technology Data Exchange (ETDEWEB)

    Bolsinger, C.L.; Waddell, K.L.

    1993-12-01

    An area of old-growth forests in California, Oregon, and Washington has declined significantly in the second half of the 20th century. The report summarizes available information on old-growth forest area by ownership in California, Oregon, and Washington. Old-growth definitions used by the various owners and agencies are provided.

  11. Hydrodynamic erosion process of undisturbed clay

    NARCIS (Netherlands)

    Zhao, G.; Visser, P.J.; Vrijling, J.K.

    2011-01-01

    This paper describes the hydrodynamic erosion process of undisturbed clay due to the turbulent flow, based on theoretical analysis and experimental results. The undisturbed clay has the unique and complicated characteristics of cohesive force among clay particles, which are highly different from

  12. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics

    Science.gov (United States)

    Itter, Malcolm S.; Finley, Andrew O.; D'Amato, Anthony W.; Foster, Jane R.; Bradford, John B.

    2017-01-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  13. Comparison of an empirical forest growth and yield simulator and a forest gap simulator using actual 30-year growth from two even-aged forests in Kentucky

    Science.gov (United States)

    Daniel A. Yaussy

    2000-01-01

    Two individual-tree growth simulators are used to predict the growth and mortality on a 30-year-old forest site and an 80-year-old forest site in eastern Kentucky. The empirical growth and yield model (NE-TWIGS) was developed to simulate short-term (

  14. Ninety-two years of tree growth and death in a second-growth redwood forest

    Science.gov (United States)

    Benjamin G. Iberle; Stephen C. Sillett; Robert Van Pelt; Mark Andre

    2017-01-01

    Mature second-growth redwood (Sequoia sempervirens (D. Don) Endl.) forests are an important and uncommon resource in the redwood region. Development of second-growth redwood forests beyond rotation age is not well understood. Continuous long-term data are especially lacking, considering that the maximum possible age of second-growth stands is now...

  15. Growth characteristics of two tropical forest species Warburgia ...

    African Journals Online (AJOL)

    Growth parameters for seedlings of two forest trees, Warburgia ugandensis and Polyscias fulva, were measured under various light growth conditions. Leaf area and plant height were significantly higher under low light (< 42% full sunlight) than high light (65% of sunlight) growth conditions (P<0.001). Plant leaf area ranged ...

  16. Analyzing growth and mortality in a subtropical urban forest ecosystem

    Science.gov (United States)

    Alicia B. Lawrence; Fancisco J. Escobedo; Christina L. Staudhammera; Wayne Zipperer Zipperer

    2012-01-01

    Information on urban tree growth, mortality and in-growth is currently being used to estimate urban forest structure changes and ecosystem services such as carbon sequestration. This study reports on tree diameter growth and mortality in 65 plots distributed among four land use categories, which were established in 2005/2006 in Gainesville, Florida, USA and were re-...

  17. Growth characteristics of two tropical forest species Warburgia ...

    African Journals Online (AJOL)

    Administrator

    2008-01-11

    Jan 11, 2008 ... Growth parameters for seedlings of two forest trees, Warburgia ugandensis and Polyscias fulva, were measured under various light growth conditions. Leaf area and plant height were significantly higher under low light (< 42% full sunlight) than high light (65% of sunlight) growth conditions (P<0.001). Plant.

  18. LBA-ECO TG-07 Trace Gas Fluxes, Undisturbed and Logged Sites, Para, Brazil: 2000-2002

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Trace gas fluxes of carbon dioxide, methane, nitrous oxide, and nitric oxide were measured manually at undisturbed and logged forest sites in the Tapajos...

  19. Growth and yield model application in tropical rain forest management

    Science.gov (United States)

    James Atta-Boateng; John W., Jr. Moser

    2000-01-01

    Analytical tools are needed to evaluate the impact of management policies on the sustainable use of rain forest. Optimal decisions concerning the level of management inputs require accurate predictions of output at all relevant input levels. Using growth data from 40 l-hectare permanent plots obtained from the semi-deciduous forest of Ghana, a system of 77 differential...

  20. Relictual amphibians and old-growth forest

    Science.gov (United States)

    H.H. Welsh

    1990-01-01

    Terrestrial and aquatic herpetofauna were sampled by pitfall traps, time-constrained searches, and areaconstrained searches (stream sites only) over a three-year period to examine the importance of forest age to amphibians and reptiles. Fifty-four terrestrial and 39 aquatic sites in Douglas-fir-dominated, mixed evergreen forests were located in southwestern Oregon and...

  1. DRAINMOD-FOREST: Integrated modeling of hydrology, soil carbon and nitrogen dynamics, and plant growth for drained forests

    Science.gov (United States)

    Shiying Tian; Mohamed A. Youssef; R. Wayne Skaggs; Devendra M. Amatya; G.M. Chescheir

    2012-01-01

    We present a hybrid and stand-level forest ecosystem model, DRAINMOD-FOREST, for simulating the hydrology, carbon (C) and nitrogen (N) dynamics, and tree growth for drained forest lands under common silvicultural practices. The model was developed by linking DRAINMOD, the hydrological model, and DRAINMOD-N II, the soil C and N dynamics model, to a forest growth model,...

  2. Observed forest sensitivity to climate implies large changes in 21st century North American forest growth.

    Science.gov (United States)

    Charney, Noah D; Babst, Flurin; Poulter, Benjamin; Record, Sydne; Trouet, Valerie M; Frank, David; Enquist, Brian J; Evans, Margaret E K

    2016-09-01

    Predicting long-term trends in forest growth requires accurate characterisation of how the relationship between forest productivity and climatic stress varies across climatic regimes. Using a network of over two million tree-ring observations spanning North America and a space-for-time substitution methodology, we forecast climate impacts on future forest growth. We explored differing scenarios of increased water-use efficiency (WUE) due to CO2 -fertilisation, which we simulated as increased effective precipitation. In our forecasts: (1) climate change negatively impacted forest growth rates in the interior west and positively impacted forest growth along the western, southeastern and northeastern coasts; (2) shifting climate sensitivities offset positive effects of warming on high-latitude forests, leaving no evidence for continued 'boreal greening'; and (3) it took a 72% WUE enhancement to compensate for continentally averaged growth declines under RCP 8.5. Our results highlight the importance of locally adapted forest management strategies to handle regional differences in growth responses to climate change. © 2016 John Wiley & Sons Ltd/CNRS.

  3. Solute Diffusivity in Undisturbed Soil

    DEFF Research Database (Denmark)

    Lægdsmand, Mette K.; Møldrup, Per; Schjønning, Per

    2012-01-01

    diffusivities independent of the tracer set used. We analyzed the whole data set using Archie's law and found a linear relation between Archie's exponent and the logarithm of the soil water matric suction in centimeters of water (pF). An analysis of seven data sets from the literature showed......Solute diffusivity in soil plays a major role in many important processes with relation to plant growth and environmental issues. Soil solute diffusivity is affected by the volumetric water content as well as the morphological characteristics of water-filled pores. The solute diffusivity in intact...... soil samples from two different tillage treatments (soil from below the depth of a harrow treatment and soil from within a moldboard plowed plow layer) was estimated based on concentration profiles using a newly developed method. The method makes use of multiple tracers (two sets of counterdiffusing...

  4. Assessment of soil acidification effects on forest growth in Sweden

    International Nuclear Information System (INIS)

    Sverdrup, H.; Warfvinge, P.; Nihlgaard, B.

    1994-01-01

    The results of mapping critical loads, areas where they have been exceeded and steady state (Ca+Mg+K)/Al ratios of soils in Sweden, has been used to assess the order of magnitude of the ecological and economic risks involved with acid deposition for Swedish forests. The results of the calculations indicate that 81% of the Swedish forested area received acid deposition in excess of the critical load at present. Under continued deposition at 1990 level, forest die-back is predicted to occur on approximately 1% of the forested area, and significant growth rate reductions are predicted for 80% of the Swedish forested area. For Sweden, growth losses in the order of 17.5 million m -3 yr -1 are predicted, equivalent to approximately 19% of current growth. Comparable losses can be predicted for other Nordic countries. The soil acidification situation is predicted to deteriorate significantly during the next 5-15 years, unless rapid emission reductions can be achieved. A minimum deposition reduction over Sweden of 95% on sulphur deposition and 30% on the N deposition in relation to 1990 level is required in order to protect 95% of the Swedish forest ecosystems from adverse effects of acidification. A minimum reduction of 60% on sulphur deposition and 30% on the N deposition is required to keep forest harvest at planned levels. 148 refs., 9 figs., 9 tabs

  5. Growth rates of important East African montane forest trees, with ...

    African Journals Online (AJOL)

    These trees showed growth rates at least twice as high as those of the primary species. Juniperus procera was found to be the fastest growing species in the cedar forest, underlining its success in forming dense stands after a fire. Only young Podocarpus latifolius showed a similar fast growth. Olea europaea ssp. cuspidata, ...

  6. Direct observation of morphological evolution of a catalyst during carbon nanotube forest growth: new insights into growth and growth termination

    Science.gov (United States)

    Jeong, Seojeong; Lee, Jaegeun; Kim, Hwan-Chul; Hwang, Jun Yeon; Ku, Bon-Cheol; Zakharov, Dmitri N.; Maruyama, Benji; Stach, Eric A.; Kim, Seung Min

    2016-01-01

    In this study, we develop a new methodology for transmission electron microscopy (TEM) analysis that enables us to directly investigate the interface between carbon nanotube (CNT) arrays and the catalyst and support layers for CNT forest growth without any damage induced by a post-growth TEM sample preparation. Using this methodology, we perform in situ and ex situ TEM investigations on the evolution of the morphology of the catalyst particles and observe the catalyst particles to climb up through CNT arrays during CNT forest growth. We speculate that the lifted catalysts significantly affect the growth and growth termination of CNT forests along with Ostwald ripening and sub-surface diffusion. Thus, we propose a modified growth termination model which better explains various phenomena related to the growth and growth termination of CNT forests.In this study, we develop a new methodology for transmission electron microscopy (TEM) analysis that enables us to directly investigate the interface between carbon nanotube (CNT) arrays and the catalyst and support layers for CNT forest growth without any damage induced by a post-growth TEM sample preparation. Using this methodology, we perform in situ and ex situ TEM investigations on the evolution of the morphology of the catalyst particles and observe the catalyst particles to climb up through CNT arrays during CNT forest growth. We speculate that the lifted catalysts significantly affect the growth and growth termination of CNT forests along with Ostwald ripening and sub-surface diffusion. Thus, we propose a modified growth termination model which better explains various phenomena related to the growth and growth termination of CNT forests. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr05547d

  7. Carbon changes in conterminous US forests associated with growth and major disturbances: 1992-2001

    Science.gov (United States)

    Daolan Zheng; Linda S. Heath; Mark J. Ducey; James E. Smith

    2011-01-01

    We estimated forest area and carbon changes in the conterminous United States using a remote sensing based land cover change map, forest fire data from the Monitoring Trends in Burn Severity program, and forest growth and harvest data from the USDA Forest Service, Forest Inventory and Analysis Program. Natural and human-associated disturbances reduced the forest...

  8. Facilitative-competitive interactions in an old-growth forest: the importance of large-diameter trees as benefactors and stimulators for forest community assembly.

    Directory of Open Access Journals (Sweden)

    Andreas Fichtner

    Full Text Available The role of competition in tree communities is increasingly well understood, while little is known about the patterns and mechanisms of the interplay between above- and belowground competition in tree communities. This knowledge, however, is crucial for a better understanding of community dynamics and developing adaptive near-natural management strategies. We assessed neighbourhood interactions in an unmanaged old-growth European beech (Fagus sylvatica forest by quantifying variation in the intensity of above- (shading and belowground competition (crowding among dominant and co-dominant canopy beech trees during tree maturation. Shading had on average a much larger impact on radial growth than crowding and the sensitivity to changes in competitive conditions was lowest for crowding effects. We found that each mode of competition reduced the effect of the other. Increasing crowding reduced the negative effect of shading, and at high levels of shading, crowding actually had a facilitative effect and increased growth. Our study demonstrates that complementarity in above- and belowground processes enable F. sylvatica to alter resource acquisition strategies, thus optimising tree radial growth. As a result, competition seemed to become less important in stands with a high growing stock and tree communities with a long continuity of anthropogenic undisturbed population dynamics. We suggest that growth rates do not exclusively depend on the density of potential competitors at the intraspecific level, but on the conspecific aggregation of large-diameter trees and their functional role for regulating biotic filtering processes. This finding highlights the potential importance of the rarely examined relationship between the spatial aggregation pattern of large-diameter trees and the outcome of neighbourhood interactions, which may be central to community dynamics and the related forest ecosystem services.

  9. Comparative physiology of a central hardwood old-growth forest canopy and forest gap

    Science.gov (United States)

    A. R. Gillespie; J. Waterman; K. Saylors

    1993-01-01

    Concerns of poor oak regeneration, changing climate, biodiversity patterns, and carbon cycling in the Central Hardwoods have prompted ecological and physiological studies of old-growth forests and their role in maintaining the landscape. To examine the effects of old-growth canopy structure on the physiological productivity of overstory and understory species, we...

  10. Carbon Uptake and Storage in Old-Growth and Second-Growth Forests in Central Vermont

    Science.gov (United States)

    Lloyd, A. H.; Weisser, O.

    2013-12-01

    Managing forests towards the goal of maximizing carbon uptake and storage provides an important tool for climate change mitigation. There is significant spatial and temporal variation among forests, even within an ecosystem type, in annual uptake and storage of carbon. Understanding the causes for that variation is important in refining management practices and restoration goals that promote carbon storage. We explore the variation in carbon storage and uptake among forests differing in age in central Vermont, comparing young, intermediate-aged, and old-growth forests. We generally expected that younger forests would have a higher annual uptake of carbon than older forests. Significant uncertainty exists, however, about the temporal trajectory from a young, rapidly growing forest to an old-growth forest that may be in a steady-state, with no net uptake of carbon. Within each forest, we compare differences among functional groups of species (e.g., hardwoods versus softwoods) in contribution to overall forest carbon uptake and storage. Our study sites include an old-growth hemlock/mixed hardwood forest that has not been directly affected by human activities, and which contains trees upwards of 350 years old; a 130-year-old mixed hardwood forest that has recolonized former pasture land; and a 90-year-old mixed hardwood forest on formerly agricultural floodplain land. Carbon storage in live and dead biomass pools was estimated from allometric equations, based on repeated measurements of tree diameters in permanently marked study plots. Historical patterns of carbon storage in living biomass were estimated by reconstructing tree diameter from measured increment cores, and then estimating the living biomass in each year. As expected, the old-growth forest stored almost twice the C in live biomass as the two second-growth forests, which stored equivalent amounts of carbon, despite the difference in age. Dead biomass was a larger pool of C in the old-growth forest than in

  11. Biodiversity promotes tree growth during succession in subtropical forest.

    Directory of Open Access Journals (Sweden)

    Martin Barrufol

    Full Text Available Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental manipulations of tree diversity will take decades to yield final results. To date, biodiversity effects in natural forests therefore have only been reported from sample surveys or meta-analyses with plots not initially selected for diversity. We studied biomass and growth of subtropical forests stands in southeastern China. Taking advantage of variation in species recruitment during secondary succession, we adopted a comparative study design selecting forest plots to span a gradient in species richness. We repeatedly censored the stem diameter of two tree size cohorts, comprising 93 species belonging to 57 genera and 33 families. Tree size and growth were analyzed in dependence of species richness, the functional diversity of growth-related traits, and phylogenetic diversity, using both general linear and structural equation modeling. Successional age covaried with diversity, but differently so in the two size cohorts. Plot-level stem basal area and growth were positively related with species richness, while growth was negatively related to successional age. The productivity increase in species-rich, functionally and phylogenetically diverse plots was driven by both larger mean sizes and larger numbers of trees. The biodiversity effects we report exceed those from experimental studies, sample surveys and meta-analyses, suggesting that subtropical tree diversity is an important driver of forest productivity and re-growth after disturbance that supports the provision of ecological services by these ecosystems.

  12. Biodiversity promotes tree growth during succession in subtropical forest.

    Science.gov (United States)

    Barrufol, Martin; Schmid, Bernhard; Bruelheide, Helge; Chi, Xiulian; Hector, Andrew; Ma, Keping; Michalski, Stefan; Tang, Zhiyao; Niklaus, Pascal A

    2013-01-01

    Losses of plant species diversity can affect ecosystem functioning, with decreased primary productivity being the most frequently reported effect in experimental plant assemblages, including tree plantations. Less is known about the role of biodiversity in natural ecosystems, including forests, despite their importance for global biogeochemical cycling and climate. In general, experimental manipulations of tree diversity will take decades to yield final results. To date, biodiversity effects in natural forests therefore have only been reported from sample surveys or meta-analyses with plots not initially selected for diversity. We studied biomass and growth of subtropical forests stands in southeastern China. Taking advantage of variation in species recruitment during secondary succession, we adopted a comparative study design selecting forest plots to span a gradient in species richness. We repeatedly censored the stem diameter of two tree size cohorts, comprising 93 species belonging to 57 genera and 33 families. Tree size and growth were analyzed in dependence of species richness, the functional diversity of growth-related traits, and phylogenetic diversity, using both general linear and structural equation modeling. Successional age covaried with diversity, but differently so in the two size cohorts. Plot-level stem basal area and growth were positively related with species richness, while growth was negatively related to successional age. The productivity increase in species-rich, functionally and phylogenetically diverse plots was driven by both larger mean sizes and larger numbers of trees. The biodiversity effects we report exceed those from experimental studies, sample surveys and meta-analyses, suggesting that subtropical tree diversity is an important driver of forest productivity and re-growth after disturbance that supports the provision of ecological services by these ecosystems.

  13. Forest biomass carbon sinks in East Asia, with special reference to the relative contributions of forest expansion and forest growth.

    Science.gov (United States)

    Fang, Jingyun; Guo, Zhaodi; Hu, Huifeng; Kato, Tomomichi; Muraoka, Hiroyuki; Son, Yowhan

    2014-06-01

    Forests play an important role in regional and global carbon (C) cycles. With extensive afforestation and reforestation efforts over the last several decades, forests in East Asia have largely expanded, but the dynamics of their C stocks have not been fully assessed. We estimated biomass C stocks of the forests in all five East Asian countries (China, Japan, North Korea, South Korea, and Mongolia) between the 1970s and the 2000s, using the biomass expansion factor method and forest inventory data. Forest area and biomass C density in the whole region increased from 179.78 × 10(6) ha and 38.6 Mg C ha(-1) in the 1970s to 196.65 × 10(6) ha and 45.5 Mg C ha(-1) in the 2000s, respectively. The C stock increased from 6.9 Pg C to 8.9 Pg C, with an averaged sequestration rate of 66.9 Tg C yr(-1). Among the five countries, China and Japan were two major contributors to the total region's forest C sink, with respective contributions of 71.1% and 32.9%. In China, the areal expansion of forest land was a larger contributor to C sinks than increased biomass density for all forests (60.0% vs. 40.0%) and for planted forests (58.1% vs. 41.9%), while the latter contributed more than the former for natural forests (87.0% vs. 13.0%). In Japan, increased biomass density dominated the C sink for all (101.5%), planted (91.1%), and natural (123.8%) forests. Forests in South Korea also acted as a C sink, contributing 9.4% of the total region's sink because of increased forest growth (98.6%). Compared to these countries, the reduction in forest land in both North Korea and Mongolia caused a C loss at an average rate of 9.0 Tg C yr(-1), equal to 13.4% of the total region's C sink. Over the last four decades, the biomass C sequestration by East Asia's forests offset 5.8% of its contemporary fossil-fuel CO2 emissions. © 2014 John Wiley & Sons Ltd.

  14. Basal area growth impacts of dwarf misletoe on western hemlock in an old-growth forest

    Science.gov (United States)

    David C. Shaw; Huso Manuela; Howard Bruner

    2008-01-01

    We investigated the effect of western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosend.) G.N. Jones ssp. tsugense) on the 13-year basal area growth of large (>45.7 cm diameter at breast height) western hemlock (Tsuga heterophylla (Raf.) Sarg.) trees in an old-growth forest in southwestern Washington...

  15. Alfalfa Responses to Gypsum Application Measured Using Undisturbed Soil Columns

    Directory of Open Access Journals (Sweden)

    Rebecca Tirado-Corbalá

    2017-07-01

    Full Text Available Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1 untreated, (2 short-term (4-year annual applications of gypsum totaling 6720 kg ha−1, and (3 long-term (12-year annual applications of gypsum totaling 20,200 kg ha−1 on alfalfa (Medicago sativa L. growth and nutrient uptake, and gypsum movement through soil. The study was conducted in a greenhouse using undisturbed soil columns of two non-sodic soils (Celina silt loam and Brookston loam. Aboveground growth of alfalfa was not affected by gypsum treatments when compared with untreated (p > 0.05. Total root biomass (0–75 cm for both soils series was significantly increased by gypsum application (p = 0.04, however, increased root growth was restricted to 0–10 cm depth. Soil and plant analyses indicated no unfavorable environmental impact from of the 4-year and 12-year annual application of FGDG. We concluded that under sufficient water supply, by-product gypsum is a viable source of Ca and S for land application that might benefit alfalfa root growth, but has less effect on aboveground alfalfa biomass production. Undisturbed soil columns were a useful adaptation of the lysimeter method that allowed detailed measurements of alfalfa nutrient uptake, root biomass, and yield and nutrient movement in soil.

  16. Forest Typification to Characterize the Structure and Composition of Old-growth Evergreen Forests on Chiloe Island, North Patagonia (Chile

    Directory of Open Access Journals (Sweden)

    Jan R. Bannister

    2013-11-01

    Full Text Available The Evergreen forest type develops along the Valdivian and North-Patagonian phytogeographical regions of the south-central part of Chile (38° S–46° S. These evergreen forests have been scarcely studied south of 43° S, where there is still a large area made up of old-growth forests. Silvicultural proposals for the Evergreen forest type have been based on northern Evergreen forests, so that the characterization of the structure and composition of southern Evergreen forests, e.g., their typification, would aid in the development of appropriate silvicultural proposals for these forests. Based on the tree composition of 46 sampled plots in old-growth forests in an area of >1000 ha in southern Chiloé Island (43° S, we used multivariate analyses to define forest groups and to compare these forests with other evergreen forests throughout the Archipelago of North-Patagonia. We determined that evergreen forests of southern Chiloé correspond to the North-Patagonian temperate rainforests that are characterized by few tree species of different shade tolerance growing on fragile soils. We discuss the convenience of developing continuous cover forest management for these forests, rather than selective cuts or even-aged management that is proposed in the current legislation. This study is a contribution to forest classification for both ecologically- and forestry-oriented purposes.

  17. Pervasive growth reduction in Norway spruce forests following wind disturbance.

    Directory of Open Access Journals (Sweden)

    Rupert Seidl

    Full Text Available BACKGROUND: In recent decades the frequency and severity of natural disturbances by e.g., strong winds and insect outbreaks has increased considerably in many forest ecosystems around the world. Future climate change is expected to further intensify disturbance regimes, which makes addressing disturbances in ecosystem management a top priority. As a prerequisite a broader understanding of disturbance impacts and ecosystem responses is needed. With regard to the effects of strong winds--the most detrimental disturbance agent in Europe--monitoring and management has focused on structural damage, i.e., tree mortality from uprooting and stem breakage. Effects on the functioning of trees surviving the storm (e.g., their productivity and allocation have been rarely accounted for to date. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that growth reduction was significant and pervasive in a 6.79 million hectare forest landscape in southern Sweden following the storm Gudrun (January 2005. Wind-related growth reduction in Norway spruce (Picea abies (L. Karst. forests surviving the storm exceeded 10% in the worst hit regions, and was closely related to maximum gust wind speed (R(2 = 0.849 and structural wind damage (R(2 = 0.782. At the landscape scale, wind-related growth reduction amounted to 3.0 million m(3 in the three years following Gudrun. It thus exceeds secondary damage from bark beetles after Gudrun as well as the long-term average storm damage from uprooting and stem breakage in Sweden. CONCLUSIONS/SIGNIFICANCE: We conclude that the impact of strong winds on forest ecosystems is not limited to the immediately visible area of structural damage, and call for a broader consideration of disturbance effects on ecosystem structure and functioning in the context of forest management and climate change mitigation.

  18. Basal area growth for 15 tropical trees species in Puerto Rico. Forest

    Science.gov (United States)

    B. R. Parresol

    1995-01-01

    The tabonuco forest of Puerto Rico support a diverse population of tree species valued for timber, fuel, food, wildlife food and cover, and erosion control among other use. tree basal area growth data spanning 39 years are avaible on 15 species from eigth permanent plots in Luquillo Experimental Forest. The complexity of the rain forest challeges current forest...

  19. Benchmark carbon stocks from old-growth forests in northern New England, USA

    Science.gov (United States)

    Coeli M. Hoover; William B. Leak; Brian G. Keel

    2012-01-01

    Forests world-wide are recognized as important components of the global carbon cycle. Carbon sequestration has become a recognized forest management objective, but the full carbon storage potential of forests is not well understood. The premise of this study is that old-growth forests can be expected to provide a reasonable estimate of the upper limits of carbon...

  20. Spatial variability in forest growth—climate relationships in the Olympic Mountains, Washington.

    Science.gov (United States)

    Jill M. Nakawatase; David L. Peterson

    2006-01-01

    For many Pacific Northwest forests, little is known about the spatial and temporal variability in tree growth - climate relationships, yet it is this information that is needed to predict how forests will respond to future climatic change. We studied the effects of climatic variability on forest growth at 74 plots in the western and northeastern Olympic Mountains....

  1. The relations of growth and increment in thrace oak forests

    Directory of Open Access Journals (Sweden)

    Gafura Aylak Özdemir

    2016-01-01

    Full Text Available In this study, increment and growth relationships of oak forests of Thrace in different ages, densities and site indexes were examined. For this purpose, double-entry tree volume table, site quality table and the density - dependent yield table was created with the help of the data provided to 101 sample plots were taken. Density – dependent yield table was programmed using VBA macro feature of MS Excel 2010 program. Thus, yield table can be taken as output in computer environment according to the desired age, density and site index. Trends of stand volume and volume elements provided to density – dependent yield table for the oak forest of Thrace according to the age in different site conditions and densities was presented comparatively. Values obtained by density dependent yield table were compared with values of the yield table generated by Eraslan (1954 and Eraslan – Evcimen (1967 for the oak forests. The same comparison also was made with values of the yield table generated by Carus (1998 for beech forests with broad-leaved species.

  2. The effect of size and competition on tree growth rate in old-growth coniferous forests

    Science.gov (United States)

    Das, Adrian

    2012-01-01

    Tree growth and competition play central roles in forest dynamics. Yet models of competition often neglect important variation in species-specific responses. Furthermore, functions used to model changes in growth rate with size do not always allow for potential complexity. Using a large data set from old-growth forests in California, models were parameterized relating growth rate to tree size and competition for four common species. Several functions relating growth rate to size were tested. Competition models included parameters for tree size, competitor size, and competitor distance. Competitive strength was allowed to vary by species. The best ranked models (using Akaike’s information criterion) explained between 18% and 40% of the variance in growth rate, with each species showing a strong response to competition. Models indicated that relationships between competition and growth varied substantially among species. The results also suggested that the relationship between growth rate and tree size can be complex and that how we model it can affect not only our ability to detect that complexity but also whether we obtain misleading results. In this case, for three of four species, the best model captured an apparent and unexpected decline in potential growth rate for the smallest trees in the data set.

  3. Two decades of stability and change in old-growth forest at Mount Rainier National Park.

    Science.gov (United States)

    Steven A. Acker; Jerry F. Franklin; Sarah E. Greene; Ted B. Thomas; Robert Van Pelt; Kenneth J. Bible

    2006-01-01

    We examined how composition and structure of old-growth and mature forests at Mount Rainier National Park changed between the mid-1970s and mid-1990s. We assessed whether the patterns of forest dynamics observed in lower elevation old-growth forests in the Pacific Northwest held true for the higher-elevation forests of the Park. We used measurements of tree recruitment...

  4. Land-use dynamics influence estimates of carbon sequestration potential in tropical second-growth forest

    Science.gov (United States)

    Schwartz, Naomi B.; Uriarte, María; DeFries, Ruth; Gutierrez-Velez, Victor H.; Pinedo-Vasquez, Miguel A.

    2017-07-01

    Many countries have made major commitments to carbon sequestration through reforestation under the Paris Climate Agreement, and recent studies have illustrated the potential for large amounts of carbon sequestration in tropical second-growth forests. However, carbon gains in second-growth forests are threatened by non-permanence, i.e. release of carbon into the atmosphere from clearing or disturbance. The benefits of second-growth forests require long-term persistence on the landscape, but estimates of carbon potential rarely consider the spatio-temporal landscape dynamics of second-growth forests. In this study, we used remotely sensed imagery from a landscape in the Peruvian Amazon to examine patterns of second-growth forest regrowth and permanence over 28 years (1985-2013). By 2013, 44% of all forest cover in the study area was second growth and more than 50% of second-growth forest pixels were less than 5 years old. We modeled probabilities of forest regrowth and clearing as a function of landscape factors. The amount of neighboring forest and variables related to pixel position (i.e. distance to edge) were important for predicting both clearing and regrowth. Forest age was the strongest predictor of clearing probability and suggests a threshold response of clearing probability to age. Finally, we simulated future trajectories of carbon sequestration using the parameters from our models. We compared this with the amount of biomass that would accumulate under the assumption of second-growth permanence. Estimates differed by 900 000 tonnes, equivalent to over 80% of Peru’s commitment to carbon sequestration through ‘community reforestation’ under the Paris Agreement. Though the study area has more than 40 000 hectares of second-growth forest, only a small proportion is likely to accumulate significant carbon. Instead, cycles between forest and non-forest are common. Our results illustrate the importance of considering landscape dynamics when assessing

  5. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    Science.gov (United States)

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

  6. Area of old-growth forests in California, Oregon, and Washington.

    Science.gov (United States)

    Charles L. Bolsinger; Karen L. Waddell

    1993-01-01

    Area of old-growth forests in California, Oregon, and Washington has declined significantly in the second half of the 20th century. This report summarizes available information on old-growth forest area by ownership in California, Oregon, and Washington. Old-growth definitions used by the various owners and agencies are provided.

  7. Isotropic thaw subsidence in undisturbed permafrost landscapes

    Science.gov (United States)

    Shiklomanov, Nikolay I.; Streletskiy, Dmitry A.; Little, Jonathon D.; Nelson, Frederick E.

    2013-12-01

    in undisturbed terrain within some regions of the Arctic reveal limited correlation between increasing air temperature and the thickness of the seasonally thawed layer above ice-rich permafrost. Here we describe landscape-scale, thaw-induced subsidence lacking the topographic contrasts associated with thermokarst terrain. A high-resolution, 11 year record of temperature and vertical movement at the ground surface from contrasting physiographic regions of northern Alaska, obtained with differential global positioning systems technology, indicates that thaw of an ice-rich layer at the top of permafrost has produced decimeter-scale subsidence extending over the entire landscapes. Without specialized observation techniques the subsidence is not apparent to observers at the surface. This "isotropic thaw subsidence" explains the apparent stability of active layer thickness records from some landscapes of northern Alaska, despite warming near-surface air temperatures. Integrated over extensive regions, it may be responsible for thawing large volumes of carbon-rich substrate and could have negative impacts on infrastructure.

  8. Climate-driven speedup of alpine treeline forest growth in the Tianshan Mountains, Northwestern China.

    Science.gov (United States)

    Qi, Zhaohuan; Liu, Hongyan; Wu, Xiuchen; Hao, Qian

    2015-02-01

    Forest growth is sensitive to interannual climatic change in the alpine treeline ecotone (ATE). Whether the alpine treeline ecotone shares a similar pattern of forest growth with lower elevational closed forest belt (CFB) under changing climate remains unclear. Here, we reported an unprecedented acceleration of Picea schrenkiana forest growth since 1960s in the ATE of Tianshan Mountains, northwestern China by a stand-total sampling along six altitudinal transects with three plots in each transect: one from the ATE between the treeline and the forest line, and the other two from the CFB. All the sampled P. schrenkiana forest patches show a higher growth speed after 1960 and, comparatively, forest growth in the CFB has sped up much slower than that in the ATE. The speedup of forest growth at the ATE is mainly accounted for by climate factors, with increasing temperature suggested to be the primary driver. Stronger water deficit as well as more competition within the CFB might have restricted forest growth there more than that within the ATE, implying biotic factors were also significant for the accelerated forest growth in the ATE, which should be excluded from simulations and predictions of warming-induced treeline dynamics. © 2014 John Wiley & Sons Ltd.

  9. Multi-decade biomass dynamics in an old-growth hemlock-northern hardwood forest, Michigan, USA

    Directory of Open Access Journals (Sweden)

    Kerry D. Woods

    2014-09-01

    Full Text Available Trends in living aboveground biomass and inputs to the pool of coarse woody debris (CWD in an undisturbed, old-growth hemlock-northern hardwood forest in northern MI were estimated from multi-decade observations of permanent plots. Growth and demographic data from seven plot censuses over 47 years (1962–2009, combined with one-time measurement of CWD pools, help assess biomass/carbon status of this landscape. Are trends consistent with traditional notions of late-successional forests as equilibrial ecosystems? Specifically, do biomass pools and CWD inputs show consistent long-term trends and relationships, and can living and dead biomass pools and trends be related to forest composition and history? Aboveground living biomass densities, estimated using standard allometric relationships, range from 360–450 Mg/ha among sampled stands and types; these values are among the highest recorded for northeastern North American forests. Biomass densities showed significant decade-scale variation, but no consistent trends over the full study period (one stand, originating following an 1830 fire, showed an aggrading trend during the first 25 years of the study. Even though total above-ground biomass pools are neither increasing nor decreasing, they have been increasingly dominated, over the full study period, by very large (>70 cm dbh stems and by the most shade-tolerant species (Acer saccharum and Tsuga canadensis.CWD pools measured in 2007 averaged 151 m3/ha, with highest values in Acer-dominated stands. Snag densities averaged 27/ha, but varied nearly ten-fold with canopy composition (highest in Tsuga-dominated stands, lowest in Acer-dominated; snags constituted 10–50% of CWD biomass. Annualized CWD inputs from tree mortality over the full study period averaged 1.9–3.2 Mg/ha/yr, depending on stand and species composition. CWD input rates tended to increase over the course of the study. Input rates may be expected to increase over longer

  10. 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:...

  11. Modelling mixed forest growth : a review of models for forest management

    NARCIS (Netherlands)

    Porte, A.; Bartelink, H.H.

    2002-01-01

    Most forests today are multi-specific and heterogeneous forests (`mixed forests'). However, forest modelling has been focusing on mono-specific stands for a long time, only recently have models been developed for mixed forests. Previous reviews of mixed forest modelling were restricted to certain

  12. Dominance of the multicoloured Asian lady beetle Harmonia axyridis in an undisturbed wild meadow ecosystem

    Directory of Open Access Journals (Sweden)

    Élise Bélanger

    2011-12-01

    Full Text Available Fifteen years after its arrival in Quebec (Canada, the multicoloured Asian lady beetle Harmonia axyridis (Pallas 1773 (Coleoptera: Coccinellidae has become one of the dominant coccinellid species in agricultural, forested and urban areas. Several studies conducted in North American agricultural ecosystems show that the arrival of H. axyridis and other exotic coccinellid species was followed by decreases in the populations of native coccinellid species. In this study, the abundances of H. axyridis and other native and exotic species were determined in an undisturbed wild meadow located in a protected area. In 2009 and 2010, mainly Solidago canadensis L. (Asteraceae and Asclepias syriaca L. (Asclepiadaceae infested with aphids were surveyed. A total of 1522 individuals, belonging to seven different species, were recorded. In 2009, on all the plants monitored, H. axyridis was clearly the dominant species (69% of the coccinellid assemblage. In addition, this exotic species constituted 84% of the coccinellid assemblage, including Propylea quatuordecimpunctata (L. and Coccinella septempunctata (L. It is likely the dominance of the eurytopic Asian lady beetle in agricultural, forested, urban and undisturbed open ecosystems, poses a threat to native lady beetles. These results also provide evidence that undisturbed wild meadow ecosystems will not constitute a natural refuge from Harmonia axyridis for native species of lady beetles.

  13. Growth dynamics of fine roots in a coniferous fern forest site close to Forsmark in the central part of Sweden

    International Nuclear Information System (INIS)

    Persson, Hans; Stadenberg, Ingela

    2007-12-01

    The seasonal growth dynamics of live and dead roots for trees and the field layer species (g/m 2 , varying diameter fractions) and live/dead ratios were analysed at a fresh/moist coniferous fern forest site close to the nuclear power plant at Forsmark in the central eastern parts of Sweden. The changes in depth distribution of fine roots were observed at depth intervals of the top humus horizon down to 40 cm in the mineral soil profile. The bulk of living fine roots of trees ( 2 . The total quantity of fine roots (live + dead) amounted to 543, 434, 314 and 546 g/m 2 . Considerable quantities of fine roots (< 1 mm in diameter) were attributed to field-layer species (about 18% of the total biomass during the whole period of investigation). The turnover rate (the rate of construction of new roots) for tree fine roots < 1 mm in diameter amounted to at least the size of the average fine-root biomass. Our methods of estimating fine-root production and mortality, involved periodic measurements of live and dead dry weight of the fine roots from sequential core samples of the forest soil. The collected data give a proper and instant measure of the spatial and temporal distribution of fine roots in the undisturbed soil-profile. Data from other fine-root investigations suggest turnover rates in agreement with our present findings. Differences between root growth and turnover should be expected between trees of different age, tree species and different forest sites, but also between different years. Substantial variations in fine-root biomass, necromass and live/dead ratios are found in different forest sites. Correct methods for estimating the amount of live and dead fine-roots in the soil at regular time intervals are essential for any calculation of fine-root turnover. Definition of root vitality differs in literature, making it difficult to compare results from different root investigators. Our investigation clarifies the importance of using distinct morphological criteria

  14. Old-growth Montane Longleaf Pine Forest Age Structure: A Preliminary Assessment

    Science.gov (United States)

    J. Morgan Varner; John S. Kush; Ralph S. Meldahl

    1998-01-01

    Presettlement longleaf pine forests of the Southeast have been described as uneven-aged forests comprised of even-aged patches. Less than 4000 ha of old-growth longleaf forest remains. From these few sites remaining, a limited volume of age related literature has evolved, and these studies have been limited to the Lower Coastal Plain physiographic province. This study...

  15. Structure and Composition of Old-Growth and Unmanaged Second-Growth Riparian Forests at Redwood National Park, USA

    Directory of Open Access Journals (Sweden)

    Christopher R. Keyes

    2014-02-01

    Full Text Available Restoration of second-growth riparian stands has become an important issue for managers of redwood (Sequoia sempervirens [D. Don] Endl. forest reserves. Identifying differences between old-growth and second-growth forest vegetation is a necessary step in evaluating restoration needs and targets. The objective of this study was to characterize and contrast vegetation structure and composition in old-growth and unmanaged second-growth riparian forests in adjacent, geomorphologically similar watersheds at Redwood National Park. In the old-growth, redwood was the dominant overstory species in terms of stem density, basal area, and importance values. Second-growth was dominated by red alder (Alnus rubra Bong., Douglas-fir (Pseudotsuga menziesii [Mirbel] Franco, and redwood. Understory species were similar in both forests, with several key differences: Oxalis oregana Nutt. and Trillium ovatum Pursh had greater importance values in the old-growth, and Vaccinium parvifolium Sm., Dryopteris spp. and sedges Carex spp. had greater importance values in the second-growth. Notable differences in structure and composition suggest that restoration practices such as thinning could expedite the acquisition of old-growth characteristics in second-growth riparian forests.

  16. DRAINMOD-FOREST: Integrated Modeling of Hydrology, Soil Carbon and Nitrogen Dynamics, and Plant Growth for Drained Forests.

    Science.gov (United States)

    Tian, Shiying; Youssef, Mohamed A; Skaggs, R Wayne; Amatya, Devendra M; Chescheir, G M

    2012-01-01

    We present a hybrid and stand-level forest ecosystem model, DRAINMOD-FOREST, for simulating the hydrology, carbon (C) and nitrogen (N) dynamics, and tree growth for drained forest lands under common silvicultural practices. The model was developed by linking DRAINMOD, the hydrological model, and DRAINMOD-N II, the soil C and N dynamics model, to a forest growth model, which was adapted mainly from the 3-PG model. The forest growth model estimates net primary production, C allocation, and litterfall using physiology-based methods regulated by air temperature, water deficit, stand age, and soil N conditions. The performance of the newly developed DRAINMOD-FOREST model was evaluated using a long-term (21-yr) data set collected from an artificially drained loblolly pine ( L.) plantation in eastern North Carolina, USA. Results indicated that the DRAINMOD-FOREST accurately predicted annual, monthly, and daily drainage, as indicated by Nash-Sutcliffe coefficients of 0.93, 0.87, and 0.75, respectively. The model also predicted annual net primary productivity and dynamics of leaf area index reasonably well. Predicted temporal changes in the organic matter pool on the forest floor and in forest soil were reasonable compared to published literature. Both predicted annual and monthly nitrate export were in good agreement with field measurements, as indicated by Nash-Sutcliffe coefficients above 0.89 and 0.79 for annual and monthly predictions, respectively. This application of DRAINMOD-FOREST demonstrated its capability for predicting hydrology and C and N dynamics in drained forests under limited silvicultural practices. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  17. Spatial elements of mortality risk in old-growth forests

    Science.gov (United States)

    Das, Adrian; Battles, John; van Mantgem, Phillip J.; Stephenson, Nathan L.

    2008-01-01

    For many species of long-lived organisms, such as trees, survival appears to be the most critical vital rate affecting population persistence. However, methods commonly used to quantify tree death, such as relating tree mortality risk solely to diameter growth, almost certainly do not account for important spatial processes. Our goal in this study was to detect and, if present, to quantify the relevance of such processes. For this purpose, we examined purely spatial aspects of mortality for four species, Abies concolor, Abies magnifica, Calocedrus decurrens, and Pinus lambertiana, in an old-growth conifer forest in the Sierra Nevada of California, USA. The analysis was performed using data from nine fully mapped long-term monitoring plots.In three cases, the results unequivocally supported the inclusion of spatial information in models used to predict mortality. For Abies concolor, our results suggested that growth rate may not always adequately capture increased mortality risk due to competition. We also found evidence of a facilitative effect for this species, with mortality risk decreasing with proximity to conspecific neighbors. For Pinus lambertiana, mortality risk increased with density of conspecific neighbors, in keeping with a mechanism of increased pathogen or insect pressure (i.e., a Janzen-Connell type effect). Finally, we found that models estimating risk of being crushed were strongly improved by the inclusion of a simple index of spatial proximity.Not only did spatial indices improve models, those improvements were relevant for mortality prediction. For P. lambertiana, spatial factors were important for estimation of mortality risk regardless of growth rate. For A. concolor, although most of the population fell within spatial conditions in which mortality risk was well described by growth, trees that died occurred outside those conditions in a disproportionate fashion. Furthermore, as stands of A. concolor become increasingly dense, such spatial

  18. Multi-century Dynamics of an Ecotonal Mixed Old-growth Forest Under Global Change

    Science.gov (United States)

    Dorado Liñán, I.; Cañellas, I.; Valbuena-Carabaña, M.; Gil, L.; Gea-Izquierdo, G.

    2016-12-01

    Old-growth forests, particularly those located at the interface between different bioregions, are invaluable sources of long-term vegetation dynamics and historical stand response to perturbations. Although old-growth forest are scarce, the information gathered studying them may assist forest ecosystem restoration and management under forthcoming climate and land use changes. We analysed how complementary dynamics of a mixed old-growth forest composed by temperate (Fagus sylvatica, Quercus petraea) and submediterranean (Quercus pyrenaica) tree species were driven in response to short and long-term natural and anthropogenic disturbances during last two centuries. The old-growth forest is located at the interface between Mediterranean and temperate bioregions so the temperate species are growing at the dry and warm edges of their natural distribution area, whereas the submediterranean species Q. pyrenaica is at the core of the distribution range. Our results reflect historical shifts in forest dominance (as reflected by growth) induced by changes in climate and forest management between temperate and sub-Mediterranean species. This was particularly noticeable for F. sylvatica and Q. pyrenaica, the least and most drought-tolerant species, respectively. A reduction in growth of F. sylvatica unprecedented in the context of the last two hundred years was observed during the last decades concurrent with forest densification and marked changes in climate. Old-growth forests, particularly those located at the interface between different bioregions, are invaluable sources of long-term vegetation dynamics and historical stand response to perturbations. Although old-growth forest are scarce, the information gathered studying them may assist forest ecosystem restoration and management under forthcoming climate and land use changes. We analysed how complementary dynamics of a mixed old-growth forest composed by temperate (Fagus sylvatica, Quercus petraea) and submediterranean

  19. Information about old growth for selected forest type groups in the eastern United States.

    Science.gov (United States)

    Lucy E. Tyrrell; Gregory J. Nowacki; David S. Buckley; Elizabeth A. Nauertz; Jeffrey N. Niese; Jeanette L. Rollinger; John C. Zasada; John C. Zasada

    1998-01-01

    Compiles information about old-growth attributes for nine forest type groups that occur in the eastern United States. A range of values for each old-growth attribute for each forest type is summarized regionally from published and unpublished sources.

  20. Forest carbon dynamics associated with growth and disturbances in Oklahoma and Texas, 1992-2006

    Science.gov (United States)

    Daolan Zheng; Linda S. Heath; Mark J. Ducey; James E. Smith

    2013-01-01

    Quantifying forest carbon changes associated with growth and major disturbances is important for management of greenhouse gas emissions related to forests. Regional-level approaches with improved local growth data may refine estimates obtained using coarser resolution information. This study integrates remote-sensing-derived land cover change products, harvest data,...

  1. Remote Sensing Protocols for Parameterizing an Individual, Tree-Based, Forest Growth and Yield Model

    Science.gov (United States)

    2014-09-01

    Penelope Morgan. 2006. “Regression Modeling and Mapping of Coniferous Forest Basal Area and Tree Density from Discrete- Return LIDAR and... Basal Area Relationships of Open-Grown Southern Pines for Modeling Competition and Growth.” Canadian Journal of of Forest Research 22: 341–347... Forest Growth and Yield Model Co ns tr uc tio n En gi ne er in g R es ea rc h La bo ra to ry Scott A. Tweddale, Patrick J. Guertin, and

  2. Defining Old Growth for Fire-adapted Forests of the Western United States

    Directory of Open Access Journals (Sweden)

    Merrill R. Kaufmann

    2007-12-01

    Full Text Available There are varying definitions of old-growth forests because of differences in environment and differing fire influence across the Intermountain West. Two general types of forests reflect the role of fire: 1 forests shaped by natural changes in structure and species makeup - plant succession - that are driven by competitive differences among species and individual trees and by small-scale disturbances, and 2 forests where plant succession processes are disrupted by major biological disturbances (fire, insects, wind, or drought extending across larger areas. Some case examples of old-growth forests where fire was historically frequent are used. The examples sketch out the typical biophysical settings, fire regime, natural disturbance factors, spatial features of patches, and the processes and conditions that produce spatial changes of the landscape over time. These examples confirm the complexity of describing or defining old growth in frequent-fire forests. We define fire-adapted forests at three spatial scales, whereas the standard definition of old growth refers to a patch or stand condition. Our definition is based on ecological principles rather than on the cultural aspects of old growth. It focuses on central tendencies, given all the possible combinations of conditions and processes, that move forests toward old growth in the fire-adapted forests of the Intermountain West.

  3. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

    Science.gov (United States)

    Schwartz, Mark W; Dolanc, Christopher R; Gao, Hui; Strauss, Sharon Y; Schwartz, Ari C; Williams, John N; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th) century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

  4. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

    Directory of Open Access Journals (Sweden)

    Mark W Schwartz

    Full Text Available Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1 whether the forest appears in transition toward increased hardwood composition; 2 if conifers appear stressed by recent climate change relative to hardwoods; and 3 how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

  5. Influence of competition and age on tree growth in structurally complex old-growth forests in northern Minnesota, USA

    Science.gov (United States)

    Tuomas Aakala; Shawn Fraver; Anthony W. D' Amato; Brian J. Palik

    2013-01-01

    Factors influencing tree growth in structurally complex forests remain poorly understood. Here we assessed the influence of competition on Pinus resinosa (n = 224) and Pinus strobus (n = 90) growth in four old-growth stands in Minnesota, using mixed effects models. A subset of trees, with...

  6. Old-growth forest is what giant pandas really need.

    Science.gov (United States)

    Zhang, Zejun; Swaisgood, Ronald R; Zhang, Shanning; Nordstrom, Lisa A; Wang, Hongjia; Gu, Xiaodong; Hu, Jinchu; Wei, Fuwen

    2011-06-23

    Giant pandas (Ailuropoda melanoleuca) are an iconic conservation species, but despite significant research effort, do we understand what they really need? Estimating and mapping suitable habitat play a critical role in conservation planning and policy. But if assumptions about ecological needs are wrong, maps with misidentified suitable habitat will misguide conservation action. Here, we use an information-theoretic approach to analyse the largest, landscape-level dataset on panda habitat use to date, and challenge the prevailing wisdom about panda habitat needs. We show that pandas are associated with old-growth forest more than with any ecological variable other than bamboo. Other factors traditionally used in panda habitat models, such as topographic slope, are less important. We suggest that our findings are disparate from previous research in part because our research was conducted over a larger ecological scale than previous research conducted over more circumscribed areas within individual reserves. Thus, extrapolating from habitat studies on small scales to conservation planning on large scales may entail some risk. As the Chinese government is considering the renewal of its logging ban, it should take heed of the panda's dependency on old growth.

  7. Structure and development of old-growth, unmanaged second-growth, and extended rotation Pinus resinosa forests in Minnesota, USA

    Science.gov (United States)

    Silver, Emily J.; D'Amato, Anthony W.; Fraver, Shawn; Palik, Brian J.; Bradford, John B.

    2013-01-01

    The structure and developmental dynamics of old-growth forests often serve as important baselines for restoration prescriptions aimed at promoting more complex structural conditions in managed forest landscapes. Nonetheless, long-term information on natural patterns of development is rare for many commercially important and ecologically widespread forest types. Moreover, the effectiveness of approaches recommended for restoring old-growth structural conditions to managed forests, such as the application of extended rotation forestry, has been little studied. This study uses several long-term datasets from old growth, extended rotation, and unmanaged second growth Pinus resinosa (red pine) forests in northern Minnesota, USA, to quantify the range of variation in structural conditions for this forest type and to evaluate the effectiveness of extended rotation forestry at promoting the development of late-successional structural conditions. Long-term tree population data from permanent plots for one of the old-growth stands and the extended rotation stands (87 and 61 years, respectively) also allowed for an examination of the long-term structural dynamics of these systems. Old-growth forests were more structurally complex than unmanaged second-growth and extended rotation red pine stands, due in large part to the significantly higher volumes of coarse woody debris (70.7 vs. 11.5 and 4.7 m3/ha, respectively) and higher snag basal area (6.9 vs. 2.9 and 0.5 m2/ha, respectively). In addition, old-growth forests, although red pine-dominated, contained a greater abundance of other species, including Pinus strobus, Abies balsamea, and Picea glauca relative to the other stand types examined. These differences between stand types largely reflect historic gap-scale disturbances within the old-growth systems and their corresponding structural and compositional legacies. Nonetheless, extended rotation thinning treatments, by accelerating advancement to larger tree diameter

  8. An Old-Growth Definition for Western Hardwood Gallery Forests

    Science.gov (United States)

    Kelly Kindscher; Jenny Holah

    1998-01-01

    Western hardwood gallery forests are found across an extremely large, diverse geographical area that encompasses the Great Plains in the United States and Canada. Remnant forests of this type still exist in the "Prairie Peninsula," which historically projected an eastern finger into Ohio. The forests are restricted to floodplains of major rivers and are in...

  9. Arthropod Diversity and Functional Importance in Old-Growth Forests of North America

    Directory of Open Access Journals (Sweden)

    Timothy Schowalter

    2017-03-01

    Full Text Available Old-growth forests have become rare in North America but provide habitat for unique assemblages of species that often are rare in younger forests. Insects and related arthropods reach their highest diversity in old-growth forests because of their stable moderate temperature and relative humidity and the rich variety of resources represented by high plant species richness and structural complexity. Old-growth arthropod assemblages typically are distinct from those in younger, managed forests. Major subcommunities include the arboreal community that is composed of a rich assemblage of herbivores, fungivores, and their associated predators and parasitoids that function to regulate primary production and nutrient fluxes, the stem zone community that includes bark- and wood-boring species and their associated predators and parasitoids that initiate the decomposition of coarse woody debris, and the forest floor community composed of a variety of detritivores, fungivores, burrowers, and their associated predators and parasitoids that are instrumental in litter decomposition. Insect outbreaks are relatively rare in old-growth forests, where the diversity of resources and predators limit population growth. In turn, insects contribute to plant diversity and limit primary production of host plant species, thereby promoting development of old-growth forest characteristics. Arthropods also provide important functions in decomposition and nutrient cycling that may be lost in younger, managed forests with limited provision of coarse woody debris and accumulated litter. Protection of remnant old-growth forests within the forest matrix may be particularly valuable for maintaining the diversity of plant and arthropod predators that can minimize outbreaks, thereby contributing to resilience to changing environmental conditions.

  10. Climate Responses in Growth and Wood Anatomy of Imoprtant Forest Tree Species in Denmark

    DEFF Research Database (Denmark)

    Huang, Weiwei

    and decrease forest productivity. Q. robur is expected not only to tolerate the expected future climate including increasing water stress but also will presumably even prosper from the rising temperature. All other tested species are expected to have decreased growth and vitality, but to different degrees......The expected changes in global and regional climate, like drought episodes and increasing temperatures, are a challenge for forest management, as they will affect growth, mortalit y and species composition of future forests directly and mostly negatively. However, the long-term impacts of drought....... Based on the present results and supported by literature it is concluded that projected more severe and frequent drought episodes and higher autumn and summer temperatures will substantially affect the growth and xylem anatomy of most important temperate forest species and may change forest composition...

  11. Predicting the dynamics of a native Araucaria forest using a distance-independent individual tree-growth model

    OpenAIRE

    Enrique Orellana; Afonso Figueiredo Filho; Sylvio Péllico Netto; Jerome Klaas Vanclay

    2016-01-01

    Background: In recent decades, native Araucaria forests in Brazil have become fragmented due to the conversion of forest to agricultural lands and commercial tree plantations. Consequently, the forest dynamics in this forest type have been poorly investigated, as most fragments are poorly structured in terms of tree size and diversity. Methods: We developed a distance-independent individual tree-growth model to simulate the forest dynamics in a native Araucaria forest located pred...

  12. Assessing biomass accumulation in second growth forests of Puerto Rico using airborne lidar

    Science.gov (United States)

    Martinuzzi, S.; Cook, B.; Corp, L. A.; Morton, D. C.; Helmer, E.; Keller, M.

    2017-12-01

    Degraded and second growth tropical forests provide important ecosystem services, such as carbon sequestration and soil stabilization. Lidar data measure the three-dimensional structure of forest canopies and are commonly used to quantify aboveground biomass in temperate forest landscapes. However, the ability of lidar data to quantify second growth forest biomass in complex, tropical landscapes is less understood. Our goal was to evaluate the use of airborne lidar data to quantify aboveground biomass in a complex tropical landscape, the Caribbean island of Puerto Rico. Puerto Rico provides an ideal place for studying biomass accumulation because of the abundance of second growth forests in different stages of recovery, and the high ecological heterogeneity. Puerto Rico was almost entirely deforested for agriculture until the 1930s. Thereafter, agricultural abandonment resulted in a mosaic of second growth forests that have recovered naturally under different types of climate, land use, topography, and soil fertility. We integrated forest plot data from the US Forest Service, Forest Inventory and Analysis (FIA) Program with recent lidar data from NASA Goddard's Lidar, Hyperspectral, and Thermal (G-LiHT) airborne imager to quantify forest biomass across the island's landscape. The G-LiHT data consisted on targeted acquisitions over the FIA plots and other forested areas representing the environmental heterogeneity of the island. To fully assess the potential of the lidar data, we compared the ability of lidar-derived canopy metrics to quantify biomass alone, and in combination with intensity and topographic metrics. The results presented here are a key step for improving our understanding of the patterns and drivers of biomass accumulation in tropical forests.

  13. Gap Dynamics and Structure of Two Old-Growth Beech Forest Remnants in Slovenia

    Science.gov (United States)

    Rugani, Tihomir; Diaci, Jurij; Hladnik, David

    2013-01-01

    Context Due to a long history of intensive forest exploitation, few European beech (Fagus sylvatica L.) old-growth forests have been preserved in Europe. Material and Methods We studied two beech forest reserves in southern Slovenia. We examined the structural characteristics of the two forest reserves based on data from sample plots and complete inventory obtained from four previous forest management plans. To gain a better understanding of disturbance dynamics, we used aerial imagery to study the characteristics of canopy gaps over an 11-year period in the Kopa forest reserve and a 20-year period in the Gorjanci forest reserve. Results The results suggest that these forests are structurally heterogeneous over small spatial scales. Gap size analysis showed that gaps smaller than 500 m2 are the dominant driving force of stand development. The percentage of forest area in canopy gaps ranged from 3.2 to 4.5% in the Kopa forest reserve and from 9.1 to 10.6% in the Gorjanci forest reserve. These forests exhibit relatively high annual rates of coverage by newly established (0.15 and 0.25%) and closed (0.08 and 0.16%) canopy gaps. New gap formation is dependant on senescent trees located throughout the reserve. Conclusion We conclude that these stands are not even-sized, but rather unevenly structured. This is due to the fact that the disturbance regime is characterized by low intensity, small-scale disturbances. PMID:23308115

  14. Simulation of forest growth, applied to douglas fir stands in the Netherlands

    NARCIS (Netherlands)

    Mohren, G.M.J.

    1987-01-01

    Forest growth in relation to weather and soils is studied using a physiological simulation model. Growth potential depends on physiological characteristics of the plant species in combination with ambient weather conditions (mainly temperature and incoming radiation). For a given site, growth may be

  15. Housing growth, forests, and public lands in Northern Wisconsin form 1940 to 2000

    Science.gov (United States)

    Roger B. Hammer; Susan I. Stewart; Todd J. Hawbaker; Volker C. Radeloff

    2009-01-01

    Rural, forested areas throughout the United States are experiencing strong housing growth with potentially detrimental impacts on the environment. In this paper, we quantify housing growth in Northern Wisconsin over the last sixty years to determine if growth rates were higher near public lands, which may represent an important recreational amenity. We used data from...

  16. Toward detection of CO2 fertilization of tree growth and biomass accumulation in Amazon forests

    Science.gov (United States)

    Chambers, J. Q.; Negron Juarez, R. I.; Di Vittorio, A. V.; Marra, D.; Rifai, S. W.; Ribeiro, G.; Higuchi, N.

    2012-12-01

    Synthesis studies of old-growth tropical forest plot networks indicate a pantropical net carbon sink of more than 1 Pg C/yr. However a number of confounding factors limit our ability to attribute these changes to direct CO2 fertilization of tree growth and forest productivity. Of primary importance is determining if the plots adequately sample natural disturbance and recovery gradients, and the larger landscape successional mosaic. In addition, forest biomass dynamics which include tree growth, recruitment and mortality can interact in complex ways with changes in forest productivity and biomass accumulation. This study represents a novel approach to determine the sensitivity of different sampling strategies for detecting tropical forest CO2 fertilization while accounting for these confounding factors. Our approach, developed for Amazon forests in Brazil and Peru, combines extensive field plot data on biomass dynamics, remote sensing analyses to generate disturbance probability distribution functions, and individual-based simulation modeling for placing plot-level results into a landscape context. Results indicate that forest plots significantly larger than 10 ha are required to maximize the signal-to-noise ratio for detecting CO2 fertilization. We also present a field sampling strategy for quantifying site-to-site differences in forest biomass accumulation rates, which is useful for detecting regional differences in tropical forest sensitivity to rising atmospheric CO2 concentration. Overall, this approach is useful in developing field campaigns that explicitly account for landscape heterogeneity in testing key predictions of Earth system models.

  17. Spatial aspects of tree mortality strongly differ between young and old-growth forests.

    Science.gov (United States)

    Larson, Andrew J; Lutz, James A; Donato, Daniel C; Freund, James A; Swanson, Mark E; HilleRisLambers, Janneke; Sprugel, Douglas G; Franklin, Jerry F

    2015-11-01

    Rates and spatial patterns of tree mortality are predicted to change during forest structural development. In young forests, mortality should be primarily density dependent due to competition for light, leading to an increasingly spatially uniform pattern of surviving trees. In contrast, mortality in old-growth forests should be primarily caused by contagious and spatially autocorrelated agents (e.g., insects, wind), causing spatial aggregation of surviving trees to increase through time. We tested these predictions by contrasting a three-decade record of tree mortality from replicated mapped permanent plots located in young ( 300-year-old) Abies amabilis forests. Trees in young forests died at a rate of 4.42% per year, whereas trees in old-growth forests died at 0.60% per year. Tree mortality in young forests was significantly aggregated, strongly density dependent, and caused live tree patterns to become more uniform through time. Mortality in old-growth forests was spatially aggregated, but was density independent and did not change the spatial pattern of surviving trees. These results extend current theory by demonstrating that density-dependent competitive mortality leading to increasingly uniform tree spacing in young forests ultimately transitions late in succession to a more diverse tree mortality regime that maintains spatial heterogeneity through time.

  18. Some estimates of growth and mortality from the Malheur National Forest in eastern Oregon.

    Science.gov (United States)

    Donald R. Gedney; Floyd A. Johnson; Vernon E. Hicks

    1959-01-01

    During 1955-56 an inventory was made of forested land in the Middle Fork Working Circle of the Malheur National Forest to provide information necessary for calculation of the allowable cut and for other management purposes. The growth and mortality estimates in the following report were obtained from this inventory. Although the estimates apply directly to the Middle...

  19. Alternative definitions of growth and removals and implications for forest sustainability

    Science.gov (United States)

    Paul C. Van Deusen; Francis A. Roesch

    2008-01-01

    Alternative definitions for growth and removals from a forest being monitored over time are discussed. It is shown that the definitions that are used in practice may not be what one would expect and estimates can vary substantially under alternative definitions. This can result in conclusions about forest sustainability that may be misleading. Alternative definitions...

  20. Foliar and ecosystem respiration in an old-growth tropical rain forest

    Science.gov (United States)

    Molly A. Cavaleri; Steven F. Oberbauer; Michael G. Ryan

    2008-01-01

    Foliar respiration is a major component of ecosystem respiration, yet extrapolations are often uncertain in tropical forests because of indirect estimates of leaf area index (LAI).A portable tower was used to directly measure LAI and night-time foliar respiration from 52 vertical transects throughout an old-growth tropical rain forest in Costa Rica. In this study, we (...

  1. Global change induced biomass growth offsets carbon released via increased forest fire and respiration of the central Canadian boreal forest

    Science.gov (United States)

    Gonsamo, Alemu; Chen, Jing M.; Colombo, Stephen J.; Ter-Mikaelian, Michael T.; Chen, Jiaxin

    2017-05-01

    Northern boreal forests are sensitive to many effects of global change. This is of particular concern due to the proportionally greater climate change projected for the area in which these forests occur. One of the sensitive areas is the Far North of Ontario (FNO), consisting of one of the world's largest remaining tracts of unmanaged boreal forest, the world's third largest area of wetland, and the most southerly area of tundra. We studied past, present, and potential future carbon (C) balance of FNO forests using the Integrated Terrestrial Ecosystem Carbon Model and the Canadian Regional Climate Model with stand-replacing fire disturbance. The forced simulations of past (1901-2004) C balances indicated that vegetation C stock remained stable, while soil C stock gradually declined (-0.07 t C ha-1 yr-1, p climate growth-enhancing effects of global change will outweigh C loss through increased ecosystem respiration, disturbance, and changes in forest age class structure resulting in an increase in total FNO ecosystem C stock by mid-21st century. However, the projected simulations also indicated that the relative sizes of forest C stocks will change, with relatively less in the soil and more in vegetation, increasing fuel loads and making the entire ecosystem susceptible to forest fire and insect disturbances.

  2. Historical harvests reduce neighboring old-growth basal area across a forest landscape.

    Science.gov (United States)

    Bell, David M; Spies, Thomas A; Pabst, Robert

    2017-07-01

    While advances in remote sensing have made stand, landscape, and regional assessments of the direct impacts of disturbance on forests quite common, the edge influence of timber harvesting on the structure of neighboring unharvested forests has not been examined extensively. In this study, we examine the impact of historical timber harvests on basal area patterns of neighboring old-growth forests to assess the magnitude and scale of harvest edge influence in a forest landscape of western Oregon, USA. We used lidar data and forest plot measurements to construct 30-m resolution live tree basal area maps in lower and middle elevation mature and old-growth forests. We assessed how edge influence on total, upper canopy, and lower canopy basal area varied across this forest landscape as a function of harvest characteristics (i.e., harvest size and age) and topographic conditions in the unharvested area. Upper canopy, lower canopy, and total basal area increased with distance from harvest edge and elevation. Forests within 75 m of harvest edges (20% of unharvested forests) had 4% to 6% less live tree basal area compared with forest interiors. An interaction between distance from harvest edge and elevation indicated that elevation altered edge influence in this landscape. We observed a positive edge influence at low elevations (800 m). Surprisingly, we found no or weak effects of harvest age (13-60 yr) and harvest area (0.2-110 ha) on surrounding unharvested forest basal area, implying that edge influence was relatively insensitive to the scale of disturbance and multi-decadal recovery processes. Our study indicates that the edge influence of past clearcutting on the structure of neighboring uncut old-growth forests is widespread and persistent. These indirect and diffuse legacies of historical timber harvests complicate forest management decision-making in old-growth forest landscapes by broadening the traditional view of stand boundaries. Furthermore, the consequences

  3. Growth and demography of Pinaleno high elevation forests

    Science.gov (United States)

    Christopher O' Connor; Donald A. Falk; Ann M. Lynch; Craig P. Wilcox; Thomas W. Swetnam; Tyson L. Swetnam

    2010-01-01

    The project goal is to understand how multiple disturbance events including fire, insect outbreaks, and climate variability interact in space and time, and how they combine to influence forest species composition, spatial structure, and tree population dynamics in high elevation forests of the Pinaleno Mountains. Information from each of these components is needed in...

  4. Spatial relationship of biomass and species distribution in an old-growth Pseudotsuga Tsuga forest.

    Science.gov (United States)

    Jiquan Chen; Bo Song; Mark Rudnicki; Melinda Moeur; Ken Bible; Malcolm North; Dave C. Shaw; Jerry F. Franklin; Dave M. Braun

    2003-01-01

    Old-growth forests are known for their complex and variable structure and function. In a 12-ha plot (300 m x 400 m) of an old-growth Douglas-fir forest within the T.T. Munger Research Natural Area in southern Washington, we mapped and recorded live/dead condition, species, and diameter at breast height to address the following objectives: (1) to quantify the...

  5. An individual-based growth and competition model for coastal redwood forest restoration

    Science.gov (United States)

    van Mantgem, Phillip J.; Das, Adrian J.

    2014-01-01

    Thinning treatments to accelerate coastal redwood forest stand development are in wide application, but managers have yet to identify prescriptions that might best promote Sequoia sempervirens (Lamb. ex D. Don) Endl. (redwood) growth. The creation of successful thinning prescriptions would be aided by identifying the underlying mechanisms governing how individual tree growth responds to competitive environments in coastal redwood forests. We created a spatially explicit individual-based model of tree competition and growth parameterized using surveys of upland redwood forests at Redwood National Park, California. We modeled competition for overstory trees (stems ≥ 20 cm stem diameter at breast height, 1.37 m (dbh)) as growth reductions arising from sizes, distances, and species identity of competitor trees. Our model explained up to half of the variation in individual tree growth, suggesting that neighborhood crowding is an important determinant of growth in this forest type. We used our model to simulate the effects of novel thinning prescriptions (e.g., 40% stand basal area removal) for redwood forest restoration, concluding that these treatments could lead to substantial growth releases, particularly for S. sempervirens. The results of this study, along with continued improvements to our model, will help to determine spacing and species composition that best encourage growth.

  6. Spatial and temporal variability in forest growth in the Olympic Mountains, Washington : sensitivity to climatic variability

    Energy Technology Data Exchange (ETDEWEB)

    Holman, M.L. [Washington Univ., Seattle, WA (United States). College of Forest Resources; Peterson, D.L. [United States Dept. of Agriculture Forest Service, Seattle, WA (United States). Pacific Northwest Research Station

    2006-01-15

    Global climatic change may alter tree growth rates in some areas of the Pacific Northwest, which in turn could have a substantial effect on global carbon budgets. Annual basal area increment (BAI) was compared at different spatial scales among size classes and species at various locations in the western and northeastern Olympic Mountains. The aim of the study was to quantify variations in tree growth over the last 54 years and assess the sensitivity of Olympic forests to climate variability and change. Growth patterns for trees spanning a wide range of biophysical environments were examined at multiple spatial scales to determine the scale at which the trees had similar growth responses and the scale at which growth-limiting factors asserted their strongest influence. Mean interseries correlations were used to assess the degree of similarity among individual BAI time series per plot. Weak growth correlations at small spatial scales suggested that trees responded to local growth conditions. However, significant positive growth correlations between geographically adjacent forest types and watersheds indicated that there is a common overarching growth-limiting factor that affected tree growth over large areas. It was noted that the Sitka spruce forest type was the most sensitive to environmental change with the highest mean sensitivity, the highest potential for annual growth change, and the highest growth variability. In addition, this forest type was more likely to exhibit extreme positive growth responses. It was concluded that low elevation coniferous forests are relatively sensitive to changes in growth-limiting factors and may play an important role in storing carbon in a warmer climate. However, the study was limited by an inability to account for the effects of climate change on disturbances and biotic factors. 45 refs., 3 tabs., 5 figs.

  7. Biomass and water storage dynamics of epiphytes in old-growth and secondary montane cloud forest stands in Costa Rica

    NARCIS (Netherlands)

    Koehler, L.; Tobon, C.; Frumau, K.F.A.; Bruijnzeel, L.A.

    2007-01-01

    Epiphytic biomass, canopy humus and associated canopy water storage capacity are known to vary greatly between old-growth tropical montane cloud forests but for regenerating forests such data are virtually absent. The present study was conducted in an old-growth cloud forest and in a 30-year-old

  8. Diverse growth trends and climate responses across Eurasia's boreal forest

    Czech Academy of Sciences Publication Activity Database

    Hellmann, L.; Agafonov, L.; Ljungqvist, F. C.; Churakova (Sidorova), O.; Duethorn, E.; Esper, J.; Hulsmann, L.; Kirdyanov, A. V.; Moiseev, P.; Myglan, V. S.; Nikolaev, A. N.; Reinig, F.; Schweingruber, F. H.; Solomina, O.; Tegel, W.; Büntgen, Ulf

    2016-01-01

    Roč. 11, č. 7 (2016), č. článku 074021. ISSN 1748-9326 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : 20th-century summer warmth * tree-ring chronology * scots pine * 2 millennia * temperature variability * northern-hemisphere * central siberia * worlds forests * white spruce * carbon-cycle * boreal forest * climate variability * dendroecology * Eurasia * forest productivity * global warming * high northern latitudes Subject RIV: EH - Ecology, Behaviour Impact factor: 4.404, year: 2016

  9. Ground beetles as indicators of past management of old-growth forests

    Directory of Open Access Journals (Sweden)

    Mazzei A

    2017-06-01

    Full Text Available Old-growth forests are terrestrial ecosystems with the highest level of biodiversity and the main environments for the study of conservation and dynamics of the forest system. In Mediterranean Europe, two millennia of human exploitation deeply altered the structural complexity of the native forests. Some animal groups, including insects, may be used as a proxy of such changes. In this paper we explored the possible effects of forest management on the functional diversity (species traits of carabid beetle communities. Three old-growth forests of the Sila National Park were sampled by pitfall traps set up in pure beech, beech-silver fir and Calabrian black pine forests. In each forest, five managed vs. five unmanaged stands were considered. Managed sites were exploited until the sixties of the past century and then left unmanaged. More than 6000 carabid specimens belonging to 23 species were collected. The functional diversity in carabid groups is influenced by forest management especially in beech and beech-silver fir stands. Body size, specialized predators, endemic species and forest species were negatively affected by stand management. On the contrary, omnivorous ground beetles populations (or species with a high dispersal power (macropterous and large geographic distribution were positively influenced by stand management. In pine forests the old-growth community seems less sensitive to past management and more affected by soil evolution. Soil erosion and disturbance may reduce species diversity of ground beetles. Anyway, the composition of the carabid community shows that 50-60 years of forest restoration are enough for the reconstruction of a fairly diverse assemblage reflecting a “subclimax” situation.

  10. Forests synchronize their growth in contrasting Eurasian regions in response to climate warming.

    Science.gov (United States)

    Shestakova, Tatiana A; Gutiérrez, Emilia; Kirdyanov, Alexander V; Camarero, Jesús Julio; Génova, Mar; Knorre, Anastasia A; Linares, Juan Carlos; Resco de Dios, Víctor; Sánchez-Salguero, Raúl; Voltas, Jordi

    2016-01-19

    Forests play a key role in the carbon balance of terrestrial ecosystems. One of the main uncertainties in global change predictions lies in how the spatiotemporal dynamics of forest productivity will be affected by climate warming. Here we show an increasing influence of climate on the spatial variability of tree growth during the last 120 y, ultimately leading to unprecedented temporal coherence in ring-width records over wide geographical scales (spatial synchrony). Synchrony in growth patterns across cold-constrained (central Siberia) and drought-constrained (Spain) Eurasian conifer forests have peaked in the early 21st century at subcontinental scales (∼ 1,000 km). Such enhanced synchrony is similar to that observed in trees co-occurring within a stand. In boreal forests, the combined effects of recent warming and increasing intensity of climate extremes are enhancing synchrony through an earlier start of wood formation and a stronger impact of year-to-year fluctuations of growing-season temperatures on growth. In Mediterranean forests, the impact of warming on synchrony is related mainly to an advanced onset of growth and the strengthening of drought-induced growth limitations. Spatial patterns of enhanced synchrony represent early warning signals of climate change impacts on forest ecosystems at subcontinental scales.

  11. Carbon changes in conterminous US forests associated with growth and major disturbances: 1992-2001

    International Nuclear Information System (INIS)

    Zheng Daolan; Ducey, Mark J; Heath, Linda S; Smith, James E

    2011-01-01

    We estimated forest area and carbon changes in the conterminous United States using a remote sensing based land cover change map, forest fire data from the Monitoring Trends in Burn Severity program, and forest growth and harvest data from the USDA Forest Service, Forest Inventory and Analysis Program. Natural and human-associated disturbances reduced the forest ecosystems' carbon sink by 36% from 1992 to 2001, compared to that without disturbances in the 48 states. Among the three identified disturbances, forest-related land cover change contributed 33% of the total effect in reducing the forest carbon potential sink, while harvests and fires accounted for 63% and 4% of the total effect, respectively. The nation's forests sequestered 1.6 ± 0.1 Pg (10 15 petagram) carbon during the period, or 0.18 Pg C yr -1 , with substantial regional variation. The southern region of the United States was a small net carbon source whereas the greater Pacific Northwest region was a strong net sink. Results of the approach fit reasonably well at an aggregate level with other related estimates of the current forest US greenhouse gas inventory, suggesting that further research using this approach is warranted.

  12. Attaining the canopy in dry and moist tropical forests: strong differences in tree growth trajectories reflect variation in growing conditions.

    Science.gov (United States)

    Brienen, Roel J W; Zuidema, Pieter A; Martínez-Ramos, Miguel

    2010-06-01

    Availability of light and water differs between tropical moist and dry forests, with typically higher understorey light levels and lower water availability in the latter. Therefore, growth trajectories of juvenile trees--those that have not attained the canopy--are likely governed by temporal fluctuations in light availability in moist forests (suppressions and releases), and by spatial heterogeneity in water availability in dry forests. In this study, we compared juvenile growth trajectories of Cedrela odorata in a dry (Mexico) and a moist forest (Bolivia) using tree rings. We tested the following specific hypotheses: (1) moist forest juveniles show more and longer suppressions, and more and stronger releases; (2) moist forest juveniles exhibit wider variation in canopy accession pattern, i.e. the typical growth trajectory to the canopy; (3) growth variation among dry forest juveniles persists over longer time due to spatial heterogeneity in water availability. As expected, the proportion of suppressed juveniles was higher in moist than in dry forest (72 vs. 17%). Moist forest suppressions also lasted longer (9 vs. 5 years). The proportion of juveniles that experienced releases in moist forest (76%) was higher than in dry forest (41%), and releases in moist forests were much stronger. Trees in the moist forest also had a wider variation in canopy accession patterns compared to the dry forest. Our results also showed that growth variation among juvenile trees persisted over substantially longer periods of time in dry forest (>64 years) compared to moist forest (12 years), most probably because of larger persistent spatial variation in water availability. Our results suggest that periodic increases in light availability are more important for attaining the canopy in moist forests, and that spatial heterogeneity in water availability governs long-term tree growth in dry forests.

  13. Tree growth variation in the tropical forest: understanding effects of temperature, rainfall and CO2

    NARCIS (Netherlands)

    Schippers, P.; Sterck, F.J.; Vlam, M.; Zuidema, P.A.

    2015-01-01

    Tropical forest responses to climatic variability have important consequences for global carbon cycling, but are poorly understood. As empirical, correlative studies cannot disentangle the interactive effects of climatic variables on tree growth, we used a tree growth model (IBTREE) to unravel the

  14. Grow--a computer subroutine that projects the growth of trees in the Lake States' forests.

    Science.gov (United States)

    Gary J. Brand

    1981-01-01

    A computer subroutine, Grow, has been written in 1977 Standard FORTRAN to implement a distance-independent, individual tree growth model for Lake States' forests. Grow is a small and easy-to-use version of the growth model. All the user has to do is write a calling program to read initial conditions, call Grow, and summarize the results.

  15. Rapid warming accelerates tree growth decline in semi-arid forests of Inner Asia.

    Science.gov (United States)

    Liu, Hongyan; Park Williams, A; Allen, Craig D; Guo, Dali; Wu, Xiuchen; Anenkhonov, Oleg A; Liang, Eryuan; Sandanov, Denis V; Yin, Yi; Qi, Zhaohuan; Badmaeva, Natalya K

    2013-08-01

    Forests around the world are subject to risk of high rates of tree growth decline and increased tree mortality from combinations of climate warming and drought, notably in semi-arid settings. Here, we assess how climate warming has affected tree growth in one of the world's most extensive zones of semi-arid forests, in Inner Asia, a region where lack of data limits our understanding of how climate change may impact forests. We show that pervasive tree growth declines since 1994 in Inner Asia have been confined to semi-arid forests, where growing season water stress has been rising due to warming-induced increases in atmospheric moisture demand. A causal link between increasing drought and declining growth at semi-arid sites is corroborated by correlation analyses comparing annual climate data to records of tree-ring widths. These ring-width records tend to be substantially more sensitive to drought variability at semi-arid sites than at semi-humid sites. Fire occurrence and insect/pathogen attacks have increased in tandem with the most recent (2007-2009) documented episode of tree mortality. If warming in Inner Asia continues, further increases in forest stress and tree mortality could be expected, potentially driving the eventual regional loss of current semi-arid forests. © 2013 John Wiley & Sons Ltd.

  16. Structure and dynamics of an upland old- growth forest at Redwood National Park, California

    Science.gov (United States)

    van Mantgem, Philip J.; Stuart, John D.

    2011-01-01

    Many current redwood forest management targets are based on old-growth conditions, so it is critical that we understand the variability and range of conditions that constitute these forests. Here we present information on the structure and dynamics from six one-hectare forest monitoring plots in an upland old-growth forest at Redwood National Park, California. We surveyed all stems =20 cm DBH in 1995 and 2010, allowing us to estimate any systematic changes in these stands. Stem size distributions for all species and for redwood (Sequoia sempervirens (D. Don) Endl.) alone did not appreciably change over the 15 year observation interval. Recruitment and mortality rates were roughly balanced, as were basal area dynamics (gains from recruitment and growth versus losses from mortality). Similar patterns were found for Sequoia alone. The spatial structure of stems at the plots suggested a random distribution of trees, though the pattern for Sequoia alone was found to be significantly clumped at small scales (forests, including populations of Sequoia, have been generally stable over the past 15 years at this site, though it is possible that fire exclusion may be affecting recruitment of smaller Sequoia (forests that encourage uniform spatial arrangements do not appear to mimic current upland old-growth conditions.

  17. Comparing the plant diversity between artificial forest and nature growth forest in a giant panda habitat.

    Science.gov (United States)

    Kang, Dongwei; Wang, Xiaorong; Li, Shuang; Li, Junqing

    2017-06-15

    Artificial restoration is an important way to restore forests, but little is known about its effect on the habitat restoration of the giant panda. In the present study, we investigated the characteristics of artificial forest in the Wanglang Nature Reserve to determine whether through succession it has formed a suitable habitat for the giant panda. We compared artificial forest characteristics with those of natural habitat used by the giant panda. We found that the dominant tree species in artificial forest differed from those in the natural habitat. The artificial forest had lower plant species richness and diversity in the tree and shrub layers than did the latter, and its community structure was characterized by smaller tree and bamboo sizes, and fewer and lower bamboo clumps, but more trees and larger shrub sizes. The typical community collocation of artificial forest was a "Picea asperata + no-bamboo" model, which differs starkly from the giant panda's natural habitat. After several years of restoration, the artificial forest has failed to become a suitable habitat for the giant panda. Therefore, a simple way of planting individual trees cannot restore giant panda habitat; instead, habitat restoration should be based on the habitat requirements of the giant panda.

  18. Forests

    Science.gov (United States)

    Louis R. Iverson; Mark W. Schwartz

    1994-01-01

    Originally diminished by development, forests are coming back: forest biomass is accumulating. Forests are repositories for many threatened species. Even with increased standing timber, however, biodiversity is threatened by increased forest fragmentation and by exotic species.

  19. Influence of repeated prescribed fire on tree growth and mortality in Pinus resinosa forests, northern Minnesota

    Science.gov (United States)

    Bottero, Alessandra; D'Amato, Anthony W.; Palik, Brian J.; Kern, Christel C.; Bradford, John B.; Scherer, Sawyer S.

    2017-01-01

    Prescribed fire is widely used for ecological restoration and fuel reduction in fire-dependent ecosystems, most of which are also prone to drought. Despite the importance of drought in fire-adapted forests, little is known about cumulative effects of repeated prescribed burning on tree growth and related response to drought. Using dendrochronological data in red pine (Pinus resinosa Ait.)-dominated forests in northern Minnesota, USA, we examined growth responses before and after understory prescribed fires between 1960 and 1970, to assess whether repeated burning influences growth responses of overstory trees and vulnerability of overstory tree growth to drought. We found no difference in tree-level growth vulnerability to drought, expressed as growth resistance, resilience, and recovery, between areas receiving prescribed fire treatments and untreated forests. Annual mortality rates during the period of active burning were also low (less than 2%) in all treatments. These findings indicate that prescribed fire can be effectively integrated into management plans and climate change adaptation strategies for red pine forest ecosystems without significant short- or long-term negative consequences for growth or mortality rates of overstory trees.

  20. Low temperature growth of ultra-high mass density carbon nanotube forests on conductive supports

    International Nuclear Information System (INIS)

    Sugime, Hisashi; Esconjauregui, Santiago; Yang, Junwei; D'Arsié, Lorenzo; Robertson, John; Oliver, Rachel A.; Bhardwaj, Sunil; Cepek, Cinzia

    2013-01-01

    We grow ultra-high mass density carbon nanotube forests at 450 °C on Ti-coated Cu supports using Co-Mo co-catalyst. X-ray photoelectron spectroscopy shows Mo strongly interacts with Ti and Co, suppressing both aggregation and lifting off of Co particles and, thus, promoting the root growth mechanism. The forests average a height of 0.38 μm and a mass density of 1.6 g cm −3 . This mass density is the highest reported so far, even at higher temperatures or on insulators. The forests and Cu supports show ohmic conductivity (lowest resistance ∼22 kΩ), suggesting Co-Mo is useful for applications requiring forest growth on conductors

  1. Growth process and diameter structure of Pinus tabulaeformis forest ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... Using stem analysis method, the biomass, growing process and diameter structure of 21-year shady and sunny slope Pinus tabulaeformis forest were investigated in hilly loess-gully region. Results showed that there were distinct difference in the indexes, tree height, diameter at breast height (DBH).

  2. Growth process and diameter structure of Pinus tabulaeformis forest ...

    African Journals Online (AJOL)

    Using stem analysis method, the biomass, growing process and diameter structure of 21-year shady and sunny slope Pinus tabulaeformis forest were investigated in hilly loess-gully region. Results showed that there were distinct difference in the indexes, tree height, diameter at breast height (DBH) and timber volume ...

  3. Growth and yield as an indication of sustainable forest management ...

    African Journals Online (AJOL)

    Reported comparisons of forest productivity between successive rotations of Pinus radiata, P. patula, P. taeda and P. elliottii demonstrate that yield declines can occur when inappropriate forestry practices are applied to specific sites. Identification and understanding of these effects appear to have been initiated by data from ...

  4. Multidecadal analysis of forest growth and albedo in boreal Finland

    Czech Academy of Sciences Publication Activity Database

    Lukeš, Petr; Stenberg, P.; Mottus, M.; Manninen, T.; Rautiainen, M.

    2016-01-01

    Roč. 52, OCT (2016), s. 296-305 ISSN 0303-2434 R&D Projects: GA MŠk(CZ) LM2010007; GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : Albedo * fAPAR * LAI * NDVI * Time series * Seasonal trends * Forest structure Subject RIV: EH - Ecology, Behaviour Impact factor: 3.930, year: 2016

  5. A Novel Modelling Approach for Predicting Forest Growth and Yield under Climate Change.

    Science.gov (United States)

    Ashraf, M Irfan; Meng, Fan-Rui; Bourque, Charles P-A; MacLean, David A

    2015-01-01

    Global climate is changing due to increasing anthropogenic emissions of greenhouse gases. Forest managers need growth and yield models that can be used to predict future forest dynamics during the transition period of present-day forests under a changing climatic regime. In this study, we developed a forest growth and yield model that can be used to predict individual-tree growth under current and projected future climatic conditions. The model was constructed by integrating historical tree growth records with predictions from an ecological process-based model using neural networks. The new model predicts basal area (BA) and volume growth for individual trees in pure or mixed species forests. For model development, tree-growth data under current climatic conditions were obtained using over 3000 permanent sample plots from the Province of Nova Scotia, Canada. Data to reflect tree growth under a changing climatic regime were projected with JABOWA-3 (an ecological process-based model). Model validation with designated data produced model efficiencies of 0.82 and 0.89 in predicting individual-tree BA and volume growth. Model efficiency is a relative index of model performance, where 1 indicates an ideal fit, while values lower than zero means the predictions are no better than the average of the observations. Overall mean prediction error (BIAS) of basal area and volume growth predictions was nominal (i.e., for BA: -0.0177 cm(2) 5-year(-1) and volume: 0.0008 m(3) 5-year(-1)). Model variability described by root mean squared error (RMSE) in basal area prediction was 40.53 cm(2) 5-year(-1) and 0.0393 m(3) 5-year(-1) in volume prediction. The new modelling approach has potential to reduce uncertainties in growth and yield predictions under different climate change scenarios. This novel approach provides an avenue for forest managers to generate required information for the management of forests in transitional periods of climate change. Artificial intelligence technology

  6. A Novel Modelling Approach for Predicting Forest Growth and Yield under Climate Change.

    Directory of Open Access Journals (Sweden)

    M Irfan Ashraf

    Full Text Available Global climate is changing due to increasing anthropogenic emissions of greenhouse gases. Forest managers need growth and yield models that can be used to predict future forest dynamics during the transition period of present-day forests under a changing climatic regime. In this study, we developed a forest growth and yield model that can be used to predict individual-tree growth under current and projected future climatic conditions. The model was constructed by integrating historical tree growth records with predictions from an ecological process-based model using neural networks. The new model predicts basal area (BA and volume growth for individual trees in pure or mixed species forests. For model development, tree-growth data under current climatic conditions were obtained using over 3000 permanent sample plots from the Province of Nova Scotia, Canada. Data to reflect tree growth under a changing climatic regime were projected with JABOWA-3 (an ecological process-based model. Model validation with designated data produced model efficiencies of 0.82 and 0.89 in predicting individual-tree BA and volume growth. Model efficiency is a relative index of model performance, where 1 indicates an ideal fit, while values lower than zero means the predictions are no better than the average of the observations. Overall mean prediction error (BIAS of basal area and volume growth predictions was nominal (i.e., for BA: -0.0177 cm(2 5-year(-1 and volume: 0.0008 m(3 5-year(-1. Model variability described by root mean squared error (RMSE in basal area prediction was 40.53 cm(2 5-year(-1 and 0.0393 m(3 5-year(-1 in volume prediction. The new modelling approach has potential to reduce uncertainties in growth and yield predictions under different climate change scenarios. This novel approach provides an avenue for forest managers to generate required information for the management of forests in transitional periods of climate change. Artificial intelligence

  7. Tree growth and competition in an old-growth Picea abies forest of boreal Sweden: influence of tree spatial patterning

    Science.gov (United States)

    Fraver, Shawn; D'Amato, Anthony W.; Bradford, John B.; Jonsson, Bengt Gunnar; Jönsson, Mari; Esseen, Per-Anders

    2013-01-01

    Question: What factors best characterize tree competitive environments in this structurally diverse old-growth forest, and do these factors vary spatially within and among stands? Location: Old-growth Picea abies forest of boreal Sweden. Methods: Using long-term, mapped permanent plot data augmented with dendrochronological analyses, we evaluated the effect of neighbourhood competition on focal tree growth by means of standard competition indices, each modified to include various metrics of trees size, neighbour mortality weighting (for neighbours that died during the inventory period), and within-neighbourhood tree clustering. Candidate models were evaluated using mixed-model linear regression analyses, with mean basal area increment as the response variable. We then analysed stand-level spatial patterns of competition indices and growth rates (via kriging) to determine if the relationship between these patterns could further elucidate factors influencing tree growth. Results: Inter-tree competition clearly affected growth rates, with crown volume being the size metric most strongly influencing the neighbourhood competitive environment. Including neighbour tree mortality weightings in models only slightly improved descriptions of competitive interactions. Although the within-neighbourhood clustering index did not improve model predictions, competition intensity was influenced by the underlying stand-level tree spatial arrangement: stand-level clustering locally intensified competition and reduced tree growth, whereas in the absence of such clustering, inter-tree competition played a lesser role in constraining tree growth. Conclusions: Our findings demonstrate that competition continues to influence forest processes and structures in an old-growth system that has not experienced major disturbances for at least two centuries. The finding that the underlying tree spatial pattern influenced the competitive environment suggests caution in interpreting traditional tree

  8. Seedling growth in greenhouse conditions of the forest species Dialium guianense (Aubl.) Sandwith

    OpenAIRE

    Georgina Vargas Simon; Reinaldo Pire; Martha Olivia Lazaro Dzul

    2018-01-01

    Dialium guianense is used for its wood and fruit production, and is a tropical tree species native to evergreen forests. Given the threat these forests face, the purpose of this work was to evaluate the initial growth of the plant under greenhouse conditions, for aiming in the development of propagation programs. Seedlings of the species were transplanted to nursery bags under a completely randomized design and grown for 10 months with an initial population of 200 plants. At the end of the ex...

  9. Our New Cathedrals: Spirituality and Old-Growth Forests in Western Australia

    Directory of Open Access Journals (Sweden)

    David Worth

    2006-02-01

    Full Text Available Over the past 30 years in Western Australia (WA, there has been heated debate about the future use of the remaining karri and jarrah forests in the south-west of the State. This debate revolves around policy proposals from two social movements: one wants to preserve as much of the remaining old-growth forests as possible, and an opposing movement supports a continued

  10. Distribution of biomass in an Indiana old-growth forest from 1926 to 1992

    Science.gov (United States)

    Martin A. Spetich; George R. Parker

    1998-01-01

    We examined the structural and spatial distribution of woody biomass in relationship to disturbance in an Indiana old-growth deciduous forest over a 66-year period. Analysis was done on the core 7.92 ha of a 20.6 ha forest in which every tree 10 cm dbh and over has been tagged and mapped since 1926. Five years are compared - 1926, 1976, 1981, 1986 and 1992....

  11. Plot size recommendations for biomass estimation in a midwestern old-growth forest

    Science.gov (United States)

    Martin A. Spetich; George R Parker

    1998-01-01

    The authors examine the relationship between disturbance regime and plot size for woody biomass estimation in a midwestern old-growth deciduous forest from 1926 to 1992. Analysis was done on the core 19.6 ac of a 50.1 ac forest in which every tree 4 in. d.b.h. and greater has been tagged and mapped since 1926. Five windows of time are compared—1926, 1976, 1981, 1986...

  12. Tree species and soil nutrient profiles in old-growth forests of the Oregon Coast Range

    Science.gov (United States)

    Cross, Alison; Perakis, Steven S.

    2011-01-01

    Old-growth forests of the Pacific Northwest provide a unique opportunity to examine tree species – soil relationships in ecosystems that have developed without significant human disturbance. We characterized foliage, forest floor, and mineral soil nutrients associated with four canopy tree species (Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco), western hemlock (Tsuga heterophylla (Raf.) Sarg.), western redcedar (Thuja plicata Donn ex D. Don), and bigleaf maple (Acer macrophyllum Pursh)) in eight old-growth forests of the Oregon Coast Range. The greatest forest floor accumulations of C, N, P, Ca, Mg, and K occurred under Douglas-fir, primarily due to greater forest floor mass. In mineral soil, western hemlock exhibited significantly lower Ca concentration and sum of cations (Ca + Mg + K) than bigleaf maple, with intermediate values for Douglas-fir and western redcedar. Bigleaf maple explained most species-based differences in foliar nutrients, displaying high concentrations of N, P, Ca, Mg, and K. Foliar P and N:P variations largely reflected soil P variation across sites. The four tree species that we examined exhibited a number of individualistic effects on soil nutrient levels that contribute to biogeochemical heterogeneity in these ecosystems. Where fire suppression and long-term succession favor dominance by highly shade-tolerant western hemlock, our results suggest a potential for declines in both soil Ca availability and soil biogeochemical heterogeneity in old-growth forests.

  13. Undisturbed trapping boundary for energetic electrons at low altitudes

    International Nuclear Information System (INIS)

    Rossberg, L.

    1978-01-01

    Dawn-dusk traversals of the auroral zone by the German polar orbiting satellite Azur are used to reexamine the previously reported dawn-dusk asymmetry of the boundary position of the 40-keV electrons. This asymmetry, i.e., higher latitudes of the boundary positions in the dawn sector than in the dusk sector, disappears during prolonged periods of low electrojet activity. Symmetric boundary positions, i.e., significantly lower than average boundary positions in the dawn sector, are found whenever the electron flux decreases smoothly to the cosmic ray background over the polar cap and when there is no enhanced precipitation. Similar, undisturbed flux profiles observed by Ogo 6 at E>30keV are used to extend the study to all local times. The resulting average boundary contour has an almost circular shape, centered at 2 0 away from the magnetic pole on the midnight meridian and is compared with the average position of quiet auroral arcs and also with the average pattern of field-aligned currents for AL<100nT. The average boundary contour of undisturbed 30- and 40-keV electron flux profiles is interpreted as the high-latitude limit of stable trapping in the undisturbed magnetosphere

  14. A model inter-comparison study of forest growth on two coastal and boreal forest landscapes in Canada

    Science.gov (United States)

    Bernier, P. Y.; Wang, Z.; Grant, R. F.; Arain, A.; Chen, B.; Chen, J.; Coops, N.; Govind, A.; Guindon, L.; Hember, R.; Kurz, W. A.; Peng, C.; Price, D. T.; Stinson, G.; Sun, J.; Trofymow, J. A.

    2009-05-01

    Projection of carbon stocks in Canada is presently accomplished using CBM-CFS3, an inventory-based model. We have performed a comparison exercise among 6 process-based models of forest growth (Can-IBIS, INTEC, ECOSYS, 3PG, TRIPLEX, CN-CLASS) and CBM-CFS3 as part of an effort to better capture inter-annual climate variability in the carbon accounting of Canada's forests. Comparisons were made on multi-decadal simulations for a Pacific Coastal Douglas-fir forest (2500ha, Oyster River, British Columbia) and a Boreal Black Spruce forest (3825ha, Chibougamau, Quebec). Models were initiated using reconstructions of forest composition and biomass from 1920 (Oyster River, OR) and 1928 (Chibougamau, CH), followed by transition to current forest composition as derived from recent forest inventories (OR 1999, CH 1998). Forest management events and natural disturbances over the simulation period were provided as maps and disturbance impacts on a number of carbon pools were simulated using the same transfer coefficients parameters as CBM-CFS3. Simulations were conducted from 1920 to 2006 for OR, and from 1928 to 1998 for CH. For CH, final above-ground tree biomass in 1998 was also extracted from the independent forest inventory. The coastal OR area initially contained about four times more ecosystem C than the boreal CH area. CBM- CFS3 simulations suggest a decline in ecosystem carbon by about 200 Mg C ha-1, dominated by a loss of biomass and woody debris C, over the 86-year period in OR as the entire area transitioned from coastal old- growth to second growth conditions. In CH, a smaller proportion of the area was affected by management and the CBM-CFS3 estimated a small net increase in total ecosystem C of about 11 Mg C ha-1 over 70 years, almost all attributed to increased biomass. Changes in tree biomass at CH were 10% less than estimates derived by difference between successive inventories. The source of this small simulation bias is attributable to the underlying growth

  15. Runoff and soil erosion for an undisturbed tropical woodland in the Brazilian Cerrado

    Science.gov (United States)

    Oliveira, Paulo Tarso S.; Nearing, Mark; Wendland, Edson

    2015-04-01

    The Brazilian Cerrado is a large and important economic and environmental region that is experiencing major loss of its natural landscapes due to pressures of food and energy production, which has caused large increases in soil erosion. However the magnitude of the soil erosion increases in this region is not well understood, in part because scientific studies of surface runoff and soil erosion are scarce or nonexistent in undisturbed Cerrado vegetation. In this study we measured natural rainfall-driven rates of runoff and soil erosion for an undisturbed tropical woodland classified as "cerrado sensu stricto denso" and bare soil to compute the Universal Soil Loss Equation (USLE) cover and management factor (C-factor) to help evaluate the likely effects of land use change on soil erosion rates. Replicated data on precipitation, runoff, and soil loss on plots (5 x 20 m) under bare soil and cerrado were collected for 55 erosive storms occurring in 2012 and 2013. The measured annual precipitation was 1247.4 mm and 1113.0 mm for 2012 and 2013, resulting in a rainfall erosivity index of 4337.1 MJ mm ha-1 h-1 and 3546.2 MJ mm ha-1 h-1, for each year respectively. The erosive rainfall represented 80concentrated in the wet season, which generally runs from October through March. In the plots on bare soil, the runoff coefficient for individual rainfall events (total runoff divided by total rainfall) ranged from 0.003 to 0.860 with an average value and standard deviation of 0.212 ± 0.187. Moreover, the runoff coefficient found for the bare soil plots (~20infiltration capacity. In forest areas the leaf litter and the more porous soil tend to promote the increase of infiltration and water storage, rather than rapid overland flow. Indeed, runoff coefficients ranged from 0.001 to 0.030 with an average of less than 1under undisturbed cerrado. The soil losses measured under bare soil and cerrado were 15.68 t ha-1yr-1 and 0.24 t ha-1 yr-1 in 2012, and 14.82 t ha-1 yr-1, 0.11 t ha-1

  16. Measurement of undisturbed di-nitrogen emissions from aquatic ecosystems

    Science.gov (United States)

    Qin, Shuping, Clough, Timothy, Lou, Jiafa; Hu, Chunsheng; Oenema, Oene; Wrage-Mönnig, Nicole; Zhang, Yuming

    2016-04-01

    Increased production of reactive nitrogen (Nr) from atmospheric di-nitrogen (N2) during the last century has greatly contributed to increased food production1-4. However, enriching the biosphere with Nr through N fertilizer production, combustion, and biological N2 fixation has also caused a series of negative effects on global ecosystems 5,6, especially aquatic ecosystems7. The main pathway converting Nr back into the atmospheric N2 pool is the last step of the denitrification process, i.e., the reduction of nitrous oxide (N2O) into N2 by micro-organisms7,8. Despite several attempts9,10, there is not yet an accurate, fast and direct method for measuring undisturbed N2 fluxes from denitrification in aquatic sediments at the field scale11-14. Such a method is essential to study the feedback of aquatic ecosystems to Nr inputs1,2,7. Here we show that the measurement of both N2O emission and its isotope signature can be used to infer the undisturbed N2 fluxes from aquatic ecosystems. The microbial reduction of N2O increases the natural abundance of 15N-N2O relative to 14N-N2O (δ15N-N2O). We observed linear relationships between δ15N-N2O and the logarithmic transformed N2O/(N2+N2O) emission ratios. Through independent measurements, we verified that the undisturbed N2 flux from aquatic ecosystems can be inferred from measurements of N2O emissions and the δ15N-N2O signature. Our method allows the determination of field-scale N2 fluxes from undisturbed aquatic ecosystems, and thereby allows model predictions of denitrification rates to be tested. The undisturbed N2 fluxes observed are almost one order of magnitude higher than those estimated by the traditional method, where perturbation of the system occurs, indicating that the ability of aquatic ecosystems to remove Nr may have been severely underestimated.

  17. Kickstarting forest growth : seismic lines given step in right direction

    International Nuclear Information System (INIS)

    Harrison, L.

    2010-01-01

    The recently formed Oil Sands Leadership Initiative (OSLI) has started a program, known as Faster Forests, to replace trees cut down during seismic exploration in the Athabasca oil sands region. The focus is on in-situ areas where steam-assisted gravity drainage development has taken place. To date, 300,000 seedlings have been planted. Over many decades, seismic lines were cut into the boreal forest to explore for oil and gas, and the remediation practices of the past, or the lack thereof, left the forest damaged. The OSLI's five founding companies, all major players in the oil and gas industry, are committed to landscaping and replanting their areas, regardless of whether they were actually responsible for the damage, in order to facilitate the reforestation of the Wood Buffalo region. In consultation with a forestry company, strains of seedlings that are more successful are being selected for planting. The formation of OSLI is part of a commitment to improving the oil sands industry's reputation by demonstrating and communicating environmental, social, and economic performance. 1 ref., 2 figs.

  18. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics.

    Science.gov (United States)

    Chazdon, Robin L; Broadbent, Eben N; Rozendaal, Danaë M A; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T Mitchell; Balvanera, Patricia; Becknell, Justin M; Boukili, Vanessa; Brancalion, Pedro H S; Craven, Dylan; Almeida-Cortez, Jarcilene S; Cabral, George A L; de Jong, Ben; Denslow, Julie S; Dent, Daisy H; DeWalt, Saara J; Dupuy, Juan M; Durán, Sandra M; Espírito-Santo, Mario M; Fandino, María C; César, Ricardo G; Hall, Jefferson S; Hernández-Stefanoni, José Luis; Jakovac, Catarina C; Junqueira, André B; Kennard, Deborah; Letcher, Susan G; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R F; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A; Piotto, Daniel; Powers, Jennifer S; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B; Steininger, Marc K; Swenson, Nathan G; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D M; Vester, Hans; Vieira, Ima Celia G; Bentos, Tony Vizcarra; Williamson, G Bruce; Poorter, Lourens

    2016-05-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km(2) of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services.

  19. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

    Science.gov (United States)

    Chazdon, Robin L.; Broadbent, Eben N.; Rozendaal, Danaë M. A.; Bongers, Frans; Zambrano, Angélica María Almeyda; Aide, T. Mitchell; Balvanera, Patricia; Becknell, Justin M.; Boukili, Vanessa; Brancalion, Pedro H. S.; Craven, Dylan; Almeida-Cortez, Jarcilene S.; Cabral, George A. L.; de Jong, Ben; Denslow, Julie S.; Dent, Daisy H.; DeWalt, Saara J.; Dupuy, Juan M.; Durán, Sandra M.; Espírito-Santo, Mario M.; Fandino, María C.; César, Ricardo G.; Hall, Jefferson S.; Hernández-Stefanoni, José Luis; Jakovac, Catarina C.; Junqueira, André B.; Kennard, Deborah; Letcher, Susan G.; Lohbeck, Madelon; Martínez-Ramos, Miguel; Massoca, Paulo; Meave, Jorge A.; Mesquita, Rita; Mora, Francisco; Muñoz, Rodrigo; Muscarella, Robert; Nunes, Yule R. F.; Ochoa-Gaona, Susana; Orihuela-Belmonte, Edith; Peña-Claros, Marielos; Pérez-García, Eduardo A.; Piotto, Daniel; Powers, Jennifer S.; Rodríguez-Velazquez, Jorge; Romero-Pérez, Isabel Eunice; Ruíz, Jorge; Saldarriaga, Juan G.; Sanchez-Azofeifa, Arturo; Schwartz, Naomi B.; Steininger, Marc K.; Swenson, Nathan G.; Uriarte, Maria; van Breugel, Michiel; van der Wal, Hans; Veloso, Maria D. M.; Vester, Hans; Vieira, Ima Celia G.; Bentos, Tony Vizcarra; Williamson, G. Bruce; Poorter, Lourens

    2016-01-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We estimate the age and spatial extent of lowland second-growth forests in the Latin American tropics and model their potential aboveground carbon accumulation over four decades. Our model shows that, in 2008, second-growth forests (1 to 60 years old) covered 2.4 million km2 of land (28.1% of the total study area). Over 40 years, these lands can potentially accumulate a total aboveground carbon stock of 8.48 Pg C (petagrams of carbon) in aboveground biomass via low-cost natural regeneration or assisted regeneration, corresponding to a total CO2 sequestration of 31.09 Pg CO2. This total is equivalent to carbon emissions from fossil fuel use and industrial processes in all of Latin America and the Caribbean from 1993 to 2014. Ten countries account for 95% of this carbon storage potential, led by Brazil, Colombia, Mexico, and Venezuela. We model future land-use scenarios to guide national carbon mitigation policies. Permitting natural regeneration on 40% of lowland pastures potentially stores an additional 2.0 Pg C over 40 years. Our study provides information and maps to guide national-level forest-based carbon mitigation plans on the basis of estimated rates of natural regeneration and pasture abandonment. Coupled with avoided deforestation and sustainable forest management, natural regeneration of second-growth forests provides a low-cost mechanism that yields a high carbon sequestration potential with multiple benefits for biodiversity and ecosystem services. PMID:27386528

  20. Tree growth variation in the tropical forest: understanding effects of temperature, rainfall and CO2.

    Science.gov (United States)

    Schippers, Peter; Sterck, Frank; Vlam, Mart; Zuidema, Pieter A

    2015-01-28

    Tropical forest responses to climatic variability have important consequences for global carbon cycling, but are poorly understood. As empirical, correlative studies cannot disentangle the interactive effects of climatic variables on tree growth, we used a tree growth model (IBTREE) to unravel the climate effects on different physiological pathways and in turn on stem growth variation. We parameterized the model for canopy trees of Toona ciliata (Meliaceae) from a Thai monsoon forest and compared predicted and measured variation from a tree-ring study over a 30-year period. We used historical climatic variation of minimum and maximum day temperature, precipitation and carbon dioxide (CO 2 ) in different combinations to estimate the contribution of each climate factor in explaining the inter-annual variation in stem growth. Running the model with only variation in maximum temperature and rainfall yielded stem growth patterns that explained almost 70% of the observed inter-annual variation in stem growth. Our results show that maximum temperature had a strong negative effect on the stem growth by increasing respiration, reducing stomatal conductance and thus mitigating a higher transpiration demand, and - to a lesser extent - by directly reducing photosynthesis. Although stem growth was rather weakly sensitive to rain, stem growth variation responded strongly and positively to rainfall variation owing to the strong inter-annual fluctuations in rainfall. Minimum temperature and atmospheric CO 2 concentration did not significantly contribute to explaining the inter-annual variation in stem growth. Our innovative approach - combining a simulation model with historical data on tree-ring growth and climate - allowed disentangling the effects of strongly correlated climate variables on growth through different physiological pathways. Similar studies on different species and in different forest types are needed to further improve our understanding of the sensitivity of

  1. Chronic water stress reduces tree growth and the carbon sink of deciduous hardwood forests.

    Science.gov (United States)

    Brzostek, Edward R; Dragoni, Danilo; Schmid, Hans Peter; Rahman, Abdullah F; Sims, Daniel; Wayson, Craig A; Johnson, Daniel J; Phillips, Richard P

    2014-08-01

    Predicted decreases in water availability across the temperate forest biome have the potential to offset gains in carbon (C) uptake from phenology trends, rising atmospheric CO2 , and nitrogen deposition. While it is well established that severe droughts reduce the C sink of forests by inducing tree mortality, the impacts of mild but chronic water stress on forest phenology and physiology are largely unknown. We quantified the C consequences of chronic water stress using a 13-year record of tree growth (n = 200 trees), soil moisture, and ecosystem C balance at the Morgan-Monroe State Forest (MMSF) in Indiana, and a regional 11-year record of tree growth (n > 300 000 trees) and water availability for the 20 most dominant deciduous broadleaf tree species across the eastern and midwestern USA. We show that despite ~26 more days of C assimilation by trees at the MMSF, increasing water stress decreased the number of days of wood production by ~42 days over the same period, reducing the annual accrual of C in woody biomass by 41%. Across the deciduous forest region, water stress induced similar declines in tree growth, particularly for water-demanding 'mesophytic' tree species. Given the current replacement of water-stress adapted 'xerophytic' tree species by mesophytic tree species, we estimate that chronic water stress has the potential to decrease the C sink of deciduous forests by up to 17% (0.04 Pg C yr(-1) ) in the coming decades. This reduction in the C sink due to mesophication and chronic water stress is equivalent to an additional 1-3 days of global C emissions from fossil fuel burning each year. Collectively, our results indicate that regional declines in water availability may offset the growth-enhancing effects of other global changes and reduce the extent to which forests ameliorate climate warming. © 2014 John Wiley & Sons Ltd.

  2. Germination and initial growth of tree seedlings on deforested and natural forest soil at Dulhazara, Bangladesh.

    Science.gov (United States)

    Hossain, M Mohitul

    2012-12-01

    The destruction of natural forest is increasing due to urbanization, industrialization, settlement and for the agricultural expansion over last few decades, and studies for their recovery need to be undertaken. With this aim, this comparative study was designed to see the effects of deforested soil on germination and growth performance of five different tree species. In the experiment, five species namely Gmelina arborea, Swietenia mahagoni, Dipterocarpus turbinatus, Acacia auriculiformis and Syzygium grande were germinated for six weeks on seedbeds and raised in pots (25cm diameter, 30cm height), that were filled with two soil and type of land use: deforested and adjacent natural forest of Dulhazara Safari Park. Growth performance of seedling was observed up to 15 months based on height, collar diameter and biomass production at the end. Our results showed that the germination rate was almost similar in both type of land uses. Height growth of D. turbinatus, G. arborea and S. mahagoni seedlings was almost similar and A. auriculi formis and S. grande lower in deforested soil compared to natural forest soil, while collar diameter ofA. auriculi formis, G. arborea, S. grande and S. mahagoni lower and D. turbinatus similar in deforested soil compared to natural forest soil. After uprooting at 19 months, S. mahagoni seedlings were showed significantly (pnatural forest soil. Oven dry biomass of D. turbinatus seedlings at 19 month age in deforested soil was 21.96g (n=5) and in natural forest soil 18.86g (n=5). However, differences in germination rate and growth performance for different tree species indicated that soil are not too much deteriorated through deforestation at Dulhazara and without any failure such deforested lands would be possible to bring under forest through plantation.

  3. Survival and growth of three endangered oak species in a Mexican montane cloud forest

    Directory of Open Access Journals (Sweden)

    Ofelia Andrea Valdés-Rodríguez

    2017-07-01

    Full Text Available Cloud forests are amongst the world’s most impacted and endangered forest types, with Mexican cloud forests amongst the most degraded. These species rich forests are characterized by a diversity of congeneric oak species which dominate the canopy of mature forests. An improved understanding of the establishment requirements of oak seedlings in cloud forests is needed for conservation and restoration purposes. The aim of this study was to assess the influence of light conditions during early establishment of three endangered Quercus species. Seedling growth and biomass allocation in Quercus insignis M. Martens & Galeotti, Q. sartorii Liebm. and Q. xalapensis Bonpl. was determined under two light levels: light gap (1338 µmol m-2 s-1 and closed canopy (118 µmol m-2 s-1 in a cloud forest in Veracruz, Mexico. Growth and development were evaluated over the first 13 months. Results suggest there was a significant effect of light conditions on growth rate and biomass allocation. Although survival rate was similar among both environments, the three species showed lower growth rates under the closed canopy during the first nine months, while elongation rate was higher during the last three months under this environment compared to the light gap. Across all species, fresh biomass and dry biomass of roots, stem and leaves were almost 50% higher in light gap than under closed canopy. Q. insignis produced more biomass in shoots and roots than Q. sartorii and Q. xalapensis, which may increase its establishment success in shaded conditions. Results suggest that these three oak species are suited to planting in small gaps, but also in shaded understory conditions, as high early survival (>90% may allow enrichment planting in advance of gap creation.

  4. A volume change index for forest growth and sustainability

    Science.gov (United States)

    Paul Van Deusen; Francis Roesch

    2009-01-01

    A volume change index is suggested that is derived from growth components that can be estimated from remeasured plots. The new index incorporates more information than the traditional growth over removals, ratio. The new index directly indicates whether the standing volume will be increasing or decreasing if current conditions persist, whereas the ratio of...

  5. Soil acidification by atmospheric pollution and forest growth

    Science.gov (United States)

    Bengt Jonsson

    1976-01-01

    In recent years concern has been expressed about the danger of harmful pollution deposits which affect areas at great distances from the emission sources. The investigation was so designed that a possible reaction in growth resulting from a supposed acidification could be observed as far as possible. A poorer growth development was observed in regions, which are...

  6. Changes in growth of pristine boreal North American forests from 1950 to 2005 driven by landscape demographics and species traits

    Directory of Open Access Journals (Sweden)

    M. P. Girardin

    2012-07-01

    Full Text Available In spite of the many factors that are occurring and known for positively affecting the growth of forests, some boreal forests across North America have recently felt the adverse impacts of environmental changes. Knowledge of causes for productivity declines in North American boreal forests remains limited, and this is owed to the large spatial and temporal scales involved, and the many plant processes affected. Here, the response of pristine eastern boreal North American (PEBNA forests to ongoing climatic changes is examined using in situ data, community ecology statistics, and species-specific model simulations of carbon exchanges forced by contemporary climatic data. To examine trends in forest growth, we used a recently acquired collection of tree-ring width data from 252 sample plots distributed in PEBNA forests dominated by black spruce (Picea mariana [Mill.] B.S.P. and jack pine (Pinus banksiana Lamb.. Results of linear trend analysis on the tree growth data highlight a dominating forest growth decline in overmature forests (age > 120 years from 1950 to 2005. In contrast, improving growth conditions are seen in jack pine and mature (70–120 years black spruce stands. Multivariate analysis of climate and growth relationships suggests that responses of PEBNA forests to climate are dependent on demographic and species traits via their mediation of temperature and water stress constraints. In support of this hypothesis, the simulation experiment suggests that in old-growth black spruce stands the benefit to growth brought on by a longer growing season may have been low in comparison with the increasing moisture stress and respiration losses caused by warmer summer temperatures. Predicted increases in wildfire frequency in PEBNA forests will likely enhance the positive response of landscape-level forest growth to climate change by shifting the forest distribution to younger age classes while also enhancing the jack pine component.

  7. Forest growth and timber quality: crown models and simulation methods for sustainable forest management

    Science.gov (United States)

    Dennis P. Dykstra; Robert A. Monserud

    2009-01-01

    The purpose of the international conference from which these proceedings are drawn was to explore relationships between forest management activities and timber quality. Sessions were organized to explore models and simulation methodologies that contribute to an understanding of tree development over time and the ways that management and harvesting activities can...

  8. Integrating forest growth and harvesting cost models to improve forest management planning

    Science.gov (United States)

    J.E. Baumgras; C.B. LeDoux

    1991-01-01

    Two methods of estimating harvesting revenue--reported stumpage prices - and delivered prices minus estimated harvesting and haul costs were compared by estimating entry cash flows and rotation net present value for three simulated even-aged forest management options that included 1 to 3 thinnings over a 90 year rotation. Revenue estimates derived from stumpage prices...

  9. Conserving and Restoring Old Growth in Frequent-fire Forests: Cycles of Disruption and Recovery

    Directory of Open Access Journals (Sweden)

    Dave Egan

    2007-12-01

    Full Text Available I provide a synthesis of the papers in the Special Issue, The Conservation and Restoration of Old Growth in Frequent-fire Forests of the American West. These papers - the product of an Old Growth Writing Workshop, held at Northern Arizona University in Flagstaff, Arizona on 18-19 April 2006 - represent the ideas of 25 workshop participants who argue for a new attitude toward managing old growth in the frequent-fire forests of the American West. Unlike the lush, old-growth rainforests of the Pacific Northwest, the dry, frequent-fire forests of the western United States evolved with surface fires that disturbed the system with such regularity that young trees were almost always killed. When saplings did survive, they grew beyond the harm of frequent surface fires and, ultimately, attained the characteristics that define old growth in these systems. This system worked well, producing old-growth trees in abundance, until the onset of Euro-American settlement in the mid- to late-19th century. The arrival of these settlers put in motion an interplay of unprecedented social, political, economic, and ecological forces (e.g., removal of Native Americans and their fire-based land management systems, overgrazing of the understory, aggressive logging, establishment of federal land management agencies, implementation of a federal fire suppression policy. These activities have culminated in 1 overly dense forested ecosystems that are now on the verge of collapse because of catastrophic fires (i.e., crown fire at the landscape level; the Rodeo-Chediski Fire and insect outbreaks, 2 the emergence of conservation-minded environmental legislation and policy, and 3 greater levels of interaction between citizens, federal agencies, and fire-prone landscapes. Recognizing the tenuous ecological situation of these forests, restoration ecologists, foresters, and others have developed ways to return historic ecological processes and lower tree densities to these forests

  10. Declining Radial Growth Response of Coastal Forests to Hurricanes and Nor'easters

    Science.gov (United States)

    Fernandes, Arnold; Rollinson, Christine R.; Kearney, William S.; Dietze, Michael C.; Fagherazzi, Sergio

    2018-03-01

    The Mid-Atlantic coastal forests in Virginia are stressed by episodic disturbance from hurricanes and nor'easters. Using annual tree ring data, we adopt a dendroclimatic and statistical modeling approach to understand the response and resilience of a coastal pine forest to extreme storm events, over the past few decades. Results indicate that radial growth of trees in the study area is influenced by age, regional climate trends, and individual tree effects but dominated periodically by growth disturbance due to storms. We evaluated seven local extreme storm events to understand the effect of nor'easters and hurricanes on radial growth. A general decline in radial growth was observed in the year of the extreme storm and 3 years following it, after which the radial growth started recovering. The decline in radial growth showed a statistically significant correlation with the magnitude of the extreme storm (storm surge height and wind speed). This study contributes to understanding declining tree growth response and resilience of coastal forests to past disturbances. Given the potential increase in hurricanes and storm surge severity in the region, this can help predict vegetation response patterns to similar disturbances in the future.

  11. The Role of Old-growth Forests in Frequent-fire Landscapes

    Directory of Open Access Journals (Sweden)

    Daniel Binkley

    2007-12-01

    Full Text Available Classic ecological concepts and forestry language regarding old growth are not well suited to frequent-fire landscapes. In frequent-fire, old-growth landscapes, there is a symbiotic relationship between the trees, the understory graminoids, and fire that results in a healthy ecosystem. Patches of old growth interspersed with younger growth and open, grassy areas provide a wide variety of habitats for animals, and have a higher level of biodiversity. Fire suppression is detrimental to these forests, and eventually destroys all old growth. The reintroduction of fire into degraded frequent-fire, old-growth forests, accompanied by appropriate thinning, can restore a balance to these ecosystems. Several areas require further research and study: 1 the ability of the understory to respond to restoration treatments, 2 the rate of ecosystem recovery following wildfires whose level of severity is beyond the historic or natural range of variation, 3 the effects of climate change, and 4 the role of the microbial community. In addition, it is important to recognize that much of our knowledge about these old-growth systems comes from a few frequent-fire forest types.

  12. Do soil fertilization and forest canopy foliage affect the growth and photosynthesis of Amazonian saplings?

    Directory of Open Access Journals (Sweden)

    Nilvanda dos Santos Magalhães

    2014-02-01

    Full Text Available Most Amazonian soils are highly weathered and poor in nutrients. Therefore, photosynthesis and plant growth should positively respond to the addition of mineral nutrients. Surprisingly, no study has been carried out in situ in the central Amazon to address this issue for juvenile trees. The objective of this study was to determine how photosynthetic rates and growth of tree saplings respond to the addition of mineral nutrients, to the variation in leaf area index of the forest canopy, and to changes in soil water content associated with rainfall seasonality. We assessed the effect of adding a slow-release fertilizer. We determined plant growth from 2010 to 2012 and gas exchange in the wet and dry season of 2012. Rainfall seasonality led to variations in soil water content, but it did not affect sapling growth or leaf gas exchange parameters. Although soil amendment increased phosphorus content by 60 %, neither plant growth nor the photosynthetic parameters were influenced by the addition of mineral nutrients. However, photosynthetic rates and growth of saplings decreased as the forest canopy became denser. Even when Amazonian soils are poor in nutrients, photosynthesis and sapling growth are more responsive to slight variations in light availability in the forest understory than to the availability of nutrients. Therefore, the response of saplings to future increases in atmospheric [CO2] will not be limited by the availability of mineral nutrients in the soil.

  13. The effect of growth parameters on the height and density of carbon nanotube forests

    Science.gov (United States)

    Call, Robert W.

    Carbon nanotube forests (CNTFs) are grown using an injection chemical vapor deposition method. Images of CNTFs are taken using a scanning electron microscope and are used to measure their height and density. Growth parameters are systematically varied to determine their effect on the height and density of CNTFs. Investigations of CNTF density as a function of distance from the growth substrate reveal that diffusion can be a limiting factor on CNTF growth. Our findings indicate that height and density are related and that each growth parameter has multi-dimensional effects.

  14. Impacts of urban growth on forest cover in Istanbul (1987-2007).

    Science.gov (United States)

    Karaburun, Ahmet; Demirci, Ali; Suen, I-Shian

    2010-07-01

    This article reports findings of a study that examined the impacts of urban growth on forest cover in Istanbul between 1987 and 2007. Four Landsat images from 1987, 1990, 2000, and 2007 were classified with maximum likelihood supervised classification method by using ERDAS IMAGINE 9.1. Forest and urban areas were given highest importance in the classification, while other land-use characteristics, like agriculture and bare soil, were grouped into a third class as others. The study revealed that rapid increase in population and accompanying unplanned urban growth in Istanbul resulted in significant changes in land use after 1987. Urban areas have expanded 87.9% from 1987 to 2007, while forest areas declined 5.4% in the same period. One of the most significant results of the study was that total forest areas in Istanbul have increased 0.3% between 2000 and 2007. This suggests that progress has been made in Istanbul not only in having sustainable urban growth, but also in preserving, restoring, and even expanding forest areas, especially after the year 2000.

  15. Climate indices strongly influence old-growth forest carbon exchange

    Science.gov (United States)

    Sonia Wharton; Matthias Falk

    2016-01-01

    We present a decade and a half (1998–2013) of carbon dioxide fluxes from an old-growth stand in the American Pacific Northwest to identify ecosystem-level responses to Pacific teleconnection patterns, including the El Niño/Southern Oscillation (ENSO). This study provides the longest, continuous record of old-growth eddy flux data to date from one of the longest running...

  16. Increased water deficit decreases Douglas fir growth throughout western US forests

    Science.gov (United States)

    Restaino, Christina M; Peterson, David L.; Littell, Jeremy

    2016-01-01

    Changes in tree growth rates can affect tree mortality and forest feedbacks to the global carbon cycle. As air temperature increases, evaporative demand also increases, increasing effective drought in forest ecosystems. Using a spatially comprehensive network of Douglas-fir (Pseudotsuga menziesii) chronologies from 122 locations that experience distinctly different climate in the western United States, we show that increased temperature decreases growth via vapor pressure deficit (VPD) across all latitudes. Under an ensemble of global circulation models, we project an increase in both the mean VPD associated with the lowest growth extremes and the probability of exceeding these VPD values. As temperature continues to increase in future decades, we can expect deficit-related stress to increase and consequently Douglas-fir growth to decrease throughout its US range.

  17. Protecting rare, old-growth, forest-associated species under the Survey and Manage program guidelines of the northwest forest plan.

    Science.gov (United States)

    Randy Molina; Bruce G. Marcot; Robin. Lesher

    2006-01-01

    The Survey and Manage Program of the Northwest Forest Plan (MFP) represents an unparalleled attempt to protect rare, little-known species associated with late-successional and old-growth forests on more than 7.7 million ha of federal lands. Approximately 400 species of amphibians, bryophytes, fungi, lichens, mollusks, vascular plants, arthropod functional groups, and...

  18. Aridification determines changes in forest growth in Pinus halepensis forests under semiarid Mediterranean climate conditions

    OpenAIRE

    Vicente-Serrano, Sergio M.; Lasanta, Teodoro; Gracia, Carlos

    2010-01-01

    Using a set of 16 Landsat TM and Landsat ETM+ images from 1984 to 2006, we tested whether climate trends in the last three decades differentially controlled the vegetal activity of eight Pinus halepensis forests located across a marked bioclimatic gradient. Our results show spatial differences in trends in the normalized difference vegetation index (NDVI) between 1984 and 2006, which were highly related to the spatial distribution of aridity. There was a strong correlation between the change ...

  19. Population growth and the decline of natural Southern yellow pine forests

    Science.gov (United States)

    David B. South; Edward R. Buckner

    2004-01-01

    Population growth has created social and economic pressures that affect the sustainability of naturally regenerated southern yellow pine forests. Major causes of this decline include (1) a shift in public attitudes regarding woods burning (from one favoring it to one that favors fire suppression) and (2) an increase in land values (especially near urban centers). The...

  20. Do remnant old-growth trees accelerate rates of succession in mature Douglas-fir forests?

    Science.gov (United States)

    William S. Keeton; Jerry F. Franklin

    2005-01-01

    Biological legacies left by natural disturbances provide ecological functions throughout forest stand development, but their influences on processes of ecological succession are not completely understood. We investigated the successional role of one type of biological legacy: remnant old-growth trees persisting in mature Pseudotsuga menziesii (...

  1. Development of second-growth northern hardwoods on Bartlett Experimental Forest - a 25-year record

    Science.gov (United States)

    William B. Leak

    1961-01-01

    Second-growth timber occupies more than one-third of the commercial northern hardwood forest land in New England. The origin of these stands - clearcutting, or land abandonment with or without fire - determined their present characteristics; they are essentially even-aged, with a high proportion of intolerant and intermediate species and many stems of sprout origin (...

  2. Generalization of Faustmann's Formula for Stochastic Forest Growth and Prices with Markov Decision Process Models

    Science.gov (United States)

    Joseph Buongiorno

    2001-01-01

    Faustmann's formula gives the land value, or the forest value of land with trees, under deterministic assumptions regarding future stand growth and prices, over an infinite horizon. Markov decision process (MDP) models generalize Faustmann's approach by recognizing that future stand states and prices are known only as probabilistic distributions. The...

  3. Leaf traits determine the growth-survival trade-off across rain forest tree species

    NARCIS (Netherlands)

    Sterck, F.J.; Poorter, L.; Schieving, F.

    2006-01-01

    A dominant hypothesis explaining tree species coexistence in tropical forest is that trade-offs in characters allow species to adapt to different light environments, but tests for this hypothesis are scarce. This study is the first that uses a theoretical plant growth model to link leaf trade-offs

  4. Application of linked regional scale growth, biogeography, and economic models for southeastern United States pine forests

    Science.gov (United States)

    Steven G. McNulty; Jennifer A. Moore; Louis Iverson; Anantha Prasad; Robert, et al. Abt

    2000-01-01

    The southern United States produces over 50% of commercial timber harvests in the US and the demand for southern timber are likely to increase in the future. Global change is altering the physical and chemical environmental which will play a major role in determining future forest stand growth, insect and disease outbreaks, regeneration success, and distribution of...

  5. Patterns of diametric growth in stem-analyzed laurel trees (Cordia alliodora) in a Panamanian forest

    Science.gov (United States)

    Bernard R Parresol; Margaret S. Devall

    2013-01-01

    Based on cross-dated increment cores, yearly diameters of trees were reconstructed for 21 laurels (Cordia alliodora) growing in a natural secondary forest on Gigante Peninsula, Panama. From this sample of dominant-codominant trees, ages were 14–35 years with an average of 25 years. Growth typically slowed at 7 years old, indicating effects of...

  6. Idaho forest growth response to post-thinning energy biomass removal and complementary soil amendments

    Science.gov (United States)

    Lauren A. Sherman; Deborah S. Page-Dumroese; Mark D. Coleman

    2018-01-01

    Utilization of woody biomass for biofuel can help meet the need for renewable energy production. However, there is a concern biomass removal will deplete soil nutrients, having short- and long-term effects on tree growth. This study aimed to develop short-term indicators to assess the impacts of the first three years after small-diameter woody biomass removal on forest...

  7. Tree dynamics in canopy gaps in old-growth forests of Nothofagus pumilio in Southern Chile

    NARCIS (Netherlands)

    Fajardo, Alex; Graaf, de N.R.

    2004-01-01

    The gap dynamics of two Nothofagus pumilio (lenga) stands have been investigated. We evaluated and compared tree diameter distributions, spatial patterns, tree fall and gap characteristics and regeneration responses in gaps in two old-growth forests of Nothofagus pumilio in Southern Chile

  8. Silvicultural treatments enhance growth rates of future crop trees in a tropical dry forest

    NARCIS (Netherlands)

    Villegas, Z.; Peña-Claros, M.; Mostacedo, B.; Alarcón, A.; Licona, J.C.; Leaño, C.; Pariona, W.; Choque, U.

    2009-01-01

    Silvicultural treatments are often needed in selectively logged tropical forest to enhance the growth rates of many commercial tree species and, consequently, for recovering a larger proportion of the initial volume harvested over the next cutting cycle. The available data in the literature suggest,

  9. Driving factors of forest growth: a reply to Ferry et al. .

    NARCIS (Netherlands)

    Toledo, M.; Poorter, L.; Peña-Claros, M.; Alarcón, A.; Balcázar, J.; Leaño, C.; Licona, J.C.; Llanque, O.; Vroomans, V.; Zuidema, P.A.; Bongers, F.

    2012-01-01

    1. In a recent paper, we analysed the effects of climate, soil and logging disturbance on tree and forest growth (Toledo et al. 2011a). We took advantage of one of the largest data sets in the Neotropics, consisting of 165 1-ha plots and over 62 000 trees distributed over an area of c. 160 000 km2,

  10. Forty-two years of change in an old-growth and second-growth beech-maple forest of north central Ohio

    Science.gov (United States)

    Natalie R. Pinheiro; P. Charles Goebel; David M. Hix

    2008-01-01

    Using data collected in 1964 and 2006, we examined changes in the composition and structure of a second-growth and old-growth beech-maple forest of Crall Woods, located in Ashland County of north central Ohio. Over the 42 years, the old-growth forest (estimated to be at least 250 years old) experienced a significant shift in species composition as American beech,...

  11. Long-term growth decline in Toona ciliata in a moist tropical forest in Bangladesh: Impact of global warming

    Science.gov (United States)

    Rahman, Mizanur; Islam, Rofiqul; Islam, Mahmuda

    2017-04-01

    Tropical forests are carbon rich ecosystems and small changes in tropical forest tree growth substantially influence the global carbon cycle. Forest monitoring studies report inconsistent growth changes in tropical forest trees over the past decades. Most of the studies highlighted changes in the forest level carbon gain, neglecting the species-specific growth changes which ultimately determine community-level responses. Tree-ring analysis can provide historical data on species-specific tree growth with annual resolution. Such studies are inadequate in Bangladesh, which is one of the most climate sensitive regions in the tropics. In this study, we investigated long-term growth rates of Toona ciliata in a moist tropical forest of Bangladesh by using tree-ring analysis. We sampled 50 trees of varying size, obtained increment cores from these trees and measured tree-ring width. Analyses of growth patterns revealed size-dependent growth increments. After correcting for the effect of tree size on tree growth (ontogenetic changes) by two different methods we found declining growth rates in T. ciliata from 1960 to 2013. Standardized ring-width index (RWI) was strongly negatively correlated with annual mean and maximum temperatures suggesting that rising temperature might cause the observed growth decline in T. ciliata. Assuming that global temperatures will rise at the current rate, the observed growth decline is assumed to continue. The analysis of stable carbon and oxygen isotopes may reveal more insight on the physiological response of this species to future climatic changes.

  12. Growth process and diameter structure of Pinus tabulaeformis forest ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-10-19

    Oct 19, 2009 ... The mean coverage of floor vegetation is about 0.4. The predominant vegetation principally includes Lespedeza dahuricus, Artemisia sacrorum, Heteropaspus altacicus and Poa sphondylodes. Tree growth process. Plot and trunk analysis of the sample trees were used to evaluate the tree growing process.

  13. Growth rates of important East African montane forest trees, with ...

    African Journals Online (AJOL)

    Olea europaea ssp. cuspidata, Olea capensis ssp. hochstetteri and Cassipourea malosana had nearly equal growth rates, however, considerably lower than those of Juniperus procera and Podocarpus latifolius. Hagenia abyssinica fell within the range of the fast growing species, illustrating the ability of this species to ...

  14. Long-term forest resilience to climate change indicated by mortality, regeneration, and growth in semiarid southern Siberia.

    Science.gov (United States)

    Xu, Chongyang; Liu, Hongyan; Anenkhonov, Oleg A; Korolyuk, Andrey Yu; Sandanov, Denis V; Balsanova, Larisa D; Naidanov, Bulat B; Wu, Xiuchen

    2017-06-01

    Several studies have documented that regional climate warming and the resulting increase in drought stress have triggered increased tree mortality in semiarid forests with unavoidable impacts on regional and global carbon sequestration. Although climate warming is projected to continue into the future, studies examining long-term resilience of semiarid forests against climate change are limited. In this study, long-term forest resilience was defined as the capacity of forest recruitment to compensate for losses from mortality. We observed an obvious change in long-term forest resilience along a local aridity gradient by reconstructing tree growth trend and disturbance history and investigating postdisturbance regeneration in semiarid forests in southern Siberia. In our study, with increased severity of local aridity, forests became vulnerable to drought stress, and regeneration first accelerated and then ceased. Radial growth of trees during 1900-2012 was also relatively stable on the moderately arid site. Furthermore, we found that smaller forest patches always have relatively weaker resilience under the same climatic conditions. Our results imply a relatively higher resilience in arid timberline forest patches than in continuous forests; however, further climate warming and increased drought could possibly cause the disappearance of small forest patches around the arid tree line. This study sheds light on climate change adaptation and provides insight into managing vulnerable semiarid forests. © 2016 John Wiley & Sons Ltd.

  15. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees.

    Science.gov (United States)

    Liu, Lijun; Filkov, Vladimir; Groover, Andrew

    2014-06-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary growth), but a comprehensive understanding of how these genes interact to influence woody growth is currently lacking. Modeling transcriptional networks has recently been made tractable by next-generation sequencing-based technologies that can comprehensively catalog gene expression and transcription factor-binding genome-wide, but has not yet been extensively applied to undomesticated tree species or woody growth. Here we discuss basic features of transcriptional networks, approaches for modeling biological networks, and examples of biological network models developed for forest trees to date. We discuss how transcriptional network research is being developed in the model forest tree genus, Populus, and how this research area can be further developed and applied. Transcriptional network models for forest tree secondary growth and wood formation could ultimately provide new predictive models to accelerate hypothesis-driven research and develop new breeding applications. © 2013 Scandinavian Plant Physiology Society.

  16. Belowground Competition Directs Spatial Patterns of Seedling Growth in Boreal Pine Forests in Fennoscandia

    Directory of Open Access Journals (Sweden)

    E. Petter Axelsson

    2014-09-01

    Full Text Available Aboveground competition is often argued to be the main process determining patterns of natural forest regeneration. However, the theory of multiple resource limitation suggests that seedling performance also depends on belowground competition and, thus, that their relative influence is of fundamental importance. Two approaches were used to address the relative importance of above- and below-ground competition on regeneration in a nutrient-poor pine (Pinus sylvestris boreal forest. Firstly, seedling establishment beneath trees stem-girdled 12 years ago show that a substantial proportion of the seedlings were established within two years after girdling, which corresponds to a time when nutrient uptake by tree roots was severely reduced without disrupting water transport to the tree canopy, which consequently was maintained. The establishment during these two years also corresponds to abundances high enough for normal stand replacement. Secondly, surveys of regeneration within forest gaps showed that surrounding forests depressed seedlings, so that satisfactory growth occurred only more than 5 m from forest edges and that higher solar radiation in south facing edges was not enough to mediate these effects. We conclude that disruption of belowground competitive interactions mediates regeneration and, thus, that belowground competition has a strong limiting influence on seedling establishment in these forests.

  17. Agricultural Abandonment, Suburban Growth, and Forest Expansion in Puerto Rico between 1991 and 2000

    Directory of Open Access Journals (Sweden)

    Isabel K. Parés-Ramos

    2008-12-01

    Full Text Available The response of local economies to the globalization process can have a large effect on population and land-use dynamics. In countries with a high population density and relatively high levels of education, the globalization process has resulted in a shift in the local economy from agriculture to manufacturing, technology, and service sectors. This shift in the economy has impacted land-use dynamics by decreasing agricultural lands, increasing urban growth, and in some cases, increasing forest cover. This process of economic and forest transition has been well documented in Puerto Rico for the period 1950 to 1990, but some authors predicted that poor planning and continued urban growth would eliminate the gains in forest cover. To investigate the impacts of recent economic changes, we evaluated demographic and land-use changes for 880 "barrios" (i.e., neighborhoods, the smallest administrative unit, in Puerto Rico using government census data from 1990 and 2000 and land-cover classifications from 1991 and 2000. During this period, the population increased by 284 127 people (8.2%. Most of the growth was in the suburban barrios, whereas urban barrios lost population. This shift was reflected by the construction of more than 100 000 housing units in suburban barrios. Although urban sprawl is perceived as the major land-cover change, urban cover only increased from 10% to 11% between 1990 and 2000, whereas the increase in forest cover was much greater (28% to 40%. Grasslands and shrublands were the major sources of new urban and forest areas in 2000. Although these results are encouraging in terms of increasing forest cover, most of the new development has been concentrated in the coastal plains, which are the location of most of the remaining agricultural areas, a few protected areas, and threatened ecosystems (e.g., mangroves.

  18. Windthrow and salvage logging in an old-growth hemlock-northern hardwoods forest

    Science.gov (United States)

    Lang, K.D.; Schulte, L.A.; Guntenspergen, G.R.

    2009-01-01

    Although the initial response to salvage (also known as, post-disturbance or sanitary) logging is known to vary among system components, little is known about longer term forest recovery. We examine forest overstory, understory, soil, and microtopographic response 25 years after a 1977 severe wind disturbance on the Flambeau River State Forest in Wisconsin, USA, a portion of which was salvage logged. Within this former old-growth hemlock-northern hardwoods forest, tree dominance has shifted from Eastern hemlock (Tsuga canadensis) to broad-leaf deciduous species (Ulmus americana, Acer saccharum, Tilia americana, Populus tremuloides, and Betula alleghaniensis) in both the salvaged and unsalvaged areas. While the biological legacies of pre-disturbance seedlings, saplings, and mature trees were initially more abundant in the unsalvaged area, regeneration through root suckers and stump sprouts was common in both areas. After 25 years, tree basal area, sapling density, shrub layer density, and seedling cover had converged between unsalvaged and salvaged areas. In contrast, understory herb communities differed between salvaged and unsalvaged forest, with salvaged forest containing significantly higher understory herb richness and cover, and greater dominance of species benefiting from disturbance, especially Solidago species. Soil bulk density, pH, organic carbon content, and organic nitrogen content were also significantly higher in the salvaged area. The structural legacy of tip-up microtopography remains more pronounced in the unsalvaged area, with significantly taller tip-up mounds and deeper pits. Mosses and some forest herbs, including Athyrium filix-femina and Hydrophyllum virginianum, showed strong positive responses to this tip-up microrelief, highlighting the importance of these structural legacies for understory biodiversity. In sum, although the pathways of recovery differed, this forest appeared to be as resilient to the compound disturbances of windthrow

  19. 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.

  20. Similar biodiversity of ectomycorrhizal fungi in set-aside plantations and ancient old-growth broadleaved forests.

    Science.gov (United States)

    Spake, Rebecca; van der Linde, Sietse; Newton, Adrian C; Suz, Laura M; Bidartondo, Martin I; Doncaster, C Patrick

    2016-02-01

    Setting aside overmature planted forests is currently seen as an option for preserving species associated with old-growth forests, such as those with dispersal limitation. Few data exist, however, on the utility of set-aside plantations for this purpose, or the value of this habitat type for biodiversity relative to old-growth semi-natural ecosystems. Here, we evaluate the contribution of forest type relative to habitat characteristics in determining species richness and composition in seven forest blocks, each containing an ancient old-growth stand (> 1000 yrs) paired with a set-aside even-aged planted stand (ca. 180 yrs). We investigated the functionally important yet relatively neglected ectomycorrhizal fungi (EMF), a group for which the importance of forest age has not been assessed in broadleaved forests. We found that forest type was not an important determinant of EMF species richness or composition, demonstrating that set-aside can be an effective option for conserving ancient EMF communities. Species richness of above-ground EMF fruiting bodies was principally related to the basal area of the stand (a correlate of canopy cover) and tree species diversity, whilst richness of below-ground ectomycorrhizae was driven only by tree diversity. Our results suggest that overmature planted forest stands, particularly those that are mixed-woods with high basal area, are an effective means to connect and expand ecological networks of ancient old-growth forests in historically deforested and fragmented landscapes for ectomycorrhizal fungi.

  1. Growth Model of Pine (Pinus merkusii Jungh. Et de Vriese Stand on Community Forest in Tana Toraja Regency

    Directory of Open Access Journals (Sweden)

    Melewanto Patabang

    2014-04-01

    Full Text Available Growth modeling and yield simulation of forest is a very important aspect in forest management including community forests. Stand growth model is an abstraction of the dynamic nature of a forest stand, including growth, ingrowths, mortality, and other changes in the structure and composition of the stand. In forest management, growth estimation plays an important role in supporting the sustainability of the benefits value of the community forests. The objectives of the research were to find out the stand growth model and the potential of community's pine forest. The study was conducted at the location of the community pine forests in District Mengkendek Tana Toraja Regency. Sample location, as representative of stand age classes that distribute on some villages in Mengkendek District, were selected by purposive sampling.The study results indicate that the most suitable model for upper trees mean height (H is Weibull Model, for growth diameter and growth volume is Logistic Model  . The stand mean height (h can be presented as a function of H and Relative Spacing Ratio (Sr on the basis of function log Sr = 0,197 – 0,653 log H, then the tree volume, can be estimated on the basis of function log V = -1,70 + 0,94logD + 1,50logh, and then the growth function of volume on the basis of function V = 1.008 / 1 + 251.322 exp(-0.373t. Further, the maximum value of stand Annual Increment was 18 m3ha-1year-1, attained at the age of 20 years.Keywords: community's pine forest, stand growth, tree volume, annual increment

  2. Modeling Forest Biomass and Growth: Coupling Long-Term Inventory and Lidar Data

    Science.gov (United States)

    Babcock, Chad; Finley, Andrew O.; Cook, Bruce D.; Weiskittel, Andrew; Woodall, Christopher W.

    2016-01-01

    Combining spatially-explicit long-term forest inventory and remotely sensed information from Light Detection and Ranging (LiDAR) datasets through statistical models can be a powerful tool for predicting and mapping above-ground biomass (AGB) at a range of geographic scales. We present and examine a novel modeling approach to improve prediction of AGB and estimate AGB growth using LiDAR data. The proposed model accommodates temporal misalignment between field measurements and remotely sensed data-a problem pervasive in such settings-by including multiple time-indexed measurements at plot locations to estimate AGB growth. We pursue a Bayesian modeling framework that allows for appropriately complex parameter associations and uncertainty propagation through to prediction. Specifically, we identify a space-varying coefficients model to predict and map AGB and its associated growth simultaneously. The proposed model is assessed using LiDAR data acquired from NASA Goddard's LiDAR, Hyper-spectral & Thermal imager and field inventory data from the Penobscot Experimental Forest in Bradley, Maine. The proposed model outperformed the time-invariant counterpart models in predictive performance as indicated by a substantial reduction in root mean squared error. The proposed model adequately accounts for temporal misalignment through the estimation of forest AGB growth and accommodates residual spatial dependence. Results from this analysis suggest that future AGB models informed using remotely sensed data, such as LiDAR, may be improved by adapting traditional modeling frameworks to account for temporal misalignment and spatial dependence using random effects.

  3. The value of volume and growth measurements in timber sales management of the National Forests

    Science.gov (United States)

    Lietzke, K. R.

    1977-01-01

    This paper summarizes work performed in the estimation of gross social value of timber volume and growth rate information used in making regional harvest decisions in the National Forest System. A model was developed to permit parametric analysis. The problem is formulated as one of finding optimal inventory holding patterns. Public timber management differs from other inventory holding problems in that the inventory, itself, generates value over time in providing recreational, aesthetic and environmental goods. 'Nontimber' demand estimates are inferred from past Forest Service harvest and sales levels. The solution requires a description of the harvest rates which maintain the optimum inventory level. Gross benefits of the Landsat systems are estimated by comparison with Forest Service information gathering models. Gross annual benefits are estimated to be $5.9 million for the MSS system and $7.2 million for the TM system.

  4. Disturbance legacies and climate jointly drive tree growth and mortality in an intensively studied boreal forest

    Energy Technology Data Exchange (ETDEWEB)

    Bond-Lamberty, Benjamin; Rocha, Adrian; Calvin, Katherine V.; Holmes, Bruce; Wang, Chuankuan; Goulden, Michael L.

    2014-01-01

    How will regional growth and mortality change with even relatively small climate shifts, even independent of catastrophic disturbances? This question is particularly acute for the North American boreal forest, which is carbon-dense and subject The goals of this study were to combine dendrochronological sampling, inventory records, and machine-learning algorithms to understand how tree growth and death have changed at one highly studied site (Northern Old Black Spruce, NOBS) in the central Canadian boreal forest. Over the 1999-2012 inventory period, mean DBH increased even as stand density and basal area declined significantly from 41.3 to 37.5 m2 ha-1. Tree mortality averaged 1.4±0.6% yr-1, with most mortality occurring in medium-sized trees. A combined tree ring chronology constructed from 2001, 2004, and 2012 sampling showed several periods of extreme growth depression, with increased mortality lagging depressed growth by ~5 years. Minimum and maximum air temperatures exerted a negative influence on tree growth, while precipitation and climate moisture index had a positive effect; both current- and previous-year data exerted significant effects. Models based on these variables explained 23-44% of the ring-width variability. There have been at least one, and probably two, significant recruitment episodes since stand initiation, and we infer that past climate extremes led to significant NOBS mortality still visible in the current forest structure. These results imply that a combination of successional and demographic processes, along with mortality driven by abiotic factors, continue to affect the stand, with significant implications for our understanding of previous work at NOBS and the sustainable management of regional forests.

  5. 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

  6. Availability of {sup 99}Tc in undisturbed soil cores

    Energy Technology Data Exchange (ETDEWEB)

    Denys, Sebastien; Echevarria, Guillaume E-mail: guillaume.echevarria@ensaia.inpl-nancy.fr; Florentin, Louis; Leclerc-Cessac, Elisabeth; Morel, Jean-Louis

    2003-07-01

    Models for safety assessment of radioactive waste repositories need accurate values of the soil-to-plant transfer of radionuclides. In oxidizing environments, {sup 99}Tc is expected to occur as pertechnetate ({sup 99}TcO{sub 4}{sup -}). Due to its high mobility, leaching of this element in the field might be important, potentially affecting the reliability of estimated transfer parameters of {sup 99}Tc as measured in closed experimental systems such as hydroponics or pot experiments. The aim of this experiment was to measure the leaching of {sup 99}Tc in undisturbed irrigated soil cores under cultivation as well as plant uptake and to study the possible competition between the two transfer pathways. Undisturbed soil cores (50x50 cm) were sampled from a Rendzic Leptosol (R), a colluvial Fluvic Cambisol (F) and a Dystric Cambisol (D) using PVC tubes (three cores sampled per soil type). Each core was equipped with a leachate collector at the bottom, allowing the monitoring of {sup 99}Tc leaching through the cores. Cores were placed in a greenhouse and maize (Zea mays L., cv. DEA, Pioneer[reg]) was sown. After 135 d, maize was harvested and radioactivity determined in both plant and water samples. Results showed that during the growing period, leaching of {sup 99}Tc was limited, due to the high evapotranspiration rate of maize. After harvest, leaching of {sup 99}Tc went on because of the absence of evapotranspiration. Effective uptake (EU) of {sup 99}Tc in leaves and grains was calculated. EU reached 70% of the input in the leaves and was not significantly different among soils. These results confirmed those obtained from pot experiments, even though leaching was allowed to occur in close-to-reality hydraulical conditions. As a consequence, it was concluded that pot experiments are an adequate surrogate for more complex 'close-to-reality' experimental systems for measuring transfer factors.

  7. Where are the forests in the United States "not disturbed" over a quarter century?

    Science.gov (United States)

    Huang, C.; Zhao, F. A.; Goward, S. N.; Schleeweis, K.; Michaelis, A.; Masek, J. G.; Dungan, J. L.; Cohen, W. B.; Moisen, G.; Rishmawi, K.

    2015-12-01

    Forests provide many important ecosystem services. Logging, fire, and other disturbances can disrupt or even diminish the provision of these services. Although many map products and inventory data can be used to estimate the total forested area in the United States, it is not clear how much of the country's forest remained undisturbed in recent decades. Through the North American Forest Dynamics (NAFD) study, we have mapped both disturbed and undisturbed forests over the conterminous United States (CONUS) using sub-annual time series of Landsat observations. The results revealed that 33.6% of the land area of CONUS had forest cover during some or all of the years between 1986 and 2010. About two thirds of the nation's forests remained undisturbed during the 25-year period. Most of these undisturbed forests were distributed in western and northern parts of the eastern US. The percentage of undisturbed forest in the southeastern states were lower, about 50% or less. In these states, much of the undisturbed forest was distributed along riparian zones or in protected areas, including national parks and national forests. In the northeastern and western US, riparian zones did not have a significantly higher proportion of undisturbed forests than non-riparian areas. While most protected areas had a high percentage of undisturbed forests, some of them had lower percentages than the average values of their surrounding regions. Topography may also have played a role in keeping forests "undisturbed". Many ecoregions in the western and northern US had a substantially higher percentage of undisturbed forests at high elevations than at low elevations.

  8. Large impacts of climatic warming on growth of boreal forests since 1960.

    Science.gov (United States)

    Kauppi, Pekka E; Posch, Maximilian; Pirinen, Pentti

    2014-01-01

    Boreal forests are sensitive to climatic warming, because low temperatures hold back ecosystem processes, such as the mobilization of nitrogen in soils. A greening of the boreal landscape has been observed using remote sensing, and the seasonal amplitude of CO2 in the northern hemisphere has increased, indicating warming effects on ecosystem productivity. However, field observations on responses of ecosystem productivity have been lacking on a large sub-biome scale. Here we report a significant increase in the annual growth of boreal forests in Finland in response to climatic warming, especially since 1990. This finding is obtained by linking meteorological records and forest inventory data on an area between 60° and 70° northern latitude. An additional increase in growth has occurred in response to changes in other drivers, such as forest management, nitrogen deposition and/or CO2 concentration. A similar warming impact can be expected in the entire boreal zone, where warming takes place. Given the large size of the boreal biome - more than ten million km2- important climate feedbacks are at stake, such as the future carbon balance, transpiration and albedo.

  9. The Tribal Perspective of Old Growth in Frequent-fire Forests - Its History

    Directory of Open Access Journals (Sweden)

    Victoria Yazzie

    2007-12-01

    Full Text Available Anyone who has not lived in "Indian country" cannot understand just how extensively the United States government and its laws affect Native Americans and their natural resource management. These effects are sobering, and touch upon sensitive issues that all Native Americans hold within us. In this article, I outline the historic cycle of tribal entities, and characterize today's tribal self-determination in forest management. I provide an historical account from the "colonial" period and its use of the Doctrine of Discovery to the relations between the United States government and Native Americans from the 18th through the 20th centuries, during which time Native Americans struggled to establish their legal status as tribes, and solidify their land base to sustain and conserve culturally important lands, including areas of old-growth forests, to the current self-determination and self-governance potential of Indian tribes. More importantly, I discuss the cultural connectivity that Native Americans have to the land, and address the unique inherent right of tribes to integrate this cultural view into current forest management, including the protection of old-growth forests, on their reservations.

  10. 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.

  11. Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

    Directory of Open Access Journals (Sweden)

    D. Tian

    2017-07-01

    Full Text Available Reactive nitrogen (N increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m  ×  20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings, and ground-cover plants (ferns according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height of 5–10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha−1 yr−1 and N100 fertilized plots (100 kg N ha−1 yr−1, while the growth of median and large trees with a DBH of  >  10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical

  12. Growth responses of trees and understory plants to nitrogen fertilization in a subtropical forest in China

    Science.gov (United States)

    Tian, Di; Li, Peng; Fang, Wenjing; Xu, Jun; Luo, Yongkai; Yan, Zhengbing; Zhu, Biao; Wang, Jingjing; Xu, Xiaoniu; Fang, Jingyun

    2017-07-01

    Reactive nitrogen (N) increase in the biosphere has been a noteworthy aspect of global change, producing considerable ecological effects on the functioning and dynamics of the terrestrial ecosystems. A number of observational studies have explored responses of plants to experimentally simulated N enrichment in boreal and temperate forests. Here we investigate how the dominant trees and different understory plants respond to experimental N enrichment in a subtropical forest in China. We conducted a 3.4-year N fertilization experiment in an old-aged subtropical evergreen broad-leaved forest in eastern China with three treatment levels applied to nine 20 m × 20 m plots and replicated in three blocks. We divided the plants into trees, saplings, shrubs (including tree seedlings), and ground-cover plants (ferns) according to the growth forms, and then measured the absolute and relative basal area increments of trees and saplings and the aboveground biomass of understory shrubs and ferns. We further grouped individuals of the dominant tree species, Castanopsis eyrei, into three size classes to investigate their respective growth responses to the N fertilization. Our results showed that the plot-averaged absolute and relative growth rates of basal area and aboveground biomass of trees were not affected by N fertilization. Across the individuals of C. eyrei, the small trees with a DBH (diameter at breast height) of 5-10 cm declined by 66.4 and 59.5 %, respectively, in N50 (50 kg N ha-1 yr-1) and N100 fertilized plots (100 kg N ha-1 yr-1), while the growth of median and large trees with a DBH of > 10 cm did not significantly change with the N fertilization. The growth rate of small trees, saplings, and the aboveground biomass of understory shrubs and ground-cover ferns decreased significantly in the N-fertilized plots. Our findings suggested that N might not be a limiting nutrient in this mature subtropical forest, and that the limitation of other nutrients in the forest

  13. Restoring hydrology and old-growth structures in a former production forest

    DEFF Research Database (Denmark)

    Mazziotta, Adriano; Heilmann-Clausen, Jacob; Bruun, Hans Henrik

    2016-01-01

    The biodiversity value of production forests is substantially lower than that of natural forests. This is related to differences in hydrology, stand age and amounts of old trees and deadwood. Using a predictive model framework we show that restoring hydrology and old-growth characteristics...... to restore hydrology and old-growth structure. We collected presence/absence data for four organism groups (vascular plants, epiphytic bryophytes and lichens, wood-inhabiting fungi) and measured environmental variables associated with species occurrence and influenced by restoration (dead or living tree...... characteristics, stand age, water level). We investigated biodiversity consequences of restoration towards pristine environmental characteristics by using a space-for-time substitution model. We evaluated how and through what mechanisms species richness is likely to react when pre-forestry hydrological conditions...

  14. Ground cover in old-growth forests of the central hardwood region

    Science.gov (United States)

    Martin A. Spetich; Stephen R. Shifley; George R. Parker; Felix, Jr. Ponder

    1997-01-01

    Differences in ground cover (percent cover of litter, percent cover of vegetation and litter weight) in old-growth forests across this region are not well understood. We initiated a long-term study in a three-state region to enhance knowledge in this area. We present baseline results for ground cover and compare these data across productivity regions. Thirty 0.25-ac (0...

  15. Stand Dynamics in an Old-Growth Hardwood Forest in Southern Illinois, USA

    Science.gov (United States)

    James J. Zaczek; John W. Groninger; J. W. Van Sambeek

    2002-01-01

    Kaskaskia Woods, a 7.4-ha old-growth hardwood forest in southern Illinois, USA, has been managed as a natural area and protected from disturbance since 1933. In 1935, eight 0.1-ha plots were installed and all trees 4 cm dbh or larger were tagged and inventoried. Trees were remeasured for survival, ingrowth (new trees >4 cm), and diameter (dbh) in 1940, 1958, 1965,...

  16. Nutrient status and plant growth effects of forest soils in the Basin of Mexico

    Science.gov (United States)

    Mark E. Fenn; V.M. Perea-Estrada; L.I. de Bauer; M. Pérez-Suárez; D.R. Parker; V.M. Cetina-Alcalá

    2006-01-01

    The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and...

  17. Stimulating seedling growth in early stages of secondary forest succession: a modeling approach to guide tree liberation

    NARCIS (Netherlands)

    Kuijk, M.; Anten, N.P.R.; Oomen, R.J.; Schieving, F.

    2014-01-01

    Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target

  18. Stimulating seedling growth in early stages of secondary forest succession : a modeling approach to guide tree liberation

    NARCIS (Netherlands)

    van Kuijk, Marijke; Anten, Niels P. R.; Oomen, Roelof J.; Schieving, Feike

    2014-01-01

    Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target

  19. Determination Of Reference-Site Based On The Cs-137 Distribution At Soil Layer From A Few Undisturbed Location

    International Nuclear Information System (INIS)

    Suhartini, Nita; Darman; Haryono; Djarot, A.S.

    2000-01-01

    Radiogenic 137 Cs content of a soil used to estimate the amount of erosion in area, with respect to a reference site. The investigation aimed to determined the reference-site from several of undisturbed locations based on the 137 Cs distribution of the soil layer. The location are a forest at West Java, namely Gn Pangrango - Cibodas, Gn. Masigit Kareumbi and Gn. Kamojang Garut. The points sampling were chosen at an open and very flat area where the possibility of erosion is very low. The samples were taken using Scrapper (20x50) cm, and the layer thickness is 2 cm with sampling depth is 20 cm. The result showed that the best location which could be used as a reference-site is the forest ata Gn. Pangranggo - Cibodas, having the men value of 137 Cs activity is 520 Bq/m 2

  20. Possibilities and limitations of using historic provenance tests to infer forest species growth responses to climate change

    Science.gov (United States)

    Laura P. Leites; Gerald E. Rehfeldt; Andrew P. Robinson; Nicholas L. Crookston; Barry Jaquish

    2012-01-01

    Under projected changes in global climate, the growth and survival of existing forests will depend on their ability to adjust physiologically in response to environmental change. Quantifying their capacity to adjust and whether the response is species- or population-specific is important to guide forest management strategies. New analyses of historic provenance tests...

  1. Effects of soil compaction on residual stand growth in central Appalachian hardwood forest: a preliminary case study

    Science.gov (United States)

    Jingxin Wang; Chris LeDoux; Michael Vanderberg; Li Yaoxiang

    2006-01-01

    A preliminary study that quantified the impacts of soil compaction on residual tree growth associated with ground-based skidding traffic intensity and turn payload size was investigated in the central Appalachian hardwood forest. The field study was carried out on a 20-acre tract of the West Virginia University Research Forest. Skid trails were laid out in 170' -...

  2. Managing heart rot in live trees for wildlife habitat in young-growth forests of coastal Alaska

    Science.gov (United States)

    Paul E. Hennon; Robin L. Mulvey

    2014-01-01

    Stem decays of living trees, known also as heart rots, are essential elements of wildlife habitat, especially for cavity-nesting birds and mammals. Stem decays are common features of old-growth forests of coastal Alaska, but are generally absent in young, managed forests. We offer several strategies for maintaining or restoring fungal stem decay in these managed...

  3. Nutrient status and plant growth effects of forest soils in the Basin of Mexico

    International Nuclear Information System (INIS)

    Fenn, M.E.; Perea-Estrada, V.M.; Bauer, L.I. de; Perez-Suarez, M.; Parker, D.R.; Cetina-Alcala, V.M.

    2006-01-01

    The nutrient status of forest soils in the Mexico City Air Basin was evaluated by observing plant growth responses to fertilization with N, P or both nutrients combined. P deficiency was the most frequent condition for soil from two high pollution sites and N deficiency was greatest at a low N deposition site. Concentrations of Pb and Ni, and to a lesser extent Zn and Co, were higher at the high pollution sites. However, positive plant growth responses to P and sometimes to N, and results of wheat root elongation bioassays, suggest that heavy metal concentrations were not directly phytotoxic. Further studies are needed to determine if heavy metal toxicity to mycorrhizal symbionts of eucalyptus (Eucalyptus camaldulensis Dehnh.) from high pollution sites may explain the P deficiency and stunted growth. P deficiency is expected to limit the capacity for biotic N retention in N saturated forested watersheds in the Basin of Mexico dominated by Andisols. - Plant response to N deposition may be limited by P limitation in forests growing on Andisol soils in the Basin of Mexico

  4. Resilience of ponderosa and lodgepole pine forests to mountain pine beetle disturbance and limited regeneration

    Science.gov (United States)

    Briggs, Jenny S.; Hawbaker, Todd J.; Vandendriesche, Don

    2015-01-01

    After causing widespread mortality in lodgepole pine forests in North America, the mountain pine beetle (MPB) has recently also affected ponderosa pine, an alternate host species that may have different levels of resilience to this disturbance. We collected field data in ponderosa pine- and lodgepole pine-dominated forests attacked by MPB in Colorado and then simulated stand growth over 200 years using the Forest Vegetation Simulator. We compared scenarios of no disturbance with scenarios of MPB-caused mortality, both with and without regeneration. Results indicated that basal area and tree density recovered to predisturbance levels relatively rapidly (within 1‐8 decades) in both forest types. However, convergence of the disturbed conditions with simulated undisturbed conditions took longer (12‐20+ decades) and was delayed by the absence of regeneration. In MPB-affected ponderosa pine forests without regeneration, basal area did not converge with undisturbed conditions within 200 years, implying lower resilience in this ecosystem. Surface fuels accumulated rapidly in both forest types after MPB-induced mortality, remaining high for 3‐6 decades in simulations. Our results suggest that future patterns of succession, regeneration, fuel loading, climate, and disturbance interactions over long time periods should be considered in management strategies addressing MPB effects in either forest type, but particularly in ponderosa pine.

  5. Allometry and growth of six tree species in a terra firme forest in colombian amazonia

    International Nuclear Information System (INIS)

    Giraldo Pamplona Wilson A; Dairon, Alvaro; Cardenas Montoya J, Duque

    2011-01-01

    In this study carried out in the Amacayacu National Park in the Colombian Amazonia, we assessed the allometric relationship among different tree structural variables and the growth in diameter and biomass of six species classified according to their wood specific gravity. The tree species chosen were Eschweilera rufolia, Eschweilera itayensis, Conceveiba guianensis, Otoba parvifolia, Pseudolmedia laevis, and Apeiba aspera. The dbh was the most important structural explanatory variable. Regarding the total height dbh model, the allometric coefficient b changed between species showing a trend to increase, and thus a taper decrease, proportional to. There were o significant differences in diameter growth between species (P=0.119, F=1.80) or functional groups (P=0.153, F= 1.19). Likewise, biomass growth did not show significant differences neither between species (P=0.0784, F=2.05) nor functional groups (P=0.0711, F=2.71). However, there was a positive trend between and diameter growth and a negative one between and biomass growth. The results of this study suggest that this forest is recovering in biomass at a constant rate independent of the patch age, which emphasizes on the importance of pioneer species and gap formation on the carbon dynamics and the species coexistence in Amazonian tierra firme forests.

  6. 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...

  7. Growth dynamics of fine roots in a coniferous fern forest site close to Forsmark in the central part of Sweden

    Energy Technology Data Exchange (ETDEWEB)

    Persson, Hans; Stadenberg, Ingela (SLU, Dept. of Ecology and Environmental Research, Uppsala (Sweden))

    2007-12-15

    ) varied between 226, 321, 176 and 299 g/m2. The total quantity of fine roots (live + dead) amounted to 543, 434, 314 and 546 g/m2. Considerable quantities of fine roots (< 1 mm in diameter) were attributed to field-layer species (about 18% of the total biomass during the whole period of investigation). The turnover rate (the rate of construction of new roots) for tree fine roots < 1 mm in diameter amounted to at least the size of the average fine-root biomass. Our methods of estimating fine-root production and mortality, involved periodic measurements of live and dead dry weight of the fine roots from sequential core samples of the forest soil. The collected data give a proper and instant measure of the spatial and temporal distribution of fine roots in the undisturbed soil-profile. Data from other fine-root investigations suggest turnover rates in agreement with our present findings. Differences between root growth and turnover should be expected between trees of different age, tree species and different forest sites, but also between different years. Substantial variations in fine-root biomass, necromass and live/dead ratios are found in different forest sites. Correct methods for estimating the amount of live and dead fine-roots in the soil at regular time intervals are essential for any calculation of fine-root turnover. Definition of root vitality differs in literature, making it difficult to compare results from different root investigators. Our investigation clarifies the importance of using distinct morphological criteria when sorting fine roots into live and dead tissues. Our data suggest that the often-reported discrepancy in the data of fine roots in literature most frequently is due to lack of precision in the detection the vitality of the excavated root-fragments. The live/death ratio of the fine roots in this context is reflecting the vitality of the fine roots, both temporarily and spatially in the soil profile. The live/dead ratio seems to be a most

  8. Increase of an introduced bird competitor in old-growth forest associated with restoration

    Directory of Open Access Journals (Sweden)

    Leonard Freed

    2012-05-01

    Full Text Available Many successful invasions involve long initial periods in which the invader exists at low densities followed by sudden population increases. The reasons for such time-lags remain poorly understood. Here we document a sudden increase in density of the introduced Japanese white-eye (Zosterops japonicus in a restoration area contiguous with old-growth forest at Hakalau Forest National Wildlife Refuge on the Island of Hawaii. The refuge, with very high density of native birds, existed in a pocket of low white-eye density that persisted for at least 20 years since the late 1970s. The refuge began an extensive native trees restoration project in 1989 within a 1314 ha abandoned pasture above old-growth forest. This area was soon colonized by white-eyes and their population grew exponentially once the trees had grown tall enough to develop a canopy. This increase was in turn followed by significantly more white-eyes in the open and closed forests adjacent to the restoration area. Competition between white-eyes and native species was documented on study sites within these forests. Density data indicate that competition was more widespread, with loss of tens of thousands of native birds in the 5371 ha area surveyed. Our results are consistent with the view that ecological barriers may delay the population increase of invaders and that human-derived activities may help invaders cross these barriers by creating new ecological opportunities. Control of white-eye numbers may be essential for recovery of native species.

  9. Drought as a driver of declining boreal forest growth: Integrating forest inventory measurements with models to gain insight into underlying mechanisms

    Science.gov (United States)

    Trugman, A. T.; Medvigy, D.; Anderegg, W.; Caspersen, J.; Zeng, H.; Pacala, S. W.

    2016-12-01

    Boreal forests contain over 30% of Earth's terrestrial carbon and are an important component of the land carbon sink. However, the future ability of the boreal forest to maintain a net carbon sink is uncertain and depends on potentially compensating interactions of CO2 fertilization, warmer temperatures, and hotter drought conditions. Observational studies have attributed drought as a major driver of recent declines in growth and increases in mortality in many parts of the North American boreal forest. Yet, most vegetation models have a simplistic representation of vegetation water stress and fail to capture drought-associated growth and mortality trends, impacting our ability to accurately forecast the effects of climate change on the boreal forest. Here, we show additional evidence for widespread declines in boreal tree growth and increasing insect-related mortality in aspen trees based on a mixed model analysis of the Cooperative Alaska Forest Inventory. Our findings indicate that the growth decline is controlled by high midsummer potential evapotranspiration that overpowers any CO2 fertilization signal. We also observe a possible shift in the distribution of angiosperm and gymnosperm, a biological transition that could impact long-term local carbon dynamics. Using insight gained from our mixed model analysis, we perform a regional-scale model evaluation using the boreal forest version of Ecosystem Demography model 2 that includes a dynamic soil organic layer, 7 boreal-specific plant functional types, and a fully mechanistic plant hydraulic scheme. We then use both the Alaskan and Canadian Forest Inventories to constrain our hypotheses and assess whether drought related growth declines can be better attributed to tree drought response from (1) carbon starvation, (2) permanent damage of hydraulic machinery, or (3) delayed recovery of hydraulic machinery. Under each of these scenarios we forecast how drought potentially impacts decadal-scale boreal carbon dynamics.

  10. Growth Model of Pine (Pinus merkusii Jungh. Et de Vriese Stand on Community Forest in Tana Toraja Regency

    Directory of Open Access Journals (Sweden)

    Melewanto Patabang

    2014-04-01

    Full Text Available Growth modeling and yield simulation of forest is a very important aspect in forest management including community forests. Stand growth model is an abstraction of the dynamic nature of a forest stand, including growth, ingrowths, mortality, and other changes in the structure and composition of the stand. In forest management, growth estimation plays an important role in supporting the sustainability of the benefits value of the community forests. The objectives of the research were to find out the stand growth model and the potential of community's pine forest. The study was conducted at the location of the community pine forests in District Mengkendek Tana Toraja Regency. Sample location, as representative of stand age classes that distribute on some villages in Mengkendek District, were selected by purposive sampling.The study results indicate that the most suitable model for upper trees mean height (H is Weibull Model, for growth diameter and growth volume is Logistic Model . The stand mean height (h can be presented as a function of H and Relative Spacing Ratio (Sr on the basis of function log Sr = 0,197 – 0,653 log H, then the tree volume, can be estimated on the basis of function log V = -1,70 + 0,94logD + 1,50logh, and then the growth function of volume on the basis of function V = 1.008 / 1 + 251.322 exp(-0.373t. Further, the maximum value of stand Annual Increment was 18 m3ha-1year-1, attained at the age of 20 years.

  11. Who is the new sheriff in town regulating boreal forest growth?

    Science.gov (United States)

    Park Williams, A.; Xu, Chonggang; McDowell, Nate G.

    2011-12-01

    Climate change appears to be altering boreal forests. One recently observed symptom of these changes has been an apparent weakening of the positive relationship between high-latitude boreal tree growth and temperature at some sites (D'Arrigo et al 2008). This phenomenon is referred to as the 'divergence problem' or 'divergence effect' and is thought to reflect a non-linear relationship between temperature and tree growth, where recent warming has allowed other factors besides growing-season temperature to emerge as dominant regulators of annual growth rates. Figure 1 demonstrates this divergence phenomenon with records of tree-ring widths collected from 59 populations of white spruce in Alaska 1. Key tendencies among these populations include: (1) growth is most sensitive to temperature during relatively cold growing seasons (figure 1(a)), (2) populations at colder sites are more sensitive to temperature than those at warmer sites are (figure 1(a)), and (3) growth at warmer sites may respond negatively to increased temperature beyond some optimal growing-season temperature (figure 1(b)). Since temperature is rising rapidly at high latitudes, one interpretation of figures 1(a) and (b) is that warming has promoted increased growth at colder sites, but caused growth to plateau or slow at warmer sites. Corroborating this interpretation, satellite imagery and tree-ring data indicate increasing vegetation productivity near the forest-tundra boundary but declining productivity in warmer regions within forest interiors (e.g., Bunn and Goetz 2006, Beck and Goetz 2011, Beck et al 2011, Berner et al 2011). Will continued warming cause a northward migration of boreal forests, with mortality in the warmer, southern locations and expansion into the colder tundra? This question is difficult to answer because many factors besides temperature influence boreal forest dynamics. Widespread productivity declines within interior boreal forests appear to be related to warming

  12. Soil biota effects on clonal growth and flowering in the forest herb Stachys sylvatica

    Science.gov (United States)

    de la Peña, Eduardo; Bonte, Dries

    2011-03-01

    The composition of a soil community can vary drastically at extremely short distances. Therefore, plants from any given population can be expected to experience strong differences in belowground biotic interactions. Although it is well recognized that the soil biota plays a significant role in the structure and dynamics of plant communities, plastic responses in growth strategies as a function of soil biotic interactions have received little attention. In this study, we question whether the biotic soil context from two forest associated contrasting environments (the forest understory and the hedgerows) determines the balance between clonal growth and flowering of the perennial Stachys sylvatica. Using artificial soils, we compared the growth responses of this species following inoculation with the mycorrhizal and microbial community extracted either from rhizospheric soil of the forest understory or from the hedgerows. The microbial context had a strong effect on plant functional traits, determining the production of runners and inflorescences. Plants inoculated with the hedgerow community had a greater biomass, larger number of runners, and lower resource investment in flower production than was seen in plants inoculated with the understory microbial community. The obtained results illustrate that belowground biotic interactions are essential to understand basic plastic growth responses determinant for plant establishment and survival. The interactions with microbial communities from two contrasting habitats resulted in two different, and presumably adaptive, growth strategies that were optimal for the conditions prevalent in the environments compared; and they are as such an essential factor to understand plant-plant, plant-animal interactions and the dispersal capacities of clonal plants.

  13. Downstream impacts of a Central Amazonian hydroelectric dam on tree growth and mortality in floodplain forests

    Science.gov (United States)

    Resende, A. F. D.; Silva, T. S. F.; Silva, J. D. S.; Piedade, M. T. F.; Streher, A. S.; Ferreira-Ferreira, J.; Schongart, J.

    2017-12-01

    The flood pulse of large Amazonian Rivers is characterized by predictable high- and low-water periods during the annual cycle, and is the main driving force in the floodplains regulating decomposition, nutrient cycles, productivity, life cycles and growth rhythms of floodplains' biota. Over at least 20 millions of years, tree species in these ecosystems developed complex adaptative mechanisms to tolerate flooding, such as the tree species Macrolobium acaciifolium (Fabaceae) and Eschweilera tenuifolia (Lecythidaceae) occupying the lower topographic positions in the floodplain forests along the oligothrophic black-water rivers. Tree growth occurs mainly during terrestrial phase, while during the aquatic phase the anoxic conditions result into a cambial dormancy and formation of annual tree rings. The hydroelectric dam Balbina which was installed in the Uatumã River (central Amazonia) during the 1980s altered significantly the flood pulse regime resulting into higher minimum and lower maximum annual water levels. The suppression of the terrestrial phase caused large-scale mortality of flood-adapted trees growing on the lower topographic positions, as evidenced by radiocarbon dating and cross-dating techniques (dendrochronology). In this study we estimated the extension of dead forests using high resolution ALOS/PALSAR radar images, for their detection along a fluvial distance of more than 280 km downstream of the power plant. Further we analyzed tree growth of 60 living individuals of E. tenuifolia by tree-ring analyses comparing the post- and pre-dam periods. We evaluated the impacts of the altered hydrological regime on tree growth considering ontogenetic effects and the fluvial distance of the trees to the dam. Since the Balbina power plant started operating the associated igapó forests lost about 11% of its cover. We found a significant reduction of tree growth of E. tenuifolia during the post-dam period as a consequence of the increasing aquatic phase duration

  14. Foliar growth of Eriocnema fulva Naudin (Melastomataceae in a forest fragment in southeastern Brazil

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    PM. Andrade

    Full Text Available Eriocnema fulva Naudin is an endangered herbaceous, perennial, iteroparous, evergreen species geographically restricted to southeastern-center Minas Gerais State, SE Brazil. The individuals occur as patches on rocky riverbanks shaded by seasonal semideciduous Atlantic forest; they are fixed by roots and have a pending stem. Aiming to investigate leaf development and its importance for individual survival, fifteen contiguous plots (1 x 1 m were set down in Jambreiro Forest (19° 58’-59’ S and 43° 52’-55’ W, 800-1100 m altitude, in the municipality of Nova Lima. A total of 260 individuals with the largest leaf blade length > 1 cm was tagged and measured in 1997, 1998, and 1999. Leaf expansion was recorded each month during 26 months until April 2000. Plant size was measured through leaf blade length, petiole length, stem length, and number of leaves. Significant changes were detected only after two years, thus indicating that plant growth is slow. The proportion of surviving leaves after two years was 60%. Total blade expansion took over 14 months, a slow growth rate when compared to leaves of other tropical forest canopy and understory species. Long leaf lifespans are to be found in plants exhibiting slow growth, and we observed that some leaves lived longer than three years. Petiole growth can help to better position the leaf in the search for light, thus contributing to the growth and survival of the plant. The relationships among size measures were significant, reinforcing the great contribution of leaf size for plant size. The age of the largest individual was estimated as 36 years based on the median annual leaf production rate.

  15. Foliar growth of Eriocnema fulva Naudin (Melastomataceae) in a forest fragment in southeastern Brazil.

    Science.gov (United States)

    Andrade, P M; Santos, F A M; Martins, F R

    2008-02-01

    Eriocnema fulva Naudin is an endangered herbaceous, perennial, iteroparous, evergreen species geographically restricted to southeastern-center Minas Gerais State, SE Brazil. The individuals occur as patches on rocky riverbanks shaded by seasonal semideciduous Atlantic forest; they are fixed by roots and have a pending stem. Aiming to investigate leaf development and its importance for individual survival, fifteen contiguous plots (1 x 1 m) were set down in Jambreiro Forest (19 degrees 58'-59' S and 43 degrees 52'-55' W, 800-1100 m altitude), in the municipality of Nova Lima. A total of 260 individuals with the largest leaf blade length > or = 1 cm was tagged and measured in 1997, 1998, and 1999. Leaf expansion was recorded each month during 26 months until April 2000. Plant size was measured through leaf blade length, petiole length, stem length, and number of leaves. Significant changes were detected only after two years, thus indicating that plant growth is slow. The proportion of surviving leaves after two years was 60%. Total blade expansion took over 14 months, a slow growth rate when compared to leaves of other tropical forest canopy and understory species. Long leaf lifespans are to be found in plants exhibiting slow growth, and we observed that some leaves lived longer than three years. Petiole growth can help to better position the leaf in the search for light, thus contributing to the growth and survival of the plant. The relationships among size measures were significant, reinforcing the great contribution of leaf size for plant size. The age of the largest individual was estimated as 36 years based on the median annual leaf production rate.

  16. Multidecadal stability in tropical rain forest structure and dynamics across an old-growth landscape.

    Science.gov (United States)

    Clark, David B; Clark, Deborah A; Oberbauer, Steven F; Kellner, James R

    2017-01-01

    Have tropical rain forest landscapes changed directionally through recent decades? To answer this question requires tracking forest structure and dynamics through time and across within-forest environmental heterogeneity. While the impacts of major environmental gradients in soil nutrients, climate and topography on lowland tropical rain forest (TRF) structure and function have been extensively analyzed, the effects of the shorter environmental gradients typical of mesoscale TRF landscapes remain poorly understood. To evaluate multi-decadal performance of an old-growth TRF at the La Selva Biological Station, Costa Rica, we established 18 0.5-ha annually-censused forest inventory plots in a stratified-random design across major landscape edaphic gradients. Over the 17-year study period, there were moderate differences in stand dynamics and structure across these gradients but no detectable difference in woody productivity. We found large effects on forest structure and dynamics from the mega-Niño event at the outset of the study, with subdecadal recovery and subsequent stabilization. To extend the timeline to >40 years, we combined our findings with those from earlier studies at this site. While there were annual to multiannual variations in the structure and dynamics, particularly in relation to local disturbances and the mega-Niño event, at the longer temporal scale and broader spatial scale this landscape was remarkably stable. This stability contrasts notably with a current hypothesis of increasing biomass and dynamics of TRF, which we term the Bigger and Faster Hypothesis (B&FHo). We consider possible reasons for the contradiction and conclude that it is currently not possible to independently assess the vast majority of previously published B&FHo evidence due to restricted data access.

  17. Quantitative imaging of cation adsorption site densities in undisturbed soil

    Science.gov (United States)

    Keck, Hannes; Strobel, Bjarne W.; Gustafsson, Jon-Petter; Koestel, John

    2017-04-01

    The vast majority of present soil system models assume a homogeneous distribution and accessibility of cation adsorption sites (CAS) within soil structural units like e.g. soil horizons. This is however in conflict with several recent studies finding that CAS in soils are not uniformly but patchily distributed at and below the cm-scale. It is likely that the small-scale distribution of CAS has significant impact on the performance of these models. However, systematic approaches to map CAS densities in undisturbed soil with 3-D resolution that could lead to respective model improvements are still lacking. We therefore investigated the 3-D distribution of the CAS in undisturbed soils using X-ray scanning and barium ions as a contrast agent. We appraised the validity of the approach by comparing X-ray image-derived cation exchange coefficients (CEC) with ones obtained using the ammonium acetate method. In the process, we evaluated whether there were larger CAS concentrations at aggregate and biopore boundaries as it is often hypothesized. We sampled eight small soil cores (approx. 10 ccm) from different locations with contrasting soil texture and organic matter contents. The samples were first saturated with a potassium chloride solution (0.1 mol per liter), whereupon a 3-D X-ray image was taken. Then, the potassium chloride solution was flushed out with a barium chloride solution (0.3 mol per liter) with barium replacing the potassium from the CAS due to its larger exchange affinity. After X-ray images as well as electrical conductivity in the effluent indicated that the entire sample had been saturated with the barium chloride, the sample was again rinsed using the potassium chloride solution. When the rinsing was complete a final 3-D X-ray image was acquired. The difference images between final and initial 3-D X-ray images were interpreted as depicting the adsorbed barium as the density of barium exceeds the one of potassium by more than 2 times. The X-ray image

  18. Nitrogen limitation of growth and nutrient dynamics in a disturbed mangrove forest, Indian River Lagoon, Florida

    Science.gov (United States)

    Feller, Ilka C.; Whigham, D.F.; McKee, K.L.; Lovelock, C.E.

    2003-01-01

    The objectives of this study were to determine effects of nutrient enrichment on plant growth, nutrient dynamics, and photosynthesis in a disturbed mangrove forest in an abandoned mosquito impoundment in Florida. Impounding altered the hydrology and soil chemistry of the site. In 1997, we established a factorial experiment along a tree-height gradient with three zones, i.e., fringe, transition, dwarf, and three fertilizer treatment levels, i.e., nitrogen (N), phosphorus (P), control, in Mosquito Impoundment 23 on the eastern side of Indian River. Transects traversed the forest perpendicular to the shoreline, from a Rhizophora mangle-dominated fringe through an Avicennia germinans stand of intermediate height, and into a scrub or dwarf stand of A. germinans in the hinterland. Growth rates increased significantly in response to N fertilization. Our growth data indicated that this site is N-limited along the tree-height gradient. After 2 years of N addition, dwarf trees resembled vigorously growing saplings. Addition of N also affected internal dynamics of N and P and caused increases in rates of photosynthesis. These findings contrast with results for a R. mangle-dominated forest in Belize where the fringe is N-limited, but the dwarf zone is P-limited and the transition zone is co-limited by N and P. This study demonstrated that patterns of nutrient limitation in mangrove ecosystems are complex, that not all processes respond similarly to the same nutrient, and that similar habitats are not limited by the same nutrient when different mangrove forests are compared.

  19. Changes in plant species composition along an elevation gradient in an old-growth bottomland hardwood-Pinus taeda forest in southern Arkansas

    Science.gov (United States)

    Adrian G. Grell; Michael G. Shelton; Eric Heitzman

    2005-01-01

    Old-growth bottomland hardwood-Pinus taeda L. forests are rare in Arkansas, and the complex relationships between plant communities and environmental conditions have not been well described in these forests. To investigate these relationships, a digital elevation model was developed for a 16.2 ha old-growth bottomland hardwood-Pinus taeda forest in...

  20. Functional strategies of tropical dry forest plants in relation to growth form and isotopic composition

    Science.gov (United States)

    Santiago, L. S.; Silvera, K.; Andrade, J. L.; Dawson, T. E.

    2017-11-01

    Tropical dry forests (TDFs) undergo a substantial dry season in which plant species must endure several months of drought. Although TDFs support a diverse array of plant growth forms, it is not clear how they vary in mechanisms for coping with seasonal drought. We measured organic tissue stable isotopic composition of carbon (δ13C) and nitrogen (δ15N) across six plant growth forms including epiphytes, terrestrial succulents, trees, shrubs, herbs, and vines, and oxygen (δ18O) of four growth forms, to distinguish among patterns of resource acquisition and evaluate mechanisms for surviving annual drought in a lowland tropical dry forest in Yucatan, Mexico. Terrestrial succulent and epiphyte δ13C was around –14‰, indicating photosynthesis through the Crassulacean acid metabolism pathway, and along with one C4 herb were distinct from mean values of all other growth forms, which were between –26 and –29‰ indicating C3 photosynthesis. Mean tissue δ15N across epiphytes was –4.95‰ and was significantly lower than all other growth forms, which had values around +3‰. Tissue N concentration varied significantly among growth forms with epiphytes and terrestrial succulents having significantly lower values of about 1% compared to trees, shrubs, herbs and vines, which were around 3%. Tissue C concentration was highest in trees, shrubs and vines, intermediate in herbs and epiphytes and lowest in terrestrial succulents. δ18O did not vary among growth forms. Overall, our results suggest several water-saving aspects of resource acquisition, including the absolute occurrence of CAM photosynthesis in terrestrial succulents and epiphytes, high concentrations of leaf N in some species, which may facilitate CO2 drawdown by photosynthetic enzymes for a given stomatal conductance, and potentially diverse N sources ranging from atmospheric N in epiphytes with extremely depleted δ15N values, and a large range of δ15N values among trees, many of which are legumes and

  1. TREE DIAMETER GROWTH FOLLOWING SILVICULTURAL TREATMENTS IN A SEMI-DECIDUOUS SECONDARY FOREST IN CENTRAL BRAZIL

    Directory of Open Access Journals (Sweden)

    Fábio Venturoli

    2015-03-01

    Full Text Available In the Cerrado biome of Brazil, savannas and dry forests are intimately linked and form mosaics. These forests are composed of species of high commercial value, well accepted in the timber market, which causes intensive deforestation on the remaining vegetation. Thus, the management of these forests is an important alternative to reduce deforestation in the remaining vegetation. The objective of this study was to analyze the response of tree species in relation to silvicultural treatments of competition and liana cutting in a semi-deciduous forest in Central Brazil. The results showed that community basal area increased 24% over 4.8 years and the median periodic annual increment in diameter was about 20% higher in plots with silvicultural treatments: 2.9 mm.yr-1 in the control compared to 3.2 mm.yr-1 to 3.6 mm.yr-1 between treatments. This study demonstrated that it is possible to increase the rates of radial growth through silvicultural techniques.

  2. Looking for age-related growth decline in natural forests: unexpected biomass patterns from tree rings and simulated mortality.

    Science.gov (United States)

    Foster, Jane R; D'Amato, Anthony W; Bradford, John B

    2014-05-01

    Forest biomass growth is almost universally assumed to peak early in stand development, near canopy closure, after which it will plateau or decline. The chronosequence and plot remeasurement approaches used to establish the decline pattern suffer from limitations and coarse temporal detail. We combined annual tree ring measurements and mortality models to address two questions: first, how do assumptions about tree growth and mortality influence reconstructions of biomass growth? Second, under what circumstances does biomass production follow the model that peaks early, then declines? We integrated three stochastic mortality models with a census tree-ring data set from eight temperate forest types to reconstruct stand-level biomass increments (in Minnesota, USA). We compared growth patterns among mortality models, forest types and stands. Timing of peak biomass growth varied significantly among mortality models, peaking 20-30 years earlier when mortality was random with respect to tree growth and size, than when mortality favored slow-growing individuals. Random or u-shaped mortality (highest in small or large trees) produced peak growth 25-30% higher than the surviving tree sample alone. Growth trends for even-aged, monospecific Pinus banksiana or Acer saccharum forests were similar to the early peak and decline expectation. However, we observed continually increasing biomass growth in older, low-productivity forests of Quercus rubra, Fraxinus nigra, and Thuja occidentalis. Tree-ring reconstructions estimated annual changes in live biomass growth and identified more diverse development patterns than previous methods. These detailed, long-term patterns of biomass development are crucial for detecting recent growth responses to global change and modeling future forest dynamics.

  3. Initial growth of six forest tree species in differents spacing conditions

    Directory of Open Access Journals (Sweden)

    Daniel Ferreira do Nascimento

    2012-03-01

    Full Text Available This work veriflied the influence of planting spacing on the initial growth of six forest species, at the age of 22 months, in plantations of forest recomposition in the Guandu River Basin. The experiment was installed in the SFE - thermoelectric power plants Barbosa Lima Sobrinho, located in the City of Seropédica-RJ. Forty eight tree species were planted, using the spacings, 1.0 x 1.0, 1.5 x 1.5, 2.0 and 2.0 x 3.0 x 2.0 m, which are the study treatments. At 22 months after planting, it was evaluated the growth in height, diameter at ground level (DNS and area of the canopy for the species, Anadenanthera macrocarpa Benth. Brenan (angico vermelho, Schinus terebinthifolius Raddi (aroeira pimenteira, Schizolobium parahyba Blake (guapuruvu Chorisia speciosa St. Hill (paineira, Cordia sp. (babosa branca and Inga marginata (ingá. It was found that the studied species behaved in a different way in the differents spacing of planting, and that the planting density significantly influenced on the initial growth of all the species. In general, in wider planting spacings, the plants had higher growth.

  4. Texas' forests, 2008

    Science.gov (United States)

    James W. Bentley; Consuelo Brandeis; Jason A. Cooper; Christopher M. Oswalt; Sonja N. Oswalt; KaDonna Randolph

    2014-01-01

    This bulletin describes forest resources of the State of Texas at the time of the 2008 forest inventory. This bulletin addresses forest area, volume, growth, removals, mortality, forest health, timber product output, and the economy of the forest sector.

  5. Density, ages, and growth rates in old-growth and young-growth forests in coastal Oregon

    Science.gov (United States)

    Tappeiner, J. C.; Huffman, D.; Spies, T.; Bailey, John D.

    1997-01-01

    We studied the ages and diameter growth rates of trees in former Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) old-growth stands on 10 sites and compared them with young-growth stands (50-70 years old, regenerated after timber harvest) in the Coast Range of western Oregon. The diameters and diameter growth rates for the first 100 years of trees in the old-growth stands were significantly greater than those in the young-growth stands. Growth rates in the old stands were comparable with those from long-term studies of young stands in which density is about 100-120 trees/ha; often young-growth stand density is well over 500 trees/ha. Ages of large trees in the old stands ranged from 100 to 420 years; ages in young stands varied by only about 5 to 10 years. Apparently, regeneration of old-growth stands on these sites occurred over a prolonged period, and trees grew at low density with little self-thinning; in contrast, after timber harvest, young stands may develop with high density of trees with similar ages and considerable self-thinning. The results suggest that thinning may be needed in dense young stands where the management objective is to speed development of old-growth characteristics.

  6. Timing of Drought Triggers Distinct Growth Responses in Holm Oak: Implications to Predict Warming-Induced Forest Defoliation and Growth Decline

    Directory of Open Access Journals (Sweden)

    J. Julio Camarero

    2015-05-01

    Full Text Available Droughts negatively impact forests by reducing growth and increasing defoliation leading to forest dieback as the climate becomes warmer and drier. However, the timing and severity of droughts determine how differently or intensively water shortage affects primary (shoot and leaf formation and secondary growth (stem radial growth based on tree-ring widths. We compare the impact of two severe droughts (2005, 2012, showing different climatic characteristics on the growth responses of three Mediterranean holm oak stands in northeastern Spain. We also quantify climate trends and drought severity. Then, we use remote sensing data to infer how those droughts impacted forest productivity. Both droughts were characterized by warm and dry spring conditions leading to reduced budburst, low shoot production, asynchrony in primary growth and decreased productivity and scarce radial growth, particularly in 2005. However, defoliation peaked in 2012 when radial growth showed minimum values and early spring and late summer temperatures reached maximum values. We discuss how uncoupled and resilient are the responses of primary and secondary growth to drought. Finally, these findings are used to gain insight into the drought-related drivers of defoliation in Spanish holm oak forests.

  7. Liana infestation impacts tree growth in a lowland tropical moist forest

    Directory of Open Access Journals (Sweden)

    G. M. F. van der Heijden

    2009-10-01

    Full Text Available Ecosystem-level estimates of the effect of lianas on tree growth in mature tropical forests are needed to evaluate the functional impact of lianas and their potential to affect the ability of tropical forests to sequester carbon, but these are currently lacking. Using data collected on tree growth rates, local growing conditions and liana competition in five permanent sampling plots in Amazonian Peru, we present the first ecosystem-level estimates of the effect of lianas on above-ground productivity of trees. By first constructing a multi-level linear mixed effect model to predict individual-tree diameter growth model using individual-tree growth conditions, we were able to then estimate stand-level above-ground biomass (AGB increment in the absence of lianas. We show that lianas, mainly by competing above-ground with trees, reduce tree annual above-ground stand-level biomass increment by ~10%, equivalent to 0.51 Mg dry weight ha−1 yr−1 or 0.25 Mg C ha−1 yr−1. AGB increment of lianas themselves was estimated to be 0.15 Mg dry weight ha−1 yr−1 or 0.07 Mg C ha−1 yr−1, thus only compensating ~29% of the liana-induced reduction in ecosystem AGB increment. Increasing liana pressure on tropical forests will therefore not only tend to reduce their carbon storage capacity, by indirectly promoting tree species with low-density wood, but also their rate of carbon uptake, with potential consequences for the rate of increase in atmospheric carbon dioxide.

  8. Tree growth and recruitment in a leveed floodplain forest in the Mississippi River Alluvial Valley, USA

    Science.gov (United States)

    Gee, Hugo K.W.; King, Sammy L.; Keim, Richard F.

    2014-01-01

    Flooding is a defining disturbance in floodplain forests affecting seed germination, seedling establishment, and tree growth. Globally, flood control, including artificial levees, dams, and channelization has altered flood regimes in floodplains. However, a paucity of data are available in regards to the long-term effects of levees on stand establishment and tree growth in floodplain forests. In this study, we used dendrochronological techniques to reconstruct tree recruitment and tree growth over a 90-year period at three stands within a ring levee in the Mississippi River Alluvial Valley (MAV) and to evaluate whether recruitment patterns and tree growth changed following levee construction. We hypothesized that: (1) sugarberry is increasing in dominance and overcup oak (Quercus lyrata) is becoming less dominant since the levee, and that changes in hydrology are playing a greater role than canopy disturbance in these changes in species dominance; and (2) that overcup oak growth has declined following construction of the levee and cessation of overbank flooding whereas that of sugarberry has increased. Recruitment patterns shifted from flood-tolerant overcup oak to flood-intolerant sugarberry (Celtis laevigata) after levee construction. None of the 122 sugarberry trees cored in this study established prior to the levee, but it was the most common species established after the levee. The mechanisms behind the compositional change are unknown, however, the cosmopolitan distribution of overcup oak during the pre-levee period and sugarberry during the post-levee period, the lack of sugarberry establishment in the pre-levee period, and the confinement of overcup oak regeneration to the lowest areas in each stand after harvest in the post-levee period indicate that species-specific responses to flooding and light availability are forcing recruitment patterns. Overcup oak growth was also affected by levee construction, but in contrast to our hypothesis, growth actually

  9. Nutrient foraging strategies are associated with productivity and population growth in forest shrubs.

    Science.gov (United States)

    Caplan, Joshua S; Stone, Bram W G; Faillace, Cara A; Lafond, Jonathan J; Baumgarten, Joni M; Mozdzer, Thomas J; Dighton, John; Meiners, Scott J; Grabosky, Jason C; Ehrenfeld, Joan G

    2017-04-01

    Temperate deciduous forest understoreys are experiencing widespread changes in community composition, concurrent with increases in rates of nitrogen supply. These shifts in plant abundance may be driven by interspecific differences in nutrient foraging (i.e. conservative vs. acquisitive strategies) and, thus, adaptation to contemporary nutrient loading conditions. This study sought to determine if interspecific differences in nutrient foraging could help explain patterns of shrub success and decline in eastern North American forests. Using plants grown in a common garden, fine root traits associated with nutrient foraging were measured for six shrub species. Traits included the mean and skewness of the root diameter distribution, specific root length (SRL), C:N ratio, root tissue density, arbuscular mycorrhizal colonization and foraging precision. Above- and below-ground productivity were also determined for the same plants, and population growth rates were estimated using data from a long-term study of community dynamics. Root traits were compared among species and associations among root traits, measures of productivity and rates of population growth were evaluated. Species fell into groups having thick or thin root forms, which correspond to conservative vs. acquisitive nutrient foraging strategies. Interspecific variation in root morphology and tissue construction correlated with measures of productivity and rates of cover expansion. Of the four species with acquisitive traits, three were introduced species that have become invasive in recent decades, and the fourth was a weedy native. In contrast, the two species with conservative traits were historically dominant shrubs that have declined in abundance in eastern North American forests. In forest understoreys of eastern North America, elevated nutrient availability may impose a filter on species success in addition to above-ground processes such as herbivory and overstorey canopy conditions. Shrubs that have

  10. Simulating the Effects of Fire on Forests in the Russian Far East: Integrating a Fire Danger Model and the FAREAST Forest Growth Model Across a Complex Landscape

    Science.gov (United States)

    Sherman, N. J.; Loboda, T.; Sun, G.; Shugart, H. H.; Csiszar, I.

    2008-12-01

    The remaining natural habitat of the critically endangered Amur tiger (Panthera tigris altaica) and Amur leopard (Panthera pardus orientalis) is a vast, biologically and topographically diverse area in the Russian Far East (RFE). Although wildland fire is a natural component of ecosystem functioning in the RFE, severe or repeated fires frequently re-set the process of forest succession, which may take centuries to return the affected forests to the pre-fire state and thus significantly alters habitat quality and long-term availability. The frequency of severe fire events has increased over the last 25 years, leading to irreversible modifications of some parts of the species' habitats. Moreover, fire regimes are expected to continue to change toward more frequent and severe events under the influence of climate change. Here we present an approach to developing capabilities for a comprehensive assessment of potential Amur tiger and leopard habitat availability throughout the 21st century by integrating regionally parameterized fire danger and forest growth models. The FAREAST model is an individual, gap-based model that simulates forest growth in a single location and demonstrates temporally explicit forest succession leading to mature forests. Including spatially explicit information on probabilities of fire occurrence at 1 km resolution developed from the regionally specific remotely -sensed data-driven fire danger model improves our ability to provide realistic long-term projections of potential forest composition in the RFE. This work presents the first attempt to merge the FAREAST model with a fire disturbance model, to validate its outputs across a large region, and to compare it to remotely-sensed data products as well as in situ assessments of forest structure. We ran the FAREAST model at 1,000 randomly selected points within forested areas in the RFE. At each point, the model was calibrated for temperature, precipitation, slope, elevation, and fire

  11. Growth rate of Heterobasidion annosum in Picea abies established on forest land and arable land

    Energy Technology Data Exchange (ETDEWEB)

    Bendz-Hellgren, M.; Johansson, Martin; Swedjemark, G.; Stenlid, J. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology; Brandtberg, P.O. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Ecology and Environmental Research

    1999-07-01

    The growth rates of Heterobasidion annosum in Norway spruce were investigated in southern Sweden. In one study, stump and tree roots in stands established on previous forest or arable land were inoculated with H. annosum-infested sawdust. After 1-3 yrs, the linear extent of colonization by the fungus was measured, based on detection of its conidiophores on incubated samples. The average growth rate was 25 cm yr{sup -1} in stump roots and 9 cm yr{sup -1} in tree roots, neither of which differed significantly between forest and arable land. The feeling of a decayed tree could enhance the spread of H. annosum within root systems. In the second study, the height of discoloration and extent of colonization by H. annosum, measured as above, were assessed in naturally infected trees. On average, discoloration moved through the roots and stem at a rate of 36 cm yr{sup -1}. Heterobasidion annosum was found 60 cm in advance of the discoloration, corresponding to a growth rate of 52 cm yr{sup -1}.

  12. Floristic conservation value, nested understory floras, and the development of second-growth forest.

    Science.gov (United States)

    Spyreas, Greg; Matthews, Jeffrey W

    2006-08-01

    Nestedness analysis can reveal patterns of plant composition and diversity among forest patches. For nested floral assemblages, the plants occupying any one patch are a nested subset of the plants present in successively more speciose patches. Elimination of sensitive understory plants with human disturbance is one of several mechanisms hypothesized to generate nonrandom, nested floral distributions. Hypotheses explaining distributions of understory plants remain unsubstantiated across broad landscapes of varying forest types and disturbance histories. We sampled the vegetation of 51 floodplain and 55 upland forests across Illinois (USA) to examine how the diversity, composition, and nestedness of understory floras related to their overstory growth and structure (basal area), and their overall floristic conservation value (mean C). We found that plant assemblages were nested with respect to site species richness, such that rare plants indicated diverse forests. Floras were also nested with respect to site mean C and basal area (BA). However, in an opposite pattern from what we had expected, floras of high-BA stands were nested subsets of those of low-BA stands. A set of early-successional plants restricted to low-BA stands, and more importantly, the absence of a set of true forest plants in high-BA stands, accounted for this pattern. Additionally, we observed a decrease in species richness with increasing BA. These results are consistent with the hypothesis that recovery of true forest plants does not occur concurrently with overstory regeneration following massive anthropogenic disturbance. Nestedness by site mean C indicates that high conservation value (conservative) plants co-occur in highly diverse stands; these forests are assumed to be less disturbed historically. Because site mean C was uncorrelated with BA, BA-neutral disturbances such as livestock usage are suggested as accounting for between-site differences in mean C. When considered individually

  13. Discrimination between acute and chronic decline of Central European forests using map algebra of the growth condition and forest biomass fuzzy sets: A case study.

    Science.gov (United States)

    Samec, Pavel; Caha, Jan; Zapletal, Miloš; Tuček, Pavel; Cudlín, Pavel; Kučera, Miloš

    2017-12-01

    Forest decline is either caused by damage or else by vulnerability due to unfavourable growth conditions or due to unnatural silvicultural systems. Here, we assess forest decline in the Czech Republic (Central Europe) using fuzzy functions, fuzzy sets and fuzzy rating of ecosystem properties over a 1×1km grid. The model was divided into fuzzy functions of the abiotic predictors of growth conditions (F pred including temperature, precipitation, acid deposition, soil data and relative site insolation) and forest biomass receptors (F rec including remote sensing data, density and volume of aboveground biomass, and surface humus chemical data). Fuzzy functions were designed at the limits of unfavourable, undetermined or favourable effects on the forest ecosystem health status. Fuzzy sets were distinguished through similarity in a particular membership of the properties at the limits of the forest status margins. Fuzzy rating was obtained from the least difference of F pred -F rec . Unfavourable F pred within unfavourable F rec indicated chronic damage, favourable F pred within unfavourable F rec indicated acute damage, and unfavourable F pred within favourable F rec indicated vulnerability. The model in the 1×1km grid was validated through spatial intersection with a point field of uniform forest stands. Favourable status was characterised by soil base saturation (BS)>50%, BCC/Al>1, C org >1%, MgO>6g/kg, and nitrogen depositionfuzzy model used suggests that improvement in forest health will depend on decreasing environmental load and restoration concordance between growth conditions and tree species composition. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Long-term growth and succession in restored and natural mangrove forests in southwestern Florida

    Science.gov (United States)

    Proffitt, C.E.; Devlin, D.J.

    2005-01-01

    We compared colonization, growth and succession from 1989 to 2000 in a restored mangrove site and in gap and closed canopy sites in a natural mangrove forest. The restored site was created in 1982 and planted with Rhizophora mangle (???2 m-2) propagules. By 1989, Laguncularia racemosa, with densities up to 12.9 tree m-2, was a dominant in all plots, although densities were greater at edge plots relative to inner plots, and near open water (west plots) relative to further inland (east plots), and in tall mangrove plots relative to scrub plots. Rhizophora mangle (1989 tree densities about 2 m-2) was a codominant in inner and scrub plots, while Avicennia germinans had the lowest densities (mangle and L. racemosa, rapid growth in height of all species (1989-1996), followed by a dieoff of L. racemosa in later years (1997-2000) as the canopy came to resemble that of tall mangrove plots. Colonization and growth rates were lower in gap and closed canopy regions of the natural forest relative to rates in the restored site. After 11 years, densities of L. racemosa were 10-20x lower and R. mangle slightly less in the gap relative to densities in tall mangrove plots in the restored site at the same age. Although the restored stand had converged with the natural forest by 2000 in terms of some factors such as species richness, vegetation cover, litterfall, and light penetration, trees were still much smaller and stem densities much higher. Full development of mature structure and ecological function will likely require decades more development. ?? Springer 2005.

  15. Earthworm influence on N availability and the growth of Cecropia schreberiana in tropical pasture and forest soils

    Science.gov (United States)

    G. Gonzalez; X. Zou

    1999-01-01

    This greenhouse study examines the effects of Pontoscolex corethrurus on the growth of Cecropia scheberiana in forest and pasture soils. Four treatments (0, 2, 20 worms and 0 worms + urea fertilizer) were applied to the soils to test if earthworms affect nitrogen availability, and consequently the growth of C. scheberiana. We recorded the number of seedlings, leaves,...

  16. Assessing climate change effects on long-term forest development: adjusting growth, phenology, and seed production in a gap model

    NARCIS (Netherlands)

    Meer, van der P.J.; Jorritsma, I.T.M.; Kramer, K.

    2002-01-01

    The sensitivity of forest development to climate change is assessed using a gap model. Process descriptions in the gap model of growth, phenology, and seed production were adjusted for climate change effects using a detailed process-based growth modeland a regression analysis. Simulation runs over

  17. Reconstructed old-growth forest stand structure and composition of two stands on the Olympic Peninsula, Washington state

    Science.gov (United States)

    David H. Peter; Constance A. Harrington

    2010-01-01

    We reconstructed the stand structure and composition for two western Washington old-growth forest stands harvested around 1930 (named Fresca and Rail) from field and historical data. Both old-growth stands had a codominant or dominant 250-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) overstory with a few scattered older Douglas-fir....

  18. 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

  19. Preliminary Survey on TRY Forest Traits and Growth Index Relations - New Challenges

    Science.gov (United States)

    Lyubenova, Mariyana; Kattge, Jens; van Bodegom, Peter; Chikalanov, Alexandre; Popova, Silvia; Zlateva, Plamena; Peteva, Simona

    2016-04-01

    Forest ecosystems provide critical ecosystem goods and services, including food, fodder, water, shelter, nutrient cycling, and cultural and recreational value. Forests also store carbon, provide habitat for a wide range of species and help alleviate land degradation and desertification. Thus they have a potentially significant role to play in climate change adaptation planning through maintaining ecosystem services and providing livelihood options. Therefore the study of forest traits is such an important issue not just for individual countries but for the planet as a whole. We need to know what functional relations between forest traits exactly can express TRY data base and haw it will be significant for the global modeling and IPBES. The study of the biodiversity characteristics at all levels and functional links between them is extremely important for the selection of key indicators for assessing biodiversity and ecosystem services for sustainable natural capital control. By comparing the available information in tree data bases: TRY, ITR (International Tree Ring) and SP-PAM the 42 tree species are selected for the traits analyses. The dependence between location characteristics (latitude, longitude, altitude, annual precipitation, annual temperature and soil type) and forest traits (specific leaf area, leaf weight ratio, wood density and growth index) is studied by by multiply regression analyses (RDA) using the statistical software package Canoco 4.5. The Pearson correlation coefficient (measure of linear correlation), Kendal rank correlation coefficient (non parametric measure of statistical dependence) and Spearman correlation coefficient (monotonic function relationship between two variables) are calculated for each pair of variables (indexes) and species. After analysis of above mentioned correlation coefficients the dimensional linear regression models, multidimensional linear and nonlinear regression models and multidimensional neural networks models are

  20. Private forests, housing growth, and America’s water supply: A report from the Forests on the Edge and Forests to Faucets Projects

    Science.gov (United States)

    M. H. Mockrin; R. L. Lilja; E. Weidner; S. M. Stein; M. A. Carr

    2014-01-01

    America’s private forests provide a vast array of public goods and services, including abundant, clean surface water. Forest loss and development can affect water quality and quantity when forests are removed and impervious surfaces, such as paved roads, spread across the landscape. We rank watersheds across the conterminous United States according to the contributions...

  1. Early subtropical forest growth is driven by community mean trait values and functional diversity rather than the abiotic environment

    OpenAIRE

    Kröber, Wenzel; Li, Ying; Härdtle, Werner; Ma, Keping; Schmid, Bernhard; Schmidt, Karsten; Scholten, Thomas; Seidler, Gunnar; von Oheimb, Goddert; Welk, Erik; Wirth, Christian; Bruelheide, Helge

    2015-01-01

    While functional diversity (FD) has been shown to be positively related to a number of ecosystem functions including biomass production, it may have a much less pronounced effect than that of environmental factors or species specific properties. Leaf and wood traits can be considered particularly relevant to tree growth, as they reflect a trade-off between resources invested into growth and persistence. Our study focussed on the degree to which early forest growth was driven by FD, the envir...

  2. Epiphytic and endophytic bacteria that promote growth of ethnomedicinal plants in the subtropical forests of Meghalaya, India

    OpenAIRE

    Fenella Mary War Nongkhlaw; S. R. Joshi

    2014-01-01

    The present study was aimed to investigate the endophytic and epiphytic bacteria associated with selected ethnomedicinal plants from the pristine subtropical forests of Meghalaya and analyse them for plant growth promotion and antagonistic ability. This study is an attempt to explore plant associated bacteria which are beneficial to host plants, and thus aid in the conservation of ethnomedicinal plants of the studied subtropical forests, which are dwindling due to exploitation. The plant grow...

  3. Water-use efficiency of an old-growth forest in lower subtropical China.

    Science.gov (United States)

    Liu, Xiaodong; Chen, Xiuzhi; Li, Ronghua; Long, Fengling; Zhang, Lu; Zhang, Qianmei; Li, Jiyue

    2017-02-21

    Carbon and water fluxes are key properties of ecosystem processes and functions. A better understanding of their temporal dynamics and coupling mechanism between these fluxes will help us improve ecosystem management for mitigation as well as adaption to future climatic change. From 2003 to 2009, carbon and water flux data were obtained by the eddy covariance method over an old-growth forest in the lower subtropical China. The 7 years of observational data indicated that the water-use efficiency (WUE) of the old-growth forest exhibited weak inter-annual variability. The mean annual WUE ranged from 1.70 to 1.98 g C kg -1 H 2 O. An analysis of the effects of environmental variables on the monthly gross primary productivity (GPP) and evapotranspiration (ET) indicated that solar radiation, air temperature, precipitation and vapor pressure deficit (VPD) produced similar effects on the monthly GPP and ET, which suggests that photosynthesis and ET were similarly driven by the climatic variables. At the monthly scale, the WUE decreased significantly as the precipitation and soil moisture content increased. However, a significant correlation was not detected between the WUE and the VPD at the monthly scale. Moisture conditions tend to be major drivers of the ecosystem WUE.

  4. Seedling growth in greenhouse conditions of the forest species Dialium guianense (Aubl. Sandwith

    Directory of Open Access Journals (Sweden)

    Georgina Vargas Simon

    2018-01-01

    Full Text Available Dialium guianense is used for its wood and fruit production, and is a tropical tree species native to evergreen forests. Given the threat these forests face, the purpose of this work was to evaluate the initial growth of the plant under greenhouse conditions, for aiming in the development of propagation programs. Seedlings of the species were transplanted to nursery bags under a completely randomized design and grown for 10 months with an initial population of 200 plants. At the end of the experiment, the shoot and root reached lengths of 32.8 and 28.9 cm, respectively. The average number of composite leaves was 12.3 each with seven leaflets. The average biomass was 2.5 g for the shoot, 1.6 g for roots, and 3.7 g for leaves, with a shoot/root around four. The average relative growth rate (RGR was 15 mg g-1 day-. These characteristics indicate that D. guianense is a late successional species.

  5. Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica.

    Science.gov (United States)

    Seas-Carvajal, Carolina; Avalos, Gerardo

    2013-06-01

    Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought following eight different transects distributed evenly in old-growth and secondary forests across four different soil types, covering an area of 9 420m2. We found fungi in four different substrates: litter, fallen branches, dead trunks, and roots, for a total of 61 samples. Correspondence analysis showed that the occurrence of fungi and soil types were related (inertia = 0.21, p = 0.071). We found a significant relationship between the presence of fungi and the distribution of soil types (X2 = 18.89, df = 9, p = 0.026). We found only three samples with fruiting bodies, two of which had Mycena and the other had one fungus of the order Xylariales (possibly Hypoxylon sp., Kretzschmariella sp., Xylaria sp.). Future work will concentrate on exploring other aspects of their ecology, such as their dispersal and substrate preference. This information will facilitate field identification and will foster more research on the distribution, seasonality, reproductive phenology and ecological requirements of this group of Fungi.

  6. Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica

    Directory of Open Access Journals (Sweden)

    Carolina Seas-Carvajal

    2013-06-01

    Full Text Available Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought following eight different transects distributed evenly in old-growth and secondary forests across four different soil types, covering an area of 9 420m². We found fungi in four different substrates: litter, fallen branches, dead trunks, and roots, for a total of 61 samples. Correspondence analysis showed that the occurrence of fungi and soil types were related (inertia=0.21, p=0.071. We found a significant relationship between the presence of fungi and the distribution of soil types (X²=18.89, df=9, p=0.026. We found only three samples with fruiting bodies, two of which had Mycena and the other had one fungus of the order Xylariales (possibly Hypoxylon sp., Kretzschmariella sp., Xylaria sp.. Future work will concentrate on exploring other aspects of their ecology, such as their dispersal and substrate preference. This information will facilitate field identification and will foster more research on the distribution, seasonality, reproductive phenology and ecological requirements of this group of Fungi.

  7. Growth duration is a better predictor of stem increment than carbon supply in a Mediterranean oak forest: implications for assessing forest productivity under climate change.

    Science.gov (United States)

    Lempereur, Morine; Martin-StPaul, Nicolas K; Damesin, Claire; Joffre, Richard; Ourcival, Jean-Marc; Rocheteau, Alain; Rambal, Serge

    2015-08-01

    Understanding whether tree growth is limited by carbon gain (source limitation) or by the direct effect of environmental factors such as water deficit or temperature (sink limitation) is crucial for improving projections of the effects of climate change on forest productivity. We studied the relationships between tree basal area (BA) variations, eddy covariance carbon fluxes, predawn water potential (Ψpd ) and temperature at different timescales using an 8-yr dataset and a rainfall exclusion experiment in a Quercus ilex Mediterranean coppice. At the daily timescale, during periods of low temperature (forest productivity under climate change scenarios. © 2015 CNRS-ADEME New Phytologist © 2015 New Phytologist Trust.

  8. Accelerating Forest Growth Enhancement due to Climate and Atmospheric Changes in British Colombia, Canada over 1956-2001

    Science.gov (United States)

    Wu, Chaoyang; Hember, Robbie A.; Chen, Jing M.; Kurz, Werner A.; Price, David T.; Boisvenue, Céline; Gonsamo, Alemu; Ju, Weimin

    2014-03-01

    Changes in climate and atmospheric CO2 and nitrogen (N) over the last several decades have induced significant effects on forest carbon (C) cycling. However, contributions of individual factors are largely unknown because of the lack of long observational data and the undifferentiating between intrinsic factors and external forces in current ecosystem models. Using over four decades (1956-2001) of forest inventory data at 3432 permanent samples in maritime and boreal regions of British Columbia (B.C.), Canada, growth enhancements were reconstructed and partitioned into contributions of climate, CO2 and N after removal of age effects. We found that climate change contributed a particularly large amount (over 70%) of the accumulated growth enhancement, while the remaining was attributed to CO2 and N, respectively. We suggest that climate warming is contributing a widespread growth enhancement in B.C.'s forests, but ecosystem models should consider CO2 and N fertilization effects to fully explain inventory-based observations.

  9. Carbon sequestration potential of second-growth forest regeneration in the Latin American tropics

    NARCIS (Netherlands)

    Chazdon, R.L.; Broadbent, E.N.; Rozendaal, Danae; Bongers, F.; Jakovac, A.C.; Braga Junqueira, A.; Lohbeck, M.W.M.; Pena Claros, M.; Poorter, L.

    2016-01-01

    Regrowth of tropical secondary forests following complete or nearly complete removal of forest vegetation actively stores carbon in aboveground biomass, partially counterbalancing carbon emissions from deforestation, forest degradation, burning of fossil fuels, and other anthropogenic sources. We

  10. Quantifying the direct effects of SO2 and O3 on forest growth

    International Nuclear Information System (INIS)

    Mohren, G.M.J.; Jorritsma, I.T.M.; Vermetten, A.W.M.; Kropff, M.J.; Smeets, W.L.M.; Tiktak, A.

    1992-01-01

    The direct effects of sulphur dioxide (SO 2 ) and ozone (O 3 ) on the growth of two Douglas-fir stands are quantified from continuous measurements of the concentration of air pollution above the canopy combined with a quantitative description of the direct effects of gaseous uptake of pollutants on photosynthesis and respiration. Effects at the leaf level are scaled up to the stand level, using a deterministic model of forest growth that uses time steps of 1 day. This approach enables total uptake of gaseous air pollutants and their effects on canopy assimilation and growth to be quantified, taking ambient weather conditions and stand structure into account. By using a description of water balance in the model, the influence of limitations in oil moisture availability can also be incorporated, and the combined effects of air pollution and water shortage can be accounted for. Under Dutch conditions, with average daily concentrations of 10 μg m -1 for SO 2 and 50 μg m -3 for O 3 , the short-term effects on tree growth appear to be minor, except near local sources, and during episodes of high concentrations under stable weather conditions. The possible magnitude of long-term effects of exposure to O 3 is assessed using a hypothetical relationship between dose (exposure multiplied by duration) and foliage loss. From this it is concluded that long-term effects may be significant in stands with a low leaf area index

  11. Abiotic and Biotic Soil Characteristics in Old Growth Forests and Thinned or Unthinned Mature Stands in Three Regions of Oregon

    Directory of Open Access Journals (Sweden)

    David A. Perry

    2012-09-01

    Full Text Available We compared forest floor depth, soil organic matter, soil moisture, anaerobic mineralizable nitrogen (a measure of microbial biomass, denitrification potential, and soil/litter arthropod communities among old growth, unthinned mature stands, and thinned mature stands at nine sites (each with all three stand types distributed among three regions of Oregon. Mineral soil measurements were restricted to the top 10 cm. Data were analyzed with both multivariate and univariate analyses of variance. Multivariate analyses were conducted with and without soil mesofauna or forest floor mesofauna, as data for those taxa were not collected on some sites. In multivariate analysis with soil mesofauna, the model giving the strongest separation among stand types (P = 0.019 included abundance and richness of soil mesofauna and anaerobic mineralizable nitrogen. The best model with forest floor mesofauna (P = 0.010 included anaerobic mineralizable nitrogen, soil moisture content, and richness of forest floor mesofauna. Old growth had the highest mean values for all variables, and in both models differed significantly from mature stands, while the latter did not differ. Old growth also averaged higher percent soil organic matter, and analysis including that variable was significant but not as strong as without it. Results of the multivariate analyses were mostly supported by univariate analyses, but there were some differences. In univariate analysis, the difference in percent soil organic matter between old growth and thinned mature was due to a single site in which the old growth had exceptionally high soil organic matter; without that site, percent soil organic matter did not differ between old growth and thinned mature, and a multivariate model containing soil organic matter was not statistically significant. In univariate analyses soil mesofauna had to be compared nonparametrically (because of heavy left-tails and differed only in the Siskiyou Mountains, where

  12. Effects of soil fertility and topography on tree growth in subtropical forest ecosystems

    Science.gov (United States)

    Seitz, Steffen; Goebes, Philipp; Kühn, Peter; Schmidt, Karsten; Song, Zhengshan; Scholten, Thomas

    2016-04-01

    This study investigates the effects of soil fertility and topography on tree growth in a forest biodiversity and ecosystem functioning experiment. The main objective was to examine whether topography controls small-scale differences of soil fertility expressed in soil texture, soil pH, soil organic carbon (SOC), N, cation exchange capacity (CEC), base saturation, Na, K, Mg, Ca, Fe and Mn in a hilly forest area in subtropical China. Geomorphometric terrain analyses were carried out at a spatial resolution of 5 m × 5 m. Soil samples of different depth increments and data on tree growth were collected from a total of 566 plots (667 m2 each). All plots were classified into geomorphological units. Analyses of variance and linear regressions were applied to all terrain, soil fertility and tree growth attributes. In general, limited soil formation and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment. This explains the concurrently increasing CEC and SOC stocks downslope, in hollows and in valleys. However, colluvial carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways. The results showed that soil fertility is mainly influenced by topography. Monte-Carlo flow accumulation (MCCA), curvature, slope and aspect significantly affected soil fertility. Furthermore, soil fertility attributes were affected by the different geomorphological positions of the experimental sites with ridge and spur positions showing lower exchangeable base cation contents due to leaching. This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth. Few soil fertility attributes affect tree height after 1-2 years of growth, among which C stocks proved to be most important while pHKCl and CEC only played minor

  13. Do rising temperatures always increase forest productivity? Interacting effects of temperature, precipitation, cloudiness and soil texture on tree species growth and competition

    Science.gov (United States)

    Eric J. Gustafson; Brian R. Miranda; Arjan M.G. De Bruijn; Brian R. Sturtevant; Mark E. Kubiske

    2017-01-01

    Forest landscape models (FLM) are increasingly used to project the effects of climate change on forested landscapes, yet most use phenomenological approaches with untested assumptions about future forest dynamics. We used a FLM that relies on first principles to mechanistically simulate growth (LANDIS-II with PnET-Succession) to systematically explore how landscapes...

  14. The Effect of Herbivory by White-Tailed Deer and Additionally Swamp Rabbits in an Old-Growth Bottomland Hardwood Forest

    Science.gov (United States)

    Margaret S. Devall; Bernard R. Parresol; Winston P. Smith

    2001-01-01

    Forest openings create internal patchiness and offer different habitat qualities that attract wildlife, especially herbivores, that flourish along forest edges. But intense herbivory in these openings can reduce or eliminate herbaceous and woody species and thus influence local species composition and structure of the forest. This study in an old-growth bottomland...

  15. Effects of tropical montane forest disturbance on epiphytic macrolichens

    Energy Technology Data Exchange (ETDEWEB)

    Benitez, Angel [Instituto de Ecologia, Herbario HUTPL, Universidad Tecnica Particular de Loja, San Cayetano s/n, Loja (Ecuador); Prieto, Maria, E-mail: maria.prieto@urjc.es [Area de Biodiversidad y Conservacion, ESCET, Universidad Rey Juan Carlos, Mostoles, E-28933, Madrid (Spain); Gonzalez, Yadira [Instituto de Ecologia, Herbario HUTPL, Universidad Tecnica Particular de Loja, San Cayetano s/n, Loja (Ecuador); Aragon, Gregorio [Area de Biodiversidad y Conservacion, ESCET, Universidad Rey Juan Carlos, Mostoles, E-28933, Madrid (Spain)

    2012-12-15

    The high diversity of epiphytes typical of undisturbed montane tropical forests has been negatively affected by continuous deforestation and forest conversion to secondary vegetation. Macrolichens are an important component of these epiphytes. Because their physiology is strongly coupled to humidity and solar radiation, we hypothesized that microclimatic changes derived from forest clearing and logging can affect the diversity of these poikilohydric organisms. In southern Ecuador, we examined three types of forests according to a disturbance gradient (primary forests, secondary forests, and monospecific forests of Alnus acuminata) for the presence/absence and coverage of epiphytic macrolichens that we identified on 240 trees. We found that total richness tended to decrease when the range of the disturbance increased. The impoverishment was particularly drastic for 'shade-adapted lichens', while the richness of 'heliophytic lichens' increased in the drier conditions of secondary growth. Epiphytic composition also differed significantly among the three types of forests, and the similarity decreased when the range of the disturbance was greater. We concluded that a span of 40 years of recovery by secondary vegetation was not enough to regenerate the diversity of epiphytic macrolichens that was lost due to forest disturbances. -- Highlights: Black-Right-Pointing-Pointer Tropical montane forest disturbance drastically reduced macrolichen diversity. Black-Right-Pointing-Pointer Species loss was most severe for the 'shade-adapted lichens' because high radiation is harmful to them. Black-Right-Pointing-Pointer In secondary forests lichen diversity of native forests was not regenerated. Black-Right-Pointing-Pointer The protection of remnants of primary tropical forest might help to preserve a diverse community of epiphytic macrolichens.

  16. Low-temperature catalyst activator: mechanism of dense carbon nanotube forest growth studied using synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Akito Takashima

    2014-07-01

    Full Text Available The mechanism of the one-order-of-magnitude increase in the density of vertically aligned carbon nanotubes (CNTs achieved by a recently developed thermal chemical vapor deposition process was studied using synchrotron radiation spectroscopic techniques. In the developed process, a Ti film is used as the underlayer for an Fe catalyst film. A characteristic point of this process is that C2H2 feeding for the catalyst starts at a low temperature of 450°C, whereas conventional feeding temperatures are ∼800°C. Photoemission spectroscopy using soft and hard X-rays revealed that the Ti underlayer reduced the initially oxidized Fe layer at 450°C. A photoemission intensity analysis also suggested that the oxidized Ti layer at 450°C behaved as a support for nanoparticle formation of the reduced Fe, which is required for dense CNT growth. In fact, a CNT growth experiment, where the catalyst chemical state was monitored in situ by X-ray absorption spectroscopy, showed that the reduced Fe yielded a CNT forest at 450°C. Contrarily, an Fe layer without the Ti underlayer did not yield such a CNT forest at 450°C. Photoemission electron microscopy showed that catalyst annealing at the conventional feeding temperature of 800°C caused excess catalyst agglomeration, which should lead to sparse CNTs. In conclusion, in the developed growth process, the low-temperature catalyst activation by the Ti underlayer before the excess Fe agglomeration realised the CNT densification.

  17. Dynamic anthropogenic edge effects on the distribution and diversity of fungi in fragmented old-growth forests.

    Science.gov (United States)

    Ruete, Alejandro; Snäll, Tord; Jönsson, Mari

    2016-07-01

    Diversity patterns and dynamics at forest edges are not well understood. We disentangle the relative importance of edge-effect variables on spatio-temporal patterns in species richness and occupancy of deadwood-dwelling fungi in fragmented old-growth forests. We related richness and log occupancy by 10 old-growth forest indicator fungi and by two common fungi to log conditions in natural and anthropogenic edge habitats of 31 old-growth Picea abies forest stands in central Sweden. We compared edge-to-interior gradients (100 m) to the forest interior (beyond 100 m), and we analyzed stand-level changes after 10 yr. Both richness and occupancy of logs by indicator species was negatively related to adjacent young clear-cut edges, but this effect decreased with increasing clear-cut age. The occupancy of logs by indicator species also increased with increasing distance to the natural edges. In contrast, the occupancy of logs by common species was positively related or unrelated to distance to clear-cut edges regardless of the edge age, and this was partly explained by fungal specificity to substrate quality. Stand-level mean richness and mean occupancy of logs did not change for indicator or common species over a decade. By illustrating the importance of spatial and temporal dimensions of edge effects, we extend the general understanding of the distribution and diversity of substrate-confined fungi in fragmented old-growth forests. Our results highlight the importance of longer forest rotation times adjacent to small protected areas and forest set-asides, where it may take more than 50 yr for indicator species richness levels to recover to occupancy levels observed in the forest interior. Also, non-simultaneous clear-cutting of surrounding productive forests in a way that reduces the edge effect over time (i.e., dynamic buffers) may increase the effective core area of small forest set-asides and improve their performance on protecting species of special concern for

  18. Assessing the effects of management on forest growth across France: insights from a new functional-structural model.

    Science.gov (United States)

    Guillemot, Joannès; Delpierre, Nicolas; Vallet, Patrick; François, Christophe; Martin-StPaul, Nicolas K; Soudani, Kamel; Nicolas, Manuel; Badeau, Vincent; Dufrêne, Eric

    2014-09-01

    The structure of a forest stand, i.e. the distribution of tree size features, has strong effects on its functioning. The management of the structure is therefore an important tool in mitigating the impact of predicted changes in climate on forests, especially with respect to drought. Here, a new functional-structural model is presented and is used to assess the effects of management on forest functioning at a national scale. The stand process-based model (PBM) CASTANEA was coupled to a stand structure module (SSM) based on empirical tree-to-tree competition rules. The calibration of the SSM was based on a thorough analysis of intersite and interannual variability of competition asymmetry. The coupled CASTANEA-SSM model was evaluated across France using forest inventory data, and used to compare the effect of contrasted silvicultural practices on simulated stand carbon fluxes and growth. The asymmetry of competition varied consistently with stand productivity at both spatial and temporal scales. The modelling of the competition rules enabled efficient prediction of changes in stand structure within the CASTANEA PBM. The coupled model predicted an increase in net primary productivity (NPP) with management intensity, resulting in higher growth. This positive effect of management was found to vary at a national scale across France: the highest increases in NPP were attained in forests facing moderate to high water stress; however, the absolute effect of management on simulated stand growth remained moderate to low because stand thinning involved changes in carbon allocation at the tree scale. This modelling approach helps to identify the areas where management efforts should be concentrated in order to mitigate near-future drought impact on national forest productivity. Around a quarter of the French temperate oak and beech forests are currently in zones of high vulnerability, where management could thus mitigate the influence of climate change on forest yield.

  19. Spider (Arachnida, Araneae) diversity in secondary and old-growth southern Atlantic forests of Paraná state, Brazil.

    Science.gov (United States)

    Raub, Florian; Höfer, Hubert; Scheuermann, Ludger

    2017-07-01

    The data presented here have been collected in the southern part of the Atlantic Forest (Mata Atlântica) in the state of Paraná, Brazil within a bilateral scientific project (SOLOBIOMA). The project aimed to assess the quality of secondary forests of different regeneration stages in comparison with old-growth forests with regard to diversity of soil animals and related functions. The Atlantic Forest is a hotspot of biological diversity with an exceptionally high degree of endemic species, extending over a range of 3,500 km along the coast of Brazil. The anthropogenic pressure in the region is very high with three of the biggest cities of Brazil (São Paulo, Rio de Janeiro, and Curitiba) lying in its extension. An evaluation of the value of secondary forests for biodiversity conservation is becoming more and more important due to the complete disappearance of primary forests. In 2005, we sampled spiders in 12 sites of three successional stages (5-8, 10-15, 35-50 yr old, three replicates of each forest stage) and old-growth forests (> 100 yr untouched, also three replicates). All sites were inside a private nature reserve (Rio Cachoeira Nature Reserve). We repeated the sampling design and procedure in 2007 in a second private reserve (Itaqui Nature Reserve). The two nature reserves are within about 25 km of each other within a well preserved region of the Mata Atlântica, where the matrix of the landscape mosaic is still forest. A widely accepted standard protocol was used in a replicated sampling design to apply statistical analyses to the resulting data set and allow for comparison with other studies in Brazil. Spiders were sorted to family level and counted; the adult spiders further identified to species if possible or classified as morphospecies with the help of several spider specialists. © 2017 by the Ecological Society of America.

  20. Analyses of the impact of changes in atmospheric deposition and climate on forest growth in European monitoring plots: A stand growth approach

    NARCIS (Netherlands)

    Solberg, S.; Dobbertin, M.; Reinds, G.J.; Andreassen, K.; Lange, H.; Garcia Fernandez, P.; Hildingsson, A.; Vries, de W.

    2009-01-01

    During the last 15 years a number of studies have shown increasing forest growth in central Europe, rather than a decline as was expected due to negative effects of air pollution. We have here used data from intensive monitoring plots spread over Europe for a five year period in order to examine the

  1. Local population extinction and vitality of an epiphytic lichen in fragmented old-growth forest.

    Science.gov (United States)

    Ockinger, Erik; Nilsson, Sven G

    2010-07-01

    The population dynamics of organisms living in short-lived habitats will largely depend on the turnover of habitat patches. It has been suggested that epiphytes, whose host plants can be regarded as habitat patches, often form such patch-tracking populations. However, very little is known about the long-term fate of epiphyte individuals and populations. We estimated life span and assessed environmental factors influencing changes in vitality, fertility, abundance, and distribution of the epiphytic lichen species Lobaria pulmonaria on two spatial scales, individual trees and forest patches, over a period of approximately 10 years in 66 old-growth forest fragments. The lichen had gone extinct from 7 of the 66 sites (13.0%) where it was found 10 years earlier, even though the sites remained unchanged. The risk of local population extinction increased with decreasing population size. In contrast to the decrease in the number of occupied trees and sites, the mean area of the lichen per tree increased by 43.0%. The number of trees with fertile ramets of L. pulmonaria increased from 7 (approximately 1%) to 61 (approximately 10%) trees, and the number of forest fragments with fertile ramets increased from 4 to 23 fragments. The mean annual rate of L. pulmonaria extinction at the tree level was estimated to be 2.52%, translating into an expected lifetime of 39.7 years. This disappearance rate is higher than estimated mortality rates for potential host trees. The risk of extinction at the tree level was significantly positively related to tree circumference and differed between tree species. The probability of presence of fertile ramets increased significantly with local population size. Our results show a long expected lifetime of Lobaria pulmonaria ramets on individual trees and a recent increase in vitality, probably due to decreasing air pollution. The population is, however, declining slowly even though remaining stands are left uncut, which we interpret as an

  2. Space sequestration below ground in old-growth spruce-beech forests – signs for facilitation?

    Directory of Open Access Journals (Sweden)

    Andreas eBolte

    2013-08-01

    Full Text Available Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤ 2 mm by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1 spruce as a central tree, (2 spruce as competitor, (3 beech as a central tree, and (4 beech as competitor. Mean values of life fine root attributes like biomass (FRB, length (FRL, and root area index (RAI were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA, asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

  3. 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.

  4. 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

  5. Stimulating seedling growth in early stages of secondary forest succession: a modeling approach to guide tree liberation.

    Directory of Open Access Journals (Sweden)

    Marijke van Kuijk

    2014-07-01

    Full Text Available Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target trees by reducing competition for light with neighboring plants. However, liberation has not always the desired effect, likely due to differences in light requirement between tree species. Here we present a 3D-model, which calculates photosynthetic rate of individual trees in a vegetation stand. It enables us to examine how stature, crown structure and physiological traits of target trees and characteristics of the surrounding vegetation together determine effects of light on tree growth. The model was applied to a liberation experiment conducted with three pioneer species in a young secondary forest in Vietnam. Species responded differently to the treatment depending on their height, crown structure and their shade-tolerance level. Model simulations revealed practical thresholds over which the tree growth response is heavily influenced by the height and density of surrounding vegetation and gap radius. There were strong correlations between calculated photosynthetic rates and observed growth: the model was well able to predict growth of trees in young forests and the effects of liberation there upon. Thus our model serves as a useful tool to analyze light competition between young trees and surrounding vegetation and may help assess the potential effect of tree liberation.

  6. Stimulating seedling growth in early stages of secondary forest succession: a modeling approach to guide tree liberation.

    Science.gov (United States)

    van Kuijk, Marijke; Anten, Niels P R; Oomen, Roelof J; Schieving, Feike

    2014-01-01

    Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target trees by reducing competition for light with neighboring plants. However, liberation has not always had the desired effect, likely due to differences in light requirement between tree species. Here we present a 3D-model, which calculates photosynthetic rate of individual trees in a vegetation stand. It enables us to examine how stature, crown structure, and physiological traits of target trees and characteristics of the surrounding vegetation together determine effects of light on tree growth. The model was applied to a liberation experiment conducted with three pioneer species in a young secondary forest in Vietnam. Species responded differently to the treatment depending on their height, crown structure and their shade-tolerance level. Model simulations revealed practical thresholds over which the tree growth response is heavily influenced by the height and density of surrounding vegetation and gap radius. There were strong correlations between calculated photosynthetic rates and observed growth: the model was well able to predict growth of trees in young forests and the effects of liberation there upon. Thus, our model serves as a useful tool to analyze light competition between young trees and surrounding vegetation and may help assess the potential effect of tree liberation.

  7. The Validation of the Mixedwood Growth Model (MGM for Use in Forest Management Decision Making

    Directory of Open Access Journals (Sweden)

    Mike Bokalo

    2013-01-01

    Full Text Available We evaluated the Mixedwood Growth Model (MGM at a whole model scale for pure and mixed species stands of aspen and white spruce in the western boreal forest. MGM is an individual tree-based, distance-independent growth model, designed to evaluate growth and yield implications relating to the management of white spruce, black spruce, aspen, lodgepole pine, and mixedwood stands in Alberta, British Columbia, Saskatchewan, and Manitoba. Our validation compared stand-level model predictions against re-measured data (volume, basal area, diameter at breast height (DBH, average and top height and density from permanent sample plots using combined analysis of residual plots, bias statistics, efficiency and an innovative application of the equivalence test. For state variables, the model effectively simulated juvenile and mature stages of stand development for both pure and mixed species stands of aspen and white spruce in Alberta. MGM overestimates increment in older stands likely due to age-related pathology and weather-related stand damage. We identified underestimates of deciduous density and volume in Saskatchewan. MGM performs well for increment in postharvest stands less than 30 years of age. These results illustrate the comprehensive application of validation metrics to evaluate a complex model, and provide support for the use of MGM in management planning.

  8. An experimental test of the causes of forest growth decline with stand age.

    Science.gov (United States)

    Michael G. Ryan; Dan Binkley; James H. Fownes; Christian Giardina; Randy S. Senock

    2004-01-01

    The decline in aboveground wood production after canopy closure in even-aged forest stands is a common pattern in forests, but clear evidence for the mechanism causing the decline is lacking. The problem is fundamental to forest biology, commercial forestry (the decline sets the rotation age), and to carbon storage in forests. We tested three hypotheses...

  9. Simulating Urban Growth Using a Random Forest-Cellular Automata (RF-CA Model

    Directory of Open Access Journals (Sweden)

    Courage Kamusoko

    2015-04-01

    Full Text Available Sustainable urban planning and management require reliable land change models, which can be used to improve decision making. The objective of this study was to test a random forest-cellular automata (RF-CA model, which combines random forest (RF and cellular automata (CA models. The Kappa simulation (KSimulation, figure of merit, and components of agreement and disagreement statistics were used to validate the RF-CA model. Furthermore, the RF-CA model was compared with support vector machine cellular automata (SVM-CA and logistic regression cellular automata (LR-CA models. Results show that the RF-CA model outperformed the SVM-CA and LR-CA models. The RF-CA model had a Kappa simulation (KSimulation accuracy of 0.51 (with a figure of merit statistic of 47%, while SVM-CA and LR-CA models had a KSimulation accuracy of 0.39 and −0.22 (with figure of merit statistics of 39% and 6%, respectively. Generally, the RF-CA model was relatively accurate at allocating “non-built-up to built-up” changes as reflected by the correct “non-built-up to built-up” components of agreement of 15%. The performance of the RF-CA model was attributed to the relatively accurate RF transition potential maps. Therefore, this study highlights the potential of the RF-CA model for simulating urban growth.

  10. 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

  11. 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.

  12. Functional structure of ant and termite assemblages in old growth forest, logged forest and oil palm plantation in Malaysian Borneo

    OpenAIRE

    Luke, Sarah H.; Fayle, Tom M.; Eggleton, Paul; Turner, Edgar C.; Davies, Richard G.

    2014-01-01

    Forested tropical landscapes around the world are being extensively logged and converted to agriculture, with serious consequences for biodiversity and potentially ecosystem functioning. Here we investigate associations between habitat disturbance and functional diversity of ants and termites – two numerically dominant and functionally important taxa in tropical rain forests that perform key roles in predation, decomposition, nutrient cycling and seed dispersal. We compared ant and termite oc...

  13. Growth, purification and characterization of Semliki Forest virus in Ehrlich ascites tumor cell suspensions.

    Science.gov (United States)

    Ivanic, S

    1976-01-01

    The growth of Semliki Forest Virus (SFV) in suspension cultures of Ehrlich Ascites (EA) cells and its purification is described. Large volumes of virus material were concentrated by filtration with DIAFLO XM-300 membrane and precipitation with ammonium sulfate. A combination of protamine sulfate treatment, centrifugation of the virus onto a 50 per cent sucrose cushion, and sedimentation through a 5--30 per cent sucrose density gradient was employed. The purified virus particles were homogeneous as revealed by electron microscopy, by moving boundary electrophoresis, and by polyacrylamide gel electrophoresis. Virus suspensions containing 1 mg/ml of protein had a hemagglutinin titer of 1:12,000 when measured with 0.25 per cent goose red blood cells.

  14. 137Cs distribution in the wood of scots pine radial growth in the forests of Ukrainian Polissia

    Directory of Open Access Journals (Sweden)

    V. P. Krasnov

    2016-12-01

    Full Text Available This research was conducted in regards to the distribution of 137Cs in the radial growth of pine forests within the humid pine forests of the Polissia, Ukraine. To set the value patterns we used radionuclide specific activity of 5-year rings that were formed before and after the accident. Based on the quantitative assessment of the modern distribution of 137Cs in pine wood, it showed much higher levels of radionuclide in the peripheral annual rings. This analysis was marked by very significant values that were found in the forests formed after the accident at Chernobyl. The latter can be explained as the movement of radionuclide from the wood formed after the accident and radioactive contamination of forest ecosystems due to global fallout.

  15. Growth of Fagus sylvatica saplings in an old-growth forest as affected by soil and light conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ponge, J.F.; Ferdy, J.B. [Museum National d`Histoire Naturelle, Brunoy (France). Lab. d`Ecologie Generale

    1997-12-01

    Studies were conducted on 41 five yr-old common beech (Fagus sylvatica) saplings collected in an old-growth beech wood (Fontainbleau forest, biological reserve of La Tillaie, France), under varying humus and light conditions, following gypsy moth (Lymantria dispar) caterpillar injuries. Aerial and subterranean parts of each sapling were described by means of 34 parameters and environmental conditions at the microsite, where each sapling was excavated, were characterized by 23 parameters. The development of beech saplings is strongly affected by microsite conditions. An increase in sapling size was associated with darkness of the A-horizon, typical of zones with poor mineralization of organic matter. Light conditions were more important in influencing the development of the root system than that of the aerial parts. Rooting depth was shallower and rate of mycorrhiza development by the black ascomycete Cenococcum geophilum was lower in microsites receiving incident light during the morning than in those never receiving incident light during this period. Results are discussed in the frame of survival of young beech individuals in varying environmental conditions, when submitted to competition by other vegetation and adverse climate conditions 41 refs, 1 fig, 4 tabs

  16. Diameter growth rates in tropical dry forests: contributions to the sustainable management of forests in the Bolivian Cerrado biogeographical province

    NARCIS (Netherlands)

    Lopez, L.; Villalba, R.; Peña-Claros, M.

    2012-01-01

    Growth ring variations were used to provide the rates in diameter growth for seven tree species in the Bolivian Cerrado biogeographical province. Ten to 50 trees were measured per species. Ring width measurements provided accurate data on the rates of tree growth. Variations in growth rates were

  17. 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...

  18. Growth and structure of a young Aleppo pine planted forest after thinning for diversification and wildfire prevention

    Directory of Open Access Journals (Sweden)

    J. Ruiz-Mirazo

    2013-04-01

    Full Text Available Aim of study: In the Mediterranean, low timber-production forests are frequently thinned to promote biodiversity and reduce wildfire risk, but few studies in the region have addressed such goals. The aim of this research was to compare six thinning regimes applied to create a fuelbreak in a young Aleppo pine (Pinus halepensis Mill. planted forest.Area of study: A semiarid continental high plateau in south-eastern Spain.Material and Methods: Three thinning intensities (Light, Medium and Heavy were combined with two thinning methods: i Random (tree selection, and ii Regular (tree spacing. Tree growth and stand structure measurements were made four years following treatments.Main results: Heavy Random thinning successfully transformed the regular tree plantation pattern into a close-to-random spatial tree distribution. Heavy Regular thinning (followed by the Medium Regular and Heavy Random regimes significantly reduced growth in stand basal area and biomass. Individual tree growth, in contrast, was greater in Heavy and Medium thinnings than in Light ones, which were similar to the Control.Research highlights: Heavy Random thinning seemed the most appropriate in a youngAleppo pine planted forest to reduce fire risk and artificial tree distribution simultaneously. Light Regular thinning avoids understocking the stand and may be the most suitable treatment for creating a fuelbreak when the undergrowth poses a high fire risk.Keywords: Pinus halepensis; Mediterranean; Forest structure; Tree growth; Wildfire risk; Diversity.

  19. Survival and growth of restored Piedmont riparian forests as affected by site preparation, planting stock, and planting aids

    Science.gov (United States)

    Chelsea M. Curtis; W. Michael Aust; John R. Seiler; Brian D. Strahm

    2015-01-01

    Forest mitigation sites may have poor survival and growth of planted trees due to poor drainage, compacted soils, and lack of microtopography. The effects of five replications of five forestry mechanical site preparation techniques (Flat, Rip, Bed, Pit, and Mound), four regeneration sources (Direct seed, Bare root, Tubelings, and Gallon), and three planting aids (None...

  20. Impacts of removing Chinese privet from riparian forests on plant communities and tree growth five years later

    Science.gov (United States)

    Jacob R. Hudson; James L. Hanula; Scott Horn

    2014-01-01

    An invasive shrub, Chinese privet (Ligustrum sinense Lour.), was removed from heavily infested riparian forests in the Georgia Piedmont in 2005 by mulching machine or chainsaw felling. Subsequent herbicide treatment eliminated almost all privet by 2007. Recovery of plant communities, return of Chinese privet, and canopy tree growth were measured on...

  1. Germination and initial growth of tree seedlings on deforested and natural forest soil at Dulhazara, Bangladesh

    Directory of Open Access Journals (Sweden)

    Md. Mohitul Hossain

    2012-12-01

    Full Text Available The destruction of natural forest is increasing due to urbanization, industrialization, settlement and for the agricultural expansion over last few decades, and studies for their recovery need to be undertaken. With this aim, this comparative study was designed to see the effects of deforested soil on germination and growth performance of five different tree species. In the experiment, five species namely Gmelina arborea, Swieteniamahagoni, Dipterocarpus turbinatus, Acacia auriculiformis and Syzygium grande were germinated for six weeks on seedbeds and raised in pots (25cm diameter, 30cm height, that were filled with two soil and type of land use: deforested and adjacent natural forest of Dulhazara Safari Park. Growth performance of seedling was observed up to 15 months based on height, collar diameter and biomass production at the end. Our results showed that the germination rate was almost similar in both type of land uses. Height growth of D. turbinatus, G. arborea and S. mahagoni seedlings was almost similar and A. auriculiformis and S. grande lower in deforested soil compared to natural forest soil, while collar diameter of A. auriculiformis, G. arborea, S. grande and S. mahagoni lower and D. turbinatus similar in deforested soil compared to natural forest soil. After uprooting at 19 months, S. mahagoni seedlings were showed significantly (p≤0.05 higher oven dry biomass, D. turbinatus and A. auriculiformis higher, while G. arborea showed significantly (p≤0.05 lower and S. grande almost similar oven dry biomass in deforested soil compared to natural forest soil. Oven dry biomass of D. turbinatus seedlings at 19 month age in deforested soil was 21.96g (n=5 and in natural forest soil 18.86g (n=5. However, differences in germination rate and growth performance for different tree species indicated that soil are not too much deteriorated through deforestation at Dulhazara and without any failure such deforested lands would be possible to

  2. The growth rate of Cladonia rangiferina and C. mitis in relation to forest characteristics in northeastern Finland

    Directory of Open Access Journals (Sweden)

    Timo Helle

    1983-05-01

    Full Text Available The growth rate of Cladonia rangiferina and C. mitis was studied in Kuusamo, northeastern Finland, where they share more than 90 percent of the total lichen biomass. The material was collected from 5 pine forests of different ages in Calluna-Cladina heaths. The length growth rate of C. rangiferina varied by site from 3.9 to 4.3 mmyr -' and that of C. mitis from 3.0 to 3.5 mmyr-1 C. rangiferina achieved the fastest growth in a younger (60 years shadowy forest; growth was slowest in a clear-felled area and in an old (180 years, already thinned forest. C. mitis grew fastest in a site with young (10 years old pine plants and slowest in a younger shadowy site. The results do not support suggestions that clear-felling itself might negatively influence the growth of lichens. However, it is important also from the point of view of range management to create a new forest as soon as possible, since both species studied here grew faster in young forests than in clear-felled areas.Harmaaporonjakalan ja mietoporonjakalan kasvunopeus eri-ikaisissa metsissa.Abstract in Finnish / Yhteenveto: Harmaaporonjakalan (Cladonia rangiferina ja mietoporonjakalan (Cladonia mitis kasvunopeutta tutkittiin Kuusamossa. Aineisto kerattiin 5 puustoltaan eri-ikaiselti jakalakankaalta. Harmaaporonjakala kasvoi pituutta keskimaarin 3.9 - 4.3 mm/v ja mietoporonjakala 3.0 - 3.5 mm/v kasvupaikasta riippuen. Harmaaporonjakalan kasvu oli nopeinta nuorehkossa (60 v tiheassa metsassa, hitainta paljaaksihakkuulla ja vanhassa (180 v, jo harventuneessa metsassa. Mietoporonjakala kasvoi nopeimmin 90 cm:n taimikossa ja hitaimmin varjoisimmalla kasvupaikalla. Tulosten perusteella on vaikea yhtya kasitykseen, etta paljaaksihakkuu sinansa vahentaa poronjakalien kasvunopeutta. Myos poronhoidon kannalta on kuitenkin tarkeaa, etta uusi metsa saadaan aikaan mahdollisimman nopeasti, silla molemmat lajit kasvavat nopeimmin eri-ikaisissa nuorissa metsissa.

  3. Retention and Solute Transport Properties in Disturbed and Undisturbed Soil Samples

    Directory of Open Access Journals (Sweden)

    Lívia Previatello da Silva

    Full Text Available ABSTRACT Solute transport parameters can be determined in miscible displacement experiments, usually performed in columns with disturbed (sieved soil samples. Experiments with undisturbed samples are uncommon, due to the difficulty of taking undisturbed samples at the size required for these experiments. Structural alteration of the disturbed material implies modifications in the pore geometry that determines hydraulic properties, including hydraulic conductivity and retention and properties related to miscible displacement. An existing model for prediction of breakthrough curves based on retention properties was tested using material from a medium-textured Ferralsol, and alterations caused by sample disturbance were investigated. Soil water retention curves and miscible displacement parameters were determined in breakthrough experiments with nitrate salts in columns filled with undisturbed and disturbed soil samples. Data obtained from the undisturbed samples showed a higher dispersion, suggesting homogenization of pore geometry and a reduction in the representative elementary volume by the disaggregation and sieving of the soil material. The transport parameters for nitrate determined in disturbed and undisturbed samples were significantly different and the model was able to simulate the observed breakthrough curves after fitting the pore connectivity parameter.

  4. Biological properties of disturbed and undisturbed Cerrado sensu stricto from Northeast Brazil.

    Science.gov (United States)

    Araújo, A S F; Magalhaes, L B; Santos, V M; Nunes, L A P L; Dias, C T S

    2017-03-01

    The aim of this study was to measure soil microbial biomass and soil surface fauna in undisturbed and disturbed Cerrado sensu stricto (Css) from Sete Cidades National Park, Northeast Brazil. The following sites were sampled under Cerrado sensu stricto (Css) at the park: undisturbed and disturbed Css (slash-and-burn agricultural practices). Total organic and microbial biomass C were higher in undisturbed than in disturbed sites in both seasons. However, microbial biomass C was higher in the wet than in the dry season. Soil respiration did not vary among sites but was higher in the wet than in the dry season. The densities of Araneae, Coleoptera, and Orthoptera were higher in the undisturbed site, whereas the densities of Formicidae were higher in the disturbed site. Non-metric multidimensional scaling analysis separated undisturbed from disturbed sites according to soil biological properties. Disturbance by agricultural practices, such as slash-and-burn, probably resulted in the deterioration of the biological properties of soil under native Cerrado sensu stricto in the Sete Cidades National Park.

  5. Comparison of Shear Strength Properties for Undisturbed and Reconstituted Parit Nipah Peat, Johor

    Science.gov (United States)

    Azhar, A. T. S.; Norhaliza, W.; Ismail, B.; Abdullah, M. E.; Zakaria, M. N.

    2016-11-01

    Shear strength of soil is required to determine the soil stability and design the foundations. Peat is known as a soil with complex natural formations which also contributes problems to the researchers, developers, engineers and contractors in constructions and infrastructures. Most researchers conducted experiment and investigation of shear strength on peat using shear box test and simple shear test, but only a few had discovered the behavior of peat using triaxial consolidated undrained test. The aim of this paper is to determine the undrained shear strength properties of reconstituted peat and undisturbed peat of Parit Nipah, Johor for comparison purposes. All the reconstituted peat samples were formed with the size that passed opening sieve 3.35 mm and preconsolidation pressure at 100 kPa. The result of undrained shear strength of reconstituted peat was 21kPa for cohesion with the angle of friction, 41° compare to the undisturbed peat with cohesion 10 kPa and angle of friction, 16°. The undrained shear strength properties result obtained shows that the reconstituted peat has higher strength than undisturbed peat. For relationship deviator stress-strain, σd max and excess pore pressure, Δu, it shows that both of undisturbed and reconstituted gradually increased when σ’ increased, but at the end of the test, the values are slightly dropped. The physical properties of undisturbed and reconstituted peat were also investigated to correlate with the undrained shear strength results.

  6. Alfalfa Responses to Gypsum Application Measured Using Undisturbed Soil Columns

    OpenAIRE

    Tirado-Corbalá, Rebecca; Slater, Brian K.; Dick, Warren A.; Barker, Dave

    2017-01-01

    Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG)] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1) untreated, (2) short-term (4-year annual applications of gypsum totaling 6720 kg ha−1), and (3) long-term (12-year annual applications of gypsum totaling 20,200 kg ha−1...

  7. Influence of thinning intensity and canopy type on Scots pine stand and growth dynamics in a mixed managed forest

    Energy Technology Data Exchange (ETDEWEB)

    Primicia, I.; Artázcoz, R.; Imbert, J.B.; Puertas, F.; Traver, M.C.; Castillo, F.J.

    2016-07-01

    Aim of the study: We analysed the effects of thinning intensity and canopy type on Scots pine growth and stand dynamics in a mixed Scots pine-beech forest. Area of the study: Western Pyrenees. Material and methods: Three thinning intensities were applied in 1999 (0, 20 and 30% basal area removed) and 2009 (0, 20 and 40%) on 9 plots. Within each plot, pure pine and mixed pine-beech patches are distinguished. All pine trees were inventoried in 1999, 2009 and 2014. The effects of treatments on the tree and stand structure variables (density, basal area, stand and tree volume), on the periodic annual increment in basal area and stand and tree volume, and on mortality rates, were analysed using linear mixed effects models. Main Results: The enhancement of tree growth was mainly noticeable after the second thinning. Growth rates following thinning were similar or higher in the moderate than in the severe thinning. Periodic stand volume annual increments were higher in the thinned than in the unthinned plots, but no differences were observed between the thinned treatments. We observed an increase in the differences of the Tree volume annual increment between canopy types (mixed < pure) over time in the unthinned plots, as beech crowns developed. Research highlights: Moderate thinning is suggested as an appropriate forest practice at early pine age in these mixed forests, since it produced higher tree growth rates than the severe thinning and it counteracted the negative effect of beech on pine growth observed in the unthinned plots. (Author)

  8. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem.

    Science.gov (United States)

    Seely, Brad; Welham, Clive; Scoullar, Kim

    2015-01-01

    Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine) for established stands due to increased moisture stress mortality.

  9. Application of a Hybrid Forest Growth Model to Evaluate Climate Change Impacts on Productivity, Nutrient Cycling and Mortality in a Montane Forest Ecosystem.

    Directory of Open Access Journals (Sweden)

    Brad Seely

    Full Text Available Climate change introduces considerable uncertainty in forest management planning and outcomes, potentially undermining efforts at achieving sustainable practices. Here, we describe the development and application of the FORECAST Climate model. Constructed using a hybrid simulation approach, the model includes an explicit representation of the effect of temperature and moisture availability on tree growth and survival, litter decomposition, and nutrient cycling. The model also includes a representation of the impact of increasing atmospheric CO2 on water use efficiency, but no direct CO2 fertilization effect. FORECAST Climate was evaluated for its ability to reproduce the effects of historical climate on Douglas-fir and lodgepole pine growth in a montane forest in southern British Columbia, Canada, as measured using tree ring analysis. The model was subsequently used to project the long-term impacts of alternative future climate change scenarios on forest productivity in young and established stands. There was a close association between predicted sapwood production and measured tree ring chronologies, providing confidence that model is able to predict the relative impact of annual climate variability on tree productivity. Simulations of future climate change suggest a modest increase in productivity in young stands of both species related to an increase in growing season length. In contrast, results showed a negative impact on stemwood biomass production (particularly in the case of lodgepole pine for established stands due to increased moisture stress mortality.

  10. Induced precipitation recycling (IPR) strategy to increase forest growth and regional rainfall

    Science.gov (United States)

    Layton, K. M.; Ellison, D.

    2013-12-01

    This presentation describes a project designed to capitalize on observed natural interactions between forest cover and the hydrologic cycle in order to increase available water supplies in arid regions, and to purify degraded water resources. An approach is presented to transition observed precipitation recycling effects into practical applications. Higher regional precipitation can be induced by promoting favorable conditions through afforestation and the irrigation of afforested land (IPR). Waste-water streams processed by the forest can increase local precipitation through the by-product evapotranspiration (ET). The proposed project illustrates how increased runoff from induced precipitation can help mitigate chronic regional water shortages in Southern California, using available degraded water resources. Each day, several hundred million gallons of treated sewage and excess storm water from the Los Angeles basin are channeled to the ocean for disposal. A portion of this can irrigate afforested land, initiating the IPR process. The afforested site likewise produces additional beneficial ecosystem services including nutrient management (of the sewage stream), carbon sequestration (from new growth), cooling of urban 'heat islands', and flood control. Research will explore interactions between ET plumes and local geography to aid the selection of afforestation sites and ensure increased precipitation over land, supporting the regional water supply. The IPR project is designed to manage risk and complexity through phased implementation. While no unproven technologies are used, there are uncertainties in applying theories from scientific research. During the 'pilot phase', initial afforestation site(s) will support research to examine the interactions of irrigated forest cover and IPR. As a proof of concept, this will develop the analytical basis for large-scale expansion. Once the theoretical foundation has been established, the project can expand to more irrigated

  11. Disturbance-mediated accelerated succession in two Michigan forest types

    Science.gov (United States)

    Abrams, Marc D.; Scott, Michael L.

    1989-01-01

    In northern lower Michigan, logging accelerated sugar maple (Acer saccharum) dominance in a northern white cedar (Thuja occidentals) community, and clear-cutting and burning quickly converted certain sites dominated by mature jack pine (Pinus banksiana) to early-succesional hardwoods, including Prunus, Populus, and Quercus. In both forest types the succeeding hardwoods should continue to increase in the future at the expense of the pioneer conifer species. In the cedar example, sugar maple was also increasing a an undisturbed, old-growth stand, but at a much reduced rate than in the logged stand. Traditionally, disturbance was through to set back succession to some earlier stage. However, out study sites and at least several other North American forest communities exhibited accelerated succession following a wide range of disturbances, including logging fire, ice storms, wind-throw, disease, insect attack, and herbicide spraying.

  12. Stand structure, recruitment and growth dynamics in mixed subalpine spruce and Swiss stone pine forests in the Eastern Carpathians.

    Science.gov (United States)

    Popa, Ionel; Nechita, Constantin; Hofgaard, Annika

    2017-11-15

    Natural subalpine forests are considered to be sensitive to climate change, and forest characteristics are assumed to reflect the prevalent disturbance regime. We hypothesize that stand history determines different stand structures. Based on large full inventory datasets (including tree biometric data, spatial coordinates, tree age, and basal area increment) we assessed the size structure, tree recruitment dynamics and radial growth patterns in three permanent plots along an altitudinal gradient in a mixed coniferous forest (Picea abies and Pinus cembra) in the Eastern Carpathians. Both discrete disturbances (large scale or small scale) and chronic disturbances (climate change) were identified as drivers of stand structure development in the studied plots. A stand replacing wind disturbance generated a unimodal bell-shaped size and age distribution for both species characterized by a sharp increase in post-disturbance recruitment. By contrast, small-scale wind-caused gaps led to a negative exponential diameter distribution for spruce and a left-asymmetric unimodal for pine. Climate-driven infilling processes in the upper subalpine forest were reflected as J-shaped size and age distributions for both species, but with pine predating spruce. The growth patterns for both species demonstrated an increased basal area increment since the early 1900s, with an emphasis in the last few decades, irrespective of stand history. Pine demonstrated a competitive advantage compared to spruce due to the higher growth rate and size at the same age. Recognition of combined discrete and chronic disturbances as drivers of the tree layer characteristics in a subalpine coniferous forest is essential in both stand history analyses and growth predictions. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Forest-stream linkages: effects of terrestrial invertebrate input and light on diet and growth of brown trout (Salmo trutta in a boreal forest stream.

    Directory of Open Access Journals (Sweden)

    Tibor Erős

    Full Text Available Subsidies of energy and material from the riparian zone have large impacts on recipient stream habitats. Human-induced changes, such as deforestation, may profoundly affect these pathways. However, the strength of individual factors on stream ecosystems is poorly understood since the factors involved often interact in complex ways. We isolated two of these factors, manipulating the flux of terrestrial input and the intensity of light in a 2×2 factorial design, where we followed the growth and diet of two size-classes of brown trout (Salmo trutta and the development of periphyton, grazer macroinvertebrates, terrestrial invertebrate inputs, and drift in twelve 20 m long enclosed stream reaches in a five-month-long experiment in a boreal coniferous forest stream. We found that light intensity, which was artificially increased 2.5 times above ambient levels, had an effect on grazer density, but no detectable effect on chlorophyll a biomass. We also found a seasonal effect on the amount of drift and that the reduction of terrestrial prey input, accomplished by covering enclosures with transparent plastic, had a negative impact on the amount of terrestrial invertebrates in the drift. Further, trout growth was strongly seasonal and followed the same pattern as drift biomass, and the reduction of terrestrial prey input had a negative effect on trout growth. Diet analysis was consistent with growth differences, showing that trout in open enclosures consumed relatively more terrestrial prey in summer than trout living in covered enclosures. We also predicted ontogenetic differences in the diet and growth of old and young trout, where we expected old fish to be more affected by the terrestrial prey reduction, but we found little evidence of ontogenetic differences. Overall, our results showed that reduced terrestrial prey inputs, as would be expected from forest harvesting, shaped differences in the growth and diet of the top predator, brown trout.

  14. Epiphytic and endophytic bacteria that promote growth of ethnomedicinal plants in the subtropical forests of Meghalaya, India.

    Science.gov (United States)

    Nongkhlaw, Fenella Mary War; Joshi, S R

    2014-12-01

    The present study was aimed to investigate the endophytic and epiphytic bacteria associated with selected ethnomedicinal plants from the pristine subtropical forests of Meghalaya and analyse them for plant growth promotion and antagonistic ability. This study is an attempt to explore plant associated bacteria which are beneficial to host plants, and thus aid in the conservation of ethnomedicinal plants of the studied subtropical forests, which are dwindling due to exploitation. The plant growth promotion parameters like indole acetic acid (IAA) production, mineral phosphate solubilisation, acid phosphatase activity, presence of 1-aminocyclopropane-1-carboxylic acid deaminase (ACC) gene, nitrogen fixation, cellulose digestion, chitin and pectin degrada- tion were screened among the isolates. The study revealed significant differences in bacterial population not only between the epiphytic and endophytic microhabitats, but also amongst the host plants. Out of the 70 isolated plant associated bacteria, Bacillus sp., Serratia sp., Pseudomonas sp., Pantoea sp., and Lysinibacillus sp. showed potent plant growth promotion properties. Bacillus siamensis C53 and B. subtilis cenB showed significant antagonistic activity against the tested pathogens. This study indicated the isolates inhabiting the plants prevalent in the subtropical sacred forests could be explored for use as plant growth promoters while practising the cultiva- tion and conservation of ethnomedicinal plants.

  15. Epiphytic and endophytic bacteria that promote growth of ethnomedicinal plants in the subtropical forests of Meghalaya, India

    Directory of Open Access Journals (Sweden)

    Fenella Mary War Nongkhlaw

    2014-12-01

    Full Text Available The present study was aimed to investigate the endophytic and epiphytic bacteria associated with selected ethnomedicinal plants from the pristine subtropical forests of Meghalaya and analyse them for plant growth promotion and antagonistic ability. This study is an attempt to explore plant associated bacteria which are beneficial to host plants, and thus aid in the conservation of ethnomedicinal plants of the studied subtropical forests, which are dwindling due to exploitation. The plant growth promotion parameters like indole acetic acid (IAA production, mineral phosphate solubilisation, acid phosphatase activity, presence of 1-aminocyclopropane-1-carboxylic acid deaminase (ACC gene, nitrogen fixation, cellulose digestion, chitin and pectin degradation were screened among the isolates. The study revealed significant differences in bacterial population not only between the epiphytic and endophytic microhabitats, but also amongst the host plants. Out of the 70 isolated plant associated bacteria, Bacillus sp., Serratia sp., Pseudomonas sp., Pantoea sp., and Lysinibacillus sp. showed potent plant growth promotion properties. Bacillus siamensis C53 and B. subtilis cenB showed significant antagonistic activity against the tested pathogens. This study indicated the isolates inhabiting the plants prevalent in the subtropical sacred forests could be explored for use as plant growth promoters while practising the cultivation and conservation of ethnomedicinal plants. Rev. Biol. Trop. 62 (4: 1295-1308. Epub 2014 December 01.

  16. Living and Dead Aboveground Biomass in Mediterranean Forests: Evidence of Old-Growth Traits in a Quercus pubescens Willd. s.l. Stand

    Directory of Open Access Journals (Sweden)

    Emilio Badalamenti

    2017-05-01

    Full Text Available For a long time, human impact has deeply simplified most of the forest ecosystems of the Mediterranean Basin. Here, forests have seldom had the chance to naturally develop a complex and multilayered structure, to host large and old trees and rich biological communities, approaching old-growth conditions. Also for this reason, limited information is currently available about Mediterranean old-growth forests, particularly with regard to deadwood. The main aim of this work is to help fill this critical knowledge gap. In Sicily (Italy, we identified a Quercus pubescens forest that seemed to show some typical old-growth features. Total living volume (360 m3 ha−1 and basal area (34 m2 ha−1 were, respectively, about 6 and 3 times higher than the averages recorded in the regional forest inventory for this forest type. Deadwood was particularly abundant, exceeding the threshold of 30 m3 ha−1, mainly represented by lying dead elements. Dead to live wood ratio reached 9%, a value close to the threshold of 10% considered for Mediterranean old-growth forests. As the investigated forest showed some typical old-growth traits, it deserves to be fully protected and could be a permanent monitoring area for studying deadwood and stand dynamics in mature Mediterranean stands.

  17. 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...

  18. Geomorphic and riparian forest influences on characteristics of large wood and large-wood jams in old-growth and second-growth forests in Northern Michigan, USA

    Science.gov (United States)

    Arthur E.L. Morris; P. Charles Goebel; Brian J. Palik

    2007-01-01

    Large wood (LW; pieces with diameter greater than 10 cm and length greater than 1 m) and large-wood jams (LWJs; two or more pieces of LW in contact with each other) are important components of stream ecosystems that are often distributed along stream channels in response to geomorphic and riparian forest factors that interact hierarchically. As a result, information on...

  19. 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.

  20. Potential impacts of using sewage sludge biochar on the growth of plant forest seedlings

    Directory of Open Access Journals (Sweden)

    Maria Isidoria Silva

    Full Text Available ABSTRACT: Sewage sludge has long been successfully used in the production of nursery plants; however, some restriction may apply due to its high pathogenic characteristics. The process of charring the organic waste significantly reduces that undesired component and may be as effective as the non-charred residue. The aim of this study was to evaluate the effect of sewage sludge biochar on the growth and morphological traits of eucalyptus ( Eucalyptus grandis L. seedlings, and compare results with those observed when using uncharred sewage sludge. Treatments were arranged in a completely randomized design, in a 2 x 2 factorial scheme, with four replications. Charred and non-charred sewage sludge were tested with and without NPK addition. A control treatment was also evaluated. Ten weeks old eucalyptus seedlings were transferred to the pots and grew for eight weeks. Chlorophyll content, plant height and stem diameter were measured at 0, 30 and 60 days after transplant. Shoot and root biomass were measured after plant harvest. Dickson Quality Index was calculated to evaluate the overall quality of seedlings. Biochar was effective in improving the seedlings quality, and had similar effects as the non-charred waste. Therefore, sewage sludge biochar has the potential to improve the process of production of forest species seedlings and further reduce the environmental risks associated with the use of non-charred sewage sludge.

  1. Relationship between types of urban forest and PM2.5 capture at three growth stages of leaves.

    Science.gov (United States)

    Nguyen, Thithanhthao; Yu, Xinxiao; Zhang, Zhenming; Liu, Mengmeng; Liu, Xuhui

    2015-01-01

    Particulate matter diameter ≤ 2.5 μm (PM2.5) causes direct harm to human health. Finding forms of urban forest systems that with the ability to reduce the amount of particulate matter in air effectively is the aim of this study. Five commonly cultivated kinds of urban forest types were studied in Beijing city at three stages of leaf growth. Results show that the urban forest system is capable of storing and capturing dust from the air. The types of shrubs and broadleaf trees that have the ability to capture PM2.5 from the air are most effective when leaves have fully developed. In the leafless season, the conifer and mixed tree types are the most effective in removing dust from the air. For all kinds of forest types and stages of leaf growth, the PM2.5 concentration is highest in the morning but lower in the afternoon and evening. Grassland cannot control particles suspended in the air, but can reduce dust pollution caused by dust from the ground blown by the wind back into the air. Copyright © 2014. Published by Elsevier B.V.

  2. Effects of Experimental Nitrogen and Phosphorus Addition on Litter Decomposition in an Old-Growth Tropical Forest

    OpenAIRE

    Chen, Hao; Dong, Shaofeng; Liu, Lei; Ma, Chuan; Zhang, Tao; Zhu, Xiaomin; Mo, Jiangming

    2013-01-01

    The responses of litter decomposition to nitrogen (N) and phosphorus (P) additions were examined in an old-growth tropical forest in southern China to test the following hypotheses: (1) N addition would decrease litter decomposition; (2) P addition would increase litter decomposition, and (3) P addition would mitigate the inhibitive effect of N addition. Two kinds of leaf litter, Schima superba Chardn. & Champ. (S.S.) and Castanopsis chinensis Hance (C.C.), were studied using the litterbag te...

  3. Longevity of Wood-Forced Pools in an Old-Growth Forest

    Science.gov (United States)

    Buffington, J. M.; Woodsmith, R. D.; Johnson, A. C.

    2009-12-01

    Wood debris plays an important role in scouring pools in forest channels and providing resultant habitat for aquatic organisms. We investigated the longevity of such pools in a gravel-bed river flowing through old-growth forest in southeastern Alaska by aging trees and “bear’s bread” fungi (Ganoderma applanatum, Fomitopsis pinicola) growing on pool-forming wood debris. Ages were determined by counting annual growth rings from cores and cross sections of trees and fungi growing on the wood debris. These ages are minimum values because they do not account for lag time between debris recruitment and seedling/spore establishment on the debris, nor do they account for flood scour that may periodically reset tree and fungi growth on the debris. The study stream has a gradient of about 1%, bankfull width and depth of 13.3 and 0.78 m, respectively, median grain size of 18 mm, a high wood loading (0.8 pieces/m), and a correspondingly low pool spacing (0.3 bankfull widths/pool), with 81% of the pools forced by wood debris. The size of wood debris in the study stream is large relative to the channel (average log length of 7.6 m and diameter of 0.35 m), rendering most debris immobile. Eighty-one pool-forming pieces of wood were dated over 1.2 km of stream length, with 28% of these pieces causing scour of more than one pool. In all, 122 wood-forced pools were dated, accounting for 38% of all pools at the site and 47% of the wood-forced pools. Fifty-three percent of the wood-forced pools lacked datable wood because these pieces either: were newly recruited; had been scoured by floods; or were contained below the active channel elevation, prohibiting vegetation establishment on the wood debris (the most common cause). The debris age distribution declined exponentially from 2 to 113 yrs., with a median value of 18 yrs. Similar exponential residence time distributions have been reported in other studies, but our analysis focused specifically on the ages of pool-forming wood

  4. Transport of a genetically modified Pseudomonas fluorescens and its parent strain through undisturbed tropical soil cores

    NARCIS (Netherlands)

    Guimaraes, V.F.; Cruz, I.V.; Hagler, A.N.; Mendonca-Hagler, L.C.; Elsas, van J.D.

    1997-01-01

    The transport of a genetically modified strain of Pseudomonas fluorescens, BR12, and its parent, BR5, was studied after irrigation of undisturbed clayey and sandy soil cores, simulating heavy tropical rainfall (56.6 mm/h). Vertical transport of both inoculant strains was detected in all soil cores.

  5. Dust emissions from undisturbed and disturbed, crusted playa surfaces: cattle trampling effects

    Science.gov (United States)

    Dry playa lake beds can be significant sources of fine dust emission. This study used a portable field wind tunnel to quantify the PM10 emissions from a bare, fine-textured playa surface located in the far northern Chihuahua Desert. The natural, undisturbed crust and its subjection to two levels of ...

  6. Community structure of arbuscular mycorrhizal fungi in undisturbed vegetation revealed by analyses of LSU rdna sequences

    DEFF Research Database (Denmark)

    Rosendahl, Søren; Holtgrewe-Stukenbrock, Eva

    2004-01-01

    Arbuscular mycorrhizal fungi (AMF) form a mutualistic symbiosis with plant roots and are found in most ecosystems. In this study the community structure of AMF in a clade of the genus Glomus was examined in undisturbed costal grassland using LSU rDNA sequences amplified from roots of Hieracium...

  7. AFLP fingerprinting of Kentucky bluegrass (Poa pratensis L.) from undisturbed Dutch grasslands: implications for conservation

    NARCIS (Netherlands)

    Treuren, van R.

    2008-01-01

    Undisturbed grasslands are considered rich sources of promising genotypes for the development of new varieties of Kentucky bluegrass (Poa pratensis L.). Grasslands that have not been resown with commercial cultivars nor treated with high doses of nitrogen fertilizer have become rare in the

  8. Rank reversals in tree growth along tree size, competition and climatic gradients for four forest canopy dominant species in Central Spain

    NARCIS (Netherlands)

    Sánchez-Gómez, D.; Zavala, M.A.; Schalkwijk, D.B.V.; Urbieta, I.R.; Valladares, F.

    2008-01-01

    Interspecific differences in tree growth patterns with respect to biotic and abiotic factors are key for understanding forest structure and dynamics, and predicting potential changes under climate change. • Repeated observations from the Spanish Forest Inventory (SFI) were used to parameterize

  9. Inventories and concentration profiles of 137Cs in undisturbed soils in the northeast of Buenos Aires Province, Argentina

    International Nuclear Information System (INIS)

    Montes, M.L.; Silva, L.M.S.; Sá, C.S.A.; Runco, J.; Taylor, M.A.; Desimoni, J.

    2013-01-01

    Inventories and vertical distribution of 137 Cs were determined in La Plata region undisturbed soils, Argentina. A mean inventory value of 891 ± 220 Bq/m 2 was established, which is compatible with the values expected from atmospheric weapon tests fallout. The study was complemented with pH, organic carbon fraction, texture and mineralogical soil analyses. Putting together Southern Hemisphere 137 Cs inventory data, it is possible to correlate these data with the mean annual precipitations. The large differences in 137 Cs concentration profiles were attributed to soil properties, especially the clay content and the pH values. A convection–dispersion model with irreversible retention was used to fit the activity concentration profiles. The obtained effective diffusion coefficient and effective convection velocity parameters values were in the range from 0.2 cm 2 /y to 0.4 cm 2 /y and from 0.23 cm/y to 0.43 cm/y, respectively. These data are in agreement with values reported in literature. In general, with the growth of clay content in the soil, there was an increase in the transfer rate from free to bound state. Finally, the highest transfer rate from free to bound state was obtained for soil pH value equal to 8. - Highlights: ► Inventories and vertical distribution of 137 Cs were determined in undisturbed soils of La Plata city region, Argentina. ► The study was complemented with soil analyses of pH, organic carbon, texture and mineralogy. ► Inventory data were correlated with the mean annual precipitations. ► Concentration profile differences were attributed to soil properties, especially the clay content and the pH value. ► A convection–dispersion model with irreversible retention was used to fit the measured 137 Cs concentration profiles.

  10. Population differentiation in tree-ring growth response of white fir (Abies concolor) to climate: Implications for predicting forest responses to climate change

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Deborah Bowne [Univ. of California, Berkeley, CA (United States)

    1993-01-01

    Forest succession models and correlative models have predicted 200--650 kilometer shifts in the geographic range of temperate forests and forest species as one response to global climate change. Few studies have investigated whether population differences may effect the response of forest species to climate change. This study examines differences in tree-ring growth, and in the phenotypic plasticity of tree-ring growth in 16-year old white fir, Abies concolor, from ten populations grown in four common gardens in the Sierra Nevada of California. For each population, tree-ring growth was modelled as a function of precipitation and degree-day sums. Tree-ring growth under three scenarios of doubled CO2 climates was estimated.

  11. The Elusive Boreal Forest Thaumarchaeota

    Directory of Open Access Journals (Sweden)

    Malin Bomberg

    2016-06-01

    Full Text Available In recent years, Archaea have, with increasing frequency, been found to colonize both agricultural and forest soils in temperate and boreal regions. The as yet uncultured group I.1c of the Thaumarchaeota has been of special interest. These Archaea are widely distributed in mature vegetated acidic soils, but little has been revealed of their physiological and biological characteristics. The I.1c Thaumarchaeota have been recognized as a microbial group influenced by plant roots and mycorrhizal fungi, but appear to have distinct features from their more common soil dwelling counterparts, such as the Nitrosotalea or Nitrososphaera. They appear to be highly dependent on soil pH, thriving in undisturbed vegetated soils with a pH of 5 or below. Research indicate that these Archaea require organic carbon and nitrogen sources for growth and that they may live both aerobically and anaerobically. Nevertheless, pure cultures of these microorganisms have not yet been obtained. This review will focus on what is known to date about the uncultured group I.1c Thaumarchaeota formerly known as the “Finnish Forest Soil” (FFS Archaea.

  12. Development of old-growth northern hardwoods on Bartlett Experimental Forest - a 22-year record

    Science.gov (United States)

    Stanley M. Filip; David A. Marquis; William B. Leak

    1960-01-01

    Northern hardwood forests provide the industries of New England with their most valuable woods: yellow birch and sugar maple for veneer, paper birch for turning stock, and other hardwood species for a variety of specialty products. As a result of recent developments in hardwood pulping, these northern hardwood forests now represent a tremendous reservoir of raw...

  13. Previous land use alters plant allocation and growth in forest herbs

    Science.gov (United States)

    Jennifer M. Fraterrigo; Monica G. Turner; Scott M. Pearson

    2006-01-01

    Former human practices can persistently influence forest ecosystems, particularly by altering the distribution and abundance of vegetation. Previous research has focused on the role of colonization success in governing plant community patterns in abandoned forests, but few studies have explored how changes in the performance of adult plants may contribute to...

  14. Old-growth Neotropical forests are shifting in species and trait composition

    NARCIS (Netherlands)

    Sande, van der M.T.; Arets, E.J.M.M.; Pena Claros, M.; Avila, L.A.; Roopsind, A.; Mazzei, L.; Ascarrunz, N.; Finegan, B.; Alarcón, A.; Caceres-Siani, Yasmani; Licona, J.C.; Ruschel, A.R.; Toledo, M.; Poorter, L.

    2016-01-01

    This dataset contains the underlaying data for the study: Tropical forests have long been thought to be in stable state, but recent insights indicate that global change is leading to shifts in forest dynamics and species composition. These shifts may be driven by environmental changes such as

  15. Structural overshoot of tree growth with climate variability and the global spectrum of drought-induced forest dieback.

    Science.gov (United States)

    Jump, Alistair S; Ruiz-Benito, Paloma; Greenwood, Sarah; Allen, Craig D; Kitzberger, Thomas; Fensham, Rod; Martínez-Vilalta, Jordi; Lloret, Francisco

    2017-09-01

    Ongoing climate change poses significant threats to plant function and distribution. Increased temperatures and altered precipitation regimes amplify drought frequency and intensity, elevating plant stress and mortality. Large-scale forest mortality events will have far-reaching impacts on carbon and hydrological cycling, biodiversity, and ecosystem services. However, biogeographical theory and global vegetation models poorly represent recent forest die-off patterns. Furthermore, as trees are sessile and long-lived, their responses to climate extremes are substantially dependent on historical factors. We show that periods of favourable climatic and management conditions that facilitate abundant tree growth can lead to structural overshoot of aboveground tree biomass due to a subsequent temporal mismatch between water demand and availability. When environmental favourability declines, increases in water and temperature stress that are protracted, rapid, or both, drive a gradient of tree structural responses that can modify forest self-thinning relationships. Responses ranging from premature leaf senescence and partial canopy dieback to whole-tree mortality reduce canopy leaf area during the stress period and for a lagged recovery window thereafter. Such temporal mismatches of water requirements from availability can occur at local to regional scales throughout a species geographical range. As climate change projections predict large future fluctuations in both wet and dry conditions, we expect forests to become increasingly structurally mismatched to water availability and thus overbuilt during more stressful episodes. By accounting for the historical context of biomass development, our approach can explain previously problematic aspects of large-scale forest mortality, such as why it can occur throughout the range of a species and yet still be locally highly variable, and why some events seem readily attributable to an ongoing drought while others do not. This

  16. Nutrient limitation on ecosystem productivity and processes of mature and old-growth subtropical forests in China.

    Directory of Open Access Journals (Sweden)

    Enqing Hou

    Full Text Available Nitrogen (N is considered the dominant limiting nutrient in temperate regions, while phosphorus (P limitation frequently occurs in tropical regions, but in subtropical regions nutrient limitation is poorly understood. In this study, we investigated N and P contents and N:P ratios of foliage, forest floors, fine roots and mineral soils, and their relationships with community biomass, litterfall C, N and P productions, forest floor turnover rate, and microbial processes in eight mature and old-growth subtropical forests (stand age >80 yr at Dinghushan Biosphere Reserve, China. Average N:P ratios (mass based in foliage, litter (L layer and mixture of fermentation and humus (F/H layer, and fine roots were 28.3, 42.3, 32.0 and 32.7, respectively. These values are higher than the critical N:P ratios for P limitation proposed (16-20 for foliage, ca. 25 for forest floors. The markedly high N:P ratios were mainly attributed to the high N concentrations of these plant materials. Community biomass, litterfall C, N and P productions, forest floor turnover rate and microbial properties were more strongly related to measures of P than N and frequently negatively related to the N:P ratios, suggesting a significant role of P availability in determining ecosystem production and productivity and nutrient cycling at all the study sites except for one prescribed disturbed site where N availability may also be important. We propose that N enrichment is probably a significant driver of the potential P limitation in the study area. Low P parent material may also contribute to the potential P limitation. In general, our results provided strong evidence supporting a significant role for P availability, rather than N availability, in determining ecosystem primary productivity and ecosystem processes in subtropical forests of China.

  17. 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

  18. Distribution of bioluminescent fungi across old-growth and secondary tropical rain forest in Costa Rica

    Directory of Open Access Journals (Sweden)

    Carolina Seas-Carvajal

    2013-06-01

    Full Text Available Most research on bioluminescent fungi is concentrated on their taxonomic relationships, while the basics of their natural history and ecological relationships are poorly understood. In this study, we compared the distribution of bioluminescent fungi between old-growth and secondary forest as related to four different soil types at the tropical rainforest of La Selva Biological Station in Costa Rica. The study was conducted during the wet season of 2009. Bioluminescent fungi were sought following eight different transects distributed evenly in old-growth and secondary forests across four different soil types, covering an area of 9 420m². We found fungi in four different substrates: litter, fallen branches, dead trunks, and roots, for a total of 61 samples. Correspondence analysis showed that the occurrence of fungi and soil types were related (inertia=0.21, p=0.071. We found a significant relationship between the presence of fungi and the distribution of soil types (X²=18.89, df=9, p=0.026. We found only three samples with fruiting bodies, two of which had Mycena and the other had one fungus of the order Xylariales (possibly Hypoxylon sp., Kretzschmariella sp., Xylaria sp.. Future work will concentrate on exploring other aspects of their ecology, such as their dispersal and substrate preference. This information will facilitate field identification and will foster more research on the distribution, seasonality, reproductive phenology and ecological requirements of this group of Fungi.La mayoría de las investigaciones sobre los hongos bioluminiscentes se ha centrado en relaciones taxonómicas. Los aspectos básicos de la historia natural y relaciones ecológicas de este grupo son poco conocidos. En este estudio, comparamos la distribución de hongos bioluminiscentes entre el bosque primario y el secundario en la Estación Biológica La Selva, Costa Rica en relación con cuatro tipos de suelo. El estudio se realizó durante la estación lluviosa

  19. Radial Growth Response of Black Spruce Stands Ten Years after Experimental Shelterwoods and Seed-Tree Cuttings in Boreal Forest

    Directory of Open Access Journals (Sweden)

    Miguel Montoro Girona

    2016-10-01

    Full Text Available Partial cutting is thought to be an alternative to achieve sustainable management in boreal forests. However, the effects of intermediate harvest intensity (45%–80% on growth remain unknown in black spruce (Picea mariana (Mill. B.S.P. stands, one of the most widely distributed boreal species with great commercial interest. In this study, we analysed the effect of three experimental shelterwood and one seed-tree treatments on tree radial growth in even-aged black spruce stands, 10 years after intervention. Our results show that radial growth response 8–10 years after cutting was 41% to 62% higher than in untreated plots, with stand structure, treatment, tree position relative to skidding trails, growth before cutting and time having significant interactions. The stand structure conditioned tree growth after cutting, being doubled in younger and denser stands. Tree spatial position had a pronounced effect on radial growth; trees at the edge of the skidding trails showed twice the increase in growth compared to interior trees. Dominant trees before cutting located close to the skidding trails manifested the highest growth response after cutting. This research suggests that the studied treatments are effective to enhance radial wood production of black spruce especially in younger stands, and that the edge effect must be considered in silvicultural management planning.

  20. Climate, canopy disturbance, and radial growth averaging in a second-growth mixed-oak forest in West Virginia, USA

    Science.gov (United States)

    James S. Rentch; B. Desta Fekedulegn; Gary W. Miller

    2002-01-01

    This study evaluated the use of radial growth averaging as a technique of identifying canopy disturbances in a thinned 55-year-old mixed-oak stand in West Virginia. We used analysis of variance to determine the time interval (averaging period) and lag period (time between thinning and growth increase) that best captured the growth increase associated with different...

  1. Combining Multi-Date Airborne Laser Scanning and Digital Aerial Photogrammetric Data for Forest Growth and Yield Modelling

    Directory of Open Access Journals (Sweden)

    Piotr Tompalski

    2018-02-01

    Full Text Available The increasing availability of highly detailed three-dimensional remotely-sensed data depicting forests, including airborne laser scanning (ALS and digital aerial photogrammetric (DAP approaches, provides a means for improving stand dynamics information. The availability of data from ALS and DAP has stimulated attempts to link these datasets with conventional forestry growth and yield models. In this study, we demonstrated an approach whereby two three-dimensional point cloud datasets (one from ALS and one from DAP, acquired over the same forest stands, at two points in time (circa 2008 and 2015, were used to derive forest inventory information. The area-based approach (ABA was used to predict top height (H, basal area (BA, total volume (V, and stem density (N for Time 1 and Time 2 (T1, T2. We assigned individual yield curves to 20 × 20 m grid cells for two scenarios. The first scenario used T1 estimates only (approach 1, single date, while the second scenario combined T1 and T2 estimates (approach 2, multi-date. Yield curves were matched by comparing the predicted cell-level attributes with a yield curve template database generated using an existing growth simulator. Results indicated that the yield curves using the multi-date data of approach 2 were matched with slightly higher accuracy; however, projections derived using approach 1 and 2 were not significantly different. The accuracy of curve matching was dependent on the ABA prediction error. The relative root mean squared error of curve matching in approach 2 for H, BA, V, and N, was 18.4, 11.5, 25.6, and 27.53% for observed (plot data, and 13.2, 44.6, 50.4 and 112.3% for predicted data, respectively. The approach presented in this study provides additional detail on sub-stand level growth projections that enhances the information available to inform long-term, sustainable forest planning and management.

  2. Tropical rain forest structure, tree growth and dynamics along a 2700-m elevational transect in Costa Rica.

    Science.gov (United States)

    Clark, David B; Hurtado, Johanna; Saatchi, Sassan S

    2015-01-01

    Rapid biological changes are expected to occur on tropical elevational gradients as species migrate upslope or go extinct in the face of global warming. We established a series of 9 1-ha plots in old-growth tropical rainforest in Costa Rica along a 2700 m relief elevational gradient to carry out long-term monitoring of tropical rain forest structure, dynamics and tree growth. Within each plot we mapped, identified, and annually measured diameter for all woody individuals with stem diameters >10 cm for periods of 3-10 years. Wood species diversity peaked at 400-600 m and decreased substantially at higher elevations. Basal area and stem number varied by less than two-fold, with the exception of the 2800 m cloud forest summit, where basal area and stem number were approximately double that of lower sites. Canopy gaps extending to the forest floor accounted for elevations. Height of highest crowns and the coefficient of variation of crown height both decreased with increasing elevation. Rates of turnover of individuals and of stand basal area decreased with elevation, but rates of diameter growth and stand basal area showed no simple relation to elevation. We discuss issues encountered in the design and implementation of this network of plots, including biased sampling, missing key meteorological and biomass data, and strategies for improving species-level research. Taking full advantage of the major research potential of tropical forest elevational transects will require sustaining and extending ground based studies, incorporation of new remotely-sensed data and data-acquisition platforms, and new funding models to support decadal research on these rapidly-changing systems.

  3. Tropical rain forest structure, tree growth and dynamics along a 2700-m elevational transect in Costa Rica.

    Directory of Open Access Journals (Sweden)

    David B Clark

    Full Text Available Rapid biological changes are expected to occur on tropical elevational gradients as species migrate upslope or go extinct in the face of global warming. We established a series of 9 1-ha plots in old-growth tropical rainforest in Costa Rica along a 2700 m relief elevational gradient to carry out long-term monitoring of tropical rain forest structure, dynamics and tree growth. Within each plot we mapped, identified, and annually measured diameter for all woody individuals with stem diameters >10 cm for periods of 3-10 years. Wood species diversity peaked at 400-600 m and decreased substantially at higher elevations. Basal area and stem number varied by less than two-fold, with the exception of the 2800 m cloud forest summit, where basal area and stem number were approximately double that of lower sites. Canopy gaps extending to the forest floor accounted for <3% of microsites at all elevations. Height of highest crowns and the coefficient of variation of crown height both decreased with increasing elevation. Rates of turnover of individuals and of stand basal area decreased with elevation, but rates of diameter growth and stand basal area showed no simple relation to elevation. We discuss issues encountered in the design and implementation of this network of plots, including biased sampling, missing key meteorological and biomass data, and strategies for improving species-level research. Taking full advantage of the major research potential of tropical forest elevational transects will require sustaining and extending ground based studies, incorporation of new remotely-sensed data and data-acquisition platforms, and new funding models to support decadal research on these rapidly-changing systems.

  4. Predicting impacts of future human population growth and development on occupancy rates of forest-dependent birds

    Science.gov (United States)

    Brown, Michelle L.; Donovan, Therese; Schwenk, W. Scott; Theobald, David M.

    2014-01-01

    Forest loss and fragmentation are among the largest threats to forest-dwelling wildlife species today, and projected increases in human population growth are expected to increase these threats in the next century. We combined spatially-explicit growth models with wildlife distribution models to predict the effects of human development on 5 forest-dependent bird species in Vermont, New Hampshire, and Massachusetts, USA. We used single-species occupancy models to derive the probability of occupancy for each species across the study area in the years 2000 and 2050. Over half a million new housing units were predicted to be added to the landscape. The maximum change in housing density was nearly 30 houses per hectare; however, 30% of the towns in the study area were projected to add less than 1 housing unit per hectare. In the face of predicted human growth, the overall occupancy of each species decreased by as much as 38% (ranging from 19% to 38% declines in the worst-case scenario) in the year 2050. These declines were greater outside of protected areas than within protected lands. Ninety-seven percent of towns experienced some decline in species occupancy within their borders, highlighting the value of spatially-explicit models. The mean decrease in occupancy probability within towns ranged from 3% for hairy woodpecker to 8% for ovenbird and hermit thrush. Reductions in occupancy probability occurred on the perimeters of cities and towns where exurban development is predicted to increase in the study area. This spatial approach to wildlife planning provides data to evaluate trade-offs between development scenarios and forest-dependent wildlife species.

  5. The impact of atmospheric deposition and climate on forest growth in European monitoring plots: An individual tree growth model

    NARCIS (Netherlands)

    Laubhann, D.; Sterba, H.; Reinds, G.J.; Vries, de W.

    2009-01-01

    In the climate change discussion, the possibility of carbon sequestration of forests plays an important role. Therefore, research on the effects of environmental changes on net primary productivity is interesting. In this study we investigated the influence of changing temperature, precipitation and

  6. Flowering phenology, growth forms, and pollination syndromes in tropical dry forest species: Influence of phylogeny and abiotic factors.

    Science.gov (United States)

    Cortés-Flores, Jorge; Hernández-Esquivel, Karen Beatriz; González-Rodríguez, Antonio; Ibarra-Manríquez, Guillermo

    2017-01-01

    Analyses of the influence of temporal variation in abiotic factors on flowering phenology of tropical dry forest species have not considered the possible response of species with different growth forms and pollination syndromes, while controlling for phylogenetic relationships among species. Here, we investigated the relationship between flowering phenology, abiotic factors, and plant functional attributes, while controlling for phylogenetic relationship among species, in a dry forest community in Mexico. We characterized flowering phenology (time and duration) and pollination syndromes of 55 tree species, 49 herbs, 24 shrubs, 15 lianas, and 11 vines. We tested the influence of pollination syndrome, growth form, and abiotic factors on flowering phenology using phylogenetic generalized least squares. We found a relationship between flowering duration and time. Growth form was related to flowering time, and the pollination syndrome had a more significant relationship with flowering duration. Flowering time variation in the community was explained mainly by abiotic variables, without an important phylogenetic effect. Flowering time in lianas and trees was negatively and positively correlated with daylength, respectively. Functional attributes, environmental cues, and phylogeny interact with each other to shape the diversity of flowering patterns. Phenological differentiation among species groups revealed multiples strategies associated with growth form and pollination syndromes that can be important for understanding species coexistence in this highly diverse plant community. © 2017 Botanical Society of America.

  7. Invertebrate populations of the deciduous forest: fluctuations and relations to weather

    National Research Council Canada - National Science Library

    Kendeigh, S. Charles

    1979-01-01

    The major objectives of the present study are to analyze (a) the composition and relative population sizes of the larger invertebrate fauna of relatively undisturbed, near-virgin, stands of deciduous forest, (b...

  8. Spatial Upscaling of Soil Respiration under a Complex Canopy Structure in an Old‐Growth Deciduous Forest, Central Japan

    Directory of Open Access Journals (Sweden)

    Vilanee Suchewaboripont

    2017-01-01

    Full Text Available The structural complexity, especially canopy and gap structure, of old‐growth forests affects the spatial variation of soil respiration (Rs. Without considering this variation, the upscaling of Rs from field measurements to the forest site will be biased. The present study examined responses of Rs to soil temperature (Ts and water content (W in canopy and gap areas, developed the best fit modelof Rs and used the unique spatial patterns of Rs and crown closure to upscale chamber measurements to the site scale in an old‐growth beech‐oak forest. Rs increased with an increase in Ts in both gap and canopy areas, but the effect of W on Rs was different between the two areas. The generalized linear model (GLM analysis identified that an empirical model of Rs with thecoupling of Ts and W was better than an exponential model of Rs with only Ts. Moreover, because of different responses of Rs to W between canopy and gap areas, it was necessary to estimate Rs in these areas separately. Consequently, combining the spatial patterns of Rs and the crown closure could allow upscaling of Rs from chamber‐based measurements to the whole site in the present study.

  9. A joint individual-based model coupling growth and mortality reveals that tree vigor is a key component of tropical forest dynamics.

    Science.gov (United States)

    Aubry-Kientz, Mélaine; Rossi, Vivien; Boreux, Jean-Jacques; Hérault, Bruno

    2015-06-01

    Tree vigor is often used as a covariate when tree mortality is predicted from tree growth in tropical forest dynamic models, but it is rarely explicitly accounted for in a coherent modeling framework. We quantify tree vigor at the individual tree level, based on the difference between expected and observed growth. The available methods to join nonlinear tree growth and mortality processes are not commonly used by forest ecologists so that we develop an inference methodology based on an MCMC approach, allowing us to sample the parameters of the growth and mortality model according to their posterior distribution using the joint model likelihood. We apply our framework to a set of data on the 20-year dynamics of a forest in Paracou, French Guiana, taking advantage of functional trait-based growth and mortality models already developed independently. Our results showed that growth and mortality are intimately linked and that the vigor estimator is an essential predictor of mortality, highlighting that trees growing more than expected have a far lower probability of dying. Our joint model methodology is sufficiently generic to be used to join two longitudinal and punctual linked processes and thus may be applied to a wide range of growth and mortality models. In the context of global changes, such joint models are urgently needed in tropical forests to analyze, and then predict, the effects of the ongoing changes on the tree dynamics in hyperdiverse tropical forests.

  10. Age structure and growth of degraded Populus euphratica floodplain forests in north-west China and perspectives for their recovery.

    Science.gov (United States)

    Westermann, Janneke; Zerbe, Stefan; Eckstein, Dieter

    2008-05-01

    The Populus euphratica floodplain forests along the lower reaches of the Tarim River in continental-arid Xinjiang (north-west China) have been declining in recent decades as a result of dam constructions and the withdrawal of water from the river. Since 2000, controlled flooding has been carried out to counteract this process of degradation. However, the consequences of a changing water regime for the floodplain ecosystem are not yet sufficiently investigated. In 2004 we sampled a total of 150 P. euphratica trees along two transects at the middle and lower reaches of the Tarim River to compare the age structure and growth of these two tree populations. The anthropogenic drawdown of the groundwater table had no effect on the average growth of the trees at the lower reaches. However, tree growth abruptly increased after controlled flooding, thus showing distinct signs of recovery.

  11. How Similar Are Forest Disturbance Maps Derived from Different Landsat Time Series Algorithms?

    Directory of Open Access Journals (Sweden)

    Warren B. Cohen

    2017-03-01

    Full Text Available Disturbance is a critical ecological process in forested systems, and disturbance maps are important for understanding forest dynamics. Landsat data are a key remote sensing dataset for monitoring forest disturbance and there recently has been major growth in the development of disturbance mapping algorithms. Many of these algorithms take advantage of the high temporal data volume to mine subtle signals in Landsat time series, but as those signals become subtler, they are more likely to be mixed with noise in Landsat data. This study examines the similarity among seven different algorithms in their ability to map the full range of magnitudes of forest disturbance over six different Landsat scenes distributed across the conterminous US. The maps agreed very well in terms of the amount of undisturbed forest over time; however, for the ~30% of forest mapped as disturbed in a given year by at least one algorithm, there was little agreement about which pixels were affected. Algorithms that targeted higher-magnitude disturbances exhibited higher omission errors but lower commission errors than those targeting a broader range of disturbance magnitudes. These results suggest that a user of any given forest disturbance map should understand the map’s strengths and weaknesses (in terms of omission and commission error rates, with respect to the disturbance targets of interest.

  12. Large zero-tension plate lysimeters for soil water and solute collection in undisturbed soils

    Directory of Open Access Journals (Sweden)

    A. Peters

    2009-09-01

    Full Text Available Water collection from undisturbed unsaturated soils to estimate in situ water and solute fluxes in the field is a challenge, in particular if soils are heterogeneous. Large sampling devices are required if preferential flow paths are present. We present a modular plate system that allows installation of large zero-tension lysimeter plates under undisturbed soils in the field. To investigate the influence of the lysimeter on the water flow field in the soil, a numerical 2-D simulation study was conducted for homogeneous soils with uni- and bimodal pore-size distributions and stochastic Miller-Miller heterogeneity. The collection efficiency was found to be highly dependent on the hydraulic functions, infiltration rate, and lysimeter size, and was furthermore affected by the degree of heterogeneity. In homogeneous soils with high saturated conductivities the devices perform poorly and even large lysimeters (width 250 cm can be bypassed by the soil water. Heterogeneities of soil hydraulic properties result into a network of flow channels that enhance the sampling efficiency of the lysimeter plates. Solute breakthrough into zero-tension lysimeter occurs slightly retarded as compared to the free soil, but concentrations in the collected water are similar to the mean flux concentration in the undisturbed soil. To validate the results from the numerical study, a dual tracer study with seven lysimeters of 1.25×1.25 m area was conducted in the field. Three lysimeters were installed underneath a 1.2 m filling of contaminated silty sand, the others deeper in the undisturbed soil. The lysimeters directly underneath the filled soil material collected water with a collection efficiency of 45%. The deeper lysimeters did not collect any water. The arrival of the tracers showed that almost all collected water came from preferential flow paths.

  13. Growth strategies and threshold responses to water deficit modulate effects of warming on tree seedlings from forest to alpine

    Science.gov (United States)

    Lazarus, Brynne E.; Castanha, Cristina; Germino, Matthew; Kueppers, Lara M.; Moyes, Andrew B.

    2018-01-01

    1.Predictions of upslope range shifts for tree species with warming are based on assumptions of moisture stress at lower elevation limits and low temperature stress at high elevation limits. However, recent studies have shown that warming can reduce tree seedling establishment across the entire gradient from subalpine forest to alpine via moisture limitation. Warming effects also vary with species, potentially resulting in community shifts in high elevation forests. 2.We examined the growth and physiology underlying effects of warming on seedling demographic patterns. We evaluated dry mass (DM), root length, allocation above- and belowground, and relative growth rate (RGR) of whole seedlings, and their ability to avoid or endure water stress via water-use efficiency and resisting turgor loss, for Pinus flexilis, Picea engelmannii and Pinus contorta seeded below, at, and above treeline in experimentally warmed, watered, and control plots in the Rocky Mountains, USA. We expected that growth and allocation responses to warming would relate to moisture status and that variation in drought tolerance traits would explain species differences in survival rates. 3.Across treatments and elevations, seedlings of all species had weak turgor-loss resistance, and growth was marginal with negative RGR in the first growth phase (-0.01 to -0.04 g/g/d). Growth was correlated with soil moisture, particularly in the relatively small-seeded P. contorta and P. engelmannii. P. flexilis, known to have the highest survivorship, attained the greatest DM and longest root but was also the slowest growing and most water-use-efficient. This was likely due to its greater reliance on seed reserves. Seedlings developed 15% less total DM, 25% less root DM, and 11% shorter roots in heated compared to unheated plots. Higher temperatures slightly increased DM, root length and RGR where soils were wettest, but more strongly decreased these variables under drier conditions. 4.Synthesis: The surprising

  14. FLORISTIC CHANGES IN A SUB-TROPICAL RAIN FOREST SUCCESSION

    Directory of Open Access Journals (Sweden)

    Rochadi Abdulhadi

    1992-02-01

    Full Text Available Floristic changes in a subtropical rain forest were assesed. Three regrowth forests aged 20 years, 50 years and 60 years and an undisturbed forest were sampled. The series of sites sho floristic changes that would be expected in a successional sequence. The regrowth forests were dominated by the secondary species but the primary species occur from the early stage. The oldest regrowth (60 year old-site was still well short of regaining its original condition.

  15. Carbon dioxide and methane fluxes in grazed and undisturbed mountain peatlands in the Ecuadorian Andes

    Directory of Open Access Journals (Sweden)

    M.E. Sánchez

    2017-10-01

    Full Text Available Peatlands are widespread throughout the tropical Andean páramo. Despite the large carbon stocks in these ecosystems, carbon dioxide (CO2 and methane (CH4 flux data are lacking. In addition, cattle grazing is widespread in the páramo and could alter gas fluxes. Therefore, our objectives were to measure CO2 and CH4 fluxes with the static chamber technique in an undisturbed and in an intensively cattle grazed peatland in the mountains of Ecuador. We found that hummocks in the undisturbed site had higher net ecosystem exchange (NEE, gross primary production (GPP, ecosystem respiration (ER, and CH4 fluxes, compared to lawns. In contrast, microtopography at the grazed site did not predict CO2 fluxes, whereas vegetation cover was correlated for all three metrics (NEE, ER, and GPP. At low vegetation cover, NEE was positive (losing carbon. CH4 emissions in the undisturbed site were low (8.1 mg CH4 m-2 d-1. In contrast, CH4 emissions at the grazed site were much greater (132.3 mg CH4 m-2 d-1. This is probably attributable to trampling and nutrient inputs from cattle. In summary, the two peatlands differed greatly in CO2 and CH4 exchange rates, which could be due to the variation in climate and hydrology, or alternatively to intensive grazing by cattle.

  16. Presettlement and modern disturbance regimes in coast redwood forests: Implications for the conservation of old-growth stands

    Science.gov (United States)

    Lorimer, Craig G.; Porter, Daniel J.; Madej, Mary Ann; Stuart, John D.; Veirs, Stephen D.; Norman, Steven P.; O'Hara, Kevin L.; Libby, William J.

    2009-01-01

    Coast redwood (Sequoia sempervirens), a western North American conifer of ancient lineage, has a paradoxical combination of late-successional characteristics and strong adaptations to disturbance. Despite its shade tolerance and heavy dominance of the canopy on many sites, redwood saplings are uncommon in upland old-growth stands. Information needed to ensure the conservation of old-growth redwood forests has been limited. In this review paper, we integrate evidence on redwood biology with data on the historic and modern disturbance regimes to help clarify the degree to which key attributes of redwood forests may have been dependent upon periodic disturbance. Available evidence suggests that episodes of fire, flooding, and slope failure prior to European settlement were frequent but predominantly of low to moderate severity and extent, resulting in broadly uneven-aged forests. The majority of fires prior to European settlement were apparently of human origin. Frequency and severity of the major disturbance agents have been radically changed in modern times. Fires have been largely excluded, and flooding has been altered in ways that have often been detrimental to old-growth redwoods on alluvial terraces. However, because of the apparent anthropogenic origin of most presettlement fires, the long-term evolutionary role of fire for coast redwood is ecologically ambiguous. With fire exclusion, redwood possibly could be displaced to some extent on upland sites by increasing abundance of fire-sensitive competitors. Alternatively, redwood may be able to maintain dominance by vegetative sprouting and new seedling establishment on root-wad mounds, fallen logs, and on soil exposed by slope failure. Future research priorities are suggested that will help resolve some of the current ambiguities.

  17. Forest Growth Responses to Drought at Short- and Long-Term Scales in Spain: Squeezing the Stress Memory from Tree Rings

    Directory of Open Access Journals (Sweden)

    J. Julio Camarero

    2018-02-01

    Full Text Available Drought-triggered declines in forest productivity and associated die-off events have increased considerably due to climate warming in the last decades. There is an increasing interest in quantifying the resilience capacity of forests against climate warming and drought to uncover how different stands and tree species will resist and recover after more frequent and intense droughts. Trees form annual growth rings that represent an accurate record of how forest growth responded to past droughts. Here we use dendrochronology to quantify the radial growth of different forests subjected to contrasting climatic conditions in Spain during the last half century. Particularly, we considered four climatically contrasting areas where dominant forests showed clear signs of drought-induced dieback. Studied forests included wet sites dominated by silver fir (Abies alba in the Pyrenees and beech (Fagus sylvatica stands in northern Spain, and drought-prone sites dominated by Scots pine (Pinus sylvestris in eastern Spain and black pine (Pinus nigra in the semi-arid south-eastern Spain. We quantified the growth reduction caused by different droughts and assessed the short-and long-term resilience capacity of declining vs. non-declining trees in each forest. In all cases, drought induced a marked growth reduction regardless tree vigor. However, the capacity to recover after drought (resilience at short- and long-term scales varied greatly between declining and non-declining individuals. In the case of beech and silver fir, non-declining individuals presented greater growth rates and capacity to recover after drought than declining individuals. For Scots pine, the resilience to drought was found to be lower in recent years regardless the tree vigor, but the growth reduction caused by successive droughts was more pronounced in declining than in non-declining individuals. In the black pine forest an extreme drought induced a marked growth reduction in declining

  18. Forest-atmosphere carbon dioxide exchange in eastern Siberia

    Science.gov (United States)

    D.Y. Hollinger; F.M. Kelliher; E.-D. Schulze; G. Bauer; A., et al. Arneth

    1998-01-01

    We investigated the daily exchange of C02 between undisturbed Larix gmelinii (Rupr.) Rupr forest and the atmosphere at a remote Siberian site during July and August of 1993. Our goal was to measure and partition total C02 exchanges into aboveground and belowground components by measuring forest and...

  19. Soils, water and nutrients in a forest ecosystem in Suriname

    NARCIS (Netherlands)

    Poels, R.L.H.

    1987-01-01

    Water and nutrient flows were measured in catchments on strongly weathered loamy sediments of the Zanderij formation in Suriname under undisturbed forest and forest silviculturally treated whereby 40 % of the biomass was killed. The topography of the two catchment areas studied (each of

  20. Influence of soil conditions on dissolved organic matter leached from forest and wetland soils: a controlled growth chamber study.

    Science.gov (United States)

    Kim, Eun-Ah; Nguyen, Hang Vo-Minh; Oh, Hae Sung; Hur, Jin; Choi, Jung Hyun

    2016-03-01

    This study investigated the effects of various soil conditions, including drying-rewetting, nitrogen deposition, and temperature rise, on the quantities and the composition of dissolved organic matter leached from forest and wetland soils. A set of forest and wetland soils with and without the nitrogen deposition were incubated in the growth chambers under three different temperatures. The moisture contents were kept constant, except for two-week drying intervals. Comparisons between the original and the treated samples revealed that drying-rewetting was a crucial environmental factor driving changes in the amount of dissolved organic carbon (DOC). The DOC was also notably increased by the nitrogen deposition to the dry forest soil and was affected by the temperature of the dry wetland soil. A parallel factor (PARAFAC) analysis identified three sub-fractions of the fluorescent dissolved organic matter (FDOM) from the fluorescence excitation-emission matrices (EEMs), and their compositions depended on drying-rewetting. The data as a whole, including the DOC and PARAFAC components and other optical indices, were possibly explained by the two main variables, which were closely related with the PARAFAC components and DOC based on principal component analysis (PCA). Our results suggested that the DOC and PARAFAC component information could provide a comprehensive interpretation of the changes in the soil-leached DOM in response to the different environmental conditions.

  1. Early subtropical forest growth is driven by community mean trait values and functional diversity rather than the abiotic environment.

    Science.gov (United States)

    Kröber, Wenzel; Li, Ying; Härdtle, Werner; Ma, Keping; Schmid, Bernhard; Schmidt, Karsten; Scholten, Thomas; Seidler, Gunnar; von Oheimb, Goddert; Welk, Erik; Wirth, Christian; Bruelheide, Helge

    2015-09-01

    While functional diversity (FD) has been shown to be positively related to a number of ecosystem functions including biomass production, it may have a much less pronounced effect than that of environmental factors or species-specific properties. Leaf and wood traits can be considered particularly relevant to tree growth, as they reflect a trade-off between resources invested into growth and persistence. Our study focussed on the degree to which early forest growth was driven by FD, the environment (11 variables characterizing abiotic habitat conditions), and community-weighted mean (CWM) values of species traits in the context of a large-scale tree diversity experiment (BEF-China). Growth rates of trees with respect to crown diameter were aggregated across 231 plots (hosting between one and 23 tree species) and related to environmental variables, FD, and CWM, the latter two of which were based on 41 plant functional traits. The effects of each of the three predictor groups were analyzed separately by mixed model optimization and jointly by variance partitioning. Numerous single traits predicted plot-level tree growth, both in the models based on CWMs and FD, but none of the environmental variables was able to predict tree growth. In the best models, environment and FD explained only 4 and 31% of variation in crown growth rates, respectively, while CWM trait values explained 42%. In total, the best models accounted for 51% of crown growth. The marginal role of the selected environmental variables was unexpected, given the high topographic heterogeneity and large size of the experiment, as was the significant impact of FD, demonstrating that positive diversity effects already occur during the early stages in tree plantations.

  2. Artificial recharge of groundwater through sprinkling infiltration: impacts on forest soil and the nutrient status and growth of Scots pine.

    Science.gov (United States)

    Nöjd, Pekka; Lindroos, Antti-Jussi; Smolander, Aino; Derome, John; Lumme, Ilari; Helmisaari, Heljä-Sisko

    2009-05-01

    We studied the chemical changes in forest soil and the effects on Scots pine trees caused by continuous sprinkling infiltration over a period of two years, followed by a recovery period of two years. Infiltration increased the water input onto the forest soil by a factor of approximately 1000. After one year of infiltration, the pH of the organic layer had risen from about 4.0 to 6.7. The NH(4)-N concentration in the organic layer increased, most probably due to the NH(4) ions in the infiltration water, as the net N mineralization rate did not increase. Sprinkling infiltration initiated nitrification in the mineral soil. Macronutrient concentrations generally increased in the organic layer and mineral soil. An exception, however, was the concentration of extractable phosphorus, which decreased strongly during the infiltration period and did not show a recovery within two years. The NO(3)-N and K concentrations had reverted back to their initial level during the two-year recovery period, while the concentrations of Ca, Mg and NH(4)-N were still elevated. Nutrient concentrations in the pine needles increased on the infiltrated plots. However, the needle P concentration increased, despite the decrease in plant-available P in the soil. Despite the increase in the nutrient status, there were some visible signs of chlorosis in the current-year needles after two years of infiltration. The radial growth of the pines more than doubled on the infiltrated plots, which suggests that the very large increase in the water input onto the forest floor had no adverse effect on the functioning of the trees. However, a monitoring period of four years is not sufficient for detecting potential long term detrimental effects on forest trees.

  3. Spatial models reveal the microclimatic buffering capacity of old-growth forests

    Science.gov (United States)

    Sarah J. K. Frey; Adam S. Hadley; Sherri L. Johnson; Mark Schulze; Julia A. Jones; Matthew. G. Betts

    2016-01-01

    Climate change is predicted to cause widespread declines in biodiversity, but these predictions are derived from coarse-resolution climate models applied at global scales. Such models lack the capacity to incorporate microclimate variability, which is critical to biodiversity microrefugia. In forested montane regions, microclimate is thought to be influenced by...

  4. Long-term mortality rates and spatial patterns in an old-growth forest

    Science.gov (United States)

    Emily J. Silver; Shawn Fraver; Anthony W. D' Amato; Tuomas Aakala; Brian J. Palik

    2013-01-01

    Understanding natural mortality patterns and processes of forest tree species is increasingly important given projected changes in mortality owing to global change. With this need in mind, the rate and spatial pattern of mortality was assessed over an 89-year period in a natural-origin Pinus resinosa (Aiton)-dominated system to assess these processes...

  5. Short-term dynamics of second-growth mixed mesophytic forest strata in West Virginia

    Science.gov (United States)

    Cynthia C. Huebner; Steven L. Stephenson; Harold S. Adams; Gary W. Miller

    2007-01-01

    The short-term dynamics of mixed mesophytic forest strata in West Virginia were examined using similarity analysis and linear correlation of shared ordination space. The overstory tree, understory tree, shrub/vine, and herb strata were stable over a six year interval, whereas the tree seedling and sapling strata were unstable. All strata but the shrub/vine and tree...

  6. 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...

  7. Forecasting Forest Inventory Using Imputed Tree Lists for LiDAR Grid Cells and a Tree-List Growth Model

    Directory of Open Access Journals (Sweden)

    Sean M. Lamb

    2018-03-01

    Full Text Available A method to forecast forest inventory variables derived from light detection and ranging (LiDAR would increase the usefulness of such data in future forest management. We evaluated the accuracy of forecasted inventory from imputed tree lists for LiDAR grid cells (20 × 20 m in spruce (Picea sp. plantations and tree growth predicted using a locally calibrated tree-list growth model. Tree lists were imputed by matching measurements from a library of sample plots with grid cells based on planted species and the smallest sum of squared difference between six inventory variables. Total and merchantable basal area, total and merchantable volume, Lorey’s height, and quadratic mean diameter increments predicted using imputed tree lists were highly correlated (0.75–0.86 with those from measured tree lists in 98 validation plots. Percent root mean squared error ranged from 12.8–49.0% but was much lower (4.9–13.5% for plots with ≤10% LiDAR-derived error for all plot-matched variables. When compared with volumes from 15 blocks harvested 3–5 years after LiDAR acquisition, average forecasted volume differed by only 1.5%. To demonstrate the novel application of this method for operational management decisions, annual commercial thinning was planned at grid-cell resolution from 2018–2020 using forecasted inventory variables and commercial thinning eligibility rules.

  8. Survival and growth of tree seedlings as a function of seed size in a gallery forest under restoration

    Directory of Open Access Journals (Sweden)

    Leonardo Gallo Macera

    2017-09-01

    Full Text Available ABSTRACT Seed size is commonly related to higher rates of emergence and survival, and biomass of seedlings when introduced by direct seeding. However, few studies have evaluated whether this relationship persists when species are reintroduced as seedlings or if this effect persists after seed reserves decline. This study evaluated the effect of seed size (mass on the probability of survival and growth of seedlings of nine native tree species introduced into a pasture area, which was originally a gallery forest in the state of São Paulo in Southeastern Brazil. The experiment occurred over the course of 24 months, in which was divided into three separate time intervals: 14 to 61 days, 61 days to 12 months, and 12 to 24 months. Seedling survival in the field was high for all three time-intervals. Seed mass positively influenced the probability of seedling survival throughout all three time-intervals after planting, but the intensity of this effect decreased with time. Species with smaller seeds exhibited higher relative growth rates (height, but only until the end of the first year. Our results suggest that seed mass is a functional trait that can predict the probability of the establishment of individual trees during forest restoration.

  9. Site quality influence over understory plant diversity in old-growth and harvested Nothofagus pumilio forests

    Energy Technology Data Exchange (ETDEWEB)

    Gallo, E. A.; Lencinas, M. V.; Martinez-Pastur, G. J.

    2013-05-01

    Aim of study: The effects and interactions of shelter wood forest harvesting and site qualities over understory plant species diversity and composition were compared among primary and harvested Nothofagus pumilio forests. Area of study: Tierra del Fuego (Argentina), on three pure conditions (one and six year-old harvested, and primary without previous harvesting forests) and three site qualities (high, medium and low). Material and Methods: Understory richness and cover (%) were registered in five replicates of 1 hectare each per treatment. Taxonomic species were classified in categories (groups, origin and life forms). Two-way ANOVAs and multivariate analyses were conducted. Main results: Shelterwood harvesting and site quality significantly influenced understory cover and richness, which allow the introduction of native and exotic species and increasing of dicot and monocot covers. In dicots, monocots, exotics and total groups, higher richness and covers were related to time. Meanwhile, cover reached similar high values in all site qualities on dicot, native and total groups. On the other hand, monocot and exotic richness and cover remain similar in primary and recently harvested forests, and greatly increased in old harvested forests. Mosses and ferns were among the most sensitive groups. Research highlights: Impacts of shelterwood cut depend on site quality of the stands and time since harvesting occurs. For this, different site quality stands should received differential attention in the development of conservation strategies, as well as variations in the shelterwood implementation (as irregularity and patchiness) should be considered to better promote understory plant species conservation inside managed areas. (Author) 45 refs.

  10. Characteristics of Decomposition Powers of L-Band Multi-Polarimetric SAR in Assessing Tree Growth of Industrial Plantation Forests in the Tropics

    Directory of Open Access Journals (Sweden)

    Yoshio Yamaguchi

    2012-10-01

    Full Text Available A decomposition scheme was applied to ALOS/PALSAR data obtained from a fast-growing tree plantation in Sumatra, Indonesia to extract tree stem information and then estimate the forest stand volume. The scattering power decomposition of the polarimetric SAR data was performed both with and without a rotation matrix and compared to the following field-measured forest biometric parameters: tree diameter, tree height and stand volume. The analytical results involving the rotation matrix correlated better than those without the rotation matrix even for natural scattering surfaces within the forests. Our primary finding was that all of the decomposition powers from the rotated matrix correlated significantly to the forest biometric parameters when divided by the total power. The surface scattering ratio of the total power markedly decreased with the forest growth, whereas the canopy and double-bounce scattering ratios increased. The observations of the decomposition powers were consistent with the tree growth characteristics. Consequently, we found a significant logarithmic relationship between the decomposition powers and the forest biometric parameters that can potentially be used to estimate the forest stand volume.

  11. 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.

  12. Quantifying canopy complexity and effects on productivity and resilience in late-successional hemlock-hardwood forests.

    Science.gov (United States)

    Fahey, Robert T; Fotis, Alexander T; Woods, Kerry D

    2015-04-01

    The regrowing forests of eastern North America have been an important global C sink over the past 100+ years, but many are now transitioning into late succession. The consequences of this transition are unclear due to uncertainty around the C dynamics of old- growth forests. Canopy structural complexity (CSC) has been shown to be an important source of variability in C dynamics in younger forests (e.g., in productivity and resilience to disturbance), but its role in late-successional forests has not been widely addressed. We investigated patterns of CSC in two old-growth forest landscapes in the Upper Peninsula of Michigan, USA, to assess factors associated with CSC and its influence on productivity and disturbance resilience (to moderate-severity windstorm). CSC was quantified using a portable below-canopy LiDAR (PCL) system in 65 plots that also had long-term (50-70+ years). inventory data, which were used to quantify aboveground net primary productivity (ANPP), disturbance history, and stand characteristics. We found high and variable CSC relative to younger forests across a suite of PCL-derived metrics. Variation in CSC was driven by species composition and size structure, rather than disturbance history or site characteristics. Recent moderate severity wind disturbance decreased plot-scale CSC, but increased stand-scale variation in CSC. The strong positive correlation between CSC and productivity illustrated in younger forests was not present in undisturbed portions of these late-successional ecosystems. Moderate severity disturbance appeared to reestablish the positive link between CSC and productivity, but this relationship was scale and severity dependent. A positive CSC-productivity relationship was evident at the plot scale with low-severity, dispersed disturbance, but only at a patch scale in more severely disturbed areas. CSC does not appear to strongly correlate With variation in productivity in undisturbed old-growth forests, but may play a very

  13. AVHRR imagery used to identify hurricane damage in a forested wetland of Louisiana

    Science.gov (United States)

    Ramsey, Elijah W.; Chappell, D.K.; Baldwin, D.G.

    1997-01-01

    Certain events provide a unique opportunity to test the monitoring capability of AVHBR imagery. On 26 August 1992, Hurricane Andrew passed through Louisiana, impacting a large area of forested wetlands. One response to the widespread defoliation resulting from the hurricane impact was an abnormal bloom of new leaves and new growth in the underlying vegetation between September and October. To capture this atypical phenology, a time sequence of AVHRR images was transformed into a normalized difference vegetation index, NDVI, as an indicator of vegetation changes in the forest impacted by the passage of a hurricane. Using geographic information system functions, three sites in the impacted forest were vectorized as polygons, and the inclusive pixels were extracted for subsequent graphical and univariate statistical analysis. Temporal curves of mean NDVIs for the three sites for before, during, and after the hurricane passage, and aggregate curves of the impacted forest to an undisturbed forest, were compared. These comparisons corroborated the atypical phenology of the impacted forested wetland and directly related the cause to the hurricane passage.

  14. Influence of light conditions on the allometry and growth of the understory palm Geonoma undata subsp. edulis (Arecaceae) of neotropical cloud forests.

    Science.gov (United States)

    Sylvester, Olivia; Avalos, Gerardo

    2013-12-01

    Knowledge on the growth responses of understory palms to changing light conditions within neotropical cloud forests is limited. The low light regime of these environments, in addition to persistent cloudiness, low ambient temperatures, and slow nutrient cycles, imposes significant constraints on biomass accumulation. Here, we evaluate how changes in the understory light conditions influenced the allometry and growth of G. undata subsp. edulis in two cloud forests in Costa Rica. We examined the structural relationships between stem diameter, stem height, and crown area in reproductive and nonreproductive individuals. We related the variation in stem growth and crown area with allometry, leaf production and longevity, and light conditions that we measured using hemispherical photographs over 1 year. The allometric and growth pattern of G. undata subsp. edulis was characterized by its investment in crown area, which was strongly and positively related to increments in palm height and reproduction. Growth, measured as the increase in crown area and stem height, was not explained by the variation in the light regime spanning 1 year. However, reproductive individuals were generally taller, more slender, and had larger leaf areas than nonreproductive individuals. Our results demonstrated that stem growth responses were mostly controlled by initial crown size rather than by temporal differences in the understory light regimes of cloud forests. These results suggest that cloud forest understory palms have a limited capacity to respond to light changes and rely mostly on an opportunistic strategy for biomass accumulation and reproduction.

  15. Effect of Chitosan on Disease Control and Growth of Scots Pine (Pinus sylvestris L. in a Forest Nursery

    Directory of Open Access Journals (Sweden)

    Marta Aleksandrowicz-Trzcińska

    2015-09-01

    Full Text Available Chitosan has become a promising biological agent for disease control and plant growth promotion. The objective of this study was to assess the effects of chitosan, applied as an active ingredient of Beta-chikol (Poli-Farm, Łowicz, Poland, to control damping-off and Lophodermium needle cast on Scots pine seedlings growing in field conditions. Beta-chikol was used for seed treatment and as a foliar spray at recommended rates and concentrations. For each experimental variant (chitosan, fungicides, unprotected, inventories of seedlings were performed, after germination and again after six weeks. In the aboveground parts of seedlings, the concentration of endogenous salicylic acid was determined by HPLC. At the end of the growing season, seedling growth parameters were determined. Beta-chikol used as foliar spray limited infection by the damping-off fungi but was ineffective when used as a seed treatment. Lophodermium needle cast was not observed during the study period. After the application of Beta-chikol, the concentration of salicylic acid did not increase. The application of Beta-chikol enhanced all growth parameters under investigation. Our results indicate the possibility of using chitosan in the form of Beta-chikol to stimulate plant growth and protect pine seedlings against parasitic damping-off in forest nurseries.

  16. Forest drainage

    Science.gov (United States)

    R.W. Skaggs; S. Tian; G.M. Chescheir; Devendra Amatya; M.A. Youssef

    2016-01-01

    Most of the world's 4030 million ha of forested lands are situated on hilly, mountainous or well-drained upland landscapes where improved drainage is not needed. However, there are millions of hectares of poorly drained forested lands where excessively wet soil conditions limit tree growth and access for harvesting and other management activities. Improved or...

  17. Forecasting tree growth in coppiced and high forests in the Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Stojanović, Marko; Sánchez-Salguero, R.; Levanič, T.; Szatniewska, Justyna; Pokorný, Radek; Linares, J. C.

    2017-01-01

    Roč. 405, DEC (2017), s. 56-68 ISSN 0378-1127 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : coppice * high forest * senssile oak * dendroecology * basal area increment * climate change * emission scenarios Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 3.064, year: 2016

  18. Storm intensity and old-growth forest disturbances in the Amazon region

    Science.gov (United States)

    F.D.B. Espírito-Santo; M. Keller; B. Braswell; B.W. Nelson; S. Frolking; G. Vicente

    2010-01-01

    We analyzed the pattern of large forest disturbances or blow‐downs apparently caused by severe storms in a mostly unmanaged portion of the Brazilian Amazon using 27 Landsat images and daily precipitation estimates from NOAA satellite data. For each Landsat a spectral mixture analysis (SMA) was applied. Based on SMA, we detected and mapped 279 patches (from 5 ha to 2,...

  19. Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.

    Science.gov (United States)

    Liu, Ting-Wu; Wu, Fei-Hua; Wang, Wen-Hua; Chen, Juan; Li, Zhen-Ji; Dong, Xue-Jun; Patton, Janet; Pei, Zhen-Ming; Zheng, Hai-Lei

    2011-04-01

    We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR × Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil.

  20. Stand structure and climate influence on the growth trends of a marginal forest population of Pinus nigra spp. nigra

    Directory of Open Access Journals (Sweden)

    Maurizio Marchi

    2015-12-01

    Full Text Available The Black pine of Villetta Barrea (Pinus nigra ssp. nigra var italica is a variety of the nigra subspecies. It is naturally distributed only in the Abruzzo Region, near the village of Villetta Barrea, with a rear-edge marginal population.  A dendrochronological sampling of the population was implemented with the aim of studying its stand structure and the most probable interactions between growth trends and climate. Mensurational data were used to characterize the stand and, furthermore, the general correlation function (CF and the moving correlation function (MCF, with a 30 years window, were used to assess the interrelation between the growth of the tree rings and the climate.The results indicated that the past forest management, mainly carried out with thinnings from below and selective cuttings, influenced the current structure of the forest (mean diameter but no differences in growth trends were detected within the population.The survey on Villetta Barrea Black pine showed a positive and statistically significant correlation between the ring-width and the average temperatures of the months of December (before the ring formation - t-1, February and March; but it also showed a negative correlation with the temperatures of July, September and October of the current year (t.Moreover, the analysis with moving correlation functions suggested that, in the last decades, the population has negatively reacted to very few climate factors and, in particular, to the changes in temperatures (both minimum and maximum temperatures. This is especially true for the shifts occurred in September, the year of the ring formation.

  1. Long-lasting effects of land use history on soil fungal communities in second-growth tropical rain forests.

    Science.gov (United States)

    Bachelot, Benedicte; Uriarte, María; Zimmerman, Jess K; Thompson, Jill; Leff, Jonathan W; Asiaii, Ava; Koshner, Jenny; McGuire, Krista

    2016-09-01

    Our understanding of the long-lasting effects of human land use on soil fungal communities in tropical forests is limited. Yet, over 70% of all remaining tropical forests are growing in former agricultural or logged areas. We investigated the relationship among land use history, biotic and abiotic factors, and soil fungal community composition and diversity in a second-growth tropical forest in Puerto Rico. We coupled high-throughput DNA sequencing with tree community and environmental data to determine whether land use history had an effect on soil fungal community descriptors. We also investigated the biotic and abiotic factors that underlie such differences and asked whether the relative importance of biotic (tree diversity, basal tree area, and litterfall biomass) and abiotic (soil type, pH, iron, and total carbon, water flow, and canopy openness) factors in structuring soil fungal communities differed according to land use history. We demonstrated long-lasting effects of land use history on soil fungal communities. At our research site, most of the explained variation in soil fungal composition (R 2  = 18.6%), richness (R 2  = 11.4%), and evenness (R 2  = 10%) was associated with edaphic factors. Areas previously subject to both logging and farming had a soil fungal community with lower beta diversity and greater evenness of fungal operational taxonomic units (OTUs) than areas subject to light logging. Yet, fungal richness was similar between the two areas of historical land use. Together, these results suggest that fungal communities in disturbed areas are more homogeneous and diverse than in areas subject to light logging. Edaphic factors were the most strongly correlated with soil fungal composition, especially in areas subject to light logging, where soils are more heterogenous. High functional tree diversity in areas subject to both logging and farming led to stronger correlations between biotic factors and fungal composition than in areas subject

  2. Associations between heterozygosity and growth rate variables in three western forest trees

    Science.gov (United States)

    Jeffry B. Milton; Peggy Knowles; Kareen B. Sturgeon; Yan B. Linhart; Martha Davis

    1981-01-01

    For each of three species, quaking aspen, ponderosa pine, and lodgepole pine, we determined the relationships between a ranking of heterozygosity of individuals and measures of growth rate. Genetic variation was assayed by starch gel electrophoresis of enzymes. Growth rates were characterized by the mean, standard deviation, logarithm of the variance, and coefficient...

  3. Climate is a stronger driver of tree and forest growth rates than soil and disturbance

    NARCIS (Netherlands)

    Toledo, M.; Poorter, L.; Peña-Claros, M.; Alarcón, A.; Balcázar, J.; Leaño, C.; Licona, J.C.; Llanque, O.; Vroomans, V.; Zuidema, P.; Bongers, F.

    2011-01-01

    1. Essential resources such as water, nutrients and light vary over space and time and plant growth rates are expected to vary accordingly. We examined the effects of climate, soil and logging disturbances on diameter growth rates at the tree and stand level, using 165 1-ha permanent sample plots

  4. Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches.

    Science.gov (United States)

    Wagner, Elena L E S; Roche, Dominique G; Binning, Sandra A; Wismer, Sharon; Bshary, Redouan

    2015-01-01

    Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes), live coral cover and patch size (volume). The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus, was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region.

  5. Temporal comparison and predictors of fish species abundance and richness on undisturbed coral reef patches

    Directory of Open Access Journals (Sweden)

    Elena L.E.S. Wagner

    2015-12-01

    Full Text Available Large disturbances can cause rapid degradation of coral reef communities, but what baseline changes in species assemblages occur on undisturbed reefs through time? We surveyed live coral cover, reef fish abundance and fish species richness in 1997 and again in 2007 on 47 fringing patch reefs of varying size and depth at Mersa Bareika, Ras Mohammed National Park, Egypt. No major human or natural disturbance event occurred between these two survey periods in this remote protected area. In the absence of large disturbances, we found that live coral cover, reef fish abundance and fish species richness did not differ in 1997 compared to 2007. Fish abundance and species richness on patches was largely related to the presence of shelters (caves and/or holes, live coral cover and patch size (volume. The presence of the ectoparasite-eating cleaner wrasse, Labroides dimidiatus, was also positively related to fish species richness. Our results underscore the importance of physical reef characteristics, such as patch size and shelter availability, in addition to biotic characteristics, such as live coral cover and cleaner wrasse abundance, in supporting reef fish species richness and abundance through time in a relatively undisturbed and understudied region.

  6. Studies on technology for seaweed forest construction and transplanted Ecklonia cava growth for an artificial seaweed reef.

    Science.gov (United States)

    Kim, Young-Dae; Hong, Jung-Pyo; Song, Hong-Ln; Park, Mi Seon; Moon, Tae Suk; Yoo, Hyun Il

    2012-09-01

    We installed seaweed reef for restoration of barron ground coast. We hollowed out a U-shaped groove in a cross-shaped artificial seaweed reef and covered it with a zinc sheet (U-bar) to transplant Ecklonia cava growing on Dellenia wood by hand, installing the U-bar on the artificial seaweed reef, fixing it with concrete. Thus seaweed can be attached easily, with pre-installed stainless bolts and nuts. The length of Ecklonia cava leaf transplanted to the cross-shaped reef was 7.2 cm in February 2005 reached its maximum size, 35.9 cm (n = 30) by July. Thereafter, it decreased to 18.9 cm in October due to shedding. The leaf weight after the experiment was 24.8 from the initial 0.4 cm (n = 30). Regression analysis showed Y = 0.7875X-4.6488 (R2 = 0.7225) for blade length and Y = 0.0025X2.6733 (R2 = 0.8711) for leaf weight. The high values of the R2 values for the two measurements were highly reliable, with the reliability of the linear regression function higher than that of the functions of 2 variables. The artificial seaweed forest constructed in the barren ground was highly comparable with natural seaweed forest in terms of growth, indicating that the artificial seaweed construction can be done in an easy, efficient and economically viable way. This further indicates that the technology developed by the present study can be extensively used for the project for artificial seaweed forest construction.

  7. Floristic and structural status of forests in permanent preservation areas of Moju river basin, Amazon region.

    Science.gov (United States)

    Oliveira, J C; Vieira, I C G; Almeida, A S; Silva, C A

    2016-01-01

    The goal of this study is to analyze the floristic patterns and the structure of disturbed and undisturbed upland forests, in Permanent Preservation Areas (PPAs) along the Moju river, in the Brazilian state of Pará. Trees with a diameter equal to or larger than 10cm at 1.30m from the ground (DBH) ≥10cm were analyzed for the upper stratum. For the middle stratum, individuals with DBH between 4.99 and 9.99cm were sampled. Forty-five families and 221 species were found in disturbed forests, and 43 families and 208 species in undisturbed forests. Floristic similarity was high between strata and between forest types, with values above 50%. Similarity was highest between middle strata. The most species-abundant families in undisturbed forests were Fabaceae, Sapotaceae, Chrysobalanaceae and Myrtaceae; the species with the highest density there were Eschweilera grandiflora, Licania sclerophylla and Zygia cauliflora. In disturbed forests, the dominant families were Fabaceae, Sapotaceae, Lecythidaceae and Melastomataceae. The Shannon-Wiener diversity index was 3.21 for undisturbed forests and 2.85 for disturbed forests. Non-metric multidimensional scaling (MDS) analysis did not group the forests by their floristic composition in both upper and middle strata. Overall, the PPA forests along the Moju river, even if disturbed, did not show major floristic changes but substantially change their structural characteristics.

  8. Floristic and structural status of forests in permanent preservation areas of Moju river basin, Amazon region

    Directory of Open Access Journals (Sweden)

    J. C. Oliveira

    Full Text Available Abstract The goal of this study is to analyze the floristic patterns and the structure of disturbed and undisturbed upland forests, in Permanent Preservation Areas (PPAs along the Moju river, in the Brazilian state of Pará. Trees with a diameter equal to or larger than 10cm at 1.30m from the ground (DBH ≥10cm were analyzed for the upper stratum. For the middle stratum, individuals with DBH between 4.99 and 9.99cm were sampled. Forty-five families and 221 species were found in disturbed forests, and 43 families and 208 species in undisturbed forests. Floristic similarity was high between strata and between forest types, with values above 50%. Similarity was highest between middle strata. The most species-abundant families in undisturbed forests were Fabaceae, Sapotaceae, Chrysobalanaceae and Myrtaceae; the species with the highest density there were Eschweilera grandiflora, Licania sclerophylla and Zygia cauliflora. In disturbed forests, the dominant families were Fabaceae, Sapotaceae, Lecythidaceae and Melastomataceae. The Shannon-Wiener diversity index was 3.21 for undisturbed forests and 2.85 for disturbed forests. Non-metric multidimensional scaling (MDS analysis did not group the forests by their floristic composition in both upper and middle strata. Overall, the PPA forests along the Moju river, even if disturbed, did not show major floristic changes but substantially change their structural characteristics.

  9. Mating system, population growth, and management scenario for Kalanchoe pinnata in an invaded seasonally dry tropical forest.

    Science.gov (United States)

    González de León, Salvador; Herrera, Ileana; Guevara, Roger

    2016-07-01

    Ecological invasions are a major issue worldwide, where successful invasion depends on traits that facilitate dispersion, establishment, and population growth. The nonnative succulent plant Kalanchoe pinnata, reported as invasive in some countries, is widespread in remnants of seasonally dry tropical forest on a volcanic outcrop with high conservation value in east-central Mexico where we assessed its mating system and demographic growth and identified management strategies. To understand its local mating system, we conducted hand-pollination treatments, germination, and survival experiments. Based on the experimental data, we constructed a life-stage population matrix, identified the key traits for population growth, weighted the contributions of vegetative and sexual reproduction, and evaluated management scenarios. Hand-pollination treatments had slight effects on fruit and seed setting, as well as on germination. With natural pollination treatment, the successful germination of seeds from only 2/39 fruit suggests occasional effective natural cross-pollination. The ratios of the metrics for self- and cross-pollinated flowers suggest that K. pinnata is partially self-compatible. Most of the pollinated flowers developed into fruit, but the seed germination and seedling survival rates were low. Thus, vegetative propagation and juvenile survival are the main drivers of population growth. Simulations of a virtual K. pinnata population suggest that an intense and sustained weeding campaign will reduce the population within at least 10 years. Synthesis and applications. The study population is partially self-compatible, but sexual reproduction by K. pinnata is limited at the study site, and population growth is supported by vegetative propagation and juvenile survival. Demographic modeling provides key insights and realistic forecasts on invasion process and therefore is useful to design management strategies.

  10. [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.

  11. Water balances of old-growth and regenerating montane cloud forests in central Veracruz, Mexico

    Science.gov (United States)

    Muñoz-Villers, L. E.; Holwerda, F.; Gómez-Cárdenas, M.; Equihua, M.; Asbjornsen, H.; Bruijnzeel, L. A.; Marín-Castro, B. E.; Tobón, C.

    2012-09-01

    SummaryThis paper compares the water budgets of two adjacent micro-catchments covered by mature (MAT) and 20-year-old secondary (SEC) lower montane cloud forests, respectively, in central Veracruz, Mexico over a 2-year period. Rainfall (P) and streamflow (Q) were measured continuously, whereas dry canopy evaporation (transpiration Et), wet canopy evaporation (rainfall interception I), and cloud water interception (CWI) were quantified using a combination of field measurements and modeling. Mean annual P was 3467 mm, of which typically 80% fell during the wet season (May-October). Fog interception occurred exclusively during the dry season (November-April), and was ⩽2% of annual P for both forests. Rainfall interception loss was dominated by post-event evaporation of intercepted water rather than by within-event evaporation. Therefore, the higher overall I (i.e. including CWI) by the MAT (16% of P vs. 8% for the SEC) reflects a higher canopy storage capacity, related in turn to higher leaf area index and greater epiphyte biomass. Annual Et totals derived from sapflow measurements were nearly equal for the MAT and SEC (˜790 mm each). Total annual water yield calculated as P minus (Et + I) was somewhat higher for the SEC (2441 mm) than for the MAT (2077 mm), and mainly reflects the difference in I. Mean annual Q was also higher for the SEC (1527 mm) than for the MAT (1338 mm), and consisted mostly of baseflow (˜90%). Baseflow recession rates were nearly equal between the two forests, as were stormflow coefficients (4% and 5% for MAT and SEC, respectively). The very low runoff response to rainfall is attributed to the high infiltration and water retention capacities of the volcanic soils throughout the ˜2 m deep profile. The water budget results indicate that ˜875 and 700 mm year-1 leave the SEC and MAT as deep groundwater leakage, which is considered plausible given the fractured geology in the study area. It is concluded that 20 years of natural regeneration

  12. Survival, growth and reproduction by big-leaf mahogany (Swietenia macrophylla) in open clearing vs. forested conditions in Brazil

    Science.gov (United States)

    James Grogan; Mark Schulze; Jurandir Galvao

    2010-01-01

    Big-leaf mahogany (Swietenia macrophylla) trees are often retained in agricultural fields and pastures for seed and timber production after selective logging and forest clearing in the Brazilian Amazon. At a forest management site in southeast Para´, we censused trees growing scattered across a large open clearing after forest removal and in heavily disturbed forest...

  13. Some factors that will affect the next generation of forest growth models

    International Nuclear Information System (INIS)

    Leary, R.A.

    1988-01-01

    This paper discusses several types of factors that affect the form and referents of future growth models. These include philosophical, scientific, technological, educational, and organizational factors. Each factor is presented individually

  14. Accuracy and equivalence testing of crown ratio models and assessment of their impact on diameter growth and basal area increment predictions of two variants of the Forest Vegetation Simulator

    Science.gov (United States)

    Laura P. Leites; Andrew P. Robinson; Nicholas L. Crookston

    2009-01-01

    Diameter growth (DG) equations in many existing forest growth and yield models use tree crown ratio (CR) as a predictor variable. Where CR is not measured, it is estimated from other measured variables. We evaluated CR estimation accuracy for the models in two Forest Vegetation Simulator variants: the exponential and the logistic CR models used in the North...

  15. Carbon uptake, growth and resource-use efficiency in one invasive and six native Hawaiian dry forest tree species.

    Science.gov (United States)

    Stratton, L C; Goldstein, G

    2001-12-01

    Photosynthetic gas exchange, nitrogen- and water-use efficiency, leaf water potential and seasonal patterns of leaf production were studied in seven, dominant dry-forest species from the island of Lana'i, Hawaii, including the rapidly colonizing, non-native Schinus terebinthifolius (Raddi). We evaluated whether unique physiological characteristics of the invasive species explain its capacity to rapidly invade dry forests throughout the Hawaiian Islands. Apparent anomalies in stable carbon isotope data (delta13C) relative to other results led us to study effects of environmental conditions and physiological performance during leaf expansion on delta13C. Species that expanded all their foliage at the beginning of the wet season had more negative leaf delta13C values during the dry season than species with continuous leaf expansion. Among species, S. terebinthifolius had a strong seasonal pattern of leaf production and the most negative delta13C (-29 per thousand). With respect to almost every trait measured, S. terebinthifolius fell at an end of the range of values for the native species. Rapid growth of S. terebinthifolius in this ecosystem may be partially explained by its high maximum CO2 assimilation rates (15 micromol m-2 s-1), low leaf mass per area, high photosynthetic nitrogen-use efficiency per unit leaf mass or area and large decrease in stomatal conductance during the dry season. Relative to the native species, the invasive species exhibited striking phenotypic plasticity, including high rates of stem growth and water and CO2 uptake during the wet season, and maintenance of leaves and high leaf water potentials, as a result of reduced water loss, during the dry season, enabling it to utilize available resources effectively.

  16. Restoration of Degraded Soil in the Nanmangalam Reserve Forest with Native Tree Species: Effect of Indigenous Plant Growth-Promoting Bacteria

    Directory of Open Access Journals (Sweden)

    Andimuthu Ramachandran

    2016-01-01

    Full Text Available Restoration of a highly degraded forest, which had lost its natural capacity for regeneration, was attempted in the Nanmangalam Reserve Forest in Eastern Ghats of India. In field experiment, 12 native tree species were planted. The restoration included inoculation with a consortium of 5 native plant growth-promoting bacteria (PGPB, with the addition of small amounts of compost and a chemical fertilizer (NPK. The experimental fields were maintained for 1080 days. The growth and biomass varied depending on the plant species. All native plants responded well to the supplementation with the native PGPB. The plants such as Pongamia pinnata, Tamarindus indica, Gmelina arborea, Wrightia tinctoria, Syzygium cumini, Albizia lebbeck, Terminalia bellirica, and Azadirachta indica performed well in the native soil. This study demonstrated, by using native trees and PGPB, a possibility to restore the degraded forest.

  17. Implications of rural-urban migration for conservation of the Atlantic Forest and urban growth in Misiones, Argentina (1970-2030).

    Science.gov (United States)

    Izquierdo, Andrea E; Grau, Héctor R; Aide, T Mitchell

    2011-05-01

    Global trends of increasing rural-urban migration and population urbanization could provide opportunities for nature conservation, particularly in regions where deforestation is driven by subsistence agriculture. We analyzed the role of rural population as a driver of deforestation and its contribution to urban population growth from 1970 to the present in the Atlantic Forest of Argentina, a global conservation priority. We created future land-use-cover scenarios based on human demographic parameters and the relationship between rural population and land-cover change between 1970 and 2006. In 2006, native forest covered 50% of the province, but by 2030 all scenarios predicted a decrease that ranged from 18 to 39% forest cover. Between 1970 and 2001, rural migrants represented 20% of urban population growth and are expected to represent less than 10% by 2030. This modeling approach shows how rural-urban migration and land-use planning can favor nature conservation with little impact on urban areas.

  18. Status of the undisturbed mangroves at Brunei Bay, East Malaysia: a preliminary assessment based on remote sensing and ground-truth observations

    Science.gov (United States)

    Izzaty Horsali, Nurul Amira; Mat Zauki, Nurul Ashikin; Otero, Viviana; Nadzri, Muhammad Izuan; Ibrahim, Sulong; Husain, Mohd-Lokman; Dahdouh-Guebas, Farid

    2018-01-01

    Brunei Bay, which receives freshwater discharge from four major rivers, namely Limbang, Sundar, Weston and Menumbok, hosts a luxuriant mangrove cover in East Malaysia. However, this relatively undisturbed mangrove forest has been less scientifically explored, especially in terms of vegetation structure, ecosystem services and functioning, and land-use/cover changes. In the present study, mangrove areal extent together with species composition and distribution at the four notified estuaries was evaluated through remote sensing (Advanced Land Observation Satellite—ALOS) and ground-truth (Point-Centred Quarter Method—PCQM) observations. As of 2010, the total mangrove cover was found to be ca. 35,183.74 ha, of which Weston and Menumbok occupied more than two-folds (58%), followed by Sundar (27%) and Limbang (15%). The medium resolution ALOS data were efficient for mapping dominant mangrove species such as Nypa fruticans, Rhizophora apiculata, Sonneratia caseolaris, S. alba and Xylocarpus granatum in the vicinity (accuracy: 80%). The PCQM estimates found a higher basal area at Limbang and Menumbok—suggestive of more mature vegetation, compared to Sundar and Weston. Mangrove stand structural complexity (derived from the complexity index) was also high in the order of Limbang > Menumbok > Sundar > Weston and supporting the perspective of less/undisturbed vegetation at two former locations. Both remote sensing and ground-truth observations have complementarily represented the distribution of Sonneratia spp. as pioneer vegetation at shallow river mouths, N. fruticans in the areas of strong freshwater discharge, R. apiculata in the areas of strong neritic incursion and X. granatum at interior/elevated grounds. The results from this study would be able to serve as strong baseline data for future mangrove investigations at Brunei Bay, including for monitoring and management purposes locally at present. PMID:29479500

  19. Status of the undisturbed mangroves at Brunei Bay, East Malaysia: a preliminary assessment based on remote sensing and ground-truth observations

    Directory of Open Access Journals (Sweden)

    Behara Satyanarayana

    2018-02-01

    Full Text Available Brunei Bay, which receives freshwater discharge from four major rivers, namely Limbang, Sundar, Weston and Menumbok, hosts a luxuriant mangrove cover in East Malaysia. However, this relatively undisturbed mangrove forest has been less scientifically explored, especially in terms of vegetation structure, ecosystem services and functioning, and land-use/cover changes. In the present study, mangrove areal extent together with species composition and distribution at the four notified estuaries was evaluated through remote sensing (Advanced Land Observation Satellite—ALOS and ground-truth (Point-Centred Quarter Method—PCQM observations. As of 2010, the total mangrove cover was found to be ca. 35,183.74 ha, of which Weston and Menumbok occupied more than two-folds (58%, followed by Sundar (27% and Limbang (15%. The medium resolution ALOS data were efficient for mapping dominant mangrove species such as Nypa fruticans, Rhizophora apiculata, Sonneratia caseolaris, S. alba and Xylocarpus granatum in the vicinity (accuracy: 80%. The PCQM estimates found a higher basal area at Limbang and Menumbok—suggestive of more mature vegetation, compared to Sundar and Weston. Mangrove stand structural complexity (derived from the complexity index was also high in the order of Limbang > Menumbok > Sundar > Weston and supporting the perspective of less/undisturbed vegetation at two former locations. Both remote sensing and ground-truth observations have complementarily represented the distribution of Sonneratia spp. as pioneer vegetation at shallow river mouths, N. fruticans in the areas of strong freshwater discharge, R. apiculata in the areas of strong neritic incursion and X. granatum at interior/elevated grounds. The results from this study would be able to serve as strong baseline data for future mangrove investigations at Brunei Bay, including for monitoring and management purposes locally at present.

  20. Iowa's forest resources, 1974.

    Science.gov (United States)

    John S. Jr. Spencer; Pamela J. Jakes

    1980-01-01

    The second inventory of Iowa's forest resources shows big declines in commercial forest area and in growing-stock and sawtimber volumes between 1954 and 1974. Presented are text and statistics on forest area and timber volume, growth, mortality, ownership, stocking, future timber supply, timber use, forest management opportunities, and nontimber resources.

  1. Impact of Forest Harvesting and Forest Regeneration on Runoff Dynamics at Watersheds of Central Siberia

    Directory of Open Access Journals (Sweden)

    A. A. Onuchin

    2014-02-01

    Full Text Available In the paper disturbance of Angara river region forests were estimated and peculiarities of forest regeneration after logging and wild fires were analyzed. According to the landscape classification of the regional study, three groups of landscapes differencing on types of forest successions were developed. It was shown that water protective and water regulate functions of the Angara river region forests change under commercial forest harvesting. Comparisons of the inventory and hydrological data detected that hydrological consequences of commercial forest harvesting are dependent on climatic parameters and forest regeneration peculiarities. In the continental climate conditions, when forest regeneration is delayed, snow storms are more active, snow evaporation increases and runoff reduces. In the process of logging sites overgrown with secondary small-leaved forest, snow accumulation increases and runoff increases, exceeding the value of annual runoff at undisturbed watersheds.

  2. Cross-scale interactions affect tree growth and intrinsic water use efficiency and highlight the importance of spatial context in managing forests under global change

    Science.gov (United States)

    Kenneth J. Ruzicka; Klaus J. Puettmann; J. Renée Brooks

    2017-01-01

    Summary1. We investigated the potential of cross-scale interactions to affect the outcome of density reduction in a large-scale silvicultural experiment to better understand options for managing forests under climate change. 2. We measured tree growth and intrinsic water-use efficiency (iWUE) based on stable carbon isotopes (δ...

  3. Forest growth along a rainfall gradient in Hawaii: Acacia koa stand structure, productivity, foliar nutrients, and water- and nutrient-use efficiencies

    Science.gov (United States)

    Robin A. Harrington; James H. Fownes; Frederick C. Meinzer; Paul G. Scowcroft

    1995-01-01

    We tested whether variation in growth of native koa (Acacia koa) forest along a rainfall gradient was attributable to differences in leaf area index (LAI) or to differences in physiological performance per unit of leaf area. Koa stands were studied on western Kauai prior to Hurricane Iniki, and ranged from 500 to 1130 m elevation and from 850 to...

  4. Draft genome sequence of Burkholderia sordidicola S170, a potential plant growth promoter isolated from coniferous forest soil in the Czech Republic

    DEFF Research Database (Denmark)

    Lladó, Salvador; Xu, Zhuofei; Sørensen, Søren Johannes

    2014-01-01

    Burkholderia species are key players in the accumulation of carbon from cellulose decomposition in coniferous forest ecosystems. We report here the draft genome of Burkholderia sordidicola strain S170, containing features associated with known genes involved in plant growth promotion, the biologi...

  5. Effect of gap size on seedling establishment, growth and survival at three years in mountain ash (Eucalyptus regnans F. Muell.) forest in Victoria, Australia

    NARCIS (Netherlands)

    Meer, van der P.J.; Dignan, P.; Saveneh, A.G.

    1999-01-01

    Establishment, growth and survival of Eucalyptus regnans F. Muell. seedlings was studied at two sites over three years under a range of small gaps (up to 30mx30m) and large gaps (50mx50m up to clearfells) in a gap cutting experiment in mountain ash forest at Tanjil Bren, Victoria, Australia. In both

  6. Additions to the Flora of Cleveland County, Arkansas: Collections From Moro Bottoms Natural Area, A State-Protected Old-Growth Bottomland Hardwood Forest

    Science.gov (United States)

    Danny Skojac; Margaret S. Devall; Bernard R. Parresol

    2003-01-01

    An annotated list of 38 additions to the vascular flora of Cleveland County, Arkansas is presented. The additions presented were collected from Moro Bottoms Natural Area, a state-protected old-growth bottomland hardwood forest located in the northwest region of the county.

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

    Science.gov (United States)

    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...

  8. Growth and mortality patterns in a thinning canopy of post-hurricane regenerating rain forest in eastern Nicaragua (1990-2005

    Directory of Open Access Journals (Sweden)

    Javier Ruiz

    2010-12-01

    Full Text Available One of the strongest hypothesis about the maintenance of tree species diversity in tropical areas is disturbance. In order to assess this, the effect of intensive natural disturbances on forest growth and mortality in a thinning canopy was studied after the landfall of hurricane Joan in 1988. We evaluated the growth and mortality rates of the 26 most common tree species of that forest in eastern Nicaragua. Permanent plots were established at two study sites within the damaged area. Growth and mortality rates of all individual trees ≥3.18cm diameter at breast height were assessed annually from 1990 to 2005. During this period the forest underwent two phases: the building phase (marked by increased number of individuals of tree species present after the hurricane and the canopy thinning phase (marked by increased competition and mortality. Our results from the thinning phase show that tree survival was independent of species identity and was positively related to the increase in growth rates. The analysis of mortality presented here aims to test the null hypothesis that individual trees die independently of their species identity. These findings were influenced by the mortality observed during the late thinning phase (2003-2005 and provide evidence in favor of a non-niche hypothesis at the thinning phase of forest regeneration. Rev. Biol. Trop. 58 (4: 1283-1297. Epub 2010 December 01.

  9. Impact of Sustainable Forest Management on Harvest, Growth, and Regeneration of Southern Pine in the Piedmont After 5 Years of Monitoring

    Science.gov (United States)

    Alexander Clark; James W. McMinn

    2002-01-01

    This paper describes a study established to monitor the implications of ecosystem management choices on natural loblolly and shortleaf pine stands on the Oconee National Forests in the Piedmont of Georgia. The impact of partial harvests, group selection cuts, seed tree cuts and no human disturbance on growth, mortality, species composition, and regeneration were...

  10. The effect of wood ash fertilization on soil respiration and tree stand growth in boreal peatland forests

    Science.gov (United States)

    Liimatainen, Maarit; Maljanen, Marja; Hytönen, Jyrki

    2017-04-01

    Out of Finland's original 10 million hectares of peatlands over half has been drained for forestry. Natural peatlands act as a sink for carbon but when peatland is drained, increased oxygen concentration in the peat accelerates the aerobic decomposition of the old organic matter of the peat leading to carbon dioxide (CO2) emissions to atmosphere. Increasing use of bioenergy increases also the amount of ash produced as a byproduct in power plants. Wood ash contains all essential nutrients for trees to grow except nitrogen. Therefore, wood ash is ideal fertilizer for nitrogen rich peatland forests where lack of phosphorus or potassium may restrict tree growth. At the moment, wood ash is the only available PK-fertilizer for peatland forests in Finland and areas of peatland forests fertilized with ash are increasing annually. The effects of wood ash on vegetation, soil properties and tree growth are rather well known although most of the studies have been made using fine ash whereas nowadays mostly stabilized ash (e.g. granulated) is used. Transporting and spreading of stabilized ash is easier than that of dusty fine ash. Also, slower leaching rate of nutrients is environmentally beneficial and prolongs the fertilizer effect. The knowledge on the impact of granulated wood ash on greenhouse gas emissions is still very limited. The aim of this study was to examine the effects of granulated wood ash on CO2 emissions from peat and tree stand growth. Field measurements were done in two boreal peatland forests in 2011 and 2012. One of the sites is more nutrient rich with soil carbon to nitrogen ratio (C/N) of 18 whereas the other site is nutrient poor with C/N ratio of 82. Both sites were fertilized with granulated wood ash in 2003 (5000 kg ha-1). The effect of fertilization was followed with tree stand measurements conducted 0, 5 and 10 years after the fertilization. The CO2 emissions of the decomposing peat (heterotrophic respiration) were measured from study plots where

  11. 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.

  12. Nebraska's forest resources in 2003

    Science.gov (United States)

    W. Keith Moser; Gary J. Brand; Mark H. Hansen; William R. Lovett

    2005-01-01

    Reports results of the first three yearly panels (2001-2003) of the fourth inventory of Nebraska's forest resources. Includes information on forest area; volume; biomass; growth, removals, and mortality; and forest health.

  13. Colloid and Phosphorus Leaching From Undisturbed Soil Cores Sampled Along a Natural Clay Gradient

    DEFF Research Database (Denmark)

    Vendelboe, Anders Lindblad; Møldrup, Per; Heckrath, Goswin Johann

    2011-01-01

    was to correlate easily measurable soil properties, such as clay content and water-dispersible colloids, to colloid and phosphorus leaching. The clay contents across the gradient ranged from 0.11 to 0.23 kg kgj1. Irrigating with artificial rainwater, all samples showed a high first flush of colloids and phosphorus......The presence of strongly sorbing compounds in groundwater and tile drains can be a result of colloid-facilitated transport. Colloid and phosphorus leaching from macropores in undisturbed soil cores sampled across a natural clay gradient at Aarup, Denmark, were studied. The aim of the study...... followed by lower and stable colloid and phosphorus concentrations. The mass of particles leached at first flush was independent of clay content and was attributed to the instant release of particles associated with the macropore walls and released upon contact with flowing water. Below a clay content of È...

  14. A method for measuring element fluxes in an undisturbed soil: nitrogen and carbon from earthworms

    International Nuclear Information System (INIS)

    Bouche, M.B.

    1984-01-01

    Data on chemical cycles, as nitrogen or carbon cycles, are extrapolated to the fields or ecosystems without the possibility for checking conclusions; i.e. from scientific knowledge (para-ecology). A new method, by natural introduction of an earthworm compartment into an undisturbed soil, with earthworms labelled both by isotopes ( 15 N, 14 C) and by staining is described. This method allows us to measure fluxes of chemicals. The first results, gathered during the improvement of the method in partly artificial conditions, are cross-checked with other data given by direct observation in the field. Measured flux (2.2 mg N/g fresh mass empty gut/day/15 0 C) is far more important than para-ecological estimations; animal metabolism plays directly an important role in nitrogen and carbon cycles. (author)

  15. Study of nitrogen losses at the microcosm in undisturbed soil samples subjected to thermal shocks

    Directory of Open Access Journals (Sweden)

    J. Cancelo-González

    2013-05-01

    Full Text Available Laboratory thermal shocks of different intensity and rainfall simulations were performed in undisturbed Leptic Umbrisol soil samples. Samples were collected in field using specially designed lysimeter boxes to allow sampling, thermal shocks and surface runoff and subsurface flow water collection during the rainfall simulations. Temperature was recorded during heating and degree-hours of accumulated heat were calculated and nitrogen losses in surface and subsurface water collected after two rainfall simulations were determined. Results show losses of total nitrogen from treatments 200 oC and 67 degrees-hours heat supplied in the leachate obtained after 150 mm of simulated rainfall compared with non-heat treated soils. Is remarkable that soils subjected to higher intensity heat treatments (400 oC and 278 67 degrees-hours show greater losses of N-Nitrate and N-Ammonia by subsurface flow, while this behavior was not observed in the other heat treatments.

  16. Gamma ray transmission for hydraulic conductivity measurement of undisturbed soil columns

    Directory of Open Access Journals (Sweden)

    Anderson Camargo Moreira

    2007-03-01

    Full Text Available This work had the objective to determine the Hydraulic Conductivity K(theta function for different depth levels z, of columns of undisturbed soil, using the gamma ray transmission technique applied to the Sisson method. The results indicated a growing behavior for K(theta and a homogeneous soil density, both in relation to the increase of the depth. The methodology of gamma ray transmission showed satisfactory results on the determination of the hydraulic conductivity in columns of undisturbed soil, besides being very reliable and a nondestructive method.O estudo da condutividade hidráulica para solos não saturados é essencial quando aplicado às situações relacionadas à irrigação, drenagem e transporte de nutrientes no solo, é uma importante propriedade para desenvolvimentos de culturas agrícolas. Este trabalho tem o objetivo de determinar a função Condutividade Hidráulica K(teta, em diferentes níveis z de profundidade, em colunas de solo indeformado, utilizando a transmissão de raios gama aplicada ao método de Sisson. Os resultados indicam um comportamento crescente para K(teta e uma densidade de solo homogênea, ambos em relação ao aumento da profundidade. A metodologia de transmissão de raios gama mostrou resultados bastante satisfatórios na determinação da condutividade hidráulica em colunas de solo indeformado, além de ser muito confiável e não destrutivo.

  17. The water balance components of undisturbed tropical woodlands in the Brazilian cerrado

    Science.gov (United States)

    Oliveira, P. T. S.; Wendland, E.; Nearing, M. A.; Scott, R. L.; Rosolem, R.; da Rocha, H. R.

    2015-06-01

    Deforestation of the Brazilian cerrado region has caused major changes in hydrological processes. These changes in water balance components are still poorly understood but are important for making land management decisions in this region. To better understand pre-deforestation conditions, we determined the main components of the water balance for an undisturbed tropical woodland classified as "cerrado sensu stricto denso". We developed an empirical model to estimate actual evapotranspiration (ET) by using flux tower measurements and vegetation conditions inferred from the enhanced vegetation index and reference evapotranspiration. Canopy interception, throughfall, stemflow, surface runoff, and water table level were assessed from ground measurements. We used data from two cerrado sites, Pé de Gigante (PDG) and Instituto Arruda Botelho (IAB). Flux tower data from the PDG site collected from 2001 to 2003 were used to develop the empirical model to estimate ET. The other hydrological processes were measured at the field scale between 2011 and 2014 at the IAB site. The empirical model showed significant agreement (R2 = 0.73) with observed ET at the daily timescale. The average values of estimated ET at the IAB site ranged from 1.91 to 2.60 mm day-1 for the dry and wet seasons, respectively. Canopy interception ranged from 4 to 20 % and stemflow values were approximately 1 % of the gross precipitation. The average runoff coefficient was less than 1 %, while cerrado deforestation has the potential to increase that amount up to 20-fold. As relatively little excess water runs off (either by surface water or groundwater), the water storage may be estimated by the difference between precipitation and evapotranspiration. Our results provide benchmark values of water balance dynamics in the undisturbed cerrado that will be useful to evaluate past and future land-cover and land-use changes for this region.

  18. Continuous arterial PO2 profiles in unrestrained, undisturbed aquatic turtles during routine behaviors.

    Science.gov (United States)

    Williams, Cassondra L; Hicks, James W

    2016-11-15

    Mammals and birds maintain high arterial partial pressure of oxygen (P O 2 ) values in order to preserve near-complete hemoglobin (Hb) oxygen (O 2 ) saturation. In diving mammals and birds, arterial O 2 follows a primarily monotonic decline and then recovers quickly after dives. In laboratory studies of submerged freshwater turtles, arterial O 2 depletion typically follows a similar pattern. However, in these studies, turtles were disturbed, frequently tethered to external equipment and confined either to small tanks or breathing holes. Aquatic turtles can alter cardiac shunting patterns, which will affect arterial P O 2  values. Consequently, little is known about arterial O 2 regulation and use in undisturbed turtles. We conducted the first study to continuously measure arterial P O 2  using implanted microelectrodes and a backpack logger in undisturbed red-eared sliders during routine activities. Arterial P O 2  profiles during submergences varied dramatically, with no consistent patterns. Arterial P O 2  was also lower than previously reported during all activities, with values rarely above 50 mmHg (85% Hb saturation). There was no difference in mean P O 2  between five different activities: submerged resting, swimming, basking, resting at the surface and when a person was present. These results suggest significant cardiac shunting occurs during routine activities as well as submergences. However, the lack of relationship between P O 2  and any activity suggests that cardiac shunts are not regulated to maintain high arterial P O 2  values. These data support the idea that cardiac shunting is the passive by-product of regulation of vascular resistances by the autonomic nervous system. © 2016. Published by The Company of Biologists Ltd.

  19. Continuous arterial PO2 profiles in unrestrained, undisturbed aquatic turtles during routine behaviors

    Science.gov (United States)

    Hicks, James W.

    2016-01-01

    ABSTRACT Mammals and birds maintain high arterial partial pressure of oxygen (PO2) values in order to preserve near-complete hemoglobin (Hb) oxygen (O2) saturation. In diving mammals and birds, arterial O2 follows a primarily monotonic decline and then recovers quickly after dives. In laboratory studies of submerged freshwater turtles, arterial O2 depletion typically follows a similar pattern. However, in these studies, turtles were disturbed, frequently tethered to external equipment and confined either to small tanks or breathing holes. Aquatic turtles can alter cardiac shunting patterns, which will affect arterial PO2 values. Consequently, little is known about arterial O2 regulation and use in undisturbed turtles. We conducted the first study to continuously measure arterial PO2 using implanted microelectrodes and a backpack logger in undisturbed red-eared sliders during routine activities. Arterial PO2 profiles during submergences varied dramatically, with no consistent patterns. Arterial PO2 was also lower than previously reported during all activities, with values rarely above 50 mmHg (85% Hb saturation). There was no difference in mean PO2 between five different activities: submerged resting, swimming, basking, resting at the surface and when a person was present. These results suggest significant cardiac shunting occurs during routine activities as well as submergences. However, the lack of relationship between PO2 and any activity suggests that cardiac shunts are not regulated to maintain high arterial PO2 values. These data support the idea that cardiac shunting is the passive by-product of regulation of vascular resistances by the autonomic nervous system. PMID:27618860

  20. Modeling transcriptional networks regulating secondary growth and wood formation in forest trees

    Science.gov (United States)

    Lijun Liu; Vladimir Filkov; Andrew Groover

    2013-01-01

    The complex interactions among the genes that underlie a biological process can be modeled and presented as a transcriptional network, in which genes (nodes) and their interactions (edges) are shown in a graphical form similar to a wiring diagram. A large number of genes have been identified that are expressed during the radial woody growth of tree stems (secondary...

  1. A first-approximation simple dynamic growth model for forest teak ...

    African Journals Online (AJOL)

    A biologically consistent whole-stand growth model is presented, which uses the state-space approach for modelling rates of change of dominant height, stand density and stand basal area. A simple model containing few free parameters performed well and is particularly well suited to situations where available data are ...

  2. Proteomic Analyses Provide Novel Insights into Plant Growth and Ginsenoside Biosynthesis in Forest Cultivated Panax ginseng (F. Ginseng)

    Science.gov (United States)

    Ma, Rui; Sun, Liwei; Chen, Xuenan; Mei, Bing; Chang, Guijuan; Wang, Manying; Zhao, Daqing

    2016-01-01

    F. Ginseng (Panax ginseng) is planted in the forest to enhance the natural ginseng resources, which have an immense medicinal and economic value. The morphology of the cultivated plants becomes similar to that of wild growing ginseng (W. Ginseng) over the years. So far, there have been no studies highlighting the physiological or functional changes in F. Ginseng and its wild counterparts. In the present study, we used proteomic technologies (2DE and iTRAQ) coupled to mass spectrometry to compare W. Ginseng and F. Ginseng at various growth stages. Hierarchical cluster analysis based on protein abundance revealed that the protein expression profile of 25-year-old F. Ginseng was more like W. Ginseng than less 20-year-old F. Ginseng. We identified 192 differentially expressed protein spots in F. Ginseng. These protein spots increased with increase in growth years of F. Ginseng and were associated with proteins involved in energy metabolism, ginsenosides biosynthesis, and stress response. The mRNA, physiological, and metabolic analysis showed that the external morphology, protein expression profile, and ginsenoside synthesis ability of the F. Ginseng increased just like that of W. Ginseng with the increase in age. Our study represents the first characterization of the proteome of F. Ginseng during development and provides new insights into the metabolism and accumulation of ginsenosides. PMID:26858731

  3. Reproduction and vegetative growth in the dioecious shrub Acer barbinerve in temperate forests of Northeast China.

    Science.gov (United States)

    Wang, Juan; Zhang, Chunyu; Gadow, Klaus V; Cheng, Yanxia; Zhao, Xiuhai

    2015-06-01

    Trade-off in dioecious plant. The trade-off between reproduction, vegetative growth and maintenance is a major issue in the life history of an organism and a record of the process which is producing the largest possible number of living offspring by natural selection. Dioecious species afford an excellent opportunity for detecting such possible trade-offs in resource allocation. In this study, we selected the dioecious shrub Acer barbinerve to examine possible trade-offs between reproduction and vegetative growth in both genders at different modular levels during three successive years. Reproductive and vegetative biomass values were assessed during successive years to evaluate their intra-annual and inter-annual trade-offs. These trade-offs were examined at shoot, branch and shrub modular levels in Acer barbinerve shrubs. An intra-annual trade-off was detected at the shoot level for both genders in 2011 and 2012. Both males and females showed a negative correlation between reproduction and vegetative growth, but this was more prominent in males. For the females of the species, inter-annual trade-offs were only found at branch and shrub levels. Slightly negative correlations in females were detected between the reproduction in 2012 and the reproduction in the two previous years. The gender ratio was significantly male biased during the three successive years of our investigation. Females had higher mortality rates in the larger diameter classes, both in 2011 and 2012. This study revealed a clear trade-off between reproduction and vegetative growth in Acer barbinerve, but results varied between males and females. The degree of autonomy of the different modular levels may affect the ability to detect such trade-offs.

  4. Ground level ozone effects in individual growth phases of central european submountain beech forests

    Directory of Open Access Journals (Sweden)

    Kellerová Daniela

    2014-03-01

    Full Text Available We observed ground level ozone concentrations on a series of five beech experimental plots, one representing the original stand and the other four generated and modified by cuts of graduated intensity. The study was carried out in a beech ecosystem in the Kremnické vrchy Mts, the Western Carpathian region, in years 1999-2008. The plots, established in 1989, were evaluated and compared statistically before and after the cutting modification in 2004. The level of significance of the effect of this intervention was 99% on the plot representing small-area clear-cut and on the plot treated with medium cut. Differences, though not significant, were also found in the other plots. Apart from the effects due to the stocking reduction, the whole post-intervention period was characterised with the influence of progressively increasing average air temperatures and similarly increasing ozone concentrations. Globally, the ozone concentrations on all plots were lower (average value 39 μg m-3 during the period 1999-2003 than in the following years 2004-2008 (average value 55 μg m-3. Maximum values measured in the growing season ranged from 36 to 140 μg m-3. The allowable limit exceeded 10 times in years 1999-2003 but 17 times in years 2004-2008, implying worsening conditions in Central European beech forest stands.

  5. Epiphytic lichen growth abnormalities and element concentrations as early indicators of forest decline

    Energy Technology Data Exchange (ETDEWEB)

    Otnyukova, T. [V.N. Sukachev' s Institute for Forest Research, Siberian Branch of Russian Academy of Sciences, Akademgorodok, Krasnoyarsk 660036 (Russian Federation)]. E-mail: t_otn@ksc.krasn.ru

    2007-03-15

    Thallus morphology and element concentrations (S, Al, Fe, Sr, Mn, Ni, Zn, Cu, Pb, As, F, and Cl) were compared in samples of the fruticose lichen genus Usnea at two heights of the Abies sibirica canopy in the East Sayan Mountains (Krasnoyarsk District, Russia) sampled from three stations at 15, 25 and 35 km from Krasnoyark. Usnea species with an abnormal morphology dominated on branches in the upper canopy, 15-22 m above ground level, and normal thalli on lower tree branches, 2-5 m above ground. Abnormal thalli at the tree-top level contained higher Al, Fe, Zn, F, Sr and Pb concentrations compared with normal thalli growing below, confirming a dust impact. No such clear trend was observed between sampling stations. Crown canopy architecture, surface microtopography and the balance between the processes of deposition and the movement and loss of particles play a major role in particle interception and in pollutant delivery to Usnea. - Differences in the morphology and element content of Usnea species at two distinct heights of the Abies sibirica canopy provide an early indication of forest decline.

  6. Algorithmic decision rules for estimating growth, removals, and mortality within a national-scale forest inventory (USA)

    Science.gov (United States)

    William H. McWilliams; Carol L. Alerich; William A. Bechtold; Mark Hansen; Christopher M. Oswalt; Mike Thompson; Jeff Turner

    2012-01-01

    The U.S. Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) program maintains the National Information Management System (NIMS) that provides the computational framework for the annual forest inventory of the United States. Questions regarding the impact of key elements of programming logic, processing criteria, and estimation procedures...

  7. Avian Assemblages Differ between Old-Growth and Mature White Pine Forests of Ontario, Canada: A Role for Supercanopy Trees?

    Directory of Open Access Journals (Sweden)

    David Anthony. Kirk

    2012-06-01

    Full Text Available We predicted that bird diversity and abundance of some bird species would be higher in old-growth stands than in mature pine stands because of the greater structural diversity in old growth. We also predicted that patch size of stands should be influential. To test these predictions, we modeled counts of 79 bird species from 52 stands in 5 regions in the province of Ontario, Canada in relation to habitat at the local and landscape extents. Neither total species richness nor abundance differed between stand types. No significant difference was found in bird assemblages between stand types using ordination analysis. However, more Neotropical migrants were found in old-growth stands than in mature stands, while the reverse was true for short-distance migrants. Twenty-five species had higher counts in old-growth stands - three significantly so: Brown Creeper Certhia americana, Northern Parula Setophaga americana, and Scarlet Tanager Piranga olivacea. Supercanopy pine (> 60 cm dbh was a significant (P 40 cm/dbh was a significant positive predictor for Brown Creeper, Pine Warbler Setophaga pinus, and total species richness. The density of supercanopy and medium/large pine explained a small but significant amount of variation in bird assemblages (1%, after considering age, other tree variables (9%, and landscape metrics. Patch size was significant for Evening Grosbeak Coccothraustes vespertinus and total abundance. According to receiver operating characteristic (ROC thresholds, Brown Creeper required a minimum of 62 stems/ha of medium/large pine. Pileated Woodpecker Dryocopus pileatus and Black-throated Green Warbler required a minimum of 14 and 23 stems/ha of supercanopy pine, respectively. Blackburnian Warbler Setophaga fusca required a minimum stand age of 66 years. Current targets in shelterwood seed cuts for pine appear to be just within range for Brown Creeper - at least for the first cut, but not for subsequent cuts. We recommend that forest

  8. Monitoring small pioneer trees in the forest-tundra ecotone: using multi-temporal airborne laser scanning data to model height growth.

    Science.gov (United States)

    Hauglin, Marius; Bollandsås, Ole Martin; Gobakken, Terje; Næsset, Erik

    2017-12-08

    Monitoring of forest resources through national forest inventory programmes is carried out in many countries. The expected climate changes will affect trees and forests and might cause an expansion of trees into presently treeless areas, such as above the current alpine tree line. It is therefore a need to develop methods that enable the inclusion of also these areas into monitoring programmes. Airborne laser scanning (ALS) is an established tool in operational forest inventories, and could be a viable option for monitoring tasks. In the present study, we used multi-temporal ALS data with point density of 8-15 points per m 2 , together with field measurements from single trees in the forest-tundra ecotone along a 1500-km-long transect in Norway. The material comprised 262 small trees with an average height of 1.78 m. The field-measured height growth was derived from height measurements at two points in time. The elapsed time between the two measurements was 4 years. Regression models were then used to model the relationship between ALS-derived variables and tree heights as well as the height growth. Strong relationships between ALS-derived variables and tree heights were found, with R 2 values of 0.93 and 0.97 for the two points in time. The relationship between the ALS data and the field-derived height growth was weaker, with R 2 values of 0.36-0.42. A cross-validation gave corresponding results, with root mean square errors of 19 and 11% for the ALS height models and 60% for the model relating ALS data to single-tree height growth.

  9. Earthworms as indicators for different forest management types and human disturbance in Ilam oak forest, Iran

    Directory of Open Access Journals (Sweden)

    Heydari Mehdi

    2014-09-01

    Full Text Available There has been observed widespread destruction of natural ecosystems around the world due to population growth, land use change and clear cutting which have affected soil properties. Different management strategies have been so far implemented to reduce this crisis in various regions of the world, such as e.g. short-term and long-term conservation management in the Zagros region. However, any management approach should be evaluated with appropriate measures to determine how managed areas respond. The main objective of the present study was to evaluate the potential of earthworms as an indicator for different forest management strategies and human disturbances in Zagros oak (Quercus persica Jaub. and Spach forest. The sites selected included undisturbed one as the control (Un, the sites under five-year conservation management (FCM and twenty-year conservation management (TCM as well as the disturbed site (D. The results of principal component analysis (PCA showed that different regions separated into the components: PC1 and PC2. Un and TCM sites gathered together and represented higher values of the factors such as pH, Kavailable, OC, clay content, Pavailable, CEC, overstory tree canopy, Ntot, biomass and abundance of earthworms. The positive direction of the first axis reflected a gradient of EC, BD and Ptot. According to the logistic model, NH4-N and EC played the most important role in earthworm presence and absence in Zagros forest ecosystem. Earthworm abundance and biomass could be a good indicator to evaluate different forest management strategies in the study area.

  10. Assessing forest vulnerability to climate warming using a process-based model of tree growth: bad prospects for rear-edges.

    Science.gov (United States)

    Sánchez-Salguero, Raúl; Camarero, Jesus Julio; Gutiérrez, Emilia; González Rouco, Fidel; Gazol, Antonio; Sangüesa-Barreda, Gabriel; Andreu-Hayles, Laia; Linares, Juan Carlos; Seftigen, Kristina

    2017-07-01

    Growth models can be used to assess forest vulnerability to climate warming. If global warming amplifies water deficit in drought-prone areas, tree populations located at the driest and southernmost distribution limits (rear-edges) should be particularly threatened. Here, we address these statements by analyzing and projecting growth responses to climate of three major tree species (silver fir, Abies alba; Scots pine, Pinus sylvestris; and mountain pine, Pinus uncinata) in mountainous areas of NE Spain. This region is subjected to Mediterranean continental conditions, it encompasses wide climatic, topographic and environmental gradients, and, more importantly, it includes rear-edges of the continuous distributions of these tree species. We used tree-ring width data from a network of 110 forests in combination with the process-based Vaganov-Shashkin-Lite growth model and climate-growth analyses to forecast changes in tree growth during the 21st century. Climatic projections were based on four ensembles CO 2 emission scenarios. Warm and dry conditions during the growing season constrain silver fir and Scots pine growth, particularly at the species rear-edge. By contrast, growth of high-elevation mountain pine forests is enhanced by climate warming. The emission scenario (RCP 8.5) corresponding to the most pronounced warming (+1.4 to 4.8 °C) forecasted mean growth reductions of -10.7% and -16.4% in silver fir and Scots pine, respectively, after 2050. This indicates that rising temperatures could amplify drought stress and thus constrain the growth of silver fir and Scots pine rear-edge populations growing at xeric sites. Contrastingly, mountain pine growth is expected to increase by +12.5% due to a longer and warmer growing season. The projections of growth reduction in silver fir and Scots pine portend dieback and a contraction of their species distribution areas through potential local extinctions of the most vulnerable driest rear-edge stands. Our modeling

  11. Associations between growth, wood anatomy, carbon isotope discrimination and mortality in a Quercus robur forest.

    Science.gov (United States)

    Levanic, Tom; Cater, Matjaz; McDowell, Nate G

    2011-03-01

    Observations of forest mortality are increasing globally, but relatively little is known regarding the underlying mechanisms driving these events. Tree rings carry physiological signatures that may be used as a tool for retrospective analyses. We capitalized on a local soil water drainage event in 1982 that resulted in increased mortality within a stand of oak trees (Quercus robur), to examine the underlying physiological patterns associated with survival and death in response to soil water limitations. Pre-dawn water potentials showed more negative values for trees in the process of dying compared with those that survived. We used tree rings formed over the 123 years prior to mortality to estimate productivity from basal area increment (BAI, mm(2)), multiple xylem hydraulic parameters via anatomical measurements and crown-level gas exchange via carbon isotope discrimination (Δ, ‰). Oaks that died had significantly higher BAI values than trees that survived until the drainage event, after which the BAI of trees that died declined dramatically. Hydraulic diameter and conductivity of vessels in trees that died were higher than in surviving trees until the last 5 years prior to mortality, at which time both groups had similar values. Trees that died had consistently lower Δ values than trees that survived. Therefore, tree mortality in this stand was associated with physiological differences prior to the onset of soil water reduction. We propose that trees that died may have been hydraulically underbuilt for dry conditions, which predisposes them to severe hydraulic constraints and subsequent mortality. Measurements of above-ground/below-ground dry mass partitioning will be critical to future tests of this hypothesis. Based on these results, it is probable that pedunculate oak trees will experience greater future mortality if climate changes cause more severe droughts than the trees have experienced previously.

  12. Sediment movement from forest road systems-roads: a major contributor to erosion and stream sedimentation

    Science.gov (United States)

    Johnny M. Grace

    2002-01-01

    Nonpoint source pollution is a major concern related to natural resource management throughout the United States. Undisturbed forest lands typically have minimal erosion, less than 0.13 ton/acre (0.30 ton/hectare), due to the increased cover and surface roughness found in these areas. However, disturbances caused by forest management practices can result in...

  13. Sediment Production in Forests of the Coastal Plain, Piedmont, and Interior Highlands

    Science.gov (United States)

    Daniel A. Marion; S.J. Ursic

    1993-01-01

    A primary environmental concern related to forestry in the South is the effects of forests and forestry practices on sediment production. Sediment is the most significant pollutant of southern waters. A liability in itself, sediment also accounts for most nutrients removed by water. This paper discusses sediment production from small catchments of undisturbed forests...

  14. Growth-Climate Response of Young Turkey Oak (Quercus cerris L. Coppice Forest Stands along Longitudinal Gradient in Albania

    Directory of Open Access Journals (Sweden)

    Merita Stafasani

    2015-06-01

    Full Text Available Background and Purpose: Turkey oak (Quercus cerris L. is the most widespread species in Albania and less investigated from dendroclimatological point of view. Previous studies have reported that Q. cerris is sensitive to the environment when growing at different latitudes and ecological conditions. Based on this fact we have explored the response of different Q. cerris populations located along the longitudinal gradient. Materials and Methods: The stem discs were sampled from six sites (Kukes, Diber, Rreshen, Ulez, Elbasan, Belsh along longitudinal gradient ranging from north-east to central Albania. All oak forests stands grow under the influence of specific local Mediterranean climate. Tree-ring widths were measured to the nearest 0.001 mm using a linear table, LINTAB and the TSAP-Win program. Following the standard dendrochronological procedures residual tree-ring width chronologies were built for each site. Statistical parameters commonly used in dendrochronology were calculated for each site chronology. Relations between the tree-ring chronologies were explored using Hierarchical Factor Classification (HFC and Principal Component Analysis (PCA, while the radial growth-climate relationship was analyzed through correlation analysis using a 19-month window from April in the year prior to tree-ring formation (year t - 1 until October in the year of growth (year t. Results and Conclusions: The length of the site chronologies ranged from 16 to 36 years, with the Elbasan site chronology being the longest and the Belsh site chronology the shortest one. Trees at lower elevation were younger than trees at higher elevation. Statistical parameters (mean sensitivity (MS and auto correlation (AC of site chronologies were different among them and lower values of AC1 showed a weaker dependence of radial growth from climatic conditions of the previous growing year. Principal component analysis showed that Belsh, Rreshen and Elbasan site chronologies were

  15. Nitrogen transformations and greenhouse gas emissions from a riparian wetland soil: An undisturbed soil column study

    Energy Technology Data Exchange (ETDEWEB)

    Munoz-Leoz, Borja [Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, E-48013 Bilbao (Spain); Antigueedad, Inaki [Department of Geodynamic, University of the Basque Country, UPV/EHU, E-48940 Leioa (Spain); Garbisu, Carlos [Department of Ecosystems, NEIKER-Tecnalia, E-48160 Derio (Spain); Ruiz-Romera, Estilita, E-mail: estilita.ruiz@ehu.es [Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, E-48013 Bilbao (Spain)

    2011-01-15

    Riparian wetlands bordering intensively managed agricultural fields can act as biological filters that retain and transform agrochemicals such as nitrate and pesticides. Nitrate removal in wetlands has usually been attributed to denitrification processes which in turn imply the production of greenhouse gases (CO{sub 2} and N{sub 2}O). Denitrification processes were studied in the Salburua wetland (northern Spain) by using undisturbed soil columns which were subsequently divided into three sections corresponding to A-, Bg- and B2g-soil horizons. Soil horizons were subjected to leaching with a 200 mg NO{sub 3}{sup -} L{sup -1} solution (rate: 90 mL day{sup -1}) for 125 days at two different temperatures (10 and 20 {sup o}C), using a new experimental design for leaching assays which enabled not only to evaluate leachate composition but also to measure gas emissions during the leaching process. Column leachate samples were analyzed for NO{sub 3}{sup -} concentration, NH{sub 4}{sup +} concentration, and dissolved organic carbon. Emissions of greenhouse gases (CO{sub 2} and N{sub 2}O) were determined in the undisturbed soil columns. The A horizon at 20 {sup o}C showed the highest rates of NO{sub 3}{sup -} removal (1.56 mg N-NO{sub 3}{sup -} kg{sup -1} DW soil day{sup -1}) and CO{sub 2} and N{sub 2}O production (5.89 mg CO{sub 2} kg{sup -1} DW soil day{sup -1} and 55.71 {mu}g N-N{sub 2}O kg{sup -1} DW soil day{sup -1}). For the Salburua wetland riparian soil, we estimated a potential nitrate removal capacity of 1012 kg N-NO{sub 3}{sup -} ha{sup -1} year{sup -1}, and potential greenhouse gas emissions of 5620 kg CO{sub 2} ha{sup -1} year{sup -1} and 240 kg N-N{sub 2}O ha{sup -1} year{sup -1}. - Research Highlights: {yields}A new experimental design is proposed for leaching assays to simulate nitrogen transformations in riparian wetland soil. {yields}Denitrification is the main process responsible for nitrate removal in the riparian zone of Salburua wetland. {yields

  16. Colloid mobilization in an undisturbed sediment core under semiarid recharge rates

    Science.gov (United States)

    Liu, Ziru; Flury, Markus; Harsh, James B.; Mathison, Jon B.; Vogs, Carolina

    2013-08-01

    The semiarid US Department of Energy Hanford site has a deep vadose zone with low recharge rates. Contaminants originating from nuclear waste processing are expected to move slowly through the vadose zone. The movement of certain contaminants can be facilitated by colloids. We hypothesized that the low recharge rates and low water contents in semiarid regions, however, tend to inhibit movement of colloidal particles, thereby reducing the risk for colloid-facilitated contaminant transport. The goal of this study was to investigate whether in situ natural colloids can be mobilized and transported in undisturbed, deep vadose zone sediments at the Hanford site under typical, semiarid recharge rates. We sampled an undisturbed sediment core (i.d. 50 cm, 59.5 cm height) from a depth of 17 m below ground at the Hanford 200 Area. The core was set up as a laboratory lysimeter and exposed to an infiltration rate of 18 mm/yr by applying simulated pore water onto the surface. Particle concentrations were quantified in the column outflow, and selected samples were examined microscopically and for elemental composition (transmission electron microscopy and energy dispersive X-ray). Measured water contents and potentials were used to calibrate a numerical model (HYDRUS-1D), which was then applied to simulate colloid mobilization from the sediment core. During 5.3 years of monitoring, natural colloids like silicates, aluminosilicates, and Fe-oxides were observed in the core outflow, indicating the continuous mobilization of in situ colloids. The total amount of particles mobilized during 5.3 years corresponded to 1.1% of the total dispersible colloids inside the core. Comparison of the amounts of colloids released with weathering rates suggests that mineral weathering can be a major source of the mobilized colloids. The fitted colloid release rate coefficient was 6 to 7 orders of magnitude smaller than coefficients reported from previous studies, where disturbed Hanford sediments

  17. Montane forest root growth and soil organic layer depth as potential factors stabilizing Cenozoic global change

    Science.gov (United States)

    Doughty, Christopher E.; Taylor, Lyla L.; Girardin, Cecile A. J.; Malhi, Yadvinder; Beerling, David J.

    2014-02-01

    Tree roots and their symbiotic fungal partners are believed to play a major role in regulating long-term global climate, but feedbacks between global temperature and biotic weathering have not yet been explored in detail. In situ field data from a 3000 m altitudinal transect in Peru show fine root growth decreases and organic layer depth increases with the cooler temperatures that prevail at increased altitude. We hypothesize that this observation suggests a negative feedback: as global temperatures rise, the soil organic layer will shrink, and more roots will grow in the mineral layer, thereby accelerating weathering and reducing atmospheric CO2. We examine this mechanism with a process-based biological weathering model and demonstrate that this negative feedback could have contributed to moderating long-term global Cenozoic climate during major Cenozoic CO2 changes linked to volcanic degassing and tectonic uplift events.

  18. Local environment and density-dependent feedbacks determine population growth in a forest herb

    DEFF Research Database (Denmark)

    Dahlgren, Johan Petter; Östergård, Hannah; Ehrlén, Johan

    2014-01-01

    Linking spatial variation in environmental factors to variation in demographic rates is essential for a mechanistic understanding of the dynamics of populations. However, we still know relatively little about such links, partly because feedbacks via intraspecific density make them difficult...... shade on survival and growth, while density was negatively correlated with these vital rates. Density was also negatively correlated with average individual size in the study plots, which is consistent with self-thinning. In addition, average plant sizes were larger than predicted by density in plots...... similar to those observed in the field. The results illustrate how the local environment can determine dynamics of populations and that intraspecific density may have to be more carefully considered in studies of plant demography and population viability analyses of threatened species. We conclude...

  19. The Net Carbon Flux due to Deforestation and Forest Re-Growth in the Brazilian Amazon: Analysis using a Process-Based Model

    Science.gov (United States)

    Hirsch, A. I.; Little, W. S.; Houghton, R. A.; Scott, N. A.; White, J. D.

    2004-01-01

    We developed a process-based model of forest growth, carbon cycling, and land cover dynamics named CARLUC (for CARbon and Land Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study of the impact of Amazonian deforestation, selective logging, and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970-1998. We calculate that the net flux to the atmosphere during this period reached a maximum of approx. 0.35 PgC/yr (1PgC = 1 x 10(exp I5) gC) in 1990, with a cumulative release of approx. 7 PgC from 1970- 1998. The net flux is higher than predicted by an earlier study by a total of 1 PgC over the period 1989-1 998 mainly because CARLUC predicts relatively high mature forest carbon storage compared to the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by approx. 1 PgC from 1970-1998, while different assumptions about land cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).

  20. Solarization of nursery soil induces production of fruit bodies of mushrooms and enhances growth of tropical forest tree seedlings

    Directory of Open Access Journals (Sweden)

    R.K. Verma

    2010-12-01

    Full Text Available The aim of this work was to find out the effect of soil solarization on microbial population and its effect on growth of two species of tropical forest trees. For this purpose, solar heating of nursery seedbeds (1 x 5m was done during April- May 2009 for one month, by application of a thin clear sheet of polyethylene. The top soil (5 inches consists of a mix of loam soil, sand and farm yard manure in 2:1:0.5 ratios (v/v. Temperature variations were recorded daily for a period of one month, at 2 depths, (5 cm and 10 cm. Maximum differences in temperature between solar treatment and control was recorded as high as 12.1° C at 5 cm and 9.1° C at 10 cm depth. After one month, population of Aspergillus, Fusarium, Penicillium, Rhizopus and nematodes were completely eliminated from upper 5 cm depth, although population of AM fungi, bacteria and Trichoderma were reduced, but not completely eliminated. Seedlings of Gmelina arborea Roxb. and Tectona grandis Linn.f. were raised through seeds on treated and control beds. After three months, the production of fruit bodies of mushrooms, namely Amanita populiphila Tullos & E. Moses, Lepiota longicauda Henn. and Scleroderma sp. were observed. It was noticed that these mushrooms only appeared on treated soil with white mycelial growth in rhizosphere under fruit bodies. Lepiota longicauda produced the maximum number of fruit bodies on teak seedbeds followed by Scleroderma sp. on G. arborea seedbeds. Due to solar heating there was 23.9% increase in plant height and 22.1% increase in collar diameter of G. arborea seedlings, where as 17.4% increase in plant height and 9.8% increase in collar diameter in case of T. grandis, as compared to control seedlings.

  1. EFFECT OF ARBUSCULAR MYCORRHIZAL COLONIZATION ON EARLY GROWTH AND NUTRIENT CONTENT OF TWO PEAT­ SWAMP FOREST TREE SPECIES SEEDLINGS, Calophyllum hosei AND Ploiarium alternifolium

    Directory of Open Access Journals (Sweden)

    Maman Turjaman

    2006-03-01

    Full Text Available Tropical peat-swamp forests are one of  the largest near-surface reserves of terrestrial organic carbon,  but rnany peat-swamp forest tree species decreased due over-exploitation, forest fire and conversion of natural forests into agricultural lands. Among those species are slow-growing Calophyllum  hoseiand Ploiarium  alternifolium, two species are good for construction of boats, furniture, house building and considerable attention from pharmacological viewpoint for human healthly. This study was aimed at understanding the effects of arbuscular mycorrhizal (AM fungi on early growth of  C. hosei and P.alternifoliumunder greenhouse condition. Seedlings of C. hosei and P.alternifoliumwere inoculated with AM fungi: Glomus clarum and Glomus aggregatum ,or uninoculated under greenhouse condition during 6 months. AM colonization,   plant growth,  survival rate and  nutrient  content  (P, Zn  and B were measured. The percentage of C. hoseiand P.alternifolium ranged from 27-32% and 18-19%,  respectively. Both inoculated seedling species had greater plant  height, diameter, leaf number, shoot and root dry weight than control  seedlings.   Nutrient  content  of  inoculated  plants  were increased with AM colonization- Survival rates of  inoculated plants were higher (100%  than those of  control plants (67%. The results suggested that inoculation of AM fungi could improve the early growth of C. hoseiand P.alternifolium grown in tropical peat-swamp forest therefore  this finding has greater potential impact if this innovative technology applied in field scales which are socially acceptable, commercially profitable and environmentally friendly.

  2. Biophysical controls of carbon exchange in old growth Mountain Ash stands

    Science.gov (United States)

    Kilinc, M.; Beringer, J.; Hutley, L.; Tapper, N.; McGuire, D.; Kurioka, K.; Wood, S.; D'Argent, N.

    2008-12-01

    Long-term measurements of CO2, H2O and energy fluxes over a range of terrestrial ecosystem types and maturity are necessary in determining the regional and global carbon budgets. Previous studies from temperate forests have generally shown that the net uptake of carbon (NEE) of ecosystems decreases with stand age, and in old growth forests carbon cycling has often been assumed to be in equilibrium. However, results from the Northern Hemisphere, using eddy covariance flux towers, indicate that old growth forests are a greater sink than first thought. Changes in stand structure, detritus matter and microclimate between young and old growth forests greatly contribute to the variation in the net fluxes of CO2 and H2O. The role of old growth temperate forests in Australia is uncertain and may function remarkably different to their deciduous counterparts in the Northern Hemisphere. An undisturbed old growth, Mountain Ash (Eucalyptus regnans) ecosystem, located in the Central Highlands of Victoria (Australia) has been selected as a permanent study site to investigate carbon and water budgets over diurnal, seasonal and annual cycles. Mountain Ash trees are the world's tallest angiosperms (flowering plant), and fully developed trees can reach heights of more than 100 metres. Mountain Ash forests also occupy a large proportion of Victoria's catchments, making them a crucial resource for the sustainable management and quality of Melbourne's drinking water. This study uses the Eddy Covariance method, which will measure the carbon, water, energy fluxes. The site has been running since August 2005 and we present 18 months of preliminary results from the site. The central theme of this study is to investigate the climatic and biophysical factors that control carbon, water and energy cycles over a range of time scales. Ultimately, this approach will allow us to better understand how these uniquely Australian ecosystems may respond to global climate change.

  3. Factors that influence the oxidation of the manganese in a growth of mangroves forest, Itacuruca, R J

    International Nuclear Information System (INIS)

    Canesin, F.P.; Bellido, A.V.B.; Lacerda, L.D.

    1999-01-01

    The kinetic behavior of the oxidation of the manganese in the growth of mangroves forest, Itacuruca, Sepetiba Bay, R J, have been studied through the incubation with the radiotracer Mn-54. We have observed the great influence of the factors that interferes in the rate oxidation with the mangrove state in the moment of the sampling. We applied statistical multivariate to verify the correlation with the tide height and the physical-chemical parameters. With the program Statistical Analysis System, SAS, the samples were classified by hierarchical conglomerate methods and Factor Analysis. Water samples were collected in the entrance of the tide channel in five campaigns in the months of August, September, November and December of 98, and January of 99, in several tide heights. As a conclusion, by the multivariate statistical analysis where variables correlations are presented in each group or cluster in a population. Therefore the variables that we are measuring as reflecting the influence the oxidation manganese in the mangroves. Although the variable tide height did not influence in the classification groups. We suppose that will need more sampling in different tide height cycle. (author)

  4. Comparative study of methods to estimate hydraulic parameters in the hydraulically undisturbed Opalinus Clay (Switzerland)

    Energy Technology Data Exchange (ETDEWEB)

    Yu, C.; Matray, J.-M. [Institut de Radioprotection et de Sûreté Nucléaire, Fontenay-aux-Roses, (France); Yu, C.; Gonçalvès, J. [Aix Marseille Université UMR 6635 CEREGE Technopôle Environnement Arbois-Méditerranée Aix-en-Provence, Cedex 4 (France); and others

    2017-04-15

    The deep borehole (DB) experiment gave the opportunity to acquire hydraulic parameters in a hydraulically undisturbed zone of the Opalinus Clay at the Mont Terri rock laboratory (Switzerland). Three methods were used to estimate hydraulic conductivity and specific storage values of the Opalinus Clay formation and its bounding formations through the 248 m deep borehole BDB-1: application of a Poiseuille-type law involving petrophysical measurements, spectral analysis of pressure time series and in situ hydraulic tests. The hydraulic conductivity range in the Opalinus Clay given by the first method is 2 × 10{sup -14}-6 × 10{sup -13} m s{sup -1} for a cementation factor ranging between 2 and 3. These results show low vertical variability whereas in situ hydraulic tests suggest higher values up to 7 × 10{sup -12} m s{sup -1}. Core analysis provides economical estimates of the homogeneous matrix hydraulic properties but do not account for heterogeneities at larger scale such as potential tectonic conductive features. Specific storage values obtained by spectral analysis are consistent and in the order of 10{sup -6} m{sup -1}, while formulations using phase shift and gain between pore pressure signals were found to be inappropriate to evaluate hydraulic conductivity in the Opalinus Clay. The values obtained are globally in good agreement with the ones obtained previously at the rock laboratory. (authors)

  5. The ecological half-life of 137Cs in undisturbed silt soil

    International Nuclear Information System (INIS)

    Drosg, M.

    2012-01-01

    The time necessary to safely cultivate agricultural areas after they have been contaminated by radioactivity (e.g. after the Chernobyl accident) is not determined by the physical half-life of the radioactive isotopes in question but by their (usually much shorter) ecological half-life (). This half-life not only depends on the type of soil but also on whether the soil was fertilized or not. Therefore it is not possible to determine an ecological half-life that is universally valid. However, the value for undisturbed, unfertilized soil should provide a general indication for the duration of ecological half-life. In a silt soil in Vienna, Austria, the ecological half-life of 137 Cs was determined to be 0.8 years, which is much shorter than the physical half-life of 30 years. - Highlights: ► Absolute measurements of 137 Cs radioactivity in leaves of perennial plants. ► The natural 40 K radioactivity served as reference. ► The ecological half-life of 137 Cs in loamy soil was determined.

  6. Resistance of undisturbed soil microbiomes to ceftriaxone indicates extended spectrum β-lactamase activity

    Directory of Open Access Journals (Sweden)

    Joao eGatica

    2015-11-01

    Full Text Available Emergence and spread of antibiotic resistance, and specifically resistance to third generation cephalosporins associated with extended spectrum β-lactamase (ESBL activity, is one of the greatest epidemiological challenges of our time. In this study we addressed the impact of the third generation cephalosporin ceftriaxone on microbial activity and bacterial community composition of two physically and chemically distinct undisturbed soils in highly regulated microcosm experiments. Surprisingly, periodical irrigation of the soils with clinical doses of ceftriaxone did not affect their microbial activity; and only moderately impacted the microbial diversity (α and β of the two soils. Corresponding slurry experiments demonstrated that the antibiotic capacity of ceftriaxone rapidly diminished in the presence of soil, and approximately 70% of this inactivation could be explained by biological activity. The biological nature of ceftriaxone degradation in soil was supported by microcosm experiments that amended model Escherichia coli strains to sterile and non-sterile soils in the presence and absence of ceftriaxone and by the ubiquitous presence of ESBL genes (blaTEM, blaCTX-M and blaOXA in soil DNA extracts. Collectively, these results suggest that the resistance of soil microbiomes to ceftriaxone stems from biological activity and even more, from broad-spectrum β-lactamase activity; raising questions regarding the scope and clinical implications of ESBLs in soil microbiomes.

  7. Pore Space Statistics From the X-ray CT of Large Undisturbed Soil Columns

    Science.gov (United States)

    Martin, M. A.; Tuller, M.; Guber, A. K.; García-Gutiérrez, C.; San Jose Martinez, F.; Pachepsky, Y. A.; Caniego, J. F.

    2007-12-01

    Large soil columns need to be studied to infer geometric properties of macropores and their role in flow and transport phenomena, especially when colloid or colloid-facilitated transport is of interest. We have sampled and studied undisturbed columns (7.5 cm ID, 20 cm length) of the Taylor soil from a grassed floodplain. A FlashCTTM - 420 kV system (HYTEC Inc.) was used for X-ray computer tomography (CT) scanning. The FlashCT-DAQ, the FlashCT-DPS, and the FlashCT-VIZ software was used for reconstruction. A MatLab® software with GUI for processing, analyzing and visualizing of 3D X-ray CT scans was developed. It was used in the binarization process on each of 1480 cross-section images obtained for each column. The resolution of about 100 mkm was sufficient to distinguish macropores. The high-connectivity macropore space was reconstructed from the imagery, as well. The "porosity-depth" data series have been investigated. The R/S (rescale range) analysis indicated that these series did not have a simple structure that might be understood as a persistent or antipersistent fractional Brownian motion using the Hurst exponent. More complex behavior had been detected that could be characterized by means of multifractal analysis. The water retention data were obtained for column sections and were related to the CT characterization of these sections. Large columns present feasible objects for CT if macroporosity is of interest.

  8. Vertical migration of 85Sr, 137Cs and 131I in various arable and undisturbed soils

    International Nuclear Information System (INIS)

    Palagyi, S.; Palagyiova, J.

    2002-01-01

    Vertical migration of 85 Sr, 137 Cs and 131 I in some arable and undisturbed single-contaminated soils was studied by gamma-spectrometry measurements in lysimetric laboratory conditions applying irrigation of the soil profiles with wet atmospheric precipitation for about one year (except radioiodine). A new simple exponential compartment (box) model was derived, allowing us to calculate the migration rate constants and migration rates in the individual soil layers (vertical sections) as well as the total vertical migration rate constants and total vertical migration rates of radionuclides in the bulk soil horizon. The data from the time dependence of the depth activity distribution (radionuclide concentration along the vertical soil profile) were used to test the model. The migration rate constants and migration rates were found to be affected by the contaminating radionuclides as well as by the site, type and depth of the soil. The relaxation times of the radionuclides in the soil horizons were calculated. The effects on the rate parameters of the permanent grass cover and the zeolite applied onto the arable soil surfaces were also investigated

  9. 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.

  10. Local environment and density-dependent feedbacks determine population growth in a forest herb.

    Science.gov (United States)

    Dahlgren, Johan P; Ostergård, Hannah; Ehrlén, Johan

    2014-12-01

    Linking spatial variation in environmental factors to variation in demographic rates is essential for a mechanistic understanding of the dynamics of populations. However, we still know relatively little about such links, partly because feedbacks via intraspecific density make them difficult to observe in natural populations. We conducted a detailed field study and investigated simultaneous effects of environmental factors and the intraspecific density of individuals on the demography of the herb Lathyrus vernus. In regression models of vital rates we identified effects associated with spring shade on survival and growth, while density was negatively correlated with these vital rates. Density was also negatively correlated with average individual size in the study plots, which is consistent with self-thinning. In addition, average plant sizes were larger than predicted by density in plots that were less shaded by the tree canopy, indicating an environmentally determined carrying capacity. A size-structured integral projection model based on the vital rate regressions revealed that the identified effects of shade and density were strong enough to produce differences in stable population sizes similar to those observed in the field. The results illustrate how the local environment can determine dynamics of populations and that intraspecific density may have to be more carefully considered in studies of plant demography and population viability analyses of threatened species. We conclude that demographic approaches incorporating information about both density and key environmental factors are powerful tools for understanding the processes that interact to determine population dynamics and abundances.

  11. Ant species richness of fynbos and forest ecosystems in the ...

    African Journals Online (AJOL)

    The ant fauna in fynbos and forest habitats in the southern Cape are compared. There is no significant difference in ant species richness between the two undisturbed habitat types, and the only two species common to both are Acantholepis capensis and Camponotus maculatus. The degree of Hakea sericea infestation in ...

  12. Water budgets of two forested watersheds in South Carolina

    Science.gov (United States)

    Ge Sun; Jianbiao Lu; David L. Gartner; Masato Miwa; Carl C. Trettin

    2000-01-01

    Wetland protection, restoration and management require detail information of the water budgets for a particular system. Relatively undisturbed systems with long-term hydrologic records are extremely valuable for developing reference wetlands and detecting effects of management. Two forested flatwoods watersheds in the lower coastal plain of South Carolina have been...

  13. Characteristics and classification of soils of Gora Daget forest, South ...

    African Journals Online (AJOL)

    As a result there are few sites where undisturbed soils exist for use as a reference against which the impacts of land use can be evaluated. The Gora Daget forest on a very steep slope located close to Dessie town provides one of these rare opportunities for the type of investigation. Three pairs of representative soil profiles ...

  14. 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.

  15. Stem anatomical characteristics of the climbing palm Desmoncus orthacanthos (Arecaceae under two natural growth conditions in a tropical forest

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    Joaquín Quiroz

    2008-06-01

    Full Text Available Desmoncus orthacanthos is a Neotropical climbing palm that resembles rattan and therefore has similar potential applications. The genus Desmoncus (subfamily Arecoideae, subtribe Bactridinae is distributed throughout the Americas, from veracruz, Mexico, to Brazil and Bolivia. The anatomical characteristics of its support tissue have not been thoroughly studied, although some observations from Central American artisans suggest that the stems collected from undisturbed sites possess better characteristics; these include a good capacity to withstand bending without breaking (i.e. higher fracture strength than plants from disturbed sites. Stem samples were collected from individuals from disturbed and undisturbed sites, at three points along the length of the stem (basal, medium and apical. Collections were made of one ramet from five individuals (n=5 at both sites. Each ramet was divided into three sections: basal, from soil surface to a height of 0.5 m; medium, from a height of 0.5 to 5.0 m; and apical, from a height 5.0 to 10.0 m. An anatomical analysis including vascular bundles, parenchyma elements and fibers was performed in the radial direction and also along the longitudinal direction of the stems. The amount of vascular bundles was greater for samples from undisturbed site stems; the amount of parenchyma cells differ between samples from both sites and the amount of fibers was greater for samples from disturbed site stems. The anatomical structural dimensions were smaller for samples from the undisturbed site stems. These findings partially confirm the artisans’ belief and supports the conclusion that microclimatic conditions affect plant anatomical structure. Rev. Biol. Trop. 56 (2: 937-949. Epub 2008 June 30.Desmoncus orthacanthos es una palmera trepadora neotropical que puede, potencialmente, utilizarse en usos similares a los del ratán. El género Desmoncus (subfamilia Arecoideae, subtribu Bactridinae se distribuye en América desde

  16. Outbreak of Drepanopeziza fungus in aspen forests and variation in stand susceptibility: leaf functional traits, compensatory growth and phenology.

    Science.gov (United States)

    Call, Anson C; St Clair, Samuel B

    2017-09-01

    In the spring of 2015, a severe outbreak of the necrotrophic pathogen Drepanopeziza (also known as Marssonina) spread across large portions of aspen (Populus tremuloides Michx.) forests in the western United States. Among adjacent stands, some were diseased and others were not. Drepanopeziza infection in diseased aspen stands stimulated compensatory growth of second-flush leaves at the top of the canopy. These patterns of infection provided an opportunity to characterize associations of pathogen infection and leaf functional traits. Eight pairs of adjacent healthy and diseased aspen stands were identified across a forest landscape in northern Utah. Average leaf surface area, specific leaf area (SLA), photosynthesis, starch concentration and defense chemistry expression (phenolic glycosides and condensed tannins) were measured on original, first-flush leaves in the lower portion of the tree canopy of healthy and diseased stands and compensatory, second-flush leaves produced in the canopy top of diseased stands. Only first-flush leaves of diseased stands showed high levels of Drepanopeziza infection. Leaf area of second-flush leaves of diseased stands was threefold larger than all other leaf types in healthy or diseased stands. Lower canopy leaves of healthy stands had the highest SLA. Photosynthesis was lowest in infected first-flush leaves, highest in second-flush leaves of diseased stands and intermediate in leaves of healthy stands. Foliar starch concentrations were lower in leaves of diseased stands than leaves from healthy stands. Condensed tannins were greater in second-flush leaves than first-flush leaves in both healthy and diseased stands. Phenolic glycoside concentrations were lowest in infected leaves of diseased stands. Diseased stands leafed out a week earlier in the spring than healthy stands, which may have exposed their emerging leaves to rainy conditions that promote Drepanopeziza infection. Compensatory leaf regrowth of diseased stands appears to

  17. Association between Soil Fertility and Growth Performance of Planted Shorea macrophylla (de Vriese after Enrichment Planting at Rehabilitation Sites of Sampadi Forest Reserve, Sarawak, Malaysia

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    Mugunthan Perumal

    2017-01-01

    Full Text Available A study was conducted to determine the status of soil properties after enrichment planting in comparison to an adjacent secondary forest and to evaluate the effect of enrichment planting of Shorea macrophylla (de Vriese on the soil fertility status with special reference to Soil Fertility Index (SFI and Soil Evaluation Factor (SEF at Sampadi Forest Reserve, Sarawak. The study sites were stands rehabilitated in different years (1996: SM96; 1997: SM97; 1998: SM98; 1999: SM99 and secondary forest (SF. Findings indicated that the soils at rehabilitation sites and SF were strongly acidic in nature, with pH less than 5.50, poor soil exchangeable bases, and nutrient status. The soils were relatively of sandy clay loam to sandy clay. Principal Component Analysis revealed the three most significant components of the soil properties which explained 76.3% of the total variation. At surface soils, SFI was correlated with tree growth parameters of S. macrophylla, indicating that SFI is an applicable soil quality index as compared to SEF. Notwithstanding, a significant association was found between soil available phosphorus and planted S. macrophylla, indicating that soil phosphorus is a better indicator than SFI. Further studies on other environmental factors influencing tree growth performance, early establishment of experimental reforestation at nursery, and field should be implemented to obtain the initial data on seedling growth performance prior to outplanting.

  18. An old-growth forest at the Caspian Sea coast is similar in epiphytic lichens to lowland deciduous forests in Central Europe

    Czech Academy of Sciences Publication Activity Database

    Ismailov, A.; Urbanavichus, G.; Vondrák, Jan; Pouska, V.

    2017-01-01

    Roč. 30, č. 1 (2017), s. 103-125 ISSN 0018-0971 Institutional support: RVO:67985939 Keywords : Dagestan * forest protection * lowland fores indicator Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 0.740, year: 2016

  19. Discrimination between acute and chronic decline of Central European forests using map algebra of the growth condition and forest biomass fuzzy sets: A case study

    Czech Academy of Sciences Publication Activity Database

    Samec, P.; Caha, J.; Zapletal, M.; Tuček, P.; Cudlín, Pavel; Kučera, M.

    599-600, DEC (2017), s. 899-909 ISSN 0048-9697 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:67179843 Keywords : abiotic predictors * Forest decline * Fuzzy modelling * Nitrogen deposition * Soil carbon Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7) Impact factor: 4.900, year: 2016

  20. Importance of Small Isolated Wetlands for Herpetofaunal Diversity in Managed, Young Growth Forests in the Coastal Plain of South Carolina

    International Nuclear Information System (INIS)

    Russell, K.R.; Guynn, D.C. Jr.; Hanlin, H.G.

    2002-01-01

    Assessment and comparison of richness, abundance and difference of herpetofauna at five small isolated wetlands located within a commercial forest landscape in the South Carolina Coastal Plain. Data indicates small isolated wetlands are focal points of herpetofaunal richness and abundance in managed coastal plain forest and contribute more to regional biodiversity than is implied by their small size or ephemeral hydrology

  1. Forest Management Effects on Surface Soil Carbon and Nitrogen

    Science.gov (United States)

    Jennifer D. Knoepp; Wayne T. Swank

    1997-01-01

    Changes in surface soil C and N can result from forest management practices and may provide an index of impacts on long-term site productivity. Soil C and N were measured over time for five water- sheds in the southern Appalachians: two aggrading hardwood forests, one south- and one north-facing, undisturbed since the 1920s;a white pine (PinussfrobusL.) plantation...

  2. Carbon transfer from plant roots to soil - NanoSIMS analyses of undisturbed rhizosphere samples

    Science.gov (United States)

    Vidal, Alix; Hirte, Juliane; Bender, S. Franz; Mayer, Jochen; Gattinger, Andreas; Mueller, Carsten W.

    2017-04-01

    Soils are composed of a wide diversity of organic and mineral compounds, interacting to form complex mosaics of microenvironments. Roots and microorganisms are both key sources of organic carbon (OC). The volume of soil around living roots, i.e. the rhizosphere, is a privileged area for soil microbial activity and diversity. The microscopic observation of embedded soil sections has been applied since the 1950´s and has enabled observation of the rhizosphere at the smallest scale of organism interaction, i.e. at the level of root cells and bacteria (Alexander and Jackson, 1954). However, the observation of microorganisms in their intact environment, especially in soil, remains challenging. Existing microscopic images do not provide clear evidence of the chemical composition of compounds observed in the rhizosphere. Nano-scale secondary ion mass spectrometry (NanoSIMS) is a high spatial resolution method providing elemental and isotopic maps of organic and mineral materials. This technic has been increasingly used in soil science during the last decade (Hermann et al., 2007; Vogel et al., 2014) and more specifically for undisturbed soil sample observations (Vidal et al., 2016). In the present study, NanoSIMS was used to illustrate the biological, physical and chemical processes occurring in the rhizosphere at the microscale. To meet this objective, undisturbed rhizosphere samples were collected from a field experiment in Switzerland where wheat plants were pulse-labelled with 99% 13C-CO2 in weekly intervals throughout the growing season and sampled at flowering. Samples were embedded, sectioned, polished and analyzed with NanoSIMS, obtaining secondary ion images of 12C, 13C, 12C14N, 16O, 31P16O2, and 32S. The δ13C maps were obtained thanks to 12C and 13C images. 13C labelled root cells were clearly distinguished on images and presented highly variable δ13C values. Labelled spots (soil particles, forming microaggregates tightly bound to root cells. Finally, some

  3. Growth and Collapse of a Resource System: an Adaptive Cycle of Change in Public Lands Governance and Forest Management in Alaska

    Directory of Open Access Journals (Sweden)

    Colin M. Beier

    2009-12-01

    Full Text Available Large-scale government efforts to develop resources for societal benefit have often experienced cycles of growth and decline that leave behind difficult social and ecological legacies. To understand the origins and outcomes of these failures of resource governance, scholars have applied the framework of the adaptive cycle. In this study, we used the adaptive cycle as a diagnostic approach to trace the drivers and dynamics of forest governance surrounding a boom-bust sequence of industrial forest management in one of the largest-scale resource systems in U.S. history: the Tongass National Forest in southeastern Alaska. Our application of the adaptive cycle combined a historical narrative tracing dynamics in political, institutional, and economic subsystems and a longitudinal analysis of an indicator of overall system behavior (timber harvests. We found that federal policies in concert with global market changes drove transformative change in both forest governance (policy making and forest management (practices, through creation and dissolution of subsidized long-term lease contracts. Evidence of the systemic resilience provided by these leases was found in the analysis of industry responses to market volatility before and after Tongass-specific federal reforms. Although the lease contracts stabilized the Tongass system for a period of time, they fostered a growing degree of rigidity that contributed to a severe industrial collapse and the subsequent emergence of complex social traps. Broader lessons from the Tongass suggest that large-scale changes occurred only when the nested economic and policy cycles were in coherence, and a systemic effort to minimize social and ecological variability ultimately resulted in catastrophic collapse of governance. This collapse resulted in a pervasive and challenging legacy that prevents Tongass reorganization and limits the adaptive capacity of the larger social-ecological system of southeastern Alaska

  4. Nitrate Leaching from Winter Cereal Cover Crops Using Undisturbed Soil-Column Lysimeters.

    Science.gov (United States)

    Meisinger, John J; Ricigliano, Kristin A

    2017-05-01

    Cover crops are important management practices for reducing nitrogen (N) leaching, especially in the Chesapeake Bay watershed, which is under total maximum daily load (TMDL) restraints. Winter cereals are common cool-season crops in the Bay watershed, but studies have not directly compared nitrate-N (NO-N) leaching losses from these species. A 3-yr cover crop lysimeter study was conducted in Beltsville, MD, to directly compare NO-N leaching from a commonly grown cultivar of barley ( L.), rye ( L.), and wheat ( L.), along with a no-cover control, using eight tension-drained undisturbed soil column lysimeters in a completely randomized design with two replicates. The lysimeters were configured to exclude runoff and to estimate NO-N leaching and flow-weighted NO-N concentration (FWNC). The temporal pattern of NO-N leaching showed a consistent highly significant ( < 0.001) effect of lower NO-N leaching with cover crops compared with no cover but showed only small and periodically significant ( < 0.05) effects among the cultivars of barley, rye, and wheat covers. Nitrate-N leaching was more affected by the quantity of establishment-season (mid-October to mid-December) precipitation than by cover crop species. For example, compared with no cover, winter cereal covers reduced NO-N leaching 95% in a dry year and 50% in wet years, with corresponding reductions in FWNC of 92 and 43%, respectively. These results are important for scientists, nutrient managers, and policymakers because they directly compare NO-N leaching from winter cereal covers and expand knowledge for developing management practices for winter cereals that can improve water quality and increase N efficiency in cropping systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  5. Retention and remobilization of stabilized silver nanoparticles in an undisturbed loamy sand soil.

    Science.gov (United States)

    Liang, Yan; Bradford, Scott A; Simunek, Jiri; Heggen, Marc; Vereecken, Harry; Klumpp, Erwin

    2013-01-01

    Column experiments were conducted with undisturbed loamy sand soil under unsaturated conditions (around 90% saturation degree) to investigate the retention of surfactant stabilized silver nanoparticles (AgNPs) with various input concentration (Co), flow velocity, and ionic strength (IS), and the remobilization of AgNPs by changing the cation type and IS. The mobility of AgNPs in soil was enhanced with decreasing solution IS, increasing flow rate and input concentration. Significant retardation of AgNP breakthrough and hyperexponential retention profiles (RPs) were observed in almost all the transport experiments. The retention of AgNPs was successfully analyzed using a numerical model that accounted for time- and depth-dependent retention. The simulated retention rate coefficient (k1) and maximum retained concentration on the solid phase (Smax) increased with increasing IS and decreasing Co. The high k1 resulted in retarded breakthrough curves (BTCs) until Smax was filled and then high effluent concentrations were obtained. Hyperexponential RPs were likely caused by the hydrodynamics at the column inlet which produced a concentrated AgNP flux to the solid surface. Higher IS and lower Co produced more hyperexponential RPs because of larger values of Smax. Retention of AgNPs was much more pronounced in the presence of Ca(2+) than K(+) at the same IS, and the amount of AgNP released with a reduction in IS was larger for K(+) than Ca(2+) systems. These stronger AgNP interactions in the presence of Ca(2+) were attributed to cation bridging. Further release of AgNPs and clay from the soil was induced by cation exchange (K(+) for Ca(2+)) that reduced the bridging interaction and IS reduction that expanded the electrical double layer. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, and correlations between released soil colloids and AgNPs indicated that some of the released AgNPs were associated with the released clay fraction.

  6. Alabama's forests, 2000

    Science.gov (United States)

    Andrew J. Hartsell; Tony G. Johnson

    2009-01-01

    The principle findings of the seventh forest survey of Alabama (2000) and changes that have occurred since the previous surveys are presented. Topics examined include forest area, ownership, forest-type groups, stand structure, basal area, timber volume, growth, removals, and mortality.

  7. Minnesota forest statistics, 1990.

    Science.gov (United States)

    Patrick D. Miles; Chung M. Chen

    1992-01-01

    The fifth inventory of Minnesota's forests reports 51.0 million acres of land, of which 16.7 million acres are forested. This bulletin presents statistical highlights and contains detailed tables of forest area, as well as timber volume, growth, removals, mortality, and ownership.

  8. Effectiveness of native arbuscular mycorrhiza on the growth of four tree forest species from the Santa Marta Mountain, Veracruz (Mexico

    Directory of Open Access Journals (Sweden)

    Yolanda Retama-Ortiz

    2017-05-01

    Full Text Available Aim of the study: The aim of this work was to isolate consortia of arbuscular mycorrhizal fungi (AMF associated to Liquidambar styraciflua in soils of the Santa Marta Mountain in Veracruz, and to select highly effective mycorrhizal consortia on promoting the growth of four tree forest species with economic and ecological importance. Area of study: Santa Marta Mountain, inside the buffer area of the Los Tuxtlas Biological Reserve in Veracruz (México. Materials and methods: Ten composite samples of rhizosphere soil were collected from L. styraciflua trees of 13-15 cm DBH (diameter at breast height. Roots were fixed in FAA solution to determine the mycorrhizal colonization percentage, the abundance of morphospecies, and its effectiveness in promoting the growth of L. styraciflua, Terminalia amazonia, Cordia alliodora, and Cojoba arborea. Soil physical and chemical characteristics were also analysed, and soil type recognition was performed with the Reference Base for Soil FAO-ISRIC World-SICS. Mycorrhizal colonization was determined by the method of clearing and staining roots with trypan blue; total percentage of colonization was estimated by the Linderman-Biermann method. Spores were extracted for counting and identifying morphospecies from each soil sample, those with more effectiveness were selected and inoculated in the four tree species, based upon a completely random design there were evaluated height, number of leaves, total dry weight and foliar area. Main results: Average mycorrhizal colonization percentage was 45% from natural conditions, samples one and four showed 80% of AMF-colonization. Average number of spores was 617 in 100 g-1 of dry soil. Forty-seven AMF-morphospecies were identified. After eight months significant differences were observed in root colonization, height, number of leaves, total dry weight, leaf area and foliar analysis of N5+, P5+ and K+ on plants inoculated with rhizosphere samples of L. styraciflua. Terminalia

  9. Effectiveness of native arbuscular mycorrhiza on the growth of four tree forest species from the Santa Marta Mountain, Veracruz (Mexico)

    International Nuclear Information System (INIS)

    Retama-Ortiz, Y.; Ávila-Bello, C.H.; Alarcón, A.; Ferrera-Cerrato, R.

    2017-01-01

    Aim of the study: The aim of this work was to isolate consortia of arbuscular mycorrhizal fungi (AMF) associated to Liquidambar styraciflua in soils of the Santa Marta Mountain in Veracruz, and to select highly effective mycorrhizal consortia on promoting the growth of four tree forest species with economic and ecological importance. Area of study: Santa Marta Mountain, inside the buffer area of the Los Tuxtlas Biological Reserve in Veracruz (México). Materials and methods: Ten composite samples of rhizosphere soil were collected from L. styraciflua trees of 13-15 cm DBH (diameter at breast height). Roots were fixed in FAA solution to determine the mycorrhizal colonization percentage, the abundance of morphospecies, and its effectiveness in promoting the growth of L. styraciflua, Terminalia amazonia, Cordia alliodora, and Cojoba arborea. Soil physical and chemical characteristics were also analysed, and soil type recognition was performed with the Reference Base for Soil FAO-ISRIC World-SICS. Mycorrhizal colonization was determined by the method of clearing and staining roots with trypan blue; total percentage of colonization was estimated by the Linderman-Biermann method. Spores were extracted for counting and identifying morphospecies from each soil sample, those with more effectiveness were selected and inoculated in the four tree species, based upon a completely random design there were evaluated height, number of leaves, total dry weight and foliar area. Main results: Average mycorrhizal colonization percentage was 45% from natural conditions, samples one and four showed 80% of AMF-colonization. Average number of spores was 617 in 100 g-1 of dry soil. Forty-seven AMF-morphospecies were identified. After eight months significant differences were observed in root colonization, height, number of leaves, total dry weight, leaf area and foliar analysis of N5+, P5+ and K+ on plants inoculated with rhizosphere samples of L. styraciflua. Terminalia amazonia and

  10. Effectiveness of native arbuscular mycorrhiza on the growth of four tree forest species from the Santa Marta Mountain, Veracruz (Mexico)

    Energy Technology Data Exchange (ETDEWEB)

    Retama-Ortiz, Y.; Ávila-Bello, C.H.; Alarcón, A.; Ferrera-Cerrato, R.

    2017-11-01

    Aim of the study: The aim of this work was to isolate consortia of arbuscular mycorrhizal fungi (AMF) associated to Liquidambar styraciflua in soils of the Santa Marta Mountain in Veracruz, and to select highly effective mycorrhizal consortia on promoting the growth of four tree forest species with economic and ecological importance. Area of study: Santa Marta Mountain, inside the buffer area of the Los Tuxtlas Biological Reserve in Veracruz (México). Materials and methods: Ten composite samples of rhizosphere soil were collected from L. styraciflua trees of 13-15 cm DBH (diameter at breast height). Roots were fixed in FAA solution to determine the mycorrhizal colonization percentage, the abundance of morphospecies, and its effectiveness in promoting the growth of L. styraciflua, Terminalia amazonia, Cordia alliodora, and Cojoba arborea. Soil physical and chemical characteristics were also analysed, and soil type recognition was performed with the Reference Base for Soil FAO-ISRIC World-SICS. Mycorrhizal colonization was determined by the method of clearing and staining roots with trypan blue; total percentage of colonization was estimated by the Linderman-Biermann method. Spores were extracted for counting and identifying morphospecies from each soil sample, those with more effectiveness were selected and inoculated in the four tree species, based upon a completely random design there were evaluated height, number of leaves, total dry weight and foliar area. Main results: Average mycorrhizal colonization percentage was 45% from natural conditions, samples one and four showed 80% of AMF-colonization. Average number of spores was 617 in 100 g-1 of dry soil. Forty-seven AMF-morphospecies were identified. After eight months significant differences were observed in root colonization, height, number of leaves, total dry weight, leaf area and foliar analysis of N5+, P5+ and K+ on plants inoculated with rhizosphere samples of L. styraciflua. Terminalia amazonia and

  11. Effect of water stress on seedling growth in two species with different abundances: the importance of Stress Resistance Syndrome in seasonally dry tropical forest

    Directory of Open Access Journals (Sweden)

    Wanessa Nepomuceno Ferreira

    2015-09-01

    Full Text Available ABSTRACTIn seasonally dry tropical forests, species carrying attributes of Stress Resistance Syndrome (SRS may have ecological advantages over species demanding high quantities of resources. In such forests, Poincianella bracteosa is abundant, while Libidibia ferrea has low abundance; therefore, we hypothesized that P. bracteosa has characteristics of low-resource species, while L. ferrea has characteristics of high-resource species. To test this hypothesis, we assessed morphological and physiological traits of seedlings of these species under different water regimes (100%, 70%, 40%, and 10% field capacity over 85 days. For most of the studied variables we observed significant decreases with increasing water stress, and these reductions were greater in L. ferrea. As expected, L. ferreamaximized their growth with increased water supply, while P. bracteosa maintained slower growth and had minor adjustments in biomass allocation, characteristics representative of low-resource species that are less sensitive to stress. We observed that specific leaf area, biomass allocation to roots, and root/shoot ratio were higher in L. ferrea, while biomass allocation to leaves and photosynthesis were higher in P. bracteosa. Results suggest that the attributes of SRS can facilitate high abundance of P. bracteosa in dry forest.

  12. Forest resources of the Hoosier National Forest, 2005

    Science.gov (United States)

    Christoper W. Woodall; Judith A. Perez; Thomas R. Thake

    2007-01-01

    The first annual inventory of the Hoosier National Forest reports more than 200,000 forest land acres dominated by oaks, maples, and hickories with annual growth exceeding annual mortality by a factor of seven. When compared to forests in the rest of Indiana, the Hoosier's forests are on average older, have greater biomass per acre, and possess a greater...

  13. The forest resources of the Hiawatha National Forest, 1993.

    Science.gov (United States)

    Thomas Schmidt; Mike Lanasa

    1995-01-01

    The inventory of the forest resources of Hiawatha National Forest reports 892.1 thousand acres of land, of which 756.7 thousand acres are forested. This bulletin presents statistical highlights and contains detailed tables of forest area, as well as of timber volume, growth, removals, and mortality.

  14. Factors responsible for co-dominance of two beech species in a cool temperate forest in central Japan: interspecific comparison of spatial distribution and growth traits

    Directory of Open Access Journals (Sweden)

    Wataru Ishizuka

    2012-06-01

    Full Text Available To understand the co-existence mechanisms of related species, the recruitment processes of Fagus crenata and F. japonica were censused during 3 and 4 years from emergence, respectively, in a cool-temperate forest in Japan. The distributional properties and the growth traits were compared between two Fagus species. To evaluate the distributional properties, the spatial abundance of seedlings was estimated by a generalized linear model (GLM, with explanatory variables such as topographic variables, light conditions, the presence of dwarf bamboo, and the abundance of the overstory. To evaluate the growth traits under herbivory pressure, both the elongated shoot length and the proportion of recovery from predation (re-growth were also compared. No spatial segregation and no species-specific differences were detected by GLM, which was consistent throughout the census period. Only F. japonica exhibited a slope-related distribution, while F. crenata exhibited no topographical dependence, indicates the distributional overlaps. For the growth traits, contrasting trends were detected, F. crenata was superior in shoot growth, whereas the proportion of re-growth was higher in F. japonica than F. crenata. We concluded that co-dominance of these species was not attributed to the spatial segregation but to the trade-off between growth and resistance to herbivory.

  15. Seasonal and inter-annual dynamics of growth, non-structural carbohydrates and C stable isotopes in a Mediterranean beech forest.

    Science.gov (United States)

    Scartazza, Andrea; Moscatello, Stefano; Matteucci, Giorgio; Battistelli, Alberto; Brugnoli, Enrico

    2013-07-01

    Seasonal and inter-annual dynamics of growth, non-structural carbohydrates (NSC) and carbon isotope composition (δ(13)C) of NSC were studied in a beech forest of Central Italy over a 2-year period characterized by different environmental conditions. The net C assimilated by forest trees was mainly used to sustain growth early in the season and to accumulate storage carbohydrates in trunk and root wood in the later part of the season, before leaf shedding. Growth and NSC concentration dynamics were only slightly affected by the reduced soil water content (SWC) during the drier year. Conversely, the carbon isotope analysis on NSC revealed seasonal and inter-annual variations of photosynthetic and post-carboxylation fractionation processes, with a significant increase in δ(13)C of wood and leaf soluble sugars in the drier summer year than in the wetter one. The highly significant correlation between δ(13)C of leaf soluble sugars and SWC suggests a decrease of the canopy C isotope discrimination and, hence, an increased water-use efficiency with decreasing soil water availability. This may be a relevant trait for maintaining an acceptable plant water status and a relatively high C sink capacity during dry seasonal periods. Our results suggest a short- to medium-term homeostatic response of the Collelongo beech stand to variations in water availability and solar radiation, indicating that this Mediterranean forest was able to adjust carbon-water balance in order to prevent C depletion and to sustain plant growth and reserve accumulation during relatively dry seasons.

  16. Forest nutrient and carbon pools at Walker Branch watershed: changes during a 21-year period

    Science.gov (United States)

    Carl C. Trettin; D.W. Johnson; D.E. Todd

    1999-01-01

    A 21-yr perspective on changes in nutrient and C pools on undisturbed upland forest sites is provided. Plots originally representing four cover types have been sampled three times. On each plot, forest biomass, forest floor, and soil, to a depth of 60 cm, were measured, sampled, and analyzed for Ca, Mg, C, N, and P. Exchangeable soil Ca and Mg have declined in most...

  17. DIVERSITY, ANTIMICROBIAL ACTIVITIES AND ASSOCIATED MICROBIOTA OF SOIL PENICILLIA FROM VIRGIN FOREST FLOOR

    OpenAIRE

    G.U. Ahmed; M. Chutia

    2012-01-01

    The diversity of Penicillium spp. and associate mycobiota from different virgin forest floor in the Brahmaputra Valley, Assam, India was analyzed. Soil samples were collected from six different undisturbed forest floors together with seasonally flooded forest and also from agricultural fields. Samples were taken from the litter and from three soil core i.e. 0-5, 10-15 and 30-35 cm in depth. The isolated fungal species were identified based on morphological and reproductive characteristics. Ab...

  18. The changing Amazon forest

    OpenAIRE

    Phillips, Oliver L; Lewis, Simon L; Baker, Timothy R; Chao, Kuo-Jung; Higuchi, Niro

    2008-01-01

    Long-term monitoring of distributed, multiple plots is the key to quantify macroecological patterns and changes. Here we examine the evidence for concerted changes in the structure, dynamics and composition of old-growth Amazonian forests in the late twentieth century. In the 1980s and 1990s, mature forests gained biomass and underwent accelerated growth and dynamics, all consistent with a widespread, long-acting stimulation of growth. Because growth on average exceeded mortality, intact Amaz...

  19. Epiphytic lichens of Stužica (E Slovakia) in the context of Central European old-growth forests

    Czech Academy of Sciences Publication Activity Database

    Vondrák, Jan; Malíček, J.; Šoun, J.; Pouska, V.

    2015-01-01

    Roč. 28, č. 1 (2015), s. 104-126 ISSN 0018-0971 Institutional support: RVO:67985939 Keywords : beech forest * diversity inventory * Sorensen's similarity index Subject RIV: EF - Botanics Impact factor: 0.821, year: 2015

  20. Searching for indicator species of old-growth spruce forests: studies in the genus Jahnoporus (Polyporales, Basidiomycota)

    Czech Academy of Sciences Publication Activity Database

    Spirin, V.; Vlasák, Josef; Milakovsky, B.; Miettinen, O.

    2015-01-01

    Roč. 36, č. 4 (2015), s. 409-417 ISSN 0181-1584 Institutional support: RVO:60077344 Keywords : Forest conservation * polypores * wood-rotting fungi Subject RIV: EF - Botanics Impact factor: 1.509, year: 2015

  1. High retention of 15N-labeled nitrogen deposition in a nitrogen saturated old-growth tropical forest

    DEFF Research Database (Denmark)

    Gurmesa, Geshere Abdisa; Lu, Xiankai; Gundersen, Per

    2016-01-01

    The effects of increased reactive nitrogen (N) deposition in forests depend largely on its fate in the ecosystems. However, our knowledge on the fates of deposited N in tropical forest ecosystems and its retention mechanisms is limited. Here, we report the results from the first whole ecosystem (15...... ecosystem compartments were quantified 4 months after the last addition. Tracer recoveries in soil solution were monitored monthly to quantify leaching losses. Total tracer recovery in plant and soil (N retention) in the control plots was 72% and similar to those observed in temperate forests. The retention...... soil. Nitrogen addition increased N leaching to 73 kg N ha(-1) yr(-1) . However, of these only 7 and 23 kg N ha(-1) yr(-1) in the control and N-plots, respectively, originated from the labeled N input. Our findings indicate that deposited N, like in temperate forests, is largely incorporated into plant...

  2. Quantitative imaging of the 3-D distribution of cation adsorption sites in undisturbed soil

    Science.gov (United States)

    Keck, Hannes; Strobel, Bjarne W.; Petter Gustafsson, Jon; Koestel, John

    2017-10-01

    Several studies have shown that the distribution of cation adsorption sites (CASs) is patchy at a millimetre to centimetre scale. Often, larger concentrations of CASs in biopores or aggregate coatings have been reported in the literature. This heterogeneity has implications on the accessibility of CASs and may influence the performance of soil system models that assume a spatially homogeneous distribution of CASs. In this study, we present a new method to quantify the abundance and 3-D distribution of CASs in undisturbed soil that allows for investigating CAS densities with distance to the soil macropores. We used X-ray imaging with Ba2+ as a contrast agent. Ba2+ has a high adsorption affinity to CASs and is widely used as an index cation to measure the cation exchange capacity (CEC). Eight soil cores (approx. 10 cm3) were sampled from three locations with contrasting texture and organic matter contents. The CASs of our samples were saturated with Ba2+ in the laboratory using BaCl2 (0.3 mol L-1). Afterwards, KCl (0.1 mol L-1) was used to rinse out Ba2+ ions that were not bound to CASs. Before and after this process the samples were scanned using an industrial X-ray scanner. Ba2+ bound to CASs was then visualized in 3-D by the difference image technique. The resulting difference images were interpreted as depicting the Ba2+ bound to CASs only. The X-ray image-derived CEC correlated significantly with results of the commonly used ammonium acetate method to determine CEC in well-mixed samples. The CEC of organic-matter-rich samples seemed to be systematically overestimated and in the case of the clay-rich samples with less organic matter the CEC seemed to be systematically underestimated. The results showed that the distribution of the CASs varied spatially within most of our samples down to a millimetre scale. There was no systematic relation between the location of CASs and the soil macropore structure. We are convinced that the approach proposed here will strongly

  3. Growth and yield of Solanum khasianum in Pinus roxburghii forest based silvi-medicinal system in mid hills of Indian Himalaya

    Directory of Open Access Journals (Sweden)

    Chandra Shekher Sanwal

    2016-08-01

    Full Text Available Background In mid hills of Western Himalayas, Himachal Pradesh India, growth, yield and economics of Solanum khasianum as a potential medicinal herb under Pinus roxburghii (Chir pine plantation has been studied for two consecutive years to assess the performance of Solanum khasianum in undercanopy of Pinus roxburghii for developing Solanum khasianum and Pinus roxburghii based innovative silvi-medicinal system. Methods Growth parameters such as plant height, number of branches per plant and leaf area index followed by yield were estimated after Solanum khasianum was grown on three topographical aspects as; Northern, North - western and Western at a spacing of 45 cm × 45 cm, followed by three tillage depths as; minimum (0 cm, medium (up to 10 cm and deep tillage (up to 15 cm, in open and below canopy conditions treatment. The study was conducted to explore the possibility of using Solanum khasianum based silvi-medicinal system to utilize the below canopy of Chir pine forest for enhancing the productivity of forests besides the conservation of the medicinal herb. Results The growth parameters such as plant height, number of branches per plant and leaf area index were non-significantly affected by topographical aspects and tillage practices, both below canopy and open conditions except fresh weight and dry weight of berries during harvesting stage. The maximum yield (0.61 t∙ha−1 was observed on Western aspect in open conditions as compared to below canopy of Chir pine. The highest gross returns were observed for the crop cultivated on Western aspect under deep tillage in open conditions than other aspect and tillage combinations. However the positive net returns from the crops raised in below canopy of Chir pine indicates its possible economic viability under agroforestry system as the gross returns was higher than the cost of cultivation. Conclusion Solanum khasianum when grown in below canopy of Pinus roxburghii, its growth and yield

  4. Factors responsible for co-dominance of two beech species in a cool temperate forest in central Japan: interspecific comparison of spatial distribution and growth traits

    Directory of Open Access Journals (Sweden)

    Wataru Ishizuka

    2012-05-01

    Full Text Available To understand the co-existence mechanisms of related species,the recruitment processes of Fagus crenata and F. japonica were censused during 3 and 4 years from emergence, respectively, in a cool-temperate forest in Japan. The distributional properties and the growth traits were compared between two Fagus species. To evaluate the distributional properties, the spatial abundance of seedlings was estimated by a generalized linear model (GLM, with explanatory variables such as topographic variables, light conditions, the presence of dwarf bamboo, and the abundance of the overstory. To evaluate the growth traits under herbivory pressure, both the elongated shoot length and the proportion of recovery frompredation (re-growth were also compared. No spatial segregation and no species-specific differences were detected by GLM, which was consistent throughout the census period. Only F. japonica exhibited a slope-related distribution, while F. crenata exhibited no topographical dependence, indicates the distributional overlaps. For the growth traits, contrasting trends were detected, F. crenata was superior in shoot growth, whereas the proportion of regrowth was higher in F. japonica than F. crenata. We concluded that co-dominance of these species was not attributed to the spatial segregationbut to the trade-off between growth and resistance to herbivory.

  5. Long-term growth-increment chronologies reveal diverse influences of climate forcing on freshwater and forest biota in the Pacific Northwest

    Science.gov (United States)

    Black, Bryan A.; Dunham, Jason B.; Blundon, Brett W.; Brim-Box, Jayne; Tepley, Alan J.

    2015-01-01

    Analyses of how organisms are likely to respond to a changing climate have focused largely on the direct effects of warming temperatures, though changes in other variables may also be important, particularly the amount and timing of precipitation. Here, we develop a network of eight growth-increment width chronologies for freshwater mussel species in the Pacific Northwest, United States and integrate them with tree-ring data to evaluate how terrestrial and aquatic indicators respond to hydroclimatic variability, including river discharge and precipitation. Annual discharge averaged across water years (October 1–September 30) was highly synchronous among river systems and imparted a coherent pattern among mussel chronologies. The leading principal component of the five longest mussel chronologies (1982–2003; PC1mussel) accounted for 47% of the dataset variability and negatively correlated with the leading principal component of river discharge (PC1discharge; r = −0.88; P nature of the relationships varied across the landscape. Negative correlations occurred in forests where tree growth tends to be limited by drought while positive correlations occurred in forests where tree growth tends to be limited by deep or lingering snowpack. Overall, this diverse assemblage of chronologies illustrates the importance of winter precipitation to terrestrial and freshwater ecosystems and suggests that a complexity of climate responses must be considered when estimating the biological impacts of climate variability and change.

  6. Evaluation of Whole Tree Growth Increment Derived from Tree-Ring Series for Use in Assessments of Changes in Forest Productivity across Various Spatial Scales

    Directory of Open Access Journals (Sweden)

    Juha M. Metsaranta

    2016-12-01

    Full Text Available The inherent predictability of inter-annual variation in forest productivity remains unknown. Available field-based data sources for understanding this variability differ in their spatial resolution, temporal resolution, and typical units of measure. Nearly all other tree and forest characteristics are in practice derived from measurements of diameter at breast height (DBH. Therefore, diameter increment reconstructed annually from tree-ring data can be used to estimate annual growth increments of wood volume, but the accuracy and precision of these estimates requires assessment. Annual growth estimates for n = 170 trees sampled for whole stem analysis from five tree species (jack pine, lodgepole pine, black spruce, white spruce, and trembling aspen in Western Canada were compared against increments derived from breast height measurements only. Inter-annual variability of breast height and whole tree growth increments was highly correlated for most trees. Relative errors varied by species, diameter class, and the equation used to estimate volume (regional vs. national. A simple example of the possible effect of this error when propagated to the stand level is provided.

  7. Stand basal-area and tree-diameter growth in red spruce-fir forests in Maine, 1960-80

    Science.gov (United States)

    S.J. Zarnoch; D.A. Gansner; D.S. Powell; T.A. Birch; T.A. Birch

    1990-01-01

    Stand basal-area change and individual surviving red spruce d.b.h. growth from 1960 to 1980 were analyzed for red spruce-fir stands in Maine. Regression modeling was used to relate these measures of growth to stand and tree conditions and to compare growth throughout the period. Results indicate a decline in growth.

  8. Global carbon impacts of using forest harvest residues for district heating in Vermont

    International Nuclear Information System (INIS)

    McLain, H.A.

    1998-01-01

    Forests in Vermont are selectively logged periodically to generate wood products and useful energy. Carbon remains stored in the wood products during their lifetime and in fossil fuel displaced by using these products in place of energy-intensive products. Additional carbon is sequestered by new forest growth, and the forest inventory is sustained using this procedure. A significant portion of the harvest residue can be used as biofuel in central plants to generate electricity and thermal energy, which also displaces the use of fossil fuels. The impact of this action on the global carbon balance was analyzed using a model derived from the Graz/Oak Ridge Carbon Accounting Model (GORCAM). The analysis showed that when forests are harvested only to manufacture wood products, more than 100 years are required to match the sequestered carbon present if the forest is left undisturbed. If part of the harvest residue is collected and used as biofuel in place of oil or natural gas, it is possible to reduce this time to about 90 years, but it is usually longer. Given that harvesting the forest for products will continue, carbon emission benefits relative to this practice can start within 10 to 70 years if part of the harvest residue is used as biofuel. This time is usually higher for electric generation plants, but it can be reduced substantially by converting to cogeneration operation. Cogeneration makes possible a ratio of carbon emission reduction for district heating to carbon emission increase for electricity generation in the range of 3 to 5. Additional sequestering benefits can be realized by using discarded wood products as biofuels

  9. Negative impacts of high temperatures on growth of black spruce forests intensify with the anticipated climate warming.

    Science.gov (United States)

    Girardin, Martin P; Hogg, Edward H; Bernier, Pierre Y; Kurz, Werner A; Guo, Xiao Jing; Cyr, Guillaume

    2016-02-01

    An increasing number of studies conclude that water limitations and heat stress may hinder the capacity of black spruce (Picea mariana (Mill.) B.S.P.) trees, a dominant species of Canada's boreal forests, to grow and assimilate atmospheric carbon. However, there is currently no scientific consensus on the future of these forests over the next century in the context of widespread climate warming. The large spatial extent of black spruce forests across the Canadian boreal forest and associated variability in climate, demography, and site conditions pose challenges for projecting future climate change responses. Here we provide an evaluation of the impacts of climate warming and drying, as well as increasing [CO2 ], on the aboveground productivity of black spruce forests across Canada south of 60°N for the period 1971 to 2100. We use a new extensive network of tree-ring data obtained from Canada's National Forest Inventory, spatially explicit simulations of net primary productivity (NPP) and its drivers, and multivariate statistical modeling. We found that soil water availability is a significant driver of black spruce interannual variability in productivity across broad areas of the western to eastern Canadian boreal forest. Interannual variability in productivity was also found to be driven by autotrophic respiration in the warmest regions. In most regions, the impacts of soil water availability and respiration on interannual variability in productivity occurred during the phase of carbohydrate accumulation the year preceding tree-ring formation. Results from projections suggest an increase in the importance of soil water availability and respiration as limiting factors on NPP over the next century due to warming, but this response may vary to the extent that other factors such as carbon dioxide fertilization, and respiration acclimation to high temperature, contribute to dampening these limitations. © 2015 Her Majesty the Queen in Right of Canada. Reproduced with

  10. Extreme late-summer drought causes neutral annual carbon balance in southwestern ponderosa pine forests and grasslands

    International Nuclear Information System (INIS)

    Kolb, Thomas; Dore, Sabina; Montes-Helu, Mario

    2013-01-01

    We assessed the impacts of extreme late-summer drought on carbon balance in a semi-arid forest region in Arizona. To understand drought impacts over extremes of forest cover, we measured net ecosystem production (NEP), gross primary production (GPP), and total ecosystem respiration (TER) with eddy covariance over five years (2006–10) at an undisturbed ponderosa pine (Pinus ponderosa) forest and at a former forest converted to grassland by intense burning. Drought shifted annual NEP from a weak source of carbon to the atmosphere to a neutral carbon balance at the burned site and from a carbon sink to neutral at the undisturbed site. Carbon fluxes were particularly sensitive to drought in August. Drought shifted August NEP at the undisturbed site from sink to source because the reduction of GPP (70%) exceeded the reduction of TER (35%). At the burned site drought shifted August NEP from weak source to neutral because the reduction of TER (40%) exceeded the reduction of GPP (20%). These results show that the lack of forest recovery after burning and the exposure of undisturbed forests to late-summer drought reduce carbon sink strength and illustrate the high vulnerability of forest carbon sink strength in the southwest US to predicted increases in intense burning and precipitation variability. (letter)

  11. Differential growth responses to water balance of coexisting deciduous tree species are linked to wood density in a Bolivian tropical dry forest.

    Directory of Open Access Journals (Sweden)

    Hooz A Mendivelso

    Full Text Available A seasonal period of water deficit characterizes tropical dry forests (TDFs. There, sympatric tree species exhibit a diversity of growth rates, functional traits, and responses to drought, suggesting that each species may possess different strategies to grow under different conditions of water availability. The evaluation of the long-term growth responses to changes in the soil water balance should provide an understanding of how and when coexisting tree species respond to water deficit in TDFs. Furthermore, such differential growth responses may be linked to functional traits related to water storage and conductance. We used dendrochronology and climate data to retrospectively assess how the radial growth of seven coexisting deciduous tree species responded to the seasonal soil water balance in a Bolivian TDF. Linear mixed-effects models were used to quantify the relationships between basal area increment and seasonal water balance. We related these relationships with wood density and sapwood production to assess if they affect the growth responses to climate. The growth of all species responded positively to water balance during the wet season, but such responses differed among species as a function of their wood density. For instance, species with a strong growth response to water availability averaged a low wood density which may facilitate the storage of water in the stem. By contrast, species with very dense wood were those whose growth was less sensitive to water availability. Coexisting tree species thus show differential growth responses to changes in soil water balance during the wet season. Our findings also provide a link between wood density, a trait related to the ability of trees to store water in the stem, and wood formation in response to water availability.

  12. The response of soil carbon cycling in managed loblolly pine forests to fertilization and the planting of families with differing growth rates

    Science.gov (United States)

    Vogel, J. G.; Schuur, E. A.; Gill, C.; Bracho, R.; Jokela, E.

    2010-12-01

    Forest management practices in the southern United States have made the pine forests of the region some of the most productive in the world. This remarkable productivity makes the region attractive for offsetting anthropogenic emissions of CO2 through increased biomass capture, or through the biomass-to-fuel approach. In other agricultural systems, however, increased plant productivity from management has often corresponded to a decrease in soil carbon. Over half of a forest ecosystem’s carbon is found in the soil; therefore a decrease in soil carbon could counteract a considerable amount of the reduction in atmospheric CO2 that results from enhanced tree growth. We have examined two forestry practices, fertilization with nitrogen and phosphorus and the genetic control of planted seedlings, in terms of how these practices affect key controls on soil carbon cycling. Root biomass dynamics, soil CO2 efflux, and microbial respiration were contrasted for a “fast” and a “slow” growing family of loblolly pine receiving two different levels of fertilization at two sites in north central Florida. Our overarching hypothesis was that greater aboveground growth would correspond to increased inputs of carbon to the soil as root biomass, and a greater efflux of CO2 from roots and soil microbes. At both sites, the faster growing families supported significantly (pfamilies. However under higher levels of fertilization, the fast and the slow growing families had similar levels of fine root biomass and soil CO2 efflux. Results from this study suggest that greater aboveground growth due to genetic selection only related to greater inputs of carbon to the soil when fertilization levels were low. Radiocarbon measurements of microbial respiration indicated no differences in soil organic matter turnover among families or fertilization treatments. These results suggest that the response to management of soil carbon will be more sensitive to how fertilization or genetic selection

  13. Long-term persistence of pioneer species in tropical forest soil seed banks

    Energy Technology Data Exchange (ETDEWEB)

    Dalling, J W; Brown, T A

    2008-10-05

    In tropical forests, pioneer species regenerate from seeds dispersed directly into canopy gaps, and from seeds that persisted in soil seed banks before gap formation. However, life-history models suggest that selection for long-term persistence of seeds in soil should be weak, as persistence incurs a fitness cost resulting from prolonged generation time. We use a carbon dating technique to provide the first direct measurements of seed persistence in undisturbed tropical forest seed banks. We show that seeds germinate successfully from surface soil microsites up to 38 years after dispersal. Decades-long persistence may be common in pioneers with relatively large mass, and appears to be unrelated to specific regeneration requirements. In Croton billbergianus, a sub-canopy tree that recruits in abundant small gaps, long-term persistence is associated with short-distance ballistic seed dispersal. In Trema micrantha, a canopy tree with widespread dispersal, persistence is associated with a requirement for large gaps that form infrequently in old-growth forest.

  14. Low Light Availability Associated with American Beech Is the Main Factor for Reduced Sugar Maple Seedling Survival and Growth Rates in a Hardwood Forest of Southern Quebec

    Directory of Open Access Journals (Sweden)

    Alexandre Collin

    2017-10-01

    Full Text Available Several recent studies have reported a marked increase in American beech dominance (Fagus grandifolia Ehrh. relative to sugar maple (Acer saccharum Marsh. in late successional forests of North America. However, many factors have been proposed to explain this sudden shift in tree species composition. We investigated the microsite factors responsible for maple regeneration failure under maple-beech stands, focusing on both light availability and soil conditions. The survival and growth of maple seedlings planted in the natural soil and in pots with enriched soil were monitored for two years, as well as foliar nutrition and herbivory damages of natural seedlings. The results indicate that low light availability associated with the presence of beech is the primary factor leading to maple regeneration failures. Soil nutrient availability and foliar nutrition of natural seedlings did not differ between forest types. Yet, the results indicate that factors such as allelopathy and preferential herbivory on maple seedlings under beech could be superimposed effects that hinder maple regeneration. Under similar forests, a control of beech sapling abundance in the understory followed by selection cutting could be one way to promote and maintain maple populations in the longer term.

  15. Topography and age mediate the growth responses of Smith fir to climate warming in the southeastern Tibetan Plateau.

    Science.gov (United States)

    Liu, B; Wang, Y; Zhu, H; Liang, E; Camarero, J J

    2016-10-01

    The Tibetan Plateau holds some of the world's highest undisturbed natural treelines and timberlines. Such extreme environments constitute potentially valuable monitoring sites of the effects of climate warming on high-elevation forests. Here, we analyze a network of 21 Smith fir forests situated in the Sygera Mountains, southeastern Tibetan Plateau, using tree-ring width (TRW) and basal area increment (BAI) chronologies. Sampled sites encompassed a wide elevation gradient, from 3600 to 4400 m, including some treeline sites and diverse aspects and tree ages. In comparison with TRW series, BAI series better capture the long-term warming signal. Previous November and current April and summer temperatures are the dominant climatic factors controlling Smith fir radial growth. The mean inter-series correlations of TRW increased upwards, but the forest limit presented the highest potential to reconstruct past temperature variability. Moreover, the growth responses of young trees were less stable than those of trees older than 100 years. Climate warming is accelerating radial growth of Smith fir forest subjected to mesic conditions. Collectively, these findings confirm that the effects of site elevation and tree age should be considered when quantifying climate-growth relationships. The type of tree-ring data (BAI vs. TRW) is also relevant since BAI indices seem to be a better climatic proxy of low-frequency temperature signals than TRW indices. Therefore, site (e.g., elevation) and tree (e.g., age) features should be considered to properly evaluate the effects of climate warming on growth of high-elevation forests.

  16. Tree growth and competition in a post-logging Quercus mongolica forest on Mt. Sobaek, South Korea

    Czech Academy of Sciences Publication Activity Database

    Doležal, Jiří; Song, J. S.; Altman, J.; Janeček, Štěpán; Černý, Tomáš; Šrůtek, Miroslav; Kolbek, Jiří

    2009-01-01

    Roč. 24, - (2009), s. 281-290 ISSN 0912-3814 R&D Projects: GA ČR GA206/05/0119 Institutional research plan: CEZ:AV0Z60050516 Keywords : Deciduous forests * stand recovery * spontaneous development Subject RIV: EF - Botanics Impact factor: 1.485, year: 2009

  17. Evaluating relationships among tree growth rate, shade tolerance, and browse tolerance following disturbance in an eastern deciduous forest

    Science.gov (United States)

    Lisa M. Krueger; Chris J. Peterson; Alejandro Royo; Walter P. Carson

    2009-01-01

    Interspecific differences in shade tolerance among woody species are considered a primary driving force underlying forest succession. However, variation in shade tolerance may be only one of many interspecific differences that cause species turnover. For example, tree species may differ in their sensitivity to herbivory. Nonetheless,...

  18. Chromosera cyanophylla (Basidiomycota, Agaricales) a rare fungus of Central European old-growth forests and its habitat preferences in Europe

    Czech Academy of Sciences Publication Activity Database

    Holec, J.; Kříž, M.; Beran, M.; Kolařík, Miroslav

    2015-01-01

    Roč. 100, 1-2 (2015), s. 189-204 ISSN 0029-5035 Institutional support: RVO:61388971 Keywords : Omphalina cyanophylla * Boubinskyr prales virgin forest * Czech Republic Subject RIV: EE - Microbiology, Virology Impact factor: 0.876, year: 2015

  19. Establishment and growth of white spruce on a boreal forest floodplain: interactions between microclimate and mammalian herbivory

    Science.gov (United States)

    Amy C. Angell; Knut. Kielland

    2009-01-01

    White spruce (Picea glauca (Moench) Voss) is a dominant species in late-successional ecosystems along the Tanana River, interior Alaska, and the most important commercial timber species in these boreal floodplain forests. Whereas white spruce commonly seed in on young terraces in early primary succession, the species does not become a conspicuous...

  20. The effects of forest residual debris disposal on perennial grass emergence, growth, and survival in a ponderosa pine ecotone

    Science.gov (United States)

    Darin J. Law; Peter F. Kolb

    2007-01-01

    Soil surface conditions can have profound effects on plant seedling emergence and subsequent seedling survival. To test the hypothesis that different soil-surface treatments with logging residue affect range grass seedling emergence and survival, 6 alternative forest-residual treatments were established in the summer of 1998 following thinning of mature trees from...

  1. New and interesting lichen records from old-growth forest stands in the German National Park Bayerischer Wald

    Czech Academy of Sciences Publication Activity Database

    Printzen, C.; Halda, J.; Palice, Zdeněk; Toensberg, T.

    2002-01-01

    Roč. 74, 1-2 (2002), s. 25-49 ISSN 0029-5035 R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6005908 Keywords : lichens * forest stands * Bayerischer Wald National Park Subject RIV: EF - Botanics Impact factor: 0.588, year: 2002

  2. Alternatives to clearcutting in the old-growth forests of southeast Alaska: study plan and establishment report.

    Science.gov (United States)

    Michael H. McClellan; Douglas N. Swanston; Paul E. Hennon; Robert L. Deal; Toni L. de Santo; Mark S. Wipfli

    2000-01-01

    Much is known about the ecological effects, economics, and social impacts of clearcutting, but little documented experience with other silvicultural systems exists in southeast Alaska. The Pacific Northwest Research Station and the Alaska Region of the USDA Forest Service have cooperatively established an interdisciplinary study of ecosystem and social responses to...

  3. Tree growth, foliar chemistry, and nitrogen cycling across a nitrogen deposition gradient in southern Appalachian deciduous forests

    Science.gov (United States)

    Johnny L. Boggs; Steven G. McNulty; Michael J. Gavazzi; Jennifer Moore Myers

    2005-01-01

    The declining health of high-elevation red spruce (Picea rubens Sarg.) and Fraser fir (Abies fraseri (Pursh) Poir.) in the southern Appalachian region has long been linked to nitrogen (N)deposition. Recently, N deposition has also been proposed as a source of negative health impacts in lower elevation deciduous forests. In 1998 we...

  4. Evidences from long-term monitoring of Italian forests. Tree radial growth as response index to disturbances and its relations with the stand structure

    Directory of Open Access Journals (Sweden)

    Bertini G

    2013-09-01

    Full Text Available The paper deals with the work undertaken since 1995 within the national level II network framed into the ICP-Forests ICP-IM programme. A synthesis of results from tree growth monitoring and relationships with stand structure and related parameters, are reported. Current changes in the growth medium, i.e. physics and chemistry of atmosphere and soil, (increase of average air temperature, rainfall shortage and drought, CO2 enrichment, ozone level, nitrogen fertilization, sulphate deposition drive today the soil-tree-atmosphere relationships. The overall result of these concurrent and counteracting factors is recorded along each growing seasons by radial stem growth, it providing a sensitive response. A few occurrences of disturbances to growth at regional and at case-study level, likely due to climate deviations, are discussed. Seasonal fluctuations and anomalous or extreme events are, as a matter of fact, the major evidences over the last decade. The heat wave 2003 is the main case occurred over a large part of Europe. Growth rate 2000-04 compared with 1997-2000, showed reductions up to 50% on plots located within the Southern continental border of the heat wave. These occurred more specifically at low elevations and for pre-determined early growth species (beech and oaks. Over the following time-window 2005-09, a significant growth decrease was vice versa detected within the coniferous spruce forests located at medium-high elevation in the Alps, where repeated seasonal anomalies both in air temperature and rainfall were recorded over the same time-span. The heavy effect of climate disturbance at a local scale is finally examined where two oak species with different auto-ecology grow together at the same site. Reasons why and awaited goals from protocols’ updating and the more intensive surveys applied to core-areas in 2009-10 under LIFE+FutMon, are reported. Perspectives at short to medium term of monitoring programme at national and European

  5. Contrasting secondary growth and water-use efficiency patterns in native and exotic trees co-occurring in inner Spain riparian forests

    Directory of Open Access Journals (Sweden)

    Noelia González-Muñoz

    2015-04-01

    Full Text Available Aim of study: The invasive trees Ailanthus altissima and Robinia pseudoacacia are widely spreading in inner Spain riparian forests, where they co-occur with the natives Fraxinus angustifolia and Ulmus minor. In a climate change context, we aimed to identify some of the species traits that are leading these species to success (Basal Area Increment (BAI and water-use efficiency (iWUE. We also aimed to describe the main environmental variables controlling studied species BAI. Area of study: Riparian forests of central Spain Material and Methods: We measured tree-ring width and converted it to basal area increment (BAI; intrinsic water-use efficiency (iWUE was estimated from tree ring carbon isotopes (δ13C. We compared the BAI and iWUE of the last 20 years between origins (native vs exotic and among species. For each species, we evaluated iWUE and BAI relationships. Linear mixed-effect models were performed to identify the main environmental variables (temperature, precipitation, river flow affecting BAI. Main result: Native trees showed higher mean BAI than invaders, mainly due to the rising growth rate of U. minor. Invaders showed higher mean iWUE than natives. We did not find significant correlations between iWUE and BAI in any case. Warm temperatures in autumn positively affected the BAI of the natives, but negatively that of the invaders. Research highlights: The contrasting effect of autumn temperatures on native and invasive species BAI suggests that invaders will be more hampered by the rising temperatures predicted for this century. The higher iWUE found for the invaders did not translate into increased radial growth, suggesting that drought stress may have prevented them of taking advantage of increased atmospheric CO2 for a faster growth. These findings point out that neither climate change nor rising CO2 seem to enhance the success of study invasive species over the natives in riparian forests of central Spain. Furthermore, the low BAI

  6. An imputation/copula-based stochastic individual tree growth model for mixed species Acadian forests: a case study using the Nova Scotia permanent sample plot network

    Directory of Open Access Journals (Sweden)

    John A. KershawJr

    2017-09-01

    Full Text Available Background A novel approach to modelling individual tree growth dynamics is proposed. The approach combines multiple imputation and copula sampling to produce a stochastic individual tree growth and yield projection system. Methods The Nova Scotia, Canada permanent sample plot network is used as a case study to develop and test the modelling approach. Predictions from this model are compared to predictions from the Acadian variant of the Forest Vegetation Simulator, a widely used statistical individual tree growth and yield model. Results Diameter and height growth rates were predicted with error rates consistent with those produced using statistical models. Mortality and ingrowth error rates were higher than those observed for diameter and height, but also were within the bounds produced by traditional approaches for predicting these rates. Ingrowth species composition was very poorly predicted. The model was capable of reproducing a wide range of stand dynamic trajectories and in some cases reproduced trajectories that the statistical model was incapable of reproducing. Conclusions The model has potential to be used as a benchmarking tool for evaluating statistical and process models and may provide a mechanism to separate signal from noise and improve our ability to analyze and learn from large regional datasets that often have underlying flaws in sample design.

  7. The 7Be profiles in the undisturbed soil used for reference site to estimate the soil erosion

    Science.gov (United States)

    Raksawong, S.; Krmar, M.; Bhongsuwan, T.

    2017-06-01

    The cosmogenic radionuclide 7Be is increasingly used to obtain information on event-related soil erosion rates within agricultural landscapes. In this study, we select two undisturbed and flat areas to calculate the reference inventory and relaxation mass depth by using 7Be technique to document short-term erosion. Our results showed that the depth distribution of 7Be in undisturbed soil profiles was 1.0 cm in sites S02 and S03; the initial activities were 31.6 and 38.8 Bq.kg-1, respectively. The relaxation mass depths were 5.4 and 7.2 kg.m-2 and the measured reference 7Be inventories were 71 and 110 Bq.m-2 for sites S02 and S03, respectively. The difference values of the relaxation mass depth and the reference inventory of both sites implied that for determining a short term soil erosion using 7Be, the reference site was suggested to be selected as close as possible to the study site.

  8. Proteomic Analyses Provide Novel Insights into Plant Growth and Ginsenoside Biosynthesis in Forest Cultivated Panax ginseng (F. Ginseng)

    OpenAIRE

    Ma, Rui; Sun, Liwei; Chen, Xuenan; Mei, Bing; Chang, Guijuan; Wang, Manying; Zhao, Daqing

    2016-01-01

    F. Ginseng (Panax ginseng) is planted in the forest to enhance the natural ginseng resources, which have an immense medicinal and economic value. The morphology of the cultivated plants becomes similar to that of wild growing ginseng (W. Ginseng) over the years. So far, there have been no studies highlighting the physiological or functional changes in F. Ginseng and its wild counterparts. In the present study, we used proteomic technologies (2DE and iTRAQ) coupled to mass spectrometry to comp...

  9. The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname.

    Science.gov (United States)

    Köhl, Michael; Neupane, Prem R; Lotfiomran, Neda

    2017-01-01

    The world's forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea), Hymenaea courbaril L. (Fabacea) and Goupia glabra Aubl. (Goupiacea). The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growth-periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata) and 50 percent (G. glabra) of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time.

  10. The impact of tree age on biomass growth and carbon accumulation capacity: A retrospective analysis using tree ring data of three tropical tree species grown in natural forests of Suriname.

    Directory of Open Access Journals (Sweden)

    Michael Köhl

    Full Text Available The world's forests play a pivotal role in the mitigation of global climate change. By photosynthesis they remove CO2 from the atmosphere and store carbon in their biomass. While old trees are generally acknowledged for a long carbon residence time, there is no consensus on their contribution to carbon accumulation due to a lack of long-term individual tree data. Tree ring analyses, which use anatomical differences in the annual formation of wood for dating growth zones, are a retrospective approach that provides growth patterns of individual trees over their entire lifetime. We developed time series of diameter growth and related annual carbon accumulation for 61 trees of the species Cedrela odorata L. (Meliacea, Hymenaea courbaril L. (Fabacea and Goupia glabra Aubl. (Goupiacea. The trees grew in unmanaged tropical wet-forests of Suriname and reached ages from 84 to 255 years. Most of the trees show positive trends of diameter growth and carbon accumulation over time. For some trees we observed fluctuating growth-periods of lower growth alternate with periods of increased growth. In the last quarter of their lifetime trees accumulate on average between 39 percent (C. odorata and 50 percent (G. glabra of their final carbon stock. This suggests that old-growth trees in tropical forests do not only contribute to carbon stocks by long carbon resistance times, but maintain high rates of carbon accumulation at later stages of their life time.

  11. Strong Links Between Teleconnections and Ecosystem Exchange Found at a Pacific Northwest Old-Growth Forest from Flux Tower and MODIS EVI Data

    Energy Technology Data Exchange (ETDEWEB)

    Wharton, S; Chasmer, L; Falk, M; Paw U, K T

    2009-03-12

    Variability in three Pacific teleconnection patterns are examined to see if net carbon exchange at a low-elevation, old-growth forest is affected by climatic changes associated with these periodicities. Examined are the Pacific Decadal Oscillation (PDO), Pacific/North American Oscillation (PNA) and El Nino-Southern Oscillation (ENSO). We use nine years of eddy covariance CO{sub 2}, H{sub 2}O and energy fluxes measured at the Wind River AmeriFlux site, Washington, USA and eight years of tower-pixel remote sensing data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to address this question. We compute a new Composite Climate Index (CCI) based on the three Pacific Oscillations to divide the measurement period into positive- (2003 and 2005), negative- (1999 and 2000) and neutral-phase climate years (2001, 2002, 2004, 2006 and 2007). The forest transitioned from an annual net carbon sink (NEP = + 217 g C m{sup -2} year{sup -1}, 1999) to a source (NEP = - 100 g C m{sup -2} year{sup -1}, 2003) during two dominant teleconnection patterns. Net ecosystem productivity (NEP), water use efficiency (WUE) and light use efficiency (LUE) were significantly different (P < 0.01) during positive (NEP = -0.27 g C m{sup -2} day{sup -1}, WUE = 4.1 mg C/g H{sub 2}O, LUE = 0.94 g C MJ{sup -1}) and negative (NEP = +0.37 g C m{sup -2} day{sup -1}, WUE = 3.4 mg C/g H{sub 2}O, LUE = 0.83 g C MJ{sup -1}) climate phases. The CCI was linked to variability in the MODIS Enhanced Vegetation Index (EVI) but not to MODIS Fraction of absorbed Photosynthetically Active Radiation (FPAR). EVI was highest during negative climate phases (1999 and 2000) and was positively correlated with NEP and showed potential for using MODIS to estimate teleconnection-driven anomalies in ecosystem CO{sub 2} exchange in old-growth forests. This work suggests that any increase in the strength or frequency of ENSO coinciding with in-phase, low frequency Pacific oscillations (PDO and PNA) will likely increase

  12. Micro-scale modelling of energy fluxes over a small Fluxnet forest site in Denmark

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Dellwik, Ebba; Boegh, Eva

    2012-01-01

    Most forests, especially in Europe, are too small to fulfil strict fetch requirements associated with idealized flux observations in undisturbed, homogeneous flow. As a consequence of limited fetch, the flux measured above the canopy will often deviate from the source strength underlying the meas...

  13. Indicators of nitrate export from forested watersheds of the Chesapeake Bay region

    Science.gov (United States)

    Karl W. J. Williard

    1997-01-01

    Soil net nitrogen mineralization and nitrification rates were studied on nine relatively undisturbed, forested watersheds in an effort to explain the large variations in nitrate export in streamflow within the Chesapeake Bay region. The primary hypothesis tested was that nitrate export from the watersheds was positively associated with rates of net soil nitrogen...

  14. Morphological acclimation and growth of ash (Fraxinus pennsylvanica Marsh.) advance regeneration following overstory harvesting in a Mississippi River floodplain forest

    Science.gov (United States)

    Alexander Sinz; Emmile S. Gardiner; Brian R. Lockhart; Ray A. Souter

    2011-01-01

    Stand-level growth responses and plant-level patterns of biomass accumulation and distribution were examined to learn how stand structure influences morphological acclimation and growth of green ash (Fraxinus pennsylvanica Marsh.) advance regeneration following overstory harvesting. Nine, 20-ha plots that received clearcut harvesting (100% basal area removal), partial...

  15. Estimating root collar diameter growth for multi-stem western woodland tree species on remeasured forest inventory and analysis plots

    Science.gov (United States)

    Michael T. Thompson; Maggie. Toone

    2012-01-01

    Tree diameter growth models are widely used in many forestry applications, often to predict tree size at a future point in time. Also, there are instances where projections of past diameters are needed. An individual tree model has been developed to estimate diameter growth of multi-stem woodland tree species where the diameter is measured at root collar. The model was...

  16. The relative importance of above- versus belowground competition for tree growth during early succession of a tropical moist forest

    DEFF Research Database (Denmark)

    Breugel, Michiel van; van Breugel, Paulo; Jansen, Patrick A.

    2012-01-01

    fertility in Southern Mexico, using the premise that competition for light is size-asymmetric, unlike competition for nutrients. Plant growth is thus expected to be disproportionally impeded by larger neighbors. We studied how growth and survival of 3.5-5.5 m tall saplings of Cecropia peltata...

  17. Disparate effects of global-change drivers on mountain conifer forests: warming-induced growth enhancement in young trees vs. CO2 fertilization in old trees from wet sites.

    Science.gov (United States)

    Camarero, J Julio; Gazol, Antonio; Galván, Juan Diego; Sangüesa-Barreda, Gabriel; Gutiérrez, Emilia

    2015-02-01

    Theory predicts that the postindustrial rise in the concentration of CO2 in the atmosphere (c(a)) should enhance tree growth either through a direct fertilization effect or indirectly by improving water use efficiency in dry areas. However, this hypothesis has received little support in cold-limited and subalpine forests where positive growth responses to either rising ca or warmer temperatures are still under debate. In this study, we address this issue by analyzing an extensive dendrochronological network of high-elevation Pinus uncinata forests in Spain (28 sites, 544 trees) encompassing the whole biogeographical extent of the species. We determine if the basal area increment (BAI) trends are linked to climate warming and increased c(a) by focusing on region- and age-dependent responses. The largest improvement in BAI over the past six centuries occurred during the last 150 years affecting young trees and being driven by recent warming. Indeed, most studied regions and age classes presented BAI patterns mainly controlled by temperature trends, while growing-season precipitation was only relevant in the driest sites. Growth enhancement was linked to rising ca in mature (151-300 year-old trees) and old-mature trees (301-450 year-old trees) from the wettest sites only. This finding implies that any potential fertilization effect of elevated c(a) on forest growth is contingent on tree features that vary with ontogeny and it depends on site conditions (for instance water availability). Furthermore, we found widespread growth decline in drought-prone sites probably indicating that the rise in ca did not compensate for the reduction in water availability. Thus, warming-triggered drought stress may become a more important direct driver of growth than rising ca in similar subalpine forests. We argue that broad approaches in biogeographical and temporal terms are required to adequately evaluate any effect of rising c(a) on forest growth. © 2014 John Wiley & Sons Ltd.

  18. Late-successional forests and northern spotted owls: how effective is the Northwest Forest Plan?

    Science.gov (United States)

    Miles Hemstrom; Martin G. Raphael

    2000-01-01

    This paper describes the late-successional and old-growth forest and the northern spotted owl effectiveness monitoring plans for the Northwest Forest Plan. The effectiveness monitoring plan for late-successional and old-growth forests will track changes in forest spatial distribution, and within-stand structure and composition, and it will predict future trends.

  19. Effects of temperature, pH and carbon and nitrogen sources on growth of in vitro cultures of ectomycorrhizal isolates from Pinus heldreichii forest

    Energy Technology Data Exchange (ETDEWEB)

    Lazarević, J.; Stojičić, D.; Keča, N.

    2016-07-01

    Aim of study: This study aims to provide basic information about physiological characteristics of isolates of Lactarius deliciosus (L.) Gray, Russula sanguinaria (Schumach.) Rauschert, Suillus collinitus (Fr) Kuntze, Suillus granulatus (L.) Rousell, Tricholoma batchii Gulden and Tricholoma imbricatum (Fr.) Kumm. Area of study: The isolates are obtained from Pinus heldreichii H. Christ forest in the south-eastern part of Montenegro. Material and methods: The isolates were molecularly characterised by internal transcribed spacer (ITS) sequencing and restriction fragment length polymorphism (RFLP) analysis. The effects of different temperatures (20, 22, 25°C), pHs (4, 4.5, 5.2, 5.8, 6.5, 7.5), and carbon (glucose, sucrose, dextrin, arabinose, xylose and starch) and nitrogen (NH4+, NO3- and protein) sources on their growth were examined under laboratory conditions. Main results: The studied factors established significant differences in the development of isolates. Isolates of R. sanguinaria, L. deliciosus and both Suillus, were characterised by faster growth at 22°C, while Tricholoma isolates grew faster at 25°C. S. granulatus, S. collinitus and T. imbticatum isolates grew well at lower pH values (4 - 5.2), while L. deliciosus, R. sanguinaria and T. bachii exhibited faster growth at pHs between 5.8 and 6.5. The examined isolates were able to utilize various carbohydrates as carbon sources. The biggest mycelial growth was characterised for sucrose, then glucose, dextrin, arabinose, starch and xylose. They grew on all examined nitrogen sources, while the biggest mycelia growth was achieved on ammonium, followed by nitrate and protein. Those characteristics varied amongst the species. Research highlights: Information about physiological characteristics of Tricholoma, Lactarius, Russula, as well as Suillus, are sparse. Hence, the data obtained in this study could contribute to the understanding of their function in ecosystems. (Author)

  20. Effects of temperature, pH and carbon and nitrogen sources on growth of in vitro cultures of ectomycorrhizal isolates from Pinus heldreichii forest

    Directory of Open Access Journals (Sweden)

    Jelena Lazarević

    2016-04-01

    Full Text Available Aim of study: This study aims to provide basic information about physiological characteristics of isolates of Lactarius deliciosus (L. Gray, Russula sanguinaria (Schumach. Rauschert, Suillus collinitus (Fr Kuntze, Suillus granulatus (L. Rousell, Tricholoma batchii Gulden and Tricholoma imbricatum (Fr. Kumm.Area of study: The isolates are obtained from Pinus heldreichii H. Christ forest in the south-eastern part of Montenegro.Material and methods: The isolates were molecularly characterised by internal transcribed spacer (ITS sequencing and restriction fragment length polymorphism (RFLP analysis. The effects of different temperatures (20, 22, 25°C, pHs (4, 4.5, 5.2, 5.8, 6.5, 7.5, and carbon (glucose, sucrose, dextrin, arabinose, xylose and starch and nitrogen (NH4+, NO3- and protein sources on their growth were examined under laboratory conditions.Main results: The studied factors established significant differences in the development of isolates. Isolates of R. sanguinaria, L. deliciosus and both Suillus, were characterised by faster growth at 22°C, while Tricholoma isolates grew faster at 25°C. S. granulatus, S. collinitus and T. imbticatum isolates grew well at lower pH values (4 - 5.2, while L. deliciosus, R. sanguinaria and T. bachii exhibited faster growth at pHs between 5.8 and 6.5. The examined isolates were able to utilize various carbohydrates as carbon sources. The biggest mycelial growth was characterised for sucrose, then glucose, dextrin, arabinose, starch and xylose. They grew on all examined nitrogen sources, while the biggest mycelia growth was achieved on ammonium, followed by nitrate and protein. Those characteristics varied amongst the species.Research highlights: Information about physiological characteristics of Tricholoma, Lactarius, Russula, as well as Suillus, are sparse. Hence, the data obtained in this study could contribute to the understanding of their function in ecosystems.