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Sample records for european forest trees

  1. Tree species richness affecting fine root biomass in European forests

    Science.gov (United States)

    Finér, Leena; Domisch, Timo; Vesterdal, Lars; Dawud, Seid M.; Raulund-Rasmussen, Karsten

    2016-04-01

    Fine roots are an important factor in the forest carbon cycle, contributing significantly to below-ground biomass and soil carbon storage. Therefore it is essential to understand the role of the forest structure, indicated by tree species diversity in controlling below-ground biomass and managing the carbon pools of forest soils. We studied how tree species richness would affect fine root biomass and its distribution in the soil profile and biomass above- and below-ground allocation patterns of different tree species. Our main hypothesis was that increasing tree species richness would lead to below-ground niche differentiation and more efficient soil exploitation by the roots, resulting in a higher fine root biomass in the soil. We sampled fine roots of trees and understorey vegetation in six European forest types in Finland, Poland, Germany, Romania, Italy and Spain, representing boreal, temperate and Mediterranean forests, established within the FunDivEUROPE project for studying the effects of tree species diversity on forest functioning. After determining fine root biomasses, we identified the percentages of different tree species in the fine root samples using the near infrared reflectance spectroscopy (NIRS) method. Opposite to our hypothesis we did not find any general positive relationship between tree species richness and fine root biomass. A weak positive response found in Italy and Spain seemed to be related to dry environmental conditions during Mediterranean summers. At the Polish site where we could sample deeper soil layers (down to 40 cm), we found more tree fine roots in the deeper layers under species-rich forests, as compared to the monocultures, indicating the ability of trees to explore more resources and to increase soil carbon stocks. Tree species richness did not affect biomass allocation patterns between above- and below-ground parts of the trees.

  2. Carbon and nitrogen in forest floor and mineral soil under six common European tree species

    DEFF Research Database (Denmark)

    Vesterdal, Lars; Schmidt, Inger K.; Callesen, Ingeborg

    2007-01-01

    The knowledge of tree species effects on soil C and N pools is scarce, particularly for European deciduous tree species. We studied forest floor and mineral soil carbon and nitrogen under six common European tree species in a common garden design replicated at six sites in Denmark. Three decades...

  3. How much does climate change threaten European forest tree species distributions?

    Science.gov (United States)

    Dyderski, Marcin K; Paź, Sonia; Frelich, Lee E; Jagodziński, Andrzej M

    2018-03-01

    Although numerous species distribution models have been developed, most were based on insufficient distribution data or used older climate change scenarios. We aimed to quantify changes in projected ranges and threat level by the years 2061-2080, for 12 European forest tree species under three climate change scenarios. We combined tree distribution data from the Global Biodiversity Information Facility, EUFORGEN, and forest inventories, and we developed species distribution models using MaxEnt and 19 bioclimatic variables. Models were developed for three climate change scenarios-optimistic (RCP2.6), moderate (RCP4.5), and pessimistic (RPC8.5)-using three General Circulation Models, for the period 2061-2080. Our study revealed different responses of tree species to projected climate change. The species may be divided into three groups: "winners"-mostly late-successional species: Abies alba, Fagus sylvatica, Fraxinus excelsior, Quercus robur, and Quercus petraea; "losers"-mostly pioneer species: Betula pendula, Larix decidua, Picea abies, and Pinus sylvestris; and alien species-Pseudotsuga menziesii, Quercus rubra, and Robinia pseudoacacia, which may be also considered as "winners." Assuming limited migration, most of the species studied would face a significant decrease in suitable habitat area. The threat level was highest for species that currently have the northernmost distribution centers. Ecological consequences of the projected range contractions would be serious for both forest management and nature conservation. © 2017 John Wiley & Sons Ltd.

  4. Taxonomic and ecological relevance of the chlorophyll a fluorescence signature of tree species in mixed European forests.

    Science.gov (United States)

    Pollastrini, Martina; Holland, Vera; Brüggemann, Wolfgang; Bruelheide, Helge; Dănilă, Iulian; Jaroszewicz, Bogdan; Valladares, Fernando; Bussotti, Filippo

    2016-10-01

    The variability of chlorophyll a fluorescence (ChlF) parameters of forest tree species was investigated in 209 stands belonging to six European forests, from Mediterranean to boreal regions. The modifying role of environmental factors, forest structure and tree diversity (species richness and composition) on ChlF signature was analysed. At the European level, conifers showed higher potential performance than broadleaf species. Forests in central Europe performed better than those in Mediterranean and boreal regions. At the site level, homogeneous clusters of tree species were identified by means of a principal component analysis (PCA) of ChlF parameters. The discrimination of the clusters of species was influenced by their taxonomic position and ecological characteristics. The species richness influenced the tree ChlF properties in different ways depending on tree species and site. Tree species and site also affected the relationships between ChlF parameters and other plant functional traits (specific leaf area, leaf nitrogen content, light-saturated photosynthesis, wood density, leaf carbon isotope composition). The assessment of the photosynthetic properties of tree species, by means of ChlF parameters, in relation to their functional traits, is a relevant issue for studies in forest ecology. The connections of data from field surveys with remotely assessed parameters must be carefully explored. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  5. Converging Climate Sensitivities of European Forests Between Observed Radial Tree Growth and Vegetation Models

    Science.gov (United States)

    Zhang, Zhen; Babst, Flurin; Bellassen, Valentin; Frank, David; Launois, Thomas; Tan, Kun; Ciais, Philippe; Poulter, Benjamin

    2017-01-01

    The impacts of climate variability and trends on European forests are unevenly distributed across different bioclimatic zones and species. Extreme climate events are also becoming more frequent and it is unknown how they will affect feed backs of CO2 between forest ecosystems and the atmosphere. An improved understanding of species differences at the regional scale of the response of forest productivity to climate variation and extremes is thus important for forecasting forest dynamics. In this study, we evaluate the climate sensitivity of above ground net primary production (NPP) simulated by two dynamic global vegetation models (DGVM; ORCHIDEE and LPJ-wsl) against tree ring width (TRW) observations from about1000 sites distributed across Europe. In both the model simulations and the TRW observations, forests in northern Europe and the Alps respond positively to warmer spring and summer temperature, and their overall temperature sensitivity is larger than that of the soil-moisture-limited forests in central Europe and Mediterranean regions. Compared with TRW observations, simulated NPP from ORCHIDEE and LPJ-wsl appear to be overly sensitive to climatic factors. Our results indicate that the models lack biological processes that control time lags, such as carbohydrate storage and remobilization, that delay the effects of radial growth dynamics to climate. Our study highlights the need for re-evaluating the physiological controls on the climate sensitivity of NPP simulated by DGVMs. In particular, DGVMs could be further enhanced by a more detailed representation of carbon reserves and allocation that control year-to year variation in plant growth.

  6. Climate- and successional-related changes in functional composition of European forests are strongly driven by tree mortality.

    Science.gov (United States)

    Ruiz-Benito, Paloma; Ratcliffe, Sophia; Zavala, Miguel A; Martínez-Vilalta, Jordi; Vilà-Cabrera, Albert; Lloret, Francisco; Madrigal-González, Jaime; Wirth, Christian; Greenwood, Sarah; Kändler, Gerald; Lehtonen, Aleksi; Kattge, Jens; Dahlgren, Jonas; Jump, Alistair S

    2017-10-01

    Intense droughts combined with increased temperatures are one of the major threats to forest persistence in the 21st century. Despite the direct impact of climate change on forest growth and shifts in species abundance, the effect of altered demography on changes in the composition of functional traits is not well known. We sought to (1) quantify the recent changes in functional composition of European forests; (2) identify the relative importance of climate change, mean climate and forest development for changes in functional composition; and (3) analyse the roles of tree mortality and growth underlying any functional changes in different forest types. We quantified changes in functional composition from the 1980s to the 2000s across Europe by two dimensions of functional trait variation: the first dimension was mainly related to changes in leaf mass per area and wood density (partially related to the trait differences between angiosperms and gymnosperms), and the second dimension was related to changes in maximum tree height. Our results indicate that climate change and mean climatic effects strongly interacted with forest development and it was not possible to completely disentangle their effects. Where recent climate change was not too extreme, the patterns of functional change generally followed the expected patterns under secondary succession (e.g. towards late-successional short-statured hardwoods in Mediterranean forests and taller gymnosperms in boreal forests) and latitudinal gradients (e.g. larger proportion of gymnosperm-like strategies at low water availability in forests formerly dominated by broad-leaved deciduous species). Recent climate change generally favoured the dominance of angiosperm-like related traits under increased temperature and intense droughts. Our results show functional composition changes over relatively short time scales in European forests. These changes are largely determined by tree mortality, which should be further

  7. Tree species functional group is a more important driver of soil properties than tree species diversity across major European forest types

    Science.gov (United States)

    Vesterdal, Lars; Muhie Dawud, Seid; Raulund-Rasmussen, Karsten; Finér, Leena; Domisch, Timo; Ratcliffe, Sophia

    2017-04-01

    The influence of tree species diversity and functional group on soil properties (carbon stock, pH and C/N ratio) has not been explored across major European forest types. We evaluated the relative importance of tree species diversity and functional group on soil carbon (C) stocks, C/N ratio and pH in major European forest types in the six regions Finland, Poland, Germany, Romania, Italy and Spain. We sampled soils in 209 permanent plots along a species diversity gradient from monocultures to 5-species mixtures in the exploratory platform of the FunDivEurope project. Carbon stocks in the topsoil (forest floor (FF), 0-10 cm, and FF+0-10 cm) were positively, but weakly, related to diversity across the regions. While the C/N ratio in the FF+0-10 cm layer decreased significantly with increasing diversity in the Spanish region, pH was unrelated to species diversity across the regions. Tree species functional group (conifer proportion) explained a larger proportion of the variability in soil properties than species diversity. Conifer admixture increased C stock and C/N ratio, and decreased pH, but the impacts differed between the regions for some soil layers. Differences in mean annual temperature, actual evapotranspiration and soil texture between the regions were possible driving factors behind the different functional group effects in Finland, Spain and Germany. The results suggest that targeted selection of tree species with desired characteristics, e.g. complementary traits for resource use, is a preferred management approach for influencing soil C stock, C/N ratio and pH in mixed forests rather than increasing tree species diversity per se.

  8. Functional significance of tree species diversity and species identity on soil organic carbon, C/N ratio and pH in major European forest types

    DEFF Research Database (Denmark)

    Dawud, Seid Muhie

    Forests provide different ecosystem functions and services including soil carbon sequestration and nutrient supply to maintain growth and productivity. This PhD thesis explored tree species diversity and tree species identity (conifer proportion of basal area) effects on soil C stock and nutrient...... supply (C/N ratio and pH). The studies were carried out in (1) forest floor and mineral soil to 20 cm depth across six different sites of major European forest types based on samples from one to five tree species mixtures along a latitudinal gradient from Spain to Finland, (2) soil profiles down to 40 cm...... within comparable environmental conditions in a Polish forest area, and (3) a trans-boundary approach in adjacent monoculture stands of Douglas-fir and beech at two common garden sites in Denmark. The thesis also included tree species diversity effects on fine root biomass, production and turnover under...

  9. Transgenic Forest Trees

    Directory of Open Access Journals (Sweden)

    Ertuğrul Filiz

    2011-11-01

    Full Text Available Biotechnological methods are used in many areas nowadays and one of these areas is applications of biotechnology in forest trees. Biotechnological methods are used frequently on vital issues such as gaining resistance against diseases and herbicide of forest trees, increasing tree growth rates and development of resistance against environmental stresses (drought, salinity, climate change etc.. Also, for improving the quality of wood that reducing lignin content and increasing the amount of cellulose draws attention. This together with applications, positive and negative effects of transgenic trees to the environment is discussed and it was tried to be provided on the auditing legal regulations concerned with these studies.

  10. Trees for future forests

    DEFF Research Database (Denmark)

    Lobo, Albin

    Climate change creates new challenges in forest management. The increase in temperature may in the long run be beneficial for the forests in the northern latitudes, but the high rate at which climate change is predicted to proceed will make adaptation difficult because trees are long living sessi...

  11. Potential Population Genetic Consequences of Habitat Fragmentation in Central European Forest Trees and Associated Understorey Species—An Introductory Survey

    Directory of Open Access Journals (Sweden)

    Christoph Dobeš

    2017-02-01

    Full Text Available Habitat fragmentation threatens the maintenance of genetic diversity of affected populations. Assessment of the risks associated with habitat fragmentation is a big challenge as the change in population genetic diversity is a dynamic process, often acting over long time periods and depending on various characteristics pertaining to both species (life history traits and their populations (extrinsic characteristics. With this survey, we provide an introductory overview for persons who have to make or are interested in making predictions about the fate of forest-dwelling plant populations which have recently become fragmented and isolated from their main occurrences. We provide a concise introduction to the field of population genetics focusing on terms, processes and phenomena relevant to the maintenance of genetic diversity and vitality of plant populations. In particular the antagonistic effects of gene flow and random genetic drift are covered. A special chapter is devoted to Central European tree species (including the Carpathians which we treat in detail with reference to an extensive literature survey on population genetic studies assembled from the whole of Europe. We further provide an overview of the population biology of associated understorey species. We conclude with recommended steps to be taken for the evaluation of potential perils of habitat fragmentation or population thinning for the genetics of tree populations. The complexity of effects exerted by life history traits and extrinsic characteristics of populations suggest population genetic development is strongly situation dependent. Therefore, we recommend following a case-by-case approach ideally supported by computer simulations to predict future population genetic development of both trees and associated understorey species.

  12. Tree species is the major factor explaining C:N ratios in European forest soils

    DEFF Research Database (Denmark)

    Cools, Nathalie; Vesterdal, Lars; De Vos, Bruno

    2014-01-01

    .) and eucalyptus, the pine species and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) showed the highest C:N ratios in the mineral soil. The second most important explanatory variable in the forest floor and mineral topsoil was the biogeographical zoning (ecoregion). In the peat topsoil and in the deeper...

  13. European mixed forests

    DEFF Research Database (Denmark)

    Bravo-Oviedo, Andres; Pretzsch, Hans; Ammer, Christian

    2014-01-01

    Aim of study: We aim at (i) developing a reference definition of mixed forests in order to harmonize comparative research in mixed forests and (ii) review the research perspectives in mixed forests. Area of study: The definition is developed in Europe but can be tested worldwide. Material...... and Methods: Review of existent definitions of mixed forests based and literature review encompassing dynamics, management and economic valuation of mixed forests. Main results: A mixed forest is defined as a forest unit, excluding linear formations, where at least two tree species coexist at any...... developmental stage, sharing common resources (light, water, and/or soil nutrients). The presence of each of the component species is normally quantified as a proportion of the number of stems or of basal area, although volume, biomass or canopy cover as well as proportions by occupied stand area may be used...

  14. VEGETATION DYNAMICS IN EUROPEAN BEECH FORESTS

    Directory of Open Access Journals (Sweden)

    A. FISCHER

    1997-01-01

    Full Text Available Dynamic processes can be classified in terms of their time scale, their spatial scale, the elements observed, and the degree of human impact. Using these categories the regeneration of the tree layer, the regeneration of the herb layer as well as successional changes of supraregional importance (immissions, global change are discussed. A virgin (mixed European beech forest consists of a mosaic of sub-stands that can be typified by their structure and developmental stage (phase of the tree layer; in some phases the tree individuals of each sub-stand are rather even-aged. Natural cyclic regeneration of virgin (mixed European beech forests mainly includes the tree species of the terminal phases, expecially the beech itself. Changes of tree species composition within the cycle are the exception; in European beech forests light-demanding pioneers seem to be restricted to rather small patches under natural conditions. In contrast, the sequence (1 felled-area flora, (2 pioneer shrub/pioneer forest and (3 terminal forest is a characteristic feature of managed deciduous forests as a consequence of soil disturbances. During the cyclic regeneration of the tree layer of European beech forests the floristic content of the ground layer vegetation does not change fundamentally. Regeneration of many of the ground layer species of beech forests via generative diaspores is more or less restricted to micro-disturbances. In contrast disturbance of the topsoil and creation of open habitats for the establishment of saplings in the absence of competition is taking place all over a clear-cutting area. European beech forests are subject to changes of floristic structure caused by immissions. Especially nitrogen, emitted over decades in large quantities, causes a successive change in floristics: species requiring high amounts of nitrogen are increasing in beech forests all over Europe. Most of them are rapidly and tall growing species, outcompeting the slower and smaller

  15. A recursive algorithm for trees and forests

    OpenAIRE

    Guo, Song; Guo, Victor J. W.

    2017-01-01

    Trees or rooted trees have been generously studied in the literature. A forest is a set of trees or rooted trees. Here we give recurrence relations between the number of some kind of rooted forest with $k$ roots and that with $k+1$ roots on $\\{1,2,\\ldots,n\\}$. Classical formulas for counting various trees such as rooted trees, bipartite trees, tripartite trees, plane trees, $k$-ary plane trees, $k$-edge colored trees follow immediately from our recursive relations.

  16. Assessing the risk caused by ground level ozone to European forest trees: A case study in pine, beech and oak across different climate regions

    Energy Technology Data Exchange (ETDEWEB)

    Emberson, Lisa D. [Stockholm Environment Institute, University of York, York YO10 5DD (United Kingdom)]. E-mail: l.emberson@york.ac.uk; Bueker, Patrick [Stockholm Environment Institute, University of York, York YO10 5DD (United Kingdom); Ashmore, Mike R. [Stockholm Environment Institute, University of York, York YO10 5DD (United Kingdom)

    2007-06-15

    Two different indices have been proposed for estimation of the risk caused to forest trees across Europe by ground-level ozone, (i) the concentration based AOT40 index (Accumulated Over a Threshold of 40 ppb) and (ii) the recently developed flux based AFstY index (Accumulated stomatal Flux above a flux threshold Y). This paper compares the AOT40 and AFstY indices for three forest trees species at different locations in Europe. The AFstY index is estimated using the DO{sub 3}SE (Deposition of Ozone and Stomatal Exchange) model parameterized for Scots pine (Pinus sylvestris), beech (Fagus sylvatica) and holm oak (Quercus ilex). The results show a large difference in the perceived O{sub 3} risk when using AOT40 and AFstY indices both between species and regions. The AOT40 index shows a strong north-south gradient across Europe, whereas there is little difference between regions in the modelled values of AFstY. There are significant differences in modelled AFstY between species, which are predominantly determined by differences in the timing and length of the growing season, the periods during which soil moisture deficit limits stomatal conductance, and adaptation to soil moisture stress. This emphasizes the importance of defining species-specific flux response variables to obtain a more accurate quantification of O{sub 3} risk. - A new flux-based model provides a revised assessment of risks of ozone impacts to European forests.

  17. Role of six European tree species and land-use legacy for nitrogen and water budgets in forests

    DEFF Research Database (Denmark)

    Riis Christiansen, Jesper; Vesterdal, Lars; Callesen, Ingeborg

    2010-01-01

    Water and nutrient fluxes for single stands of different tree species have been reported in numerous studies, but comparative studies of nutrient and hydrological budgets of common European deciduous tree species are rare. Annual fluxes of water and inorganic nitrogen (N) were established in a 30...... in Denmark, Mattrup and Vallø during 2 years. Mean annual percolation below the root zone (mm yr−1±SE, n=4) ranked in the following order: maple (351±38)>lime (284±32), oak (271±25), beech (257±30), ash (307±69)≫ spruce (75±24). There were few significant tree species effects on N fluxes. However, the annual...... mean N throughfall flux (kg N ha−1 yr−1±SE, n=4) for spruce (28±2) was significantly larger than for maple (12±1), beech (11±1) and oak (9±1) stands but not different from that of lime (15±3). Ash had a low mean annual inorganic N throughfall deposition of 9.1 kg ha−1, but was only present at Mattrup...

  18. Trees of Our National Forests.

    Science.gov (United States)

    Forest Service (USDA), Washington, DC.

    Presented is a description of the creation of the National Forests system, how trees grow, managing the National Forests, types of management systems, and managing for multiple use, including wildlife, water, recreation and other uses. Included are: (1) photographs; (2) line drawings of typical leaves, cones, flowers, and seeds; and (3)…

  19. Forest, trees and agroforestry

    DEFF Research Database (Denmark)

    Rahman, Syed Ajijur; Foli, Samson; Al Pavel, Muha Abdullah

    2015-01-01

    Scientific community is concerned to address contemporary issues of food production and conserve tropical forests that support the livelihoods of millions of people. A review of the literature on deforestation, forest utilization, and landscape management for ecosystem services was conducted...... to investigate the effect on peoples’ livelihoods and the sustainability of forests in Bangladesh as a case. Results reveal that the current rate of deforestation is at 0.3% per annum meaning that, with current trends, in two decades little or no forest cover will exist in Bangladesh making the livelihoods...... of millions of people who depend on forest resources extremely vulnerable. We ask; can better implementation of forest policies and landscape management contribute to curb the current level of deforestation? Agroforestry systems in particular are a promising strategy to sustainably deliver food, nutritional...

  20. Carbon accumulation in European forests

    NARCIS (Netherlands)

    Ciais, P.; Schelhaas, M.J.; Zaehle, S.; Piao, S.L.; Cescatti, A.; Liski, J.; Luyssaert, S.; Le-Maire, G.; Schulze, E.D.; Bouriaud, O.; Freibauer, A.; Valentini, R.; Nabuurs, G.J.

    2008-01-01

    European forests are intensively exploited for wood products, yet they also form a sink for carbon. European forest inventories, available for the past 50 years, can be combined with timber harvest statistics to assess changes in this carbon sink. Analysis of these data sets between 1950 and 2000

  1. Functional significance of tree species diversity and species identity on soil organic carbon, C/N ratio and pH in major European forest types

    DEFF Research Database (Denmark)

    Dawud, Seid Muhie

    supply (C/N ratio and pH). The studies were carried out in (1) forest floor and mineral soil to 20 cm depth across six different sites of major European forest types based on samples from one to five tree species mixtures along a latitudinal gradient from Spain to Finland, (2) soil profiles down to 40 cm...... in Poland, diversity led to higher topsoil pH. However, there was a negative effect on N status as indicated by the higher C/N ratios in the deeper soil layers (20-40 cm). Further investigations are needed to unravel whether the increasing effect on soil C/N ratio results from more N-poor organic matter...... inputs or a more efficient uptake of N from the organic matter in diverse stands. Diversity positively influenced C stock particularly in mineral soils as concurrently observed across the six different sites, under the comparable environmental conditions and in two species mixtures as represented...

  2. Trees, forests and water

    NARCIS (Netherlands)

    Ellison, David; Morris, Cindy E.; Locatelli, Bruno; Sheil, Douglas; Cohen, Jane; Murdiyarso, Daniel; Gutierrez, Victoria; Noordwijk, van Meine; Creed, Irena F.; Pokorny, Jan; Gaveau, David; Spracklen, Dominick V.; Tobella, Aida Bargués; Ilstedt, Ulrik; Teuling, Adriaan J.; Gebrehiwot, Solomon Gebreyohannis; Sands, David C.; Muys, Bart; Verbist, Bruno; Springgay, Elaine; Sugandi, Yulia; Sullivan, Caroline A.

    2017-01-01

    Forest-driven water and energy cycles are poorly integrated into regional, national, continental and global decision-making on climate change adaptation, mitigation, land use and water management. This constrains humanity's ability to protect our planet's climate and life-sustaining functions. The

  3. Impacts of natural disturbances on the development of European forest resources: application of model approaches from tree and stand levels to large-scale scenarios

    NARCIS (Netherlands)

    Schelhaas, M.J.

    2008-01-01

    Natural disturbances can significantly affect the sustainable production of forest services. Until now there has been no concise overview of the damage such disturbances have caused to European forests, and their role in projection models has often been ignored. This dissertation aims to contribute

  4. 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

  5. The impact of nitrogen deposition on carbon sequestration in European forests and forest soils

    DEFF Research Database (Denmark)

    de Vries, Wim; Reinds, Gert Jan; Gundersen, Per

    2006-01-01

    yr(-1)) as the C sequestration in the soil (0.023 Gton yr(-1)). The European average impact of an additional N input on the net C sequestration was estimated at approximately 25 kg C kg(-1) N for both tree wood and soil. The contribution of an average additional N deposition on European forests of 2...... in Central Europe and low in Northern and Southern Europe. The result of this study implies that the impact of forest management on tree growth is most important in explaining the C pool changes in European forests.......An estimate of net carbon (C) pool changes and long-term C sequestration in trees and soils was made at more than 100 intensively monitored forest plots (level II plots) and scaled up to Europe based on data for more than 6000 forested plots in a systematic 16 km x 16 km grid (level I plots). C...

  6. Ancient Forests and the Tree-Ring Reconstruction of Past Climate (Ancient Forests and Dendroclimatology)

    Energy Technology Data Exchange (ETDEWEB)

    Stahle, David (Tree-Ring Laboratory, University of Arkansas)

    2003-02-12

    The original presettlement forests of North America have been dramatically altered, but thousands of unmolested ancient forests survive on remote or noncommercial terrain, including dry-site eastern hardwoods such as chestnut oak and post oak, the pinyon-juniper woodlands of the semiarid West, oak woodlands of California and in northeast Mexico, and the boreal forests of Canada and Alaska. Long tree-ring chronologies derived from these ancient forest remnants provide irreplaceable archives of environmental variability which are crucial for evaluating present and future change. Temperature sensitive tree -ring chronologies from cold treeline environments place 20th century warming into long historical perspective, and moisture sensitive tree-ring chronologies provide analogs to the decadal moisture regimes of the 20th century. These tree-ring data suggests that the 16th century megadrought was the most severe-sustained drought to impact North America in 1500 years, and had huge environmental and social impacts at the dawn of European settlement.

  7. Effects of tree diversity and environmental factors on the soil microbial community in three soil depth in a Central European beech forest

    Science.gov (United States)

    Fornacon, C.; Jacob, M.; Guckland, A.; Meinen, C.; Gleixner, G.

    2009-04-01

    We investigated the link between aboveground and belowground diversity in forest ecosystems. Therefore, we determined the effect of tree composition on amount and composition of the soil microbial community using phospholipid fatty acid profiles in the Hainich National Park in Thuringia, a deciduous mixed forest on loess over limestone in Central Germany. On the one hand we investigated the composition of the microbial community in dependence of leave litter composition, hypothesizing that distinct leave litter compositions activated signature PLFA's. On the other hand we determined if environmental factor like clay content or nutrient status influence the microbial community in deeper soil horizons. Consequently soil was sampled from depth intervals of 0-5 cm, 5-10 cm and 10-20 cm. Plots with highest diversity of leave litter had highest total amounts of fatty acids in the upper 5 cm. Mainly PLFA 16:1?5 was activated in autumn, being a common marker for mycorrhizal fungi. In soil depth below 5 cm the environmental factors like clay and soil nutrients like phosphorus and carbon, explained most of the soil microbial variability. On pure beech sites the total phosphorus content of soil influenced soil microbial diversity, but on sites with higher tree diversity no single factor varying the microbial community could be identified. Tree diversity and environmental factors together effect soil microbial community and are closely related to the link between aboveground and belowground diversity.

  8. Tree height and tropical forest biomass estimation

    Science.gov (United States)

    M.O. Hunter; M. Keller; D. Vitoria; D.C. Morton

    2013-01-01

    Tropical forests account for approximately half of above-ground carbon stored in global vegetation. However, uncertainties in tropical forest carbon stocks remain high because it is costly and laborious to quantify standing carbon stocks. Carbon stocks of tropical forests are determined using allometric relations between tree stem diameter and height and biomass....

  9. Utilizing forest tree genetic diversity for an adaptation of forest to climate change

    Science.gov (United States)

    Schueler, Silvio; Lackner, Magdalena; Chakraborty, Debojyoti

    2017-04-01

    Since climate conditions are considered to be major determinants of tree species' distribution ranges and drivers of local adaptation, anthropogenic climate change (CC) is expected to modify the distribution of tree species, tree species diversity and the forest ecosystems connected to these species. The expected speed of environmental change is significantly larger than the natural migration and adaptation capacity of trees and makes spontaneous adjustment of forest ecosystems improbable. Planting alternative tree species and utilizing the tree species' intrinsic adaptive capacity are considered to be the most promising adaptation strategy. Each year about 900 million seedlings of the major tree species are being planted in Central Europe. At present, the utilization of forest reproductive material is mainly restricted to nationally defined ecoregions (seed/provenance zones), but when seedlings planted today become adult, they might be maladapted, as the climate conditions within ecoregions changed significantly. In the cooperation project SUSTREE, we develop transnational delineation models for forest seed transfer and genetic conservation based on species distribution models and available intra-specific climate-response function. These models are being connected to national registers of forest reproductive material in order support nursery and forest managers by selecting the appropriate seedling material for future plantations. In the long-term, European and national policies as well as regional recommendations for provenances use need to adapted to consider the challenges of climate change.

  10. Spatial distribution of regional whole tree carbon stocks and fluxes of forests in Europe

    NARCIS (Netherlands)

    Schelhaas, M.J.; Nabuurs, G.J.

    2001-01-01

    This report presents carbon stocks and fluxes of the whole-tree biomass of European forests and other wooded land, distinguished into coniferous, deciduous and mixed forests. The results are presented at the European, the national and (where possible)the regional level. Results concerning carbon

  11. Belowground carbon trade among tall forest trees

    Science.gov (United States)

    Klein, Tamir; Siegwolf, Rolf; Koerner, Christian

    2016-04-01

    Just imagine one tree could hand over large quantities of carbon to another tree. How would that change our thinking about carbon relations of forests, the single biggest biological C reservoir on earth? If such a tree-to-tree C shuttle would exist, it required a demand-supply gradient and a pipeline. Here we show that exactly this unthinkable does occur in overlapping root spheres of tall trees in a mixed temperate forest. Using canopy scale stable carbon isotope labelling applied from a construction crane, we demonstrate that carbon assimilated by spruce is traded over to neighbouring beech, larch, and pine in amounts so large that fine roots almost equilibrate the carbon source signature. The isotope mixing ratio indicated that the interspecific transfer accounted for 40% of the fine root carbon, which is ca. 280 kg ha-1 a-1. This is the first forest scale evidence of a large flux of carbon among mature trees from evolutionary distant taxa. Carbon transfer most likely occurred through common ectomycorrhiza networks, which also exhibited the labelled carbon signal. These observations indicate that while competition for resources (e.g. light, water, nutrients) is often considered the dominant tree-tree interaction in a forest, trees actually interact in more complex pathways including a massive carbon exchange.

  12. Assessing the resources and mitigation potential of European forests

    Science.gov (United States)

    Hasenauer, Hubert; Neumann, Mathias; Moreno, Adam; Running, Steve

    2017-04-01

    Today 40 % of the European land area is covered with forests managed for the provision of ecosystem services including timber production. Forests store large amounts of carbon and are the main resource for the growing demand of a bio-based economy. They are also a major source for biodiversity. Thus a consistent pan-European gridded data set on the state of forest resources is essential for researchers, policy makers and conservationists to study and understand the European forests for the global carbon cycle independent of political boundaries. The purpose of this study is to use existing European data to develop a consistent pan-European data set for Net Primary Production (NPP), live tree carbon per hectare, volume per hectare, mean tree height and mean tree age by integrating remotely sensed satellite data and harmonized NFI data from 13 different European countries. We provide new NPP estimates using the MOD17 algorithm by collating a newly down-scaled daily climate dataset across Europe. By consolidating these two independent productivity data sources (top down satellite versus bottom up terrestrial forest NFI data) for assessing forest resources in Europe, we are able to detect and quantify forest management impacts. We produce a pan-European map for each of the five key variables on a 0.133° grid representing the time period 2000-2010. The results show distinct differences in the carbon storage of European forests due to biophysical limits and regional historic drivers in forest management, which directly affect the carbon mitigation option of European forests. We use this data to assess the state of forest resources across Europe showing that mountainous regions have the highest carbon and volume per hectare values, central Europe has the tallest mean tree heights and Austria and Northern Scandinavia have the oldest mean tree ages. Cross-validation of the data indicates that the error varies by forest characteristic but shows negligible biases for all. We

  13. Decision trees and forests: a probabilistic perspective

    OpenAIRE

    Lakshminarayanan, B.

    2016-01-01

    Decision trees and ensembles of decision trees are very popular in machine learning and often achieve state-of-the-art performance on black-box prediction tasks. However, popular variants such as C4.5, CART, boosted trees and random forests lack a probabilistic interpretation since they usually just specify an algorithm for training a model. We take a probabilistic approach where we cast the decision tree structures and the parameters associated with the nodes of a decision tree as a probabil...

  14. Conservation of Germplasm in Forest Trees

    Science.gov (United States)

    Constance I. Millar

    1993-01-01

    Forest trees meet human needs and contribute to natural ecosystems in unique and diverse ways. As a source of fuel and fiber, they are important commodities. As dominant members of many natural ecosystems, they play keystone ecological roles in plant and animal communities. As habitat for other organisms, forests are a reservoir of great natural diversity. In...

  15. Markers of environmental stress in forest trees

    Science.gov (United States)

    Rakesh Minocha

    1999-01-01

    Gradual long-term changes in soil and environmental factors due to human activity, may affect forest trees and lead to loss of forest productivity. In most cases, the symptoms of stress appear too late for their effects to be reversed through management and/or treatment.

  16. Tree agency and urban forest governance

    DEFF Research Database (Denmark)

    Konijnendijk, Cecil Cornelis

    2016-01-01

    Purpose – The role of urban forests and urban trees in creating vibrant and resilient cities is widely recognised. Urban forest governance as the strategic decision and rule making for urban tree resources is no longer solely the domain of governmental actors, but occurs rather often as network...... governance also involving businesses and civic society. However, governance theory usually does not consider the role of non-human agency, which can be considered problematic due to, for example, the important role of urban trees in place making. The purpose of this paper is to provide further insight...... into the importance of considering tree agency in governance. Design/methodology/approach – Taking an environmental governance and actor network theory perspective, the paper presents a critical view of current urban forest governance, extending the perspective to include not only a wide range of human actors...

  17. From natural forest to tree crops, co-domestication of forests and tree species: an overview.

    NARCIS (Netherlands)

    Wiersum, K.F.

    1997-01-01

    The process of domestication of tree crops has only been given limited attention. This process starts with the protection of natural forests and ends with the cultivation of domesticated tree crops. In this evolutionary process three types of human-influenced forest environments may be

  18. 29 CFR 780.208 - Forest and Christmas tree activities.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Forest and Christmas tree activities. 780.208 Section 780... Christmas tree activities. Operations in a forest tree nursery such as seeding new beds and growing and transplanting forest seedlings are not farming operations. The planting, tending, and cutting of Christmas trees...

  19. EUFODOS: European Forest Downstream Services – Improved Information on Forest Structure and Damage

    Directory of Open Access Journals (Sweden)

    M. Hirschmugl

    2013-05-01

    Full Text Available Forests play a key role in the European economy and environment. This role incorporates ecological functions which can be affected by the occurrence of insect infestations, forest fire, heavy snowfall or windfall events. Local or Regional Authorities (LRAs thus require detailed information on the degradation status of their forests to be able to take appropriate measures for their forest management plans. In the EUFODOS project, state-of-the-art satellite and laser scanning technologies are used to provide forest authorities with cost-effective and comprehensive information on forest structure and damage. One of the six test sites is located in the Austrian province of Styria where regional forest authorities have expressed a strong need for detailed forest parameters in protective forest. As airborne laser-scanning data is available, it will be utilized to derive detailed forest parameters such as the upper forest border line, tree height, growth classes, forest density, vertical structure or volume. At the current project status, the results of (i the forest border line, (ii the segmentation of forest stands and (iii the tree top detection are available and presented including accuracy assessment and interim results are shown for timber volume estimations. The final results show that the forest border can be mapped operationally with an overall accuracy of almost 99% from LiDAR data. For the segmentation of forest stands, a comparison of the automatically derived result with visual-manual delineation showed in general a more detailed segmentation result, but for all visual-manual segments a congruence of 87% within a 4 m buffer. Tree top detections were compared to stem numbers estimated based on angle-count samplings in a field campaign, which led to a correlation coefficient (R of 0.79.

  20. Hotspots of the European forests carbon cycle

    NARCIS (Netherlands)

    Nabuurs, G.J.; Thürig, E.; Heidema, N.; Armolaitis, K.; Biber, P.; Cieciala, E.; Kaufmann, E.; Mäkipää, R.; Nilsen, P.; Petritsch, R.; Pristova, T.; Rock, J.; Schelhaas, M.J.; Sievanen, R.; Somogyi, Z.; Vallet, P.

    2008-01-01

    This paper is the outcome of a group discussion held at the Savonlinna meeting `Management of forest ecosystems and its impact on the GHG budget¿. The aim of this break-out group discussion was to `Characterize forest management impacts on the GHG budget of forest ecosystems in different European

  1. Long-term effects of gap creation and liming on understory vegetation with a focus on tree regeneration in a European beech (Fagus sylvatica L. forest

    Directory of Open Access Journals (Sweden)

    N. Lin

    2014-12-01

    Full Text Available The long-term effects of gap creation and liming on tree regeneration and understory competition were examined in a mature European beech (Fagus sylvatica stand on a nutrient-poor site. In 1989, trees were felled to create four 30 m wide circular gaps, and 3 t ha-1 fine dolomite was applied to two of these gaps and the surrounding area, whereas the remaining two gaps and most parts of the stand remained untreated. In 2010, the stand density was 153 trees x ha-1 and the basal area was 29.51 m2 x ha-1. Testing a factorial combination of two levels of canopy cover (gap and stand and two levels of lime application (limed and unlimed, the results of the case study partly support our initial hypothesis that the combined or single effects of liming and canopy removal on understory plant communities last for more than 20 years. Some effects disappeared slowly over time, while others did not. Understory vegetation of the unlimed gaps and thelimed and unlimed stands was rapidly dominated by beech regeneration, whereas limed gaps were dominated by fireweed (Epilobium angustifolium, bramble (Rubus fruticosus agg. and raspberry (Rubus ideaus for around 14 years. There, the density of the beech regeneration was reduced by competitive ground vegetation species. Plant species richness (n/100 m² was still significantly different after 23 years, with an average 10 species per 100 m² in the limed stand area, 5 species in the unlimed stand area, 25 species in the limed gaps, and only 5 species in the unlimed gaps. Only the combination of liming and canopy removal enhanced the species richness in the long run. On our study site, this combination of liming and canopy opening had a long lasting influence on the ground vegetation in terms of retarding the beech regeneration and enhancing species’ richness.

  2. Generalized biomass and leaf area allometric equations for European tree species incorporating stand structure, tree age and climate

    OpenAIRE

    FORRESTER DAVID; TACHAUER ELOISE; ANNIGHOEFER PETER; BARBEITO IGNACIO; PRETZSCH HANS; RUIZ-PEINADO RICARDO; STARK HENDRIK; VACCHIANO GIORGIO; ZLATANOV TZVETAN; CHAKRABORTY TAMALIKA; SAHA SOMID; SILESHI GUDETA W.

    2017-01-01

    Biomass and leaf area equations are often required to assess or model forest productivity, carbon stocks and other ecosystem services. These factors are influenced by climate, age and stand structural attributes including stand density and tree species diversity or species composition. However, such covariates are rarely included in biomass and leaf area equations. We reviewed the literature and built a database of biomass and leaf area equations for 24 European tree species and 3 introduced ...

  3. The dynamics of strangling among forest trees.

    Science.gov (United States)

    Okamoto, Kenichi W

    2015-11-07

    Strangler trees germinate and grow on other trees, eventually enveloping and potentially even girdling their hosts. This allows them to mitigate fitness costs otherwise incurred by germinating and competing with other trees on the forest floor, as well as minimize risks associated with host tree-fall. If stranglers can themselves host other strangler trees, they may not even seem to need non-stranglers to persist. Yet despite their high fitness potential, strangler trees neither dominate the communities in which they occur nor is the strategy particularly common outside of figs (genus Ficus). Here we analyze how dynamic interactions between strangling and non-strangling trees can shape the adaptive landscape for strangling mutants and mutant trees that have lost the ability to strangle. We find a threshold which strangler germination rates must exceed for selection to favor the evolution of strangling, regardless of how effectively hemiepiphytic stranglers may subsequently replace their hosts. This condition describes the magnitude of the phenotypic displacement in the ability to germinate on other trees necessary for invasion by a mutant tree that could potentially strangle its host following establishment as an epiphyte. We show how the relative abilities of strangling and non-strangling trees to occupy empty sites can govern whether strangling is an evolutionarily stable strategy, and obtain the conditions for strangler coexistence with non-stranglers. We then elucidate when the evolution of strangling can disrupt stable coexistence between commensal epiphytic ancestors and their non-strangling host trees. This allows us to highlight parallels between the invasion fitness of strangler trees arising from commensalist ancestors, and cases where strangling can arise in concert with the evolution of hemiepiphytism among free-standing ancestors. Finally, we discuss how our results can inform the evolutionary ecology of antagonistic interactions more generally

  4. Pear Thrips on Forest Trees (Pest Alert)

    Science.gov (United States)

    James O' Brien; Parker Snowden

    1989-01-01

    The pear thrips, Taeniothrips inconsequens (Uzel), an imported species first noted in California in 1904 and now throughout the United States, is a common thrips found on many plants, but particularly fruit trees. Pear thrips have been considered a serious forest pest only recently (1979, when they, along with Thrips calcaratus Uzel, caused widespread defoliation in...

  5. Genetic transformation of forest trees | Diouf | African Journal of ...

    African Journals Online (AJOL)

    In this review, the recent progress on genetic transformation of forest trees were discussed. Its described also, different applications of genetic engineering for improving forest trees or understanding the mechanisms governing genes expression in woody plants. Key words: Genetic transformation, transgenic forest trees, ...

  6. Standing dead tree resources in forests of the United States

    Science.gov (United States)

    Christopher W. Woodall; Karen L. Waddell; Christopher M. Oswalt; James E. Smith

    2013-01-01

    Given the importance of standing dead trees to numerous forest ecosystem attributes/ processes such as fuel loadings and wildlife habitat, the Forest Inventory and Analysis (FIA) Program of the Forest Service, U.S. Department of Agriculture, initiated a consistent nationwide inventory of standing dead trees in 1999. As the first cycle of annual standing dead tree...

  7. Monitoring trees outside forests: a review.

    Science.gov (United States)

    Schnell, Sebastian; Kleinn, Christoph; Ståhl, Göran

    2015-09-01

    Trees outside forests (TOFs) are an important natural resource that contributes substantially to national biomass and carbon stocks and to the livelihood of people in many regions. Over the last decades, decision makers have become increasingly aware of the importance of TOF, and as a consequence, this tree resource is nowadays often considered in forest monitoring systems. Our review shows that in many cases, TOF are included in national forest inventories, applying traditional methodologies with relatively sparse networks of field sample plots. Only in some countries, such as India, the design of the inventories has considered the special features of how TOFs occur in the landscape. Several research studies utilising remote sensing for monitoring TOF have been conducted lately, but very few studies include comparative studies to optimise sampling strategies for TOF. Our review indicates that methods combining remote sensing and field surveys appear to be very promising, especially when remote sensing techniques that assess both the horizontal and vertical structures of tree resources are applied. For example, two-phase sampling strategies with laser scanning in the first phase and a field survey in the second phase appear to be effective for assessing TOF resources. However, TOFs often exhibit different characteristics than forest trees. Thus, to improve TOF monitoring, there is often a need to develop models, e.g. for biomass assessment, that are specifically adapted to this tree resource. Alternatively, field-based remote sensing methods that provide structural information about individual trees, notably terrestrial laser scanning, could be further developed for TOF monitoring applications. This also would have a potential to reduce the problem of accessing TOF during field surveys, which is a problem, for example, in countries where TOF are present on intensively utilised private grounds like gardens and agricultural fields.

  8. Dominant forest tree mycorrhizal type mediates understory plant invasions

    Science.gov (United States)

    Insu Jo; Kevin M. Potter; Grant M. Domke; Songlin Fei

    2017-01-01

    Forest mycorrhizal type mediates nutrient dynamics, which in turn can influence forest community structure and processes. Using forest inventory data, we explored how dominant forest tree myc- orrhizal type affects understory plant invasions with consideration of forest structure and soil properties. We found that arbuscular mycorrhizal (AM) dominant forests, which are...

  9. Foliar and soil concentrations and stoichiometry of nitrogen and phosphorous across European Pinus sylvestris forests : Relationships with climate, N deposition and tree growth

    NARCIS (Netherlands)

    Sardans, Jordi; Alonso, Rocio; Janssens, Ivan A.; Carnicer, Jofre; Vereseglou, Stavros; Rillig, Matthias C.; Fernández-Martínez, Marcos; Sanders, Tanja G M; Peñuelas, Josep

    2016-01-01

    This study investigated the factors underlying the variability of needle and soil elemental composition and stoichiometry and their relationships with growth in Pinus sylvestris forests throughout the species' distribution in Europe by analysing data from 2245 forest stands. Needle N concentrations

  10. Forest Management Intensity Affects Aquatic Communities in Artificial Tree Holes.

    Science.gov (United States)

    Petermann, Jana S; Rohland, Anja; Sichardt, Nora; Lade, Peggy; Guidetti, Brenda; Weisser, Wolfgang W; Gossner, Martin M

    2016-01-01

    Forest management could potentially affect organisms in all forest habitats. However, aquatic communities in water-filled tree-holes may be especially sensitive because of small population sizes, the risk of drought and potential dispersal limitation. We set up artificial tree holes in forest stands subject to different management intensities in two regions in Germany and assessed the influence of local environmental properties (tree-hole opening type, tree diameter, water volume and water temperature) as well as regional drivers (forest management intensity, tree-hole density) on tree-hole insect communities (not considering other organisms such as nematodes or rotifers), detritus content, oxygen and nutrient concentrations. In addition, we compared data from artificial tree holes with data from natural tree holes in the same area to evaluate the methodological approach of using tree-hole analogues. We found that forest management had strong effects on communities in artificial tree holes in both regions and across the season. Abundance and species richness declined, community composition shifted and detritus content declined with increasing forest management intensity. Environmental variables, such as tree-hole density and tree diameter partly explained these changes. However, dispersal limitation, indicated by effects of tree-hole density, generally showed rather weak impacts on communities. Artificial tree holes had higher water temperatures (on average 2°C higher) and oxygen concentrations (on average 25% higher) than natural tree holes. The abundance of organisms was higher but species richness was lower in artificial tree holes. Community composition differed between artificial and natural tree holes. Negative management effects were detectable in both tree-hole systems, despite their abiotic and biotic differences. Our results indicate that forest management has substantial and pervasive effects on tree-hole communities and may alter their structure and

  11. Climate change may cause severe loss in the economic value European forest land

    NARCIS (Netherlands)

    Hanewinkel, M.; Cullman, D.A.; Schelhaas, M.J.; Nabuurs, G.J.; Zimmerman, N.

    2013-01-01

    European forests, covering more than 2¿million¿km2 or 32% of the land surface1, are to a large extent intensively managed and support an important timber industry. Climate change is expected to strongly affect tree species distribution within these forests2, 3. Climate and land use are undergoing

  12. Dominant forest tree mycorrhizal type mediates understory plant invasions.

    Science.gov (United States)

    Jo, Insu; Potter, Kevin M; Domke, Grant M; Fei, Songlin

    2018-02-01

    Forest mycorrhizal type mediates nutrient dynamics, which in turn can influence forest community structure and processes. Using forest inventory data, we explored how dominant forest tree mycorrhizal type affects understory plant invasions with consideration of forest structure and soil properties. We found that arbuscular mycorrhizal (AM) dominant forests, which are characterised by thin forest floors and low soil C : N ratio, were invaded to a greater extent by non-native invasive species than ectomycorrhizal (ECM) dominant forests. Understory native species cover and richness had no strong associations with AM tree dominance. We also found no difference in the mycorrhizal type composition of understory invaders between AM and ECM dominant forests. Our results indicate that dominant forest tree mycorrhizal type is closely linked with understory invasions. The increased invader abundance in AM dominant forests can further facilitate nutrient cycling, leading to the alteration of ecosystem structure and functions. © 2017 John Wiley & Sons Ltd/CNRS.

  13. Assisting Sustainable Forest Management and Forest Policy Planning with the Sim4Tree Decision Support System

    Directory of Open Access Journals (Sweden)

    Floris Dalemans

    2015-03-01

    Full Text Available As European forest policy increasingly focuses on multiple ecosystem services and participatory decision making, forest managers and policy planners have a need for integrated, user-friendly, broad spectrum decision support systems (DSS that address risks and uncertainties, such as climate change, in a robust way and that provide credible advice in a transparent manner, enabling effective stakeholder involvement. The Sim4Tree DSS has been accordingly developed as a user-oriented, modular and multipurpose toolbox. Sim4Tree supports strategic and tactical forestry planning by providing simulations of forest development, ecosystem services potential and economic performance through time, from a regional to a stand scale, under various management and climate regimes. Sim4Tree allows comparing the performance of different scenarios with regard to diverse criteria so as to optimize management choices. This paper explains the concept, characteristics, functionalities, components and use of the current Sim4Tree DSS v2.5, which was parameterized for the region of Flanders, Belgium, but can be flexibly adapted to allow a broader use. When considering the current challenges for forestry DSS, an effort has been made towards the participatory component and towards integration, while the lack of robustness remains Sim4Tree’s weakest point. However, its structural flexibility allows many possibilities for future improvement and extension.

  14. An index of forest management intensity based on assessment of harvested tree volume, tree species composition and dead wood origin

    Directory of Open Access Journals (Sweden)

    Tiemo Kahl

    2014-04-01

    Full Text Available Forest management intensity often affects biodiversity, ecosystem processes and ecosystem services. To assess the influence of past management intensity on current ecosystem properties, management intensity must be quantified in a meaningful and reproducible approach. Here we developed the simple yet effective Forest Management Intensity index (ForMI, which is based only on inventory data of the living stand, stumps and dead wood. The ForMI is the sum of three components taking into account: 1. the proportion of harvested tree volume (Iharv, 2. the proportion of tree species that are not part of the natural forest community (Inonat and 3. the proportion of dead wood showing signs of saw cuts (Idwcut. Each component ranges between 0 (no sign of management and 1 (intensive management. Our analysis suggests that the ForMI can be used to assess management intensity in Central European forests for the last 30 to 40 years, depending on decay rates of stumps and dead wood. Our approach was tested using data of 148 forest plots of 1 ha in size in Germany. We found a significant distinction between plots that were previously described as managed and unmanaged as well as between plots comprising trees species of the natural forest community and those with additional, introduced coniferous tree species. We conclude that the index is applicable to a wide range of forest management types, but should not be misinterpreted as an index for old-growth structure.

  15. Outlook for the development of European forest resources; a study prepared for the European Forest Sector Outlook Study (EFSOS)

    NARCIS (Netherlands)

    Schelhaas, M.J.; Brusselen, van J.; Pussinen, A.; Pesonen, E.; Schuck, A.; Nabuurs, G.J.; Sasse, V.

    2006-01-01

    This Outlook for the Development of European Forest Resources provides the methodologies, data, scenarios, and results of the outlook on the European forest resources from 2000 to 2040. The aim of this forest resource study was to analyse the impacts on the European forest resources under the level

  16. Upland beech trees significantly contribute to forest methane exchange

    Science.gov (United States)

    Machacova, Katerina; Maier, Martin; Svobodova, Katerina; Halaburt, Ellen; Haddad, Sally; Lang, Friederike; Urban, Otmar

    2016-04-01

    Methane (CH4) can be emitted not only from soil, but also from plants. Fluxes of CH4were predominantly investigated in riparian herbaceous plants, whereas studies on trees, particularly those lacking an aerenchyma, are rare. In soil produced CH4 can be taken up by roots, transported via intercellular spaces and the aerenchyma system, or transpiration stream to aboveground plant tissues and released to the atmosphere via lenticels or stomata. Although CH4 might be also produced by microorganisms living in plant tissues or photochemical processes in plants, these processes are relatively minor. It has been shown that seedlings of European beech (Fagus sylvatica) emit CH4 from its stems despite the lack of an aerenchyma. Our objectives were to determine the CH4 fluxes from mature beech trees and adjacent soil under natural field conditions, and to estimate the role of trees in the CH4exchange within the soil-tree-atmosphere continuum. Measurements were conducted in two mountain beech forests with different geographical and climatic conditions (White Carpathians, Czech Republic; Black Forest, Germany). CH4 fluxes at stems (profile) and root bases level were simultaneously measured together with soil-atmosphere fluxes using static chamber systems followed by chromatographic analysis or continuous laser detection of CH4 concentrations. Our study shows that mature beech trees have the ability to exchange CH4 with the atmosphere. The beech stems emitted CH4 into the atmosphere at the White Carpathians site in the range from 2.00 to 179 μg CH4 m-2 stem area h-1, while CH4 flux rates ranged between -1.34 to 1.73 μg CH4 m-2 h-1 at the Black Forest site. The root bases of beech trees from the White Carpathians released CH4 into the atmosphere (from 0.62 to 49.8 μg CH4 m-2 root area h-1), whereas a prevailing deposition was observed in the Black Forest (from -1.21 to 0.81 μg CH4 m-2 h-1). These fluxes seem to be affected by soil water content and its spatial heterogeneity

  17. European Mixed Forests: definition and research perspectives

    Directory of Open Access Journals (Sweden)

    Andres Bravo-Oviedo

    2014-12-01

    Full Text Available Aim of study: We aim at (i developing a reference definition of mixed forests in order to harmonize comparative research in mixed forests and (ii review the research perspectives in mixed forests.Area of study: The definition is developed in Europe but can be tested worldwide.Material and Methods: Review of existent definitions of mixed forests based and literature review encompassing dynamics, management and economic valuation of mixed forests.Main results: A mixed forest is defined as a forest unit, excluding linear formations, where at least two tree species coexist at any developmental stage, sharing common resources (light, water, and/or soil nutrients. The presence of each of the component species is normally quantified as a proportion of the number of stems or of basal area, although volume, biomass or canopy cover as well as proportions by occupied stand area may be used for specific objectives. A variety of structures and patterns of mixtures can occur, and the interactions between the component species and their relative proportions may change over time.The research perspectives identified are (i species interactions and responses to hazards, (ii the concept of maximum density in mixed forests, (iii conversion of monocultures to mixed-species forest and (iv economic valuation of ecosystem services provided by mixed forests.Research highlights: The definition is considered a high-level one which encompasses previous attempts to define mixed forests. Current fields of research indicate that gradient studies, experimental design approaches, and model simulations are key topics providing new research opportunities.Keywords: COST Action; EuMIXFOR; mixed-species forests; admixtures of species.

  18. Tree mortality after synchronized forest insect outbreaks: effects of tree species, bole diameter, and cutting history

    Science.gov (United States)

    Tracey N. Johnson; Steven W. Buskirk; Gregory D. Hayward; Martin G. Raphael

    2014-01-01

    A recent series of bark beetle outbreaks in the Rocky Mountain region of the U.S. is the largest and most intense ever recorded. Factors contributing to tree mortality from bark beetles are complex, but include aspects of forest stand condition. Because stand conditions respond to forest management, evaluating bark beetle-caused tree mortality and changes in forest...

  19. Tree rings in the tropics: a study on growth and ages of Bolivian rain forest trees

    NARCIS (Netherlands)

    Brienen, Roel Jacobus Wilhelmus

    2005-01-01

    Detailed information on long-term growth rates and ages of tropical rain forest trees is important to obtain a better understanding of the functioning of tropical rain forests. Nevertheless, little is known about long-term growth or ages of tropical forest trees, due to a supposed lack of annual

  20. Science in the city: Urban trees, forests, and people

    Science.gov (United States)

    Kathleen L. Wolf

    2016-01-01

    The article, intended for professional and manager audiences, is an overview of current research in urban forestry. Topics include tree science, forest risks, forest management and assessment, ecosystem services, and urban socio-ecological systems (including governance and stewardship).

  1. Genetic improvement of forest tree species

    Directory of Open Access Journals (Sweden)

    Teotônio Francisco Assis

    2011-01-01

    Full Text Available Brazilian forestry sector is considered one of the most developed in the world, being the base for important industrialsegments which use wood as raw material. Tree breeding has played an important role on improving the competitiveness ofBrazilian forestry-based companies, especially for its positive reflexes on increasing adaptation, forestry productivity and woodquality. In spite of the importance of other forest trees for the economy, such as Schizolobium, Araucaria, Populus and Hevea, themain genera under genetic improvement in the country are Eucalyptus, Pinus, Acacia and Tectona. They are used by industries likepulp and paper, siderurgy, tannin, chips for exportation and lumber, constituting an important source of revenues for the Brazilian’seconomy, besides their positive social and environmental impacts. This paper presents a generic approach to genetic improvementaspects of these four major genera currently undergoing breeding in Brazil.

  2. A BiomeBGC-based Evaluation of Dryness Stress of Central European Forests

    OpenAIRE

    Buddenbaum, H.; Hientgen, J.; Dotzler, S.; Werner, W.; Hill, J.

    2015-01-01

    Dryness stress is expected to become a more common problem in central European forests due to the predicted regional climate change. Forest management has to adapt to climate change in time and think ahead several decades in decisions on which tree species to plant at which locations. The summer of 2003 was the most severe dryness event in recent time, but more periods like this are expected. Since forests on different sites react quite differently to drought conditions, we used the ...

  3. Analysis of forest naturalness and tree mortality patterns in Estonia

    Science.gov (United States)

    J.A. Stanturf

    2009-01-01

    New methods for evaluating structural properties of stands and individual tree mortality within forests are needed to enhance biodiversity assessment in forest inventories. One approach is to assess the degree of naturalness in a forest. We assessed forest naturalness by examining patterns and causes of mortality and deadwood amount and...

  4. The European carbon balance. Part 3: forests

    NARCIS (Netherlands)

    Luyssaert, S.; Ciais, P.; Piao, S.L.; Schulze, E.D.; Jung, M.; Zaehle, S.; Schelhaas, M.J.; Reichstein, M.; Churkina, G.; Papale, D.; Abril, G.; Beer, C.; Grace, J.; Loustau, D.; Matteucci, G.; Magnani, F.; Nabuurs, G.J.; Verbeeck, H.; Sulkava, M.; van der Werf, G.R.; Janssens, I.A.

    2010-01-01

    We present a new synthesis, based on a suite of complementary approaches, of the primary production and carbon sink in forests of the 25 member states of the European Union (EU-25) during 1990-2005. Upscaled terrestrial observations and model-based approaches agree within 25% on the mean net primary

  5. Future harvesting pressure on European forests

    NARCIS (Netherlands)

    Nabuurs, G.J.; Pussinen, A.; Brusselen, van J.; Schelhaas, M.J.

    2007-01-01

    We provide quantitative insight in the spatial distribution of the future supply of wood as a raw material from European forests (27 countries) until 2060. This supply is tested for two scenarios: `projection of historical management¿ and `new management trends¿ and compared against a benchmark

  6. PATTERNS OF PEDOTURBATION BY TREE UPROOTING IN FOREST SOILS

    Directory of Open Access Journals (Sweden)

    M.V. Bobrovsky

    2016-03-01

    Full Text Available The fall of a tree accompanied by its uprooting is the most common natural end of the tree life. To understand how soil is affected by treefalls, it is necessary to recognize their signs in soil profiles, even when their surface features (pit-and-mound topography are erased. The paper reviews these signs of treefalls in soil profiles, which can be used to distinguish the patterns of old treefall-related pedoturbations. The paper is based on a literature analysis and results of authors’ long-term studies of forest soil in the European part of Russia and in the Western Siberia. Two main types of uprooting of a falling tree (hinge and rotational treefalls are considered. The paper presents data on the sizes of 424 pit-and-mound soil complexes for nine tree species (Tilia cordata, Acer platanoides, Fraxinus excelsior, Ulmus glabra, Quercus robur, Betula pendula, Populus tremula, Picea abies and Pinus sylvestris and describes peculiarities of soil relocation in the process of different treefalls, which is necessary to recognize old treefall complexes in soil profiles. The following soil-profile signs of treefalls are considered: (1 treefall pits (cauldrons; (2 spotty or streaky structures of different degrees of contrast; (3 blocks of “buried material” from the upper soil layers; (4 washed (bleached material depositing at the bottom of pits and filling soil pores and channels of various origins; (5 signs of hydrogenous changes of soil material resulting from water stagnation in the pits; (6 root channels at the bottom of the pit and (7 inclusions of litter and charcoal. As shown by our studies, treefall-related pedoturbations affect soil profiles at a depth larger than the depth usually described by the soil horizons A, E, Bhs, etc. A conclusion is made that in most forest soils, the middle and lower parts of profiles have patterns originating from the transfer of soil material upon treefalls.

  7. Genetic transformation of forest trees | Diouf | African Journal of ...

    African Journals Online (AJOL)

    In this review, the recent progress on genetic transformation of forest trees were discussed. Its described also, different applications of genetic engineering for improving forest trees or understanding the mechanisms governing genes expression in woody plants. ... African Journal of Biotechnology Vol.2(10) 2003: 328-333 ...

  8. Urban trees and forests of the Chicago region

    Science.gov (United States)

    David J. Nowak; Robert E. III Hoehn; Allison R. Bodine; Daniel E. Crane; John F. Dwyer; Veta Bonnewell; Gary. Watson

    2013-01-01

    An analysis of trees in the Chicago region of Illinois reveals that this area has about 157,142,000 trees with tree and shrub canopy that covers 21.0 percent of the region. The most common tree species are European buckthorn, green ash, boxelder, black cherry, and American elm. Trees in the Chicago region currently store about 16.9 million tons of carbon (61.9 million...

  9. Large trees drive forest aboveground biomass variation in moist lowland forests across the tropics

    DEFF Research Database (Denmark)

    Slik, J.W.Ferry; Paoli, Gary; McGuire, Krista

    2013-01-01

    Aim Large trees (d.b.h. ≥ 70 cm) store large amounts of biomass. Several studies suggest that large trees may be vulnerable to changing climate, potentially leading to declining forest biomass storage. Here we determine the importance of large trees for tropical forest biomass storage and explore...

  10. Seeing the forest for the trees: utilizing modified random forests imputation of forest plot data for landscape-level analyses

    Science.gov (United States)

    Karin L. Riley; Isaac C. Grenfell; Mark A. Finney

    2015-01-01

    Mapping the number, size, and species of trees in forests across the western United States has utility for a number of research endeavors, ranging from estimation of terrestrial carbon resources to tree mortality following wildfires. For landscape fire and forest simulations that use the Forest Vegetation Simulator (FVS), a tree-level dataset, or “tree list”, is a...

  11. Integrating LIDAR and forest inventories to fill the trees outside forests data gap

    Science.gov (United States)

    Kristofer D. Johnson; Richard Birdsey; Jason Cole; Anu Swatantran; Jarlath O' Neil-Dunne; Ralph Dubayah; Andrew. Lister

    2015-01-01

    Forest inventories are commonly used to estimate total tree biomass of forest land even though they are not traditionally designed to measure biomass of trees outside forests (TOF). The consequence may be an inaccurate representation of all of the aboveground biomass, which propagates error to the outputs of spatial and process models that rely on the inventory data....

  12. Tree height integrated into pantropical forest biomass estimates

    NARCIS (Netherlands)

    Feldpausch, T.R.; Lloyd, J.; Lewis, S.L.; Brienen, R.J.W.; Gloor, M.; Montegudo Mendoza, A.; Arets, E.J.M.M.

    2012-01-01

    Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H). We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer

  13. A key for the Forest Service hardwood tree grades

    Science.gov (United States)

    Gary W. Miller; Leland F. Hanks; Harry V., Jr. Wiant

    1986-01-01

    A dichotomous key organizes the USDA Forest Service hardwood tree grade specifications into a stepwise procedure for those learning to grade hardwood sawtimber. The key addresses the major grade factors, tree size, surface characteristics, and allowable cull deductions in a series of paried choices that lead the user to a decision regarding tree grade.

  14. Faunal diversity of Fagus sylvatica forests: A regional and European perspective based on three indicator groups

    Directory of Open Access Journals (Sweden)

    H. Walentowski

    2014-12-01

    Full Text Available While the postglacial history of European beech (Fagus sylvatica and the plant species composition of beech forests in  Central Europe are fairly well understood, the faunal biodiversity has been less well investigated. We studied three groups of  mostly sedentary organisms in beech forest at regional and European scales by combining field studies with a compilation of existing literature and expert knowledge. Specifically, we examined the relationship between host tree genera and saproxylic  beetles, and the diversity and composition of forest ground-dwelling molluscs and ground beetles in relation to the abundance  of beech. At a west central European scale (Germany, where beech has a “young” ecological and biogeographical history,  we found 48 primeval forest relict species of saproxylic beetles associated with beech, 124 ground beetles and 91 molluscs  inhabiting beech forest, yet none exclusive of west central European beech forests. High levels of faunal similarity between beech and other woodland trees suggested that many of the beech forest dwelling species are euryoecious and likely to  originate from mid-Holocene mixed broadleaf forests. Beech forests of the mountain ranges in southern and east central  Europe, which are ecologically and biogeographically “old”, were found to harbour distinct species assemblages, including  beech forest specialists (such as 10 carabid species in the Carpathians and narrow-range endemics of broadleaf forest. The  observed biodiversity patterns suggest differentiated conservation priorities in “young” and “old” European beech forest  regions.

  15. Realizing Mitigation Efficiency of European Commercial Forests by Climate Smart Forestry.

    Science.gov (United States)

    Yousefpour, Rasoul; Augustynczik, Andrey Lessa Derci; Reyer, Christopher P O; Lasch-Born, Petra; Suckow, Felicitas; Hanewinkel, Marc

    2018-01-10

    European temperate and boreal forests sequester up to 12% of Europe's annual carbon emissions. Forest carbon density can be manipulated through management to maximize its climate mitigation potential, and fast-growing tree species may contribute the most to Climate Smart Forestry (CSF) compared to slow-growing hardwoods. This type of CSF takes into account not only forest resource potentials in sequestering carbon, but also the economic impact of regional forest products and discounts both variables over time. We used the process-based forest model 4 C to simulate European commercial forests' growth conditions and coupled it with an optimization algorithm to simulate the implementation of CSF for 18 European countries encompassing 68.3 million ha of forest (42.4% of total EU-28 forest area). We found a European CSF policy that could sequester 7.3-11.1 billion tons of carbon, projected to be worth 103 to 141 billion euros in the 21st century. An efficient CSF policy would allocate carbon sequestration to European countries with a lower wood price, lower labor costs, high harvest costs, or a mixture thereof to increase its economic efficiency. This policy prioritized the allocation of mitigation efforts to northern, eastern and central European countries and favored fast growing conifers Picea abies and Pinus sylvestris to broadleaves Fagus sylvatica and Quercus species.

  16. The western gulf forest tree improvement program, history and organization

    Science.gov (United States)

    J.P. Van Buijtenen

    1973-01-01

    The following remarks are primarily an account of the experience of the Texas Forest Service in organizing the Western Gulf Forest Tree Improvement Program (WGFTIP) and the philosophy that went into its devetopment. The program of the Texas Forest Service has had two very distinct phases, although in both phases it was a cooperative effort. The initial phase lasted...

  17. tree structural and species diversities in okwangwo forest, cross river

    African Journals Online (AJOL)

    Tersor

    ABSTRACT. For sound forest management decisions, appraisal of flora species and forest structure is crucial for any meaningful .... the study area. TREE STRUCTURAL AND SPECIES DIVERSITIES IN OKWANGWO FOREST, CROSS RIVER STATE, NIGERIA ..... architecture to absorb nutrients for growth. This is in line with ...

  18. EAB induced tree mortality impacts ecosystem respiration and tree water use in an experimental forest

    Science.gov (United States)

    Charles E. Flower; Douglas J. Lynch; Kathleen S. Knight; Miquel A. Gonzales-Meler

    2011-01-01

    The invasive emerald ash borer (Agrilus planipennis Fairmaire, EAB) has been spreading across the forest landscape of the Midwest resulting in the rapid decline of ash trees (Fraxinus spp.). Ash trees represent a dominant riparian species in temperate deciduous forests of the Eastern United States (USDA FIA Database). Prior...

  19. Adaptive genetic potential of coniferous forest tree species under climate change: implications for sustainable forest management

    Science.gov (United States)

    Mihai, Georgeta; Birsan, Marius-Victor; Teodosiu, Maria; Dumitrescu, Alexandru; Daia, Mihai; Mirancea, Ionel; Ivanov, Paula; Alin, Alexandru

    2017-04-01

    Mountain ecosystems are extremely vulnerable to climate change. The real potential for adaptation depends upon the existence of a wide genetic diversity in trees populations, upon the adaptive genetic variation, respectively. Genetic diversity offers the guarantee that forest species can survive, adapt and evolve under the influence of changing environmental conditions. The aim of this study is to evaluate the genetic diversity and adaptive genetic potential of two local species - Norway spruce and European silver fir - in the context of regional climate change. Based on data from a long-term provenance experiments network and climate variables spanning over more than 50 years, we have investigated the impact of climatic factors on growth performance and adaptation of tree species. Our results indicate that climatic and geographic factors significantly affect forest site productivity. Mean annual temperature and annual precipitation amount were found to be statistically significant explanatory variables. Combining the additive genetic model with the analysis of nuclear markers we obtained different images of the genetic structure of tree populations. As genetic indicators we used: gene frequencies, genetic diversity, genetic differentiation, genetic variance, plasticity. Spatial genetic analyses have allowed identifying the genetic centers holding high genetic diversity which will be valuable sources of gene able to buffer the negative effects of future climate change. Correlations between the marginal populations and in the optimal vegetation, between the level of genetic diversity and ecosystem stability, will allow the assessment of future risks arising from current genetic structure. Therefore, the strategies for sustainable forest management have to rely on the adaptive genetic variation and local adaptation of the valuable genetic resources. This work was realized within the framework of the project GENCLIM (Evaluating the adaptive potential of the main

  20. Soil respiration and rates of soil carbon turnover differ among six common European tree species

    DEFF Research Database (Denmark)

    Vesterdal, Lars; Elberling, Bo; Christiansen, Jesper Riis

    2012-01-01

    The knowledge of tree species effects on soil organic carbon (C) turnover based on rigorous experimental designs is limited for common European deciduous tree species. We assessed soil respiration, and rates of C turnover in six tree species in a more than 30-year-old common garden experiment...... of C turnover were estimated by (i) the ratio of estimated soil heterotrophic respiration (R h) to C stock in forest floor and top mineral soil, (ii) the ratio of litterfall C to forest floor C, (iii) foliar mass loss in litterbags, and (iv) mineral soil C turnover assessed by laboratory incubation....... Soil respiration differed significantly among several species and increased in the order beechSoil respiration was temperature limited with no significant species difference in Q10. Norway spruce soils were significantly driest, and soil respiration was also limited by soil...

  1. Fighting over forest: interactive governance of conflicts over forest and tree resources in Ghana’s high forest zone

    NARCIS (Netherlands)

    Derkyi, M.A.A.

    2012-01-01

    Based on eight case studies, this book analyses conflicts over forests and trees in Ghana’s high forest zone and ways of dealing with them. It thereby addresses the full range of forest and tree-based livelihoods. Combining interactive governance theory with political ecology and conflict theories,

  2. 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

  3. EU-Forest, a high-resolution tree occurrence dataset for Europe

    Science.gov (United States)

    Mauri, Achille; Strona, Giovanni; San-Miguel-Ayanz, Jesús

    2017-01-01

    We present EU-Forest, a dataset that integrates and extends by almost one order of magnitude the publicly available information on European tree species distribution. The core of our dataset (~96% of the occurrence records) came from an unpublished, large database harmonising forest plot surveys from National Forest Inventories on an INSPIRE-compliant 1 km×1 km grid. These new data can potentially benefit several disciplines, including forestry, biodiversity conservation, palaeoecology, plant ecology, the bioeconomy, and pest management.

  4. Spatial distribution of whole-tree carbon stocks and fluxes across the forests of Europe: where are the options for bio-energy?

    NARCIS (Netherlands)

    Nabuurs, G.J.; Schelhaas, M.J.

    2003-01-01

    This paper presents carbon stocks and fluxes of the whole-tree biomass of European forests and other wooded land, distinguished by coniferous, deciduous and mixed forests. The results are presented at the European, national and (where possible) regional level. Results concerning carbon stocks, and

  5. Sustaining America's urban trees and forests: a Forests on the Edge report

    Science.gov (United States)

    David J. Nowak; Paula B. Randler; Eric J. Greenfield; Sara J. Comas; Mary A. Carr; Ralph J. Alig

    2010-01-01

    Close to 80 percent of the U.S. population lives in urban areas and depends on the essential ecological, economic, and social benefits provided by urban trees and forests. However, the distribution of urban tree cover and the benefits of urban forests vary across the United States, as do the challenges of sustaining this important resource. As urban areas expand...

  6. Where are the trees outside forest in Brazil?

    Directory of Open Access Journals (Sweden)

    Hubert de Foresta

    2017-09-01

    Full Text Available Trees outside forests (ToF is often a misunderstood category. This is the case in Brazil as shown by the lack of data on ToF reported until now by the country. In this article, ToF are understood in relation to the FAO definition of forest because it is the definition used in Brazil for the National Forest Inventory. I provide a definition of ToF, detail the main sets as inferred from this definition, propose to focus on a category of ToF as an efficient and realistic first step towards the assessment of ToF countrywide, and I illustrate the diversity of ToF-based systems in Brazil, from relatively isolated trees in agroforestry fields to dense mixed tree formations that cannot be distinguished from forests on satellite images. A recent publication has placed Brazil as the world leader in terms of the total biomass carbon stored by one ToF set, trees on agricultural land. This result could stimulate the desire for Brazil to better assess not only trees on agricultural land but also trees on urban land, the two major sets of trees outside forests. The present paper can help those who will undertake this challenging and exciting task.

  7. Scientometrics of Forest Health and Tree Diseases: An Overview

    Directory of Open Access Journals (Sweden)

    Marco Pautasso

    2016-01-01

    Full Text Available Maintaining forest health is a worldwide challenge due to emerging tree diseases, shifts in climate conditions and other global change stressors. Research on forest health is thus accumulating rapidly, but there has been little use of scientometric approaches in forest pathology and dendrology. Scientometrics is the quantitative study of trends in the scientific literature. As with all tools, scientometrics needs to be used carefully (e.g., by checking findings in multiple databases and its results must be interpreted with caution. In this overview, we provide some examples of studies of patterns in the scientific literature related to forest health and tree pathogens. Whilst research on ash dieback has increased rapidly over the last years, papers mentioning the Waldsterben have become rare in the literature. As with human health and diseases, but in contrast to plant health and diseases, there are consistently more publications mentioning “tree health” than “tree disease,” possibly a consequence of the often holistic nature of forest pathology. Scientometric tools can help balance research attention towards understudied emerging risks to forest trees, as well as identify temporal trends in public interest in forests and their health.

  8. Assessment of forest fire impacts and emissions in the European Union based on the European forest fire information system

    Science.gov (United States)

    Paulo Barbosa; Andrea Camia; Jan Kucera; Giorgio Libertá; Ilaria Palumbo; Jesus San-Miguel-Ayanz; Guido Schmuck

    2009-01-01

    An analysis on the number of forest fires and burned area distribution as retrieved by the European Forest Fire Information System (EFFIS) database is presented. On average, from 2000 to 2005 about...

  9. Assessing Forest Classification in a Landscape-Level Framework: An Example from Central European Forests

    Directory of Open Access Journals (Sweden)

    Antonín Kusbach

    2017-11-01

    Full Text Available Traditional land classifications developed on the basis of what was once prevailing expert knowledge have since largely become obsolete. We assessed expert knowledge based landscape-level units delineated in central European temperate forests: Natural Forest Areas (NFA and Forest Vegetation Zones (FVZ. Our focus was determining to what degree these units reflect vegetation-environmental relationships. After considering as many as 49,000 plots with vegetation and 25,000 plots with environmental data within a territory of the Czech Republic, we analyzed 11,885 plots. We used multivariate statistics to discriminate between the landscape-level units. While NFAs performed extremely well, FVZ results were less successful. Classification of the environment provided better results than classification of vegetation for both the Hercynicum and Carpaticum phytogeographic part of the Czech Republic. Taking into account significance of the environment in our analysis, a delimitation of FVZs and similar vegetation-driven structures worldwide via explicit a priori stratification by tree species without consideration of environmental limits would not be supported by our analysis. We suggest not relying only on vegetation in classification analyses, but also including the significant environmental factors for direct classification of FVZ and units in particular in altered vegetation composition setting such as the central European forests. We propose a novel interpretation of FVZ via appropriate vegetation stratification throughout the environment used in conjunction with the zonal concept. Understanding of coarse-scaled vegetation-environmental relationships is not only fundamental in forest ecology and forest management, but is also essential for improving lower classification levels. Valuable expert knowledge should be combined with formal quantification, which is consistent with recent calls for advanced multidisciplinary ecological classifications in Europe

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

    African Journals Online (AJOL)

    The length increments of seedlings and branches, and the extension growth of specimens of different age classes of 12 forest tree species were measured on Mt Kenya between May 1992 and July 1995. Of all examined species, the camphor tree, Ocotea usambarensis showed the lowest growth rates. The growth rates of ...

  11. Factors Influencing Elephants to Destroy Forest Trees Especially ...

    African Journals Online (AJOL)

    ... Elephants to Destroy Forest Trees Especially Olea africana : The Case of Ngare Ndare ... weighs up to 120 kg and an average of 4,000 to 6,500 kg at maturity. ... This study examined factors which lead elephants to destroy trees such as ...

  12. Rapid Assessment of Tree Debris Following Urban Forest Ice Storms

    Science.gov (United States)

    Richard J. Hauer; Angela J. Hauer; Dudley R. Hartel; Jill R. Johnson

    2011-01-01

    This paper presents a rapid assessment method to estimate urban tree debris following an ice storm. Data were collected from 60 communities to quantify tree debris volumes, mostly from public rights-of-way, following ice storms based on community infrastructure, weather parameters, and urban forest structure. Ice thickness, area of a community, and street distance are...

  13. Genetic diversity and conservation of Mexican forest trees

    Science.gov (United States)

    C. Wehenkel; S. Mariscal-Lucero; J.P. Jaramillo-Correa; C.A. López-Sánchez; J.J. Vargas Hernández; C. Sáenz-Romero

    2017-01-01

    Over the last 200 years, humans have impacted the genetic diversity of forest trees. Because of widespread deforestation and over-exploitation, about 9,000 tree species are listed worldwide as threatened with extinction, including more than half of the ~600 known conifer taxa. A comprehensive review of the floristic-taxonomic literature compiled a list of 4,331...

  14. Adaptation of trees, forests and forestry to climate change

    Science.gov (United States)

    Daniel J. Chmura; Glenn T. Howe; Paul D. Anderson; Bradley J. St Clair

    2010-01-01

    Ongoing climate change will likely expose trees and forests to new stresses and disturbances during this century. Trees naturally adapt to changes in climate, but their natural adaptive ability may be compromised by the rapid changes projected for this century. In the broad sense, adaptation to climate change also includes the purposeful adaptation of human systems,...

  15. Above-ground tree outside forest (TOF) phytomass and carbon ...

    Indian Academy of Sciences (India)

    Trees outside forest (TOF) play an important role in global carbon cycling, since they are large pools of carbon as well as potential carbon sinks and sources to the atmosphere. In view of the importance of biomass estimates in the global carbon (C) cycle, the present study demonstrates the potential of the standwise tree ...

  16. The Contribution of Forests and Trees to Sustainable Diets

    Directory of Open Access Journals (Sweden)

    Danny Hunter

    2013-11-01

    Full Text Available With the growing demands from a population expected to reach 9 billion people by 2050, it is unclear how our current global food system will meet future food needs. Ensuring that all people have access to adequate and nutritious food produced in an environmentally and socio-culturally sustainable manner is one of the greatest challenges of our time. “Sustainable diets” have been proposed as a multidimensional framework to address the need for nutritious and adequate food in the context of the many challenges facing the world today: reducing poverty and hunger, improving environmental health, enhancing human well-being and health, and strengthening local food networks, sustainable livelihoods and cultural heritage. This paper examines the contribution of forests and trees to sustainable diets, covering among others, nutritional, cultural, environmental and provisioning aspects. The literature reviewed highlight major opportunities to strengthen the contribution of forest and tree foods to sustainable diets. However, several constraints need to be removed. They relate to: cultural aspects, sustainable use of non-wood forest products, organization of forest food provisioning, limited knowledge of forest food composition, challenges in adapting management of forests and trees to account for forest foods, and in integrating forest biodiversity into complex landscapes managed for multiple benefits. Finally, the paper identifies research gaps and makes recommendations to enhance the contribution of forest foods to sustainable diets through increased awareness and better integration of information and knowledge on nutritious forest foods into national nutrition strategies and programs.

  17. tree structural and species diversities in okwangwo forest, cross river

    African Journals Online (AJOL)

    Tersor

    tree species, which form the frame for other life forms. The Okwangwo forest is an area generally believed to be rich in plant and animal species, not present in other ...... Distribution and Abundance of Selected. Non-timber Forest Products in the. Takamanda National Park, Cameroon. International Journal of Biodiversity.

  18. Height-diameter allometry of tropical forest trees

    NARCIS (Netherlands)

    Feldpausch, T.R.; Banin, L.; Phillips, O.L.; Baker, T.R.; Lewis, S.L.; Quesada, C.A.; Affum-Baffoe, K.; Arets, E.J.M.M.; Berry, N.J.; Bird, M.; Brondizio, E.S.; Camargo, de P.; Chave, J.; Djagbletey, G.; Domingues, T.F.; Drescher, M.; Fearnside, P.M.; Franca, M.B.; Fyllas, N.M.; Lopez-Gonzalez, G.; Hladik, A.; Higuchi, N.; Hunter, M.O.; Iida, Y.; Salim, K.A.; Kassim, A.R.; Keller, M.; Kemp, J.; King, D.A.; Lovett, J.C.; Marimon, B.S.; Marimon-Junior, B.H.; Lenza, E.; Marshall, A.R.; Metcalfe, D.J.; Mitchard, E.T.A.; Moran, E.F.; Nelson, B.W.; Nilus, R.; Nogueira, E.M.; Palace, M.; Patino, S.; Peh, K.S.H.; Raventos, M.T.; Reitsma, J.M.; Saiz, G.; Schrodt, F.; Sonké, B.; Taedoumg, H.E.; Tan, S.; White, L.; Wöll, H.; Lloyd, J.

    2010-01-01

    Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955

  19. Height-diameter allometry of tropical forest trees

    Science.gov (United States)

    T.R. Feldpausch; L. Banin; O.L. Phillips; T.R. Baker; S.L. Lewis; C.A. Quesada; K. Affum-Baffoe; E.J.M.M. Arets; N.J. Berry; M. Bird; E.S. Brondizio; P de Camargo; J. Chave; G. Djagbletey; T.F. Domingues; M. Drescher; P.M. Fearnside; M.B. Franca; N.M. Fyllas; G. Lopez-Gonzalez; A. Hladik; N. Higuchi; M.O. Hunter; Y. Iida; K.A. Salim; A.R. Kassim; M. Keller; J. Kemp; D.A. King; J.C. Lovett; B.S. Marimon; B.H. Marimon-Junior; E. Lenza; A.R. Marshall; D.J. Metcalfe; E.T.A. Mitchard; E.F. Moran; B.W. Nelson; R. Nilus; E.M. Nogueira; M. Palace; S. Patiño; K.S.-H. Peh; M.T. Raventos; J.M. Reitsma; G. Saiz; F. Schrodt; B. Sonke; H.E. Taedoumg; S. Tan; L. White; H. Woll; J. Lloyd

    2011-01-01

    Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical...

  20. Diseases of Forest Trees: Consequences of Exotic Ecosystems?

    Science.gov (United States)

    William J. Otrosina

    1998-01-01

    Much attention is now given to risks and impacts of exotic pest introductions in forest ecosystems. This concern is for good reason because, once introduced, an exotic pathogen or insect encounters little resistance in the native plant population and can produce catastrophic losses in relatively short periods of time. Most native fungal pathogens of forest trees have...

  1. Lianas and trees in tropical forests in south China

    NARCIS (Netherlands)

    Cai, Z.Q.

    2007-01-01

    Lianas (woody climbers) and trees are the most important life-forms in most tropical forests. In many of these forests lianas are abundant and diverse and their presence is often a key physiognomic feature. Lianas contribute substantially to the floristic, structural and functional diversity of

  2. Forest Type and Tree Characteristics Determine the Vertical Distribution of Epiphytic Lichen Biomass in Subtropical Forests

    Directory of Open Access Journals (Sweden)

    Su Li

    2017-11-01

    Full Text Available Epiphytic lichens are an important component in subtropical forests and contribute greatly to forest biodiversity and biomass. However, information on epiphytic lichens still remains scarce in forest conservation owing to the difficulty of accessing all canopy layers for direct observation. Here, epiphytic lichens were quantified on 73 whole trees in five forest types in Southwest China to clarify the vertical stratification of their biomass in subtropical forests. Lichen biomass was significantly influenced by forest type and host attributes, varying from 187.11 to 8.55 g∙tree−1 among forest types and from 289.81 to <0.01 g∙tree−1 among tree species. The vertical stratification of lichen biomass was also determined by forest type, which peaked at the top in primary Lithocarpus forest and middle-aged oak secondary forest and in the middle upper heights in other forests. Overall, the proportion of lichen biomass accounted for 73.17–100.00% of total lichen biomass on branches and 0.00–26.83% on trunks in five forests, and 64.53–100.00% and 0.00–35.47% on eight host species. Seven functional groups showed marked and various responses to tree height between and among forest types. This information improves our understanding of the distribution of epiphytic lichens in forest ecosystems and the promotion of forest management in subtropical China.

  3. Utility of tree crown condition indicators to predict tree survival using remeasured Forest Inventory and Analysis data

    Science.gov (United States)

    Randall S. Morin; Jim Steinman; KaDonna C. Randolph

    2012-01-01

    The condition of tree crowns is an important indicator of tree and forest health. Crown conditions have been evaluated during surveys of Forest Inventory and Analysis (FIA) Phase 3 (P3) plots since 1999. In this study, remeasured data from 39,357 trees in the northern United States were used to assess the probability of survival among various tree species using the...

  4. Tree species, tree genotypes and tree genotypic diversity levels affect microbe-mediated soil ecosystem functions in a subtropical forest

    Science.gov (United States)

    Purahong, Witoon; Durka, Walter; Fischer, Markus; Dommert, Sven; Schöps, Ricardo; Buscot, François; Wubet, Tesfaye

    2016-11-01

    Tree species identity and tree genotypes contribute to the shaping of soil microbial communities. However, knowledge about how these two factors influence soil ecosystem functions is still lacking. Furthermore, in forest ecosystems tree genotypes co-occur and interact with each other, thus the effects of tree genotypic diversity on soil ecosystem functions merit attention. Here we investigated the effects of tree species, tree genotypes and genotypic diversity levels, alongside soil physicochemical properties, on the overall and specific soil enzyme activity patterns. Our results indicate that tree species identity, tree genotypes and genotypic diversity level have significant influences on overall and specific soil enzyme activity patterns. These three factors influence soil enzyme patterns partly through effects on soil physicochemical properties and substrate quality. Variance partitioning showed that tree species identity, genotypic diversity level, pH and water content all together explained ~30% variations in the overall patterns of soil enzymes. However, we also found that the responses of soil ecosystem functions to tree genotypes and genotypic diversity are complex, being dependent on tree species identity and controlled by multiple factors. Our study highlights the important of inter- and intra-specific variations in tree species in shaping soil ecosystem functions in a subtropical forest.

  5. Utilization of Biotechnology on Some Forest Trees in Turkey

    Directory of Open Access Journals (Sweden)

    Esra Nurten Yer

    2014-12-01

    Full Text Available Background and Purpose: Raw wood material requirements are increasing with rapid population growth both in Turkey and in the world. In order to supply deficit for closure of forest products, productivity and quality of production should be improved. Basic ways to increase efficiency in forest production involves silvicultural implementations and classical tree breeding studies. Genetic variation can be increased by utilizing the existing diversity. Thus, new combinations can be obtained and we can raise efficiency using some selection strategies. At this point, biotechnological methods are required to meet the genetic material. Studies of forest tree breeding are a slow process due to the size of the genome and the length of the tree life span. Biotechnological applications in forest trees provide many important benefits in terms of time saving and reducing cost when compared to classical breeding studies. Sustainable forestry practices are gaining rapid acceleration via biotechnology and modern sciences practices. In this study, for some forest tree species in Turkey, the evaluated biotechnology methods included; 1- tissue culture and clonal propagation, 2- molecular marker applications, 3- marker assisted selection and breeding, 4-genomic and proteomic studies, 5- genetic modification and genetic engineering applications. Conclusions: In this study, the works were carried out on forest tree breeding/propagation in Turkey and it was mainly focused on vegetative production techniques with 25 broadleaves and 9 conifer taxa, which were possible to express. Molecular genetic studies were carried out on 12 broad leaves taxa and 9 conifer taxa; genetic transformation studies were conducted on poplar species. Thus, it might be suggested that a combination of biotechnological tools and traditional propagation methods will ensure advantage for the development of forest-tree species.

  6. Forest Management Influences Aboveground Carbon and Tree Species Diversity in Myanmar’s Mixed Deciduous Forests

    Directory of Open Access Journals (Sweden)

    Kyaw Sein Win Tun

    2016-09-01

    Full Text Available Declines in the global extent and condition of tropical forests have reduced carbon storage potential and caused biodiversity loss. However, the magnitude of these problems within individual countries may depend on the extent of the reserved forest estate, and the particular rules put in place to manage resource use in these areas. To test this hypothesis, aboveground carbon stocks and indices of tree diversity were derived for two reserved (highly regulated sites and a protected public (less regulated site in the mixed deciduous forests of Myanmar. Aboveground tree carbon stocks were around three times higher in the reserved forests than in the public forest, a difference driven by the near absence of trees >40 cm DBH at the public forest site. The species composition of large (≥20 cm DBH trees differed substantially between all three sites. In contrast, the species composition of small (<20 cm DBH trees differed between the reserved and public forest in the case of one reserved site but not the other. Both species richness and diversity of large (≥20 cm DBH trees was about five times higher in the reserved forest than in the public forest. This was not the case for small (<20 cm DBH trees, where estimates of both richness and diversity were similar at all three sites. These findings suggest that both carbon storage potential and large-tree diversity are influenced by forest protection status. This has important implications for national carbon storage estimates as forest protection status is not currently considered as part of the standard carbon accounting procedure.

  7. Future of the Main Important Forest Tree Species in Serbia from the Climate Change Perspective

    Directory of Open Access Journals (Sweden)

    Dejan B. Stojanović

    2014-12-01

    Full Text Available Background and Purpose: Climate change is possibly the biggest 21st century challenge for the European forestry. Serbia is also under pressure, since the regions of South Europe and Mediterranean are expected to suffer the most. Main purpose of this study was to predict how distribution of several tree species in Serbia may change in the future. Materials and Methods: Our study integrates climate change scenarios for the region of Serbia together with the current distribution of forest tree species. Evaluation was performed using forest aridity index which takes into account mean temperatures and sums of precipitation of the critical months during the growing season. Distribution data of the nine most abundant tree species in Serbia (European beech, Turkey oak, Sessile oak, Hungarian oak, Pedunculate oak, Norway spruce, Silver fir, Black and Scots pine were taken from the National Forest Inventory. Results: Significant change of bioclimatic niches is expected for the majority of the studied tree species. The most endangered will be Pedunculate oak due to the extreme change of its habitats, while drought prone species (like pines and Hungarian oak will be less endangered. Sessile oak, Turkey oak, Silver fir, Norway spruce and European beech will be out of their 20th century bioclimatic niches before the end of 21st century according to A2 scenario. Conclusion: Our results suggest that some of the most important tree species in Serbia (Sessile oak, Turkey oak, Silver fir, Norway spruce and European beech will be endangered by the end of 21st century. General adaption options and specific measurements for forestry sector have to be made for the region of southeast Europe due to the expected extreme change in climate.

  8. Range image segmentation for tree detection in forest scans

    Directory of Open Access Journals (Sweden)

    A. Bienert

    2013-10-01

    Full Text Available To make a tree-wise analysis inside a forest stand, the trees have to be identified. An interactive segmentation is often labourintensive and time-consuming. Therefore, an automatic detection process will aspired using a range image. This paper presents a method for the segmentation of range images extracted from terrestrial laser scanner point clouds of forest stands. After range image generation the segmentation is carried out with a connectivity analysis using the differences of the range values as homogeneity criterion. Subsequently, the tree detection is performed interactively by analysing one horizontal image line. When passing objects with a specific width, the object indicates a potential tree. By using the edge points of a segmented pixel group the tree position and diameter is calculated. Results from one test site are presented to show the performance of the method.

  9. Tree biomass in the Swiss landscape: nationwide modelling for improved accounting for forest and non-forest trees.

    Science.gov (United States)

    Price, B; Gomez, A; Mathys, L; Gardi, O; Schellenberger, A; Ginzler, C; Thürig, E

    2017-03-01

    Trees outside forest (TOF) can perform a variety of social, economic and ecological functions including carbon sequestration. However, detailed quantification of tree biomass is usually limited to forest areas. Taking advantage of structural information available from stereo aerial imagery and airborne laser scanning (ALS), this research models tree biomass using national forest inventory data and linear least-square regression and applies the model both inside and outside of forest to create a nationwide model for tree biomass (above ground and below ground). Validation of the tree biomass model against TOF data within settlement areas shows relatively low model performance (R 2 of 0.44) but still a considerable improvement on current biomass estimates used for greenhouse gas inventory and carbon accounting. We demonstrate an efficient and easily implementable approach to modelling tree biomass across a large heterogeneous nationwide area. The model offers significant opportunity for improved estimates on land use combination categories (CC) where tree biomass has either not been included or only roughly estimated until now. The ALS biomass model also offers the advantage of providing greater spatial resolution and greater within CC spatial variability compared to the current nationwide estimates.

  10. Ash basin reclamation with forest trees

    Energy Technology Data Exchange (ETDEWEB)

    Horton, J.H.; McMinn, J.W.

    1977-09-01

    An ash basin at the Savannah River Plant, Aiken, South Carolina is growing trees as well as, and with some species better than, a local soil. The basin contains ashes from a stoker-fed boiler and was last used about 12 years before the trees were planted. The concentrations of 24 chemical elements were measured in ashes, soil and trees. The concentrations of most of the chemical elements were higher in ashes than in soil; however, with a few exceptions, these elements were less available to the trees on ashes than to the trees on soil. The trees do not show any toxicity or deficiency symptoms, but the concentration of manganese in sycamore growing on ashes indicates a possible deficiency. No concentration of an element in trees appears to be high enough to be toxic to the trees. A longer period of study will be required to determine whether the ashes can produce commercial timber, but trees can be used to stabilize ash basins and improve their appearance.

  11. Compensatory value of an urban forest: an application of the tree-value formula

    Science.gov (United States)

    David J. Nowak

    1993-01-01

    Understanding the value of an urban forest can give decisionmakers a better foundation for urban tree management. According to the tree-valuation formula of the Council of Tree and Landscape Appraisers, the estimated compensatory value of the urban forest in Oakland, California, (21% tree cover) is $385.7 million, with residential trees accounting for 58.6% of the...

  12. Effects of Drought and Rewetting on Growth and Gas Exchange of Minor European Broadleaved Tree Species

    Directory of Open Access Journals (Sweden)

    Jörg Kunz

    2016-10-01

    Full Text Available Widespread and economically important European tree species such as Norway spruce, Scots pine, and European beech are projected to be negatively affected by the increasing intensity and frequency of dry and hot conditions in a future climate. Hence, there is an increasing need to investigate the suitability of presumably more drought tolerant species to ensure future ecological stability, biodiversity, and productivity of forests. Based on their distribution patterns and climatic envelopes, the rare, minor broadleaved tree species Sorbus torminalis ((L. CRANTZ, S. domestica (L., Acer campestre (L., and A. platanoides (L. are assumed to be drought tolerant, however, there is only limited experimental basis to support that notion. This study aimed at quantifying growth and gas exchange of seedlings of these species during drought conditions, and their capacity to recover following drought. For that purpose, they were compared to the common companion species Quercus petraea ((MATTUSCHKA LIEBL. and Fagus sylvatica (L.. Here, potted seedlings of these species were exposed to water limitation followed by rewetting cycles in a greenhouse experiment. Photosynthesis and transpiration rates, stomatal conductance as well as root and shoot growth rates indicated a high drought resistance of A. campestre and A. platanoides. Sorbus domestica showed a marked ability to recover after drought stress. Therefore, we conclude that these minor tree species have the potential to enrich forests on drought-prone sites. Results from this pot experiment need to be complemented by field studies, in which the drought response of the species is not influenced by restrictions to root development.

  13. Analysing Atmospheric Processes and Climatic Drivers of Tree Defoliation to Determine Forest Vulnerability to Climate Warming

    Directory of Open Access Journals (Sweden)

    Raúl Sánchez-Salguero

    2016-12-01

    Full Text Available Crown defoliation is extensively monitored across European forests within the International Co-operative Programme (ICP as a proxy of forest health. Climate warming and drought are assumed to be the major drivers of tree growth and crown defoliation, particularly in seasonally dry areas such as the Mediterranean Basin. Here we analyse how climate, drought, and atmospheric processes are related to defoliation time series of five oak and five pine species that are dominant across Spanish ICP monitoring forest plots. We found that warmer and drier conditions during April were linked to enhanced defoliation. Warm April conditions were also related to high values of the Atlantic Multi-decadal Oscillation (AMO, thereby indicating large-scale links between atmospheric processes, temperature, and defoliation patterns. The temperature-defoliation association was species-specific since some tree species from wet sites showed a weak association (e.g., Quercus robur L. whereas others from dry sites (e.g., Quercus ilex L. presented the strongest associations. The latter tree species could be considered vulnerable to heat stress in terms of leaf shedding. We also explored if defoliation was related to radial growth and found negative associations in relatively dry areas. Warmer and drier conditions linked to increasing AMO values are connected to the post-1990s rise of defoliation in Spanish ICP forest plots. Combined incorporation of defoliation and growth into mortality models can provide insights into assessments of forest vulnerability.

  14. Seeing the forest for the trees

    DEFF Research Database (Denmark)

    Ribbons, Relena Rose

    Tree species influence soils above and belowground communities through leaf litter and root inputs. Soil microbial communities can directly influence tree growth and development through processes such as decomposition of leaves, and indirectly through chemical transformation of nutrients in soils...... as an influence of altered C:N ratios due to leaf litter inputs. This thesis aims to document some of the mechanisms by which trees influence soil microbial communities and nitrogen cycling processes like gross and net ammonification and nitrification. This thesis also aims to determine the role of site nitrogen...

  15. Tree age, disturbance history, and carbon stocks and fluxes in subalpine Rocky Mountain forests

    Science.gov (United States)

    J.B. Bradford; R.A. Birdsey; L.A. Joyce; M.G. Ryan

    2008-01-01

    Forest carbon stocks and fluxes vary with forest age, and relationships with forest age are often used to estimate fluxes for regional or national carbon inventories. Two methods are commonly used to estimate forest age: observed tree age or time since a known disturbance. To clarify the relationships between tree age, time since disturbance and forest carbon storage...

  16. Seeing the forest beyond the trees

    Science.gov (United States)

    Sassan Saatchi; Joseph Mascaro; Liang Xu; Michael Keller; Yan Yang; Paul Duffy; Fernando Espirito-Santo; Alessandro Baccini; Jeffery Chambers; David Schimel

    2014-01-01

    In a recent paper (Mitchard et al. 2014, Global Ecology and Biogeography, 23,935-946) a new map of forest biomass based on a geostatistical model of field data for the Amazon (and surrounding forests) was presented and contrasted with two earlier maps based on remote sensing data Saatchi et al. (2011; RS1) and Baccini et al. (2012; RS2). Mitchard et al....

  17. Nitrous oxide fluxes from forest floor, tree stems and canopies of boreal tree species during spring

    Science.gov (United States)

    Haikarainen, Iikka; Halmeenmäki, Elisa; Machacova, Katerina; Pihlatie, Mari

    2017-04-01

    Boreal forests are considered as small sources of atmospheric nitrous oxide (N2O) due to microbial N2O production in the soils. Recent evidence shows that trees may play an important role in N2O exchange of forest ecosystems by offering pathways for soil produced N2O to the atmosphere. To confirm magnitude, variability and the origin of the tree mediated N2O emissions more research is needed, especially in boreal forests which have been in a minority in such investigation. We measured forest floor, tree stem and shoot N2O exchange of three boreal tree species at the beginning of the growing season (13.4.-13.6.2015) at SMEAR II station in Hyytiälä, located in Southern Finland (61˚ 51´N, 24˚ 17´E, 181 a.s.l.). The fluxes were measured in silver birch (Betula pendula), downy birch (B. pubescens) and Norway spruce (Picea abies) on two sites with differing soil type and characteristics (paludified and mineral soil), vegetation cover and forest structure. The aim was to study the vertical profile of N2O fluxes at stem level and to observe temporal changes in N2O fluxes over the beginning of the growing season. The N2O exchange was determined using the static chamber technique and gas chromatographic analyses. Scaffold towers were used for measurements at multiple stem heights and at the canopy level. Overall, the N2O fluxes from the forest floor and trees at both sites were very small and close to the detection limit. The measured trees mainly emitted N2O from their stems and shoots, while the forest floor acted as a sink of N2O at the paludified site and as a small source of N2O at the mineral soil site. Stem emissions from all the trees at both sites were on average below 0.5 μg N2O m-2 of stem area h-1, and the shoot emissions varied between 0.2 and 0.5 ng N2O m-2 g-1 dry biomass. When the N2O fluxes were scaled up to the whole forest ecosystem, based on the tree biomass and stand density, the N2O emissions from birch and spruce trees at the paludified site

  18. 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.

  19. 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.

  20. Risk of genetic maladaptation due to climate change in three major European tree species.

    Science.gov (United States)

    Frank, Aline; Howe, Glenn T; Sperisen, Christoph; Brang, Peter; Clair, J Bradley St; Schmatz, Dirk R; Heiri, Caroline

    2017-12-01

    Tree populations usually show adaptations to their local environments as a result of natural selection. As climates change, populations can become locally maladapted and decline in fitness. Evaluating the expected degree of genetic maladaptation due to climate change will allow forest managers to assess forest vulnerability, and develop strategies to preserve forest health and productivity. We studied potential genetic maladaptation to future climates in three major European tree species, Norway spruce (Picea abies), silver fir (Abies alba), and European beech (Fagus sylvatica). A common garden experiment was conducted to evaluate the quantitative genetic variation in growth and phenology of seedlings from 77 to 92 native populations of each species from across Switzerland. We used multivariate genecological models to associate population variation with past seed source climates, and to estimate relative risk of maladaptation to current and future climates based on key phenotypic traits and three regional climate projections within the A1B scenario. Current risks from climate change were similar to average risks from current seed transfer practices. For all three climate models, future risks increased in spruce and beech until the end of the century, but remained low in fir. Largest average risks associated with climate projections for the period 2061-2090 were found for spruce seedling height (0.64), and for beech bud break and leaf senescence (0.52 and 0.46). Future risks for spruce were high across Switzerland. However, areas of high risk were also found in drought-prone regions for beech and in the southern Alps for fir. Genetic maladaptation to future climates is likely to become a problem for spruce and beech by the end of this century, but probably not for fir. Consequently, forest management strategies should be adjusted in the study area for spruce and beech to maintain productive and healthy forests in the future. © 2017 John Wiley & Sons Ltd.

  1. Tree species Diversity in the Department of Forest Resources ...

    African Journals Online (AJOL)

    Trees, which are important for the sustenance of life and the health of our planet, are disappearing at an alarming rate. Consequently, the need for actions to develop effective strategies to conserve them is receiving considerable attention worldwide. Forest genetic resources are fast becoming depleted in most natural ...

  2. Measuring Tree Seedlings and Associated Understory Vegetation in Pennsylvania's Forests

    Science.gov (United States)

    William H. McWilliams; Todd W. Bowersox; Patrick H. Brose; Daniel A. Devlin; James C. Finley; Kurt W. Gottschalk; Steve Horsley; Susan L. King; Brian M. LaPoint; Tonya W. Lister; Larry H. McCormick; Gary W. Miller; Charles T. Scott; Harry Steele; Kim C. Steiner; Susan L. Stout; James A. Westfall; Robert L. White

    2005-01-01

    The Northeastern Research Station's Forest Inventory and Analysis (NE-FIA) unit is conducting the Pennsylvania Regeneration Study (PRS) to evaluate composition and abundance of tree seedlings and associated vegetation. Sampling methods for the PRS were tested and developed in a pilot study to determine the appropriate number of 2-m microplots needed to capture...

  3. Spatial-temporal changes in trees outside forests

    DEFF Research Database (Denmark)

    Novotný, M.; Skaloš, J.; Plieninger, T.

    2017-01-01

    the spatial-temporal dynamics of different subcategories of trees outside forests in context with land cover changes of the Czech Republic. The analysis is based on the re-evaluation of change trajectories of individual landscape elements. Historical black and white aerial photographs from 1953 and colour...

  4. Forest and fibre genomics: biotechnology tools for applied tree ...

    African Journals Online (AJOL)

    This paper provides a brief overview of research progress in the WFMG programme and discusses realistic time frames for the delivery of genome-based tree improvement tools. Keywords: biotechnology; cellulose; Eucalyptus; fibre; gene discovery; genomics; marker-assisted breeding; wood development. Southern Forests ...

  5. Propagation of dry tropical forest trees in Mexico

    Science.gov (United States)

    Martha A. Cervantes Sanchez

    2002-01-01

    There is a distinct lack of technical information on the propagation of native tree species from the dry tropical forest ecosystem in Mexico. This ecosystem has come under heavy human pressures to obtain several products such as specialty woods for fuel, posts for fences and construction, forage, edible fruits, stakes for horticulture crops, and medicinal products. The...

  6. Modelling of Climate Conditions in Forest Vegetation Zones as a Support Tool for Forest Management Strategy in European Beech Dominated Forests

    Directory of Open Access Journals (Sweden)

    Ivo Machar

    2017-03-01

    Full Text Available The regional effects of climate change on forest ecosystems in the temperate climate zone of Europe can be modelled as shifts of forest vegetation zones in the landscape, northward and to higher elevations. This study applies a biogeographical model of climate conditions in the forest vegetation zones of the Central European landscape, in order to predict the impact of future climate change on the most widespread tree species in European deciduous forests—the European beech (Fagus sylvatica L.. The biogeographical model is supported by a suite of software applications in the GIS environment. The model outputs are defined as a set of conditions - climate scenario A1B by the Special Report on Emission Scenarios (SRES for a forecast period, for a specified geographical area and with ecological conditions appropriate for the European beech, which provide regional scenarios for predicted future climatic conditions in the context of the European beech’s environmental requirements. These predicted changes can be graphically visualized. The results of the model scenarios for regional climate change show that in the Czech Republic from 2070 onwards, optimal growing conditions for the European beech will only exist in some parts of those areas where it currently occurs naturally. Based on these results, it is highly recommended that the national strategy for sustainable forest management in the Czech Republic be partly re-evaluated. Thus, the presented biogeographical model of climate conditions in forest vegetation zones can be applied, not only to generate regional scenarios of climate change in the landscape, but also as a support tool for the development of a sustainable forest management strategy.

  7. Inorganic chemical composition of native trees of the Atlantic Forest.

    Science.gov (United States)

    De França, E J; De Nadai Fernandes, E A; Bacchi, M A; Rodrigues, R R; Verburg, T G

    2005-03-01

    The Atlantic Forest with its exuberant vegetation of high level of biodiversity is classified as one hotspot of the world. Chemical composition of leaves from native trees and underlying soils was evaluated by INAA. The predominant species Euterpe edulis, Bathysa meridionalis, Hyeronima alchorneoides, Marlierea tomentosa, Gomidesia flagellaris, and Gomidesia spectabilis belonging to the diverse plant families were studied. Euterpe edulis, the most abundant understory specie, presented the lowest element concentrations except for Zn. Some variation in chemical composition was noted, however, the chemical specificity of tree species can be more predominant than the soil variability for the obtained leaf concentrations. Factor values obtained through the Monte-Carlo assisted factor analysis were used for species discrimination, The results indicate that chemical investigation of native trees is a quite promising tool for biodiversity studies in the Atlantic Forest.

  8. Tree Species Composition and Regeneration Status of Shitalpur Forest Beat under Chittagong North Forest Division, Bangladesh

    Directory of Open Access Journals (Sweden)

    Asadozzaman Nur

    2016-01-01

    Full Text Available Biodiversity erosion particularly in developing countries is a matter of great concern to the global ecological community. Species composition and regeneration indicate the health of forest. This study explored tree species composition and regeneration of natural hill forest of Shitalpur under Chittagong North Forest Division through 27 sample plots of 20 m × 20 m for trees and 2 m × 2 m for regeneration. A total of 47 tree species belonging to 29 families and 17 regenerating species belonging to 15 families were recorded. The tree stem density, basal area, and wood volume were 0.49 m2/ha, 1425 stem/ha, and 189.9 m3/ha, respectively. Mean regeneration was significantly higher in bottom hill (14374 seedlings/ha compared to top hill (9671 seedlings/ha. Toona ciliata was highest (4444 seedlings/ha at the bottom hill compared to other hill positions. The result shows that only 36% of the tree species (17 out of 47 are regenerating in the study area, meaning majority of the tree species (64% are not getting favorable conditions to regenerate. This might be due to absence of mature tree species as a result of overexploitation by local people. The findings may help in monitoring the species composition changes over time and adopting specific conservation programs for Shitalpur Forest.

  9. The importance of Ficus (Moraceae) trees for tropical forest restoration

    DEFF Research Database (Denmark)

    Cottee-Jones, H. Eden W.; Bajpai, Omesh; Chaudhary, Lal B.

    2016-01-01

    Forest restoration is an increasingly important tool to offset and indeed reverse global deforestation rates. One low cost strategy to accelerate forest recovery is conserving scattered native trees that persist across disturbed landscapes and which may act as seedling recruitment foci. Ficus trees...... restoration agents than other remnant trees in disturbed landscapes, and therefore the conservation of these trees should be prioritized....

  10. Nitrous oxide fluxes from tree stems of temperate forests

    Science.gov (United States)

    Wen, Yuan; Corre, Marife D.; Rachow, Christine; Veldkamp, Edzo

    2017-04-01

    Although trees are recognized as conduits of soil-generated N2O, little is known about N2O fluxes from mature trees under field conditions and thier contributions to total forest N2O fluxes. Here, we quantified in situ stem N2O fluxes from mature alder trees on poorly-drained soil and mature beech and spruce trees on well-drained soils in Solling, Germany from March to October 2015. Soil N2O fluxes, soil N2O concentrations at 40-cm depth, and soil and climatic variables known to influence N2O fluxes were also measured concurrently with the stem N2O fluxes. Alder, beech and spruce consistently emitted N2O via stems and all displayed higher emission rates in summer than in spring and in autumn. Stem N2O fluxes from alder stand were higher than those from beech and spruce stands (P emissions in upland trees. Stem N2O fluxes represented 8-11% of the total (soil + stem) N2O fluxes in the spruce and beech stands whereas in the alder stand, with its large soil N2O emission, stem emission contributed only 1% of the total flux. Our results suggest that the relative contribution of tree-mediated N2O fluxes is more important in upland trees than in wetland trees.

  11. First sign of carbon sink saturation in European forest biomass

    NARCIS (Netherlands)

    Nabuurs, G.J.; Lindner, M.; Verkerk, P.J.; Gunia, K.; Deda, P.; Michalak, R.; Grassi, G.

    2013-01-01

    European forests are seen as a clear example of vegetation rebound in the Northern Hemisphere; recovering in area and growing stock since the 1950s, after centuries of stock decline and deforestation. These regrowing forests have shown to be a persistent carbon sink, projected to continue for

  12. Drivers of earthworm incidence and abundance across European forests

    DEFF Research Database (Denmark)

    Wandeler, Hans De; Sousa-Silva, Rita; Ampoorter, Evy

    2016-01-01

    Earthworms have a significant influence on the structure, composition and functioning of forest ecosystems, but in spite of their role as ecosystem engineers, little is known on the factors controlling their distribution across European forests. Optimised sampling techniques, as well as more adva...

  13. Forest vegetation in western Romania in relation to climate variables: Does community composition reflect modelled tree species distribution?

    Directory of Open Access Journals (Sweden)

    S. Heinrichs

    2016-12-01

    Full Text Available European beech (Fagus sylvatica L. is the prevailing tree species of mesic forests in Central Europe. Increasing summer temperatures and decreasing precipitation, as climate change scenarios predict, may, however, negatively influence beech growth and induce a shift to more thermophilous forest communities. Temperatures as expected in the future for western Central Europe are currently found in parts of western Romania. In light of this climate analogy we investigated forest vegetation as an indicator for future vegetation changes in five regions of western Romania representing a climatic gradient. We related species composition to climate variables and examined if tree and understorey species composition respond similarly to the climatic gradient. We further analysed if tree species occurrences correspond with their modelled distance to the rear niche edge. We found evidence for climatic effects on vegetation composition among regions as well as within deciduous and pine forests, respectively. This underlines that vegetation composition is a useful indicator for environmental change. Tree and understorey species compositions were closely linked showing that community-based characterization of forest stands can provide additional information on tree species suitability along environmental gradients. Both, vegetation composition and a climatic marginality index demonstrate the rear niche edge occurrence of beech in the studied sites of Romania and can predict the site suitability for different tree species. While vegetation surveys indicate Quercus petraea to be associated to moderately mesic forests, the marginality index suggested an inner niche position of sessile oak along the climatic gradient. Phytosociological relevés that differentiate between subspecies (or microspecies of sessile oak with differing habitat requirements should be considered to complement national forest inventories and species distribution maps when modelling rear

  14. Species Composition of Down Dead and Standing Live Trees: Implications for Forest Inventory Analysis

    Science.gov (United States)

    Christopher W. Woodall; Linda Nagel

    2005-01-01

    The assessment of species composition in most forest inventory analysis relies solely on standing live tree information characterized by current forest type. With the implementation of the third phase of the U.S. Department of Agriculture Forest Service's Forest Inventory and Analysis program, the species composition of down dead trees, otherwise termed coarse...

  15. Tree Regeneration in Church Forests of Ethiopia: Effects of Microsites and Management

    NARCIS (Netherlands)

    Wassie Eshete, A.; Sterck, F.J.; Teketay, D.; Bongers, F.

    2009-01-01

    Tree regeneration is severely hampered in the fragmented afromontane forests of northern Ethiopia. We explored how trees regenerate in remnant forests along the gradient from open field, forest edge to closed sites and canopy gaps inside the forest. We investigated the effects of seed sowing, litter

  16. Finding a Forest in a Tree

    DEFF Research Database (Denmark)

    Bacci, Giorgio; Miculan, Marino; Rizzi, Romeo

    2014-01-01

    Wide reactive systems are rewriting systems specified by wide reaction rules, where redex and reactum are lists of terms (forests), i.e. rules of the form ⟨l1(x1),…,ln(xn)⟩⇒⟨r1(y1),…,rn(yn)⟩ such that ∪iyi⊆∪ixi. Wide reaction rules are particularly useful for process calculi for mobile and global...

  17. Assessment of forest management influences on total live aboveground tree biomass in William B Bankhead National Forest, Alabama

    Science.gov (United States)

    Callie Schweitzer; Dawn Lemke; Wubishet Tadesse; Yong Wang

    2015-01-01

    Forests contain a large amount of carbon (C) stored as tree biomass (above and below ground), detritus, and soil organic material. The aboveground tree biomass is the most rapid change component in this forest C pool. Thus, management of forest resources can influence the net C exchange with the atmosphere by changing the amount of C stored, particularly in landscapes...

  18. Tree Nonstructural Carbohydrate Reserves Across Eastern US Temperate Forests

    Science.gov (United States)

    Mantooth, J.; Dietze, M.

    2015-12-01

    Understanding the roles, importance, and dynamics of tree non-structural carbohydrates (NSCs) is currently an active area of research. The question of how the relationships between NSCs, growth, and mortality can be used to develop more accurate projections of forest dynamics is central to this research. To begin to address this question, we have asked an even more fundamental question: How much are trees allocating carbon to storage, in the form of NSCs, versus new growth? Ecological theory predicts that there should be trade-offs between different plant life history strategies provided that there are the carbon mass-balance constraints to enforce these trade-offs. Current data on tree NSCs lack the spatial and taxonomic extent required to properly address this question. Therefore, we established a network of forest inventory plots at ten sites across the eastern US and measured growth in adult trees using increment cores and repeat measures of diameter at breast height (DBH). Increment cores were also used to measure sapwood NSCs. We hypothesized that across the eastern US, shade tolerant species, e.g. Sugar Maple (Acer saccharum) have the largest NSC reserves and that shade intolerant species have the lowest reserves. We also hypothesized that NSC reserves increase with temperature and precipitation, as with growth, and that within species NSC reserves increase with growth rate. Initial analyses of tree NSCs indicates that trees of intermediate shade tolerance, e.g. Red Oak (Quercus rubra) have the highest concentrations of sapwood NSCs, and among the highest growth rates. Across the entire study region, NSC concentrations are positively correlated with tree size and growth rate. Within species, NSC concentrations are also positively correlated with growth rate. Across functional groups healthy individuals have significantly higher sapwood NSC concentrations than visibly stressed individuals. There are also significantly lower NSC concentrations in sapwood of

  19. MetaTree: augmented reality narrative explorations of urban forests

    Science.gov (United States)

    West, Ruth; Margolis, Todd; O'Neil-Dunne, Jarlath; Mendelowitz, Eitan

    2012-03-01

    As cities world-wide adopt and implement reforestation initiatives to plant millions of trees in urban areas, they are engaging in what is essentially a massive ecological and social experiment. Existing air-borne, space-borne, and fieldbased imaging and inventory mechanisms fail to provide key information on urban tree ecology that is crucial to informing management, policy, and supporting citizen initiatives for the planting and stewardship of trees. The shortcomings of the current approaches include: spatial and temporal resolution, poor vantage point, cost constraints and biological metric limitations. Collectively, this limits their effectiveness as real-time inventory and monitoring tools. Novel methods for imaging and monitoring the status of these emerging urban forests and encouraging their ongoing stewardship by the public are required to ensure their success. This art-science collaboration proposes to re-envision citizens' relationship with urban spaces by foregrounding urban trees in relation to local architectural features and simultaneously creating new methods for urban forest monitoring. We explore creating a shift from overhead imaging or field-based tree survey data acquisition methods to continuous, ongoing monitoring by citizen scientists as part of a mobile augmented reality experience. We consider the possibilities of this experience as a medium for interacting with and visualizing urban forestry data and for creating cultural engagement with urban ecology.

  20. Effect of species composition on carbon and nitrogen stocks in forest floor and mineral soil in Norway spruce and European beech mixed forests

    Science.gov (United States)

    Andivia, Enrique; Rolo, Víctor; Jonard, Mathieu; Formánek, Pavel; Ponette, Quentin

    2015-04-01

    Management of existing forests has been identified as the main strategy to enhance carbon sequestration and to mitigate the impact of climate change on forest ecosystems. In this direction, the conversion of Norway spruce monospecific stands into mixed stands by intermingling individuals of European beech is an ongoing trend in adaptive forest management strategies, especially in Central Europe. However, studies assessing the effect of changes in tree species composition on soil organic carbon (SOC) and nitrogen stocks are still scarce and there is a lack of scientific evidence supporting tree species selection as a feasible management option to mitigate the effects of predicted future climatic scenarios. We compared C and N stocks in the forest floor (litter and humus) and the top 10 cm of mineral soil in two monospecific stands of Norway spruce and European beech and in a mixed stand of both species. The effect of tree species composition on the C and N stocks and its spatial distribution was evaluated based on litterfall, root production, elevation and canopy opening, and by using a combination of modelling and geostatistical techniques. C stock was highest in the Norway spruce and the mixed stands, while N stock was highest in the mixed stand and lowest under European beech, with intermediate values in the Norway spruce stand. Each forest type showed differences in forest floor properties, suggesting that species composition is an important factor governing forest floor characteristics, including C and N stocks. The distribution of C and N stocks between forest soil layers was different for each forest type. C and N stocks were highest in the hummus layer under Norway spruce, whereas both stocks were lowest in the European beech stand. On the other hand, the mixed stand showed the highest C and N accumulation in the uppermost mineral soil layer, while the monospecific stands showed similar values. Litterfall was the main contribution to C and N stocks of the

  1. Mapping urban forest tree species using IKONOS imagery: preliminary results.

    Science.gov (United States)

    Pu, Ruiliang

    2011-01-01

    A stepwise masking system with high-resolution IKONOS imagery was developed to identify and map urban forest tree species/groups in the City of Tampa, Florida, USA. The eight species/groups consist of sand live oak (Quercus geminata), laurel oak (Quercus laurifolia), live oak (Quercus virginiana), magnolia (Magnolia grandiflora), pine (species group), palm (species group), camphor (Cinnamomum camphora), and red maple (Acer rubrum). The system was implemented with soil-adjusted vegetation index (SAVI) threshold, textural information after running a low-pass filter, and brightness threshold of NIR band to separate tree canopies from non-vegetated areas from other vegetation types (e.g., grass/lawn) and to separate the tree canopies into sunlit and shadow areas. A maximum likelihood classifier was used to identify and map forest type and species. After IKONOS imagery was preprocessed, a total of nine spectral features were generated, including four spectral bands, three hue-intensity-saturation indices, one SAVI, and one texture image. The identified and mapped results were examined with independent ground survey data. The experimental results indicate that when classifying all the eight tree species/ groups with the high-resolution IKONOS image data, the identifying accuracy was very low and could not satisfy a practical application level, and when merging the eight species/groups into four major species/groups, the average accuracy is still low (average accuracy = 73%, overall accuracy = 86%, and κ = 0.76 with sunlit test samples). Such a low accuracy of identifying and mapping the urban tree species/groups is attributable to low spatial resolution IKONOS image data relative to tree crown size, to complex and variable background spectrum impact on crown spectra, and to shadow/shaded impact. The preliminary results imply that to improve the tree species identification accuracy and achieve a practical application level in urban area, multi-temporal (multi

  2. The impact of nitrogen deposition on carbon sequestration in European forests and forest soils

    NARCIS (Netherlands)

    Vries, de W.; Reinds, G.J.; Gundersen, P.; Sterba, H.

    2006-01-01

    An estimate of net carbon (C) pool changes and long-term C sequestration in trees and soils was made at more than 100 intensively monitored forest plots (level II plots) and scaled up to Europe based on data for more than 6000 forested plots in a systematic 16 km x 16 km grid (level I plots). C pool

  3. Aboveground tree biomass on productive forest land in Alaska.

    Science.gov (United States)

    John Yarie; Delbert. Mead

    1982-01-01

    Total aboveground woody biomass of trees on forest land that can produce 1.4 cubic m eters per hectare per year of industrial wood in Alaska is 1.33 billion metric tons green weight. The estimated energy value of the standing woody biomass is 11.9 x 10'5 Btu's. Statewide tables of biomass and energy values for softwoods, hardwoods, and species groups are...

  4. Forests, Trees, and Micronutrient-Rich Food Consumption in Indonesia.

    Directory of Open Access Journals (Sweden)

    Amy Ickowitz

    Full Text Available Micronutrient deficiency remains a serious problem in Indonesia with approximately 100 million people, or 40% of the population, suffering from one or more micronutrient deficiencies. In rural areas with poor market access, forests and trees may provide an essential source of nutritious food. This is especially important to understand at a time when forests and other tree-based systems in Indonesia are being lost at unprecedented rates. We use food consumption data from the 2003 Indonesia Demographic Health Survey for children between the ages of one and five years and data on vegetation cover from the Indonesian Ministry of Forestry to examine whether there is a relationship between different tree-dominated land classes and consumption of micronutrient-rich foods across the archipelago. We run our models on the aggregate sample which includes over 3000 observations from 25 provinces across Indonesia as well as on sub-samples from different provinces chosen to represent the different land classes. The results show that different tree-dominated land classes were associated with the dietary quality of people living within them in the provinces where they were dominant. Areas of swidden/agroforestry, natural forest, timber and agricultural tree crop plantations were all associated with more frequent consumption of food groups rich in micronutrients in the areas where these were important land classes. The swidden/agroforestry land class was the landscape associated with more frequent consumption of the largest number of micronutrient rich food groups. Further research needs to be done to establish what the mechanisms are that underlie these associations. Swidden cultivation in is often viewed as a backward practice that is an impediment to food security in Indonesia and destructive of the environment. If further research corroborates that swidden farming actually results in better nutrition than the practices that replace it, Indonesian policy

  5. Comprehensive monitoring of Bangladesh tree cover inside and outside of forests, 2000–2014

    Science.gov (United States)

    Potapov, P.; Siddiqui, B. N.; Iqbal, Z.; Aziz, T.; Zzaman, B.; Islam, A.; Pickens, A.; Talero, Y.; Tyukavina, A.; Turubanova, S.; Hansen, M. C.

    2017-10-01

    A novel approach for satellite-based comprehensive national tree cover change assessment was developed and applied in Bangladesh, a country where trees outside of forests play an important role in the national economy and carbon sequestration. Tree cover change area was quantified using the integration of wall-to-wall Landsat-based mapping with a higher spatial resolution sample-based assessment. The total national tree canopy cover area was estimated as 3165 500 ± 186 600 ha in the year 2000, with trees outside forests making up 54% of total canopy cover. Total tree canopy cover increased by 135 700 (± 116 600) ha (4.3%) during the 2000–2014 time interval. Bangladesh exhibits a national tree cover dynamic where net change is rather small, but gross dynamics significant and variable by forest type. Despite the overall gain in tree cover, results revealed the ongoing clearing of natural forests, especially within the Chittagong hill tracts. While forests decreased their tree cover area by 83 600 ha, the trees outside forests (including tree plantations, village woodlots, and agroforestry) increased their canopy area by 219 300 ha. Our results demonstrated method capability to quantify tree canopy cover dynamics within a fine-scale agricultural landscape. Our approach for comprehensive monitoring of tree canopy cover may be recommended for operational implementation in Bangladesh and other countries with significant tree cover outside of forests.

  6. High sensitivity of northeastern broadleaf forest trees to water availability

    Science.gov (United States)

    Levesque, M.; Pederson, N.; Andreu-Hayles, L.

    2015-12-01

    Temperate deciduous forests of eastern US provide goods and services to millions of people and play a vital role in the terrestrial carbon and hydrological cycles. However, ongoing climate change and increased in CO2 concentration in the atmosphere (ca) are expected to alter growth and gas exchange of trees, and ultimately forest productivity. Still, the magnitude of these effects is unclear. A better comprehension of the species-specific responses to environmental changes will better inform models and managers on the vulnerability and resiliency of these forests. Tree-ring analysis was combined with δ¹³C and δ18O measurements to investigate growth and physiological responses of red oak (Quercus rubra L.) and tulip poplar (Liriodendron tulipifera L.) in northeastern US to changes in water availability and ca for the period 1950-2014. We found very strong correlations between summer climatic water balance (June-August) and isotopic tree-ring series for δ¹³C (r = -0.65 and -0.73), and δ18O (r = -0.59 and -0.70), for red oak and tulip poplar, respectively. In contrast, tree-ring width was less sensitive to summer water availability (r = 0.33-0.39). Prior to the mid 1980s, low water availability resulted in low stomatal conductance, photosynthesis, and growth. Since that period, pluvial conditions occurring in northeastern US have increased stomatal conductance, carbon uptake, and growth of both species. These findings demonstrate that broadleaf trees in this region could be more sensitive to drought than expected. This appears especially true since much of the calibration period looks wet in a multi-centennial perspective. Further, stronger spatial correlations were found between climate data with tree-ring isotopes than with tree-ring width and the geographical area of the observed δ18O-precipitation response (i.e. the area over which correlations are > 0.5) covers most of the northeastern US. Given the good fit between the isotopic time series and water

  7. Sampling forest tree regeneration with a transect approach

    Directory of Open Access Journals (Sweden)

    D. Hessenmöller

    2013-05-01

    Full Text Available A new transect approach for sampling forest tree regeneration isdeveloped with the aim to minimize the amount of field measurements, and to produce an accurate estimation of tree species composition and density independent of tree height. This approach is based on the “probability proportional to size” (PPS theory to assess heterogeneous vegetation. This new method is compared with other approaches to assess forest regeneration based on simulated and measured, real data. The main result is that the transect approach requires about 50% of the time to assess stand density as compared to the plot approach, due to the fact that only 25% of the tree individuals are measured. In addition, tall members of the regeneration are counted with equal probability as small members. This is not the case in the plot approach. The evenness is 0.1 to 0.2 units larger in the transect by PPS than in the plot approach, which means that the plot approach shows a more homogeneous regeneration layer than the PPS approach, even though the stand densities and height distributions are similar. The species diversity is variable in both approaches and needs further investigations.

  8. Cryptic adaptive radiation in tropical forest trees in New Caledonia.

    Science.gov (United States)

    Pillon, Yohan; Hopkins, Helen C F; Rigault, Frédéric; Jaffré, Tanguy; Stacy, Elizabeth A

    2014-04-01

    The causes of the species richness of tropical trees are poorly understood, in particular the roles of ecological factors such as soil composition. The nickel(Ni)-hyperaccumulating tree genus Geissois (Cunoniaceae) from the South-west Pacific was chosen as a model of diversification on different substrates. Here, we investigated the leaf element compositions, spatial distributions and phylogeny of all species of Geissois occurring on New Caledonia. We found that New Caledonian Geissois descended from a single colonist and diversified relatively quickly into 13 species. Species on ultramafic and nonultramafic substrates showed contrasting patterns of leaf element composition and range overlap. Those on nonultramafic substrates were largely sympatric but had distinct leaf element compositions. By contrast, species on ultramafic substrates showed similar leaf element composition, but occurred in many cases exclusively in allopatry. Further, earlier work showed that at least three out of these seven species use different molecules to bind Ni. Geissois qualifies as a cryptic adaptive radiation, and may be the first such example in a lineage of tropical forest trees. Variation in biochemical strategies for coping with both typical and adverse soil conditions may help to explain the diversification and coexistence of tropical forest trees on similar soil types. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  9. Relationships between the stocking levels of live trees and dead tree attributes in forests of the United States

    Science.gov (United States)

    C.W. Woodall; J.A. Westfall

    2009-01-01

    There has been little examination of the relationship between the stocking of live trees in forests and the associated attributes of dead tree resources which could inform large-scale efforts to estimate and manage deadwood resources. The goal of this study was to examine the relationships between the stocking of standing live trees and attributes of standing dead and...

  10. Sustainable development and use of ecosystems with non-forest trees

    Science.gov (United States)

    Non-forest trees are components of managed ecosystems including orchards and agroforestry systems and natural ecosystems such as savannas and riparian corridors. Each of these ecosystems includes trees but does not have a complete tree canopy or spatial extent necessary to create a true forest ecosy...

  11. Allometry, biomass, and chemical content of novel African Tulip Tree (Spathodea campanulata) forests in Puerto Rico

    Science.gov (United States)

    Ariel E. Lugo; Oscar J. Abelleira; Alexander Collado; Christian A. Viera; Cynthia Santiago; Diego O. Velez; Emilio Soto; Giovanni Amaro; Graciela Charon; Jr. Colon; Jennifer Santana; Jose L. Morales; Katherine Rivera; Luis Ortiz; Luis Rivera; Mianel Maldonado; Natalia Rivera; Norelis J. Vazquez

    2011-01-01

    The African tulip tree, Spathodea campanulata, the most common tree in Puerto Rico, forms novel forest types with mixtures of native and other introduced tree species. Novel forests increase in area in response to human activity and there is no information about their biomass accumulation and nutrient cycling. We established allometric relationships and chemically...

  12. Trends over time in tree and seedling phylogenetic diversity indicate regional differences in forest biodiversity change

    Science.gov (United States)

    Kevin M. Potter; Christopher W. Woodall

    2012-01-01

    Changing climate conditions may impact the short-term ability of forest tree species to regenerate in many locations. In the longer term, tree species may be unable to persist in some locations while they become established in new places. Over both time frames, forest tree biodiversity may change in unexpected ways. Using repeated inventory measurements five years...

  13. Classification of Forest Management Approaches: A New Conceptual Framework and Its Applicability to European Forestry

    Directory of Open Access Journals (Sweden)

    Philipp S. Duncker

    2012-12-01

    Full Text Available The choice between different forest management practices is a crucial step in short, medium, and long-term decision making in forestry and when setting up measures to support a regional or national forest policy. Some conditions such as biogeographically determined site factors, exposure to major disturbances, and societal demands are predetermined, whereas operational processes such as species selection, site preparation, planting, tending, or thinning can be altered by management. In principle, the concept of a forest management approach provides a framework for decision making, including a range of silvicultural operations that influence the development of a stand or group of trees over time. These operations vary among silvicultural systems and can be formulated as a set of basic principles. Consequently, forest management approaches are essentially defined by coherent sets of forest operation processes at a stand level. Five ideal forest management approaches (FMAs representing a gradient of management intensity are described using specific sets of basic principles that enable comparison across European forests. Each approach is illustrated by a regional European case study. The observed regional variations resulting from changing species composition, stand density, age structure, stand edges, and site conditions can be interpreted using the FMA framework. Despite being arranged along an intensity gradient, the forest management approaches are not considered to be mutually exclusive, as the range of options allows for greater freedom in selecting potential silvicultural operations. As derived goods and services are clearly affected, the five forest management approaches have implications for sustainability. Thus, management objectives can influence the balance between the economic, ecological, and social dimensions of sustainability. The utility of this framework is further demonstrated through the different contributions to this special

  14. Tree migration detection through comparisons of historic and current forest inventories

    Science.gov (United States)

    Christopher W. Woodall; Christopher M. Oswalt; James A. Westfall; Charles H. Perry; Mark N. Nelson

    2009-01-01

    Changes in tree species distributions are a potential impact of climate change on forest ecosystems. The examination of tree species shifts in forests of the eastern United States largely has been limited to modeling activities with little empirical analysis of long-term forest inventory datasets. The goal of this study was to compare historic and current spatial...

  15. An empirical, hierarchical typology of tree species assemblages for assessing forest dynamics under global change scenarios

    Science.gov (United States)

    Jennifer K. Costanza; John W. Coulston; David N. Wear

    2017-01-01

    The composition of tree species occurring in a forest is important and can be affected by global change drivers such as climate change. To inform assessment and projection of global change impacts at broad extents, we used hierarchical cluster analysis and over 120,000 recent forest inventory plots to empirically define forest tree assemblages across the U.S., and...

  16. Survivorship of raked and unraked trees through prescribed fires in conifer forests in northeastern California

    Science.gov (United States)

    William F. Laudenslayer; George N. Steger; Jonathan. Arnold

    2008-01-01

    Large diameter, old trees are an important component of functioning forests, as they provide habitat for many wildlife species and add value to the scenery along roads and trails that cross our National Forests and Parks. Tree mortality, from prescribed or wild fire, is of great concern to forests managers, especially mortality of those of large diameter. Raking away...

  17. Pedoturbation by tree uprooting: the key pattern-forming factor in the forest soil

    Science.gov (United States)

    Bobrovsky, Maxim; Loyko, Sergey

    2017-04-01

    Treefalls with uprooting are the most powerful and ubiquitous biotic factor changing the structure of forest soil under free forest development. Practically every soil profile in a forest has a number of soil horizons anomalies which are located within the limits of the potential depth of treefall-related pedoturbations and these anomalies are indeed a result of treefalls in most cases. It is important to recognize signs of treefalls with uprooting in a soil profile even when signs of treefalls on the ground surface (pit-and-mound topography) are erased. Numerous field studies of forest soil in the European part of Russia and in the Western Siberia allowed us to generalize signs of treefalls in a soil profile, which can be used to distinguish the patterns of old treefall-related pedoturbations. We distinguish two main types of uprooting of a fallen tree: hinge and rotational tree uprooting (treefall). The signs of treefalls with uprooting in a soil profile are as follows: (1) treefall pits (cauldrons); (2) spotty or streaky structures of different degrees of contrast; (3) blocks of "buried material" from the upper soil layers; (4) washed (bleached) material depositing at the bottom of pits and filling soil pores and channels of various origins; (5) signs of hydrogenous changes of soil material resulting from water stagnation in the pits; (6) root channels at the bottom of the pit and (7) inclusions of litter and charcoal. We cleared that treefall-related pedoturbations affect soil profiles at a depth larger than the depth usually described by the soil horizons A, E, Bhs, etc. Therefore in most forest soils, the middle and lower parts of the profiles have patterns originating from the transfer of soil material upon treefalls. Age since the tree uprooting can be determined by dating of organic matter or charcoal located in old pits. We dated several tens of old tree uprooting pits by charcoal in sandy soil in the center and the east of the Russian Plain: they showed

  18. Height-diameter allometry of tropical forest trees

    Directory of Open Access Journals (Sweden)

    T. R. Feldpausch

    2011-05-01

    Full Text Available Tropical tree height-diameter (H:D relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical countries. Utilising this database, our objectives were:

    1. to determine if H:D relationships differ by geographic region and forest type (wet to dry forests, including zones of tension where forest and savanna overlap.

    2. to ascertain if the H:D relationship is modulated by climate and/or forest structural characteristics (e.g. stand-level basal area, A.

    3. to develop H:D allometric equations and evaluate biases to reduce error in future local-to-global estimates of tropical forest biomass.

    Annual precipitation coefficient of variation (PV, dry season length (SD, and mean annual air temperature (TA emerged as key drivers of variation in H:D relationships at the pantropical and region scales. Vegetation structure also played a role with trees in forests of a high A being, on average, taller at any given D. After the effects of environment and forest structure are taken into account, two main regional groups can be identified. Forests in Asia, Africa and the Guyana Shield all have, on average, similar H:D relationships, but with trees in the forests of much of the Amazon Basin and tropical Australia typically being shorter at any given D than their counterparts elsewhere. The region-environment-structure model with the lowest Akaike's information criterion and lowest deviation estimated stand-level H across all plots to within amedian −2.7 to 0.9% of the true value. Some of the plot-to-plot variability in

  19. Physical attributes of some clouds amid a forest ecosystem's trees

    Science.gov (United States)

    DeFelice, Thomas P.

    2002-01-01

    Cloud or fog water collected by forest canopies of any elevation could represent significant sources of required moisture and nutrients for forest ecosystems, human consumption, and as an alternative source of water for agriculture and domestic use. The physical characteristics of fogs and other clouds have been well studied, and this information can be useful to water balance or canopy–cloud interaction model verification and to calibration or training of satellite-borne sensors to recognize atmospheric attributes, such as optical thickness, albedo, and cloud properties. These studies have taken place above-canopy or within canopy clearings and rarely amid the canopy. Simultaneous physical and chemical characteristics of clouds amid and above the trees of a mountain forest, located about 3.3 km southwest of Mt. Mitchell, NC, were collected between 13 and 22 June 1993. This paper summarizes the physical characteristics of the cloud portions amid the trees. The characteristic cloud amid the trees (including cloud and precipitation periods) contained 250 droplet/cm3 with a mean diameter of 9.5 μm and liquid water content (LWC) of 0.11 g m−3. The cloud droplets exhibited a bimodal distribution with modes at about 2 and 8 μm and a mean diameter near 5 μm during precipitation-free periods, whereas the concurrent above-canopy cloud droplets had a unimodal distribution with a mode near 6 μm and a mean diameter of 6 μm. The horizontal cloud water flux is nonlinearly related to the rate of collection onto that surface amid the trees, especially for the Atmospheric Sciences Research Center (ASRC) sampling device, whereas it is linear when the forward scattering spectrometer probe (FSSP) are is used. These findings suggest that statements about the effects clouds have on surfaces they encounter, which are based on above-canopy or canopy-clearing data, can be misleading, if not erroneous.

  20. Air pollution effects on forest trees and forest soils. Wirkungen von Luftverunreinigungen auf Waldbaeume und Waldboeden

    Energy Technology Data Exchange (ETDEWEB)

    Fuehr, F.; Ganser, S.; Kloster, G.; Prinz, B.; Stuettgen, E. (comps.)

    1986-08-01

    From December 2-4, 1985 the 'Project Management for Ecotoxicological Research' in the Nuclear Research Centre, Juelich (PTU) and the 'Landesanstalt fuer Immissionsschutz' des Landes Nordrhein-Westfalen (LIS) organized a joint seminar concerning the topics a) effects of air pollutions on above parts of forest trees (LIS), b) effects of air pollutions on soil and below parts of forest trees (PTU). The presentations to topic a) were focused on air pollutants as possible factors for direct damage of above parts of forest trees. In order to answer this question both morphological, cytological and physiological aspects were considered. Topic b) emphasized investigations concerning changes of soil conditions by depositions of pollutants, nitrogen impact and the effects on forest ecosystems as well as turnover of fine roots and the importance/function of mycorrhiza within the ecosystem forest/soil. The report contains the presentations and results of the mentioned topics. Separate records are available for all 71 papers of these proceedings as well as for the 3 summary reviews of the conference papers.

  1. Some forest trees for honeydew honey production in Turkey

    Directory of Open Access Journals (Sweden)

    S. Ünal

    2017-08-01

    Full Text Available Honey is an important source of nutrients and energy and an effective remedy against various human diseases. Honeydew honey is produced from honeydew of phloem-feeders that honeybees gather. In this study, we focused on honeydew producers and diversity of host tree species which are involved in honeydew production in Turkey. A total of 24 honeydew producers by host tree species are identified in Turkey. Of these, 13 coniferous trees and 11 deciduous trees. The main honeydew producer in Turkey is a scale insect, Marchalina hellenica Gennadius (Hemiptera: Margarodidae living mainly on pines (Turkish red pine, Aleppo pine, and rarely on stone pine, Anatolian black pine and Scots pine. Honeydew producer insects can be treated as serious pests of conifer and broadleaf trees. The aphids and the scale insects such as Ceroplastes floridensis, Cinara cedri, C. laportei, Eulachnus rileyi, Icerya purchase, Kermes vermilio, Lichtensia viburni and Saissetia oleae are known as pests in several European, Asian and African countries. Despite their potential harm to their host plants, insect species producing honeydew play an important role in honey production in Turkey. Turkish honey production is exported to EU countries and, furthermore beekeeping is an important part of agricultural sector in Turkey.

  2. Tree height integrated into pantropical forest biomass estimates

    Directory of Open Access Journals (Sweden)

    T. R. Feldpausch

    2012-08-01

    Full Text Available Aboveground tropical tree biomass and carbon storage estimates commonly ignore tree height (H. We estimate the effect of incorporating H on tropics-wide forest biomass estimates in 327 plots across four continents using 42 656 H and diameter measurements and harvested trees from 20 sites to answer the following questions:

    1. What is the best H-model form and geographic unit to include in biomass models to minimise site-level uncertainty in estimates of destructive biomass?

    2. To what extent does including H estimates derived in (1 reduce uncertainty in biomass estimates across all 327 plots?

    3. What effect does accounting for H have on plot- and continental-scale forest biomass estimates?

    The mean relative error in biomass estimates of destructively harvested trees when including H (mean 0.06, was half that when excluding H (mean 0.13. Power- and Weibull-H models provided the greatest reduction in uncertainty, with regional Weibull-H models preferred because they reduce uncertainty in smaller-diameter classes (≤40 cm D that store about one-third of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows that including H reduces errors from 41.8 Mg ha−1 (range 6.6 to 112.4 to 8.0 Mg ha−1 (−2.5 to 23.0. For all plots, aboveground live biomass was −52.2 Mg ha−1 (−82.0 to −20.3 bootstrapped 95% CI, or 13%, lower when including H estimates, with the greatest relative reductions in estimated biomass in forests of the Brazilian Shield, east Africa, and Australia, and relatively little change in the Guiana Shield, central Africa and southeast Asia. Appreciably different stand structure was observed among regions across the tropical continents, with some storing significantly

  3. Ever-young sex chromosomes in European tree frogs.

    Science.gov (United States)

    Stöck, Matthias; Horn, Agnès; Grossen, Christine; Lindtke, Dorothea; Sermier, Roberto; Betto-Colliard, Caroline; Dufresnes, Christophe; Bonjour, Emmanuel; Dumas, Zoé; Luquet, Emilien; Maddalena, Tiziano; Sousa, Helena Clavero; Martinez-Solano, Iñigo; Perrin, Nicolas

    2011-05-01

    Non-recombining sex chromosomes are expected to undergo evolutionary decay, ending up genetically degenerated, as has happened in birds and mammals. Why are then sex chromosomes so often homomorphic in cold-blooded vertebrates? One possible explanation is a high rate of turnover events, replacing master sex-determining genes by new ones on other chromosomes. An alternative is that X-Y similarity is maintained by occasional recombination events, occurring in sex-reversed XY females. Based on mitochondrial and nuclear gene sequences, we estimated the divergence times between European tree frogs (Hyla arborea, H. intermedia, and H. molleri) to the upper Miocene, about 5.4-7.1 million years ago. Sibship analyses of microsatellite polymorphisms revealed that all three species have the same pair of sex chromosomes, with complete absence of X-Y recombination in males. Despite this, sequences of sex-linked loci show no divergence between the X and Y chromosomes. In the phylogeny, the X and Y alleles cluster according to species, not in groups of gametologs. We conclude that sex-chromosome homomorphy in these tree frogs does not result from a recent turnover but is maintained over evolutionary timescales by occasional X-Y recombination. Seemingly young sex chromosomes may thus carry old-established sex-determining genes, a result at odds with the view that sex chromosomes necessarily decay until they are replaced. This raises intriguing perspectives regarding the evolutionary dynamics of sexually antagonistic genes and the mechanisms that control X-Y recombination.

  4. The effects of habitat degradation on metacommunity structure of wood-inhabiting fungi in European beech forests

    DEFF Research Database (Denmark)

    Halme, Panu; Ódor, Péter; Christensen, Morten

    2013-01-01

    with different management histories. For this purpose, we used a large data set of wood-inhabiting fungi collected from dead beech trees in European beech-dominated forest reserves. The structure of fungal assemblages showed high beta diversity, while nestedness and similarity was low. During the decomposition...... extirpated specialized species from the local species pools in managed sites, and resulted in more homogeneous communities in managed sites. It is alarming that community structure is affected the most in the latest decay stages where the decay process turns the dead wood into litter, and which is thus......Intensive forest management creates habitat degradation by reducing the variation of forest stands in general, and by removing old trees and dead wood in particular. Non-intervention forest reserves are commonly believed to be the most efficient tool to counteract the negative effects...

  5. The contribution of trees outside forests to national tree biomass and carbon stocks--a comparative study across three continents.

    Science.gov (United States)

    Schnell, Sebastian; Altrell, Dan; Ståhl, Göran; Kleinn, Christoph

    2015-01-01

    In contrast to forest trees, trees outside forests (TOF) often are not included in the national monitoring of tree resources. Consequently, data about this particular resource is rare, and available information is typically fragmented across the different institutions and stakeholders that deal with one or more of the various TOF types. Thus, even if information is available, it is difficult to aggregate data into overall national statistics. However, the National Forest Monitoring and Assessment (NFMA) programme of FAO offers a unique possibility to study TOF resources because TOF are integrated by default into the NFMA inventory design. We have analysed NFMA data from 11 countries across three continents. For six countries, we found that more than 10% of the national above-ground tree biomass was actually accumulated outside forests. The highest value (73%) was observed for Bangladesh (total forest cover 8.1%, average biomass per hectare in forest 33.4 t ha(-1)) and the lowest (3%) was observed for Zambia (total forest cover 63.9%, average biomass per hectare in forest 32 t ha(-1)). Average TOF biomass stocks were estimated to be smaller than 10 t ha(-1). However, given the large extent of non-forest areas, these stocks sum up to considerable quantities in many countries. There are good reasons to overcome sectoral boundaries and to extend national forest monitoring programmes on a more systematic basis that includes TOF. Such an approach, for example, would generate a more complete picture of the national tree biomass. In the context of climate change mitigation and adaptation, international climate mitigation programmes (e.g. Clean Development Mechanism and Reduced Emission from Deforestation and Degradation) focus on forest trees without considering the impact of TOF, a consideration this study finds crucial if accurate measurements of national tree biomass and carbon pools are required.

  6. Photo guide for estimating risk to hardwood trees during prescribed burning operations in eastern oak forests

    Science.gov (United States)

    Patrick H. Brose

    2009-01-01

    A field guide of 40 photographs of common hardwood trees of eastern oak forests and fuel loadings surrounding their bases. The guide contains instructions on how to rapidly assess a tree's likelihood to be damaged or killed by prescribed burning.

  7. Whole tree xylem sap flow responses to multiple environmental variables in a wet tropical forest

    Science.gov (United States)

    J.J. O' Brien; S.F. Oberbauer; D.B. Clark

    2004-01-01

    In order to quantify and characterize the variance in rain-forest tree physiology, whole tree sap flow responses to local environmental conditions were investigated in 10 species of trees with diverse traits at La Selva Biological Station, Costa Rica. A simple model was developed to predict tree sap flow responses to a synthetic environmental variable generated by a...

  8. Below- and above-ground tree species diversity in natural forest and ...

    African Journals Online (AJOL)

    The conversion of natural forests to monoculture tree plantations (MTPs) has been known to reduce above-ground tree diversity. However, information is lacking on the impact of MTPs on below-ground tree species diversity. This study evaluated below- and above-ground tree species diversity in a Strict Nature Reserve ...

  9. Applications of ion chromatography to study pollution effects on forest trees

    Science.gov (United States)

    Walter C. Shortle; Rakesh Minocha

    1990-01-01

    Air pollution and acidic deposition can influence forest tree growth and survival by causing ionic imbalances in the rooting zone. Altered nutrient status suppresses tree growth and weakens its immune system. Internal infections spread more quickly in response to weakened tree defenses. As adverse conditions persist, many trees die and the survivors are less healthy....

  10. Tree communities of white-sand and terra-firme forests of the upper Rio Negro

    NARCIS (Netherlands)

    Stropp, J.; Sleen, van der J.P.; Assunção, P.A.; Silva, da A.L.; Steege, ter H.

    2011-01-01

    The high tree diversity and vast extent of Amazonian forests challenge our understanding of how tree species abundance and composition varies across this region. Information about these parameters, usually obtained from tree inventories plots, is essential for revealing patterns of tree diversity.

  11. Examination of forest products trade between Turkey and European ...

    African Journals Online (AJOL)

    The success of getting in the foreign trade forms one of the basic stones of economic development for countries. The current and potential trading volume among countries and determining the main factors affecting trade are quite important. The trade currents of the European Union (EU) countries and Turkey in the forest ...

  12. Forest resource projection tools at the European level

    NARCIS (Netherlands)

    Schelhaas, M.; Nabuurs, G.J.; Verkerk, P.J.; Hengeveld, G.M.; Packalen, Tuula; Sallnäs, O.; Pilli, Roberto; Grassi, J.; Forsell, Nicklas; Frank, S.; Gusti, Mykola; Havlik, Petr

    2017-01-01

    Many countries have developed their own systems for projecting forest resources and wood availability. Although studies using these tools are helpful for developing national policies, they do not provide a consistent assessment for larger regions such as the European Union or Europe as a whole.

  13. Methods and equations for estimating aboveground volume, biomass, and carbon for trees in the U.S. forest inventory, 2010

    Science.gov (United States)

    Christopher W. Woodall; Linda S. Heath; Grant M. Domke; Michael C. Nichols

    2011-01-01

    The U.S. Forest Service, Forest Inventory and Analysis (FIA) program uses numerous models and associated coefficients to estimate aboveground volume, biomass, and carbon for live and standing dead trees for most tree species in forests of the United States. The tree attribute models are coupled with FIA's national inventory of sampled trees to produce estimates of...

  14. Creating a Regional MODIS Satellite-Driven Net Primary Production Dataset for European Forests

    Directory of Open Access Journals (Sweden)

    Mathias Neumann

    2016-06-01

    Full Text Available Net primary production (NPP is an important ecological metric for studying forest ecosystems and their carbon sequestration, for assessing the potential supply of food or timber and quantifying the impacts of climate change on ecosystems. The global MODIS NPP dataset using the MOD17 algorithm provides valuable information for monitoring NPP at 1-km resolution. Since coarse-resolution global climate data are used, the global dataset may contain uncertainties for Europe. We used a 1-km daily gridded European climate data set with the MOD17 algorithm to create the regional NPP dataset MODIS EURO. For evaluation of this new dataset, we compare MODIS EURO with terrestrial driven NPP from analyzing and harmonizing forest inventory data (NFI from 196,434 plots in 12 European countries as well as the global MODIS NPP dataset for the years 2000 to 2012. Comparing these three NPP datasets, we found that the global MODIS NPP dataset differs from NFI NPP by 26%, while MODIS EURO only differs by 7%. MODIS EURO also agrees with NFI NPP across scales (from continental, regional to country and gradients (elevation, location, tree age, dominant species, etc.. The agreement is particularly good for elevation, dominant species or tree height. This suggests that using improved climate data allows the MOD17 algorithm to provide realistic NPP estimates for Europe. Local discrepancies between MODIS EURO and NFI NPP can be related to differences in stand density due to forest management and the national carbon estimation methods. With this study, we provide a consistent, temporally continuous and spatially explicit productivity dataset for the years 2000 to 2012 on a 1-km resolution, which can be used to assess climate change impacts on ecosystems or the potential biomass supply of the European forests for an increasing bio-based economy. MODIS EURO data are made freely available at ftp://palantir.boku.ac.at/Public/MODIS_EURO.

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

    Directory of Open Access Journals (Sweden)

    Alfredo eDi Filippo

    2015-05-01

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

  16. Remnant trees affect species composition but not structure of tropical second-growth forest.

    Science.gov (United States)

    Sandor, Manette E; Chazdon, Robin L

    2014-01-01

    Remnant trees, spared from cutting when tropical forests are cleared for agriculture or grazing, act as nuclei of forest regeneration following field abandonment. Previous studies on remnant trees were primarily conducted in active pasture or old fields abandoned in the previous 2-3 years, and focused on structure and species richness of regenerating forest, but not species composition. Our study is among the first to investigate the effects of remnant trees on neighborhood forest structure, biodiversity, and species composition 20 years post-abandonment. We compared the woody vegetation around individual remnant trees to nearby plots without remnant trees in the same second-growth forests ("control plots"). Forest structure beneath remnant trees did not differ significantly from control plots. Species richness and species diversity were significantly higher around remnant trees. The species composition around remnant trees differed significantly from control plots and more closely resembled the species composition of nearby old-growth forest. The proportion of old-growth specialists and generalists around remnant trees was significantly greater than in control plots. Although previous studies show that remnant trees may initially accelerate secondary forest growth, we found no evidence that they locally affect stem density, basal area, and seedling density at later stages of regrowth. Remnant trees do, however, have a clear effect on the species diversity, composition, and ecological groups of the surrounding woody vegetation, even after 20 years of forest regeneration. To accelerate the return of diversity and old-growth forest species into regrowing forest on abandoned land, landowners should be encouraged to retain remnant trees in agricultural or pastoral fields.

  17. Unlocking the forest inventory data: relating individual tree performance to unmeasured environmental factors

    Science.gov (United States)

    Jeremy W. Lichstein; Jonathan Dushoff; Kiona Ogle; Anping Chen; Drew W. Purves; John P. Caspersen; Stephen W. Pacala

    2010-01-01

    Geographically extensive forest inventories, such as the USDA Forest Service's Forest Inventory and Analysis (FIA) program, contain millions of individual tree growth and mortality records that could be used to develop broad-scale models of forest dynamics. A limitation of inventory data, however, is that individual-level measurements of light (L) and other...

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

    Science.gov (United States)

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

    2017-01-01

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

  19. Phylogenetic Structure of Tree Species across Different Life Stages from Seedlings to Canopy Trees in a Subtropical Evergreen Broad-Leaved Forest.

    Science.gov (United States)

    Jin, Yi; Qian, Hong; Yu, Mingjian

    2015-01-01

    Investigating patterns of phylogenetic structure across different life stages of tree species in forests is crucial to understanding forest community assembly, and investigating forest gap influence on the phylogenetic structure of forest regeneration is necessary for understanding forest community assembly. Here, we examine the phylogenetic structure of tree species across life stages from seedlings to canopy trees, as well as forest gap influence on the phylogenetic structure of forest regeneration in a forest of the subtropical region in China. We investigate changes in phylogenetic relatedness (measured as NRI) of tree species from seedlings, saplings, treelets to canopy trees; we compare the phylogenetic turnover (measured as βNRI) between canopy trees and seedlings in forest understory with that between canopy trees and seedlings in forest gaps. We found that phylogenetic relatedness generally increases from seedlings through saplings and treelets up to canopy trees, and that phylogenetic relatedness does not differ between seedlings in forest understory and those in forest gaps, but phylogenetic turnover between canopy trees and seedlings in forest understory is lower than that between canopy trees and seedlings in forest gaps. We conclude that tree species tend to be more closely related from seedling to canopy layers, and that forest gaps alter the seedling phylogenetic turnover of the studied forest. It is likely that the increasing trend of phylogenetic clustering as tree stem size increases observed in this subtropical forest is primarily driven by abiotic filtering processes, which select a set of closely related evergreen broad-leaved tree species whose regeneration has adapted to the closed canopy environments of the subtropical forest developed under the regional monsoon climate.

  20. Is there a positive relationship between naturalness and genetic diversity in forest tree communities?

    Energy Technology Data Exchange (ETDEWEB)

    Wehenkel, C.; Corral-Rivas, J. J.; Castellanos-Bocaz, H. A.; Pinedo-Alvarez, A.

    2009-07-01

    Abstract The concepts of genetic diversity and naturalness are well known as measures of conservation values and as descriptors of state or condition. A lack of research evaluating the relationship between genetic diversity and naturalness in biological communities, along with the possible implications in terms of evolutionary aspects and conservation management, make this subject particularly important as regards forest tree communities.We therefore examined the following hypothesis: the genetic diversity of a central-European tree stand averaged over species increases with the naturalness of the stand, as defined by the Potential Natural Vegetation (PNV). The results obtained show that the hypothesis is unsustainable because differences between the averaged genetic diversities of the unnatural and semi-natural stand classes (69 cases) were mostly non-significant. Moreover in three cases, the average genetic diversity of unnatural stand classes was significantly higher than the average genetic diversity of the semi-natural stand classes. A significantly lower average genetic diversity of unnatural stand class was not detected in the statistical analysis. Thus, the naturalness of a tree species community, as inferred from PNV, does not serve as a straightforward indicator of ecological stability when the genetic diversity and the adaptability of tree species are unknown. (Author) 30 refs.

  1. Effects of European land use on contemporary tree-climate relationships in the northeastern United States: Implications for predictive models

    Science.gov (United States)

    Goring, S. J.; Cogbill, C. V.; Dawson, A.; Hooten, M.; McLachlan, J. S.; Mladenoff, D. J.; Paciorek, C. J.; Ruid, M.; Tipton, J.; Williams, J. W.; Record, S.; Matthes, J. H.; Dietze, M.

    2014-12-01

    Much of our understanding of the climatic controls on tree species distributions is based on contemporary observational datasets. For example, forest inventory analysis (FIA) and other spatial datasets are used to build correlative models of climate suitability for plant taxa for use in environmental niche models. More complex dynamic models rely on species interactions, physiological processes, and competition, among other processes, that are also parameterized against contemporary data. However, as much as a quarter of the forested region in the upper Midwestern United States may be considered novel relative to pre-settlement baselines (Goring et al. submitted). Hence, modern surveys or even long-term datasets may represent only a portion of the ecological or climate space taxa might occupy. Using gridded datasets of pre-settlement vegetation for the northeastern United States from Town Propritor Suveys and the Public Land Survey, we examine the effects of European land-use conversion - logging, agricultural conversion and re-establishment - on climate-vegetation relationships. We show that in regions where land-use change is climatically biased, such as conversion to agriculture along the prairie-forest boundary, impacts on the realized climatic niches for various tree taxa can be significant. Improving predicted distributions of taxa is critical for planning and mitigating the effects of widespread shifts in forest composition resulting from climate change. Using pre-settlement data can improve our understanding of the potential niches occupied by major forest taxa, improving the predictive abilities of environmental niche and mechanistic models.

  2. Planting sentinel European trees in eastern Asia as a novel method to identify potential insect pest invaders.

    Science.gov (United States)

    Roques, Alain; Fan, Jian-Ting; Courtial, Béatrice; Zhang, Yan-Zhuo; Yart, Annie; Auger-Rozenberg, Marie-Anne; Denux, Olivier; Kenis, Marc; Baker, Richard; Sun, Jiang-Hua

    2015-01-01

    Quarantine measures to prevent insect invasions tend to focus on well-known pests but a large proportion of the recent invaders were not known to cause significant damage in their native range, or were not even known to science before their introduction. A novel method is proposed to detect new potential pests of woody plants in their region of origin before they are introduced to a new continent. Since Asia is currently considered to be the main supplier of insect invaders to Europe, sentinel trees were planted in China during 2007-2011 as an early warning tool to identify the potential for additional Asian insect species to colonize European trees. Seedlings (1-1.5 m tall) of five broadleaved (Quercus petraea, Q. suber, Q. ilex, Fagus sylvatica, and Carpinus betulus) and two conifer species (Abies alba and Cupressus sempervirens) were planted in blocks of 100 seedlings at two widely separated sites (one in a nursery near Beijing and the other in a forest environment near Fuyang in eastern China), and then regularly surveyed for colonization by insects. A total of 104 insect species, mostly defoliators, were observed on these new hosts, and at least six species were capable of larval development. Although a number of the insects observed were probably incidental feeders, 38 species had more than five colonization events, mostly infesting Q. petraea, and could be considered as being capable of switching to European trees if introduced to Europe. Three years was shown to be an appropriate duration for the experiment, since the rate of colonization then tended to plateau. A majority of the identified species appeared to have switched from agricultural crops and fruit trees rather than from forest trees. Although these results are promising, the method is not appropriate for xylophagous pests and other groups developing on larger trees. Apart from the logistical problems, the identification to species level of the specimens collected was a major difficulty. This

  3. Ever-young sex chromosomes in European tree frogs.

    Directory of Open Access Journals (Sweden)

    Matthias Stöck

    2011-05-01

    Full Text Available Non-recombining sex chromosomes are expected to undergo evolutionary decay, ending up genetically degenerated, as has happened in birds and mammals. Why are then sex chromosomes so often homomorphic in cold-blooded vertebrates? One possible explanation is a high rate of turnover events, replacing master sex-determining genes by new ones on other chromosomes. An alternative is that X-Y similarity is maintained by occasional recombination events, occurring in sex-reversed XY females. Based on mitochondrial and nuclear gene sequences, we estimated the divergence times between European tree frogs (Hyla arborea, H. intermedia, and H. molleri to the upper Miocene, about 5.4-7.1 million years ago. Sibship analyses of microsatellite polymorphisms revealed that all three species have the same pair of sex chromosomes, with complete absence of X-Y recombination in males. Despite this, sequences of sex-linked loci show no divergence between the X and Y chromosomes. In the phylogeny, the X and Y alleles cluster according to species, not in groups of gametologs. We conclude that sex-chromosome homomorphy in these tree frogs does not result from a recent turnover but is maintained over evolutionary timescales by occasional X-Y recombination. Seemingly young sex chromosomes may thus carry old-established sex-determining genes, a result at odds with the view that sex chromosomes necessarily decay until they are replaced. This raises intriguing perspectives regarding the evolutionary dynamics of sexually antagonistic genes and the mechanisms that control X-Y recombination.

  4. Tree- and Stand-Level Thinning Effects on Growth of European Beech (Fagus sylvatica L. on a Northeast- and a Southwest-Facing Slope in Southwest Germany

    Directory of Open Access Journals (Sweden)

    Daniela Diaconu

    2015-09-01

    Full Text Available Anticipated changes in climate and research findings on the drought sensitivity of beech have triggered controversial discussions about the future of European beech. We investigated the growth response of beech on the tree- and stand-level in mature stands to three different thinning intensities (no thinning, strong thinning, very strong thinning on a northeast- and southwest-facing slope in Southwest Germany. Linear mixed-effects models were formulated to describe effects on growth parameters on the tree- and stand-level (diameter, height, basal area, volume. At the stand-level, the stand basal area increment and stand volume increment were lower on the thinned plots. At the tree-level, the basal area increment significantly increased with increasing thinning intensity. The growth of individual trees was also influenced by initial tree size, the size-related rank of the tree within a stand, and by the aspect of the site. Our data indicate that growth of European beech is impaired on the southwest-facing slope with a warmer and drier climate and that a very strong thinning regime applied at advanced age can accelerate growth of European beech trees even on the warmer and drier site. Our findings, therefore, imply that in a warmer climate intensive thinning may also represent an important adaptive forest management measure in European beech stands.

  5. Nitrous oxide fluxes from tree stems in temperate forest ecosystems

    Science.gov (United States)

    Wen, Y.; Corre, M. D.; Veldkamp, E.

    2016-12-01

    Investigations on tree-mediated N2O fluxes are rare and restricted mostly to seedlings and saplings. Presently, little is known about N2O fluxes from mature trees in field conditions as well as their contributions to total forest N2O fluxes. Here we quantified in situ stem N2O fluxes from mature alder trees on poorly-drained soil and mature beech and spruce trees on well-drained soil in Solling, Germany from March to October 2015. Soil N2O fluxes, soil N2O concentrations in 40-cm depth and other environmental factors were also measured simultaneously. In the present study, alder, beech and spruce consistently emitted N2O via stems and all displayed higher emission rates in summer than in spring and autumn. Stem N2O fluxes increased with increasing air and soil temperature, suggesting the influence of temperature on soil N2O production and soil-plant N2O transport (via transpiration stream). Increased in vapor pressure deficit speeded up stem N2O fluxes in alder and spruce, possibly because of enhanced sap flow rates and the subsequent dissolved N2O transport rates. In the alder stand, the significant correlations between stem N2O fluxes, soil N2O fluxes and soil N2O concentrations suggest that N2O transport may have been facilitated by a combination of passive diffusion and convective mechanisms. In the beech and spruce stands, the significant correlations between stem N2O fluxes, temperature and vapor pressure deficit suggest convective transport of soil N2O to the stem. Overall, stem N2O fluxes from alder were higher than beech and spruce due to the presence of aerenchyma and lenticels as well as higher soil water content and soil N availability in the alder stand. Stem N2O fluxes represented 8-11% of the total N2O fluxes in the spruce and beech stands, whereas in the alder stand with large soil N2O fluxes its stem emissions contributed only 1% to total N2O fluxes. Our study provided information of hitherto unknown tree-mediated N2O contribution to forest N2O

  6. Tree diversity in the tropical dry forest of Bannerghatta National Park in Eastern Ghats, Southern India

    Directory of Open Access Journals (Sweden)

    Gopalakrishna S. Puttakame

    2015-12-01

    Full Text Available Tree species inventories, particularly of poorly known dry deciduous forests, are needed to protect and restore forests in degraded landscapes. A study of forest stand structure, and species diversity and density of trees with girth at breast height (GBH ≥10 cm was conducted in four management zones of Bannerghatta National Park (BNP in the Eastern Ghats of Southern India. We identified 128 tree species belonging to 45 families in 7.9 hectares. However, 44 species were represented by ≤ 2 individuals. Mean diversity values per site for the dry forest of BNP were: tree composition (23.8 ±7.6, plant density (100.69 ± 40.02, species diversity (2.56 ± 0.44 and species richness (10.48 ± 4.05. Tree diversity was not significantly different (P>0.05 across the four management zones in the park. However, the number of tree species identified significantly (P<0.05 increased with increasing number of sampling sites, but majority of the species were captured. Similarly, there were significant variations (p<0.05 between tree diameter class distributions. Juveniles accounted for 87% of the tree population. The structure of the forest was not homogeneous, with sections ranging from poorly structured to highly stratified configurations. The study suggests that there was moderate tree diversity in the tropical dry thorn forest of Bannerghatta National Park, but the forest was relatively young.

  7. Disentangling above- and below-ground competition between lianas and trees in a tropical forest

    NARCIS (Netherlands)

    Schnitzer, S.A.; Kuzee, M.E.; Bongers, F.J.J.M.

    2005-01-01

    1 Light is thought to be the most limiting resource in tropical forests, and thus aboveground competition is commonly accepted as the mechanism that structures these communities. In many tropical forests, trees compete not only with other trees, but also with lianas, which compete aggressively for

  8. Gene-assisted selection: applications of association genetics for forest tree breeding

    Science.gov (United States)

    Philip L. Wilcox; Craig E. Echt; Rowland D. Burdon

    2007-01-01

    This chapter describes application of association genetics in forest tree species for the purposes of selection. We use the term gene-assisted selection (GAS) to denote application of marker-trait associations determined via association genetics, which we anticipate will be based on poly morph isms associated with expressed genes. The salient features of forest trees...

  9. Does the Transfer of Forest Reproductive Material Significantly Affect Local Tree Diversity?

    NARCIS (Netherlands)

    Kramer, K.; Geburek, Thomas; Jansen, Simon

    2016-01-01

    Genetic variation within tree species is an important component
    of forest biodiversity. It enables forest ecosystems to adapt to
    environmental changes and it provides genetic material for
    breeding to sustainably increase production. In the framework of
    forestry activities, tree

  10. Drought, tree mortality, and wildfire in forests adapted to frequent fire

    Science.gov (United States)

    Scott L Stephens; Brandon M Collins; Christopher J Fettig; Mark A Finney; Chad M Hoffman; Eric E Knapp; Malcolm P North; Hugh Safford; Rebecca B Wayman

    2018-01-01

    Massive tree mortality has occurred rapidly in frequent-fire-adapted forests of the Sierra Nevada, California. This mortality is a product of acute drought compounded by the long-established removal of a key ecosystem process: frequent, low- to moderate-intensity fire. The recent tree mortality has many implications for the future of these forests and the ecological...

  11. Somatic embryogenesis and cryostorage for conservation and restoration of threatened forest trees

    Science.gov (United States)

    S.A. Merkle; A.R. Tull; H.J. Gladfelter; P.M. Montello; J.E. Mitchell; C. Ahn; R.D. McNeill

    2017-01-01

    Threats to North American forest trees from exotic pests and pathogens or habitat loss, make it imperative that every available tool be employed for conservation and restoration of these at risk species. One such tool, in vitro propagation, could greatly enhance conservation of forest tree genetic material and selection and breeding of resistant or...

  12. Silviculture and the assessment of climate change genetic risk for southern Appalachian forest tree species

    Science.gov (United States)

    Kevin M. Potter; Barbara S. Crane

    2012-01-01

    Changing climate conditions and increasing insect and pathogen infestations will increase the likelihood that forest trees could experience population-level extirpation or species-level extinction during the next century. Gene conservation and silvicultural efforts to preserve forest tree genetic diversity present a particular challenge in species-rich regions such as...

  13. Assisted migration of forest populations for adapting trees to climate change

    Science.gov (United States)

    Cuauhtémoc Sáenz-Romero; Roberto A. Lindig-Cisneros; Dennis G. Joyce; Jean Beaulieu; J. Bradley St. Clair; Barry C. Jaquish

    2016-01-01

    We present evidence that climatic change is an ongoing process and that forest tree populations are genetically differentiated for quantitative traits because of adaptation to specific habitats. We discuss in detail indications that the shift of suitable climatic habitat for forest tree species and populations, as a result of rapid climatic change, is likely to cause...

  14. Earthworm abundance and species composition in abandoned tropical croplands: comparisons of tree plantations and secondary forests.

    Science.gov (United States)

    G. Gonzalez; X. Zou; S. Borges

    1996-01-01

    We compared patterns of earthworms abundance and species composition in tree plantation and secondary forest of Puerto Rico. Tree plantations included pine (Pinus caribea Morelet) and mahogany (Swietenia macrophylla King) established in the 1930's; 1960's; and 1970's; secondary forests were naturally regenerated in areas adjacent to these plantations. We...

  15. Reconstructing European forest management from 1600 to 2010

    Science.gov (United States)

    McGrath, M. J.; Luyssaert, S.; Meyfroidt, P.; Kaplan, J. O.; Bürgi, M.; Chen, Y.; Erb, K.; Gimmi, U.; McInerney, D.; Naudts, K.; Otto, J.; Pasztor, F.; Ryder, J.; Schelhaas, M.-J.; Valade, A.

    2015-07-01

    Because of the slow accumulation and long residence time of carbon in biomass and soils, the present state and future dynamics of temperate forests are influenced by management that took place centuries to millennia ago. Humans have exploited the forests of Europe for fuel, construction materials and fodder for the entire Holocene. In recent centuries, economic and demographic trends led to increases in both forest area and management intensity across much of Europe. In order to quantify the effects of these changes in forests and to provide a baseline for studies on future land-cover-climate interactions and biogeochemical cycling, we created a temporally and spatially resolved reconstruction of European forest management from 1600 to 2010. For the period 1600-1828, we took a supply-demand approach, in which supply was estimated on the basis of historical annual wood increment and land cover reconstructions. We made demand estimates by multiplying population with consumption factors for construction materials, household fuelwood, industrial food processing and brewing, metallurgy, and salt production. For the period 1829-2010, we used a supply-driven backcasting method based on national and regional statistics of forest age structure from the second half of the 20th century. Our reconstruction reproduces the most important changes in forest management between 1600 and 2010: (1) an increase of 593 000 km2 in conifers at the expense of deciduous forest (decreasing by 538 000 km2); (2) a 612 000 km2 decrease in unmanaged forest; (3) a 152 000 km2 decrease in coppice management; (4) a 818 000 km2 increase in high-stand management; and (5) the rise and fall of litter raking, which at its peak in 1853 resulted in the removal of 50 Tg dry litter per year.

  16. Insect-induced tree mortality of boreal forests in eastern Canada under a changing climate.

    Science.gov (United States)

    Zhang, Xiongqing; Lei, Yuancai; Ma, Zhihai; Kneeshaw, Dan; Peng, Changhui

    2014-06-01

    Forest insects are major disturbances that induce tree mortality in eastern coniferous (or fir-spruce) forests in eastern North America. The spruce budworm (SBW) (Choristoneura fumiferana [Clemens]) is the most devastating insect causing tree mortality. However, the relative importance of insect-caused mortality versus tree mortality caused by other agents and how this relationship will change with climate change is not known. Based on permanent sample plots across eastern Canada, we combined a logistic model with a negative model to estimate tree mortality. The results showed that tree mortality increased mainly due to forest insects. The mean difference in annual tree mortality between plots disturbed by insects and those without insect disturbance was 0.0680 per year (P forests. We also found that annual tree mortality increased significantly with the annual climate moisture index (CMI) and decreased significantly with annual minimum temperature (T min), annual mean temperature (T mean) and the number of degree days below 0°C (DD0), which was inconsistent with previous studies (Adams et al. 2009; van Mantgem et al. 2009; Allen et al. 2010). Furthermore, the results for the trends in the magnitude of forest insect outbreaks were consistent with those of climate factors for annual tree mortality. Our results demonstrate that forest insects are the dominant cause of the tree mortality in eastern Canada but that tree mortality induced by insect outbreaks will decrease in eastern Canada under warming climate.

  17. Aboveground biomass, wood volume, nutrient stocks and leaf litter in novel forests compared to native forests and tree plantations in Puerto Rico

    Science.gov (United States)

    A.E. Lugo; O. Abelleira Martínez; J. Fonseca da Silva

    2012-01-01

    The article presents comparative data for aboveground biomass, wood volume, nutirent stocks (N, P, K) and leaf litter in different types of forests in Puerto Rico. The aim of the study is to assess how novel forests of Castilla elastica, Panama Rubber Tree, and Spathodea campanulata, African Tulip Tree, compare with tree plantations and native historical forests (both...

  18. Gurjun-Oil Tree: Buddhist Way and the Conservation and Revitalization of Gurjun-Oil Trees in Isan Cultural Forests

    OpenAIRE

    Chatchawan Kaewsaen; Katharat Hengtragoon; Terdchai Pantachi

    2010-01-01

    Problem statement: This research aimed at investigating the background of gurjun-oil trees in Iran cultural forests, the present situation and difficulties of gurjun-oil tress and the Buddhist way concerning the conservation and revitalization of them in Iran cultural forests. Approach: A qualitative research was applied to find the data in 7 forest areas of the province of Yasothon, Roi ET, Sisaket, Ubonratchathani, Burirum, Mahasarakham and Kakasin. The sample of 147 people was selected by ...

  19. SYNTAXOMOMICAL SURVEY O F EUROPEAN BEECH FORESTS: SOME GENERAL CONCLUSIONS

    Directory of Open Access Journals (Sweden)

    H. DIERSCHKE

    1997-01-01

    Full Text Available A short overwiev is given about the historical development of syntaxonomy of European beech forests. Different solutions of classification have been proposed, following more or less two main approaches: Division of alliances and suballiances by ecologically or geographically orientated species groups. A new classification of European beech forests is proposed with 8 (or more geographically orientated alliances, which can be further divided into suballiances by ecological species groups. For each alliance character and differential species, nomenclatural type and the area is mentioned, based on a (non puplished synthetic table, including 10.006 relevés from all parts of Europe. From this table also some overlapping species groups (a-n are given.

  20. 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

  1. Genetically engineered trees for plantation forests: key considerations for environmental risk assessment.

    Science.gov (United States)

    Häggman, Hely; Raybould, Alan; Borem, Aluizio; Fox, Thomas; Handley, Levis; Hertzberg, Magnus; Lu, Meng-Zu; Macdonald, Philip; Oguchi, Taichi; Pasquali, Giancarlo; Pearson, Les; Peter, Gary; Quemada, Hector; Séguin, Armand; Tattersall, Kylie; Ulian, Eugênio; Walter, Christian; McLean, Morven

    2013-09-01

    Forests are vital to the world's ecological, social, cultural and economic well-being yet sustainable provision of goods and services from forests is increasingly challenged by pressures such as growing demand for wood and other forest products, land conversion and degradation, and climate change. Intensively managed, highly productive forestry incorporating the most advanced methods for tree breeding, including the application of genetic engineering (GE), has tremendous potential for producing more wood on less land. However, the deployment of GE trees in plantation forests is a controversial topic and concerns have been particularly expressed about potential harms to the environment. This paper, prepared by an international group of experts in silviculture, forest tree breeding, forest biotechnology and environmental risk assessment (ERA) that met in April 2012, examines how the ERA paradigm used for GE crop plants may be applied to GE trees for use in plantation forests. It emphasizes the importance of differentiating between ERA for confined field trials of GE trees, and ERA for unconfined or commercial-scale releases. In the case of the latter, particular attention is paid to characteristics of forest trees that distinguish them from shorter-lived plant species, the temporal and spatial scale of forests, and the biodiversity of the plantation forest as a receiving environment. © 2013 ILSI Research Foundation. Plant Biotechnology Journal published by Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

  2. Genetically engineered trees for plantation forests: key considerations for environmental risk assessment

    Science.gov (United States)

    Häggman, Hely; Raybould, Alan; Borem, Aluizio; Fox, Thomas; Handley, Levis; Hertzberg, Magnus; Lu, Meng-Zu; Macdonald, Philip; Oguchi, Taichi; Pasquali, Giancarlo; Pearson, Les; Peter, Gary; Quemada, Hector; Séguin, Armand; Tattersall, Kylie; Ulian, Eugênio; Walter, Christian; McLean, Morven

    2013-01-01

    Forests are vital to the world's ecological, social, cultural and economic well-being yet sustainable provision of goods and services from forests is increasingly challenged by pressures such as growing demand for wood and other forest products, land conversion and degradation, and climate change. Intensively managed, highly productive forestry incorporating the most advanced methods for tree breeding, including the application of genetic engineering (GE), has tremendous potential for producing more wood on less land. However, the deployment of GE trees in plantation forests is a controversial topic and concerns have been particularly expressed about potential harms to the environment. This paper, prepared by an international group of experts in silviculture, forest tree breeding, forest biotechnology and environmental risk assessment (ERA) that met in April 2012, examines how the ERA paradigm used for GE crop plants may be applied to GE trees for use in plantation forests. It emphasizes the importance of differentiating between ERA for confined field trials of GE trees, and ERA for unconfined or commercial-scale releases. In the case of the latter, particular attention is paid to characteristics of forest trees that distinguish them from shorter-lived plant species, the temporal and spatial scale of forests, and the biodiversity of the plantation forest as a receiving environment. PMID:23915092

  3. Tree-Species Classification in Subtropical Forests Using Airborne Hyperspectral and LiDAR Data

    OpenAIRE

    Xin Shen; Lin Cao

    2017-01-01

    Accurate classification of tree-species is essential for sustainably managing forest resources and effectively monitoring species diversity. In this study, we used simultaneously acquired hyperspectral and LiDAR data from LiCHy (Hyperspectral, LiDAR and CCD) airborne system to classify tree-species in subtropical forests of southeast China. First, each individual tree crown was extracted using the LiDAR data by a point cloud segmentation algorithm (PCS) and the sunlit portion of each crown wa...

  4. Dynamics of transpiration, sap flow and use of stored water in tropical forest canopy trees.

    Science.gov (United States)

    Frederick C. Meinzer; Shelley A. James; Guillermo. Goldstein

    2004-01-01

    In large trees the daily onset of transpiration causes water to be withdrawn from internal storage compartments resulting in lags between changes in transpiration and sap flow at the base of the tree. We measured time courses of sap flow, hydraulic resistance, plant water potential and stomatal resistance in co-occuring tropical forest canopy trees with trunk diameters...

  5. Modeling Tree Mortality Following Wildfire in Pinus ponderosa Forests in the Central Sierra Nevada of California

    Science.gov (United States)

    Susan G. Conard; Jon C. Regelbrugge

    1993-01-01

    Abstract. We modeled tree mortality occurring two years following wildfire in Pinus ponderosa forests using data from 1275 trees in 25 stands burned during the 1987 Stanislaus Complex fires. We used logistic regression analysis to develop models relating the probability of wildfire-induced mortality with tree size and fire severity for Pinus ponderosa, Calocedrus...

  6. A computerized tree growth projection system for forest resource evaluation in the lake states

    Science.gov (United States)

    Allen L. Lundgren; Burton L. Essex

    1978-01-01

    A computerized tree growth projection system has been developed for the Lake States Region as part of a larger Forest Resources Evaluation Program (FREP). Incorporating data from more than 1500 permanent growth plots throughout the Lake States, this system projects tree growth, mortality, regeneration, and removals in stands with any mixture of tree species and sizes,...

  7. Fuel treatment effects on tree mortality following wildfire in dry mixed conifer forests, Washington State, USA

    Science.gov (United States)

    Susan J. Prichard; Maureen C. Kennedy

    2012-01-01

    Fuel reduction treatments are increasingly used to mitigate future wildfire severity in dry forests, but few opportunities exist to assess their effectiveness. We evaluated the influence of fuel treatment, tree size and species on tree mortality following a large wildfire event in recent thin-only, thin and prescribed burn (thin-Rx) units. Of the trees that died within...

  8. Temperature and rainfall strongly drive temporal growth variation in Asian tropical forest trees

    NARCIS (Netherlands)

    Vlam, M.; Baker, P.J.; Bunyavejchewin, S.; Zuidema, P.A.

    2014-01-01

    Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the

  9. Tree and forest effects on air quality and human health in the United States

    Science.gov (United States)

    David J. Nowak; Satoshi Hirabayashi; Allison Bodine; Eric. Greenfield

    2014-01-01

    Trees remove air pollution by the interception of particulate matter on plant surfaces and the absorption of gaseous pollutants through the leaf stomata. However, the magnitude and value of the effects of trees and forests on air quality and human health across the United States remains unknown. Computer simulations with local environmental data reveal that trees and...

  10. Crown dynamics and wood production of Douglas-fir trees in an old-growth forest

    Science.gov (United States)

    H. Roaki Ishii; Stephen C. Sillett; Allyson L. Carroll

    2017-01-01

    Large trees are the most prominent structural features of old-growth forests, which are considered to be globally important carbon sinks. Because of their large size, estimates of biomass and growth of large trees are often based on ground-level measurements (e.g., diameter at breast height, DBH) and little is known about growth dynamics within the crown. As trees...

  11. Potential Effects of Drought on Tree Dieback in Great Britain and Implications for Forest Management in Adaptation to Climate Change

    Science.gov (United States)

    Yu, Jianjun; Berry, Pam

    2017-04-01

    The drought and heat stress has alerted the composition, structure and biogeography of forests globally, whilst the projected severe and widespread droughts are potentially increasing. This challenges the sustainable forest management to better cope with future climate and maintain the forest ecosystem functions and services. Many studies have investigated the climate change impacts on forest ecosystem but less considered the climate extremes like drought. In this study, we implement a dynamic ecosystem model based on a version of LPJ-GUESS parameterized with European tree species and apply to Great Britain at a finer spatial resolution of 5*5 km. The model runs for the baseline from 1961 to 2011 and projects to the latter 21st century using 100 climate scenarios generated from MaRIUS project to tackle the climate model uncertainty. We will show the potential impacts of climate change on forest ecosystem and vegetation transition in Great Britain by comparing the modelled conditions in the 2030s and the 2080s relative to the baseline. In particular, by analyzing the modelled tree mortality, we will show the tree dieback patterns in response to drought for various species, and assess their drought vulnerability across Great Britain. We also use species distribution modelling to project the suitable climate space for selected tree species using the same climate scenarios. Aided by these two modelling approaches and based on the corresponding modelling results, we will discuss the implications for adaptation strategy for forest management, especially in extreme drought conditions. The gained knowledge and lessons for Great Britain are considered to be transferable in many other regions.

  12. Landscape variation in tree species richness in northern Iran forests.

    Directory of Open Access Journals (Sweden)

    Charles P-A Bourque

    Full Text Available Mapping landscape variation in tree species richness (SR is essential to the long term management and conservation of forest ecosystems. The current study examines the prospect of mapping field assessments of SR in a high-elevation, deciduous forest in northern Iran as a function of 16 biophysical variables representative of the area's unique physiography, including topography and coastal placement, biophysical environment, and forests. Basic to this study is the development of moderate-resolution biophysical surfaces and associated plot-estimates for 202 permanent sampling plots. The biophysical variables include: (i three topographic variables generated directly from the area's digital terrain model; (ii four ecophysiologically-relevant variables derived from process models or from first principles; and (iii seven variables of Landsat-8-acquired surface reflectance and two, of surface radiance. With symbolic regression, it was shown that only four of the 16 variables were needed to explain 85% of observed plot-level variation in SR (i.e., wind velocity, surface reflectance of blue light, and topographic wetness indices representative of soil water content, yielding mean-absolute and root-mean-squared error of 0.50 and 0.78, respectively. Overall, localised calculations of wind velocity and surface reflectance of blue light explained about 63% of observed variation in SR, with wind velocity accounting for 51% of that variation. The remaining 22% was explained by linear combinations of soil-water-related topographic indices and associated thresholds. In general, SR and diversity tended to be greatest for plots dominated by Carpinus betulus (involving ≥ 33% of all trees in a plot, than by Fagus orientalis (median difference of one species. This study provides a significant step towards describing landscape variation in SR as a function of modelled and satellite-based information and symbolic regression. Methods in this study are sufficiently

  13. 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.

  14. Facilitative-Competitive Interactions in an Old-Growth Forest: The Importance of Large-Diameter Trees as Benefactors and Stimulators for Forest Community Assembly

    Science.gov (United States)

    Fichtner, Andreas; Forrester, David I.; Härdtle, Werner; Sturm, Knut; von Oheimb, Goddert

    2015-01-01

    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. PMID:25803035

  15. Detecting Drought-Induced Tree Mortality in Sierra Nevada Forests with Time Series of Satellite Data

    OpenAIRE

    Sarah Byer; Yufang Jin

    2017-01-01

    A five-year drought in California led to a significant increase in tree mortality in the Sierra Nevada forests from 2012 to 2016. Landscape level monitoring of forest health and tree dieback is critical for vegetation and disaster management strategies. We examined the capability of multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) in detecting and explaining the impacts of the recent severe drought in Sierra Nevada forests. Remote sensing metrics were devel...

  16. Interacting Factors Driving a Major Loss of Large Trees with Cavities in a Forest Ecosystem

    Science.gov (United States)

    Lindenmayer, David B.; Blanchard, Wade; McBurney, Lachlan; Blair, David; Banks, Sam; Likens, Gene E.; Franklin, Jerry F.; Laurance, William F.; Stein, John A. R.; Gibbons, Philip

    2012-01-01

    Large trees with cavities provide critical ecological functions in forests worldwide, including vital nesting and denning resources for many species. However, many ecosystems are experiencing increasingly rapid loss of large trees or a failure to recruit new large trees or both. We quantify this problem in a globally iconic ecosystem in southeastern Australia – forests dominated by the world's tallest angiosperms, Mountain Ash (Eucalyptus regnans). Tree, stand and landscape-level factors influencing the death and collapse of large living cavity trees and the decay and collapse of dead trees with cavities are documented using a suite of long-term datasets gathered between 1983 and 2011. The historical rate of tree mortality on unburned sites between 1997 and 2011 was >14% with a mortality spike in the driest period (2006–2009). Following a major wildfire in 2009, 79% of large living trees with cavities died and 57–100% of large dead trees were destroyed on burned sites. Repeated measurements between 1997 and 2011 revealed no recruitment of any new large trees with cavities on any of our unburned or burned sites. Transition probability matrices of large trees with cavities through increasingly decayed condition states projects a severe shortage of large trees with cavities by 2039 that will continue until at least 2067. This large cavity tree crisis in Mountain Ash forests is a product of: (1) the prolonged time required (>120 years) for initiation of cavities; and (2) repeated past wildfires and widespread logging operations. These latter factors have resulted in all landscapes being dominated by stands ≤72 years and just 1.16% of forest being unburned and unlogged. We discuss how the features that make Mountain Ash forests vulnerable to a decline in large tree abundance are shared with many forest types worldwide. PMID:23071486

  17. Effects of tree species composition on within-forest distribution of understorey species

    NARCIS (Netherlands)

    Oijen, van D.; Feijen, M.; Hommel, P.W.F.M.; Ouden, den J.; Waal, de R.W.

    2005-01-01

    Question: Do tree species, with different litter qualities, affect the within-forest distribution of forest understorey species on intermediate to base-rich soils? Since habitat loss and fragmentation have caused ancient forest species to decline, those species are the main focus of this study.

  18. Invasion by native tree species prevents biotic homogenization in novel forests of Puerto Rico

    Science.gov (United States)

    Oscar J. Abelleira Martinez

    2010-01-01

    There is concern that secondary forests dominated by introduced species, known as novel forests, increase taxonomical similarity between localities and lead to biotic homogenization in human dominated landscapes. In Puerto Rico, agricultural abandonment has given way to novel forests dominated by the introduced African tulip tree Spathodea campanulata Beauv. (...

  19. Growing the urban forest: tree performance in response to biotic and abiotic land management

    Science.gov (United States)

    Emily E. Oldfield; Alexander J. Felson; D. S. Novem Auyeung; Thomas W. Crowther; Nancy F. Sonti; Yoshiki Harada; Daniel S. Maynard; Noah W. Sokol; Mark S. Ashton; Robert J. Warren; Richard A. Hallett; Mark A. Bradford

    2015-01-01

    Forests are vital components of the urban landscape because they provide ecosystem services such as carbon sequestration, storm-water mitigation, and air-quality improvement. To enhance these services, cities are investing in programs to create urban forests. A major unknown, however, is whether planted trees will grow into the mature, closed-canopied forest on which...

  20. Spatial and temporal analysis of the anthropogenic effects on local diversity of forest trees

    National Research Council Canada - National Science Library

    Polyakov, Maksym; Majumdar, Indrajit; Teeter, Lawrence

    2008-01-01

    ... variety of goods and services to humans. Tree diversity is a key component of forest ecosystem biodiversity and this is one of the reasons why biodiversity has emerged as a major objective of forest management and conservation since the Earth Summit in Rio de Janeiro in 1992. Forest diversity is an important criterion of sustainable for...

  1. Are forest disturbances amplifying or canceling out climate change-induced productivity changes in European forests?

    Science.gov (United States)

    Reyer, Christopher P O; Bathgate, Stephen; Blennow, Kristina; Borges, Jose G; Bugmann, Harald; Delzon, Sylvain; Faias, Sonia P; Garcia-Gonzalo, Jordi; Gardiner, Barry; Gonzalez-Olabarria, Jose Ramon; Gracia, Carlos; Hernández, Juan Guerra; Kellomäki, Seppo; Kramer, Koen; Lexer, Manfred J; Lindner, Marcus; van der Maaten, Ernst; Maroschek, Michael; Muys, Bart; Nicoll, Bruce; Palahi, Marc; Palma, João Hn; Paulo, Joana A; Peltola, Heli; Pukkala, Timo; Rammer, Werner; Ray, Duncan; Sabaté, Santiago; Schelhaas, Mart-Jan; Seidl, Rupert; Temperli, Christian; Tomé, Margarida; Yousefpour, Rasoul; Zimmermann, Niklaus E; Hanewinkel, Marc

    2017-03-16

    Recent studies projecting future climate change impacts on forests mainly consider either the effects of climate change on productivity or on disturbances. However, productivity and disturbances are intrinsically linked because 1) disturbances directly affect forest productivity (e.g. via a reduction in leaf area, growing stock or resource-use efficiency), and 2) disturbance susceptibility is often coupled to a certain development phase of the forest with productivity determining the time a forest is in this specific phase of susceptibility. The objective of this paper is to provide an overview of forest productivity changes in different forest regions in Europe under climate change, and partition these changes into effects induced by climate change alone and by climate change and disturbances. We present projections of climate change impacts on forest productivity from state-of-the-art forest models that dynamically simulate forest productivity and the effects of the main European disturbance agents (fire, storm, insects), driven by the same climate scenario in seven forest case studies along a large climatic gradient throughout Europe. Our study shows that, in most cases, including disturbances in the simulations exaggerate ongoing productivity declines or cancel out productivity gains in response to climate change. In fewer cases, disturbances also increase productivity or buffer climate-change induced productivity losses, e.g. because low severity fires can alleviate resource competition and increase fertilization. Even though our results cannot simply be extrapolated to other types of forests and disturbances, we argue that it is necessary to interpret climate change-induced productivity and disturbance changes jointly to capture the full range of climate change impacts on forests and to plan adaptation measures.

  2. Are forest disturbances amplifying or canceling out climate change-induced productivity changes in European forests?

    Science.gov (United States)

    Reyer, Christopher P. O.; Bathgate, Stephen; Blennow, Kristina; Borges, Jose G.; Bugmann, Harald; Delzon, Sylvain; Faias, Sonia P.; Garcia-Gonzalo, Jordi; Gardiner, Barry; Gonzalez-Olabarria, Jose Ramon; Gracia, Carlos; Guerra Hernández, Juan; Kellomäki, Seppo; Kramer, Koen; Lexer, Manfred J.; Lindner, Marcus; van der Maaten, Ernst; Maroschek, Michael; Muys, Bart; Nicoll, Bruce; Palahi, Marc; Palma, João HN; Paulo, Joana A.; Peltola, Heli; Pukkala, Timo; Rammer, Werner; Ray, Duncan; Sabaté, Santiago; Schelhaas, Mart-Jan; Seidl, Rupert; Temperli, Christian; Tomé, Margarida; Yousefpour, Rasoul; Zimmermann, Niklaus E.; Hanewinkel, Marc

    2017-03-01

    Recent studies projecting future climate change impacts on forests mainly consider either the effects of climate change on productivity or on disturbances. However, productivity and disturbances are intrinsically linked because 1) disturbances directly affect forest productivity (e.g. via a reduction in leaf area, growing stock or resource-use efficiency), and 2) disturbance susceptibility is often coupled to a certain development phase of the forest with productivity determining the time a forest is in this specific phase of susceptibility. The objective of this paper is to provide an overview of forest productivity changes in different forest regions in Europe under climate change, and partition these changes into effects induced by climate change alone and by climate change and disturbances. We present projections of climate change impacts on forest productivity from state-of-the-art forest models that dynamically simulate forest productivity and the effects of the main European disturbance agents (fire, storm, insects), driven by the same climate scenario in seven forest case studies along a large climatic gradient throughout Europe. Our study shows that, in most cases, including disturbances in the simulations exaggerate ongoing productivity declines or cancel out productivity gains in response to climate change. In fewer cases, disturbances also increase productivity or buffer climate-change induced productivity losses, e.g. because low severity fires can alleviate resource competition and increase fertilization. Even though our results cannot simply be extrapolated to other types of forests and disturbances, we argue that it is necessary to interpret climate change-induced productivity and disturbance changes jointly to capture the full range of climate change impacts on forests and to plan adaptation measures.

  3. Are forest disturbances amplifying or canceling out climate change-induced productivity changes in European forests?

    Science.gov (United States)

    Reyer, Christopher P O; Bathgate, Stephen; Blennow, Kristina; Borges, Jose G; Bugmann, Harald; Delzon, Sylvain; Faias, Sonia P; Garcia-Gonzalo, Jordi; Gardiner, Barry; Gonzalez-Olabarria, Jose Ramon; Gracia, Carlos; Hernández, Juan Guerra; Kellomäki, Seppo; Kramer, Koen; Lexer, Manfred J; Lindner, Marcus; van der Maaten, Ernst; Maroschek, Michael; Muys, Bart; Nicoll, Bruce; Palahi, Marc; Palma, João HN; Paulo, Joana A; Peltola, Heli; Pukkala, Timo; Rammer, Werner; Ray, Duncan; Sabaté, Santiago; Schelhaas, Mart-Jan; Seidl, Rupert; Temperli, Christian; Tomé, Margarida; Yousefpour, Rasoul; Zimmermann, Niklaus E; Hanewinkel, Marc

    2017-01-01

    Recent studies projecting future climate change impacts on forests mainly consider either the effects of climate change on productivity or on disturbances. However, productivity and disturbances are intrinsically linked because 1) disturbances directly affect forest productivity (e.g. via a reduction in leaf area, growing stock or resource-use efficiency), and 2) disturbance susceptibility is often coupled to a certain development phase of the forest with productivity determining the time a forest is in this specific phase of susceptibility. The objective of this paper is to provide an overview of forest productivity changes in different forest regions in Europe under climate change, and partition these changes into effects induced by climate change alone and by climate change and disturbances. We present projections of climate change impacts on forest productivity from state-of-the-art forest models that dynamically simulate forest productivity and the effects of the main European disturbance agents (fire, storm, insects), driven by the same climate scenario in seven forest case studies along a large climatic gradient throughout Europe. Our study shows that, in most cases, including disturbances in the simulations exaggerate ongoing productivity declines or cancel out productivity gains in response to climate change. In fewer cases, disturbances also increase productivity or buffer climate-change induced productivity losses, e.g. because low severity fires can alleviate resource competition and increase fertilization. Even though our results cannot simply be extrapolated to other types of forests and disturbances, we argue that it is necessary to interpret climate change-induced productivity and disturbance changes jointly to capture the full range of climate change impacts on forests and to plan adaptation measures. PMID:28855959

  4. Simulation of Tsunami Resistance of a Pinus Thunbergii tree in Coastal Forest in Japan

    Science.gov (United States)

    Nanko, K.; Suzuki, S.; Noguchi, H.; Hagino, H.

    2015-12-01

    Forests reduce fluid force of tsunami, whereas extreme tsunami sometimes breaks down the forest trees. It is difficult to estimate the interactive relationship between the fluid and the trees because fluid deform tree architecture and deformed tree changes flow field. Dynamic tree deformation and fluid behavior should be clarified by fluid-structure interaction analysis. For the initial step, we have developed dynamic simulation of tree sway and breakage caused by tsunami based on a vibrating system with multiple degrees of freedom. The target specie of the simulation was Japanese black pine (pinus thunbergii), which is major specie in the coastal forest to secure livelihood area from the damage by blown sand and salt in Japanese coastal area. For the simulation, a tree was segmented into 0.2 m long circular truncated cones. Turning moment induced by tsunami and self-weight was calculated at each segment bottom. Tree deformation was computed on multi-degree-of-freedom vibration equation. Tree sway was simulated by iterative calculation of the tree deformation with time step 0.05 second with temporally varied flow velocity of tsunami. From the calculation of bending stress and turning moment at tree base, we estimated resistance of a Pinus thunbergii tree from tsunami against tree breakage.

  5. Does Forest Continuity Enhance the Resilience of Trees to Environmental Change?

    Directory of Open Access Journals (Sweden)

    Goddert von Oheimb

    Full Text Available There is ample evidence that continuously existing forests and afforestations on previously agricultural land differ with regard to ecosystem functions and services such as carbon sequestration, nutrient cycling and biodiversity. However, no studies have so far been conducted on possible long-term (>100 years impacts on tree growth caused by differences in the ecological continuity of forest stands. In the present study we analysed the variation in tree-ring width of sessile oak (Quercus petraea (Matt. Liebl. trees (mean age 115-136 years due to different land-use histories (continuously existing forests, afforestations both on arable land and on heathland. We also analysed the relation of growth patterns to soil nutrient stores and to climatic parameters (temperature, precipitation. Tree rings formed between 1896 and 2005 were widest in trees afforested on arable land. This can be attributed to higher nitrogen and phosphorous availability and indicates that former fertilisation may continue to affect the nutritional status of forest soils for more than one century after those activities have ceased. Moreover, these trees responded more strongly to environmental changes - as shown by a higher mean sensitivity of the tree-ring widths - than trees of continuously existing forests. However, the impact of climatic parameters on the variability in tree-ring width was generally small, but trees on former arable land showed the highest susceptibility to annually changing climatic conditions. We assume that incompletely developed humus horizons as well as differences in the edaphon are responsible for the more sensitive response of oak trees of recent forests (former arable land and former heathland to variation in environmental conditions. We conclude that forests characterised by a long ecological continuity may be better adapted to global change than recent forest ecosystems.

  6. Tree species composition affects the abundance of rowan (Sorbus aucuparia L.) in urban forests in Finland.

    Science.gov (United States)

    Hamberg, Leena; Lehvävirta, Susanna; Kotze, D Johan; Heikkinen, Juha

    2015-03-15

    Recent studies have shown a considerable increase in the abundance of rowan (Sorbus aucuparia) saplings in urban forests in Finland, yet the reasons for this increase are not well understood. Here we investigated whether canopy cover or tree species composition, i.e., the basal areas of different tree species in Norway spruce dominated urban forests, affects the abundances of rowan seedlings, saplings and trees. Altogether 24 urban forest patches were investigated. We sampled the number of rowan and other saplings, and calculated the basal areas of trees. We showed that rowan abundance was affected by tree species composition. The basal area of rowan trees (≥ 5 cm in diameter at breast height, dbh) decreased with increasing basal area of Norway spruce, while the cover of rowan seedlings increased with an increase in Norway spruce basal area. However, a decrease in the abundance of birch (Betula pendula) and an increase in the broad-leaved tree group (Acer platanoides, Alnus glutinosa, Alnus incana, Amelanchier spicata, Prunus padus, Quercus robur, Rhamnus frangula and Salix caprea) coincided with a decreasing number of rowans. Furthermore, rowan saplings were scarce in the vicinity of mature rowan trees. Although it seems that tree species composition has an effect on rowan, the relationship between rowan saplings and mature trees is complex, and therefore we conclude that regulating tree species composition is not an easy way to keep rowan thickets under control in urban forests in Finland. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Disentangling the diversity of arboreal ant communities in tropical forest trees.

    Science.gov (United States)

    Klimes, Petr; Fibich, Pavel; Idigel, Cliffson; Rimandai, Maling

    2015-01-01

    Tropical canopies are known for their high abundance and diversity of ants. However, the factors which enable coexistence of so many species in trees, and in particular, the role of foragers in determining local diversity, are not well understood. We censused nesting and foraging arboreal ant communities in two 0.32 ha plots of primary and secondary lowland rainforest in New Guinea and explored their species diversity and composition. Null models were used to test if the records of species foraging (but not nesting) in a tree were dependent on the spatial distribution of nests in surrounding trees. In total, 102 ant species from 389 trees occurred in the primary plot compared with only 50 species from 295 trees in the secondary forest plot. However, there was only a small difference in mean ant richness per tree between primary and secondary forest (3.8 and 3.3 sp. respectively) and considerably lower richness per tree was found only when nests were considered (1.5 sp. in both forests). About half of foraging individuals collected in a tree belonged to species which were not nesting in that tree. Null models showed that the ants foraging but not nesting in a tree are more likely to nest in nearby trees than would be expected at random. The effects of both forest stage and tree size traits were similar regardless of whether only foragers, only nests, or both datasets combined were considered. However, relative abundance distributions of species differed between foraging and nesting communities. The primary forest plot was dominated by native ant species, whereas invasive species were common in secondary forest. This study demonstrates the high contribution of foragers to arboreal ant diversity, indicating an important role of connectivity between trees, and also highlights the importance of primary vegetation for the conservation of native ant communities.

  8. Detecting Drought-Induced Tree Mortality in Sierra Nevada Forests with Time Series of Satellite Data

    Directory of Open Access Journals (Sweden)

    Sarah Byer

    2017-09-01

    Full Text Available A five-year drought in California led to a significant increase in tree mortality in the Sierra Nevada forests from 2012 to 2016. Landscape level monitoring of forest health and tree dieback is critical for vegetation and disaster management strategies. We examined the capability of multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS in detecting and explaining the impacts of the recent severe drought in Sierra Nevada forests. Remote sensing metrics were developed to represent baseline forest health conditions and drought stress using time series of MODIS vegetation indices (VIs and a water index. We used Random Forest algorithms, trained with forest aerial detection surveys data, to detect tree mortality based on the remote sensing metrics and topographical variables. Map estimates of tree mortality demonstrated that our two-stage Random Forest models were capable of detecting the spatial patterns and severity of tree mortality, with an overall producer’s accuracy of 96.3% for the classification Random Forest (CRF and a RMSE of 7.19 dead trees per acre for the regression Random Forest (RRF. The overall omission errors of the CRF ranged from 19% for the severe mortality class to 27% for the low mortality class. Interpretations of the models revealed that forests with higher productivity preceding the onset of drought were more vulnerable to drought stress and, consequently, more likely to experience tree mortality. This method highlights the importance of incorporating baseline forest health data and measurements of drought stress in understanding forest response to severe drought.

  9. Ecology and pathology of European chestnut (Castanea sativa) in the deciduous forests of the Caucasus Mountains in southern Russia

    Science.gov (United States)

    Pridnya, M.V.; Cherpakov, V.V.; Paillet, Frederick L.

    1996-01-01

    Chestnut-dominated forests of the Caucasus Mountain area of Russia are very similar to former chestnut-dominated forests in eastern North America. The distribution, pathology, and reproductive status of European chestnut (Castanea sativa) in the Caucasus are described and compared to that of American chestnut (C. dentata). Chestnut forests are distributed continuously along the southern slope of the Caucasus mountains near the Black Sea, and are found in isolated populations on the north side of the Caucasus, at elevations ranging from 200 to 1300 meters. Chestnut blight was apparently introduced into the region after 1880 and continues to destroy chestnut forests today. Chestnut in the Caucasus is also infected by several other fungal and bacterial parasites and the joint infection of blight and bacteria may be especially dangerous for chestnut trees. Chestnut-dominated forests comprise only a few percent of total forest cover in the Caucasus Biosphere Preserve, and usually occur in mountain valleys or coves with deep brown soil. The age structure and reproductive status of chestnut in the Caucasus was investigated on six study plots in the Caucasus Biosphere Forest Preserve near the upper altitudinal limit of chestnut. Although chestnut is at least 70 percent of the overstory on these sites, there are very few trees less than 50 years old, and very few recent seedlings on any of the plots. Most large chestnut trees appear to have originated as basal spouts from previously established stems. Although chestnut seed production appears adequate, we suspect that competition with shrubs and other tree seedlings, and predation by herbivores and rodents, now prevent the establishment and survival of chestnut seedlings in the Biosphere Preserve.

  10. Forests, trees and human health and well-being

    DEFF Research Database (Denmark)

    Nilsson, Kjell Svenne Bernhard; Sangster, Marcus; Konijnendijk, Cecil Cornelis

    2011-01-01

    The link between modern lifestyles and increasing levels of chronic heart disease, obesity, stress and poor mental health is a concern across the world. The cost of dealing with these conditions places a large burden on national public health budgets so that policymakers are increasingly looking...... at prevention as a cost-effective alternative to medical treatment. Attention is turning towards interactions between the environment and lifestyles. Exploring the relationships between health, natural environments in general, and forests in particular, this groundbreaking book is the outcome of the European......, providing a vital reference for researchers in forestry, health, natural resource management and environmental policy. Currently the only unified body of work on this topic, the book will also be an important tool for those working in both health and environment policy and practice....

  11. 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.

  12. Tree Species Establishment in Urban Forest in Relation to Vegetation Composition, Tree Canopy Gap Area and Soil Factors

    Directory of Open Access Journals (Sweden)

    Ilze Jankovska

    2015-12-01

    Full Text Available The study of density and growth of pine, birch and oak seedlings and saplings in canopy gaps in the urban boreal forest in Riga, Latvia, indicates that natural regeneration can increase diversity in small gaps caused by tree mortality, and can ensure conversion from even-aged pine forest. Abundant regeneration in small gaps showed that light (gap area was only one of the factors affecting tree regeneration in the gaps. The depth of the O layer and pH were suggested to be important factors for the establishment and growth of pine and birch. For oak, the main factors for establishment and growth were favorable moisture, higher pH and N concentration. Knowledge of ecological factors affecting the establishment of seedlings and growth of saplings of the most common trees species in the urban boreal forest is needed to predict successional trajectories and to aid management.

  13. Marbled Murrelets Select Distinctive Nest Trees within Old-Growth Forest Patches

    Directory of Open Access Journals (Sweden)

    Michael P. Silvergieter

    2011-12-01

    Full Text Available The coastal old-growth forests of North America's Pacific Coast are renowned both for their commercial and ecological value. This study adds to growing evidence that selective harvesting of the largest trees may have a disproportionate ecological impact. Marbled Murrelets (Brachyramphus marmoratus, a threatened species, nest almost exclusively in these old-growth forests. Detailed knowledge of nesting habitat selection provides guidance for habitat management and conservation. Habitat selection for this species has been studied at a variety of scales using ground and remote methods. However, because Marbled Murrelet nesting activity is limited to a single mossy platform on a single tree, we investigated nest tree selection within old-growth forest patches, using a set of 59 forest patches containing active nests. Nest trees were usually distinctive compared with neighboring trees in the surrounding 25 m radius patch. They averaged 15 to 20% taller than neighboring trees depending on region, had significantly larger stem diameters, more potential nesting platforms, and more moss. They had the most extreme values of height and width about three times as often as expected by chance. An analysis of moss platform use as a function of number of platforms per platform tree suggests that murrelets select individual platforms, rather than platform trees per se. Nonetheless, highly selective logging practices that remove high-value trees from stands may also remove trees most likely to be selected by nesting murrelets.

  14. Long tree-ring chronologies provide evidence of recent tree growth decrease in a Central African tropical forest.

    Directory of Open Access Journals (Sweden)

    Giovanna Battipaglia

    Full Text Available It is still unclear whether the exponential rise of atmospheric CO2 concentration has produced a fertilization effect on tropical forests, thus incrementing their growth rate, in the last two centuries. As many factors affect tree growth patterns, short -term studies might be influenced by the confounding effect of several interacting environmental variables on plant growth. Long-term analyses of tree growth can elucidate long-term trends of plant growth response to dominant drivers. The study of annual rings, applied to long tree-ring chronologies in tropical forest trees enables such analysis. Long-term tree-ring chronologies of three widespread African species were measured in Central Africa to analyze the growth of trees over the last two centuries. Growth trends were correlated to changes in global atmospheric CO2 concentration and local variations in the main climatic drivers, temperature and rainfall. Our results provided no evidence for a fertilization effect of CO2 on tree growth. On the contrary, an overall growth decline was observed for all three species in the last century, which appears to be significantly correlated to the increase in local temperature. These findings provide additional support to the global observations of a slowing down of C sequestration in the trunks of forest trees in recent decades. Data indicate that the CO2 increase alone has not been sufficient to obtain a tree growth increase in tropical trees. The effect of other changing environmental factors, like temperature, may have overridden the fertilization effect of CO2.

  15. Role of the bio-geocoenosis in the rooting zone of forest trees

    Energy Technology Data Exchange (ETDEWEB)

    Blaschke, H.; Baeumler, W.

    1986-06-01

    Interdisciplinary studies conducted in old-growth forests in Oregon and Bavaria were focused on structure and functions in the rooting zone of forest trees. In decayed trees and rotten stumps, offering multitudes of external and internal habitats, complex interactions occur between tree roots, mycorrhizal fungi, bacteria, and small mammals. Based on single components of the bio-geocenosis in the rooting zone, with emphasis on large woody residues and nitrogen stress as an important ecological factor, the impact of this habitat on the functional diversity related to forest ecosystems affected by Waldsterben is discussed.

  16. Tree species diversity and regeneration of tropical dry forests in Nicaragua

    OpenAIRE

    González-Rivas, Benigno

    2005-01-01

    The thesis summarises results from four studies in dry forests of Nicaragua aiming to gain knowledge supporting conservation and rehabilitation efforts in these highly threatened forests. In the first study, tree species composition, structure and diversity of dry deciduous and gallery forests was carried out in Chacocente National Wildlife Refuge during 1994 and 2000. A total of 29 families, 49 genera and 59 species were represented in 2 ha permanent plots in dry deciduous forest during 1994...

  17. Impacts of environmental stress on genetic structures of forest tree stands as exemplified by European beech (Fagus sylvatica L.); Auswirkungen von Umweltbelastungen auf genetische Strukturen von Waldbestaenden am Beispiel der Buche (Fagus sylvatica L.)

    Energy Technology Data Exchange (ETDEWEB)

    Mueller-Starck, G. [Goettingen Univ. (Germany). Inst. fuer Forstgenetik und Forstpflanzenzuechtung, Forstliche Biometrie und Informatik

    1993-12-31

    Inheritance of isoenzymes in European beech was verified by means of analysis of segregations among full-sib families. 42 alleles were shown to be controlled genetically by a total of 17 polymorphic gene loci. In six adult stands, genetic structures between tolerant and sensitive subsets were compared (574 individuals). Furthermore, in order to study the dynamics of genetic variation, genetic structures were compared between germinating seeds (initial populations) and survivors at the age of two years under various field stress conditions (2986 individuals). The following tendencies are evident: (1) Genetic structures deviate significantly between tolerant and sensitive subsets in adult stands and between initial populations and juvenile survivors. (2) In adult stands, tolerant subsets reveal greater observed heterozygosities than sensitive subsets (surplus of 23.1%). (3) Among juvenile survivors, severe losses of genetic multiplicity can be expected (at least 17% of alleles). (4) Much greater gene pool diversity is indicated in tolerant subsets as compared to sensitive ones (trends to greater evenness of frequency distributions). (5) In the expression of viability characters, additive allelic effects are suggested in adult stands, but the genetic background is complex in heterogeneous environments. (6) In juvenile survivors, genetic selection is clearly indicated. Environmental stress affects genetic structures of beech populations in many different ways. It is concluded that long term exposure to complex field stress results in a viability advantage for genetically diverse populations and individuals. In juvenile stages, certain alleles may account for superior viabilities, but this phenomenon does not seem to hold for succeeding life stages. In such environments, genetically heterogeneous populations are strongly suggested. (orig./UWa) [Deutsch] Ziel der Untersuchungen war die Ueberpruefung genetischer Auswirkungen von Umweltstress auf Altbestaende und

  18. Quantitative Analysis of Tree Species in Mixed Forests of Mandal Catchments, Garhwal Himalaya

    Directory of Open Access Journals (Sweden)

    Balwant KUMAR

    2012-06-01

    Full Text Available A total of 14 tree species were identified in the study sites, among which Quercus leucotrichophora Hook. F. (Banj oak, Rhododendron arboreum Smith (Burans, Lyonia ovalifolia Drude (Ayar and Pyrus pashia Buch-Hemp (Mehal are the predominant tree species. A quantitative analysis of tree species indicates that on the basis of their canopy cover, tree density and total base area, these study sites fall within the category of disturbed forest. The uncontrolled lopping for timber, firewood and leaf fodder and the absence of saplings and seedlings are some of the major factors responsible for the declining of forests in the Himalayan region.

  19. Long-term international impacts of nature-oriented forest management on European forests - an assessment with the EFISCEN model

    NARCIS (Netherlands)

    Nabuurs, G.J.; Goede, de D.M.; Michie, B.; Schelhaas, M.J.; Wesseling, J.G.

    2002-01-01

    Forest management in Europe is changing towards a multi-functional approach in which the role of nature conservation and wood production are given equal prominence. This nature-oriented forest management will result in a very different European forest in 50-100 years time, changing felling options

  20. Variability of European beech wood density as influenced by interactions between tree-ring growth and aspect

    Directory of Open Access Journals (Sweden)

    Daniela Diaconu

    2016-02-01

    Full Text Available Background: Wood density is considered to be the most important predictor of wood quality but despite its importance, diffuse-porous tree species have been the subject of only a limited number of studies. The importance of European beech forests for Central Europe calls for profound research to examine the potential impact of a warmer climate on the quality of beech timber. Methods: In this study we analysed the influence of tree-ring width and tree-ring age on the wood density of beech, and whether the wood density response to these two parameters is modified by aspect. A linear mixed-effects model for wood density was constructed for mean density data measured with high frequency densitometry on stem discs from 72 beech trees sampled from two different aspects (northeast -NE and southwest -SW of a valley in southwestern Germany. Results: Part of the variability of mean annual wood density was explained by cambial age: an increase in cambial age resulted in an increase in mean wood density. Tree-ring width and aspect had only a small influence on wood density. Wood density on the SW aspect was lower than on the NE with a difference of approximately 0.006 g/cm3. The between-tree variability was very high. Conclusions: The significant interaction between cambial age and aspect reflects the importance of site conditions at older tree ages: with increasing cambial age the difference between aspects becomes stronger. Our results give a better understanding of the importance of site conditions on the wood quality of beech. Keywords: Fagus sylvatica, HF densitometry, Wood quality, Wood density, Aspect

  1. Analysis of growth trend changes for 51 temperate tree species using Korea national forest inventory data

    Science.gov (United States)

    Park, M.; Moon, M.; Park, J.; Cho, S.; Kim, H. S.

    2016-12-01

    Individual tree growth rates can be affected by various factors such as species, soil fertility, stand development stage, disturbance, and climate etc. To estimate the effect of changes in tree growth rate on the structure and functionality of forest ecosystem in the future, we analyzed the change of species-specific growth trends using the fifth Korea national forest inventory data, which was collected from 2006 to 2010. The ring samples of average tree were collected from nationwide inventory plots and the total number of individual tree ring series was 69,128 covering 185 tree species. Among those, fifty one species with more than 100 tree ring series were used for our analysis. For growth-trend analysis, standardized regional curves of individual species growth were generated from three forest zone in South Korea; subarctic, cool temperate, warm temperate forest zone. Then individual tree ring series was indexed by dividing the growth of the tree by expected growth from standardized regional curves. Then the ratio of all tree ring series were aligned by year and the Spearman's correlation coefficient of each species was calculated. The results show that most of species had increasing growth rates as forests developed after Korean war. For the last thirty years, 67.3% of species including Quercus spp. and Zelkova serrata had positive growth trends, on the other hand, 11.5% of species including Pinus spp. showed negative growth trends probably due to the changes in successional stages in Korean forests and climate change. These trends also vary with climate zone and species. For examples, Pinus densiflora, which showed negative growth trend overall, had steep negative growth trends in boreal and temperate zone, whereas it showed no specific trend in sub-tropical climate zone. Our trend analysis on 51 temperate tree species growth will be essential to predict the temperate forests species change for the this century.

  2. Spatial pattern of tree diversity and evenness across forest types in Majella National Park, Italy

    Directory of Open Access Journals (Sweden)

    Mohammad Redowan

    2015-09-01

    Full Text Available Background Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to describe the structure of a biological community. Variation of the tree diversity and evenness with elevation, topographic relief, aspect, terrain shape, slope, soil nutrient, solar radiation etc. are well documented. Methods Present study explores the variation of tree diversity (measured as Shannon diversity and evenness indices of Majella National Park, Italy with five available forest types namely evergreen oak woods, deciduous oak woods, black/aleppo pine stands, hop-hornbeam forest and beech forest, using satellite, environmental and field data. Results Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even. Diversity and evenness of forest types were concurrent to each other i.e. forest type which was more diverse was also more even. As a broad pattern, majority portion of the study area belonged to medium diversity and high evenness class. Conclusions Satellite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types. Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majella.

  3. Modelling individual tree height to crown base of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.).

    Science.gov (United States)

    Sharma, Ram P; Vacek, Zdeněk; Vacek, Stanislav; Podrázský, Vilém; Jansa, Václav

    2017-01-01

    Height to crown base (HCB) of a tree is an important variable often included as a predictor in various forest models that serve as the fundamental tools for decision-making in forestry. We developed spatially explicit and spatially inexplicit mixed-effects HCB models using measurements from a total 19,404 trees of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) on the permanent sample plots that are located across the Czech Republic. Variables describing site quality, stand density or competition, and species mixing effects were included into the HCB model with use of dominant height (HDOM), basal area of trees larger in diameters than a subject tree (BAL- spatially inexplicit measure) or Hegyi's competition index (HCI-spatially explicit measure), and basal area proportion of a species of interest (BAPOR), respectively. The parameters describing sample plot-level random effects were included into the HCB model by applying the mixed-effects modelling approach. Among several functional forms evaluated, the logistic function was found most suited to our data. The HCB model for Norway spruce was tested against the data originated from different inventory designs, but model for European beech was tested using partitioned dataset (a part of the main dataset). The variance heteroscedasticity in the residuals was substantially reduced through inclusion of a power variance function into the HCB model. The results showed that spatially explicit model described significantly a larger part of the HCB variations [R2adj = 0.86 (spruce), 0.85 (beech)] than its spatially inexplicit counterpart [R2adj = 0.84 (spruce), 0.83 (beech)]. The HCB increased with increasing competitive interactions described by tree-centered competition measure: BAL or HCI, and species mixing effects described by BAPOR. A test of the mixed-effects HCB model with the random effects estimated using at least four trees per sample plot in the validation data confirmed that the

  4. Modelling individual tree height to crown base of Norway spruce (Picea abies (L. Karst. and European beech (Fagus sylvatica L..

    Directory of Open Access Journals (Sweden)

    Ram P Sharma

    Full Text Available Height to crown base (HCB of a tree is an important variable often included as a predictor in various forest models that serve as the fundamental tools for decision-making in forestry. We developed spatially explicit and spatially inexplicit mixed-effects HCB models using measurements from a total 19,404 trees of Norway spruce (Picea abies (L. Karst. and European beech (Fagus sylvatica L. on the permanent sample plots that are located across the Czech Republic. Variables describing site quality, stand density or competition, and species mixing effects were included into the HCB model with use of dominant height (HDOM, basal area of trees larger in diameters than a subject tree (BAL- spatially inexplicit measure or Hegyi's competition index (HCI-spatially explicit measure, and basal area proportion of a species of interest (BAPOR, respectively. The parameters describing sample plot-level random effects were included into the HCB model by applying the mixed-effects modelling approach. Among several functional forms evaluated, the logistic function was found most suited to our data. The HCB model for Norway spruce was tested against the data originated from different inventory designs, but model for European beech was tested using partitioned dataset (a part of the main dataset. The variance heteroscedasticity in the residuals was substantially reduced through inclusion of a power variance function into the HCB model. The results showed that spatially explicit model described significantly a larger part of the HCB variations [R2adj = 0.86 (spruce, 0.85 (beech] than its spatially inexplicit counterpart [R2adj = 0.84 (spruce, 0.83 (beech]. The HCB increased with increasing competitive interactions described by tree-centered competition measure: BAL or HCI, and species mixing effects described by BAPOR. A test of the mixed-effects HCB model with the random effects estimated using at least four trees per sample plot in the validation data confirmed

  5. Long-term Patterns of Climate, Tree Growth, and Tree Mortality in Permanent Forest Plots of Hawaii Island

    Science.gov (United States)

    Ostertag, R.; Buckley, W.; Cordell, S.; Giambelluca, T. W.; Giardina, C. P.; Inman-Narahari, F.; Litton, C. M.; Nullet, M.; Sack, L.; Sibley, A.; VanDeMark, J.

    2014-12-01

    Long-term permanent vegetation plots provide opportunities for in-depth examinations of forest dynamics and climate. We used Center for Tropical Forest Science (CTFS) methodology to establish 4-ha forest dynamics plots in two contrasting climates on Hawaii Island. We established a montane wet forest dynamics plot in a site with 1150 m elevation, mean annual temperature (MAT) of 16.0 C, and mean annual precipitation (MAP) of 3440 mm. A second plot was established in a lowland dry forest site at 240 m elevation, 20.0 C MAT, and 835 mm MAP. The lowland wet forest site averaged only one month per year with < 100 mm rainfall (considered a dry season month), while the lowland dry forest had 12 dry season months. All trees greater or equal to 1 cm diameter were tagged, mapped, and followed from 2008/2009 to 2013/2014 as part of a 5-year census, and a subset of trees were measured annually. Climate variables measured were shortwave and longwave radiation, air temperature, photosynthetically active radiation, relative humidity, windspeed, soil moisture, and rainfall. At both sites, rainfall was the best predictor of annual growth rates. Rainfall and soil moisture were the two variables that demonstrated the greatest interannual variation; coefficients of variation were 36.7% and 61.6% for rainfall at the montane wet forest and lowland dry forest sites, respectively, and 13.4% and 66.1% for soil moisture at the two sites. Preliminary results from the five-year resurvey demonstrate that Hawaiian trees grow slowly, averaging 0.05 cm/y among 19 species in the montane wet forest, at much slower rates for the 15 species in the lowland dry forest plot. Preliminary mortality rates are 11.8% in the montane wet forest and 14.5% in the lowland dry forest. Forest dynamics appear highly related to water availability, even in wet forests, and are likely to be sensitive to climate change, under which reduced rainfall is predicted for much of the Hawaiian Islands.

  6. LBA-ECO ND-02 Secondary Forest Tree Heights and Diameters, Para, Brazil: 1999-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides tree diameters and heights measured from 1999 to 2005 in plots of a secondary-growth forest fertilization experiment located 6.5-km northwest...

  7. Landsat-based Phenology and Tree Ring Characterization, Eastern US Forests, 1984-2013

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides a 30-year record of Landsat TM and ETM+ derived forest phenology and the results of tree ring analyses for annual wood production and nitrogen...

  8. Forest tree improvement at Michigan State University: Past, present, and future

    Science.gov (United States)

    Paul Bloese

    2010-01-01

    The Department of Forestry at Michigan State University has engaged in forest tree improvement for more than 50 years. This paper presents a brief historical perspective on past research, the status of current projects, and outlines plans for the future.

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

    National Research Council Canada - National Science Library

    van der Heijden, G. M. F; Phillips, O. L

    2009-01-01

    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...

  10. LBA-ECO ND-02 Secondary Forest Tree Heights and Diameters, Para, Brazil: 1999-2005

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: This data set provides tree diameters and heights measured from 1999 to 2005 in plots of a secondary-growth forest fertilization experiment located 6.5-km...

  11. Tree diversity does not always improve resistance of forest ecosystems to drought.

    Science.gov (United States)

    Grossiord, Charlotte; Granier, André; Ratcliffe, Sophia; Bouriaud, Olivier; Bruelheide, Helge; Chećko, Ewa; Forrester, David Ian; Dawud, Seid Muhie; Finér, Leena; Pollastrini, Martina; Scherer-Lorenzen, Michael; Valladares, Fernando; Bonal, Damien; Gessler, Arthur

    2014-10-14

    Climate models predict an increase in the intensity and frequency of drought episodes in the Northern Hemisphere. Among terrestrial ecosystems, forests will be profoundly impacted by drier climatic conditions, with drastic consequences for the functions and services they supply. Simultaneously, biodiversity is known to support a wide range of forest ecosystem functions and services. However, whether biodiversity also improves the resistance of these ecosystems to drought remains unclear. We compared soil drought exposure levels in a total of 160 forest stands within five major forest types across Europe along a gradient of tree species diversity. We assessed soil drought exposure in each forest stand by calculating the stand-level increase in carbon isotope composition of late wood from a wet to a dry year (Δδ(13)CS). Δδ(13)CS exhibited a negative linear relationship with tree species diversity in two forest types, suggesting that species interactions in these forests diminished the drought exposure of the ecosystem. However, the other three forest types were unaffected by tree species diversity. We conclude that higher diversity enhances resistance to drought events only in drought-prone environments. Managing forest ecosystems for high tree species diversity does not necessarily assure improved adaptability to the more severe and frequent drought events predicted for the future.

  12. Preparing emission reporting from forests : use of National Forest Inventories in European countries

    OpenAIRE

    Cienciala, Emil; Tomppo, Erkki; Snorrason, Arnor; Broadmeadow, Mark; Colin, Antoine; Dunger, Karsten; Exnerova, Zuzana; Lasserre, Bruno; Petersson, Hans; Priwitzer, Tibor; Sanchez Peña, Gerardo; Ståhl, Göran

    2008-01-01

    We examine the current status of greenhouse gas inventories of the sector Land Use, Land-Use Change and Forestry (LULUCF), in European countries, with specific focus on the utilization of National Forest Inventory (NFI) programs. LULUCF inventory is an integral part of the reporting obligations under the United Nations Framework Convention on Climate Change (UNFCCC) and its Kyoto Protocol. The analysis is based on two questionnaires prepared by the COST Action E43 “Harmonisation of National F...

  13. iTree-Hydro: Snow hydrology update for the urban forest hydrology model

    Science.gov (United States)

    Yang Yang; Theodore A. Endreny; David J. Nowak

    2011-01-01

    This article presents snow hydrology updates made to iTree-Hydro, previously called the Urban Forest Effects—Hydrology model. iTree-Hydro Version 1 was a warm climate model developed by the USDA Forest Service to provide a process-based planning tool with robust water quantity and quality predictions given data limitations common to most urban areas. Cold climate...

  14. Predicting climate change extirpation risk for central and southern Appalachian forest tree species

    Science.gov (United States)

    Kevin M. Potter; William W. Hargrove; Frank H. Koch

    2010-01-01

    Climate change will likely pose a severe threat to the viability of certain forest tree species, which will be forced either to adapt to new conditions or to shift to more favorable environments if they are to survive. Several forest tree species of the central and southern Appalachians may be at particular risk, since they occur in limited high-elevation ranges and/or...

  15. Climate Change Impairs Nitrogen Cycling in European Beech Forests.

    Science.gov (United States)

    Dannenmann, Michael; Bimüller, Carolin; Gschwendtner, Silvia; Leberecht, Martin; Tejedor, Javier; Bilela, Silvija; Gasche, Rainer; Hanewinkel, Marc; Baltensweiler, Andri; Kögel-Knabner, Ingrid; Polle, Andrea; Schloter, Michael; Simon, Judy; Rennenberg, Heinz

    2016-01-01

    European beech forests growing on marginal calcareous soils have been proposed to be vulnerable to decreased soil water availability. This could result in a large-scale loss of ecological services and economical value in a changing climate. In order to evaluate the potential consequences of this drought-sensitivity, we investigated potential species range shifts for European beech forests on calcareous soil in the 21st century by statistical species range distribution modelling for present day and projected future climate conditions. We found a dramatic decline by 78% until 2080. Still the physiological or biogeochemical mechanisms underlying the drought sensitivity of European beech are largely unknown. Drought sensitivity of beech is commonly attributed to plant physiological constraints. Furthermore, it has also been proposed that reduced soil water availability could promote nitrogen (N) limitation of European beech due to impaired microbial N cycling in soil, but this hypothesis has not yet been tested. Hence we investigated the influence of simulated climate change (increased temperatures, reduced soil water availability) on soil gross microbial N turnover and plant N uptake in the beech-soil interface of a typical mountainous beech forest stocking on calcareous soil in SW Germany. For this purpose, triple 15N isotope labelling of intact beech seedling-soil-microbe systems was combined with a space-for-time climate change experiment. We found that nitrate was the dominant N source for beech natural regeneration. Reduced soil water content caused a persistent decline of ammonia oxidizing bacteria and therefore, a massive attenuation of gross nitrification rates and nitrate availability in the soil. Consequently, nitrate and total N uptake of beech seedlings were strongly reduced so that impaired growth of beech seedlings was observed already after one year of exposure to simulated climatic change. We conclude that the N cycle in this ecosystem and here

  16. Human impacts affect tree community features of 20 forest fragments of a vanishing neotropical hotspot.

    Science.gov (United States)

    Pereira, José Aldo Alves; de Oliveira-Filho, Ary Teixeira; Eisenlohr, Pedro V; Miranda, Pedro L S; de Lemos Filho, José Pires

    2015-02-01

    The loss in forest area due to human occupancy is not the only threat to the remaining biodiversity: forest fragments are susceptible to additional human impact. Our aim was to investigate the effect of human impact on tree community features (species composition and abundance, and structural descriptors) and check if there was a decrease in the number of slender trees, an increase in the amount of large trees, and also a reduction in the number of tree species that occur in 20 fragments of Atlantic montane semideciduous forest in southeastern Brazil. We produced digital maps of each forest fragment using Landsat 7 satellite images and processed the maps to obtain morphometric variables. We used investigative questionnaires and field observations to survey the history of human impact. We then converted the information into scores given to the extent, severity, and duration of each impact, including proportional border area, fire, trails, coppicing, logging, and cattle, and converted these scores into categorical levels. We used linear models to assess the effect of impacts on tree species abundance distribution and stand structural descriptors. Part of the variation in floristic patterns was significantly correlated to the impacts of fire, logging, and proportional border area. Structural descriptors were influenced by cattle and outer roads. Our results provided, for the first time, strong evidence that tree species occurrence and abundance, and forest structure of Atlantic seasonal forest fragments respond differently to various modes of disturbance by humans.

  17. Genome sequence and genetic diversity of European ash trees

    DEFF Research Database (Denmark)

    Sollars, Elizabeth S A; Harper, Andrea L; Kelly, Laura J

    2017-01-01

    Ash trees (genus Fraxinus, family Oleaceae) are widespread throughout the Northern Hemisphere, but are being devastated in Europe by the fungus Hymenoscyphus fraxineus, causing ash dieback, and in North America by the herbivorous beetle Agrilus planipennis. Here we sequence the genome of a low......-heterozygosity Fraxinus excelsior tree from Gloucestershire, UK, annotating 38,852 protein-coding genes of which 25% appear ash specific when compared with the genomes of ten other plant species. Analyses of paralogous genes suggest a whole-genome duplication shared with olive (Olea europaea, Oleaceae). We also re......-sequence 37 F. excelsior trees from Europe, finding evidence for apparent long-term decline in effective population size. Using our reference sequence, we re-analyse association transcriptomic data, yielding improved markers for reduced susceptibility to ash dieback. Surveys of these markers in British...

  18. Planting sentinel European trees in eastern Asia as a novel method to identify potential insect pest invaders.

    Directory of Open Access Journals (Sweden)

    Alain Roques

    Full Text Available Quarantine measures to prevent insect invasions tend to focus on well-known pests but a large proportion of the recent invaders were not known to cause significant damage in their native range, or were not even known to science before their introduction. A novel method is proposed to detect new potential pests of woody plants in their region of origin before they are introduced to a new continent. Since Asia is currently considered to be the main supplier of insect invaders to Europe, sentinel trees were planted in China during 2007-2011 as an early warning tool to identify the potential for additional Asian insect species to colonize European trees. Seedlings (1-1.5 m tall of five broadleaved (Quercus petraea, Q. suber, Q. ilex, Fagus sylvatica, and Carpinus betulus and two conifer species (Abies alba and Cupressus sempervirens were planted in blocks of 100 seedlings at two widely separated sites (one in a nursery near Beijing and the other in a forest environment near Fuyang in eastern China, and then regularly surveyed for colonization by insects. A total of 104 insect species, mostly defoliators, were observed on these new hosts, and at least six species were capable of larval development. Although a number of the insects observed were probably incidental feeders, 38 species had more than five colonization events, mostly infesting Q. petraea, and could be considered as being capable of switching to European trees if introduced to Europe. Three years was shown to be an appropriate duration for the experiment, since the rate of colonization then tended to plateau. A majority of the identified species appeared to have switched from agricultural crops and fruit trees rather than from forest trees. Although these results are promising, the method is not appropriate for xylophagous pests and other groups developing on larger trees. Apart from the logistical problems, the identification to species level of the specimens collected was a major

  19. Planting Sentinel European Trees in Eastern Asia as a Novel Method to Identify Potential Insect Pest Invaders

    Science.gov (United States)

    Roques, Alain; Fan, Jian-ting; Courtial, Béatrice; Zhang, Yan-zhuo; Yart, Annie; Auger-Rozenberg, Marie-Anne; Denux, Olivier; Kenis, Marc; Baker, Richard; Sun, Jiang-hua

    2015-01-01

    Quarantine measures to prevent insect invasions tend to focus on well-known pests but a large proportion of the recent invaders were not known to cause significant damage in their native range, or were not even known to science before their introduction. A novel method is proposed to detect new potential pests of woody plants in their region of origin before they are introduced to a new continent. Since Asia is currently considered to be the main supplier of insect invaders to Europe, sentinel trees were planted in China during 2007-2011 as an early warning tool to identify the potential for additional Asian insect species to colonize European trees. Seedlings (1-1.5 m tall) of five broadleaved (Quercus petraea, Q. suber, Q. ilex, Fagus sylvatica, and Carpinus betulus) and two conifer species (Abies alba and Cupressus sempervirens) were planted in blocks of 100 seedlings at two widely separated sites (one in a nursery near Beijing and the other in a forest environment near Fuyang in eastern China), and then regularly surveyed for colonization by insects. A total of 104 insect species, mostly defoliators, were observed on these new hosts, and at least six species were capable of larval development. Although a number of the insects observed were probably incidental feeders, 38 species had more than five colonization events, mostly infesting Q. petraea, and could be considered as being capable of switching to European trees if introduced to Europe. Three years was shown to be an appropriate duration for the experiment, since the rate of colonization then tended to plateau. A majority of the identified species appeared to have switched from agricultural crops and fruit trees rather than from forest trees. Although these results are promising, the method is not appropriate for xylophagous pests and other groups developing on larger trees. Apart from the logistical problems, the identification to species level of the specimens collected was a major difficulty. This

  20. Trends in Spring Phenology of Western European Deciduous Forests

    Directory of Open Access Journals (Sweden)

    Eliakim Hamunyela

    2013-11-01

    Full Text Available Plant phenology is changing because of recent global warming, and this change may precipitate changes in animal distribution (e.g., pests, alter the synchronization between species, and have feedback effects on the climate system through the alteration of biogeochemical and physical processes of vegetated land surface. Here, ground observations (leaf unfolding/first leaf separation of six deciduous tree species and satellite-derived start-of-growing season (SOS are used to assess how the timing of leafing/SOS in Western European deciduous forest responded to climate variability between 2001 and 2011 and evaluate the reliability of satellite SOS estimates in tracking the response of forest leafing to climate variability in this area. Satellite SOS estimates are derived from the Normalized Difference Vegetation Index (NDVI time series of the Moderate Resolution Imaging Spectroradiometer (MODIS. Temporal trends in the SOS are quantified using linear regression, expressing SOS as a function of time. We demonstrated that the growing season was starting earlier between 2001 and 2011 for the majority of temperate deciduous forests in Western Europe, possibly influenced by regional spring warming effects experienced during the same period. A significant shift of up to 3 weeks to early leafing was found in both ground observations and satellite SOS estimates. We also show that the magnitude and trajectory of shifts in satellite SOS estimates are well comparable to that of in situ observations, hence highlighting the importance of satellite imagery in monitoring leaf phenology under a changing climate.

  1. Facilitation between woody and herbaceous plants that associate with arbuscular mycorrhizal fungi in temperate European forests.

    Science.gov (United States)

    Veresoglou, Stavros D; Wulf, Monika; Rillig, Matthias C

    2017-02-01

    In late-successional environments, low in available nutrient such as the forest understory, herbaceous plant individuals depend strongly on their mycorrhizal associates for survival. We tested whether in temperate European forests arbuscular mycorrhizal (AM) woody plants might facilitate the establishment of AM herbaceous plants in agreement with the mycorrhizal mediation hypothesis. We used a dataset spanning over 400 vegetation plots in the Weser-Elbe region (northwest Germany). Mycorrhizal status information was obtained from published resources, and Ellenberg indicator values were used to infer environmental data. We carried out tests for both relative richness and relative abundance of herbaceous plants. We found that the subset of herbaceous individuals that associated with AM profited when there was a high cover of AM woody plants. These relationships were retained when we accounted for environmental filtering effects using path analysis. Our findings build on the existing literature highlighting the prominent role of mycorrhiza as a coexistence mechanism in plant communities. From a nature conservation point of view, it may be possible to promote functional diversity in the forest understory through introducing AM woody trees in stands when absent.

  2. Trees and light : tree development and morphology in relation to light availability in a tropical rain forest in French Guiana

    NARCIS (Netherlands)

    Sterck, F.J.

    1997-01-01

    Tropical rain forest trees spend their life in a heterogeneous light environment. During their life history, they may change their growth in relation to different levels of light availability. Some of their physiological processes (e.g. photosynthesis, carbon allocation, and meristern

  3. Edge-related loss of tree phylogenetic diversity in the severely fragmented Brazilian Atlantic forest.

    Directory of Open Access Journals (Sweden)

    Bráulio A Santos

    Full Text Available Deforestation and forest fragmentation are known major causes of nonrandom extinction, but there is no information about their impact on the phylogenetic diversity of the remaining species assemblages. Using a large vegetation dataset from an old hyper-fragmented landscape in the Brazilian Atlantic rainforest we assess whether the local extirpation of tree species and functional impoverishment of tree assemblages reduce the phylogenetic diversity of the remaining tree assemblages. We detected a significant loss of tree phylogenetic diversity in forest edges, but not in core areas of small (<80 ha forest fragments. This was attributed to a reduction of 11% in the average phylogenetic distance between any two randomly chosen individuals from forest edges; an increase of 17% in the average phylogenetic distance to closest non-conspecific relative for each individual in forest edges; and to the potential manifestation of late edge effects in the core areas of small forest remnants. We found no evidence supporting fragmentation-induced phylogenetic clustering or evenness. This could be explained by the low phylogenetic conservatism of key life-history traits corresponding to vulnerable species. Edge effects must be reduced to effectively protect tree phylogenetic diversity in the severely fragmented Brazilian Atlantic forest.

  4. 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

  5. Effects of tree species on soil properties in a forest of the Northeastern United States

    NARCIS (Netherlands)

    Dijkstra, F.A.

    2001-01-01

    Large differences in soil pH and available Ca in the surface soil exist among tree species growing in a mixed hardwood forest in northwestern Connecticut. The observed association between tree species and specific soil chemical properties within mixed-species stands implies that changes in

  6. Calcium weathering in forested soils and the effedt of different tree species

    NARCIS (Netherlands)

    Dijkstra, F.A.; Breemen, van N.; Jongmans, A.G.; Davies, G.R.; Likens, G.E.

    2003-01-01

    Soil weathering can be an important mechanism to neutralize acidity in forest soils. Tree species may differ in their effect on or response to soil weathering. We used soil mineral data and the natural strontium isotope ratio Sr-87/Sr-86 as a tracer to identify the effect of tree species on the Ca

  7. Long-term drought sensitivity of trees in second-growth forests in a humid region

    Science.gov (United States)

    Neil Pederson; Kacie Tackett; Ryan W. McEwan; Stacy Clark; Adrienne Cooper; Glade Brosi; Ray Eaton; R. Drew Stockwell

    2012-01-01

    Classical field methods of reconstructing drought using tree rings in humid, temperate regions typically target old trees from drought-prone sites. This approach limits investigators to a handful of species and excludes large amounts of data that might be useful, especially for coverage gaps in large-scale networks. By sampling in more “typical” forests, network...

  8. Summer droughts limit tree growth across 10 temperate species on a productive forest site

    NARCIS (Netherlands)

    Weemstra, M.; Eilmann, B.; Sass-Klaassen, U.; Sterck, F.J.

    2013-01-01

    Studies on climate impacts on tree annual growth are mainly restricted to marginal sites. To date, the climate effects on annual growth of trees in favorable environments remain therefore unclear despite the importance of these sites in terms of forest productivity. Because species respond

  9. 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...

  10. Effect of tree species and soil properties on nutrient immobilization in the forest floor

    DEFF Research Database (Denmark)

    Raulund-Rasmussen, Karsten; Vejre, Henrik

    1995-01-01

    To investigate the effect of tree species and soil properties on organic matter accumulation and associated nutrients, an area-based sampling of the forest floor was carried out in a 28 years old species trial including Norway spruce, Douglas fir, beech, and common oak at two sites, a poor...... IMMOBILIZATION; SOIL PROPERTIES; SOIL SOLUTION; TREE SPECIES...

  11. Proceedings of the 12th Lake States Forest Tree Improvement Conference, August 1975.

    Science.gov (United States)

    USDA FS

    1976-01-01

    Presents 20 papers concerning recent research in forest genetics, physiology, and allied fields. Species discussed include cottonwood, white spruce, jack pine, white pine, aspen, and others. Emphasizes the role of tree improvement in increasing wood-fiber production. Includes abstracts from papers presented at the 15th Canadian Tree Improvement Association Meeting...

  12. Comparing i-Tree modeled ozone deposition with field measurements in a periurban Mediterranean forest

    Science.gov (United States)

    A. Morani; D. Nowak; S. Hirabayashi; G. Guidolotti; M. Medori; V. Muzzini; S. Fares; G. Scarascia Mugnozza; C. Calfapietra

    2014-01-01

    Ozone flux estimates from the i-Tree model were compared with ozone flux measurements using the Eddy Covariance technique in a periurban Mediterranean forest near Rome (Castelporziano). For the first time i-Tree model outputs were compared with field measurements in relation to dry deposition estimates. Results showed generally a...

  13. Understanding the Roles of Forests and Tree-based Systems in Food Provision

    NARCIS (Netherlands)

    Jamnadass, R.; McMullin, S.; Dawson, M.I.I.K.; Powell, B.; Termote, C.; Lckowitz, A.; Kehlenbeck, K.; Vinceti, B.; Vliet, van N.; Keding, G.; Stadlmayr, B.; Damme, van P.; Carsan, S.; Sunderland, T.; Njenga, M.; Gyau, A.; Cerutti, P.; Schure, J.M.; Kouame, C.; Obiri, B.D.; Ofori, D.; Agarwal, B.; Neufeldt, H.; Degrande, A.; Serban, A.

    2015-01-01

    Forests and other tree-based systems such as agroforestry contribute to food and nutritional security in myriad ways. Directly, trees provide a variety of healthy foods including fruits, leafy vegetables, nuts, seeds and edible oils that can diversify diets and address seasonal food and nutritional

  14. Prescribed fire effects on bark beetle activity and tree mortality in southwestern ponderosa pine forests

    Science.gov (United States)

    C.R. Breece; T.E. Kolb; B.G. Dickson; J.D. McMillin; K.M. Clancey

    2008-01-01

    Prescribed fire is an important tool in the management of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) forests, yet effects on bark beetle (Coleoptera: Curculionidae, Scolytinae) activity and tree mortality are poorly understood in the southwestern U.S. We compared bark beetle attacks and tree mortality between paired prescribed-burned and...

  15. Building the Forest Inventory and Analysis Tree-Ring Data set

    Science.gov (United States)

    Robert J. DeRose; John D. Shaw; James N. Long

    2017-01-01

    The Interior West Forest Inventory and Analysis (IW-FIA) program measures forestland conditions at great extent with relatively high spatial resolution, including the collection of tree-ring data. We describe the development of an unprecedented spatial tree-ring data set for the IW-FIA that enhances the baseline plot data by incorporating ring-width increment measured...

  16. Banking on the future: progress, challenges and opportunities for the genetic conservation of forest trees

    Science.gov (United States)

    Kevin M. Potter; Robert M. Jetton; Andrew Bower; Douglass F. Jacobs; Gary Man; Valerie D. Hipkins; Murphy Westwood

    2017-01-01

    Genetic diversity provides the essential basis for the adaptation and resilience of tree species to environmental stress and change. The genetic conservation of tree species is an urgent global necessity as forest conversion and fragmentation continue apace, damaging insects and pathogens are transported between continents, and climate change alters local habitat...

  17. Topographic frequency of trees in the tabonuco forest of the Luquillo Mountains

    Science.gov (United States)

    Frank H. Wadsworth

    2009-01-01

    A previous study of tree productivity in the subtropical wet forest of the Luquillo Mountains of Puerto Rico was used to expose the frequency of 12 timber tree species to six different topographic sites, convex versus concave surface, lower versus upper slopes, and windward versus leeward aspects. All but one of the species are found in all six locations and the...

  18. Contribution to the knowledge of woods preferences of European beaver (Castor fiber L. 1758 in bank vegetation on non-forest land in the forest district Soutok (Czech Republic

    Directory of Open Access Journals (Sweden)

    Jakub Urban

    2008-01-01

    Full Text Available From 2003 to 2005, this work studied the preference of tree species on non-forest land in the forest district Soutok (Southern Moravia, Czech Republic in order to evaluate the suitability of the area for the development and the its importance in relation to the decrease of damage in neighbouring production forests. The diet included the total of 14 tree species with diameter interval reaching from 1–10 cm to 191–200 cm. The most preferred species was Common Ash (Fraxinus excelsior (40.5 % with the diameter 1–10 cm and willow (Salix spp. (31.7 % with the diameter 11–20 cm – both species with good ability to regenerate. Activities of European beaver negatively influenced the population of European white elm (Ulmus laevis, which belongs to the endangered species. Significant is the low ratio of poplars Populus spp. (7.9 % caused by the forest management. Maintaining the suitable tree composition and a sufficiently high percentage of individual tree species – in favour of willows and poplars – can result in the needed decrease of stress caused by the population of beaver on the adjacent forest stands and in the decrease of possible damage.

  19. Mapping pyrophilic percentages across the northeastern United States using witness trees, with focus on four national forests

    Science.gov (United States)

    Melissa A. Thomas-Van Gundy; Gregory J. Nowacki; Charles V. Cogbill

    2015-01-01

    Witness trees provide information fundamental for restoration ecology, often serving as baselines for forest composition and structure. Furthermore, when categorized by fire relations, witness trees can shed light on past disturbance regimes. Kriging was applied to witness-tree point data to form a contiguous surface of pyrophilic percentage for four national forests...

  20. Recent changes in the estimation of standing dead tree biomass and carbon stocks in the U.S. forest inventory

    Science.gov (United States)

    Grant M. Domke; Christopher W. Woodall; James E. Smith

    2012-01-01

    Until recently, standing dead tree biomass and carbon (C) has been estimated as a function of live tree growing stock volume in the U.S. Forest Service, Forest Inventory and Analysis (FIA) Program. Traditional estimates of standing dead tree biomass/C attributes were based on merchantability standards that did not reflect density reductions or structural loss due to...

  1. Analyzing the uncertainties in use of forest-derived biomass equations for open-grown trees in agricultural land

    Science.gov (United States)

    Xinhua Zhou; Michele M. Schoeneberger; James R. Brandle; Tala N. Awada; Jianmin Chu; Derrel L. Martin; Jihong Li; Yuqiang Li; Carl W. Mize

    2014-01-01

    Quantifying carbon in agroforestry trees requires biomass equations that capture the growth differences (e.g., tree specific gravity and architecture) created in the more open canopies of agroforestry plantings compared with those generally encountered in forests. Whereas forest-derived equations are available, equations for open-grown trees are not. Data from...

  2. Biomechanical effects of trees in a mountain temperate forest: implications for biogeomorphology, soil science, and forest dynamics

    Science.gov (United States)

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

    2017-04-01

    Biomechanical effects of trees in forest soils represent a potentially significant factor in hillslope processes, pedocomplexity, and forest dynamics. However, these processes have been only rarely studied so far. Within this study we aim (i) to elaborate a detailed and widely applicable methodology of quantification of the main biomechanical effects of trees in soil, (ii) to reveal actual (minimal) frequencies, areas and volumes related to these effects in a mountain temperate old-growth forest. The research took place in the Boubín Primeval Forest in the Czech Republic. The fir-spruce-beech forest reserve belongs among the oldest protected areas in Europe. The reserve occupies NE slopes of an average inclination of about 14˚ on gneiss at an altitude of 930-1110 m a.s.l. We evaluated effects of all standing or lying trees of diameter at breast height (DBH) ≥ 10 cm in an area of 10.2 ha. In total, 4000 trees were studied from viewpoint of following features: treethrow, root mound, bioprotective function of standing as well as lying tree, baumstein, root baumstein, infilling stump, hole after trunk fall, stemwash, trunkwash. Any biomechanical phenomena were recorded in 59% of standing and 51% of lying dead trees (excluding the pervasive soil displacement by thickening trunk and roots and the converse infilling of the space freed during their decay with surrounding soil). Approximately one tenth of the trees expressed simultaneously opposing phenomena such as blocking of slope processes and their intensification. Different tree species and DBH categories exhibited significantly different structure of biomechanical effects in soil. Bioprotective function represented the most frequent process. However, concerning area and volume of affected soil, treethrows were an even more important phenomenon. Total area influenced by the studied biomechanical effects of current generation of trees was 343 m2ha-1. Additional 774 m2ha-1 were occupied by older treethrow pit

  3. Variability in early height growth rate of forest trees: implications for retrospective studies of stand dynamics

    Science.gov (United States)

    Brain J. Palik; Kurt S. Pregitzer

    1995-01-01

    Retrospective studies of forest stand dynamics may rely on estimates of tree ages. In some of these studies, trees are aged near the stem base, while in other studies trees may be aged at breast height. An age correction may be added to breast-height ages in an attempt to account for average time to reach breast height and thus provide better estimates of total ages....

  4. Responses of bark beetle (Coleoptera: Curculionidae: Scolytinae community structure to green-tree retention in pine tree forest from Korea

    Directory of Open Access Journals (Sweden)

    Da-Som Kim

    2016-12-01

    Full Text Available This study was aimed to investigate the response of bark beetle community structure to green-tree retention in a Korean pine tree forest between 2013 and 2015. Five types of retention methods were evaluated to investigate the retention effect on insect community structure at various sites in Keunjeogol, Samcheok, and Gangwon-do. Lindgren funnel traps were installed to collect insects from July to August, over a 3-year period. Overall, 690 individuals and 29 species of Scolytinae were collected, with populations of insects appearing to gradually increase by each year of the study. Results of the insect community analysis showed that most survey sites presented a higher diversity than the control site annually except in 2015. This study can be used as a baseline dataset for the long-term study of early changes in insect community in response to green-tree retention in forests.

  5. Effects of dust on forest tree health in Zagros oak forests.

    Science.gov (United States)

    Moradi, A; Taheri Abkenar, K; Afshar Mohammadian, M; Shabanian, N

    2017-10-10

    Dust is one of the most devastating factors for the environment threatening all animal and plant species. In many regions, the ecological and economic impact of microdust on scarce species is critical. In the western region of Iran, the Zagros forests have been exposed to dust storms for many years. In this study, the effect of dust on oak trees, the most important trees of Zagros forests, is investigated. For this purpose, 3-year-old seedlings of three species of oak trees under natural conditions were exposed to dust during spring and summer months. Seedlings were divided into two groups; one group was assigned as dust treatment and the other as control that the control group washed regularly to remove dust. Anatomical characteristics of leaves and dust deposits on leaves during the study period were examined by scanning electron microscope (SEM). The rate of photosynthesis and gas exchange in control and treated plants was examined by IRGA, LCI. SEM images showed that stomata structure, trichome density, and epicuticular waxes of leaves are different in all three species. This difference in micromorphology of species influences the effects of dust deposited on the leaves. A comparison of leaf species images in control and dust treatment showed that in dust treatment the percentage of stomata blocked by dust in three species (per unit area) of Quercus infectoria, Q. libni, and Q. brantii were 61/6, 48/4, and 38/1%, respectively. The results of leaf gas exchange investigation indicated that stomatal occlusion by dust had a negative impact on the examined parameters of three oak species (P ≤ 0.01). Thus, gas exchange and photosynthetic rates of the treated species were significantly reduced. The results of both parts of the study showed the vulnerability of the three species to dust as Q. infectoria > Q. libni > Q. brantii. Therefore, based on these findings, dust can disrupt the physiological activities of the studied species and the continuation of the

  6. Genome sequence and genetic diversity of European ash trees.

    Science.gov (United States)

    Sollars, Elizabeth S A; Harper, Andrea L; Kelly, Laura J; Sambles, Christine M; Ramirez-Gonzalez, Ricardo H; Swarbreck, David; Kaithakottil, Gemy; Cooper, Endymion D; Uauy, Cristobal; Havlickova, Lenka; Worswick, Gemma; Studholme, David J; Zohren, Jasmin; Salmon, Deborah L; Clavijo, Bernardo J; Li, Yi; He, Zhesi; Fellgett, Alison; McKinney, Lea Vig; Nielsen, Lene Rostgaard; Douglas, Gerry C; Kjær, Erik Dahl; Downie, J Allan; Boshier, David; Lee, Steve; Clark, Jo; Grant, Murray; Bancroft, Ian; Caccamo, Mario; Buggs, Richard J A

    2017-01-12

    Ash trees (genus Fraxinus, family Oleaceae) are widespread throughout the Northern Hemisphere, but are being devastated in Europe by the fungus Hymenoscyphus fraxineus, causing ash dieback, and in North America by the herbivorous beetle Agrilus planipennis. Here we sequence the genome of a low-heterozygosity Fraxinus excelsior tree from Gloucestershire, UK, annotating 38,852 protein-coding genes of which 25% appear ash specific when compared with the genomes of ten other plant species. Analyses of paralogous genes suggest a whole-genome duplication shared with olive (Olea europaea, Oleaceae). We also re-sequence 37 F. excelsior trees from Europe, finding evidence for apparent long-term decline in effective population size. Using our reference sequence, we re-analyse association transcriptomic data, yielding improved markers for reduced susceptibility to ash dieback. Surveys of these markers in British populations suggest that reduced susceptibility to ash dieback may be more widespread in Great Britain than in Denmark. We also present evidence that susceptibility of trees to H. fraxineus is associated with their iridoid glycoside levels. This rapid, integrated, multidisciplinary research response to an emerging health threat in a non-model organism opens the way for mitigation of the epidemic.

  7. An object-oriented forest landscape model and its representation of tree species

    Science.gov (United States)

    Hong S. He; David J. Mladenoff; Joel Boeder

    1999-01-01

    LANDIS is a forest landscape model that simulates the interaction of large landscape processes and forest successional dynamics at tree species level. We discuss how object-oriented design (OOD) approaches such as modularity, abstraction and encapsulation are integrated into the design of LANDIS. We show that using OOD approaches, model decisions (olden as model...

  8. Evidence that soil aluminum enforces site fidelity of southern New England forest trees

    Science.gov (United States)

    S. W. Bigelow; C. D. Canham

    2010-01-01

    Tree species composition of hardwood forests of the northeastern United States corresponds with soil chemistry, and differential performance along soil calcium (Ca) gradients has been proposed as a mechanism for enforcing this fidelity of species to site. We conducted studies in a southern New England forest to test if surface-soil Ca is more important than other...

  9. Observations on the fauna that visit African Tulip Tree (Spathodea campanulata Beauv.) forests in Puerto Rico

    Science.gov (United States)

    Oscar J. Abelleira Martinez

    2008-01-01

    Diurnal field observations in secondary forests dominated by the introduced African tulip tree (Spathodea campanulata) in Puerto Rico show a faunal assemblage that consists mostly of native species (81.1 percent). The most abundant species were common birds and reptiles, yet some uncommon fauna appear to be visiting or residing in these forests. The observations...

  10. Allometric equations for estimating tree biomass in restored mixed-species Atlantic Forest stands

    Science.gov (United States)

    Lauro Rodrigues Nogueira; Vera Lex Engel; John A. Parrotta; Antonio Carlos Galvão de Melo; Danilo. Scorzoni Ré

    2014-01-01

    Restoration of Atlantic Forests is receiving increasing attention because of its role in both biodiversity conservation and carbon sequestration for global climate change mitigation. This study was carried out in an Atlantic Forest restoration project in the south-central region of São Paulo State – Brazil to develop allometric equations to estimate tree biomass of...

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

    Science.gov (United States)

    Joseph L. Ganey; Scott C. Vojta

    2011-01-01

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

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

    Science.gov (United States)

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

    2017-01-01

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

  13. Diversity, stand characteristics and spatial aggregation of tree species in a Bangladesh forest ecosystem

    DEFF Research Database (Denmark)

    Uddin, Mohammad B.; Steinbauer, Manuel; Beierkuhnlein, Carl

    2011-01-01

    Assessing biodiversity and the spatial structures of forest ecosystems are important for forestry and nature conservation. However, tropical forests of Bangladesh are only sparsely investigated. Here we determined biodiversity (alpha, beta and gamma), spatial species turnover and stand characteri......Assessing biodiversity and the spatial structures of forest ecosystems are important for forestry and nature conservation. However, tropical forests of Bangladesh are only sparsely investigated. Here we determined biodiversity (alpha, beta and gamma), spatial species turnover and stand...... characteristics of one of the few remnant tropical forests in Bangladesh. Two differently protected areas of Satchari forest were compared. We recorded tree species composition, in a systematic plot design, measured diameter at breast height for each individual tree (to assess basal area), and calculated decay...

  14. Effect of different tree mortality patterns on stand development in the forest model SIBYLA

    Directory of Open Access Journals (Sweden)

    Trombik Jiří

    2016-09-01

    Full Text Available Forest mortality critically affects stand structure and the quality of ecosystem services provided by forests. Spruce bark beetle (Ips typographus generates rather complex infestation and mortality patterns, and implementation of such patterns in forest models is challenging. We present here the procedure, which allows to simulate the bark beetle-related tree mortality in the forest dynamics model Sibyla. We explored how sensitive various production and stand structure indicators are to tree mortality patterns, which can be generated by bark beetles. We compared the simulation outputs for three unmanaged forest stands with 40, 70 and 100% proportion of spruce as affected by the disturbance-related mortality that occurred in a random pattern and in a patchy pattern. The used tree species and age class-specific mortality rates were derived from the disturbance-related mortality records from Slovakia. The proposed algorithm was developed in the SQLite using the Python language, and the algorithm allowed us to define the degree of spatial clustering of dead trees ranging from a random distribution to a completely clustered distribution; a number of trees that died in either mode is set to remain equal. We found significant differences between the long-term developments of the three investigated forest stands, but we found very little effect of the tested mortality modes on stand increment, tree species composition and diversity, and tree size diversity. Hence, our hypothesis that the different pattern of dead trees emergence should affect the competitive interactions between trees and regeneration, and thus affect selected productivity and stand structure indicators was not confirmed.

  15. Unmanned aerial survey of fallen trees in a deciduous broadleaved forest in eastern Japan.

    Science.gov (United States)

    Inoue, Tomoharu; Nagai, Shin; Yamashita, Satoshi; Fadaei, Hadi; Ishii, Reiichiro; Okabe, Kimiko; Taki, Hisatomo; Honda, Yoshiaki; Kajiwara, Koji; Suzuki, Rikie

    2014-01-01

    Since fallen trees are a key factor in biodiversity and biogeochemical cycling, information about their spatial distribution is of use in determining species distribution and nutrient and carbon cycling in forest ecosystems. Ground-based surveys are both time consuming and labour intensive. Remote-sensing technology can reduce these costs. Here, we used high-spatial-resolution aerial photographs (0.5-1.0 cm per pixel) taken from an unmanned aerial vehicle (UAV) to survey fallen trees in a deciduous broadleaved forest in eastern Japan. In nine sub-plots we found a total of 44 fallen trees by ground survey. From the aerial photographs, we identified 80% to 90% of fallen trees that were >30 cm in diameter or >10 m in length, but missed many that were narrower or shorter. This failure may be due to the similarity of fallen trees to trunks and branches of standing trees or masking by standing trees. Views of the same point from different angles may improve the detection rate because they would provide more opportunity to detect fallen trees hidden by standing trees. Our results suggest that UAV surveys will make it possible to monitor the spatial and temporal variations in forest structure and function at lower cost.

  16. Composition, complexity, and tree mortality in riparian forests in the central Western Cascades of Oregon

    Science.gov (United States)

    Acker, Steve A.; Gregory, S.V.; Lienkaemper, G.; McKee, W.A.; Swanson, F.J.; Miller, S.D.

    2003-01-01

    Riparian forests contribute to the diversity and function of both terrestrial and aquatic ecosystems. To assess some of these contributions, we compared tree composition, stand complexity, and temporal patterns of tree mortality on permanent plots in seven mature and old-growth stands representing upland forests and forests along low- and mid-order streams in the Western Cascade Range of Oregon. We also assessed recruitment of large wood into stream channels due to tree mortality, both by direct measurement and by estimation from tree mortality and location data. Stands differed in composition due to both stream order and successional stage. Stands on mid-order streams had high abundance of hardwood trees and/or Thuja plicata. Stand complexity (variability in tree diameters, tree life-form diversity, and tree species diversity), was high in stands on mid-order streams and in the upland, old-growth stand. Tree mortality was exceptionally high in six of the seven stands in 1996, the year in which the largest flood during the study occurred. However, only in the one stand on an unconstrained reach of a mid-order stream was mortality primarily due to flooding. Estimated recruitment of wood was much higher from the stand on the unconstrained reach than from the other stands on mid-order streams, suggesting that unconstrained reaches may be important for efforts to maintain or restore large wood in streams.

  17. How to kill a tree: empirical mortality models for 18 species and their performance in a dynamic forest model.

    Science.gov (United States)

    Hülsmann, Lisa; Bugmann, Harald; Cailleret, Maxime; Brang, Peter

    2017-12-21

    Dynamic Vegetation Models (DVMs) are designed to be suitable for simulating forest succession and species range dynamics under current and future conditions based on mathematical representations of the three key processes regeneration, growth, and mortality. However, mortality formulations in DVMs are typically coarse and often lack an empirical basis, which increases the uncertainty of projections of future forest dynamics and hinders their use for developing adaptation strategies to climate change. Thus, sound tree mortality models are highly needed. We developed parsimonious, species-specific mortality models for 18 European tree species using >90,000 records from inventories in Swiss and German strict forest reserves along a considerable environmental gradient. We comprehensively evaluated model performance and incorporated the new mortality functions in the dynamic forest model ForClim. Tree mortality was successfully predicted by tree size and growth. Only a few species required additional covariates in their final model to consider aspects of stand structure or climate. The relationships between mortality and its predictors reflect the indirect influences of resource availability and tree vitality, which are further shaped by species-specific attributes such as maximum longevity and shade tolerance. Considering that the behavior of the models was biologically meaningful, and that their performance was reasonably high and not impacted by changes in the sampling design, we suggest that the mortality algorithms developed here are suitable for implementation and evaluation in DVMs. In the DVM ForClim, the new mortality functions resulted in simulations of stand basal area and species composition that were generally close to historical observations. However, ForClim performance was poorer than when using the original, coarse mortality formulation. The difficulties of simulating stand structure and species composition, which were most evident for Fagus sylvatica L

  18. Technical guide to crop tree release in hardwood forests

    Science.gov (United States)

    Gary W. Miller; Jeffrey W. Stringer; David C. Mercker

    2007-01-01

    Crop tree release (CTR) is a widely applicable silvicultural technique used to enhance the performance of individual trees. It offers flexibility in that it can be applied on small or large properties, and with certain modifications, it can be applied as a precommercial or commercial operation. By favoring the development of selected crop trees within a hardwood stand...

  19. How liana loads alter tree allometry in tropical forests

    NARCIS (Netherlands)

    Souza Dias, de Arildo; Santos, Dos Karin; Santos, Dos Flavio Antonio Maës; Martins, Fernando R.

    2017-01-01

    Intense competition with lianas (wood climbers) can limit tree growth, reproduction, and survival. However, the negative effects of liana loads on tree allometry have not yet been addressed. We investigated the hypothesis that liana loading on tree crown alters tree’s allometry, expressed through

  20. Bark removal for medicinal use predisposes indigenous forest trees ...

    African Journals Online (AJOL)

    The injury caused to trees leads to wood deterioration as a result of insect damage and fungal infection. This study aimed to ascertain the effects of different bark harvesting practices on the quality of wood of selected indigenous tree species often used as medicinal plants. The bark of these trees, which included ...

  1. Association of trees, shrubs, and other vegetation in northern Idaho forests

    Science.gov (United States)

    J. A. Larsen

    1923-01-01

    It is the purpose of this paper to set forth the association of the most common herbs, shrubs, and trees in the forests of northern Idaho, in the hope that the information may afford a better insight into the quality and general characteristics of the habitats. The herbs and shrubs listed were collected at the Priest River Forest Experiment Station of the U. S. Forest...

  2. Evaluating management regimes for European beech forests using dynamic programming

    Directory of Open Access Journals (Sweden)

    Juan Torres Rojo

    2014-12-01

    Full Text Available Aim of study: This contribution describes a systematic search method for identifying optimum thinning regimes for beech forests (Fagus sylvatica L. by using a combination of optimization heuristics and a simple whole stand growth prediction model. Area of study: Data to build the model come from standard and management forest inventories as well as yield tables from the Northern and Western part of Germany and from southern and central Denmark.Material and Methods: Growth projections are made from equations to project basal area and top height.  The remaining stand variables are recovered from additional equations fitted from forest inventory data or acquired from other authors.  Mortality is estimated through an algorithm based on the maximum density line. The optimization routine uses a two-state dynamic programming model. Thinning type is defined by the NG index, which describes the ratio of the proportion of removed trees and basal area with respect to the same proportion  before thinning. Main results: Growth equations fitted from inventory data show high goodness of fit with R2 values larger than 0.85 and high significance levels for the parameter estimates. The mortality algorithm converges quickly providing mortality estimates within the expected range.Research Highlights: The combination of a simple growth and yield model within a Dynamic Programming framework in conjunction with NG values as indicators of thinning type yield good estimates of practical thinning schedules compared to thinning recommendations provided by diverse authors.Keywords: beech (Fagus sylvatica L.; NG ratio; thinning optimization; growth and yield simulation; mortality.

  3. Individual size but not additional nitrogen regulates tree carbon sequestration in a subtropical forest

    Science.gov (United States)

    Wu, Jianping; Duan, Honglang; Liu, Wenfei; Wei, Xiaohua; Liao, Yingchun; Fan, Houbao

    2017-04-01

    Recent studies have indicated that tree carbon accumulation in subtropical forests has been negatively affected by global change phenomena such as warming and drought. However, the long-term effect of nitrogen addition on plant carbon storage remains poorly understood in these regions. In this study, we conducted a 10-year field experiment examining the effect of experimental N addition on plant growth and carbon storage in a subtropical Chinese fir forest. The N levels were 0 (control), 60, 120, and 240 kg ha-1 yr-1, and the N effects on tree carbon were divided into stand and individual levels. The results indicated that tree carbon storage at the stand scale was not affected by long-term N addition in the subtropical forest. By contrast, significant impacts of different tree size classes on carbon sequestration were found under different N treatments, which indicated that the amount of plant carbon sequestration was significantly enhanced with tree size class. Our findings highlight the importance of community structure and growth characteristics in Chinese fir forests, in which individual size but not additional N regulates tree carbon sequestration in this subtropical forest.

  4. Allometric biomass equations for 12 tree species in coniferous and broadleaved mixed forests, Northeastern China.

    Science.gov (United States)

    He, Huaijiang; Zhang, Chunyu; Zhao, Xiuhai; Fousseni, Folega; Wang, Jinsong; Dai, Haijun; Yang, Song; Zuo, Qiang

    2018-01-01

    Understanding forest carbon budget and dynamics for sustainable resource management and ecosystem functions requires quantification of above- and below-ground biomass at individual tree species and stand levels. In this study, a total of 122 trees (9-12 per species) were destructively sampled to determine above- and below-ground biomass of 12 tree species (Acer mandshuricum, Acer mono, Betula platyphylla, Carpinus cordata, Fraxinus mandshurica, Juglans mandshurica, Maackia amurensis, P. koraiensis, Populus ussuriensis, Quercus mongolica, Tilia amurensis and Ulmus japonica) in coniferous and broadleaved mixed forests of Northeastern China, an area of the largest natural forest in the country. Biomass allocation was examined and biomass models were developed using diameter as independent variable for individual tree species and all species combined. The results showed that the largest biomass allocation of all species combined was on stems (57.1%), followed by coarse root (21.3%), branch (18.7%), and foliage (2.9%). The log-transformed model was statistically significant for all biomass components, although predicting power was higher for species-specific models than for all species combined, general biomass models, and higher for stems, roots, above-ground biomass, and total tree biomass than for branch and foliage biomass. These findings supplement the previous studies on this forest type by additional sample trees, species and locations, and support biomass research on forest carbon budget and dynamics by management activities such as thinning and harvesting in the northeastern part of China.

  5. Detailed maps of tropical forest types are within reach: forest tree communities for Trinidad and Tobago mapped with multiseason Landsat and multiseason fine-resolution imagery

    Science.gov (United States)

    Eileen H. Helmer; Thomas S. Ruzycki; Jay Benner; Shannon M. Voggesser; Barbara P. Scobie; Courtenay Park; David W. Fanning; Seepersad. Ramnarine

    2012-01-01

    Tropical forest managers need detailed maps of forest types for REDD+, but spectral similarity among forest types; cloud and scan-line gaps; and scarce vegetation ground plots make producing such maps with satellite imagery difficult. How can managers map tropical forest tree communities with satellite imagery given these challenges? Here we describe a case study of...

  6. Correspondence: Rapid tree carbon stock recovery in managed Amazonian forests

    NARCIS (Netherlands)

    Rutishauser, E.; Hérault, B.; Baraloto, C.; Blanc, L.; Descroix, L.; Sotta, E.; Ferreira, J.; Kanashiro, M.; Mazzei, L.; Pena Claros, M.

    2015-01-01

    While around 20% of the Amazonian forest has been cleared for pastures and agriculture, one fourth of the remaining forest is dedicated to wood production [1]. Most of these production forests have been or will be selectively harvested for commercial timber, but recent studies show that even soon

  7. Height-related changes in leaf photosynthetic traits in diverse Bornean tropical rain forest trees.

    Science.gov (United States)

    Kenzo, Tanaka; Inoue, Yuta; Yoshimura, Mitsunori; Yamashita, Megumi; Tanaka-Oda, Ayumi; Ichie, Tomoaki

    2015-01-01

    Knowledge of variations in morphophysiological leaf traits with forest height is essential for quantifying carbon and water fluxes from forest ecosystems. Here, we examined changes in leaf traits with forest height in diverse tree species and their role in environmental acclimation in a tropical rain forest in Borneo that does not experience dry spells. Height-related changes in leaf physiological and morphological traits [e.g., maximum photosynthetic rate (Amax), stomatal conductance (gs), dark respiration rate (Rd), carbon isotope ratio (δ(13)C), nitrogen (N) content, and leaf mass per area (LMA)] from understory to emergent trees were investigated in 104 species in 29 families. We found that many leaf area-based physiological traits (e.g., A(max-area), Rd, gs), N, δ(13)C, and LMA increased linearly with tree height, while leaf mass-based physiological traits (e.g., A(max-mass)) only increased slightly. These patterns differed from other biomes such as temperate and tropical dry forests, where trees usually show decreased photosynthetic capacity (e.g., A(max-area), A(max-mass)) with height. Increases in photosynthetic capacity, LMA, and δ(13)C are favored under bright and dry upper canopy conditions with higher photosynthetic productivity and drought tolerance, whereas lower R d and LMA may improve shade tolerance in lower canopy trees. Rapid recovery of leaf midday water potential to theoretical gravity potential during the night supports the idea that the majority of trees do not suffer from strong drought stress. Overall, leaf area-based photosynthetic traits were associated with tree height and the degree of leaf drought stress, even in diverse tropical rain forest trees.

  8. Environmental change impacts on the C- and N-cycle of European forests: a model comparison study

    Directory of Open Access Journals (Sweden)

    D. R. Cameron

    2013-03-01

    Full Text Available Forests are important components of the greenhouse gas balance of Europe. There is considerable uncertainty about how predicted changes to climate and nitrogen deposition will perturb the carbon and nitrogen cycles of European forests and thereby alter forest growth, carbon sequestration and N2O emission. The present study aimed to quantify the carbon and nitrogen balance, including the exchange of greenhouse gases, of European forests over the period 2010–2030, with a particular emphasis on the spatial variability of change. The analysis was carried out for two tree species: European beech and Scots pine. For this purpose, four different dynamic models were used: BASFOR, DailyDayCent, INTEGRATOR and Landscape-DNDC. These models span a range from semi-empirical to complex mechanistic. Comparison of these models allowed assessment of the extent to which model predictions depended on differences in model inputs and structure. We found a European average carbon sink of 0.160 ± 0.020 kgC m−2 yr−1 (pine and 0.138 ± 0.062 kgC m−2 yr−1 (beech and N2O source of 0.285 ± 0.125 kgN ha−1 yr−1 (pine and 0.575 ± 0.105 kgN ha−1 yr−1 (beech. The European average greenhouse gas potential of the carbon sink was 18 (pine and 8 (beech times that of the N2O source. Carbon sequestration was larger in the trees than in the soil. Carbon sequestration and forest growth were largest in central Europe and lowest in northern Sweden and Finland, N. Poland and S. Spain. No single driver was found to dominate change across Europe. Forests were found to be most sensitive to change in environmental drivers where the drivers were limiting growth, where changes were particularly large or where changes acted in concert. The models disagreed as to which environmental changes were most significant for the geographical variation in forest growth and as to which tree species showed the largest rate of carbon sequestration. Pine and beech forests were found to

  9. Modelling and mapping the suitability of European forest formations at 1-km resolution

    DEFF Research Database (Denmark)

    Casalegno, Stefano; Amatulli, Giuseppe; Bastrup-Birk, Annemarie

    2011-01-01

    factors. Here, we used the bootstrap-aggregating machine-learning ensemble classifier Random Forest (RF) to derive a 1-km resolution European forest formation suitability map. The statistical model use as inputs more than 6,000 field data forest inventory plots and a large set of environmental variables...

  10. EUFORGEN as an instrument for the conservation of European forest genetic resources

    NARCIS (Netherlands)

    Vries, de S.M.G.

    2006-01-01

    Following the Ministerial Conference for the Protection of Forest in Europe, held in Strasbourg in 1990, and more specifically its Resolution No. 2 concerning the conservation of forest genetic resources EUFORGEN (European Forest Genetic Resources Programme) was established. EUFORGEN is a

  11. Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest.

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Scott; Hanula, James L.; Ulyshen, Michael D.; Kilgo, John C.

    2005-01-01

    Horn, Scott, James L. Hanula, Michael D. Ulyshen, and John C. Kilgo. 2005. Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest. Am. Midl. Nat. 153:321-326. Abstract: We found more green tree frogs (Hyla cinerea) in canopy gaps than in closed canopy forest. Of the 331 green tree frogs observed, 88% were in canopy gaps. Likewise, higher numbers and biomasses of insects were captured in the open gap habitat. Flies were the most commonly collected insect group accounting for 54% of the total capture. These data suggest that one reason green tree frogs were more abundant in canopy gaps was the increased availability of prey and that small canopy gaps provide early successional habitats that are beneficial to green tree frog populations.

  12. Unique competitive effects of lianas and trees in a tropical forest understory.

    Science.gov (United States)

    Wright, Alexandra; Tobin, Mike; Mangan, Scott; Schnitzer, Stefan A

    2015-02-01

    Lianas are an important component of tropical forests, contributing up to 25% of the woody stems and 35% of woody species diversity. Lianas invest less in structural support but more in leaves compared to trees of similar biomass. These physiological and morphological differences suggest that lianas may interact with neighboring plants in ways that are different from similarly sized trees. However, the vast majority of past liana competition studies have failed to identify the unique competitive effects of lianas by controlling for the amount of biomass removed. We assessed liana competition in the forest understory over the course of 3 years by removing liana biomass and an equal amount of tree biomass in 40 plots at 10 sites in a secondary tropical moist forest in central Panama. We found that growth of understory trees and lianas, as well as planted seedlings, was limited due to competitive effects from both lianas and trees, though the competitive impacts varied by species, season, and size of neighbors. The removal of trees resulted in greater survival of planted seedlings compared to the removal of lianas, apparently related to a greater release from competition for light. In contrast, lianas had a species-specific negative effect on drought-tolerant Dipteryx oleifera seedlings during the dry season, potentially due to competition for water. We conclude that, at local scales, lianas and trees have unique and differential effects on understory dynamics, with lianas potentially competing more strongly during the dry season, and trees competing more strongly for light.

  13. Detecting Tree Stems from Volumetric TLS Data in Forest Environments with Rich Understory

    Directory of Open Access Journals (Sweden)

    Johannes Heinzel

    2016-12-01

    Full Text Available The present study introduces a method to identify tree stems from terrestrial laser scanning (TLS data. We focused on forest environments of diverse and layered structure, which were technically characterized by strong occlusion effects with regards to laser scanning. The number and distribution of tree stems are important information for the management of protective forests against natural hazards, for forest inventory, and for ecological studies. Our approach builds upon a three-dimensional (3D voxel grid transformation of the original point cloud data, followed by two major steps of processing. Firstly, a series of morphological operations removed leaves and branches and left only potential stem segments. Secondly, the stem segments of each tree were combined by a multipart workflow, which uses shape and neighborhood criteria. At the same time, erroneous fragments and noise were removed from the dataset. As a result, each object in the voxel grid was represented by a single connected component referring to one specific tree stem. Testing the method on nine spatially independent plots provided detection rates of 97% for the number and location of stems from mature trees with a diameter >= 12 cm and 84% for smaller trees with a minimum of 130 cm total tree height. In summary, we obtained a dataset covering the number and locations of the stems from both mature and understory trees, while not aiming at a precise reconstruction of the stem shape.

  14. Structure and species composition of ectomycorrhizal fungal communities colonizing seedlings and adult trees of Pinus montezumae in Mexican neotropical forests.

    Science.gov (United States)

    Reverchon, Frédérique; Ortega-Larrocea, María del Pilar; Bonilla-Rosso, Germán; Pérez-Moreno, Jesús

    2012-05-01

    Mexico is a center of diversity for pines, but few studies have examined the ectomycorrhizal (ECM) fungal communities associated with pines in this country. We investigated the ECM communities associated with Pinus montezumae seedlings and mature trees in neotropical forests of central Mexico and compared their structure and species composition. Root tips were sampled on both planted seedlings and naturally occurring adult trees. A total of 42 ECM operational taxonomic units (OTUs) was found on P. montezumae. Diversity and similarity indices showed that community structure was similar for both plant growth stages, but phylogenetic diversity and Chao-estimated richness were higher for seedlings. Species composition differed between communities. The dominant OTUs belonged to the families Atheliaceae, Cortinariaceae, and Sebacinaceae, although different taxa appeared to colonize seedlings and adults. Only 12 OTUs were shared between seedlings and adults, which suggests that ECM fungi which colonize seedlings are still not fully incorporated into mycelial networks and that ECM taxa colonizing young individuals of P. montezumae are likely to come from fungal propagules. Intra-generic diversity could be an insurance mechanism to maintain forest productivity under stressed conditions. This is the first report describing the abundance of Atheliaceae in tree roots in neotropical ecosystems. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  15. A window of opportunity for climate-change adaptation: easing tree mortality by reducing forest basal area

    Science.gov (United States)

    John B Bradford; David M Bell

    2016-01-01

    Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area – the cross-sectional area of tree stems within a given ground area – can decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential effectiveness of...

  16. Size-dependence of tree growth response to drought for Norway spruce and European beech individuals in monospecific and mixed-species stands.

    Science.gov (United States)

    Ding, H; Pretzsch, H; Schütze, G; Rötzer, T

    2017-09-01

    Climate anomalies have resulted in changing forest productivity, increasing tree mortality in Central and Southern Europe. This has resulted in more severe and frequent ecological disturbances to forest stands. This study analysed the size-dependence of growth response to drought years based on 384 tree individuals of Norway spruce [Picea abies (L.) Karst.] and European beech [Fagus sylvatica ([L.)] in Bavaria, Germany. Samples were collected in both monospecific and mixed-species stands. To quantify the growth response to drought stress, indices for basal area increment, resistance, recovery and resilience were calculated from tree ring measurements of increment cores. Linear mixed models were developed to estimate the influence of drought periods. The results show that ageing-related growth decline is significant in drought years. Drought resilience and resistance decrease significantly with growth size among Norway spruce individuals. Evidence is also provided for robustness in the resilience capacity of European beech during drought stress. Spruce benefits from species mixing with deciduous beech, with over-yielding spruce in pure stands. The importance of the influence of size-dependence within tree growth studies during disturbances is highlighted and should be considered in future studies of disturbances, including drought. © 2017 German Botanical Society and The Royal Botanical Society of the Netherlands.

  17. Water and Forest Health: Drought Stress as a Core Driver of Forest Disturbances and Tree Mortality in Western North America

    Science.gov (United States)

    Allen, C. D.; Williams, P.

    2012-12-01

    Increasing warmth and dry climate conditions have affected large portions of western North America in recent years, causing elevated levels of both chronic and acute forest drought stress. In turn, increases in drought stress amplify the incidence and severity of the most significant forest disturbances in this region, including wildfire, drought-induced tree mortality, and outbreaks of damaging insects and diseases. Regional patterns of drought stress and various forest disturbances are reviewed, including interactions among climate and the various disturbance processes; similar global-scale patterns and trends of drought-amplified forest die-off and high-severity wildfire also are addressed. New research is presented that derives a tree-ring-based Forest Drought Stress Index (FDSI) for the three most widespread conifer species (Pinus edulis, Pinus ponderosa, and Pseudotsuga menziesii) in the southwestern US (Arizona, New Mexico), demonstrating nonlinear escalation of FDSI to levels unprecedented in the past 1000 years, in response to both drought and especially recent warming. This new work further highlights strong correlations between drought stress and amplified forest disturbances (fire, bark beetle outbreaks), and projects that by ca. 2050 anticipated regional warming will cause mean FDSI levels to reach extreme levels that may exceed thresholds for the survival of current tree species in large portions of their current range. Given recent trends of forest disturbance and projections for substantially warmer temperatures and greater drought stress for much of western North America in coming years, the growing risks to western forest health are becoming clear. This emerging understanding suggests an urgent need to determine potentials and methods for managing water on-site to maintain the vigor and resilience of western forests in the face of increasing levels of climate-induced water stress.

  18. Abundance of Green Tree Frogs and Insects in Artificial Canopy Gaps in a Bottomland Hardwood Forest.

    Energy Technology Data Exchange (ETDEWEB)

    Horn, Scott; Hanula, James, L.; Ulyshen, Michael D.; Kilgo, John, C.

    2005-04-01

    ABSTRACT - We found more green tree frogs ( Hyla cinerea) n canopv gaps than in closed canopy forest. Of the 331 green tree frogs observed, 88% were in canopv gaps. Likewise, higher numbers and biomasses of insects were captured in the open gap habitat Flies were the most commonlv collected insect group accounting for 54% of the total capture. These data suggest that one reason green tree frogs were more abundant in canopy gaps was the increased availability of prey and that small canopy gaps provide early successional habitats that are beneficial to green tree frog populations.

  19. Ecological Importance of Large-Diameter Trees in a Temperate Mixed-Conifer Forest

    Science.gov (United States)

    Lutz, James A.; Larson, Andrew J.; Swanson, Mark E.; Freund, James A.

    2012-01-01

    Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m2. We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD = 114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances trees and spatial relationships between large-diameter and small-diameter trees. Long-term observations may reveal regulation of forest biomass and spatial structure by fire, wind, pathogens, and insects in Sierra Nevada mixed-conifer forests. Sustaining ecosystem functions such as carbon storage or provision of specialist species habitat will likely require different management strategies when the functions are performed primarily by a few large trees as opposed to many smaller trees. PMID:22567132

  20. Hydrological properties of bark of selected forest tree species. Part 2: Interspecific variability of bark water storage capacity

    Directory of Open Access Journals (Sweden)

    Ilek Anna

    2017-06-01

    Full Text Available The subject of the present research is the water storage capacity of bark of seven forest tree species: Pinus sylvestris L., Larix decidua Mill., Abies alba Mill., Pinus sylvestris L., Quercus robur L., Betula pendula Ehrh. and Fagus sylvatica L. The aim of the research is to demonstrate differences in the formation of bark water storage capacity between species and to identify factors influencing the hydrological properties of bark. The maximum water storage capacity of bark was determined under laboratory conditions by performing a series of experiments simulating rainfall and by immersing bark samples in containers filled with water. After each single experiment, the bark samples were subjected to gravity filtration in a desiccator partially filled with water. The experiments lasted from 1084 to 1389 hours, depending on the bark sample. In all the studied species, bark sampled from the thinnest trees is characterized by the highest water storage capacity expressed in mm H2O · cm-3, while bark sampled from the thickest trees - by the lowest capacity. On the other hand, bark sampled from the thickest trees is characterized by the highest water storage capacity expressed in H2O · cm-2 whereas bark from the thinnest trees - by the lowest capacity. In most species tested, as the tree thickness and thus the bark thickness and the coefficient of development of the interception surface of bark increase, the sorption properties of the bark decrease with bark depth, and the main role in water retention is played by the outer bark surface. The bark of European beech is an exception because of the smallest degree of surface development and because the dominant process is the absorption of water. When examining the hydrological properties of bark and calculating its parameters, one needs to take into account the actual surface of the bark of trees. Disregarding the actual bark surface may lead to significant errors in the interpretation of research

  1. Tropical forest carbon sink depends on tree functional diversity and competition

    Science.gov (United States)

    Levy, J.; Medvigy, D.; Hedin, L.; Batterman, S. A.; Xu, X.

    2013-12-01

    Tropical forests serve an essential role in climate change mitigation by removing CO2 from the atmosphere, but the size of the tropical carbon sink may depend on the composition of tree functional types within the forest and the nutrient environment in which they grow. A key uncertainty in forest carbon cycling research is how tree functional diversity and competition for nutrients, water, and light interact to constrain the forest carbon sink following disturbance events. In this study, we present a newly developed C-N cycle for the Ecosystem Demography model version 2 (ED2). This model is capable of resolving C and nutrient dynamics at the scale of individual trees and communities while giving fundamental insights into the ability of tropical forests to serve as carbon sinks. We evaluate the role of nitrogen fixing plant functional types in forest carbon recovery following a stand replacing disturbance. We compare model results with field observations of forest regrowth and nitrogen fixation in young recovering Panamanian forests and find that the model is capable of creating the successional pattern in plant functional types and the pattern of fixation that we observe in Panama.

  2. Tree diversity does not always improve resistance of forest ecosystems to drought

    DEFF Research Database (Denmark)

    Grossiord, Charlotte; Granier, André; Ratcliffe, Sophia

    2014-01-01

    Climate models predict an increase in the intensity and frequency of drought episodes in the Northern Hemisphere. Among terrestrial ecosystems, forests will be profoundly impacted by drier climatic conditions, with drastic consequences for the functions and services they supply. Simultaneously......, biodiversity is known to support a wide range of forest ecosystem functions and services. However, whether biodiversity also improves the resistance of these ecosystems to drought remains unclear. We compared soil drought exposure levels in a total of 160 forest stands within five major forest types across...... in two forest types, suggesting that species interactions in these forests diminished the drought exposure of the ecosystem. However, the other three forest types were unaffected by tree species diversity. We conclude that higher diversity enhances resistance to drought events only in drought...

  3. Advances in ecological genomics in forest trees and applications to genetic resources conservation and breeding.

    Science.gov (United States)

    Holliday, Jason A; Aitken, Sally N; Cooke, Janice E K; Fady, Bruno; González-Martínez, Santiago C; Heuertz, Myriam; Jaramillo-Correa, Juan-Pablo; Lexer, Christian; Staton, Margaret; Whetten, Ross W; Plomion, Christophe

    2017-02-01

    Forest trees are an unparalleled group of organisms in their combined ecological, economic and societal importance. With widespread distributions, predominantly random mating systems and large population sizes, most tree species harbour extensive genetic variation both within and among populations. At the same time, demographic processes associated with Pleistocene climate oscillations and land-use change have affected contemporary range-wide diversity and may impinge on the potential for future adaptation. Understanding how these adaptive and neutral processes have shaped the genomes of trees species is therefore central to their management and conservation. As for many other taxa, the advent of high-throughput sequencing methods is expected to yield an understanding of the interplay between the genome and environment at a level of detail and depth not possible only a few years ago. An international conference entitled 'Genomics and Forest Tree Genetics' was held in May 2016, in Arcachon (France), and brought together forest geneticists with a wide range of research interests to disseminate recent efforts that leverage contemporary genomic tools to probe the population, quantitative and evolutionary genomics of trees. An important goal of the conference was to discuss how such data can be applied to both genome-enabled breeding and the conservation of forest genetic resources under land use and climate change. Here, we report discoveries presented at the meeting and discuss how the ecological genomic toolkit can be used to address both basic and applied questions in tree biology. © 2016 John Wiley & Sons Ltd.

  4. Characterization of Rosaceae tree species in a young Turkey oak-dominated coppice forest

    Directory of Open Access Journals (Sweden)

    Giulietti V

    2009-09-01

    Full Text Available First results of a trial carried out in an experimental area (“Comunità Montana Colline Metallifere”, Tuscany. After coppicing (winter 1998-1999, 77 Sorbus torminalis, Sorbus domestica and others valuable tree species were released on the whole of 220 standard trees per hectare. Aim of the present study was to estimate the opportunity to produce valuable timber from standards of sporadic tree species living into coppice forests. A research trial aimed at evaluating stem and crown quality as well as radial growth of standards after coppicing was carried out in an area 3 hectares wide. Wild service tree, Service tree and Turkey oak trees were analysed. Seven years after coppicing, the growth pattern of the different species, was also analysed by means of two structural transects. In the early phase after coppicing, root and stump suckers of both Sorbus species (especially Service tree are able to compete with Turkey oak sprouts as for height growth. In the following stage, the social regression of Sorbus trees is easily foreseeible because of the high competitive ability of Quercus. The good stem and crown shaping showed to be characters owned by a few Sorbus standards only. These were characterized as the largest-sized and early well-crown shaped trees. The same trees showed the highest dbh growth and developed few epicormic branches. A better targeted selection rule of valuable timber tree species to build up the standards’ stock is the recommended practice to improve forest biodiversity, as well as to create an economically important additional option to firewood, usually produced in these coppice forests.

  5. Residual Long-Term Effects of Forest Fertilization on Tree Growth and Nitrogen Turnover in Boreal Forest

    Directory of Open Access Journals (Sweden)

    Fredrik From

    2015-04-01

    Full Text Available The growth enhancing effects of forest fertilizer is considered to level off within 10 years of the application, and be restricted to one forest stand rotation. However, fertilizer induced changes in plant community composition has been shown to occur in the following stand rotation. To clarify whether effects of forest fertilization have residual long-term effects, extending into the next rotation, we compared tree growth, needle N concentrations and the availability of mobile soil N in young (10 years Pinus sylvestris L. and Picea abies (L. H. Karst. stands. The sites were fertilized with 150 kg·N·ha−1 once or twice during the previous stand rotation, or unfertilized. Two fertilization events increased tree height by 24% compared to the controls. Needle N concentrations of the trees on previously fertilized sites were 15% higher than those of the controls. Soil N mineralization rates and the amounts of mobile soil NH4-N and NO3-N were higher on sites that were fertilized twice than on control sites. Our study demonstrates that operational forest fertilization can cause residual long-term effects on stand N dynamics, with subsequent effects on tree growth that may be more long-lasting than previously believed, i.e., extending beyond one stand rotation.

  6. Giant eucalypts - globally unique fire-adapted rain-forest trees?

    Science.gov (United States)

    Tng, D Y P; Williamson, G J; Jordan, G J; Bowman, D M J S

    2012-11-01

    CONTENTS: Summary    1 I. Introduction    1 II. Giant eucalypts in a global context    2 III. Giant eucalypts - taxonomy and distribution    4 IV. Growth of giant eucalypts    6 V. Fire and regeneration of giant eucalypts    8 VI. Are giant eucalypts different from other rain-forest trees?    9 VII. Conclusions 10 Acknowledgements 11 References 11 SUMMARY: Tree species exceeding 70 m in height are rare globally. Giant gymnosperms are concentrated near the Pacific coast of the USA, while the tallest angiosperms are eucalypts (Eucalyptus spp.) in southern and eastern Australia. Giant eucalypts co-occur with rain-forest trees in eastern Australia, creating unique vegetation communities comprising fire-dependent trees above fire-intolerant rain-forest. However, giant eucalypts can also tower over shrubby understoreys (e.g. in Western Australia). The local abundance of giant eucalypts is controlled by interactions between fire activity and landscape setting. Giant eucalypts have features that increase flammability (e.g. oil-rich foliage and open crowns) relative to other rain-forest trees but it is debatable if these features are adaptations. Probable drivers of eucalypt gigantism are intense intra-specific competition following severe fires, and inter-specific competition among adult trees. However, we suggest that this was made possible by a general capacity of eucalypts for 'hyper-emergence'. We argue that, because giant eucalypts occur in rain-forest climates and share traits with rain-forest pioneers, they should be regarded as long-lived rain-forest pioneers, albeit with a particular dependence on fire for regeneration. These unique ecosystems are of high conservation value, following substantial clearing and logging over 150 yr. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  7. Detection and Segmentation of Small Trees in the Forest-Tundra Ecotone Using Airborne Laser Scanning

    Directory of Open Access Journals (Sweden)

    Marius Hauglin

    2016-05-01

    Full Text Available Due to expected climate change and increased focus on forests as a potential carbon sink, it is of interest to map and monitor even marginal forests where trees exist close to their tolerance limits, such as small pioneer trees in the forest-tundra ecotone. Such small trees might indicate tree line migrations and expansion of the forests into treeless areas. Airborne laser scanning (ALS has been suggested and tested as a tool for this purpose and in the present study a novel procedure for identification and segmentation of small trees is proposed. The study was carried out in the Rollag municipality in southeastern Norway, where ALS data and field measurements of individual trees were acquired. The point density of the ALS data was eight points per m2, and the field tree heights ranged from 0.04 to 6.3 m, with a mean of 1.4 m. The proposed method is based on an allometric model relating field-measured tree height to crown diameter, and another model relating field-measured tree height to ALS-derived height. These models are calibrated with local field data. Using these simple models, every positive above-ground height derived from the ALS data can be related to a crown diameter, and by assuming a circular crown shape, this crown diameter can be extended to a crown segment. Applying this model to all ALS echoes with a positive above-ground height value yields an initial map of possible circular crown segments. The final crown segments were then derived by applying a set of simple rules to this initial “map” of segments. The resulting segments were validated by comparison with field-measured crown segments. Overall, 46% of the field-measured trees were successfully detected. The detection rate increased with tree size. For trees with height >3 m the detection rate was 80%. The relatively large detection errors were partly due to the inherent limitations in the ALS data; a substantial fraction of the smaller trees was hit by no or just a few

  8. Forest trees in human modified landscapes: ecological and genetic drivers of recruitment failure in Dysoxylum malabaricum (Meliaceae).

    Science.gov (United States)

    Ismail, Sascha A; Ghazoul, Jaboury; Ravikanth, Gudasalamani; Kushalappa, Cheppudira G; Uma Shaanker, Ramanan; Kettle, Chris J

    2014-01-01

    Tropical agro-forest landscapes are global priority areas for biodiversity conservation. Little is known about the ability of these landscapes to sustain large late successional forest trees upon which much forest biodiversity depends. These landscapes are subject to fragmentation and additional habitat degradation which may limit tree recruitment and thus compromise numerous ecosystem services including carbon storage and timber production. Dysoxylum malabaricum is a large canopy tree species in the Meliaceae, a family including many important tropical timber trees. This species is found in highly fragmented forest patches within a complex agro-forest landscape of the Western Ghats biodiversity hot spot, South India. In this paper we combined a molecular assessment of inbreeding with ecological and demographic data to explore the multiple threats to recruitment of this tree species. An evaluation of inbreeding, using eleven microsatellite loci in 297 nursery-reared seedlings collected form low and high density forest patches embedded in an agro-forest matrix, shows that mating between related individuals in low density patches leads to reduced seedling performance. By quantifying habitat degradation and tree recruitment within these forest patches we show that increasing canopy openness and the increased abundance of pioneer tree species lead to a general decline in the suitability of forest patches for the recruitment of D. malabaricum. We conclude that elevated inbreeding due to reduced adult tree density coupled with increased degradation of forest patches, limit the recruitment of this rare late successional tree species. Management strategies which maintain canopy cover and enhance local densities of adult trees in agro-forest mosaics will be required to ensure D. malabaricum persists in these landscapes. Our study highlights the need for a holistic understanding of the incipient processes that threaten populations of many important and rare tropical tree

  9. Floristics of mangrove tree species in Angke-Kapuk Protected Forest

    Directory of Open Access Journals (Sweden)

    RUGAYAH

    2005-01-01

    Full Text Available Angke-Kapuk Protected Forest with total area 44.76 ha is part of the Tegal Alur-Angke Kapuk mangrove forests. Therefore, this forest has important role as an interface between terrestrial and marine ecosystems, whether physical, biological or social-economic aspects, to determine mangrove ecosystem as a productive and unique ecosystem in the coastal area. However, the study of floristic of the mangrove vegetation in this forest has never to be done previously. According to the study on September to November 2003, in this forest found 8 species of mangrove trees. The tree species can be classified into two groups. The first group is true mangroves (7 species, i.e. Avicennia officinalis, Rhizophora apiculata, R. mucronata, R. stylosa, Sonneratia caseolaris (major component, Excoecaria agallocha, and Xylocarpus moluccensis (minor component. The last group is mangrove associate, i.e. Terminalia catappa. In this forest also found 7 tree species, i.e. Bruguiera gymnorrhiza, Calophyllum inophyllum, Cerbera manghas, Paraserianthes falcataria, Tamarindus indicus, Acacia mangium, and A. auriculiformis as introduced species. The growth level of B. gymnorhiza, C. inophyllum and C. manghas up to now is seedling and sapling, while the growth level of another introduced species is till in pole and tree.

  10. Projected effects of climate change on the carbon stocks of European beech (Fagus sylvatica L. forests in Zala County, Hungary

    Directory of Open Access Journals (Sweden)

    Somogyi Zoltán

    2016-03-01

    Full Text Available Recent studies suggest that climate change will lead to the local extinction of many tree species from large areas during this century, affecting the functioning and ecosystem services of many forests. This study reports on projected carbon losses due to the assumed local climate change-driven extinction of European beech (Fagus sylvatica L. from Zala County, South-Western Hungary, where the species grows at the xeric limit of its distribution. The losses were calculated as a difference between carbon stocks in climate change scenarios assuming an exponentially increasing forest decline over time, and those in a baseline scenario assuming no climate change. In the climate change scenarios, three different sets of forest management adaptation measures were studied: (1 only harvesting damaged stands, (2 additionally salvaging dead trees that died due to climate change, and (3 replacing, at an increasing rate over time, beech with sessile oak (Quercus petraea Matt. Lieb. after final harvest. Projections were made using the open access carbon accounting model CASMOFOR based on modeling or assuming effects of climate change on mortality, tree growth, root-to-shoot ratio and decomposition rates. Results demonstrate that, if beech disappears from the region as projected by the end of the century, over 80% of above-ground biomass carbon, and over 60% of the carbon stocks of all pools (excluding soils of the forests will be lost by 2100. Such emission rates on large areas may have a discernible positive feedback on climate change, and can only partially be offset by the forest management adaptation measures.

  11. Tree structural and species diversities in Okwangwo Forest, Cross ...

    African Journals Online (AJOL)

    ... tree species encountered were threatened/endangered, 23 species were rare with only 3 tree species (Brachystegia eurycoma, Bailonella toxisperma and Ceiba pentandra) being abundant in the area. Frequent and occasional species were not encountered in the area. Leguminoseae was the most represented family ...

  12. Status of Indigenous Tree Species in Girei Forest Reserve of ...

    African Journals Online (AJOL)

    ... sampled plot (p > 0.05). At this point of endangerment of the indigenous tree species, there is therefore a need for conservation strategies for future use of these indigenous trees and to reduce the effect of global warming on the earth surface. Keywords: Quantitative assessment, Global warming, Indigenous, Conservation, ...

  13. LiDAR Individual Tree Detection for Assessing Structurally Diverse Forest Landscapes

    Science.gov (United States)

    Jeronimo, Sean

    Contemporary forest management on public land incorporates a focus on restoration and maintenance of ecological functions through silvicultural manipulation of forest structure on a landscape scale. Incorporating reference conditions into restoration treatment planning and monitoring can improve treatment efficacy, but the typical ground-based methods of quantifying reference condition data---and comparing it to pre- and post-treatment stands---are expensive, time-consuming, and limited in scale. Airborne LiDAR may be part of the solution to this problem, since LiDAR acquisitions have both broad coverage and high resolution. I evaluated the ability of LiDAR Individual Tree Detection (ITD) to describe forest structure across a structurally variable landscape in support of large-scale forest restoration. I installed nineteen 0.25 ha stem map plots across a range of structural conditions in potential reference areas (Yosemite National Park) and potential restoration treatment areas (Sierra National Forest) in the Sierra Nevada of California. I used the plots to evaluate a common ITD algorithm, the watershed transform, compare it to past uses of ITD, and determine which aspects of forest structure contributed to errors in ITD. I found that ITD across this structurally diverse landscape was generally less accurate than across the smaller and less diverse areas over which it has previously been studied. However, the pattern of tree recognition is consistent: regardless of forest structure, canopy dominants are almost always detected and relatively shorter trees are almost never detected. Correspondingly, metrics dominated by large trees, such as biomass, basal area, and spatial heterogeneity, can be measured using ITD, while metrics dominated by smaller trees, such as stand density, cannot. Bearing these limitations in mind, ITD can be a powerful tool for describing forest structure across heterogeneous landscape restoration project areas.

  14. Drought-related tree mortality in drought-resistant semi-arid Aleppo pine forest

    Science.gov (United States)

    Preisler, Yakir; Grünzweig, José M.; Rotenberg, Eyal; Rohatyn, Shani; Yakir, Dan

    2014-05-01

    The frequency and intensity of drought events are expected to increase as part of global climate change. In fact, drought related tree mortality had become a widespread phenomenon in forests around the globe in the past decades. This study was conducted at the Yatir FLUXNET site, located in a 45 years old Pinus halepensis dominated forest that successfully sustained low mean annual precipitation (276mm) and extended seasonal droughts (up to 340 days between rain events). However, five recent non-consecutive drought years led to enhanced tree mortality in 2010 (5-10% of the forest population, which was not observed hitherto). The Tree mortality was characterized by patchiness, showing forest zones with either >80% mortality or no mortality at all. Areas of healthy trees were associated with deeper root distribution and increased stoniness (soil pockets & cracks). To help identify possible causes of the increased mortality and its patterns, four tree stress levels were identified based on visual appearance, and studied in more detail. This included examining from spring 2011 to summer 2013 the local trees density, root distribution, annual growth rings, needle length and chlorophyll content, rates of leaf gas exchange, and branch predawn water potential. Tree phenotypic stress level correlated with the leaf predawn water potential (-1.8 and -3.0 in healthy and stressed trees, respectively), which likely reflected tree-scale water availability. These below ground characteristics were also associated, in turn, with higher rate of assimilation (3.5 and 0.8 μmol CO2 m-2s1 in healthy and stress trees, respectively), longer needles (8.2cm and 3.4 cm in healthy and stressed trees, respectively). Annual ring widths showed differences between stress classes, with stressed trees showing 30% narrower rings on average than unstressed trees. Notably, decline in annual ring widths could be identified in currently dead or severely stressed trees 15-20 years prior to mortality or

  15. Human Influences on Tree Diversity and Composition of a Coastal Forest Ecosystem: The Case of Ngumburuni Forest Reserve, Rufiji, Tanzania

    Directory of Open Access Journals (Sweden)

    J. Kimaro

    2013-01-01

    Full Text Available This paper reports on the findings of an ecological survey conducted in Ngumburuni Forest Reserve, a biodiversity rich forest reserve within the coastal forests of Tanzania. The main goal of this study was to determine the influence of uncontrolled anthropogenic activities on tree species diversity and composition within the forest ecosystem. It was revealed that economic activities including logging, charcoaling, and shifting cultivation were the most important disturbing activities affecting ecological functioning and biodiversity integrity of the forest. Further to this, we noted that the values of species diversity, composition, and regeneration potential within the undisturbed forest areas were significantly different from those in heavily disturbed areas. These observations confirm that the ongoing human activities have already caused size quality degradation of useful plants, enhanced species diversification impacts to the forest ecosystem, and possibly negatively affected the livelihoods of the adjacent local communities. Despite these disturbances, Ngumburuni forest reserve still holds important proportions of both endemic and threatened animal and plant species. The study suggests urgent implementation of several conservation measures in order to limit accessibility to the forest resources so as to safeguard the richness and abundance of useful biodiversity stocks in the reserve.

  16. Influence of forest degradation on tree diversity in a forest-savannah ...

    African Journals Online (AJOL)

    Results showed that landscape and forest disturbance, characterized by a forest canopy opening up, led to an increase of light-tolerant species and their richness in degraded forests. Thus, if diversity is summarized to species richness, forest ... anthropogenic disturbances. In non-degraded forests, abundance distribution ...

  17. Deciduous trees are a large and overlooked sink for snowmelt water in the boreal forest

    Science.gov (United States)

    Young, Jessica; Bolton, W. Robert; Bhatt, Uma; Cristobal, Jordi; Thoman, Richard

    2016-01-01

    The terrestrial water cycle contains large uncertainties that impact our understanding of water budgets and climate dynamics. Water storage is a key uncertainty in the boreal water budget, with tree water storage often ignored. The goal of this study is to quantify tree water content during the snowmelt and growing season periods for Alaskan and western Canadian boreal forests. Deciduous trees reached saturation between snowmelt and leaf-out, taking up 21–25% of the available snowmelt water, while coniferous trees removed boreal deciduous tree area is expected to increase by 1–15%, potentially resulting in an additional 0.3–3 billion m3 of snowmelt water removed from the soil per year. This study is the first to show that deciduous tree water uptake of snowmelt water represents a large but overlooked aspect of the water balance in boreal watersheds.

  18. Protecting the forests while allowing removal of damaged trees may imperil saproxylic insect biodiversity in the Hyrcanian Beech Forests of Iran

    Science.gov (United States)

    Müller Jörg; Thorn Simon; Baier Roland; Sagheb-Talebi Khosro; Barimani Hassan V.; Seibold Sebastian; Michael D. Ulyshen; Gossner Martin M.

    2015-01-01

    The 1.8 million ha of forest south of the Caspian Sea represent a remarkably intact ecosystem with numerous old-growth features and unique species assemblages. To protect these forests, Iranian authorities recently passed a law which protects healthy trees but permits the removal of injured, dying and dead trees. To quantify the biodiversity effects of this strategy,...

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

    Directory of Open Access Journals (Sweden)

    Cecilia Smith-Ramírez

    2016-05-01

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

  20. Above-ground tree outside forest (TOF) phytomass and carbon ...

    Indian Academy of Sciences (India)

    The ancillary datasets such as topograph- ical map, district forest working plan, FRI/FSI publications (2000, 2003, 2007), soil maps, ASTER global digital elevation model (GDEM), forest cover type and density map from FSI (2005) were also used to assist the classification of TOF classes, to know the spatial distribution and ...

  1. Dead and lying trees: essential for life in the forest.

    Science.gov (United States)

    Sally. Duncan

    1999-01-01

    Twenty years after publication of a report on wildlife habitat in managed east-side forests, Pacific Northwest Research Station scientists Evelyn Bull, Catherine Parks, and Torolf Torgersen, are updating that report and discovering that the current direction for providing wildlife habitat on public forest lands does not reflect findings from research since 1979. More...

  2. Tree Diversity Limits the Impact of an Invasive Forest Pest.

    Directory of Open Access Journals (Sweden)

    Virginie Guyot

    Full Text Available The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the "resource concentration hypothesis" the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the "natural enemy hypothesis" suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus on chestnut trees (Castanea sativa in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures to four species (mixtures of chestnut and three broadleaved species. Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall.

  3. Tree Diversity Limits the Impact of an Invasive Forest Pest

    Science.gov (United States)

    Guyot, Virginie; Castagneyrol, Bastien; Vialatte, Aude; Deconchat, Marc; Selvi, Federico; Bussotti, Filippo; Jactel, Hervé

    2015-01-01

    The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the “resource concentration hypothesis” the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the “natural enemy hypothesis” suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut trees (Castanea sativa) in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures) to four species (mixtures of chestnut and three broadleaved species). Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall. PMID:26360881

  4. Understory and small trees contribute importantly to stemflow of a lower montane cloud forest

    Science.gov (United States)

    González Martínez, T. M.; Wiliams-Linera, G.; Holwerda, F.

    2016-12-01

    Stemflow (Sf) measurements in rainforests and montane forests dominated by large trees rarely include the understory and small trees. In the present study, contributions of woody understory (> 1 m height and 10 cm DBH) to overall Sf of a lower montane cloud forest in central Veracruz, Mexico, were quantified. Incident precipitation (P), Sf volume and vegetation structure were measured. Subsequently, stemflow funneling ratios (SFR) were calculated, and allometric relationships between tree basal area and Sf volume were used to scale up measurements from individual trees to the stand level. Additionally, two other common methods to calculate areal Sf were used for comparative purposes. Understory woody plants, small trees and upper canopy trees represented 96, 2 and 2 %, respectively, of the total density. Upper canopy trees had the lowest SFRs (1.6 ± 0.5 on average), while the lower understory (> 1 m and 2 m) presented similar SFRs (22.9 ± 5.4 and 20.2 ± 3.9, respectively). Different scaling methods yielded very similar results for all but the upper understory. Overall areal Sf during the study period was 19 mm (3.8 % of rainfall), to which the understory contributed 66.3 % (12.6 mm), small trees 12.6 % (2.4 mm) and upper canopy trees 21.1 % (4.0 mm). Our results suggest that woody understory vegetation and small trees can have an important role in Sf generation of tall humid tropical forests, provided that the density of plants in these groups is high enough.

  5. [Phenology of the tree Sideroxylon capiri (Sapotaceae) at the tropical dry forest in Costa Rica].

    Science.gov (United States)

    Garcia, Elmer G; Di Stefano, José F

    2005-01-01

    From March 1996 until February 2000, an study about the phenology of the Tempisque tree [Sideroxylon capiri (A.DC.) Pittier] was made in the Tropical Dry Forest of the Barra Honda National Park (Costa Rica). Ten trees were chosen at random and their phenology was evaluated monthly during the first two years and every two months afterwards. Climatological data were also collected in situ. Trees change their foliage each year during the rainy season or at the beginning of the dry season. In contrast with other native species in forest, soil water deficit is not responsible for foliage change in S. capiri. Some elements that affect the process are photoperiod and herbivores. Unknown physiological mechanisms allow the tree to maintain foliage during the driest months (March and April). Flowering and fruiting may occur every year and in any season, but mostly in the dry season, with variability both among seasons and among individuals.

  6. Tree Species Diversity and Population Structure in the Tropical Forests of North Central Eastern Ghats, India

    Directory of Open Access Journals (Sweden)

    Dumpa PREMAVANI

    2014-12-01

    Full Text Available The tree species diversity and population structure were studied in four stands of the tropical forests in the north-central Eastern Ghats, based on tree inventories conducted on four 1-ha plots. In the four independent plots, two 5 x 1000 m transects were established and all trees with ≥ 15 cm girth at breast height were enumerated. The density, frequency, basal area and IVI along with diversity indices viz. Shannon index, species richness, equitability and species dominance were computed to see the variation in tree community. A total of 92 species representing 73 genera under 40 families of angiosperms were recorded. Tree species richness was as low as 34 species per hectare plot in Geddapalli to as high as 48 species in Koruturu. Tree density ranged from 360 stems per hectare in plot Geddapalli to 526 stems in plot Chintapalli and that of total basal area from 16.31 m2 ha-1 in Koruturu to 31.15 m2 ha-1 in Chintapalli. The number of species and stems decreased from the smaller to the largest girth classes. The tree inventories of the study area when compared to those of the other tropical forests showed great differences in density and basal area. This may probably be due to differences in geography and annual rainfall patterns. The information on tree species structure and function can provide baseline information for conservation of the biodiversity.

  7. Forest understory trees can be segmented accurately within sufficiently dense airborne laser scanning point clouds.

    Science.gov (United States)

    Hamraz, Hamid; Contreras, Marco A; Zhang, Jun

    2017-07-28

    Airborne laser scanning (LiDAR) point clouds over large forested areas can be processed to segment individual trees and subsequently extract tree-level information. Existing segmentation procedures typically detect more than 90% of overstory trees, yet they barely detect 60% of understory trees because of the occlusion effect of higher canopy layers. Although understory trees provide limited financial value, they are an essential component of ecosystem functioning by offering habitat for numerous wildlife species and influencing stand development. Here we model the occlusion effect in terms of point density. We estimate the fractions of points representing different canopy layers (one overstory and multiple understory) and also pinpoint the required density for reasonable tree segmentation (where accuracy plateaus). We show that at a density of ~170 pt/m² understory trees can likely be segmented as accurately as overstory trees. Given the advancements of LiDAR sensor technology, point clouds will affordably reach this required density. Using modern computational approaches for big data, the denser point clouds can efficiently be processed to ultimately allow accurate remote quantification of forest resources. The methodology can also be adopted for other similar remote sensing or advanced imaging applications such as geological subsurface modelling or biomedical tissue analysis.

  8. TREES AND REGENERATION IN RUBBER AGROFORESTS AND OTHER FOREST-DERIVED VEGETATION IN JAMBI (SUMATRA, INDONESIA

    Directory of Open Access Journals (Sweden)

    Hesti L. Tata

    2008-06-01

    Full Text Available The rubber  agroforests  (RAF  of Indonesia provide  a dynamic interface  between natural  processes  of forest  regeneration and  human’s management   targeting  the harvesting  of latex  with  minimum investment  of time  and financial  resources.  The composition  and species richness  of higher  plants  across an intensification gradient from forest to monocultures of tree crops have been investigated  in six land use types (viz. secondary forest, RAF, rubber monoculture, oil palm plantation, cassava field and Imperata grassland  in Bungo,  Jambi  Province,  Indonesia.  We emphasize  comparison of four different  strata  (understory, seedling,  sapling  and tree of vegetation  between forest and RAF,  with  specific interest  in plant  dependence  on ectomycorrhiza fungi. Species richness  and species accumulation curves for seedling  and sapling  stages were similar  between forest and RAF,  but in the tree stratum  (trees > 10 cm dbh selective thinning by farmers was evident in a reduction  of species diversity and an increase in the proportion of trees with edible parts. Very few trees dependent on ectomycorrhiza fungi were encountered  in the RAF. However, the relative distribution of early and late successional species as evident from the wood density distribution showed no difference between RAF and forest.

  9. Domination of hillslope denudation by tree uprooting in an old-growth forest

    Science.gov (United States)

    Phillips, Jonathan D.; Šamonil, Pavel; Pawlik, Łukasz; Trochta, Jan; Daněk, Pavel

    2017-01-01

    Razula forest preserve in the Carpathian Mountains of the Czech Republic is an unmanaged forest that has not been logged or otherwise anthropically disturbed for at least 83 years, preceded by only infrequent selective logging. We examined this 25 ha area to determine the dominant geomorphological processes on the hillslope. Tree uprooting displaces about 2.9 m3 of soil and regolith per year, representing about 1.5 uprooted trees ha- 1 yr- 1, based on forest inventory records dating back to 1972, and contemporary measurements of displaced soil and pit-mound topography resulting from uprooting. Pits and mounds occupy > 14% of the ground surface. Despite typical slope gradients of 0.05 mm- 1, and up to 0.41, little evidence of mass wasting (e.g., slump or flow scars or deposits, colluvial deposits) was noted in the field, except in association with pit-mound pairs. Small avalanche and ravel features are common on the upslope side of uproot pits. Surface runoff features were rare and poorly connected, but do include stemwash erosion associated with stemflow. No rills or channels were found above the valley bottom area, and only small, localized areas of erosion and forest litter debris indicating overland flow. Where these features occurred, they either disappeared a short distance downslope (indicating infiltration), or indicate flow into tree throw pits. Surface erosion is also inhibited by surface armoring of coarse rock fragments associated with uprooting, as well as by the nearly complete vegetation and litter cover. These results show that the combination of direct and indirect impacts of tree uprooting can dominate slope processes in old-growth, unmanaged forests. The greater observed expression of different hillslope processes in adjacent managed forests (where tree uprooting dynamics are blocked by management activities) suggests that human interventions can change the slope process regime in forest ecosystems.

  10. Impact of Forest Fragmentation on Patterns of Mountain Pine Beetle-Caused Tree Mortality

    Directory of Open Access Journals (Sweden)

    Trisalyn A. Nelson

    2013-04-01

    Full Text Available The current outbreak of mountain pine beetle, Dendroctonus ponderosae Hopkins, has led to extensive tree mortality in British Columbia and the western United States. While the greatest impacts of the outbreak have been in British Columbia, ongoing impacts are expected as the outbreak continues to spread eastward towards Canada’s boreal and eastern pine forests. Successful mitigation of this outbreak is dependent on understanding how the beetle’s host selection behaviour is influenced by the patchwork of tree mortality across the landscape. While several studies have shown that selective mechanisms operate at the individual tree level, less attention has been given to beetles’ preference for variation in spatial forest patterns, namely forest fragmentation, and if such preference changes with changing population conditions. The objective of this study is to explore the influence of fragmentation on the location of mountain pine beetle caused mortality. Using a negative binomial regression model, we tested the significance of a fragmentation measure called the Aggregation Index for predicting beetle-caused tree mortality in the central interior of British Columbia, Canada in 2000 and 2005. The results explain that mountain pine beetle OPEN ACCESS Forests 2013, 4 280 exhibit a density-dependent dynamic behaviour related to forest patterns, with fragmented forests experiencing greater tree mortality when beetle populations are low (2000. Conversely, more contiguous forests are preferred when populations reach epidemic levels (2005. These results reinforce existing findings that bark beetles exhibit a strong host configuration preference at low population levels and that such pressures are relaxed when beetle densities are high.

  11. Role of Armillaria species on tree dying in Turkey oak and Hungarian oak forest in Lipovica

    Directory of Open Access Journals (Sweden)

    Keča Nenad

    2006-01-01

    Full Text Available The species and population structure of Armillaria species were studied in Turkey oak and Hungarian oak forest. Two species were observed, Armillaria gallica and A. mellea. Armillaria mellea was found on only one tree, and A. gallica was found on seven trees. Four gewets of A. gallica were observed of which two were represented only by one isolate each, while two covered the area of 5 and 9 areas respectively.

  12. Tree-Species Classification in Subtropical Forests Using Airborne Hyperspectral and LiDAR Data

    Directory of Open Access Journals (Sweden)

    Xin Shen

    2017-11-01

    Full Text Available Accurate classification of tree-species is essential for sustainably managing forest resources and effectively monitoring species diversity. In this study, we used simultaneously acquired hyperspectral and LiDAR data from LiCHy (Hyperspectral, LiDAR and CCD airborne system to classify tree-species in subtropical forests of southeast China. First, each individual tree crown was extracted using the LiDAR data by a point cloud segmentation algorithm (PCS and the sunlit portion of each crown was selected using the hyperspectral data. Second, different suites of hyperspectral and LiDAR metrics were extracted and selected by the indices of Principal Component Analysis (PCA and the mean decrease in Gini index (MDG from Random Forest (RF. Finally, both hyperspectral metrics (based on whole crown and sunlit crown and LiDAR metrics were assessed and used as inputs to Random Forest classifier to discriminate five tree-species at two levels of classification. The results showed that the tree delineation approach (point cloud segmentation algorithm was suitable for detecting individual tree in this study (overall accuracy = 82.9%. The classification approach provided a relatively high accuracy (overall accuracy > 85.4% for classifying five tree-species in the study site. The classification using both hyperspectral and LiDAR metrics resulted in higher accuracies than only hyperspectral metrics (the improvement of overall accuracies = 0.4–5.6%. In addition, compared with the classification using whole crown metrics (overall accuracies = 85.4–89.3%, using sunlit crown metrics (overall accuracies = 87.1–91.5% improved the overall accuracies of 2.3%. The results also suggested that fewer of the most important metrics can be used to classify tree-species effectively (overall accuracies = 85.8–91.0%.

  13. The ecology of pre-dispersal insect herbivory on tree reproductive structures in natural forest ecosystems

    OpenAIRE

    Boivin, Thomas; Doublet, Violette; Candau, Jean-Noël

    2017-01-01

    Plant-insect interactions are key model systems to assess how some species affect the distribution, the abundance, and the evolution of others. Tree reproductive structures represent a critical resource for many insect species, which can be likely drivers of demography, spatial distribution, and trait diversification of plants. In this review, we present the ecological implications of pre-dispersal herbivory on tree reproductive structures by insects (PIHR) in forest ecosystems. Both insect’s...

  14. Bark traits, decomposition and flammability of Australian forest trees

    NARCIS (Netherlands)

    Grootemaat, Saskia; Wright, Ian J.; Van Bodegom, Peter M.; Cornelissen, Johannes H.C.; Shaw, Veronica

    2017-01-01

    Bark shedding is a remarkable feature of Australian trees, yet relatively little is known about interspecific differences in bark decomposability and flammability, or what chemical or physical traits drive variation in these properties. We measured the decomposition rate and flammability

  15. 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.

  16. Tree- Rings Link Climate and Carbon Storage in a Northern Mixed Hardwood Forest

    Science.gov (United States)

    Chiriboga, A.

    2007-12-01

    The terrestrial biosphere is a variable sink for atmospheric carbon dioxide. It is important to understand how carbon storage in trees is affected by natural climate variability to better characterize the sink. Quantifying the sensitivity of forest carbon storage to climate will improve carbon budgets and have implications for forest management practices. Here we explore how climate variability affects the ability of a northern mixed hardwood forest in Michigan to sequester atmospheric carbon dioxide in woody tissues. This site is ideal for studies of carbon sequestration; The University of Michigan Biological Station is an Ameriflux site, and has detailed meteorological and biometric records, as well as CO2 flux data. We have produced an 82- year aspen (Populus grandidentata) tree-ring chronology for this site, and measured ring widths at several heights up the bole. These measurements were used to estimate annual wood volume, which represents carbon allocated to aboveground carbon stores. Standard dendroclimatological techniques are used to identify environmental factors (e.g. temperature or precipitation) that drive tree-ring increment variability in the past century, and therefore annual carbon storage in this forest. Preliminary results show that marker years within the tree- ring chronology correspond with years that have cold spring temperatures. This suggests that trees at this site are temperature sensitive.

  17. Tsunami damping by mangrove forest: a laboratory study using parameterized trees

    Directory of Open Access Journals (Sweden)

    A. Strusińska-Correia

    2013-02-01

    Full Text Available Tsunami attenuation by coastal vegetation was examined under laboratory conditions for mature mangroves Rhizophora sp. The developed novel tree parameterization concept, accounting for both bio-mechanical and structural tree properties, allowed to substitute the complex tree structure by a simplified tree model of identical hydraulic resistance. The most representative parameterized mangrove model was selected among the tested models with different frontal area and root density, based on hydraulic test results. The selected parameterized tree models were arranged in a forest model of different width and further tested systematically under varying incident tsunami conditions (solitary waves and tsunami bores. The damping performance of the forest models under these two flow regimes was compared in terms of wave height and force envelopes, wave transmission coefficient as well as drag and inertia coefficients. Unlike the previous studies, the results indicate a significant contribution of the foreshore topography to solitary wave energy reduction through wave breaking in comparison to that attributed to the forest itself. A similar rate of tsunami transmission (ca. 20% was achieved for both flow conditions (solitary waves and tsunami bores and the widest forest (75 m in prototype investigated. Drag coefficient CD attributed to the solitary waves tends to be constant (CD = 1.5 over the investigated range of the Reynolds number.

  18. Tree structure and diversity in human-impacted littoral forests, madagascar.

    Science.gov (United States)

    Ingram, J Carter; Whittaker, Robert J; Dawson, Terence P

    2005-06-01

    This research surveyed human-impacted littoral forests in southeastern Madagascar to determine (i) how forest structural features, indicative of human impact, are related to total, utilitarian, and endemic tree diversity; (ii) the distribution, abundance, and demographics of tree species groups (i.e., total, useful, endemic) across the landscape; and (iii) the amount of basal area available per human use category. We also use these data to consider issues of sustainable use and how human impact may influence littoral forest tree community composition across the landscape. Within 22 transects of 400 m2 each, we recorded a total of 135 tree species and 2155 individuals. Seventy-nine species (58%) were utilitarian and 56 (42%) were nonutilitarian species. Of the 2155 individuals, 1827 (84%) trees were utilitarian species. We recorded 23 endemic species (17% of the total species) and 17 (74%) of these were utilitarian species. Basal area was significantly correlated with Shannon Weiner Index values for total (r = 0.64, P forest structure. Utilitarian species constituted 84% of the total basal area. The use category contributing the highest amount of basal area to the landscape was firewood. The results presented herein demonstrate that the landscape of southeastern Madagascar, commonly perceived as degraded, retains high value for both global conservation purposes and for local livelihoods. Thus, valuable opportunities may exist for developing conservation incentives that leverage both global and local conservation needs.

  19. Tree Diversity Enhances Stand Carbon Storage but Not Leaf Area in a Subtropical Forest.

    Directory of Open Access Journals (Sweden)

    Nadia Castro-Izaguirre

    Full Text Available Research about biodiversity-productivity relationships has focused on herbaceous ecosystems, with results from tree field studies only recently beginning to emerge. Also, the latter are concentrated largely in the temperate zone. Tree species diversity generally is much higher in subtropical and tropical than in temperate or boreal forests, with reasons not fully understood. Niche overlap and thus complementarity in the use of resources that support productivity may be lower in forests than in herbaceous ecosystems, suggesting weaker productivity responses to diversity change in forests. We studied stand basal area, vertical structure, leaf area, and their relationship with tree species richness in a subtropical forest in south-east China. Permanent forest plots of 30 x 30 m were selected to span largely independent gradients in tree species richness and secondary successional age. Plots with higher tree species richness had a higher stand basal area. Also, stand basal area increases over a 4-year census interval were larger at high than at low diversity. These effects translated into increased carbon stocks in aboveground phytomass (estimated using allometric equations. A higher variability in tree height in more diverse plots suggested that these effects were facilitated by denser canopy packing due to architectural complementarity between species. In contrast, leaf area was not or even negatively affected by tree diversity, indicating a decoupling of carbon accumulation from leaf area. Alternatively, the same community leaf area might have assimilated more C per time interval in more than in less diverse plots because of differences in leaf turnover and productivity or because of differences in the display of leaves in vertical and horizontal space. Overall, our study suggests that in species-rich forests niche-based processes support a positive diversity-productivity relationship and that this translates into increased carbon storage in long

  20. Tree Diversity Enhances Stand Carbon Storage but Not Leaf Area in a Subtropical Forest.

    Science.gov (United States)

    Castro-Izaguirre, Nadia; Chi, Xiulian; Baruffol, Martin; Tang, Zhiyao; Ma, Keping; Schmid, Bernhard; Niklaus, Pascal A

    2016-01-01

    Research about biodiversity-productivity relationships has focused on herbaceous ecosystems, with results from tree field studies only recently beginning to emerge. Also, the latter are concentrated largely in the temperate zone. Tree species diversity generally is much higher in subtropical and tropical than in temperate or boreal forests, with reasons not fully understood. Niche overlap and thus complementarity in the use of resources that support productivity may be lower in forests than in herbaceous ecosystems, suggesting weaker productivity responses to diversity change in forests. We studied stand basal area, vertical structure, leaf area, and their relationship with tree species richness in a subtropical forest in south-east China. Permanent forest plots of 30 x 30 m were selected to span largely independent gradients in tree species richness and secondary successional age. Plots with higher tree species richness had a higher stand basal area. Also, stand basal area increases over a 4-year census interval were larger at high than at low diversity. These effects translated into increased carbon stocks in aboveground phytomass (estimated using allometric equations). A higher variability in tree height in more diverse plots suggested that these effects were facilitated by denser canopy packing due to architectural complementarity between species. In contrast, leaf area was not or even negatively affected by tree diversity, indicating a decoupling of carbon accumulation from leaf area. Alternatively, the same community leaf area might have assimilated more C per time interval in more than in less diverse plots because of differences in leaf turnover and productivity or because of differences in the display of leaves in vertical and horizontal space. Overall, our study suggests that in species-rich forests niche-based processes support a positive diversity-productivity relationship and that this translates into increased carbon storage in long-lived woody

  1. Challenges for tree officers to enhance the provision of regulating ecosystem services from urban forests.

    Science.gov (United States)

    Davies, Helen J; Doick, Kieron J; Hudson, Malcolm D; Schreckenberg, Kate

    2017-07-01

    Urbanisation and a changing climate are leading to more frequent and severe flood, heat and air pollution episodes in Britain's cities. Interest in nature-based solutions to these urban problems is growing, with urban forests potentially able to provide a range of regulating ecosystem services such as stormwater attenuation, heat amelioration and air purification. The extent to which these benefits are realized is largely dependent on urban forest management objectives, the availability of funding, and the understanding of ecosystem service concepts within local governments, the primary delivery agents of urban forests. This study aims to establish the extent to which British local authorities actively manage their urban forests for regulating ecosystem services, and identify which resources local authorities most need in order to enhance provision of ecosystem services by Britain's urban forests. Interviews were carried out with staff responsible for tree management decisions in fifteen major local authorities from across Britain, selected on the basis of their urban nature and high population density. Local authorities have a reactive approach to urban forest management, driven by human health and safety concerns and complaints about tree disservices. There is relatively little focus on ensuring provision of regulating ecosystem services, despite awareness by tree officers of the key role that urban forests can play in alleviating chronic air pollution, flood risk and urban heat anomalies. However, this is expected to become a greater focus in future provided that existing constraints - lack of understanding of ecosystem services amongst key stakeholders, limited political support, funding constraints - can be overcome. Our findings suggest that the adoption of a proactive urban forest strategy, underpinned by quantified and valued urban forest-based ecosystem services provision data, and innovative private sector funding mechanisms, can facilitate a change to a

  2. Drivers of forest cover change in Eastern Europe and European Russia, 1985–2012

    DEFF Research Database (Denmark)

    Alix-Garcia, Jennifer; Munteanu, Catalina; Zhao, Na

    2016-01-01

    The relative importance of geography, history, and policy in driving forest cover change at broad scales remains poorly understood. We examine variation in forest cover dynamics over the period 1985–2012 across 19 countries in Eastern Europe and European Russia in order to shed light on the role...... of these in driving forest cover change after the collapse of socialism. Using a combination of cross-section and panel regression methods, we find that privatization of forest lands increased forest cover loss due to logging, as did increases in agricultural land between 1850 and 1900. Land quality has no power...... to explain variation in forest loss between countries, nor does trade and price liberalization policy. None of our covariates explain forest regrowth on non-forested land over the period. We conclude that history and land privatization drove important cross-country variation in forest dynamics in the region...

  3. Propagation of Native Tree Species to Restore Subtropical Evergreen Broad-Leaved Forests in SW China

    Directory of Open Access Journals (Sweden)

    Yang Lu

    2016-01-01

    Full Text Available Subtropical evergreen broad-leaved forest (EBLF is a widespread vegetation type throughout East Asia that has suffered extensive deforestation and fragmentation. Selection and successful propagation of native tree species are important for improving ecological restoration of these forests. We carried out a series of experiments to study the propagation requirements of indigenous subtropical tree species in Southwest China. Seeds of 21 tree species collected from the natural forest were materials for the experiment. This paper examines the seed germination and seedling growth performance of these species in a nursery environment. Germination percentages ranged from 41% to 96% and were ≥50% for 19 species. The median length of germination time (MLG ranged from 24 days for Padus wilsonii to 144 days for Ilex polyneura. Fifteen species can reach the transplant size (≥15 cm in height within 12 months of seed collection. Nursery-grown seedlings for each species were planted in degraded site. Two years after planting, the seedling survival rate was >50% in 18 species and >80% in 12 species. Based on these results, 17 species were recommended as appropriate species for nursery production in forest restoration projects. Our study contributes additional knowledge regarding the propagation techniques for various native subtropical tree species in nurseries for forest restoration.

  4. Varying rotation lengths in northern production forests: Implications for habitats provided by retention and production trees.

    Science.gov (United States)

    Felton, Adam; Sonesson, Johan; Nilsson, Urban; Lämås, Tomas; Lundmark, Tomas; Nordin, Annika; Ranius, Thomas; Roberge, Jean-Michel

    2017-04-01

    Because of the limited spatial extent and comprehensiveness of protected areas, an increasing emphasis is being placed on conserving habitats which promote biodiversity within production forest. For this reason, alternative silvicultural programs need to be evaluated with respect to their implications for forest biodiversity, especially if these programs are likely to be adopted. Here we simulated the effect of varied rotation length and associated thinning regimes on habitat availability in Scots pine and Norway spruce production forests, with high and low productivity. Shorter rotation lengths reduced the contribution made by production trees (trees grown for industrial use) to the availability of key habitat features, while concurrently increasing the contribution from retention trees. The contribution of production trees to habitat features was larger for high productivity sites, than for low productivity sites. We conclude that shortened rotation lengths result in losses of the availability of habitat features that are key for biodiversity conservation and that increased retention practices may only partially compensate for this. Ensuring that conservation efforts better reflect the inherent variation in stand rotation lengths would help improve the maintenance of key forest habitats in production forests.

  5. Habitat fragmentation, tree diversity, and plant invasion interact to structure forest caterpillar communities.

    Science.gov (United States)

    Stireman, John O; Devlin, Hilary; Doyle, Annie L

    2014-09-01

    Habitat fragmentation and invasive species are two of the most prominent threats to terrestrial ecosystems. Few studies have examined how these factors interact to influence the diversity of natural communities, particularly primary consumers. Here, we examined the effects of forest fragmentation and invasion of exotic honeysuckle (Lonicera maackii, Caprifoliaceae) on the abundance and diversity of the dominant forest herbivores: woody plant-feeding Lepidoptera. We systematically surveyed understory caterpillars along transects in 19 forest fragments over multiple years in southwestern Ohio and evaluated how fragment area, isolation, tree diversity, invasion by honeysuckle and interactions among these factors influence species richness, diversity and abundance. We found strong seasonal variation in caterpillar communities, which responded differently to fragmentation and invasion. Abundance and richness increased with fragment area, but these effects were mitigated by high levels of honeysuckle, tree diversity, landscape forest cover, and large recent changes in area. Honeysuckle infestation was generally associated with decreased caterpillar abundance and diversity, but these effects were strongly dependent on other fragment traits. Effects of honeysuckle on abundance were moderated when fragment area, landscape forest cover and tree diversity were high. In contrast, negative effects of honeysuckle invasion on caterpillar diversity were most pronounced in fragments with high tree diversity and large recent increases in area. Our results illustrate the complex interdependencies of habitat fragmentation, plant diversity and plant invasion in their effects on primary consumers and emphasize the need to consider these processes in concert to understand the consequences of anthropogenic habitat change for biodiversity.

  6. Validation of chemical analyses of atmospheric deposition in forested European sites

    Directory of Open Access Journals (Sweden)

    Erwin ULRICH

    2005-08-01

    Full Text Available Within the activities of the Integrated Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests and of the EU Regulation 2152/2003, a Working Group on Quality Assurance/Quality Control of analyses has been created to assist the participating laboratories in the analysis of atmospheric deposition, soil and soil solution, and leaves/needles. As part of the activity of the WG, this study is a statistical analysis in the field of water analysis of chemical concentrations and relationships between ions, and between conductivity and ions for different types of samples (bulk or wet-only samples, throughfall, stemflow considered in forest studies. About 5000 analyses from seven laboratories were used to establish relationships representative of different European geographic and climatic situations, from northern Finland to southern Italy. Statistically significant differences between the relationships obtained from different types of solutions, interacting with different types of vegetation (throughfall and stemflow samples, broad-leaved trees and conifers and with varying influence of marine salt were tested. The ultimate aim is to establish general relationships between ions, and between conductivity and ions, with relative confidence limits, which can be used as a comparison with those established in single laboratories. The use of such techniques is strongly encouraged in the ICPF laboratories to validate single chemical analyses, to be performed when it is still possible to replicate the analysis, and as a general overview of the whole set of analyses, to obtain an indication of the laboratory performance on a long-term basis.

  7. Impacts of Drought Legacies on Tree Demography and Successional Trajectories of Tropical Forests

    Science.gov (United States)

    Uriarte, M.; Chazdon, R.; Boukili, V.

    2015-12-01

    Regenerating tropical forests account for 70% of all remaining tropical forest cover and 50% of the terrestrial carbon sink. Despite the importance of successional vegetation in tropical regions for global climate, how inter-annual climate variability influences successional trajectories and biomass accumulation remains poorly understood. Lagged effects of climate extremes on tropical tree demography and successional trajectories represent one key uncertainty. We couple 15 years of climate records and tree growth and survival data with functional trait information for 172 tree species to parameterize Stochastic Antecedent Models (SAMs) of lagged effects of drought on tree demography in second-growth tropical forests in Costa Rica. We also quantify how these legacies influence successional trajectories and biomass accumulation. Drought legacies on tree growth were particularly marked for species with high Specific Leaf Area and low wood density. These legacies led to elevated rates of tree mortality, particularly for large (>10 cm in diameter) up to 4 years after the occurrence of extreme droughts. Simulations of successional trajectories using immediate and lagged drought effects demonstrate that lagged effects lead to shifts in successional trajectories and substantial losses in biomass accumulation.

  8. Natural tree collectives of pure oriental spruce [Picea orientalis (L.) Link] on mountain forests in Turkey.

    Science.gov (United States)

    Ucler, Ali Omer; Yucesan, Zafer; Demirci, Ali; Yavuz, Hakki; Oktan, Ercan

    2007-04-01

    Distribution area of oriental spruce [Picea orientalis (L.) Link.] in the world is only in the north-east of Turkey and Caucasian. Because of being the semi monopoly tree with respect to its distribution and representing the upper forest line, it is necessary to analyse, evaluate and model the stand structures of oriental spruce forests in Turkey. In this research, some sampling plots were selected in timberline and treeline in the subalpine forest zone in Turkey. In these sampling plots some information about occurrence and development of the tree collectives was obtained. A total of 12 sampling plots (6 in timberline and 6 of them in treeline) were studied and horizontal and vertical stand profiles were obtained, while number of trees ranges between 2-86 in the tree collectives in treeline and in timberline 3-12. According to this, area per tree in treeline and in timberline is determined as 1.02 m2 and 3.75 m2 on an average respectively. Mean age of trees to reach breast height is 43 years in treeline sampling plots and 22 years in timberline sampling plots. According to the ratio of h (mean height) / d1.30 (diameter at breast height), stand stability values were calculated and it was determined if the stands were stable on the basis of the sampling plots. Stability values of the sampling plots changed between 33 and 75.

  9. The interrelationship of mycophagous small mammals and ectomycorrhizal fungi in primeval, disturbed and managed Central European mountainous forests.

    Science.gov (United States)

    Schickmann, Susanne; Urban, Alexander; Kräutler, Katharina; Nopp-Mayr, Ursula; Hackländer, Klaus

    2012-10-01

    Small forest dwelling mammals are considered to be major consumers and vectors of hypogeous ectomycorrhizal (ECM) fungi, which have lost the ability of active spore discharge. Fungal spore dispersal by mycophagy is deemed an important process involved in forest regeneration, resilience and vitality, primarily based on evidence from Australia and the Pacific Northwestern USA, but is poorly known for Central European mountainous forests thus far. Small mammal mycophagy was investigated by live trapping and microscopical analysis of faecal samples. All small mammal species recorded (Myodes glareolus, Microtus agrestis, Pitymys subterraneus, Apodemus spp., Glis glis, Sorex spp.) had ingested spores of ECM fungi, albeit in varying amounts. My. glareolus was found to be the most important vector of ECM fungal spores, both in quantity and diversity. Species of the genus Sorex seem to play a hitherto underestimated role as dispersers of fungal spores. Glis glis is likely to be an important vector owing to its large home range. Hypogeous ECM basidiomycetes accounted for most spores found in the faecal samples. The frequency of various genera of hypogeous ECM ascomycetes and ECM epigeous fungi was much lower. Comparison with null models indicated a non-random structure of the mycophagy network similar to other mutualistic bipartite networks. Mycophagy can be considered (1) to contribute to nutrition of small forest mammals, (2) to play a pivotal role for forest regeneration and functioning by providing mycorrhizal inoculum to tree seedlings and (3) to be vital for reproduction and diversity of the still poorly known hypogeous fungi.

  10. Drought stress, growth, and nonstructural carbohydrate dynamics of pine trees in a semi-arid forest

    Science.gov (United States)

    Klein, Tamir; Yakir, Dan; Hoch, Günter

    2014-05-01

    • In trees under prolonged drought, both carbon uptake (C source) and growth (C sink) typically decrease. This correlation raises two important questions: (1) to what degree is tree growth limited by C availability; and (2) Is growth limited by concurrent C storage (e.g. as nonstructural carbohydrates, NSC). • To test the relationships between drought, growth, and C reserves, we monitored the changes in NSC levels and constructed stem growth chronologies of Pinus halepensis trees of three drought stress levels growing in Yatir forest, Israel, at the dry limit of forest existence. • Moderately stressed and stressed trees showed 37% and 21% of the stem growth of healthy trees in 2012; 71% and 31% of the sap flux density; and 79% and 66% of the final needle length. In spite of these large reductions, both starch and soluble sugars concentrations in branches of these trees were similar in all trees throughout the dry season (2-4% dry mass). At the same time the root starch concentrations of moderately stressed and stressed trees were 47% and 58% of that of healthy trees, but never below 2% d.m. • Our results suggest that the drought-induced growth reduction is associated with a general C shortage, rather than competition with concurrent C storage. The relatively small effect of drought stress level on NSC dynamics, the maintenance of a 2% d.m. starch, and the continued sap flow indicate that a whole-tree C starvation is not likely to occur in these trees growing at the edge of the desert. Special request: If the abstract is not accepted for presentation in this session, please consider for presentation in session BG2.11 Plant traits and biogeochemical cycles. Thank you.

  11. Reconstructing Above Ground Forest Biomass Increment and Uncertainty Using Tree-ring Data

    Science.gov (United States)

    Dawson, A.; Paciorek, C. J.; Moore, D. J.; Pedersen, N.; Barker Plotkin, A.; Hessl, A. E.; Dye, A.; Bishop, D. A.; Alexander, M. R.; McLachlan, J. S.

    2015-12-01

    In a changing terrestrial climate, it is becoming increasingly important to be able to quantify Earth systems cycles, including thecarbon cycle. Atmospheric concentrations of carbon dioxide continue toincrease as a result of anthropogenic activity, but less is understood about how forest systems will affect the carbon cycle. In practice, it is difficult to measure carbon flux in a forest system. Flux towers, satellite and remote sensing methods, and dynamic vegetation models have been used to quantify current and future forest net primary productivity. Tree rings provide us with information about forest carbon storage in the past, and have been used to reconstruct above ground biomass increment (aBI). However, uncertainty from measurement error, assumptions about tree architecture including circular stems and diameter-volume relationships, and the fading record - the challenge of quantifying the growth of previously live trees - are often not accounted for. As a first step towards reconstructing aBI and its uncertainty, we develop a tree ring sampling protocol and a Bayesian hierarchical model toestimate aBI while accounting for measurement and architecture uncertainty. Tree-ring and repeated census plot data have been collected from several sites using a protocol that allows us toquantify growth dependence across trees in a local area. We also use multiple cores per tree to investigate the number of cores needed to reduce uncertainty from the assumption of stem circularity. For short-time-scale reconstructions, we avoid the fading record issue by coring dead trees and co-locating tree-ring data with censuses, thus avoiding having to make assumptions about stand density andmortality. We also statistically investigate the importance of including census data and of coring dead trees to quantify how uncertainty and bias are affected as we go back further in time. Preliminary results show that the model is able to estimate yearly variation in aBI well for many decades

  12. Estimating the number of tree species in forest populations using current vegetation survey and forest inventory and analysis approximation plots and grid intensities

    Science.gov (United States)

    Hans T. Schreuder; Jin-Mann S. Lin; John Teply

    2000-01-01

    We estimate number of tree species in National Forest populations using the nonparametric estimator. Data from the Current Vegetation Survey (CVS) of Region 6 of the USDA Forest Service were used to estimate the number of tree species with a plot close in size to the Forest Inventory and Analysis (FIA) plot and the actual CVS plot for the 5.5 km FIA grid and the 2.7 km...

  13. DO3SE modelling of soil moisture to determine ozone flux to forest trees

    Directory of Open Access Journals (Sweden)

    M. Schaub

    2012-06-01

    Full Text Available The DO3SE (Deposition of O3 for Stomatal Exchange model is an established tool for estimating ozone (O3 deposition, stomatal flux and impacts to a variety of vegetation types across Europe. It has been embedded within the EMEP (European Monitoring and Evaluation Programme photochemical model to provide a policy tool capable of relating the flux-based risk of vegetation damage to O3 precursor emission scenarios for use in policy formulation. A key limitation of regional flux-based risk assessments has been the assumption that soil water deficits are not limiting O3 flux due to the unavailability of evaluated methods for modelling soil water deficits and their influence on stomatal conductance (gsto, and subsequent O3 flux. This paper describes the development and evaluation of a method to estimate soil moisture status and its influence on gsto for a variety of forest tree species. This DO3SE soil moisture module uses the Penman-Monteith energy balance method to drive water cycling through the soil-plant-atmosphere system and empirical data describing gsto relationships with pre-dawn leaf water status to estimate the biological control of transpiration. We trial four different methods to estimate this biological control of the transpiration stream, which vary from simple methods that relate soil water content or potential directly to gsto, to more complex methods that incorporate hydraulic resistance and plant capacitance that control water flow through the plant system. These methods are evaluated against field data describing a variety of soil water variables, gsto and transpiration data for Norway spruce (Picea abies, Scots pine (Pinus sylvestris, birch (Betula pendula, aspen (Populus tremuloides, beech (Fagus sylvatica and holm oak (Quercus ilex collected from ten sites across Europe and North America. Modelled estimates of these variables show consistency with observed data when applying the simple empirical methods, with the timing and

  14. Does biodiversity make a difference? Relationships between species richness, evolutionary diversity, and aboveground live tree biomass across US forests

    Science.gov (United States)

    Kevin M. Potter; Christopher W. Woodall

    2014-01-01

    Biodiversity conveys numerous functional benefits to forested ecosystems, including community stability and resilience. In the context of managing forests for climate change mitigation/adaptation, maximizing and/or maintaining aboveground biomass will require understanding the interactions between tree biodiversity, site productivity, and the stocking of live trees....

  15. How fast will trees die? A transition matrix model of ash decline in forest stands infested by emerald ash borer

    Science.gov (United States)

    Kathleen S. Knight; Robert P. Long; Joanne Rebbeck; Annemarie Smith; Kamal Gandhi; Daniel A. Herms

    2008-01-01

    We recorded Fraxinus spp. tree health and other forest stand characteristics for 68 plots in 21 EAB-infested forest stands in Michigan and Ohio in 2005 and 2007. Fraxinus spp. were a dominant component of these stands, with more than 900 ash trees (including Fraxinus americana, Fraxinus pennsylvanica, Fraxinus profunda...

  16. Estimating individual tree mid- and understory rank-size distributions from airborne laser scanning in semi-arid forests

    Science.gov (United States)

    Tyson L. Swetnam; Donald A. Falk; Ann M. Lynch; Stephen R. Yool

    2014-01-01

    Limitations inherent to airborne laser scanning (ALS) technology and the complex sorting and packing relationships of forests complicate accurate remote sensing of mid- and understory trees, especially in denser forest stands. Self-similarities in rank-sized individual tree distributions (ITD), e.g. bole diameter or height, are a well-understood property of natural,...

  17. Regeneration in windthrow areas in hemiboreal forests: the influence of microsite on the height growths of different tree species

    Science.gov (United States)

    F. Vodde; K. Jõgiste; L. Gruson; T. Ilisson; K. Köster; J.A. Stanturf

    2010-01-01

    Natural regeneration of windthrow areas is an important issue when planning forestry measures after forest disturbances. Seedling recruitment was investigated in storm-damaged hemiboreal mixed forests in eastern Estonia. The establishment and growth of seedlings from natural regeneration was registered for tree species in soil pits and in mounds of uprooted trees in...

  18. Project CAPTURE: using forest inventory and analysis data to prioritize tree species for conservation, management, and restoration

    Science.gov (United States)

    Kevin M. Potter; Barbara S. Crane; William W. Hargrove

    2015-01-01

    A variety of threats, most importantly climate change and insect and disease infestation, will increase the likelihood that forest tree species could experience population-level extirpation or species-level extinction during the next century. Project CAPTURE (Conservation Assessment and Prioritization of Forest Trees Under Risk of Extirpation) is a cooperative effort...

  19. Feasibility of high-density climate reconstruction based on Forest Inventory and Analysis (FIA) collected tree-ring data

    Science.gov (United States)

    R. Justin DeRose; Shih-Yu Wang; John D. Shaw

    2013-01-01

    This study introduces a novel tree-ring dataset, with unparalleled spatial density, for use as a climate proxy. Ancillary Douglas fir and pinyon pine tree-ring data collected by the U.S. Forest Service Forest Inventory and Analysis Program (FIA data) were subjected to a series of tests to determine their feasibility as climate proxies. First, temporal coherence between...

  20. Tree survival and maximum density of planted forests – Observations from South African spacing studies

    Directory of Open Access Journals (Sweden)

    Klaus v. Gadow

    2014-10-01

    Full Text Available Background Among the most important aspects of risk and hazard studies relating to forest ecosystems are maximum forest density and density-dependent tree survival. Methods Long-term observations about the maximum density of unthinned Pinus patula and P. elliottii field plots based on the Correlated Curve Trend (CCT spacing studies which were established almost 8 decades ago by O’Connor (Forest Research with Special Reference to Planting Distances and Thinning, 1935 in South Africa. Three specific approaches were introduced for analysing maximum density and tree survival, namely the ‘limiting line’, Nilson’s sparsity and tree survival with the Weibull function. Results The main results are: a Maximum densities differ greatly among the two species grown on the same site and within the same species grown on different sites; it is possible to relate these differences to site index in both species. b The relationship between the quadratic mean diameter and the minimum average spacing of surviving trees (known as Nilson’s Sparsity appears to be surprisingly similar in both species. c An analysis of tree survival in response to different initial planting espacements shows that the Weibull survival function parameters can be estimated if the initial planting density is known. This result is presented for each of the eight large experiments used in this study. Conclusions This study contributes to a better understanding of tree survival and maximum density which are the key factors required for estimating risk and uncertainty. The risk of tree mortality is not constant, but varies with tree species, planting density, tree age and growing site. For estimating that risk, therefore, continuous long-term observation on different sites and with varying planting densities, as provided by the unthinned CCT series, are essential.

  1. Extracting coherent tree-ring climatic signals across spatial scales from extensive forest inventory data.

    Science.gov (United States)

    Duchesne, Louis; D'Orangeville, Loïc; Ouimet, Rock; Houle, Daniel; Kneeshaw, Daniel

    2017-01-01

    Increasing access to extensively replicated and broadly distributed tree-ring collections has led to a greater use of these large data sets to investigate climate forcing on tree growth. However, the number of chronologies added to large accessible databases is declining and few are updated, while chronologies are often sparsely distributed and are more representative of marginal growing environments. On the other hand, National Forest Inventories (NFI), although poorly replicated at the plot level as compared to classic dendrochronological sampling, contain a large amount of tree-ring data with high spatial density designed to be spatially representative of the forest cover. We propose an a posteriori approach to validating tree-ring measurements and dating, selecting individual tree-ring width time series, and building average chronologies at various spatial scales based on an extensive collection of ring width measurements of nearly 94,000 black spruce trees distributed over a wide area and collected as part of the NFI in the province of Quebec, Canada. Our results show that reliable signals may be derived at various spatial scales (from 37 to 583,000 km2) from NFI increment core samples. Signals from independently built chronologies are spatially coherent with each other and well-correlated with independent reference chronologies built at the stand level. We thus conclude that tree-ring data from NFIs provide an extraordinary opportunity to strengthen the spatial and temporal coverage of tree-ring data and to improve coordination with other contemporary measurements of forest growth to provide a better understanding of tree growth-climate relationships over broad spatial scales.

  2. Size-specific tree mortality varies with neighbourhood crowding and disturbance in a Montane Nothofagus forest.

    Directory of Open Access Journals (Sweden)

    Jennifer M Hurst

    Full Text Available Tree mortality is a fundamental process governing forest dynamics, but understanding tree mortality patterns is challenging because large, long-term datasets are required. Describing size-specific mortality patterns can be especially difficult, due to few trees in larger size classes. We used permanent plot data from Nothofagus solandri var. cliffortioides (mountain beech forest on the eastern slopes of the Southern Alps, New Zealand, where the fates of trees on 250 plots of 0.04 ha were followed, to examine: (1 patterns of size-specific mortality over three consecutive periods spanning 30 years, each characterised by different disturbance, and (2 the strength and direction of neighbourhood crowding effects on size-specific mortality rates. We found that the size-specific mortality function was U-shaped over the 30-year period as well as within two shorter periods characterised by small-scale pinhole beetle and windthrow disturbance. During a third period, characterised by earthquake disturbance, tree mortality was less size dependent. Small trees (<20 cm in diameter were more likely to die, in all three periods, if surrounded by a high basal area of larger neighbours, suggesting that size-asymmetric competition for light was a major cause of mortality. In contrast, large trees (≥ 20 cm in diameter were more likely to die in the first period if they had few neighbours, indicating that positive crowding effects were sometimes important for survival of large trees. Overall our results suggest that temporal variability in size-specific mortality patterns, and positive interactions between large trees, may sometimes need to be incorporated into models of forest dynamics.

  3. Towards a sampling strategy for the assessment of forest condition at European level: combining country estimates.

    Science.gov (United States)

    Travaglini, Davide; Fattorini, Lorenzo; Barbati, Anna; Bottalico, Francesca; Corona, Piermaria; Ferretti, Marco; Chirici, Gherardo

    2013-04-01

    A correct characterization of the status and trend of forest condition is essential to support reporting processes at national and international level. An international forest condition monitoring has been implemented in Europe since 1987 under the auspices of the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests). The monitoring is based on harmonized methodologies, with individual countries being responsible for its implementation. Due to inconsistencies and problems in sampling design, however, the ICP Forests network is not able to produce reliable quantitative estimates of forest condition at European and sometimes at country level. This paper proposes (1) a set of requirements for status and change assessment and (2) a harmonized sampling strategy able to provide unbiased and consistent estimators of forest condition parameters and of their changes at both country and European level. Under the assumption that a common definition of forest holds among European countries, monitoring objectives, parameters of concern and accuracy indexes are stated. On the basis of fixed-area plot sampling performed independently in each country, an unbiased and consistent estimator of forest defoliation indexes is obtained at both country and European level, together with conservative estimators of their sampling variance and power in the detection of changes. The strategy adopts a probabilistic sampling scheme based on fixed-area plots selected by means of systematic or stratified schemes. Operative guidelines for its application are provided.

  4. Selective logging in tropical forests decreases the robustness of liana–tree interaction networks to the loss of host tree species

    Science.gov (United States)

    Magrach, Ainhoa; Senior, Rebecca A.; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F.; Santamaria, Luis; Edwards, David P.

    2016-01-01

    Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the ‘health’ and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana–tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of ‘extinction debt’. PMID:26936241

  5. Selective logging in tropical forests decreases the robustness of liana-tree interaction networks to the loss of host tree species.

    Science.gov (United States)

    Magrach, Ainhoa; Senior, Rebecca A; Rogers, Andrew; Nurdin, Deddy; Benedick, Suzan; Laurance, William F; Santamaria, Luis; Edwards, David P

    2016-03-16

    Selective logging is one of the major drivers of tropical forest degradation, causing important shifts in species composition. Whether such changes modify interactions between species and the networks in which they are embedded remain fundamental questions to assess the 'health' and ecosystem functionality of logged forests. We focus on interactions between lianas and their tree hosts within primary and selectively logged forests in the biodiversity hotspot of Malaysian Borneo. We found that lianas were more abundant, had higher species richness, and different species compositions in logged than in primary forests. Logged forests showed heavier liana loads disparately affecting slow-growing tree species, which could exacerbate the loss of timber value and carbon storage already associated with logging. Moreover, simulation scenarios of host tree local species loss indicated that logging might decrease the robustness of liana-tree interaction networks if heavily infested trees (i.e. the most connected ones) were more likely to disappear. This effect is partially mitigated in the short term by the colonization of host trees by a greater diversity of liana species within logged forests, yet this might not compensate for the loss of preferred tree hosts in the long term. As a consequence, species interaction networks may show a lagged response to disturbance, which may trigger sudden collapses in species richness and ecosystem function in response to additional disturbances, representing a new type of 'extinction debt'. © 2016 The Author(s).

  6. Biogeochemical modelling vs. tree-ring data - comparison of forest ecosystem productivity estimates

    Science.gov (United States)

    Zorana Ostrogović Sever, Maša; Barcza, Zoltán; Hidy, Dóra; Paladinić, Elvis; Kern, Anikó; Marjanović, Hrvoje

    2017-04-01

    Forest ecosystems are sensitive to environmental changes as well as human-induce disturbances, therefore process-based models with integrated management modules represent valuable tool for estimating and forecasting forest ecosystem productivity under changing conditions. Biogeochemical model Biome-BGC simulates carbon, nitrogen and water fluxes, and it is widely used for different terrestrial ecosystems. It was modified and parameterised by many researchers in the past to meet the specific local conditions. In this research, we used recently published improved version of the model Biome-BGCMuSo (BBGCMuSo), with multilayer soil module and integrated management module. The aim of our research is to validate modelling results of forest ecosystem productivity (NPP) from BBGCMuSo model with observed productivity estimated from an extensive dataset of tree-rings. The research was conducted in two distinct forest complexes of managed Pedunculate oak in SE Europe (Croatia), namely Pokupsko basin and Spačva basin. First, we parameterized BBGCMuSo model at a local level using eddy-covariance (EC) data from Jastrebarsko EC site. Parameterized model was used for the assessment of productivity on a larger scale. Results of NPP assessment with BBGCMuSo are compared with NPP estimated from tree ring data taken from trees on over 100 plots in both forest complexes. Keywords: Biome-BGCMuSo, forest productivity, model parameterization, NPP, Pedunculate oak

  7. Regression tree modeling of forest NPP using site conditions and climate variables across eastern USA

    Science.gov (United States)

    Kwon, Y.

    2013-12-01

    As evidence of global warming continue to increase, being able to predict forest response to climate changes, such as expected rise of temperature and precipitation, will be vital for maintaining the sustainability and productivity of forests. To map forest species redistribution by climate change scenario has been successful, however, most species redistribution maps lack mechanistic understanding to explain why trees grow under the novel conditions of chaining climate. Distributional map is only capable of predicting under the equilibrium assumption that the communities would exist following a prolonged period under the new climate. In this context, forest NPP as a surrogate for growth rate, the most important facet that determines stand dynamics, can lead to valid prediction on the transition stage to new vegetation-climate equilibrium as it represents changes in structure of forest reflecting site conditions and climate factors. The objective of this study is to develop forest growth map using regression tree analysis by extracting large-scale non-linear structures from both field-based FIA and remotely sensed MODIS data set. The major issue addressed in this approach is non-linear spatial patterns of forest attributes. Forest inventory data showed complex spatial patterns that reflect environmental states and processes that originate at different spatial scales. At broad scales, non-linear spatial trends in forest attributes and mixture of continuous and discrete types of environmental variables make traditional statistical (multivariate regression) and geostatistical (kriging) models inefficient. It calls into question some traditional underlying assumptions of spatial trends that uncritically accepted in forest data. To solve the controversy surrounding the suitability of forest data, regression tree analysis are performed using Software See5 and Cubist. Four publicly available data sets were obtained: First, field-based Forest Inventory and Analysis (USDA

  8. Conversion of natural forest to managed forest plantations decreases tree resistance to prolonged droughts

    Science.gov (United States)

    Jean-Christophe Domec; John S. King; Eric Ward; A. Christopher Oishi; Sari Palmroth; Andrew Radecki; Dave M. Bell; Guofang Miao; Michael Gavazzi; Daniel M. Johnson; Steve G. McNulty; Ge Sun; Asko. Noormets

    2015-01-01

    Throughout the southern US, past forest management practices have replaced large areas of native forests with loblolly pine plantations and have resulted in changes in forest response to extreme weather conditions. However, uncertainty remains about the response of planted versus natural species to drought across the geographical range of these forests. Taking...

  9. One tree to link them all: a phylogenetic dataset for the European tetrapoda.

    Science.gov (United States)

    Roquet, Cristina; Lavergne, Sébastien; Thuiller, Wilfried

    2014-08-08

    Since the ever-increasing availability of phylogenetic informative data, the last decade has seen an upsurge of ecological studies incorporating information on evolutionary relationships among species. However, detailed species-level phylogenies are still lacking for many large groups and regions, which are necessary for comprehensive large-scale eco-phylogenetic analyses. Here, we provide a dataset of 100 dated phylogenetic trees for all European tetrapods based on a mixture of supermatrix and supertree approaches. Phylogenetic inference was performed separately for each of the main Tetrapoda groups of Europe except mammals (i.e. amphibians, birds, squamates and turtles) by means of maximum likelihood (ML) analyses of supermatrix applying a tree constraint at the family (amphibians and squamates) or order (birds and turtles) levels based on consensus knowledge. For each group, we inferred 100 ML trees to be able to provide a phylogenetic dataset that accounts for phylogenetic uncertainty, and assessed node support with bootstrap analyses. Each tree was dated using penalized-likelihood and fossil calibration. The trees obtained were well-supported by existing knowledge and previous phylogenetic studies. For mammals, we modified the most complete supertree dataset available on the literature to include a recent update of the Carnivora clade. As a final step, we merged the phylogenetic trees of all groups to obtain a set of 100 phylogenetic trees for all European Tetrapoda species for which data was available (91%). We provide this phylogenetic dataset (100 chronograms) for the purpose of comparative analyses, macro-ecological or community ecology studies aiming to incorporate phylogenetic information while accounting for phylogenetic uncertainty.

  10. Turbulence structure in a diabatically heated forest canopy composed of fractal Pythagoras trees

    Science.gov (United States)

    Schröttle, Josef; Dörnbrack, Andreas

    2013-06-01

    We investigate the turbulent flow through a heterogeneous forest canopy by high-resolution numerical modeling. For this purpose, a novel approach to model individual trees is implemented in our large-eddy simulation (LES). A group of sixteen fractal Pythagoras trees is placed in the computational domain and the tree elements are numerically treated as immersed boundaries. Our objective is to resolve the multiscale flow response starting at the diameter of individual tree elements up to the depth of the atmospheric surface layer. A reference run, conducted for the forest flow under neutral thermal stratification, produces physically meaningful turbulence statistics. Our numerical results agree quantitatively with data obtained from former field-scale LESs and wind tunnel experiments. Furthermore, the numerical simulations resolve vortex shedding behind individual branches and trunks as well as the integral response of the turbulent flow through the heterogeneous forest canopy. A focus is the investigation of the turbulence structure of the flow under stable thermal stratification and in response to the heating of the fractal tree crowns. For the stratified flows, statistical quantities, e.g. turbulent kinetic energy and vorticity, are presented and the turbulent exchange processes of momentum and heat are considered in detail. The onset and formation of coherent structures such as elevated shear layers above the diabatically heated forest canopy are analyzed. For the stably stratified flow, temperature ramps above the forest canopy were simulated in agreement with previous observations. Thermally driven vortices with a typical diameter of the canopy height were simulated when the tree crowns were diabatically heated. The impact of the coherent flow structures on the heat flux is investigated.

  11. Methane emissions and uptake in temperate and tropical forest trees on free-draining soils.

    Science.gov (United States)

    Welch, Bertie; Sayer, Emma; Siegenthaler, Andy; Gauci, Vincent

    2016-04-01

    Forests play an important role in the exchange of radiatively important gases with the atmosphere. Previous studies have shown that in both temperate and tropical wetland forests tree stems are significant sources of methane (CH4), yet little is known about trace greenhouse gas dynamics in free-draining soils that dominate global forested areas. We examined trace gas (CH4 and N2O) fluxes from both soils and tree stems in a lowland tropical forest on free-draining soils in Panama, Central America and from a deciduous woodland in the United Kingdom. The tropical field site was a long-term experimental litter manipulation experiment in the Barro Colorado Nature Monument within the Panama Canal Zone, fluxes were sampled over the dry to wet season transition (March-August) in 2014 and November 2015. Temperate fluxes were sampled at Wytham Woods, Oxfordshire, over 12 months from February 2015 to January 2016. Tree stem samples were collected via syringe from temporary chambers strapped to the trees (as per Siegenthaler et al. (2015)) and the soil fluxes were sampled from permanently installed collars inserted to a 3cm depth. We found that seasonality (precipitation) is a significant driver of changing soil exchange from methane uptake to emission at the Panama sites. Experimental changes to litter quantity only become significant when coupled with seasonal change. Seasonal variability is an important control of the fluxes at out temperate forest site with changes in temperature and soil water content leading to changes in soil and tree stem trace gas fluxes from Wytham Woods. Siegenthaler, A., Welch, B., Pangala, S. R., Peacock, M., and Gauci, V.: Technical Note: Semi-rigid chambers for methane gas flux measurements on tree-stems, Biogeosciences Discuss., 12, 16019-16048, doi:10.5194/bgd-12-16019-2015, 2015.

  12. The Importance of Large-Diameter Trees to Forest Structural Heterogeneity

    Science.gov (United States)

    Lutz, James A.; Larson, Andrew J.; Freund, James A.; Swanson, Mark E.; Bible, Kenneth J.

    2013-01-01

    Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥1 cm dbh, all 1,966 snags ≥10 cm dbh, and all shrub patches ≥2 m2. Basal area of the 26 woody species was 62.18 m2/ha, of which 61.60 m2/ha was trees and 0.58 m2/ha was tall shrubs. Large-diameter trees (≥100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P≤0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses. PMID:24376579

  13. Quantifying Tree and Soil Carbon Stocks in a Temperate Urban Forest in Northeast China

    Directory of Open Access Journals (Sweden)

    Hailiang Lv

    2016-09-01

    Full Text Available Society has placed greater focus on the ecological service of urban forests; however, more information is required on the variation of carbon (C in trees and soils in different functional forest types, administrative districts, and urban-rural gradients. To address this issue, we measured various tree and soil parameters by sampling 219 plots in the urban forest of the Harbin city region. Averaged tree and soil C stock density (C stocks per unit tree cover for Harbin city were 7.71 (±7.69 kg C·m−2 and 5.48 (±2.86 kg C·m−2, respectively. They were higher than those of other Chinese cities (Shenyang and Changchun, but were much lower than local natural forests. The tree C stock densities varied 2.3- to 3.2-fold among forest types, administrative districts, and ring road-based urban-rural gradients. In comparison, soil organic C (SOC densities varied by much less (1.4–1.5-fold. We found these to be urbanization-dependent processes, which were closely related to the urban-rural gradient data based on ring-roads and settlement history patterns. We estimated that SOC accumulation during the 100-year urbanization of Harbin was very large (5 to 14 thousand tons, accounting for over one quarter of the stored C in trees. Our results provide new insights into the dynamics of above- and below-ground C (especially in soil during the urbanization process, and that a city’s ability to provide C-related ecosystem services increases as it ages. Our findings highlight that urbanization effects should be incorporated into calculations of soil C budgets in regions subject to rapid urban expansion, such as China.

  14. [Biomass allometric equations of nine common tree species in an evergreen broadleaved forest of subtropical China].

    Science.gov (United States)

    Zuo, Shu-di; Ren, Yin; Weng, Xian; Ding, Hong-feng; Luo, Yun-jian

    2015-02-01

    Biomass allometric equation (BAE) considered as a simple and reliable method in the estimation of forest biomass and carbon was used widely. In China, numerous studies focused on the BAEs for coniferous forest and pure broadleaved forest, and generalized BAEs were frequently used to estimate the biomass and carbon of mixed broadleaved forest, although they could induce large uncertainty in the estimates. In this study, we developed the species-specific and generalized BAEs using biomass measurement for 9 common broadleaved trees (Castanopsis fargesii, C. lamontii, C. tibetana, Lithocarpus glaber, Sloanea sinensis, Daphniphyllum oldhami, Alniphyllum fortunei, Manglietia yuyuanensis, and Engelhardtia fenzlii) of subtropical evergreen broadleaved forest, and compared differences in species-specific and generalized BAEs. The results showed that D (diameter at breast height) was a better independent variable in estimating the biomass of branch, leaf, root, aboveground section and total tree than a combined variable (D2 H) of D and H (tree height) , but D2H was better than D in estimating stem biomass. R2 (coefficient of determination) values of BAEs for 6 species decreased when adding H as the second independent variable into D- only BAEs, where R2 value for S. sinensis decreased by 5.6%. Compared with generalized D- and D2H-based BAEs, standard errors of estimate (SEE) of BAEs for 8 tree species decreased, and similar decreasing trend was observed for different components, where SEEs of the branch decreased by 13.0% and 20.3%. Therefore, the biomass carbon storage and its dynamic estimates were influenced largely by tree species and model types. In order to improve the accuracy of the estimates of biomass and carbon, we should consider the differences in tree species and model types.

  15. 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

  16. Automatic Detection of Small Single Trees in the Forest-Tundra Ecotone Using Airborne Laser Scanning

    Directory of Open Access Journals (Sweden)

    Nadja Stumberg

    2014-10-01

    Full Text Available A large proportion of Norway’s land area is occupied by the forest-tundra ecotone. The vegetation of this temperature-sensitive ecosystem between mountain forest and the alpine zone is expected to be highly affected by climate change and effective monitoring techniques are required. For the detection of such small pioneer trees, airborne laser scanning (ALS has been proposed as a useful tool employing laser height data. The objective of this study was to assess the capability of an unsupervised classification for automated monitoring programs of small individual trees using high-density ALS data. Field and ALS data were collected along a 1500 km long transect stretching from northern to southern Norway. Different laser and tree height thresholds were tested in various combinations within an unsupervised classification of tree and nontree raster cells employing different cell sizes. Suitable initial cell sizes for the exclusion of large treeless areas as well as an optimal cell size for tree cell detection were determined. High rates of successful tree cell detection involved high levels of commission error at lower laser height thresholds, however, exceeding the 20 cm laser height threshold, the rates of commission error decreased substantially with a still satisfying rate of successful tree cell detection.

  17. Methane Production Explained Largely by Water Content in the Heartwood of Living Trees in Upland Forests

    Science.gov (United States)

    Wang, Zhi-Ping; Han, Shi-Jie; Li, Huan-Long; Deng, Feng-Dan; Zheng, Yan-Hai; Liu, Hai-Feng; Han, Xing-Guo

    2017-10-01

    Most forests worldwide are located in upland landscapes. Previous studies have mainly focused on ground methane (CH4) flux in upland forests, and living tree stem-based CH4 processes and fluxes are thus relatively poorly understood. This study investigated the relationship between CH4 concentration and water content in the heartwood of living trees in midtemperate, warm temperate, and subtropical upland forests and also measured seasonal changes of in situ stem CH4 flux and the CH4 concentration and water content in the heartwood of Populus davidiana Dode in a warm temperate upland forest. We found that approximately 4-13% of tree stems or approximately 8-31% of tree species had a substantial CH4 concentration of ≥10,000 μL L-1 in their heartwood across the three types of upland forests. The heartwood CH4 concentration was related to water content by a power function. A threshold of water content occurred beyond which CH4 was produced at high levels in the heartwood. The CH4 emissions from the breast height stems of P. davidiana ranged from 202.1 to 331.6 μg m-2 h-1 on a stem surface area basis during July-October 2016 and were significantly linearly correlated with the CH4 concentration or water content in the heartwood throughout the experimental period, but the linear correlation was not significant at daily and monthly scales. Temperature was not a limiting factor for CH4 production during July-October 2016, and thus, most of the CH4 production may be explained by water content in the heartwood of living trees in upland forests.

  18. Variation in phenolic root exudates and rhizosphere carbon cycling among tree species in temperate forest ecosystems

    Science.gov (United States)

    Zwetsloot, Marie; Bauerle, Taryn; Kessler, André; Wickings, Kyle

    2017-04-01

    Temperate forest tree species composition has been highly dynamic over the past few centuries and is expected to only further change under current climate change predictions. While aboveground changes in forest biodiversity have been widely studied, the impacts on belowground processes are far more challenging to measure. In particular, root exudation - the process through which roots release organic and inorganic compounds into the rhizosphere - has received little scientific attention yet may be the key to understanding root-facilitated carbon cycling in temperate forest ecosystems. The aim of this study was to analyze the extent by which tree species' variation in phenolic root exudate profiles influences soil carbon cycling in temperate forest ecosystems. In order to answer this question, we grew six temperate forest tree species in a greenhouse including Acer saccharum, Alnus rugosa, Fagus grandifolia, Picea abies, Pinus strobus, and Quercus rubra. To collect root exudates, trees were transferred to hydroponic growing systems for one week and then exposed to cellulose acetate strips in individual 800 mL jars with a sterile solution for 24 hours. We analyzed the methanol-extracted root exudates for phenolic composition with high-performance liquid chromatography (HPLC) and determined species differences in phenolic abundance, diversity and compound classes. This information was used to design the subsequent soil incubation study in which we tested the effect of different phenolic compound classes on rhizosphere carbon cycling using potassium hydroxide (KOH) traps to capture soil CO2 emissions. Our findings show that tree species show high variation in phenolic root exudate patterns and that these differences can significantly influence soil CO2 fluxes. These results stress the importance of linking belowground plant traits to ecosystem functioning. Moreover, this study highlights the need for research on root and rhizosphere processes in order to improve

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

    Science.gov (United States)

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

    2017-01-01

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

  20. Quantifying the Detrimental Impacts of Land-Use and Management Change on European Forest Bird Populations

    Science.gov (United States)

    Wade, Amy S. I.; Barov, Boris; Burfield, Ian J.; Gregory, Richard D.; Norris, Ken; Butler, Simon J.

    2013-01-01

    The ecological impacts of changing forest management practices in Europe are poorly understood despite European forests being highly managed. Furthermore, the effects of potential drivers of forest biodiversity decline are rarely considered in concert, thus limiting effective conservation or sustainable forest management. We present a trait-based framework that we use to assess the detrimental impact of multiple land-use and management changes in forests on bird populations across Europe. Major changes to forest habitats occurring in recent decades, and their impact on resource availability for birds were identified. Risk associated with these changes for 52 species of forest birds, defined as the proportion of each species' key resources detrimentally affected through changes in abundance and/or availability, was quantified and compared to their pan-European population growth rates between 1980 and 2009. Relationships between risk and population growth were found to be significantly negative, indicating that resource loss in European forests is an important driver of decline for both resident and migrant birds. Our results demonstrate that coarse quantification of resource use and ecological change can be valuable in understanding causes of biodiversity decline, and thus in informing conservation strategy and policy. Such an approach has good potential to be extended for predictive use in assessing the impact of possible future changes to forest management and to develop more precise indicators of forest health. PMID:23704997

  1. Will the CO2 fertilization effect in forests be offset by reduced tree longevity?

    Science.gov (United States)

    Bugmann, Harald; Bigler, Christof

    2011-02-01

    Experimental studies suggest that tree growth is stimulated in a greenhouse atmosphere, leading to faster carbon accumulation (i.e., a higher rate of gap filling). However, higher growth may be coupled with reduced longevity, thus leading to faster carbon release (i.e., a higher rate of gap creation). The net effect of these two counteracting processes is not known. We quantify this net effect on aboveground carbon stocks using a novel combination of data sets and modeling. Data on maximum growth rate and maximum longevity of 141 temperate tree species are used to derive a relationship between growth stimulation and changes in longevity. We employ this relationship to modify the respective parameter values of tree species in a forest succession model and study aboveground biomass in a factorial design of growth stimulation × reduced maximum longevity at multiple sites along a climate gradient from the cold to the dry treeline. The results show that (1) any growth stimulation at the tree level leads to a disproportionately small increase of stand biomass due to negative feedback effects, even in the absence of reduced longevity; (2) a reduction of tree longevity tends to offset the growth-related biomass increase; at the most likely value of reduced longevity, the net effect is very close to zero in most multi- and single-species simulations; and (3) when averaging the response across all sites to mimic a "landscape-level" response, the net effect is close to zero. Thus, it is important to consider ecophysiological responses with their linkage to demographic processes in forest trees if one wishes to avoid erroneous inference at the ecosystem level. We conclude that any CO(2) fertilization effect is quite likely to be offset by an associated reduction in the longevity of forest trees, thus strongly reducing the carbon mitigation potential of temperate forests.

  2. Tree Species Classification in Temperate Forests Using Formosat-2 Satellite Image Time Series

    Directory of Open Access Journals (Sweden)

    David Sheeren

    2016-09-01

    Full Text Available Mapping forest composition is a major concern for forest management, biodiversity assessment and for understanding the potential impacts of climate change on tree species distribution. In this study, the suitability of a dense high spatial resolution multispectral Formosat-2 satellite image time-series (SITS to discriminate tree species in temperate forests is investigated. Based on a 17-date SITS acquired across one year, thirteen major tree species (8 broadleaves and 5 conifers are classified in a study area of southwest France. The performance of parametric (GMM and nonparametric (k-NN, RF, SVM methods are compared at three class hierarchy levels for different versions of the SITS: (i a smoothed noise-free version based on the Whittaker smoother; (ii a non-smoothed cloudy version including all the dates; (iii a non-smoothed noise-free version including only 14 dates. Noise refers to pixels contaminated by clouds and cloud shadows. The results of the 108 distinct classifications show a very high suitability of the SITS to identify the forest tree species based on phenological differences (average κ = 0 . 93 estimated by cross-validation based on 1235 field-collected plots. SVM is found to be the best classifier with very close results from the other classifiers. No clear benefit of removing noise by smoothing can be observed. Classification accuracy is even improved using the non-smoothed cloudy version of the SITS compared to the 14 cloud-free image time series. However conclusions of the results need to be considered with caution because of possible overfitting. Disagreements also appear between the maps produced by the classifiers for complex mixed forests, suggesting a higher classification uncertainty in these contexts. Our findings suggest that time-series data can be a good alternative to hyperspectral data for mapping forest types. It also demonstrates the potential contribution of the recently launched Sentinel-2 satellite for

  3. Comparative analysis of harmonized forest area stimates for European countries

    DEFF Research Database (Denmark)

    Seebach, Lucia Maria; Strobl, P.; Miguel-Ayanz, J. San

    2011-01-01

    Harmonized forest area information provides an important basis for environmental modelling and policy-making at both national and international levels. Traditionally, this information has been provided by national forest inventory statistics but is now increasingly complemented with remote sensing...

  4. A System to Derive Optimal Tree Diameter Increment Models from the Eastwide Forest Inventory Data Base (EFIDB)

    Science.gov (United States)

    Don C. Bragg

    2002-01-01

    This article is an introduction to the computer software used by the Potential Relative Increment (PRI) approach to optimal tree diameter growth modeling. These DOS programs extract qualified tree and plot data from the Eastwide Forest Inventory Data Base (EFIDB), calculate relative tree increment, sort for the highest relative increments by diameter class, and...

  5. Dendrometric measurements reveal stages leading to tree mortality in a semiarid pine forest

    Science.gov (United States)

    Tatarinov, Fyodor; Preisler, Yakir; Klein, Tamir; Rotenberg, Eyal; Yakir, Dan

    2017-04-01

    Increasing frequency and intensity of climatic extreme events, such as droughts may lead to increasing vulnerability of forests, especially in semi-arid regions. In the spring of 2016 mortality was observed among trees used for sap flow (SF) and dendrometry measurements in the semi-arid Fluxnet pine forest site of Yatir in Israel (280mm annual mean precipitation). This was accompanied by bark-beetle attack, and with visual drying of needles starting in April 2016. Comparative analysis of dendrometry and sap flux (SF) measurements in 31 trees of which 7 died and 24 survived permitted identification of the stages leading to tree mortality. Distinction between dying and surviving trees was identified in the dendrometric measurements from Nov. 2015, about five months before visual mortality signs: First, clear decline in diameter (DBH) was observed in all dying trees, whereas DBH of living trees remained constant until the first rain in January 2016 followed by growth. Second, the diurnal patterns in DBH showed a gradual shift of the diurnal DBH maximum from noon-time to early morning from the summer of 2015 to the spring of 2016 in surviving trees, whereas in dying trees it remained stable around noontime. Third, the diurnal swelling/shrinkage dynamics, assumed to reflect water use and storage dynamics, showed clear decline in magnitude, down to near zero, in the dying trees while regular daily cycle continued in the surviving trees. In September 2015 Shoot measurements showed midnight minimum of leaf water potential, lower than in living trees (-4.5 vs. -3.6 MPa respectively). Sap flow measurements were not sufficiently sensitive during the non-active season (fall and early winter) and indicated changes only after the first rain in January 2016. At this time, SF showed dramatic increase in SF with typical midday maximum in the surviving trees, whereas in dying trees SF remained low and irregular. The results show that indicators of mortality can be detected at least

  6. 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.

  7. Are tall trees more sensitive to prolonged drought in tropical per-humid forests?

    Science.gov (United States)

    Schuldt, Bernhard; Horna, Viviana; Leuschner, Christoph

    2010-05-01

    Seasonality of water flux was investigated for common tree species of a Central Sulawesi pre-montane perhumid forest located in the Lore Lindu National Park. Trees were exposed to reduced soil water levels under a rainfall exclusion experiment (Sulawesi Throughfall Displacement Experiment, STD), to simulate drought effects and to monitor species-specific short-term responses to extended water stress. Several climate scenarios predict more frequent occurrence of ENSO droughts with increasing severity induced by global warming. Detailed assessments of the ecological consequences of droughts in perhumid forests are scarce and knowledge whether and how these ecosystems are adapted to severe droughts is limited. Key research questions were: (1) how do tall rainforest trees cope with long pathways under low evaporative demand, (2) how sensitive are trees from tropical perhumid forests and how do they acclimate to drought-stress and 3) does wood density determine the drought sensitivity of perhumid forest trees? From June 2007 until October 2009 we monitored 95 trees from 8 common tree species. Half of them were located under the STD Experiment and the other half in control areas. We used the constant heated method to continuously monitor stem xylem flux density and conduct parallel measurements of xylem anatomy and hydraulic conductivity in twigs, stems and roots. After almost 22 months of experimental drought only 25% of xylem flux density reduction was observed in the experimental trees. But the reaction to water stress was species-specific and in some species xylem flux went down to 50 % compared to the individuals located at the control plots. Wood density did not correlate with any hydraulic measurement, but anatomy and hydraulic architecture observations showed a positive correlation between xylem conductivity and vessel size with tree height. These results reveal a well adapted hydraulic system of tall canopy trees allowing for highly efficient water flow under

  8. One Tree to Link Them All: A Phylogenetic Dataset for the European Tetrapoda

    OpenAIRE

    Roquet, Cristina; Lavergne, S?bastien; Thuiller, Wilfried

    2014-01-01

    Since the ever-increasing availability of phylogenetic informative data, the last decade has seen an upsurge of ecological studies incorporating information on evolutionary relationships among species. However, detailed species-level phylogenies are still lacking for many large groups and regions, which are necessary for comprehensive large-scale eco-phylogenetic analyses. Here, we provide a dataset of 100 dated phylogenetic trees for all European tetrapods based on a mixture of supermatrix a...

  9. European perspective on the developments of planted forests, including projections to 2065

    NARCIS (Netherlands)

    Nabuurs, G.J.; Schelhaas, M.; Orazio, C.; Hengeveld, G.M.; Tome, N.; Farrell, E.P.

    2014-01-01

    Background: The 27 countries in the European Union have a combined total of 177 million ha of forested and other wooded land. These are mainly characterised as semi-natural, multi-functional forests. Only about 13 million ha are characterised as plantationsi, although an additional 47 million ha are

  10. Assessment of the water balance of European forests: a model study

    NARCIS (Netherlands)

    Salm, van der C.; Reinds, G.J.; Vries, de W.

    2004-01-01

    As part of the UN-ECE Intensive Monitoring Program, data on precipitation, throughfall and soil solution concentrations are measured on a regular basis in approximately 300 forest stands. These data were used to construct element budgets for European forests. To construct such budgets drainage

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

    NARCIS (Netherlands)

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

    2014-01-01

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

  12. Phylogenetic responses of forest trees to global change.

    Directory of Open Access Journals (Sweden)

    John K Senior

    Full Text Available In a rapidly changing biosphere, approaches to understanding the ecology and evolution of forest species will be critical to predict and mitigate the effects of anthropogenic global change on forest ecosystems. Utilizing 26 forest species in a factorial experiment with two levels each of atmospheric CO2 and soil nitrogen, we examined the hypothesis that phylogeny would influence plant performance in response to elevated CO2 and nitrogen fertilization. We found highly idiosyncratic responses at the species level. However, significant, among-genetic lineage responses were present across a molecularly determined phylogeny, indicating that past evolutionary history may have an important role in the response of whole genetic lineages to future global change. These data imply that some genetic lineages will perform well and that others will not, depending upon the environmental context.

  13. Trees, poverty and targets: Forests and the Millennium Development Goals

    Energy Technology Data Exchange (ETDEWEB)

    Myers, James

    2007-04-15

    Where are the forests in the MDGs? When players in the forestry world get together they are good at setting goals. They are a good match for the political leaders that gave us the Millennium Development Goals (MDGs). Since the 1980s there has been a proliferation of international dialogues dealing with forests and, a bit like the football World Cup, every four years or so they come up with a feast of goals. If forestry goals were all we needed to make progress, then sustainable and pro-poor forestry would have long since become a worldwide reality. Of course, implementation still lags well behind aspiration, but at least there is now a considerable body of international knowledge and agreement on how forests can contribute to development.

  14. Carbon balance gradient in European forests: Interpreting EUROFLUX

    Energy Technology Data Exchange (ETDEWEB)

    Piovesan, G. [Univ. of Tuscia, Viterbo (Italy). Dept. of Forest Science; Adams, J.M. [Univ. of Adelaide, SA (Australia). Dept. of Environmental and Geographical Studies

    2000-12-01

    A latitudinal trend in forest carbon uptake across Europe has been described by the EUROFLUX group, suggesting a considerable uptake in Italian Quercus ilex, Fagus sylvatica and Picea abies forests while a much lower C sink is reported in Scandinavian Picea abies forest. These results are discussed on the basis of the existing literature, and considered to be open to considerable doubt.

  15. Forest service contributions to the national land cover database (NLCD): Tree Canopy Cover Production

    Science.gov (United States)

    Bonnie Ruefenacht; Robert Benton; Vicky Johnson; Tanushree Biswas; Craig Baker; Mark Finco; Kevin Megown; John Coulston; Ken Winterberger; Mark. Riley

    2015-01-01

    A tree canopy cover (TCC) layer is one of three elements in the National Land Cover Database (NLCD) 2011 suite of nationwide geospatial data layers. In 2010, the USDA Forest Service (USFS) committed to creating the TCC layer as a member of the Multi-Resolution Land Cover (MRLC) consortium. A general methodology for creating the TCC layer was reported at the 2012 FIA...

  16. Genomic science provides new insights into the biology of forest trees

    Science.gov (United States)

    Andrew Groover

    2015-01-01

    Forest biology is undergoing a fundamental change fostered by the application of genomic science to longstanding questions surrounding the evolution, adaptive traits, development, and environmental interactions of tree species. Genomic science has made major technical leaps in recent years, most notably with the advent of 'next generation sequencing' but...

  17. Forest fire in the central Himalaya: climate and recovery of trees

    Science.gov (United States)

    Sharma, Subrat; Rikhari, H. C.

    A forest fire event is influenced by climatic conditions and is supported by accumulation of fuel on forest floor. After forest fire, photosynthetically active solar radiation was reduced due to accumulation of ash and dust particles in atmosphere. Post-fire impacts on Quercus leucotrichophora, Rhododendron arboreum and Lyonia ovalifolia in a broadleaf forest were analysed after a wild fire. Bark depth damage was greatest for L. ovalifolia and least for Q. leucotrichophora. Regeneration of saplings was observed for all the tree species through sprouting. Epicormic recovery was observed for the trees of all the species. Young trees of Q. leucotrichophora (<40 cm circumference at breast height) were susceptible to fire as evident by the lack of sprouting. Under-canopy tree species have a high potential for recovery as evident by greater length and diameter of shoots and numbers of buds and leaves per shoot than canopy species. Leaf area, leaf moisture and specific leaf area were greater in the deciduous species, with few exceptions, than in evergreen species.

  18. Constraints on physiological function associated with branch architecture and wood density in tropical forest trees

    Science.gov (United States)

    Frederick C. Meinzer; Paula I. Campanello; Jean-Christophe Domec; M. Genoveva Gatti; Guillermo Goldstein; Randol Villalobos-Vega; David R. Woodruff

    2008-01-01

    This study examined how leaf and stem functional traits related to gas exchange and water balance scale with two potential proxies for tree hydraulic architecture: the leaf area:sapwood area ratio (AL:AS) and wood density (W). We studied the upper crowns of individuals of 15 tropical forest...

  19. Assessing tree species assemblages in highly disturbed Puerto Rican karst landscapes using forest inventory data.

    Science.gov (United States)

    Thomas James Brandeis

    2006-01-01

    Tree species assemblages described by landscape-scale forest inventory data both agreed and differed from those described by intensive, site specific studies in Puerto Rico’s highly disturbed northern karst belt. Species assemblages found on hill tops (typified by Tabebuia heterophylla or Bursera simaruba with Coccoloba diversifolia, Licaria parvifolia, and Drypetes...

  20. Climatic correlates of tree mortality in water- and energy-limited forests.

    Directory of Open Access Journals (Sweden)

    Adrian J Das

    Full Text Available Recent increases in tree mortality rates across the western USA are correlated with increasing temperatures, but mechanisms remain unresolved. Specifically, increasing mortality could predominantly be a consequence of temperature-induced increases in either (1 drought stress, or (2 the effectiveness of tree-killing insects and pathogens. Using long-term data from California's Sierra Nevada mountain range, we found that in water-limited (low-elevation forests mortality was unambiguously best modeled by climatic water deficit, consistent with the first mechanism. In energy-limited (high-elevation forests deficit models were only equivocally better than temperature models, suggesting that the second mechanism is increasingly important in these forests. We could not distinguish between models predicting mortality using absolute versus relative changes in water deficit, and these two model types led to different forecasts of mortality vulnerability under future climate scenarios. Our results provide evidence for differing climatic controls of tree mortality in water- and energy-limited forests, while highlighting the need for an improved understanding of tree mortality processes.

  1. 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 (...

  2. A decision tree approach using silvics to guide planning for forest restoration

    Science.gov (United States)

    Sharon M. Hermann; John S. Kush; John C. Gilbert

    2013-01-01

    We created a decision tree based on silvics of longleaf pine (Pinus palustris) and historical descriptions to develop approaches for restoration management at Horseshoe Bend National Military Park located in central Alabama. A National Park Service goal is to promote structure and composition of a forest that likely surrounded the 1814 battlefield....

  3. A multivariate decision tree analysis of biophysical factors in tropical forest fire occurrence

    Science.gov (United States)

    Rey S. Ofren; Edward Harvey

    2000-01-01

    A multivariate decision tree model was used to quantify the relative importance of complex hierarchical relationships between biophysical variables and the occurrence of tropical forest fires. The study site is the Huai Kha Kbaeng wildlife sanctuary, a World Heritage Site in northwestern Thailand where annual fires are common and particularly destructive. Thematic...

  4. The impact of community-based forest management on timber tree ...

    African Journals Online (AJOL)

    Reduced-impact logging is used to minimise the negative effects of selective logging. However, it has been suggested that low-impact logging may create too little disturbance for the regeneration of the light-demanding timber tree species, hence compromising forest productivity. This study evaluates the impact of ...

  5. Abundance of green tree frogs and insects in artificial canopy gaps in a bottomland hardwood forest

    Science.gov (United States)

    Scott Horn; James L. Hanula; Michael D. Ulyshen; John C. Kilgo

    2005-01-01

    We found more green tree frogs (Hyla cinera) in canopy gaps than in closed canopy forest. Of the 331 gree ntree frogs observed, 88% were in canopy gaps. Likewise, higher numbers and biomasses of insects were captured in the open gap habitat. Flies were the most commonly collected insect group accounting for 54% of the total capture. These data...

  6. Developing Biomass Equations for Western Hemlock and Red Alder Trees in Western Oregon Forests

    Science.gov (United States)

    Krishna Poudel; Hailemariam Temesgen

    2016-01-01

    Biomass estimates are required for reporting carbon, assessing feedstock availability, and assessing forest fire threat. We developed diameter- and height-based biomass equations for Western hemlock (Tsuga heterophylla (Raf.) Sarg.) and red alder (Alnus rubra Bong.) trees in Western Oregon. A system of component biomass...

  7. Introduction to the invited issue on carbon allocation of trees and forests

    Science.gov (United States)

    Daniel Epron; Yann Nouvellon; Michael G. Ryan

    2012-01-01

    Carbon (C) allocation is a major issue in plant ecology, controlling the flows of C fixed in photosynthesis between respiration and biomass production, and between short- and long-lived and aboveground and belowground tissues. Incomplete knowledge of C allocation currently hinders accurate modelling of tree growth and forest ecosystem metabolism (Friedlingstein et al....

  8. Fire scars and tree vigor following prescribed fires in Missouri Ozark upland forests

    Science.gov (United States)

    Aaron P. Stevenson; Rose-Marie Muzika; Richard P. Guyette

    2008-01-01

    The goal of our project was to examine basal fire scars caused by prescribed fires and tree vigor in upland forests of the Missouri Ozarks. Fire scar data were collected in 100 plots from black oak (Quercus velutina Lam.), scarlet oak (Q. coccinea Muench.), Shumard oak (Q. shumardii Buckl.), post oak (Q...

  9. Spatial continuity of tree attributes in bottomland hardwood forests in the Southeastern United States

    Science.gov (United States)

    Luben D. Dimov; Jim L. Chambers; Brian Roy Lockhart

    2005-01-01

    Sustainable forest management and conservation require understanding of underlying basic structural and competitive relationships. To gain insight into these relationships, we analyzed spatial continuity of tree basal area (BA) and crown projection area (CPA) on twelve 0.64-ha plots in four mixed bottomland hardwood stands in Louisiana, Arkansas, and Mississippi....

  10. The pristine rain forest? Remnants of historical human impacts on current tree species composition and diversity

    NARCIS (Netherlands)

    Gemerden, Barend S. van; Olff, Han; Parren, Marc P.E.; Bongers, Frans

    2003-01-01

    Aim: Tropical rain forests are often regarded as pristine and undisturbed by humans. In Central Africa, community-wide disturbances by natural causes are rare and therefore current theory predicts that natural gap phase dynamics structure tree species composition and diversity. However, the dominant

  11. The pristine rain forest? Remnants of historical human impacts on current tree species composition and diversity

    NARCIS (Netherlands)

    Gemerden, van B.S.; Olff, H.; Parren, M.P.E.; Bongers, F.J.J.M.

    2003-01-01

    Aim Tropical rain forests are often regarded as pristine and undisturbed by humans. In Central Africa, community-wide disturbances by natural causes are rare and therefore current theory predicts that natural gap phase dynamics structure tree species composition and diversity. However, the dominant

  12. Community organization of tree species along soil gradients in a north-eastern USA forest

    NARCIS (Netherlands)

    Bigalow, S.W.; Canham, C.D.

    2002-01-01

    1 A study was carried out in oak-northern hardwood forest in NW Connecticut USA involving measurements of growth, light and soil environment of saplings of six canopy trees that are strongly associated with particular soil types as adults. The objectives were to determine patterns of growth response

  13. Height-diameter relationships of tropical Atlantic moist forest trees in southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Marcos Augusto da Silva Scaranello

    2012-02-01

    Full Text Available Site-specific height-diameter models may be used to improve biomass estimates for forest inventories where only diameter at breast height (DBH measurements are available. In this study, we fit height-diameter models for vegetation types of a tropical Atlantic forest using field measurements of height across plots along an altitudinal gradient. To fit height-diameter models, we sampled trees by DBH class and measured tree height within 13 one-hectare permanent plots established at four altitude classes. To select the best model we tested the performance of 11 height-diameter models using the Akaike Information Criterion (AIC. The Weibull and Chapman-Richards height-diameter models performed better than other models, and regional site-specific models performed better than the general model. In addition, there is a slight variation of height-diameter relationships across the altitudinal gradient and an extensive difference in the stature between the Atlantic and Amazon forests. The results showed the effect of altitude on tree height estimates and emphasize the need for altitude-specific models that produce more accurate results than a general model that encompasses all altitudes. To improve biomass estimation, the development of regional height-diameter models that estimate tree height using a subset of randomly sampled trees presents an approach to supplement surveys where only diameter has been measured.

  14. Ecological determinants of mean family age of angiosperm trees in forest communities in China

    Science.gov (United States)

    Qian, Hong; Chen, Shengbin

    2016-06-01

    Species assemblage in a local community is determined by the interplay of evolutionary and ecological processes. The Tropical Niche Conservatism hypothesis proposes mechanisms underlying patterns of biodiversity in biological communities along environmental gradients. This hypothesis predicts that, among other things, clades in areas with warm or wet environments are, on average, older than those in areas with cold or dry environments. Focusing on angiosperm trees in forests, this study tested the age-related prediction of the Tropical Niche Conservatism hypothesis. We related the mean family age of angiosperm trees in 57 local forests from across China with 23 current and paleo-environmental variables, which included all major temperature- and precipitation-related variables. Our study shows that the mean family age of angiosperm trees in local forests was positively correlated with temperature and precipitation. This finding is consistent with the age-related prediction of the Tropical Niche Conservatism hypothesis. Approximately 85% of the variance in the mean family age of angiosperm trees was explained by temperature-related variables, and 81% of the variance in the mean family age of angiosperm trees was explained by precipitation-related variables. Climatic conditions at the Last Glacial Maximum did not explain additional variation in mean family age after accounting for current environmental conditions.

  15. ESTIMATING WOOD VOLUME FOR PINUS BRUTIA TREES IN FOREST STANDS FROM QUICKBIRD-2 IMAGERY

    Directory of Open Access Journals (Sweden)

    P. Patias

    2016-06-01

    Full Text Available Knowledge of forest parameters, such as wood volume, is required for a sustainable forest management. Collecting such information in the field is laborious and even not feasible in inaccessible areas. In this study, tree wood volume is estimated utilizing remote sensing techniques, which can facilitate the extraction of relevant information. The study area is the University Forest of Taxiarchis, which is located in central Chalkidiki, Northern Greece and covers an area of 58km2. The tree species under study is the conifer evergreen species P. brutia (Calabrian pine. Three plot surfaces of 10m radius were used. VHR Quickbird-2 images are used in combination with an allometric relationship connecting the Tree Crown with the Diameter at breast height (Dbh, and a volume table developed for Greece. The overall methodology is based on individual tree crown delineation, based on (a the marker-controlled watershed segmentation approach and (b the GEographic Object-Based Image Analysis approach. The aim of the first approach is to extract separate segments each of them including a single tree and eventual lower vegetation, shadows, etc. The aim of the second approach is to detect and remove the “noisy” background. In the application of the first approach, the Blue, Green, Red, Infrared and PCA-1 bands are tested separately. In the application of the second approach, NDVI and image brightness thresholds are utilized. The achieved results are evaluated against field plot data. Their observed difference are between -5% to +10%.

  16. Effects of management on aquatic tree-hole communities in temperate forests are mediated by detritus amount and water chemistry.

    Science.gov (United States)

    Gossner, Martin M; Lade, Peggy; Rohland, Anja; Sichardt, Nora; Kahl, Tiemo; Bauhus, Jürgen; Weisser, Wolfgang W; Petermann, Jana S

    2016-01-01

    Arthropod communities in water-filled tree holes may be sensitive to impacts of forest management, for example via changes in environmental conditions such as resource input. We hypothesized that increasing forest management intensity (ForMI) negatively affects arthropod abundance and richness and shifts community composition and trophic structure of tree hole communities. We predicted that this shift is caused by reduced habitat and resource availability at the forest stand scale as well as reduced tree hole size, detritus amount and changed water chemistry at the tree holes scale. We mapped 910 water-filled tree holes in two regions in Germany and studied 199 tree hole inhabiting arthropod communities. We found that increasing ForMI indeed significantly reduced arthropod abundance and richness in water-filled tree holes. The most important indirect effects of management intensity on tree hole community structure were the reduced amounts of detritus for the tree hole inhabiting organisms and changed water chemistry at the tree hole scale, both of which seem to act as a habitat filter. Although habitat availability at the forest stand scale decreased with increasing management intensity, this unexpectedly increased local arthropod abundance in individual tree holes. However, regional species richness in tree holes significantly decreased with increasing management intensity, most likely due to decreased habitat diversity. We did not find that the management-driven increase in plant diversity at the forest stand scale affected communities of individual tree holes, for example via resource availability for adults. Our results suggest that management of temperate forests has to target a number of factors at different scales to conserve diverse arthropod communities in water-filled tree holes. © 2015 The Authors. Journal of Animal Ecology © 2015 British Ecological Society.

  17. Towards the harmonization between National Forest Inventory and Forest Condition Monitoring. Consistency of plot allocation and effect of tree selection methods on sample statistics in Italy.

    Science.gov (United States)

    Gasparini, Patrizia; Di Cosmo, Lucio; Cenni, Enrico; Pompei, Enrico; Ferretti, Marco

    2013-07-01

    In the frame of a process aiming at harmonizing National Forest Inventory (NFI) and ICP Forests Level I Forest Condition Monitoring (FCM) in Italy, we investigated (a) the long-term consistency between FCM sample points (a subsample of the first NFI, 1985, NFI_1) and recent forest area estimates (after the second NFI, 2005, NFI_2) and (b) the effect of tree selection method (tree-based or plot-based) on sample composition and defoliation statistics. The two investigations were carried out on 261 and 252 FCM sites, respectively. Results show that some individual forest categories (larch and stone pine, Norway spruce, other coniferous, beech, temperate oaks and cork oak forests) are over-represented and others (hornbeam and hophornbeam, other deciduous broadleaved and holm oak forests) are under-represented in the FCM sample. This is probably due to a change in forest cover, which has increased by 1,559,200 ha from 1985 to 2005. In case of shift from a tree-based to a plot-based selection method, 3,130 (46.7%) of the original 6,703 sample trees will be abandoned, and 1,473 new trees will be selected. The balance between exclusion of former sample trees and inclusion of new ones will be particularly unfavourable for conifers (with only 16.4% of excluded trees replaced by new ones) and less for deciduous broadleaves (with 63.5% of excluded trees replaced). The total number of tree species surveyed will not be impacted, while the number of trees per species will, and the resulting (plot-based) sample composition will have a much larger frequency of deciduous broadleaved trees. The newly selected trees have-in general-smaller diameter at breast height (DBH) and defoliation scores. Given the larger rate of turnover, the deciduous broadleaved part of the sample will be more impacted. Our results suggest that both a revision of FCM network to account for forest area change and a plot-based approach to permit statistical inference and avoid bias in the tree sample

  18. Biomass Equations for Tropical Forest Tree Species in Mozambique

    Directory of Open Access Journals (Sweden)

    Rosta Mate

    2014-03-01

    Full Text Available Chanfuta (Afzelia quanzensis Welw., Jambire (Millettia stuhlmannii Taub. and Umbila (Pterocarpus angolensis D.C. are, among others, three of the main tropical tree species producing commercial timber in Mozambique. The present study employed destructive biomass estimation methods at three localities in Mozambique (Inhaminga, Mavume, and Tome to acquire data on the mean diameter at breast height (DBH, and height of trees sampled in 21 stands each of Chanfuta and Jambire, and 15 stands of Umbila. Mean diameter at breast height (DBH (ob for Chanfuta, Jambire, and Umbila was: 33.8 ± 12.6 (range 13.5–61.1, 33.4 ± 7.4 (range 21.0–52.2, and 27.0 ± 9.5 (range 14.0–46.5 cm. The mean total values for biomass (kg of trees of Chanfuta, Jambire, and Umbila trees were 864, 1016, and 321 respectively. The mean percentages of total tree biomass as stem, branch and leaf respectively were 54, 43, and 3 for Chanfuta; 77, 22, and 1 for Jambire; and 46, 51, and 3 for Umbila. The best fit species-specific equation for estimating total above ground biomass (AGB was the power equation with only DBH considered as independent variable yielding coefficient of determination (R2 ranging from 0.89 to 0.97. At stand level, a total mean of 27.3 tons ha−1 biomass was determined of which studied species represented 94.6%. At plot level, total mean biomass for Jambire was 11.8 tons ha−1, Chanfuta and Umbila 9.9 and 4.1 tons ha−1 respectively. The developed power equation fitted total and stem biomass data well and could be used for biomass prediction of the studied species in Mozambique.

  19. Above ground biomass and tree species richness estimation with airborne lidar in tropical Ghana forests

    Science.gov (United States)

    Vaglio Laurin, Gaia; Puletti, Nicola; Chen, Qi; Corona, Piermaria; Papale, Dario; Valentini, Riccardo

    2016-10-01

    Estimates of forest aboveground biomass are fundamental for carbon monitoring and accounting; delivering information at very high spatial resolution is especially valuable for local management, conservation and selective logging purposes. In tropical areas, hosting large biomass and biodiversity resources which are often threatened by unsustainable anthropogenic pressures, frequent forest resources monitoring is needed. Lidar is a powerful tool to estimate aboveground biomass at fine resolution; however its application in tropical forests has been limited, with high variability in the accuracy of results. Lidar pulses scan the forest vertical profile, and can provide structure information which is also linked to biodiversity. In the last decade the remote sensing of biodiversity has received great attention, but few studies focused on the use of lidar for assessing tree species richness in tropical forests. This research aims at estimating aboveground biomass and tree species richness using discrete return airborne lidar in Ghana forests. We tested an advanced statistical technique, Multivariate Adaptive Regression Splines (MARS), which does not require assumptions on data distribution or on the relationships between variables, being suitable for studying ecological variables. We compared the MARS regression results with those obtained by multilinear regression and found that both algorithms were effective, but MARS provided higher accuracy either for biomass (R2 = 0.72) and species richness (R2 = 0.64). We also noted strong correlation between biodiversity and biomass field values. Even if the forest areas under analysis are limited in extent and represent peculiar ecosystems, the preliminary indications produced by our study suggest that instrument such as lidar, specifically useful for pinpointing forest structure, can also be exploited as a support for tree species richness assessment.

  20. Pinus halepensis tree-ring widths at the periphery of the eastern Mediterranean forest growth as a possible proxy for recontruction of vegetation greeness.

    Science.gov (United States)

    Ababneh, L. N.

    2015-12-01

    The IPCC report (2014) signifies the importance of understanding the dynamic and elastic relationship between global climate change and forest growth as ramifications are still uncertain despite increased experimental efforts (IPCC 2014, Frank et al.,2015). Further, understanding and modeling this relationship is over emphasized in arid to semi-arid areas such as the Middle East where limited natural resources have proven record of correlation with conflict (e.g.Kelley et al., 2015). This work reports on the response of a forest stand of Pinus halepensis (Aleppo pine) from north Jordan to variability in precipitation using instrumental and satellite derived data. The site is located in north Jordan on the transitional zones from forest to steppe of the eastern Mediterranean as classified by the European Forest Genetic Resources Programme (EUFORGEN, 2015). The aim is to model the relationship between annual earlywood, latewood and tree-ring width indices with instrumental data, reanalysis data and Normalized Difference Vegetation Index (NDVI) in the period from 1976-2012 for a possible use of tree-ring widths as vegetation greenness proxy. The highest significant correlation (pgrowth and prior spring precipitation (instrumental and reanalysis) and NDVI. Reanalysis data correlates significantly (ptree-ring widths and vegetation index that offers the potential for reconstruction of vegetation index if applied at the regional level and could be extrapolated to desert areas that lacks proxy data with annually resolved resolution such as tree-rings.

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

    Science.gov (United States)

    Covey, Kristofer

    2017-04-01

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

  2. Tree species traits cause divergence in soil acidification during four decades of postagricultural forest development

    DEFF Research Database (Denmark)

    Schrijver, An de; Frenne, Pieter de; Staelens, Jeroen

    2012-01-01

    and unequivocally drives postagricultural forests towards more acidic conditions, but the rate of soil acidification is also determined by the tree species-specific leaf litter quality and litter decomposition rates. We propose that the intrinsic differences in leaf litter quality among tree species create...... fundamentally different nutrient cycles within the ecosystem, both directly through the chemical composition of the litter and indirectly through its effects on the size and composition of earthworm communities. Poor leaf litter quality contributes to the absence of a burrowing earthworm community, which...... retards leaf litter decomposition and, consequently, results in forest-floor build-up and soil acidification. Also nutrient uptake and N2 fixation are causing soil acidification, but were found to be less important. Our results highlight the fact that tree species-specific traits significantly influence...

  3.  A global evaluation of forest interior area dynamics using tree cover data from 2000 to 2012

    Science.gov (United States)

    Kurt Riitters; James Wickham; Jennifer K. Costanza; Peter Vogt

    2016-01-01

    Context Published maps of global tree cover derived from Landsat data have indicated substantial changes in forest area from 2000 to 2012. The changes can be arranged in different patterns, with different consequences for forest fragmentation. Thus, the changes in forest area do not necessarily equate to changes in...

  4. Calcium mineralization in the forest floor and surface soil beneath different tree species in the northeastern US

    NARCIS (Netherlands)

    Dijkstra, F.A.

    2003-01-01

    Calcium (Ca) is an important element for neutralizing soil acidity in temperate forests. The immediate availability of Ca in forested acid soils is largely dependent on mineralization of organic Ca, which may differ significantly among tree species. I estimated net Ca mineralization in the forest

  5. Predicting live and dead tree basal area of bark beetle affected forests from discrete-return lidar

    Science.gov (United States)

    Benjamin C. Bright; Andrew T. Hudak; Robert McGaughey; Hans-Erik Andersen; Jose Negron

    2013-01-01

    Bark beetle outbreaks have killed large numbers of trees across North America in recent years. Lidar remote sensing can be used to effectively estimate forest biomass, but prediction of both live and dead standing biomass in beetle-affected forests using lidar alone has not been demonstrated. We developed Random Forest (RF) models predicting total, live, dead, and...

  6. Germination of important East African mountain forest trees ...

    African Journals Online (AJOL)

    Primary forest species mainly germinated under low illumination or dark conditions and showed a very short seed viability. The storage temperature did not influence viability, whereas the maturity of the seeds collected had a considerable influence on the germination success. Journal of East African Natural History Vol.

  7. Factors Influencing Elephants to Destroy Forest Trees Especially ...

    African Journals Online (AJOL)

    Elephants are terrestrial mammals which adapt to many habitats ranging from forests to deserts. At birth an elephant weighs up to 120 kg and an average of 4,000 to 6,500 kg at maturity. Elephants are herbivorous and their feeding pattern greatly impact on vegetation. This study examined factors which lead elephants to ...

  8. Tree Diametric Increment and Litterfall Production in an Eastern Amazonian Forest: the Role of Functional Groups

    Science.gov (United States)

    Camargo, P. B. D.; Ferreira, M. L.; Oliveira Junior, R. C.; Saleska, S. R.

    2014-12-01

    Tree growth is a biotic variable of great importance in understanding the dynamics of tree communities and may be used as a tool in studies of biological or climate modeling. Some climate models predict more recurrent climate anomalies in this century, which may alter the functioning of tropical forests with serious structural and demographic implications. The present study aimed to evaluate the profile of tree growth and litterfall production in an eastern Amazon forest, which has suffered recent climatic disturbances. We contrasted different functional groups based on wood density (stem with 0.55; 0.56-0.7; >0.7 g cm-3), light availability (crown illumination index; high illuminated crown - IIC1 until shaded crown - IIC5), and, size class (trees 10-22.5; 22.6-35; 35.1-55; 55,1-90; >90 cm dbh). Tree diameter increment was monthly measured from November 2011 to September 2013 by using dendrometer bands installed on 850 individuals from different families. Litterfall was collected in 64 circular traps, oven dried and weighed, separated into leaves, twigs, reproductive parts and miscellaneous. During the rainy season the sampled trees had the highest rates of tree diametric increment. When analyzing the data by functional groups, large trees had faster growth, but when grouped by wood density, trees with wood density up to 0.55 and between 0.56 and 0.7 g cm-3 had the fastest rates of growth. When grouped by crown illumination index, trees exposed to higher levels of light grew more in comparison to partially shaded trees. Maximum daily air temperature and precipitation were the most important environmental variables in determining the diametric increment profile of the trees. Litterfall production was estimated to be 7.1 Mg ha-1.year-1 and showed a strong seasonal pattern, with dry season production being higher than in the rainy season. Leaves formed the largest fraction of the litterfall, followed by twigs, reproductive parts, and finally miscellaneous. These

  9. Leaf function in tropical rain forest canopy trees : the effect of light on leaf morphology and physiology in different-sized trees

    NARCIS (Netherlands)

    Rijkers, T.

    2000-01-01

    In this thesis the effect of constant and fluctuating light availability on several leaf traits was studied for naturally growing trees of different sizes, i.e . from sapling to adult canopy tree, of five species in a tropical rain forest in French Guiana. Leaf

  10. Tree species diversity mitigates disturbance impacts on the forest carbon cycle.

    Science.gov (United States)

    Pedro, Mariana Silva; Rammer, Werner; Seidl, Rupert

    2015-03-01

    Biodiversity fosters the functioning and stability of forest ecosystems and, consequently, the provision of crucial ecosystem services that support human well-being and quality of life. In particular, it has been suggested that tree species diversity buffers ecosystems against the impacts of disturbances, a relationship known as the "insurance hypothesis". Natural disturbances have increased across Europe in recent decades and climate change is expected to amplify the frequency and severity of disturbance events. In this context, mitigating disturbance impacts and increasing the resilience of forest ecosystems is of growing importance. We have tested how tree species diversity modulates the impact of disturbance on net primary production and the total carbon stored in living biomass for a temperate forest landscape in Central Europe. Using the simulation model iLand to study the effect of different disturbance regimes on landscapes with varying levels of tree species richness, we found that increasing diversity generally reduces the disturbance impact on carbon storage and uptake, but that this effect weakens or even reverses with successional development. Our simulations indicate a clear positive relationship between diversity and resilience, with more diverse systems experiencing lower disturbance-induced variability in their trajectories of ecosystem functioning. We found that positive effects of tree species diversity are mainly driven by an increase in functional diversity and a modulation of traits related to recolonization and resource usage. The results of our study suggest that increasing tree species diversity could mitigate the effects of intensifying disturbance regimes on ecosystem functioning and improve the robustness of forest carbon storage and the role of forests in climate change mitigation.

  11. Temperature and rainfall strongly drive temporal growth variation in Asian tropical forest trees.

    Science.gov (United States)

    Vlam, Mart; Baker, Patrick J; Bunyavejchewin, Sarayudh; Zuidema, Pieter A

    2014-04-01

    Climate change effects on growth rates of tropical trees may lead to alterations in carbon cycling of carbon-rich tropical forests. However, climate sensitivity of broad-leaved lowland tropical trees is poorly understood. Dendrochronology (tree-ring analysis) provides a powerful tool to study the relationship between tropical tree growth and annual climate variability. We aimed to establish climate-growth relationships for five annual-ring forming tree species, using ring-width data from 459 canopy and understory trees from a seasonal tropical forest in western Thailand. Based on 183/459 trees, chronologies with total lengths between 29 and 62 years were produced for four out of five species. Bootstrapped correlation analysis revealed that climate-growth responses were similar among these four species. Growth was significantly negatively correlated with current-year maximum and minimum temperatures, and positively correlated with dry-season precipitation levels. Negative correlations between growth and temperature may be attributed to a positive relationship between temperature and autotrophic respiration rates. The positive relationship between growth and dry-season precipitation levels likely reflects the strong water demand during leaf flush. Mixed-effect models yielded results that were consistent across species: a negative effect of current wet-season maximum temperatures on growth, but also additive positive effects of, for example, prior dry-season maximum temperatures. Our analyses showed that annual growth variability in tropical trees is determined by a combination of both temperature and precipitation variability. With rising temperature, the predominantly negative relationship between temperature and growth may imply decreasing growth rates of tropical trees as a result of global warming.

  12. Tree diversity promotes generalist herbivore community patterns in a young subtropical forest experiment.

    Science.gov (United States)

    Zhang, Jiayong; Bruelheide, Helge; Chen, Xufei; Eichenberg, David; Kröber, Wenzel; Xu, Xuwen; Xu, Liting; Schuldt, Andreas

    2017-02-01

    Stand diversification is considered a promising management approach to increasing the multifunctionality and ecological stability of forests. However, how tree diversity affects higher trophic levels and their role in regulating forest functioning is not well explored particularly for (sub)tropical regions. We analyzed the effects of tree species richness, community composition, and functional diversity on the abundance, species richness, and beta diversity of important functional groups of herbivores and predators in a large-scale forest biodiversity experiment in south-east China. Tree species richness promoted the abundance, but not the species richness, of the dominant, generalist herbivores (especially, adult leaf chewers), probably through diet mixing effects. In contrast, tree richness did not affect the abundance of more specialized herbivores (larval leaf chewers, sap suckers) or predators (web and hunting spiders), and only increased the species richness of larval chewers. Leaf chemical diversity was unrelated to the arthropod data, and leaf morphological diversity only positively affected oligophagous herbivore and hunting spider abundance. However, richness and abundance of all arthropods showed relationships with community-weighted leaf trait means (CWM). The effects of trait diversity and CWMs probably reflect specific nutritional or habitat requirements. This is supported by the strong effects of tree species composition and CWMs on herbivore and spider beta diversity. Although specialized herbivores are generally assumed to determine herbivore effects in species-rich forests, our study suggests that generalist herbivores can be crucial for trophic interactions. Our results indicate that promoting pest control through stand diversification might require a stronger focus on identifying the best-performing tree species mixtures.

  13. Tree Circumference Dynamics in Four Forests Characterized Using Automated Dendrometer Bands.

    Science.gov (United States)

    Herrmann, Valentine; McMahon, Sean M; Detto, Matteo; Lutz, James A; Davies, Stuart J; Chang-Yang, Chia-Hao; Anderson-Teixeira, Kristina J

    2016-01-01

    Stem diameter is one of the most commonly measured attributes of trees, forming the foundation of forest censuses and monitoring. Changes in tree stem circumference include both irreversible woody stem growth and reversible circumference changes related to water status, yet these fine-scale dynamics are rarely leveraged to understand forest ecophysiology and typically ignored in plot- or stand-scale estimates of tree growth and forest productivity. Here, we deployed automated dendrometer bands on 12-40 trees at four different forested sites-two temperate broadleaf deciduous, one temperate conifer, and one tropical broadleaf semi-deciduous-to understand how tree circumference varies on time scales of hours to months, how these dynamics relate to environmental conditions, and whether the structure of these variations might introduce substantive error into estimates of woody growth. Diurnal stem circumference dynamics measured over the bark commonly-but not consistently-exhibited daytime shrinkage attributable to transpiration-driven changes in stem water storage. The amplitude of this shrinkage was significantly correlated with climatic variables (daily temperature range, vapor pressure deficit, and radiation), sap flow and evapotranspiration. Diurnal variations were typically <0.5 mm circumference in amplitude and unlikely to be of concern to most studies of tree growth. Over time scales of multiple days, the bands captured circumference increases in response to rain events, likely driven by combinations of increased stem water storage and bark hydration. Particularly at the tropical site, these rain responses could be quite substantial, ranging up to 1.5 mm circumference expansion within 48 hours following a rain event. We conclude that over-bark measurements of stem circumference change sometimes correlate with but have limited potential for directly estimating daily transpiration, but that they can be valuable on time scales of days to weeks for characterizing

  14. Tree Circumference Dynamics in Four Forests Characterized Using Automated Dendrometer Bands.

    Directory of Open Access Journals (Sweden)

    Valentine Herrmann

    Full Text Available Stem diameter is one of the most commonly measured attributes of trees, forming the foundation of forest censuses and monitoring. Changes in tree stem circumference include both irreversible woody stem growth and reversible circumference changes related to water status, yet these fine-scale dynamics are rarely leveraged to understand forest ecophysiology and typically ignored in plot- or stand-scale estimates of tree growth and forest productivity. Here, we deployed automated dendrometer bands on 12-40 trees at four different forested sites-two temperate broadleaf deciduous, one temperate conifer, and one tropical broadleaf semi-deciduous-to understand how tree circumference varies on time scales of hours to months, how these dynamics relate to environmental conditions, and whether the structure of these variations might introduce substantive error into estimates of woody growth. Diurnal stem circumference dynamics measured over the bark commonly-but not consistently-exhibited daytime shrinkage attributable to transpiration-driven changes in stem water storage. The amplitude of this shrinkage was significantly correlated with climatic variables (daily temperature range, vapor pressure deficit, and radiation, sap flow and evapotranspiration. Diurnal variations were typically <0.5 mm circumference in amplitude and unlikely to be of concern to most studies of tree growth. Over time scales of multiple days, the bands captured circumference increases in response to rain events, likely driven by combinations of increased stem water storage and bark hydration. Particularly at the tropical site, these rain responses could be quite substantial, ranging up to 1.5 mm circumference expansion within 48 hours following a rain event. We conclude that over-bark measurements of stem circumference change sometimes correlate with but have limited potential for directly estimating daily transpiration, but that they can be valuable on time scales of days to weeks

  15. Multiple browsers structure tree recruitment in logged temperate forests

    Science.gov (United States)

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

    2016-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Edward K Faison

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

  17. Predicting spatial variations of tree species richness in tropical forests from high-resolution remote sensing.

    Science.gov (United States)

    Fricker, Geoffrey A; Wolf, Jeffrey A; Saatchi, Sassan S; Gillespie, Thomas W

    2015-10-01

    There is an increasing interest in identifying theories, empirical data sets, and remote-sensing metrics that can quantify tropical forest alpha diversity at a landscape scale. Quantifying patterns of tree species richness in the field is time consuming, especially in regions with over 100 tree species/ha. We examine species richness in a 50-ha plot in Barro Colorado Island in Panama and test if biophysical measurements of canopy reflectance from high-resolution satellite imagery and detailed vertical forest structure and topography from light detection and ranging (lidar) are associated with species richness across four tree size classes (>1, 1-10, >10, and >20 cm dbh) and three spatial scales (1, 0.25, and 0.04 ha). We use the 2010 tree inventory, including 204,757 individuals belonging to 301 species of freestanding woody plants or 166 ± 1.5 species/ha (mean ± SE), to compare with remote-sensing data. All remote-sensing metrics became less correlated with species richness as spatial resolution decreased from 1.0 ha to 0.04 ha and tree size increased from 1 cm to 20 cm dbh. When all stems with dbh > 1 cm in 1-ha plots were compared to remote-sensing metrics, standard deviation in canopy reflectance explained 13% of the variance in species richness. The standard deviations of canopy height and the topographic wetness index (TWI) derived from lidar were the best metrics to explain the spatial variance in species richness (15% and 24%, respectively). Using multiple regression models, we made predictions of species richness across Barro Colorado Island (BCI) at the 1-ha spatial scale for different tree size classes. We predicted variation in tree species richness among all plants (adjusted r² = 0.35) and trees with dbh > 10 cm (adjusted r² = 0.25). However, the best model results were for understory trees and shrubs (dbh 1-10 cm) (adjusted r² = 0.52) that comprise the majority of species richness in tropical forests. Our results indicate that high

  18. Linking individual-tree and whole-stand models for forest growth and yield prediction

    Directory of Open Access Journals (Sweden)

    Quang V Cao

    2014-10-01

    Full Text Available Background Different types of growth and yield models provide essential information for making informed decisions on how to manage forests. Whole-stand models often provide well-behaved outputs at the stand level, but lack information on stand structures. Detailed information from individual-tree models and size-class models typically suffers from accumulation of errors. The disaggregation method, in assuming that predictions from a whole-stand model are reliable, partitions these outputs to individual trees. On the other hand, the combination method seeks to improve stand-level predictions from both whole-stand and individual-tree models by combining them. Methods Data from 100 plots randomly selected from the Southwide Seed Source Study of loblolly pine (Pinus taeda L. were used to evaluate the unadjusted individual-tree model against the disaggregation and combination methods. Results Compared to the whole-stand model, the combination method did not show improvements in predicting stand attributes in this study. The combination method also did not perform as well as the disaggregation method in tree-level predictions. The disaggregation method provided the best predictions of tree- and stand-level survival and growth. Conclusions The disaggregation approach provides a link between individual-tree models and whole-stand models, and should be considered as a better alternative to the unadjusted tree model.

  19. National forest change monitoring system in South Korea: an analysis of forest tree species distribution shifts

    Science.gov (United States)

    Eun-Sook Kim; Cheol-Min Kim; Jisun Lee; Jong-Su. Yim

    2015-01-01

    Since 1971, South Korea has implemented national forest inventory (NFI) in pursuance of understanding current state and change trend of national forest resources. NFI1 (1971~1975), NFI2 (1978~1981), NFI3 (1986~1992) and NFI4 (1996~2005) were implemented in order to produce national forest resources statistics. However, since the early 1990s, international conventions...

  20. 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

  1. Extent of localized tree mortality influences soil biogeochemical response in a beetle-infested coniferous forest

    Science.gov (United States)

    Brouillard, Brent; Mikkelson, Kristin; Bokman, Chelsea; Berryman, Erin Michele; Sharp, Jonathan

    2017-01-01

    Recent increases in the magnitude and occurrence of insect-induced tree mortality are disruptingevergreen forests globally. To resolve potentially conflicting ecosystem responses, we investigatedwhether surrounding trees exert compensatory effects on biogeochemical signatures following beetleinfestation. To this end, plots were surveyed within a Colorado Rocky Mountain watershed that expe-rienced beetle infestation almost a decade prior and contained a range of surrounding tree mortality(from 9 to 91% of standing trees). Near-surface soil horizons under plot-centered live (green) and beetle-killed (grey) lodgepole pines were sampled over two consecutive summers with variable moistureconditions. Results revealed that soil respiration was 18e28% lower beneath beetle-infested trees andcorrelated to elevated dissolved organic carbon aromaticity. While certain edaphic parameters includingpH and water content were elevated below grey compared to green trees regardless of the mortalityextent within plots, other biogeochemical responses required a higher severity of surrounding mortalityto overcome compensatory effects of neighboring live trees. For instance, C:N ratios under grey treesdeclined with increased severity of surrounding tree mortality, and the proportion of ammonium dis-played a threshold effect with pronounced increases after surrounding tree mortality exceeded ~40%.Overall, the biogeochemical response to tree death was most prominent in the mineral soil horizonwhere tree mortality had the largest affect on carbon recalcitrance and the enrichment of nitrogenspecies. These results can aid in determining when and where nutrient cycles and biogeochemicalfeedbacks to the atmosphere and hydrosphere will be observed in association with this type of ecological disturbance.

  2. Abundance and Size Distribution of Cavity Trees in Second-Growth and Old-Growth Central Hardwood Forests

    Science.gov (United States)

    Zhaofei Fan; Stephen R. Shifley; Martin A. Spetich; Frank R. Thompson III; David R. Larsen

    2005-01-01

    In central hardwood forests, mean cavity-tree abundance increases with increasing standsize class (seedling/sapling, pole, sawtimber, old-growth). However, within a size class, the number of cavity trees is highly variable among 0.1-ha inventory plots. Plots in young stands are most likely to have no cavity trees, but some plots may have more than 50 cavity trees/ha....

  3. Tropical forest restoration: tree islands as recruitment foci in degraded lands of Honduras.

    Science.gov (United States)

    Zahawi, R A; Augspurger, C K

    2006-04-01

    Tropical forest recovery in pastures is slowed by a number of biotic and abiotic factors, including a lack of adequate seed dispersal and harsh microclimatic extremes. Accordingly, methods to accelerate forest recovery must address multiple impediments. Here, we evaluated the ability of "tree islands" to serve as "recruitment foci" in a two-year study at three sites in northern Honduras. Islands of three sizes (64, 16, and 4 m2) and at two distances to secondary forest (20 and 50 m) were created by planting 2 m tall vegetative stakes of two native species: Gliricidia sepium (Fabaceae) and Bursera simaruba (Burseraceae), each in monoculture. Open-pasture "islands" of equal sizes served as controls. Tree islands reduced temperature and light (PAR) extremes as compared to open pasture, creating a microenvironment more favorable to seedling establishment. Seed-dispersing birds (quantified at one site only) showed an overwhelming preference for islands; 160 visits were recorded to islands compared with one visit to open pasture. Additionally, frugivores visited large islands more often, and for longer time periods, than small islands, thereby increasing the likelihood of a dispersal event there. In total, 144 140 seeds belonging to 186 species were collected in islands; more than 80% were grasses. Tree islands increased zoochorous tree seed rain; seed density and species richness were greater in tree islands than in open pasture, and large islands had greater seed density than smaller islands (Gliricidia only), suggesting that they are more effective for restoration. Distance to forest did not affect seed rain. A total of 543 seedlings and 41 species established in islands; > 85% were zoochorous. Seedling density did not differ among treatments (mean 0.2 seedlings/m2 for islands vs. 0.1 seedlings/m2 for pasture), although an increasing trend in tree islands over the course of two years suggests that seedling recruitment is accelerated there. Lastly, similar seedling

  4. Jack-of-all-trades effects drive biodiversity–ecosystem multifunctionality relationships in European forests

    Science.gov (United States)

    van der Plas, Fons; Manning, Peter; Allan, Eric; Scherer-Lorenzen, Michael; Verheyen, Kris; Wirth, Christian; Zavala, Miguel A.; Hector, Andy; Ampoorter, Evy; Baeten, Lander; Barbaro, Luc; Bauhus, Jürgen; Benavides, Raquel; Benneter, Adam; Berthold, Felix; Bonal, Damien; Bouriaud, Olivier; Bruelheide, Helge; Bussotti, Filippo; Carnol, Monique; Castagneyrol, Bastien; Charbonnier, Yohan; Coomes, David; Coppi, Andrea; Bastias, Cristina C.; Muhie Dawud, Seid; De Wandeler, Hans; Domisch, Timo; Finér, Leena; Gessler, Arthur; Granier, André; Grossiord, Charlotte; Guyot, Virginie; Hättenschwiler, Stephan; Jactel, Hervé; Jaroszewicz, Bogdan; Joly, François-Xavier; Jucker, Tommaso; Koricheva, Julia; Milligan, Harriet; Müller, Sandra; Muys, Bart; Nguyen, Diem; Pollastrini, Martina; Raulund-Rasmussen, Karsten; Selvi, Federico; Stenlid, Jan; Valladares, Fernando; Vesterdal, Lars; Zielínski, Dawid; Fischer, Markus

    2016-01-01

    There is considerable evidence that biodiversity promotes multiple ecosystem functions (multifunctionality), thus ensuring the delivery of ecosystem services important for human well-being. However, the mechanisms underlying this relationship are poorly understood, especially in natural ecosystems. We develop a novel approach to partition biodiversity effects on multifunctionality into three mechanisms and apply this to European forest data. We show that throughout Europe, tree diversity is positively related with multifunctionality when moderate levels of functioning are required, but negatively when very high function levels are desired. For two well-known mechanisms, ‘complementarity' and ‘selection', we detect only minor effects on multifunctionality. Instead a third, so far overlooked mechanism, the ‘jack-of-all-trades' effect, caused by the averaging of individual species effects on function, drives observed patterns. Simulations demonstrate that jack-of-all-trades effects occur whenever species effects on different functions are not perfectly correlated, meaning they may contribute to diversity–multifunctionality relationships in many of the world's ecosystems. PMID:27010076

  5. Water and forests in the Mediterranean hot climate zone: a review based on a hydraulic interpretation of tree functioning

    Energy Technology Data Exchange (ETDEWEB)

    Soares David, T.; Assunção Pinto, C.; Nadezhdina, N.; Soares David, J.

    2016-07-01

    Aim of the study: Water scarcity is the main limitation to forest growth and tree survival in the Mediterranean hot climate zone. This paper reviews literature on the relations between water and forests in the region, and their implications on forest and water resources management. The analysis is based on a hydraulic interpretation of tree functioning. Area of the study: The review covers research carried out in the Mediterranean hot climate zone, put into perspective of wider/global research on the subject. The scales of analysis range from the tree to catchment levels. Material and Methods: For literature review we used Sc opus, Web of Science and Go ogle Scholar as bibliographic databases. Data from two Quercus suber sites in Portugal were used for illustrative purposes. Main results: We identify knowledge gaps and discuss options to better adapt forest management to climate change under a tree water use/availability perspective. Forest management is also discussed within the wider context of catchment water balance: water is a constraint for biomass production, but also for other human activities such as urban supply, industry and irrigated agriculture. Research highlights: Given the scarce and variable (in space and in time) water availability in the region, further research is needed on: mapping the spatial heterogeneity of water availability to trees; adjustment of tree density to local conditions; silviculture practices that do not damage soil properties or roots; irrigation of forest plantations in some specific areas; tree breeding. Also, a closer cooperation between forest and water managers is needed. (Author)

  6. Alterations in the nitrogen dynamics of European beech trees infested by the woolly beech aphid

    Science.gov (United States)

    Levia, D. F.; Michalzik, B.

    2012-12-01

    Insects are a major stressor in wooded ecosystems, triggering profound changes in the hydrology, biogeochemistry, and net primary productivity of infested forests. The influence of woolly beech aphids (Phyllaphis fagi L.) on nitrogen cycling via throughfall, stemflow, and litter leachates is not well understood. Employing a combination of field sampling, X-ray photoelectron spectroscopy, and scanning electron microscopy, we examined and compared the alterations and partitioning of nitrogen (particulate, dissolved, organic, inorganic) between control (uninfested) and infested trees. Preliminary results suggest that the amount of nitrogen routed to the soil is much lower in throughfall and stemflow of infested trees than control trees. Preliminary X-ray photoelectron spectroscopy and scanning electron microscopy measurements on the abaxial surface of sample leaves have demonstrated that the surface microbiology and nitrogen chemistry of control, lightly infested, and heavily infested leaves are notably different. These observations suggest that the aphids alter the phyllosphere ecology to such an extent that they trigger nitrogen uptake by microbes on the leaf surface in the presence of easily available carbon from aphid excretions (i.e., honeydew). A better understanding of nitrogen cycling in stressed forests would advance theories of nitrogen cycling.

  7. Avian species richness in relation to intensive forest management practices in early seral tree plantations.

    Directory of Open Access Journals (Sweden)

    Jay E Jones

    Full Text Available BACKGROUND: Managers of landscapes dedicated to forest commodity production require information about how practices influence biological diversity. Individual species and communities may be threatened if management practices truncate or simplify forest age classes that are essential for reproduction and survival. For instance, the degradation and loss of complex diverse forest in young age classes have been associated with declines in forest-associated Neotropical migrant bird populations in the Pacific Northwest, USA. These declines may be exacerbated by intensive forest management practices that reduce hardwood and broadleaf shrub cover in order to promote growth of economically valuable tree species in plantations. METHODOLOGY AND PRINCIPAL FINDINGS: We used a Bayesian hierarchical model to evaluate relationships between avian species richness and vegetation variables that reflect stand management intensity (primarily via herbicide application on 212 tree plantations in the Coast Range, Oregon, USA. Specifically, we estimated the influence of broadleaf hardwood vegetation cover, which is reduced through herbicide applications, on bird species richness and individual species occupancy. Our model accounted for imperfect detection. We used average predictive comparisons to quantify the degree of association between vegetation variables and species richness. Both conifer and hardwood cover were positively associated with total species richness, suggesting that these components of forest stand composition may be important predictors of alpha diversity. Estimates of species richness were 35-80% lower when imperfect detection was ignored (depending on covariate values, a result that has critical implications for previous efforts that have examined relationships between forest composition and species richness. CONCLUSION AND SIGNIFICANCE: Our results revealed that individual and community responses were positively associated with both conifer and

  8. Warming and provenance limit tree recruitment across and beyond the elevation range of subalpine forest.

    Science.gov (United States)

    Kueppers, Lara M; Conlisk, Erin; Castanha, Cristina; Moyes, Andrew B; Germino, Matthew J; de Valpine, Perry; Torn, Margaret S; Mitton, Jeffry B

    2017-06-01

    Climate niche models project that subalpine forest ranges will extend upslope with climate warming. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, but raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased season-average soil moisture similarly across sites. Contrary to expectations, warming reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. Warming reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free season alleviated some negative effects of warming, indicating that warming exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to warming across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with warming, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The lower

  9. Warming and provenance limit tree recruitment across and beyond the elevation range of subalpine forest

    Science.gov (United States)

    Kueppers, Lara M.; Conlisk, Erin; Castanha, Cristina; Moyes, Andrew B.; Germino, Matthew; de Valpine, Perry; Torn, Margaret S.; Mitton, Jeffry B.

    2017-01-01

    Climate niche models project that subalpine forest ranges will extend upslope with climate warming. These projections assume that the climate suitable for adult trees will be adequate for forest regeneration, ignoring climate requirements for seedling recruitment, a potential demographic bottleneck. Moreover, local genetic adaptation is expected to facilitate range expansion, with tree populations at the upper forest edge providing the seed best adapted to the alpine. Here, we test these expectations using a novel combination of common gardens, seeded with two widely distributed subalpine conifers, and climate manipulations replicated at three elevations. Infrared heaters raised temperatures in heated plots, but raised temperatures more in the forest than at or above treeline because strong winds at high elevation reduced heating efficiency. Watering increased season-average soil moisture similarly across sites. Contrary to expectations, warming reduced Engelmann spruce recruitment at and above treeline, as well as in the forest. Warming reduced limber pine first-year recruitment in the forest, but had no net effect on fourth-year recruitment at any site. Watering during the snow-free season alleviated some negative effects of warming, indicating that warming exacerbated water limitations. Contrary to expectations of local adaptation, low-elevation seeds of both species initially recruited more strongly than high-elevation seeds across the elevation gradient, although the low-provenance advantage diminished by the fourth year for Engelmann spruce, likely due to small sample sizes. High- and low-elevation provenances responded similarly to warming across sites for Engelmann spruce, but differently for limber pine. In the context of increasing tree mortality, lower recruitment at all elevations with warming, combined with lower quality, high-provenance seed being most available for colonizing the alpine, portends range contraction for Engelmann spruce. The lower

  10. The pine-oak rusts: How forest tree species connect

    Science.gov (United States)

    D. R. Vogler

    2008-01-01

    The pine-oak rust fungi, which live out their lives as pathogens on pines and oaks, have multiple spore states and complex life cycles. Because they can be severe pathogens of pines, much of what we know about them depends on how damaging they are to management of pine forests for timber, recreation, and ecosystem values. Widely distributed in North America, they are...

  11. Effects of Warming on Tree Species’ Recruitment in Deciduous Forests of the Eastern United States

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry M. [Marine Biological Lab., Woods Hole, MA (United States); Clark, James S. [Duke Univ., Durham, NC (United States); Mohan, Jacqueline [Univ. of Georgia, Athens, GA (United States)

    2015-03-25

    Climate change is restructuring forests of the United States, although the details of this restructuring are currently uncertain. Rising temperatures of 2 to 8oC and associated changes in soil moisture will shift the competitive balance between species that compete for light and water, and so change their abilities to produce seed, germinate, grow, and survive. We have used large-scale experiments to determine the effects of warming on the most sensitive stage of species distributions, i.e., recruitment, in mixed deciduous forests in southern New England and in the Piedmont region of North Carolina. Two questions organized our research: (1) Might temperate tree species near the “warm” end of their range in the eastern United States decline in abundance during the coming century due to projected warming? and (2) Might trees near the “cool” end of their range in the eastern United States increase in abundance, or extend their range, during the coming 100 years because of projected warming? To explore these questions, we exposed seedlings to air and soil warming experiments in two eastern deciduous forest sites; one at the Harvard Forest (HF) in central Massachusetts, and the other at the Duke Forest (DF) in the Piedmont region of North Carolina. We focused on tree species common to both Harvard and Duke Forests (such as red, black, and white oaks), those near northern range limits (black oak, flowing dogwood, tulip poplar), and those near southern range limits (yellow birch, sugar maple, Virginia pine). At each site, we planted seeds and seedlings in common gardens established in temperature-controlled, open-top chambers. The experimental design was replicated and fully factorial and involved three temperature regimes (ambient, +3oC and +5oC) and two light regimes (closed forest canopy (low light) and gap conditions (high light)). Measured variables included Winter/Spring responses to temperature and mid-Summer responses to low soil moisture. This research

  12. RELATIONSHIPS BETWEEN TOTAL TREE HEIGHT AND DIAMETER AT BREAST HEIGHT FOR TROPICAL PEAT SWAMP FOREST TREE SPECIES IN ROKAN HILIR DISTRICT, RIAU PROVINCE

    Directory of Open Access Journals (Sweden)

    Nunung Puji Nugroho

    2016-06-01

    Full Text Available Reliable information on total tree height (H is fundamental in forest resource management and forest ecological studies, including in forest biomass assessment. Adding an H variable can improve the performance of the biomass allometric equations by reducing the average deviation significantly. However, measuring H is relatively complex, less accurate, time consuming, and expensive. Thus, H is only measured for sampled trees within the plots, whilst diameter at breast height (DBH is commonly measured for each tree during the forest inventory. The missing H information is usually estimated based on a stand-specific allometric relationship between H and DBH (H-D model constructed from sampled trees. Despite extensive studies on H-D model for boreal forests and for single-species/plantation forests, few studies have focused on tropical forests. Furthermore, relationships for peat swamp forest tree species, and especially those in Indonesia, have not been widely published. Thus, the objective of this study was to develop site-specific H-D models for tropical peat swamp forests using linearized and non-linear regression functions. The results indicated that the non-linear models outperformed the linearized models based on the statistical parameters and the biological criteria. The modified logistic function (Model 7 is recommended for estimating H in the study area as it has comparable model performances to the exponential function (Model 6 and passed the point diameter-height of (0, 1.3. However, all five non-linear models performed equally well and the differences between them were trivial. Further improvements are needed to improve the accuracy, the predictive ability and the geographical applicability of the models by grouping the species, adding stand variables and (or using advanced techniques of mixed-effect modelling. In addition, model validation should be carried out prior to their application by collecting a new dataset from the forest

  13. A Global Perspective on Warmer Droughts as a Key Driver of Forest Disturbances and Tree Mortality (Invited)

    Science.gov (United States)

    Allen, C. D.

    2013-12-01

    Recent global warming, in concert with episodic droughts, is causing elevated levels of both chronic and acute forest water stress across large regions. Such increases in water stress affect forest dynamics in multiple ways, including by amplifying the incidence and severity of many significant forest disturbances, particularly drought-induced tree mortality, wildfire, and outbreaks of damaging insects and diseases. Emerging global-scale patterns of drought-related forest die-off are presented, including a newly updated map overview of documented drought- and heat-induced tree mortality events from around the world, demonstrating the vulnerability of all major forest types to forest drought stress, even in typically wet environments. Comparative patterns of drought stress and associated forest disturbances are reviewed for several regions (southwestern Australia, Inner Asia, western North America, Mediterranean Basin), including interactions among climate and various disturbance processes. From the Southwest USA, research is presented that derives a tree-ring-based Forest Drought Stress Index (FDSI) for the most regionally-widespread conifer species (Pinus edulis, Pinus ponderosa, and Pseudotsuga menziesii), demonstrating recent escalation of FDSI to extreme levels relative to the past 1000 years, due to both drought and especially warming. This new work further highlights strong correlations between drought stress and amplified forest disturbances (fire, bark beetle outbreaks), and projects that by CE 2050 anticipated regional warming will cause mean FDSI values to reach historically unprecedented levels that may exceed thresholds for the survival of current tree species in large portions of their current range in the Southwest. Similar patterns of recent climate-amplified forest disturbance risk are apparent from a variety of relatively dry regions across this planet, and given climate projections for substantially warmer temperatures and greater drought stress

  14. Spatial patterns of soil pathogens in declining Mediterranean forests: implications for tree species regeneration.

    Science.gov (United States)

    Gómez-Aparicio, Lorena; Ibáñez, Beatriz; Serrano, María S; De Vita, Paolo; Avila, José M; Pérez-Ramos, Ignacio M; García, Luis V; Esperanza Sánchez, M; Marañón, Teodoro

    2012-06-01

    Soil-borne pathogens are a key component of the belowground community because of the significance of their ecological and socio-economic impacts. However, very little is known about the complexity of their distribution patterns in natural systems. Here, we explored the patterns, causes and ecological consequences of spatial variability in pathogen abundance in Mediterranean forests affected by oak decline. We used spatially explicit neighborhood models to predict the abundance of soil-borne pathogen species (Phytophthora cinnamomi, Pythium spiculum and Pythium spp.) as a function of local abiotic conditions (soil texture) and the characteristics of the tree and shrub neighborhoods (species composition, size and health status). The implications of pathogen abundance for tree seedling performance were explored by conducting a sowing experiment in the same locations in which pathogen abundance was quantified. Pathogen abundance in the forest soil was not randomly distributed, but exhibited spatially predictable patterns influenced by both abiotic and, particularly, biotic factors (tree and shrub species). Pathogen abundance reduced seedling emergence and survival, but not in all sites or tree species. Our findings suggest that heterogeneous spatial patterns of pathogen abundance at fine spatial scale can be important for the dynamics and restoration of declining Mediterranean forests. © 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.

  15. Effect of Tree Species and Mycorrhizal Colonization on the Archaeal Population of Boreal Forest Rhizospheres▿

    Science.gov (United States)

    Bomberg, Malin; Timonen, Sari

    2009-01-01

    Group 1.1c Crenarchaeota are the predominating archaeal group in acidic boreal forest soils. In this study, we show that the detection frequency of 1.1c crenarchaeotal 16S rRNA genes in the rhizospheres of the boreal forest trees increased following colonization by the ectomycorrhizal fungus Paxillus involutus. This effect was very clear in the fine roots of Pinus sylvestris, Picea abies, and Betula pendula, the most common forest trees in Finland. The nonmycorrhizal fine roots had a clearly different composition of archaeal 16S rRNA genes in comparison to the mycorrhizal fine roots. In the phylogenetic analysis, the 1.1c crenarchaeotal 16S rRNA gene sequences obtained from the fine roots formed a well-defined cluster separate from the mycorrhizal ones. Alnus glutinosa differed from the other trees by having high diversity and detection levels of Crenarchaeota both on fine roots and on mycorrhizas as well as by harboring a distinct archaeal flora. The similarity of the archaeal populations in rhizospheres of the different tree species was increased upon colonization by the ectomycorrhizal fungus. A minority of the sequences obtained from the mycorrhizas belonged to Euryarchaeota (order Halobacteriales). PMID:18978075

  16. Estimation of Trees Outside Forests using IRS High Resolution data by Object Based Image Analysis

    Science.gov (United States)

    Pujar, G. S.; Reddy, P. M.; Reddy, C. S.; Jha, C. S.; Dadhwal, V. K.

    2014-11-01

    Assessment of Trees outside forests (TOF) is widely being recognized as a pivotal theme, in sustainable natural resource management, due to their role in offering variety of goods, such as timber, fruits and fodder as well as services like water, carbon, biodiversity. Forest Conservation efforts involving reduction of deforestation and degradation may have to increasingly rely on alternatives provided by TOF in catering to economic demands in forest edges. Spatial information systems involving imaging, analysis and monitoring to achieve objectives under protocols like REDD+, require incorporation of information content from areas under forest as well as trees outside forests, to aid holistic decisions. In this perspective, automation in retrieving information on area under trees, growing outside forests, using high resolution imaging is essential so that measuring and verification of extant carbon pools, are strengthened. Retrieval of this tree cover is demonstrated herewith, using object based image analysis in a forest edge of dry deciduous forests of Eastern Ghats, in Khammam district of Telangana state of India. IRS high resolution panchromatic 2.5 m data (Cartosat-1 Orthorectified) used in tandem with 5.8 m multispectral LISS IV data, discerns tree crowns and clusters at a detailed scale and hence semi-automated approach is attempted to classify TOF from a pair of image from relatively crop and cloud free season. Object based image analysis(OBIA) approach as implemented in commercial suite of e-Cognition (Ver 8.9) consists of segmentation at user defined scale followed by application of wide range of spectral, textural and object geometry based parameters for classification. Software offers innovative blend of raster and vector features that can be juxtaposed flexibly, across scales horizontally or vertically. Segmentation was carried out at multiple scales to discern first the major land covers, such as forest, water, agriculture followed by that at a finer

  17. Vertical stratification of forest canopy for segmentation of understory trees within small-footprint airborne LiDAR point clouds

    Science.gov (United States)

    Hamraz, Hamid; Contreras, Marco A.; Zhang, Jun

    2017-08-01

    Airborne LiDAR point cloud representing a forest contains 3D data, from which vertical stand structure even of understory layers can be derived. This paper presents a tree segmentation approach for multi-story stands that stratifies the point cloud to canopy layers and segments individual tree crowns within each layer using a digital surface model based tree segmentation method. The novelty of the approach is the stratification procedure that separates the point cloud to an overstory and multiple understory tree canopy layers by analyzing vertical distributions of LiDAR points within overlapping locales. The procedure does not make a priori assumptions about the shape and size of the tree crowns and can, independent of the tree segmentation method, be utilized to vertically stratify tree crowns of forest canopies. We applied the proposed approach to the University of Kentucky Robinson Forest - a natural deciduous forest with complex and highly variable terrain and vegetation structure. The segmentation results showed that using the stratification procedure strongly improved detecting understory trees (from 46% to 68%) at the cost of introducing a fair number of over-segmented understory trees (increased from 1% to 16%), while barely affecting the overall segmentation quality of overstory trees. Results of vertical stratification of the canopy showed that the point density of understory canopy layers were suboptimal for performing a reasonable tree segmentation, suggesting that acquiring denser LiDAR point clouds would allow more improvements in segmenting understory trees. As shown by inspecting correlations of the results with forest structure, the segmentation approach is applicable to a variety of forest types.

  18. Tree species identity and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    Science.gov (United States)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2015-06-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale runoff plots was conducted to investigate the influence of tree species richness and identity as well as tree functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 t ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion, but higher tree species richness did not mitigate soil losses in young forest stands. Thus, different tree morphologies have to be considered, when assessing erosion under forest. High crown cover and leaf area index reduced soil losses in initial forest ecosystems, whereas rising tree height increased them. Even if a leaf litter cover was not present, remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on soil loss. Long-term monitoring of soil erosion under closing tree canopies is necessary and a wide range of functional tree traits should be taken into consideration in future research.

  19. Tree species and functional traits but not species richness affect interrill erosion processes in young subtropical forests

    Science.gov (United States)

    Seitz, S.; Goebes, P.; Song, Z.; Bruelheide, H.; Härdtle, W.; Kühn, P.; Li, Y.; Scholten, T.

    2016-01-01

    Soil erosion is seriously threatening ecosystem functioning in many parts of the world. In this context, it is assumed that tree species richness and functional diversity of tree communities can play a critical role in improving ecosystem services such as erosion control. An experiment with 170 micro-scale run-off plots was conducted to investigate the influence of tree species and tree species richness as well as functional traits on interrill erosion in a young forest ecosystem. An interrill erosion rate of 47.5 Mg ha-1 a-1 was calculated. This study provided evidence that different tree species affect interrill erosion differently, while tree species richness did not affect interrill erosion in young forest stands. Thus, different tree morphologies have to be considered, when assessing soil erosion under forest. High crown cover and leaf area index reduced interrill erosion in initial forest ecosystems, whereas rising tree height increased it. Even if a leaf litter cover was not present, the remaining soil surface cover by stones and biological soil crusts was the most important driver for soil erosion control. Furthermore, soil organic matter had a decreasing influence on interrill erosion. Long-term monitoring of soil erosion under closing tree canopies is necessary, and a wide range of functional tree traits should be considered in future research.

  20. Seeing the Forest through the Trees: Considering Roost-Site Selection at Multiple Spatial Scales.

    Science.gov (United States)

    Jachowski, David S; Rota, Christopher T; Dobony, Christopher A; Ford, W Mark; Edwards, John W

    2016-01-01

    Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats (Myotis sodalis) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007-2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm (Ulmus americana) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural components

  1. Seeing the forest through the trees: Considering roost-site selection at multiple spatial scales

    Science.gov (United States)

    Jachowski, David S.; Rota, Christopher T.; Dobony, Christopher A.; Ford, W. Mark; Edwards, John W.

    2016-01-01

    Conservation of bat species is one of the most daunting wildlife conservation challenges in North America, requiring detailed knowledge about their ecology to guide conservation efforts. Outside of the hibernating season, bats in temperate forest environments spend their diurnal time in day-roosts. In addition to simple shelter, summer roost availability is as critical as maternity sites and maintaining social group contact. To date, a major focus of bat conservation has concentrated on conserving individual roost sites, with comparatively less focus on the role that broader habitat conditions contribute towards roost-site selection. We evaluated roost-site selection by a northern population of federally-endangered Indiana bats (Myotis sodalis) at Fort Drum Military Installation in New York, USA at three different spatial scales: landscape, forest stand, and individual tree level. During 2007–2011, we radiotracked 33 Indiana bats (10 males, 23 females) and located 348 roosting events in 116 unique roost trees. At the landscape scale, bat roost-site selection was positively associated with northern mixed forest, increased slope, and greater distance from human development. At the stand scale, we observed subtle differences in roost site selection based on sex and season, but roost selection was generally positively associated with larger stands with a higher basal area, larger tree diameter, and a greater sugar maple (Acer saccharum) component. We observed no distinct trends of roosts being near high-quality foraging areas of water and forest edges. At the tree scale, roosts were typically in American elm (Ulmus americana) or sugar maple of large diameter (>30 cm) of moderate decay with loose bark. Collectively, our results highlight the importance of considering day roost needs simultaneously across multiple spatial scales. Size and decay class of individual roosts are key ecological attributes for the Indiana bat, however, larger-scale stand structural

  2. Forest biomass variation in Southernmost Brazil: the impact of Araucaria trees.

    Science.gov (United States)

    Rosenfield, Milena Fermina; Souza, Alexandre F

    2014-03-01

    A variety of environmental and biotic factors determine vegetation growth and affect plant biomass accumulation. From temperature to species composition, aboveground biomass storage in forest ecosystems is influenced by a number of variables and usually presents a high spatial variability. With this focus, the aim of the study was to evaluate the variables affecting live aboveground forest biomass (AGB) in Subtropical Moist Forests of Southern Brazil, and to analyze the spatial distribution of biomass estimates. Data from a forest inventory performed in the State of Rio Grande do Sul, Southern Brazil, was used in the present study. Thirty-eight 1-ha plots were sampled and all trees with DBH > or = 9.5cm were included for biomass estimation. Values for aboveground biomass were obtained using published allometric equations. Environmental and biotic variables (elevation, rainfall, temperature, soils, stem density and species diversity) were obtained from the literature or calculated from the dataset. For the total dataset, mean AGB was 195.2 Mg/ha. Estimates differed between Broadleaf and Mixed Coniferous-Broadleaf forests: mean AGB was lower in Broadleaf Forests (AGB(BF)=118.9 Mg/ha) when compared to Mixed Forests (AGB(MF)=250.3 Mg/ha). There was a high spatial and local variability in our dataset, even within forest types. This condition is normal in tropical forests and is usually attributed to the presence of large trees. The explanatory multiple regressions were influenced mainly by elevation and explained 50.7% of the variation in AGB. Stem density, diversity and organic matter also influenced biomass variation. The results from our study showed a positive relationship between aboveground biomass and elevation. Therefore, higher values of AGB are located at higher elevations and subjected to cooler temperatures and wetter climate. There seems to be an important contribution of the coniferous species Araucaria angustifolia in Mixed Forest plots, as it presented

  3. Methane emissions from bald cypress tree trunks in a bottomland forest

    Science.gov (United States)

    Schile, L. M.; Pitz, S.; Megonigal, P.

    2013-12-01

    Studies on natural methane emissions predominantly have occurred on wetland soils with herbaceous plant species. Less attention, however, has been placed on the role of woody wetland plant species in the methane cycle. Recent studies on methane emissions from tree trunks document that they are a significant source of emissions that previously has been not accounted for. In this study, we examine methane emissions from trunks of mature bald cypress (Taxodium distichum), which is a dominant tree species in bottomland hardwood forests of the Southeastern United States. To date, little is known about soil methane emissions in these systems, and published tree emissions have been limited to a single study conducted on bald cypress knees. In May 2013, we established a plot in a monospecific bald cypress stand planted approximately 70 years ago on the Chesapeake Bay in Maryland and are monitoring methane emissions on 12 tree trunks, soil chambers, and pore-water over the course of a year. Custom-made 30 cm tall open face rectangular tree chambers were constructed out of white acrylic sheets and secured on each tree at a midpoint of 45 cm above the soil surface. Chambers were lined with neoprene along the tree surface and sealed with an epoxy. On three trees that varied in trunk diameter, chambers were placed at average heights of 95, 145, 195, and 345 cm from the soil surface in order to calculate a decay curve of methane emissions. Once a month, chambers were sealed with lids and head-space samples were collected over the course of an hour. Methane flux was calculated and compared to emissions from soil chambers. Average cypress trunk methane fluxes ranged from 17.7 μmole m-2 hr-1 in May to 49.5 and 116.5 μmole m-2 hr-1 in June and July, respectively. Soil fluxes averaged 28.5 μmole m-2 hr-1 in May and June, and decreased to 13.7 μmole m-2 hr-1 in July. Methane emissions decreased exponentially up the tree trunk, with fluxes of 2 μmole m-2 hr-1 and less calculated

  4. Housing shortages in urban regions: aggressive interactions at tree hollows in forest remnants.

    Directory of Open Access Journals (Sweden)

    Adrian Davis

    Full Text Available Urbanisation typically results in a reduction of hollow-bearing trees and an increase in the density of particularly species, potentially resulting in an increased level of competition as cavity-nesting species compete for a limited resource. To improve understanding of hollow usage between urban cavity-nesting species in Australia, particularly parrots, we investigated how the hollow-using assemblage, visitation rate, diversity and number of interactions varied between hollows within urban remnant forest and continuous forest. Motion-activated video cameras were installed, via roped access to the canopy, and hollow usage was monitored at 61 hollows over a two-year period. Tree hollows within urban remnants had a significantly different assemblage of visitors to those in continuous forest as well as a higher rate of visitation than hollows within continuous forest, with the rainbow lorikeet making significantly more visitations than any other taxa. Hollows within urban remnants were characterised by significantly higher usage rates and significantly more aggressive interactions than hollows within continuous forest, with parrots responsible for almost all interactions. Within urban remnants, high rates of hollow visitation and both interspecific and intraspecific interactions observed at tree hollows suggest the number of available optimal hollows may be limiting. Understanding the usage of urban remnant hollows by wildlife, as well as the role of parrots as a potential flagship for the conservation of tree-hollows, is vital to prevent a decrease in the diversity of urban fauna, particularly as other less competitive species risk being outcompeted by abundant native species.

  5. Reconstructing European forest management from 1600 to 2010

    NARCIS (Netherlands)

    McGrath, M.J.; Luyssaert, S.; Meyfroidt, P.; Kaplan, J.O.; Bürgi, M.; Chen, Y.; Erb, K.; Gimmi, U.; McInerney, D.; Naudts, K.; Otto, J.; Pasztor, F.; Ryder, J.; Schelhaas, M.J.; Valade, A.

    2015-01-01

    Because of the slow accumulation and long residence time of carbon in biomass and soils, the present state and future dynamics of temperate forests are influenced by management that took place centuries to millennia ago. Humans have exploited the forests of Europe for fuel, construction materials

  6. Sources of nitrous oxide emitted from European forest soils

    DEFF Research Database (Denmark)

    Ambus, P.; Zechmeister-Boltenstern, S.; Butterbach-Bahl, K.

    2006-01-01

    Forest ecosystems may provide strong sources of nitrous oxide (N2O), which is important for atmospheric chemical and radiative properties. Nonetheless, our understanding of controls on forest N2O emissions is insufficient to narrow current flux estimates, which still are associated with great...

  7. Can evolutionary constraints explain the rarity of nitrogen-fixing trees in high-latitude forests?

    Science.gov (United States)

    Menge, Duncan N L; Crews, Timothy E

    2016-09-01

    Contents 1195 I. 1195 II. 1196 III. 1196 IV. 1200 1200 References 1200 SUMMARY: The rarity of symbiotic nitrogen (N)-fixing trees in temperate and boreal ('high-latitude') forests is curious. One explanation - the evolutionary constraints hypothesis - posits that high-latitude N-fixing trees are rare because few have evolved. Here, we consider traits necessary for high-latitude N-fixing trees. We then use recent developments in trait evolution to estimate that > 2000 and > 500 species could have evolved from low-latitude N-fixing trees and high-latitude N-fixing herbs, respectively. Evolution of N-fixing from nonfixing trees is an unlikely source of diversity. Dispersal limitation seems unlikely to limit high-latitude N-fixer diversity. The greater number of N-fixing species predicted to evolve than currently inhabit high-latitude forests suggests a greater role for ecological than evolutionary constraints. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

  8. Spatial characteristics of tree diameter distributions in a temperate old-growth forest.

    Directory of Open Access Journals (Sweden)

    Chunyu Zhang

    Full Text Available This contribution identifies spatial characteristics of tree diameter in a temperate forest in north-eastern China, based on a fully censused observational study area covering 500×600 m. Mark correlation analysis with three null hypothesis models was used to determine departure from expectations at different neighborhood distances. Tree positions are clumped at all investigated scales in all 37 studied species, while the diameters of most species are spatially negatively correlated, especially at short distances. Interestingly, all three cases showing short-distance attraction of dbh marks are associated with light-demanding shrub species. The short-distance attraction of dbh marks indicates spatially aggregated cohorts of stems of similar size. The percentage of species showing significant dbh suppression peaked at a 4 m distance under the heterogeneous Poisson model. At scales exceeding the peak distance, the percentage of species showing significant dbh suppression decreases sharply with increasing distances. The evidence from this large observational study shows that some of the variation of the spatial characteristics of tree diameters is related variations of topography and soil chemistry. However, an obvious interpretation of this result is still lacking. Thus, removing competitors surrounding the target trees is an effective way to avoid neighboring competition effects reducing the growth of valuable target trees in forest management practice.

  9. Confronting a Process-based Model of Temperate Tree Transpiration with Data from Forests in Central Panama Exposed to Drought

    Science.gov (United States)

    Ewers, B. E.; Bretfeld, M.; Millar, D.; Hall, J. S.; Beverly, D.; Hall, J. S.; Ogden, F. L.; Mackay, D. S.

    2016-12-01

    Process-based models of tree impacts on the hydrologic cycle must include not only plant hydraulic limitations but also photosynthetic controls because plants lose water to gain carbon. The Terrestrial Regional Ecosystem Exchange Simulator (TREES) is one such model. TREES includes a Bayesian model-data fusion approach that provides rigorous tests of patterns in tree transpiration data against biophysical processes in the model. TREES has been extensively tested against many temperate tree data sets including those experiencing severe and lethal drought. We test TREES against data from sap flow-scaled transpiration in 76 tropical trees (representing 42 different species) in secondary forests of three different ages (8, 25, and 80+ years) located in the Panama Canal Watershed. These data were collected during the third driest El Niño-Southern Oscillation (ENSO) event on record in Panama during 2015/2016. Tree transpiration response to vapor pressure deficit and solar radiation was the same in the two older forests, but showed an additional response to limited soil moisture in the youngest forest. Volumetric water content at 30 and 50 cm depths was 8% lower in the 8 year old forest than in the 80+ year old forest. TREES could not simulate this difference in soil moisture without increasing simulated root area. TREES simulations were improved by including light response curves of leaf photosynthesis, root vulnerability to cavitation and canopy position impacts on light. TREES was able to simulate the anisohydric (loose stomatal regulation of leaf water potential) and isohydric (tight stomatal regulation) of the 73 trees species a priori indicating that species level information is not required. Analyses of posterior probability distributions indicates TREES model predictions of individual tree transpiration would likely be improved with more detailed root and soil moisture in all forest ages data with the most improvement likely in the 8 year old forest. Our results

  10. Disturbance regimes, gap-demanding trees and seed mass related to tree height in warm temperate rain forests worldwide.

    Science.gov (United States)

    Grubb, Peter J; Bellingham, Peter J; Kohyama, Takashi S; Piper, Frida I; Valido, Alfredo

    2013-08-01

    For tropical lowland rain forests, Denslow (1987) hypothesized that in areas with large-scale disturbances tree species with a high demand for light make up a larger proportion of the flora; results of tests have been inconsistent. There has been no test for warm temperate rain forests (WTRFs), but they offer a promising testing ground because they differ widely in the extent of disturbance. WTRF is dominated by microphylls sensu Raunkiaer and has a simpler structure and range of physiognomy than tropical or subtropical rain forests. It occurs in six parts of the world: eastern Asia, New Zealand, Chile, South Africa, SE Australia and the Azores. On the Azores it has been mostly destroyed, so we studied instead the subtropical montane rain forest (STMRF) on the Canary Islands which also represents a relict of the kind of WTRF that once stretched across southern Eurasia. We sought to find whether in these six regions the proportion of tree species needing canopy gaps for establishment reflects the frequency and/or extent of canopy disturbance by wind, landslide, volcanic eruptions (lava flow and ash fall), flood or fire. We used standard floras and ecological accounts to draw up lists of core tree species commonly reaching 5 m height. We excluded species which are very rare, very localized in distribution, or confined to special habitats, e.g. coastal forests or rocky sites. We used published accounts and our own experience to classify species into three groups: (1) needing canopy gaps for establishment; (2) needing either light shade throughout or a canopy gap relatively soon (a few months or years) after establishment; and (3) variously more shade-tolerant. Group 1 species were divided according the kind of canopy opening needed: tree-fall gap, landslide, lava flow, flood or fire. Only some of the significant differences in proportion of Group 1 species were consistent with differences in the extent of disturbance; even in some of those cases other factors seem

  11. Crown development in tropical rain forest trees: patterns with tree height and light availability

    NARCIS (Netherlands)

    Sterck, F.J.; Bongers, F.

    2001-01-01

    1 Monitoring of two canopy species Dicorynia guianensis and Vouacapoua americana (Caesalpiniaceae) in a tropical rain forest in French Guiana was used to investigate vegetative crown development at five organizational levels: leaf, metamer, extension unit, sympodial unit and whole crown. The effects

  12. ON THE USE OF SHORTWAVE INFRARED FOR TREE SPECIES DISCRIMINATION IN TROPICAL SEMIDECIDUOUS FOREST

    Directory of Open Access Journals (Sweden)

    M. P. Ferreira

    2015-08-01

    Full Text Available Tree species mapping in tropical forests provides valuable insights for forest managers. Keystone species can be located for collection of seeds for forest restoration, reducing fieldwork costs. However, mapping of tree species in tropical forests using remote sensing data is a challenge due to high floristic and spectral diversity. Little is known about the use of different spectral regions as most of studies performed so far used visible/near-infrared (390-1000 nm features. In this paper we show the contribution of shortwave infrared (SWIR, 1045-2395 nm for tree species discrimination in a tropical semideciduous forest. Using high-resolution hyperspectral data we also simulated WorldView-3 (WV-3 multispectral bands for classification purposes. Three machine learning methods were tested to discriminate species at the pixel-level: Linear Discriminant Analysis (LDA, Support Vector Machines with Linear (L-SVM and Radial Basis Function (RBF-SVM kernels, and Random Forest (RF. Experiments were performed using all and selected features from the VNIR individually and combined with SWIR. Feature selection was applied to evaluate the effects of dimensionality reduction and identify potential wavelengths that may optimize species discrimination. Using VNIR hyperspectral bands, RBF-SVM achieved the highest average accuracy (77.4%. Inclusion of the SWIR increased accuracy to 85% with LDA. The same pattern was also observed when WV-3 simulated channels were used to classify the species. The VNIR bands provided and accuracy of 64.2% for LDA, which was increased to 79.8 % using the new SWIR bands that are operationally available in this platform. Results show that incorporating SWIR bands increased significantly average accuracy for both the hyperspectral data and WorldView-3 simulated bands.

  13. Tree species partition N uptake by soil depth in boreal forests.

    Science.gov (United States)

    Houle, D; Moore, J D; Ouimet, R; Marty, C

    2014-05-01

    It is recognized that the coexistence of herbaceous species in N-depleted habitats can be facilitated by N partitioning; however, the existence of such a phenomenon for trees has not yet been demonstrated. Here, we show from both foliage and soil 15N natural abundance values and from a 12-year in situ 15N addition experiment, that black spruce (Picea mariana) and jack pine (Pinus banksiana), two widespread species of the Canadian boreal forest, take up N at different depths. While black spruce takes up N from the organic soil, jack pine acquires it deeper within the highly N-depleted mineral soil. Systematic difference in foliar 15N natural abundance between the two species across seven sites distributed throughout the eastern Canadian boreal forest shows that N spatial partitioning is a widespread phenomenon. Distinct relationships between delta15N and N concentration in leaves of both species further emphasize their difference in N acquisition strategies. This result suggests that such complementary mechanisms of N acquisition could facilitate tree species coexistence in such N-depleted habitats and could contribute to the positive biodiversity-productivity relationship recently revealed for the eastern Canadian boreal forest, where jack pine is present. It also has implications for forest management and provides new insights to interpret boreal forest regeneration following natural or anthropogenic perturbations.

  14. A window of opportunity for climate-change adaptation: Easing tree mortality by reducing forest basal area

    Science.gov (United States)

    Bradford, John B.; Bell, David M.

    2017-01-01

    Increasing aridity as a result of climate change is expected to exacerbate tree mortality. Reducing forest basal area – the cross-sectional area of tree stems within a given ground area – can decrease tree competition, which may reduce drought-induced tree mortality. However, neither the magnitude of expected mortality increases, nor the potential effectiveness of basal area reduction, has been quantified in dryland forests such as those of the drought-prone Southwest US. We used thousands of repeatedly measured forest plots to show that unusually warm and dry conditions are related to high tree mortality rates and that mortality is positively related to basal area. Those relationships suggest that while increasing high temperature extremes forecasted by climate models may lead to elevated tree mortality during the 21st century, future tree mortality might be partly ameliorated by reducing stand basal area. This adaptive forest management strategy may provide a window of opportunity for forest managers and policy makers to guide forest transitions to species and/or genotypes more suited to future climates.

  15. 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.

  16. 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.

  17. Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging.

    Science.gov (United States)

    Jucker, Tommaso; Sanchez, Aida Cuni; Lindsell, Jeremy A; Allen, Harriet D; Amable, Gabriel S; Coomes, David A

    2016-06-01

    Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) - one of the largest tracts of intact tropical moist forest in West Africa - to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers - with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long-lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old-growth tropical forests.

  18. Trees as bioindicator of heavy metal pollution in three European cities

    Energy Technology Data Exchange (ETDEWEB)

    Sawidis, T. [Department of Botany, University of Thessaloniki, 54124 Thessaloniki (Greece); Breuste, J., E-mail: juergen.breuste@sbg.ac.at [Department of Geography and Geology, University of Salzburg, 5010 Salzburg (Austria); Mitrovic, M.; Pavlovic, P. [Department of Ecology, Institute for Biological Research ' Sinisa Stankovic' , University of Belgrade, Bulevar despota Stefana 142, 11060 Belgrade (Serbia); Tsigaridas, K. [Department of Botany, University of Thessaloniki, 54124 Thessaloniki (Greece)

    2011-12-15

    Concentrations of four heavy metals were determined in tree leaves and bark collected from polluted and non-polluted areas of three European cities (Salzburg, Belgrade and Thessaloniki) for a comparative study. Platanus orientalis L. and Pinus nigra Arn., widespread in urban northern and southern Europe, were tested for their suitability for air quality biomonitoring. Leaves and barks were collected uniformly of an initial quantity of about 30 g of each sample. Analysis was accomplished by electrothermal atomic absorption spectrometry after total digestion. Site-dependent variations were found with the highest concentration level measured in Belgrade, followed by Thessaloniki and Salzburg. A higher accumulation of heavy metals was found in bark compared to leaves. Pine tree bark, accumulating higher concentrations of trace metals compared to plane tree bark, shows a higher efficiency as bioindicator for urban pollution. Both indicator species are suitable for comparative studies on bioindication of urban air pollution. - Highlights: > Oriental plane and Austrian pine are suitable for comparative urban air quality biomonitoring of heavy metal pollution. > Pine tree is excellently suitable as urban bioindicator as it accumulates high concentrations of trace metals. > The highest heavy metal pollution was found in Belgrade followed by Thessaloniki and Salzburg. - Oriental plane (Platanus orientalis L.) and Austrian pine (Pinus nigra Arn.), widespread in urban northern and southern Europe, are suitable for comparative biomonitoring of urban air pollution.

  19. Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

    DEFF Research Database (Denmark)

    Nabe-Nielsen, J.; Severiche, W.; Fredericksen, T.

    2007-01-01

    -eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some......Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north...

  20. Influence of Tree Species Composition and Community Structure on Carbon Density in a Subtropical Forest.

    Directory of Open Access Journals (Sweden)

    Yanqiu Hu

    Full Text Available We assessed the impact of species composition and stand structure on the spatial variation of forest carbon density using data collected from a 4-ha plot in a subtropical forest in southern China. We found that 1 forest biomass carbon density significantly differed among communities, reflecting a significant effect of community structure and species composition on carbon accumulation; 2 soil organic carbon density increased whereas stand biomass carbon density decreased across communities, indicating that different mechanisms might account for the accumulation of stand biomass carbon and soil organic carbon in the subtropical forest; and 3 a small number of tree individuals of the medium- and large-diameter class contributed predominantly to biomass carbon accumulation in the community, whereas a large number of seedlings and saplings were responsible for a small proportion of the total forest carbon stock. These findings demonstrate that both biomass carbon and soil carbon density in the subtropical forest are sensitive to species composition and community structure, and that heterogeneity in species composition and stand structure should be taken into account to ensure accurate forest carbon accounting.