Science.gov

Sample records for forest ecosystem final

  1. Managing pinon-juniper ecosystems for sustainability and social needs. Forest Service general technical report (Final)

    SciTech Connect

    Aldon, E.F.; Shaw, D.W.

    1993-10-01

    The purpose of the symposium was to assist the USDA Forest Service, other federal land management agencies, and the New Mexico State Land Office in the future development and management of the pinon-juniper ecosystem in the Southwest. Authors assessed the current state of knowledge about the pinon-juniper resources and helped develop future research and management goals.

  2. Forest ecosystems in the Alaskan taiga

    SciTech Connect

    Van Cleve, K.; Chapin, F.S. III; Flanagan, P.W.; Viereck, L.A.

    1986-01-01

    This volume in the series ''Ecological Studies'' provides an overview and synthesis of research on the structure and function of taiga forest ecosystems of interior Alaska. The first section discusses the nature of the taiga environment and covers climate, forest ecosystem distribution, natural regeneration of vegetation, and the role of fire. The second edition focuses on environmental controls over organism activity with discussions on growth and nutrient use, nitrogen fixation, physiological ecology of mosses, and microbial activity and element availability. The final section considers environmental controls over ecosystem processes with discussions of processes, plant-animal interactions, and a model of forest growth and yield.

  3. Evaluating the Contribution of Climate Forcing and Forest Dynamics to Accelerating Carbon Sequestration by Forest Ecosystems in the Northeastern U.S.: Final Report

    SciTech Connect

    Munger, J. William; Foster, David R.; Richardson, Andrew D.

    2014-10-01

    This report summarizes work to improve quantitative understanding of the terrestrial ecosystem processes that control carbon sequestration in unmanaged forests It builds upon the comprehensive long-term observations of CO2 fluxes, climate and forest structure and function at the Harvard Forest in Petersham, MA. This record includes the longest CO2 flux time series in the world. The site is a keystone for the AmeriFlux network. Project Description The project synthesizes observations made at the Harvard Forest HFEMS and Hemlock towers, which represent the dominant mixed deciduous and coniferous forest types in the northeastern United States. The 20+ year record of carbon uptake at Harvard Forest and the associated comprehensive meteorological and biometric data, comprise one of the best data sets to challenge ecosystem models on time scales spanning hourly, daily, monthly, interannual and multi-decadal intervals, as needed to understand ecosystem change and climate feedbacks.

  4. Carbon Isotopic Studies of Assimilated and Ecosystem Respired CO2 in a Southeastern Pine Forest. Final Report and Conference Proceedings

    SciTech Connect

    Conte, Maureen H

    2008-04-10

    Carbon dioxide is the major “greenhouse” gas responsible for global warming. Southeastern pine forests appear to be among the largest terrestrial sinks of carbon dioxide in the US. This collaborative study specifically addressed the isotopic signatures of the large fluxes of carbon taken up by photosynthesis and given off by respiration in this ecosystem. By measuring these isotopic signatures at the ecosystem level, we have provided data that will help to more accurately quantify the magnitude of carbon fluxes on the regional scale and how these fluxes vary in response to climatic parameters such as rainfall and air temperature. The focus of the MBL subcontract was to evaluate how processes operating at the physiological and ecosystem scales affects the resultant isotopic signature of plant waxes that are emitted as aerosols into the convective boundary layer. These wax aerosols provide a large-spatial scale integrative signal of isotopic discrimination of atmospheric carbon dioxide by terrestrial photosynthesis (Conte and Weber 2002). The ecosystem studies have greatly expanded of knowledge of wax biosynthetic controls on their isootpic signature The wax aerosol data products produced under this grant are directly applicable as input for global carbon modeling studies that use variations in the concentration and carbon isotopic composition of atmospheric carbon dioxide to quantify the magnitude and spatial and temporal patterns of carbon uptake on the global scale.

  5. Management to conserve forest ecosystems

    USGS Publications Warehouse

    Robbins, C.S.; McComb, William C.

    1984-01-01

    Historically, management of forests for wildlife has emphasized creation of openings and provision for a maximum of edge habitats. Wildlife managers have believed, quite logically, that increased sunlight enhances productivity among plants and insects, resulting in greater use by game animals and other wildlife. Recent studies comparing breeding bird populations of extensive forests with those of isolated woodlots have shown that the smaller woodlots, especially those under 35 ha (about 85 acres), lack many species that are typical of the larger tracts. The missing species can be predicted, and basically are the neotropical migrants. These long-distance migrants share several characteristics that make them especially vulnerable to reproductive failure in situations where predation and cowbird parasitism are high: they are primarily single-brooded, open nesters that lay small clutches on or near the ground. Edge habitats and forest openings attract cowbirds and predators. The edge species of birds, which are mostly permanent residents or short-distance migrants, are well adapted to survive and reproduce in small isolated woodlands without the benefit of special habitat management. The obligate forest interior species, on the other hand, are decreasing in those parts of North America where extensive forests are being replaced by isolated woodlands. If we are to preserve ecosystems intact for the benefit of future generations, and maintain a viable gene pool for the scarcer species, we must think in terms of retaining large, unbroken tracts of forest and of limiting disturbance in the more remote portions of these tracts.

  6. Acid Precipitation and the Forest Ecosystem

    ERIC Educational Resources Information Center

    Dochinger, Leon S.; Seliga, Thomas A.

    1975-01-01

    The First International Symposium on Acid Precipitation and the Forest Ecosystem dealt with the potential magnitude of the global effects of acid precipitation on aquatic ecosystems, forest soils, and forest vegetation. The problem is discussed in the light of atmospheric chemistry, transport, and precipitation. (Author/BT)

  7. Air pollutants effects on forest ecosystems

    SciTech Connect

    Not Available

    1985-01-01

    This book presents the papers given at a conference on the effects of acid rain on forests. The conference was sponsored by the National Acid Precipitation Assessment Program (NAPAP). Topics considered at the conference included the status of US research on acid deposition and its effects contributing factors to the decline of forests, evidence for effects on ecosystems, the effects of air pollutants on forest ecosystems in North America and Europe, forest management, and future scientific research programs and management approaches.

  8. Predicting the response of a temperate forest ecosystem to atmospheric CO{sub 2} increase. Final report, 1984--1995

    SciTech Connect

    Bazzaz, F.A.

    1995-12-31

    This document describes the most recent progress made in several areas of the project. Details of individual experiments in the following areas are provided: (1) the impact of soil volume on the physiological acclimation of temperate deciduous trees in elevated CO{sub 2}; (2) growth under elevated CO{sub 2}: the shape as well as the size of pots is important; (3) a survey of growth responses of temperate deciduous trees to elevated CO{sub 2}; (4) a survey of closely related birch species; (5) the response of temperate deciduous tress to CO{sub 2} in variable light and nutrients conditions; (6) elevated CO{sub 2} differentially alters the response of birch and maple seedlings to a moisture gradient; (7) population dynamics; (8) heat shock in elevated CO{sub 2}: is there a change in temperature sensitivity; (9) response of temperate deciduous trees to CO{sub 2} in variable light and nutrient conditions; (10) changes in tree community composition and their consequences to ecosystem productivity; and (11) species diversity and ecosystem response to carbon dioxide fertilization.

  9. Insect pest management in forest ecosystems

    NASA Astrophysics Data System (ADS)

    Dahlsten, Donald L.; Rowney, David L.

    1983-01-01

    Understanding the role of insects in forest ecosystems is vital to the development of environmentally and economically sound pest management strategies in forestry Most of the research on forest insects has been confined to phytophagous species associated with economically important tree species The roles of most other insects in forest environments have generally been ignored, including the natural enemies and associates of phytophagous species identified as being important In the past few years several investigations have begun to reevaluate the role of phytophagous species responsible for perturbation in forest ecosystems, and it appears that these species may be playing an important role in the primary productivity of those ecosystems Also, there is an increasing awareness that forest pest managers have been treating the symptoms and not the causes of the problems in the forest Many insect problems are associated with poor sites or sites where trees are growing poorly because of crowding As a result, there is considerable emphasis on the hazard rating of stands of trees for their susceptibility to various phytophagous insects The next step is to manipulate forest stands to make them less susceptible to forest pest complexes A thinning study in California is used as an example and shows that tree mortality in ponderosa pine ( Pinus ponderosa) attributable to the western pine beetle ( Dendroctonus brevicomis) can be reduced by commercial thinning to reduce stocking

  10. Neighbourhood-scale urban forest ecosystem classification.

    PubMed

    Steenberg, James W N; Millward, Andrew A; Duinker, Peter N; Nowak, David J; Robinson, Pamela J

    2015-11-01

    Urban forests are now recognized as essential components of sustainable cities, but there remains uncertainty concerning how to stratify and classify urban landscapes into units of ecological significance at spatial scales appropriate for management. Ecosystem classification is an approach that entails quantifying the social and ecological processes that shape ecosystem conditions into logical and relatively homogeneous management units, making the potential for ecosystem-based decision support available to urban planners. The purpose of this study is to develop and propose a framework for urban forest ecosystem classification (UFEC). The multifactor framework integrates 12 ecosystem components that characterize the biophysical landscape, built environment, and human population. This framework is then applied at the neighbourhood scale in Toronto, Canada, using hierarchical cluster analysis. The analysis used 27 spatially-explicit variables to quantify the ecosystem components in Toronto. Twelve ecosystem classes were identified in this UFEC application. Across the ecosystem classes, tree canopy cover was positively related to economic wealth, especially income. However, education levels and homeownership were occasionally inconsistent with the expected positive relationship with canopy cover. Open green space and stocking had variable relationships with economic wealth and were more closely related to population density, building intensity, and land use. The UFEC can provide ecosystem-based information for greening initiatives, tree planting, and the maintenance of the existing canopy. Moreover, its use has the potential to inform the prioritization of limited municipal resources according to ecological conditions and to concerns of social equity in the access to nature and distribution of ecosystem service supply.

  11. Interacting CO2 and O3 effects on litter production, chemistry and decomposition in an aggrading northern forest ecosystem: final report

    SciTech Connect

    Rihard L. Lindroth

    2004-08-03

    The overall purpose of this research was to evaluate the independent and interactive effects of elevated levels of CO{sub 2} and O{sub 3} on tree leaf litter quality and decomposition. This research was conducted at the Aspen FACE (Free Air CO{sub 2} Enrichment) facility near Rhinelander, Wisconsin. This research comprised one facet of a larger project assessing how CO{sub 2} and O{sub 3} pollutants will alter carbon sequestration and nutrient cycling in north temperate forest ecosystems.

  12. Aquatic biodiversity in forests: A weak link in ecosystem services resilience

    USGS Publications Warehouse

    Penaluna, Brooke E.; Olson, Deanna H.; Flitcroft, Rebecca L; Weber, Matthew A.; Bellmore, James R.; Wondzell, Steven M.; Dunham, Jason; Johnson, Sherri L.; Reeves, Gordon H.

    2016-01-01

    The diversity of aquatic ecosystems is being quickly reduced on many continents, warranting a closer examination of the consequences for ecological integrity and ecosystem services. Here we describe intermediate and final ecosystem services derived from aquatic biodiversity in forests. We include a summary of the factors framing the assembly of aquatic biodiversity in forests in natural systems and how they change with a variety of natural disturbances and human-derived stressors. We consider forested aquatic ecosystems as a multi-state portfolio, with diverse assemblages and life-history strategies occurring at local scales as a consequence of a mosaic of habitat conditions and past disturbances and stressors. Maintaining this multi-state portfolio of assemblages requires a broad perspective of ecosystem structure, various functions, services, and management implications relative to contemporary stressors. Because aquatic biodiversity provides multiple ecosystem services to forests, activities that compromise aquatic ecosystems and biodiversity could be an issue for maintaining forest ecosystem integrity. We illustrate these concepts with examples of aquatic biodiversity and ecosystem services in forests of northwestern North America, also known as Northeast Pacific Rim. Encouraging management planning at broad as well as local spatial scales to recognize multi-state ecosystem management goals has promise for maintaining valuable ecosystem services. Ultimately, integration of information from socio-ecological ecosystems will be needed to maintain ecosystem services derived directly and indirectly from forest aquatic biota.

  13. Hydrologic Modeling of Boreal Forest Ecosystems

    NASA Technical Reports Server (NTRS)

    Haddeland, I.; Lettenmaier, D. P.

    1995-01-01

    This study focused on the hydrologic response, including vegetation water use, of two test regions within the Boreal-Ecosystem-Atmosphere Study (BOREAS) region in the Canadian boreal forest, one north of Prince Albert, Saskatchewan, and the other near Thompson, Manitoba. Fluxes of moisture and heat were studied using a spatially distributed hydrology soil-vegetation-model (DHSVM).

  14. Neighbourhood-scale urban forest ecosystem classification.

    PubMed

    Steenberg, James W N; Millward, Andrew A; Duinker, Peter N; Nowak, David J; Robinson, Pamela J

    2015-11-01

    Urban forests are now recognized as essential components of sustainable cities, but there remains uncertainty concerning how to stratify and classify urban landscapes into units of ecological significance at spatial scales appropriate for management. Ecosystem classification is an approach that entails quantifying the social and ecological processes that shape ecosystem conditions into logical and relatively homogeneous management units, making the potential for ecosystem-based decision support available to urban planners. The purpose of this study is to develop and propose a framework for urban forest ecosystem classification (UFEC). The multifactor framework integrates 12 ecosystem components that characterize the biophysical landscape, built environment, and human population. This framework is then applied at the neighbourhood scale in Toronto, Canada, using hierarchical cluster analysis. The analysis used 27 spatially-explicit variables to quantify the ecosystem components in Toronto. Twelve ecosystem classes were identified in this UFEC application. Across the ecosystem classes, tree canopy cover was positively related to economic wealth, especially income. However, education levels and homeownership were occasionally inconsistent with the expected positive relationship with canopy cover. Open green space and stocking had variable relationships with economic wealth and were more closely related to population density, building intensity, and land use. The UFEC can provide ecosystem-based information for greening initiatives, tree planting, and the maintenance of the existing canopy. Moreover, its use has the potential to inform the prioritization of limited municipal resources according to ecological conditions and to concerns of social equity in the access to nature and distribution of ecosystem service supply. PMID:26311086

  15. Subcanopy Flux Measurements in Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Wolf, S.; Paul-Limoges, E.; Baldocchi, D. D.

    2015-12-01

    Eddy-covariance measurements of carbon dioxide, water vapour and energy provide direct evidence for the biosphere-atmosphere exchange at the ecosystem scale. Such continuous measurements are typically performed in the atmospheric surface layer above the canopy and integrate fluxes over the entire ecosystem within the footprint. Forest ecosystems, however, have complex vertical structures composed of several layers with different functional properties that are represented to a limited extend by above canopy measurements. Concurrent eddy-covariance measurements below canopy (subcanopy) can provide valuable insights on (1) understory processes, (2) their contributions to total ecosystem fluxes, and (3) the partitioning of component fluxes. Accordingly, there is a large potential for including standardized subcanopy forest measurements into large-scale measurement networks such as FLUXNET. However, our understanding of the performance and limitations for such measurements is still very limited. To gain a better understanding of subcanopy measurements, we conducted (I) a survey across FLUXNET on their availability, and (II) a literature review on published subcanopy measurements. Subsequently, we are preparing a standardized synthesis dataset on subcanopy measurements within FLUXNET. We will present the results from our survey, summarize the current process understanding, and discuss research priorities for concurrent below and above canopy eddy-covariance measurements.

  16. Impacts of elevated atmospheric CO(2) on forest trees and forest ecosystems: knowledge gaps.

    PubMed

    Karnosky, David F

    2003-06-01

    Atmospheric CO(2) is rising rapidly, and options for slowing the CO(2) rise are politically charged as they largely require reductions in industrial CO(2) emissions for most developed countries. As forests cover some 43% of the Earth's surface, account for some 70% of terrestrial net primary production (NPP), and are being bartered for carbon mitigation, it is critically important that we continue to reduce the uncertainties about the impacts of elevated atmospheric CO(2) on forest tree growth, productivity, and forest ecosystem function. In this paper, I review knowledge gaps and research needs on the effects of elevated atmospheric CO(2) on forest above- and below-ground growth and productivity, carbon sequestration, nutrient cycling, water relations, wood quality, phenology, community dynamics and biodiversity, antioxidants and stress tolerance, interactions with air pollutants, heterotrophic interactions, and ecosystem functioning. Finally, I discuss research needs regarding modeling of the impacts of elevated atmospheric CO(2) on forests.Even though there has been a tremendous amount of research done with elevated CO(2) and forest trees, it remains difficult to predict future forest growth and productivity under elevated atmospheric CO(2). Likewise, it is not easy to predict how forest ecosystem processes will respond to enriched CO(2). The more we study the impacts of increasing CO(2), the more we realize that tree and forest responses are yet largely uncertain due to differences in responsiveness by species, genotype, and functional group, and the complex interactions of elevated atmospheric CO(2) with soil fertility, drought, pests, and co-occurring atmospheric pollutants such as nitrogen deposition and O(3). Furthermore, it is impossible to predict ecosystem-level responses based on short-term studies of young trees grown without interacting stresses and in small spaces without the element of competition. Long-term studies using free-air CO(2) enrichment

  17. Impacts of elevated atmospheric CO(2) on forest trees and forest ecosystems: knowledge gaps.

    PubMed

    Karnosky, David F

    2003-06-01

    Atmospheric CO(2) is rising rapidly, and options for slowing the CO(2) rise are politically charged as they largely require reductions in industrial CO(2) emissions for most developed countries. As forests cover some 43% of the Earth's surface, account for some 70% of terrestrial net primary production (NPP), and are being bartered for carbon mitigation, it is critically important that we continue to reduce the uncertainties about the impacts of elevated atmospheric CO(2) on forest tree growth, productivity, and forest ecosystem function. In this paper, I review knowledge gaps and research needs on the effects of elevated atmospheric CO(2) on forest above- and below-ground growth and productivity, carbon sequestration, nutrient cycling, water relations, wood quality, phenology, community dynamics and biodiversity, antioxidants and stress tolerance, interactions with air pollutants, heterotrophic interactions, and ecosystem functioning. Finally, I discuss research needs regarding modeling of the impacts of elevated atmospheric CO(2) on forests.Even though there has been a tremendous amount of research done with elevated CO(2) and forest trees, it remains difficult to predict future forest growth and productivity under elevated atmospheric CO(2). Likewise, it is not easy to predict how forest ecosystem processes will respond to enriched CO(2). The more we study the impacts of increasing CO(2), the more we realize that tree and forest responses are yet largely uncertain due to differences in responsiveness by species, genotype, and functional group, and the complex interactions of elevated atmospheric CO(2) with soil fertility, drought, pests, and co-occurring atmospheric pollutants such as nitrogen deposition and O(3). Furthermore, it is impossible to predict ecosystem-level responses based on short-term studies of young trees grown without interacting stresses and in small spaces without the element of competition. Long-term studies using free-air CO(2) enrichment

  18. Ecosystem adaptation to scarce nutrient resources: Do forest ecosystems shift from acquisition to recycling of phosphorus?

    NASA Astrophysics Data System (ADS)

    Lang, F.; Kaupenjohann, M.

    2011-12-01

    Friederike Lang(1, Nicole Wellbrock(2, Martin Kaupenjohann(1 (1) Department of Soil Science, TU Berlin, 10587 Berlin, Germany; (2) vTI Eberswalde Agricultural food production is essential to our existence, yet we are using up the Earths stocks of phosphorus (P) for the fertilizer production (Cordell, 2009). Forest ecosystems that developed on marginal soil have developed highly efficient strategies for the uptake, usage and recycling of P, which might inspire solutions for the problem of P scarcity in agriculture. However, these efficient forest strategies are hardly investigated yet. Current literature concepts on the adaptation to low soil-P supply are mainly refined to individual organisms (e.g. the concept of uptake efficiency, Sattelmacher et al., 1994, and utilisation efficiency of plants, Compton and Cole, 1998). At the ecosystem level, however, low mineral-P supply requires an evolution of the system towards closed biogeochemical cycling (the concept of cycling efficiency). At the ecosystem level nutrient efficiency becomes rather a matter of transfer and distribution of resources among species, generations and soil components than of the capability of single organisms to acquire P sources. We plead for introducing the term ecosystem nutrition to cover this topic. Our general hypothesis is that P depletion of soils drives the development of forest ecosystems from geochemical P acquiring systems (mobilisation of P from the mineral phase) to biogeochemical P recycling systems (recycling of P from soil organic matter). We conclude that fundamental knowledge in the area of ecosystem nutrition is essential for forestry to mitigate the consequences of increasing N deposition, climate change and intensification of forest usage, which most likely interfere with essential nutrition strategies of forest ecosystems. Transfer of the knowledge on nutrition strategies and resource management of near-natural ecosystems to/in agricultural systems may finally contribute to

  19. Quantification of soil respiration in forest ecosystems across China

    NASA Astrophysics Data System (ADS)

    Song, Xinzhang; Peng, Changhui; Zhao, Zhengyong; Zhang, Zhiting; Guo, Baohua; Wang, Weifeng; Jiang, Hong; Zhu, Qiuan

    2014-09-01

    We collected 139 estimates of the annual forest soil CO2 flux and 173 estimates of the Q10 value (the temperature sensitivity) assembled from 90 published studies across Chinese forest ecosystems. We analyzed the annual soil respiration (Rs) rates and the temperature sensitivities of seven forest ecosystems, including evergreen broadleaf forests (EBF), deciduous broadleaf forests (DBF), broadleaf and needleleaf mixed forests (BNMF), evergreen needleleaf forests (ENF), deciduous needleleaf forests (DNF), bamboo forests (BF) and shrubs (SF). The results showed that the mean annual Rs rate was 33.65 t CO2 ha-1 year-1 across Chinese forest ecosystems. Rs rates were significantly different (P < 0.001) among the seven forest types, and were significantly and positively influenced by mean annual temperature (MAT), mean annual precipitation (MAP), and actual evapotranspiration (AET); but negatively affected by latitude and elevation. The mean Q10 value of 1.28 was lower than the world average (1.4-2.0). The Q10 values derived from the soil temperature at a depth of 5 cm varied among forest ecosystems by an average of 2.46 and significantly decreased with the MAT but increased with elevation and latitude. Moreover, our results suggested that an artificial neural network (ANN) model can effectively predict Rs across Chinese forest ecosystems. This study contributes to better understanding of Rs across Chinese forest ecosystems and their possible responses to global warming.

  20. Paying for Forest Ecosystem Services: Voluntary Versus Mandatory Payments.

    PubMed

    Roesch-McNally, Gabrielle E; Rabotyagov, Sergey S

    2016-03-01

    The emergence of new markets for forest ecosystem services can be a compelling opportunity for market diversification for private forest landowners, while increasing the provision of public goods from private lands. However, there is limited information available on the willingness-to-pay (WTP) for specific forest ecosystem services, particularly across different ecosystem market mechanisms. We utilize survey data from Oregon and Washington households to compare marginal WTP for forest ecosystem services and the total WTP for cost-effective bundles of forest ecosystem services obtained from a typical Pacific Northwest forest across two value elicitation formats representing two different ecosystem market mechanisms: an incentive-compatible choice experiment involving mandatory tax payments and a hypothetical private provision scenario modeled as eliciting contributions to the preferred forest management alternative via a provision point mechanism with a refund. A representative household's total WTP for the average forest management program was estimated at $217.59 per household/year under a mandatory tax mechanism and $160.44 per household/per year under a voluntary, crowdfunding-style, contribution mechanism; however, these estimates are not statistically different. Marginal WTP estimates were assessed for particular forest ecosystem service attributes including water quality, carbon storage, mature forest habitat, and public recreational access. This study finds that survey respondents place significant economic value on forest ecosystem services in both elicitation formats and that the distributions of the marginal WTP are not statistically significantly different. PMID:26661136

  1. Paying for Forest Ecosystem Services: Voluntary Versus Mandatory Payments

    NASA Astrophysics Data System (ADS)

    Roesch-McNally, Gabrielle E.; Rabotyagov, Sergey S.

    2016-03-01

    The emergence of new markets for forest ecosystem services can be a compelling opportunity for market diversification for private forest landowners, while increasing the provision of public goods from private lands. However, there is limited information available on the willingness-to-pay (WTP) for specific forest ecosystem services, particularly across different ecosystem market mechanisms. We utilize survey data from Oregon and Washington households to compare marginal WTP for forest ecosystem services and the total WTP for cost-effective bundles of forest ecosystem services obtained from a typical Pacific Northwest forest across two value elicitation formats representing two different ecosystem market mechanisms: an incentive-compatible choice experiment involving mandatory tax payments and a hypothetical private provision scenario modeled as eliciting contributions to the preferred forest management alternative via a provision point mechanism with a refund. A representative household's total WTP for the average forest management program was estimated at 217.59 per household/year under a mandatory tax mechanism and 160.44 per household/per year under a voluntary, crowdfunding-style, contribution mechanism; however, these estimates are not statistically different. Marginal WTP estimates were assessed for particular forest ecosystem service attributes including water quality, carbon storage, mature forest habitat, and public recreational access. This study finds that survey respondents place significant economic value on forest ecosystem services in both elicitation formats and that the distributions of the marginal WTP are not statistically significantly different.

  2. Paying for Forest Ecosystem Services: Voluntary Versus Mandatory Payments.

    PubMed

    Roesch-McNally, Gabrielle E; Rabotyagov, Sergey S

    2016-03-01

    The emergence of new markets for forest ecosystem services can be a compelling opportunity for market diversification for private forest landowners, while increasing the provision of public goods from private lands. However, there is limited information available on the willingness-to-pay (WTP) for specific forest ecosystem services, particularly across different ecosystem market mechanisms. We utilize survey data from Oregon and Washington households to compare marginal WTP for forest ecosystem services and the total WTP for cost-effective bundles of forest ecosystem services obtained from a typical Pacific Northwest forest across two value elicitation formats representing two different ecosystem market mechanisms: an incentive-compatible choice experiment involving mandatory tax payments and a hypothetical private provision scenario modeled as eliciting contributions to the preferred forest management alternative via a provision point mechanism with a refund. A representative household's total WTP for the average forest management program was estimated at $217.59 per household/year under a mandatory tax mechanism and $160.44 per household/per year under a voluntary, crowdfunding-style, contribution mechanism; however, these estimates are not statistically different. Marginal WTP estimates were assessed for particular forest ecosystem service attributes including water quality, carbon storage, mature forest habitat, and public recreational access. This study finds that survey respondents place significant economic value on forest ecosystem services in both elicitation formats and that the distributions of the marginal WTP are not statistically significantly different.

  3. Whole-ecosystem experimental manipulations of tropical forests.

    PubMed

    Fayle, Tom M; Turner, Edgar C; Basset, Yves; Ewers, Robert M; Reynolds, Glen; Novotny, Vojtech

    2015-06-01

    Tropical forests are highly diverse systems involving extraordinary numbers of interactions between species, with each species responding in a different way to the abiotic environment. Understanding how these systems function and predicting how they respond to anthropogenic global change is extremely challenging. We argue for the necessity of 'whole-ecosystem' experimental manipulations, in which the entire ecosystem is targeted, either to reveal the functioning of the system in its natural state or to understand responses to anthropogenic impacts. We survey the current range of whole-ecosystem manipulations, which include those targeting weather and climate, nutrients, biotic interactions, human impacts, and habitat restoration. Finally we describe the unique challenges and opportunities presented by such projects and suggest directions for future experiments.

  4. Whole-ecosystem experimental manipulations of tropical forests.

    PubMed

    Fayle, Tom M; Turner, Edgar C; Basset, Yves; Ewers, Robert M; Reynolds, Glen; Novotny, Vojtech

    2015-06-01

    Tropical forests are highly diverse systems involving extraordinary numbers of interactions between species, with each species responding in a different way to the abiotic environment. Understanding how these systems function and predicting how they respond to anthropogenic global change is extremely challenging. We argue for the necessity of 'whole-ecosystem' experimental manipulations, in which the entire ecosystem is targeted, either to reveal the functioning of the system in its natural state or to understand responses to anthropogenic impacts. We survey the current range of whole-ecosystem manipulations, which include those targeting weather and climate, nutrients, biotic interactions, human impacts, and habitat restoration. Finally we describe the unique challenges and opportunities presented by such projects and suggest directions for future experiments. PMID:25896491

  5. Ca isotope cycling in a forested ecosystem

    NASA Astrophysics Data System (ADS)

    Holmden, Chris; Bélanger, Nicolas

    2010-02-01

    Reports of large Ca isotope fractionations between trees and soils prompted this study of a Boreal forest ecosystem near La Ronge, Saskatchewan, to improve understanding of this phenomenon. The results on five tree species (black spruce, trembling aspen, white spruce, jack pine, balsam poplar) confirm that nutrient Ca uptake by plants favors the light isotopes, thus driving residual Ca in plant available soil pools towards enrichment in the heavy isotopes. Substantial within-tree fraction occurs in tissues formed along the transpiration stream, with low δ 44Ca values in fine roots (2 mm), intermediate values in stemwood, and high values in foliage. Separation factors between different plant tissues are similar between species, but the initial fractionation step in the tips of the fine roots is species specific, and/or sensitive to the local soil environment. Soil water δ 44Ca values appear to increase with depth to at least 35 cm below the top of the forest floor, which is close to the deepest level of fine roots. The heavy plant fractionated signature of Ca in the finely rooted upper soils filters downward where it is retained on ion exchange sites, leached into groundwater, and discharged into surface waters. The relationship between Ca uptake by tree fine roots and the pattern of δ 44Ca enrichment with soil depth was modeled for two Ca pools: the forest floor (litter) and the underlying (upper B) mineral soil. Six study plots were investigated along two hillside toposequences trending upwards from a first order stream. We used allometric equations describing the Ca distribution in boreal tree species to calculate weighted average δ 44Ca values for the stands in each plot and estimate Ca uptake rates. The δ 44Ca value of precipitation was measured, and soil weathering signatures deduced, by acid leaching of lower B mineral soils. Steady state equations were used to derive a set of model Ca fluxes and fractionation factors for each plot. The model reproduces

  6. Linking ecosystem characteristics to final ecosystem services for public policy

    PubMed Central

    Wong, Christina P; Jiang, Bo; Kinzig, Ann P; Lee, Kai N; Ouyang, Zhiyun

    2015-01-01

    Governments worldwide are recognising ecosystem services as an approach to address sustainability challenges. Decision-makers need credible and legitimate measurements of ecosystem services to evaluate decisions for trade-offs to make wise choices. Managers lack these measurements because of a data gap linking ecosystem characteristics to final ecosystem services. The dominant method to address the data gap is benefit transfer using ecological data from one location to estimate ecosystem services at other locations with similar land cover. However, benefit transfer is only valid once the data gap is adequately resolved. Disciplinary frames separating ecology from economics and policy have resulted in confusion on concepts and methods preventing progress on the data gap. In this study, we present a 10-step approach to unify concepts, methods and data from the disparate disciplines to offer guidance on overcoming the data gap. We suggest: (1) estimate ecosystem characteristics using biophysical models, (2) identify final ecosystem services using endpoints and (3) connect them using ecological production functions to quantify biophysical trade-offs. The guidance is strategic for public policy because analysts need to be: (1) realistic when setting priorities, (2) attentive to timelines to acquire relevant data, given resources and (3) responsive to the needs of decision-makers. PMID:25394857

  7. Linking ecosystem characteristics to final ecosystem services for public policy.

    PubMed

    Wong, Christina P; Jiang, Bo; Kinzig, Ann P; Lee, Kai N; Ouyang, Zhiyun

    2015-01-01

    Governments worldwide are recognising ecosystem services as an approach to address sustainability challenges. Decision-makers need credible and legitimate measurements of ecosystem services to evaluate decisions for trade-offs to make wise choices. Managers lack these measurements because of a data gap linking ecosystem characteristics to final ecosystem services. The dominant method to address the data gap is benefit transfer using ecological data from one location to estimate ecosystem services at other locations with similar land cover. However, benefit transfer is only valid once the data gap is adequately resolved. Disciplinary frames separating ecology from economics and policy have resulted in confusion on concepts and methods preventing progress on the data gap. In this study, we present a 10-step approach to unify concepts, methods and data from the disparate disciplines to offer guidance on overcoming the data gap. We suggest: (1) estimate ecosystem characteristics using biophysical models, (2) identify final ecosystem services using endpoints and (3) connect them using ecological production functions to quantify biophysical trade-offs. The guidance is strategic for public policy because analysts need to be: (1) realistic when setting priorities, (2) attentive to timelines to acquire relevant data, given resources and (3) responsive to the needs of decision-makers.

  8. Ca isotopic fractionation patterns in forest ecosystems

    NASA Astrophysics Data System (ADS)

    Kurtz, A. C.; Takagi, K.

    2012-12-01

    Calcium stable isotope ratios are an emerging tracer of the biogeochemical cycle of Ca that are just beginning to see significant application to forest ecosystems. The primary source of isotopic fractionation in these systems is discrimination against light Ca during uptake by plant roots. Cycling of vegetation-fractionated Ca establishes isotopically distinct Ca pools within a forest ecosystem. In some systems, the shallow soil exchangeable Ca pool is isotopically heavy relative to Ca inputs. This has been explained by preferential removal of light Ca from the soil. In other systems, the soil exchange pool is isotopically light relative to inputs, which is explained by recycling of plant-fractionated light Ca back into soil. Thus vegetation uptake of light Ca has been called on to account for both isotopically heavy and light Ca in the shallow soil exchange pools. We interpret patterns in ecosystem δ44Ca with the aid of a simple box model of the forest Ca cycle. We suggest that the δ44Ca of exchangeable Ca in the shallow soil pool primarily reflects the relative magnitude of three key fluxes in a forest Ca cycle, 1) the flux of external Ca into the system via weathering or atmospheric deposition, 2) the uptake flux of Ca from soils into the vegetation pool, and 3) the return flux of Ca to shallow soils via remineralization of leaf litter. Two observations that emerge from our model may aid in the application of Ca isotopes to provide insight into the forest Ca cycle. First, regardless of the magnitude of both vegetation Ca uptake and isotopic fractionation, the δ44Ca of the soil exchange pool will equal the input δ44Ca unless the plant uptake and remineralization fluxes are out of balance. A second observation is that the degree to which the shallow soil exchange pool δ44Ca can differ from the input ratio is controlled by the relative rates of biological uptake and external Ca input. Significant differences between soil exchange and input δ44Ca are seen only

  9. Forest ecosystem services of changbai mountain in china.

    PubMed

    Wu, Gang; Xiao, Han; Zhao, Jingzhu; Shao, Guofan; Li, Jing

    2002-02-01

    The forest ecosystem of the Changbai Mountain is the most typical upland temperate forest ecosystem in eastern Asia. It is also of the most primitive vegetation type that came into being through the natural succession of soil and vegetation following volcanic eruption. The forest ecosystem has great importance for maintaining the structures and functions of the watershed ecosystems of the Songhua River, the Yalu River and the Tumen River. We combined physical assessment method (PAM) with the value assessment method (VAM) to evaluate the forest ecosystem services of the northern slope of the, including eco-tourism, forest by-products, timber, soil and water conservation, air purification, and the recycling of nutritive elements. We also assessed the integrated forest ecosystem service and analyzed its dynamics. The service value provided by the Changbai Mountain forest ecosystem amounts up to RMB 3.38 x 10(12) yuan, of which, water conservation is 66%, water conservation and air purification together make up 80%, while the timber value is only 7%. Therefore, developing the ecosystem services besides timber is the best way to exert the integrated value of the forest ecosystem services of Changbai Mountain. PMID:18763060

  10. Forest ecosystem services of changbai mountain in china.

    PubMed

    Wu, Gang; Xiao, Han; Zhao, Jingzhu; Shao, Guofan; Li, Jing

    2002-02-01

    The forest ecosystem of the Changbai Mountain is the most typical upland temperate forest ecosystem in eastern Asia. It is also of the most primitive vegetation type that came into being through the natural succession of soil and vegetation following volcanic eruption. The forest ecosystem has great importance for maintaining the structures and functions of the watershed ecosystems of the Songhua River, the Yalu River and the Tumen River. We combined physical assessment method (PAM) with the value assessment method (VAM) to evaluate the forest ecosystem services of the northern slope of the, including eco-tourism, forest by-products, timber, soil and water conservation, air purification, and the recycling of nutritive elements. We also assessed the integrated forest ecosystem service and analyzed its dynamics. The service value provided by the Changbai Mountain forest ecosystem amounts up to RMB 3.38 x 10(12) yuan, of which, water conservation is 66%, water conservation and air purification together make up 80%, while the timber value is only 7%. Therefore, developing the ecosystem services besides timber is the best way to exert the integrated value of the forest ecosystem services of Changbai Mountain.

  11. Northern Forest Ecosystem Dynamics Using Coupled Models and Remote Sensing

    NASA Technical Reports Server (NTRS)

    Ranson, K. J.; Sun, G.; Knox, R. G.; Levine, E. R.; Weishampel, J. F.; Fifer, S. T.

    1999-01-01

    Forest ecosystem dynamics modeling, remote sensing data analysis, and a geographical information system (GIS) were used together to determine the possible growth and development of a northern forest in Maine, USA. Field measurements and airborne synthetic aperture radar (SAR) data were used to produce maps of forest cover type and above ground biomass. These forest attribute maps, along with a conventional soils map, were used to identify the initial conditions for forest ecosystem model simulations. Using this information along with ecosystem model results enabled the development of predictive maps of forest development. The results obtained were consistent with observed forest conditions and expected successional trajectories. The study demonstrated that ecosystem models might be used in a spatial context when parameterized and used with georeferenced data sets.

  12. [A review on carbon and water interactions of forest ecosystem and its impact factors].

    PubMed

    Song, Chun-lin; Sun, Xiang-yang; Wang, Gen-xu

    2015-09-01

    Interaction between carbon and water in forest ecosystem is a coupling process in terrestrial ecosystem, which is an indispensable aspect for the study of forest carbon pool, ecohydrological processes and the responses to global change. In the context of global change, the interaction and coupling of carbon and water in forest ecosystem has attracted much attention among scientists. In this paper, we reviewed the process mechanism of forest carbon and water relationships based on previous studies, which consisted of advance in forest water use efficiency, carbon and water interactions at different scales, scaling, and model simulation. We summed up the factors affecting for- est water and carbon interaction, including water condition, carbon dioxide enrichment, warming, nitrogen deposition, ozone concentration variation, solar radiation, and altitudinal gradients. Finally, we discussed the problems in the previous studies, and prospected the possible future research fields, among which we thought the inherent dynamics mechanism and scaling of forest carbon and water interactions should be enhanced.

  13. [Evaluation of economic forest ecosystem services in China].

    PubMed

    Wang, Bing; Lu, Shao-Wei

    2009-02-01

    This paper quantitatively evaluated the economic forest ecosystem services in the provinces of China in 2003, based on the long-term and continuous observations of economic forest ecosystems in this country, the sixth China national forest resources inventory data, and the price parameter data from the authorities in the world, and by applying the law of market value, the method of substitution of the expenses, and the law of the shadow project. The results showed that in 2003, the total value of economic forest ecosystem services in China was 11763.39 x 10(8) yuan, and the total value of the products from economic forests occupied 19.3% of the total ecosystem services value, which indicated that the economic forests not only provided society direct products, but also exhibited enormous eco-economic value. The service value of the functions of economic forests was in the order of water storage > C fixation and O2 release > biodiversity conservation > erosion control > air quality purification > nutrient cycle. The spatial pattern of economic forest ecosystem services in the provinces of China had the same trend with the spatial distribution of water and heat resources and biodiversity. To understand the differences of economic forest ecosystem services in the provinces of China was of significance in alternating the irrational arrangement of our present forestry production, diminishing the abuses of forest management, and establishing high grade, high efficient, and modernized economic forests.

  14. Interannual Variations in Ecosystem Oxidative Ratio in Croplands, Deciduous Forest, Coniferous Forest, and Early Successional Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Masiello, C. A.; Hockaday, W. C.; Gallagher, M. E.; Calligan, L.

    2009-12-01

    Ecosystem net primary productivity (NPP) can vary significantly with annual variations in precipitation and temperature. These climate variations can also drive changes in plant carbon allocation patterns. Shifting allocation patterns can lead to variation in net ecosystem biochemical stocks (e.g. kg cellulose, lignin, protein, and lipid/ha), which can in turn lead to shifts in ecosystem oxidative ratio (OR). OR is the molar ratio of O2 released : CO2 fixed during biosynthesis. Major plant biochemicals vary substantially in oxidative ratio, ranging from average organic acid OR values of 0.75 to average lipid OR values of 1.37 (Masiello et al., 2008). OR is a basic property of ecosystem biochemistry, and is also an essential variable needed to constrain the size of the terrestrial biospheric carbon sink (Keeling et al., 1996). OR is commonly assumed to be 1.10 (e.g. Prentice et al., 2001), but small variations in net ecosystem OR can drive large errors in estimates of the size of the terrestrial carbon sink (Randerson et al., 2006). We hypothesized that interannual changes in climate may drive interannual variation in ecosystem OR values. Working at Kellogg Biological Station NSF LTER, we measured the annual average OR of coniferous and deciduous forests, an early successional forest, and croplands under both corn and soy. There are clear distinctions between individual ecosystems (e.g., the soy crops have a higher OR than the corn crops, and the coniferous forests have a higher OR than the deciduous forests), but the ecosystems themselves retained remarkably constant annual OR values between 1998 and 2008.

  15. Urban forests and pollution mitigation: analyzing ecosystem services and disservices.

    PubMed

    Escobedo, Francisco J; Kroeger, Timm; Wagner, John E

    2011-01-01

    The purpose of this paper is to integrate the concepts of ecosystem services and disservices when assessing the efficacy of using urban forests for mitigating pollution. A brief review of the literature identifies some pollution mitigation ecosystem services provided by urban forests. Existing ecosystem services definitions and typologies from the economics and ecological literature are adapted and applied to urban forest management and the concepts of ecosystem disservices from natural and semi-natural systems are discussed. Examples of the urban forest ecosystem services of air quality and carbon dioxide sequestration are used to illustrate issues associated with assessing their efficacy in mitigating urban pollution. Development of urban forest management alternatives that mitigate pollution should consider scale, contexts, heterogeneity, management intensities and other social and economic co-benefits, tradeoffs, and costs affecting stakeholders and urban sustainability goals.

  16. Complex trophic interactions in kelp forest ecosystems

    USGS Publications Warehouse

    Estes, J. A.; Danner, E.M.; Doak, D.F.; Konar, B.; Springer, A.M.; Steinberg, P.D.; Tinker, M. Tim; Williams, T.M.

    2004-01-01

    The distributions and abundances of species and populations change almost continuously. Understanding the processes responsible is perhaps ecology’s most fundamental challenge. Kelp-forest ecosystems in southwest Alaska have undergone several phase shifts between alga- and herbivore-dominated states in recent decades. Overhunting and recovery of sea otters caused the earlier shifts. Studies focusing on these changes demonstrate the importance of top-down forcing processes, a variety of indirect food-web interactions associated with the otter-urchin-kelp trophic cascade, and the role of food-chain length in the coevolution of defense and resistance in plants and their herbivores. This system unexpectedly shifted back to an herbivore-dominated state during the 1990s, because of a sea-otter population collapse that apparently was driven by increased predation by killer whales. Reasons for this change remain uncertain but seem to be linked to the whole-sale collapse of marine mammals in the North Pacific Ocean and southern Bering Sea. We hypothesize that killer whales sequentially "fished down" pinniped and sea-otter populations after their earlier prey, the great whales, were decimated by commercial whaling. The dynamics of kelp forests in southwest Alaska thus appears to have been influenced by an ecological chain reaction that encompassed numerous species and large scales of space and time.

  17. Forest ecosystems: Vegetation, disturbance, and economics: Chapter 5

    USGS Publications Warehouse

    Littell, Jeremy S.; Hicke, Jeffrey A.; Shafer, Sarah L.; Capalbo, Susan M.; Houston, Laurie L.; Glick, Patty

    2013-01-01

    Forests cover about 47% of the Northwest (NW–Washington, Oregon, and Idaho) (Smith et al. 2009, fig. 5.1, table 5.1). The impacts of current and future climate change on NW forest ecosystems are a product of the sensitivities of ecosystem processes to climate and the degree to which humans depend on and interact with those systems. Forest ecosystem structure and function, particularly in relatively unmanaged forests where timber harvest and other land use have smaller effects, is sensitive to climate change because climate has a strong influence on ecosystem processes. Climate can affect forest structure directly through its control of plan physiology and life history (establishment, individual growth, productivity, and morality) or indirectly through its control of disturbance (fire, insects, disease). As climate changes, many forest processes will be affected, altering ecosystem services such as timber production and recreation. These changes have socioeconomic implications (e.g. for timber economies) and will require changes to current management of forests. Climate and management will interact to determine the forests of the future, and the scientific basis for adaptation to climate change in forests thus depends significantly on how forests will be affected.

  18. Forest Ecosystem Services and Eco-Compensation Mechanisms in China

    NASA Astrophysics Data System (ADS)

    Deng, Hongbing; Zheng, Peng; Liu, Tianxing; Liu, Xin

    2011-12-01

    Forests are a major terrestrial ecosystem providing multiple ecosystem services. However, the importance of forests is frequently underestimated from an economic perspective because of the externalities and public good properties of these services. Forest eco-compensation is a transfer mechanism that serves to internalize the externalities of forest ecosystem services by compensating individuals or companies for the losses or costs resulting from the provision of these services. China's current forest eco-compensation system is centered mainly on noncommercial forest. The primary measures associated with ecosystem services are (1) a charge on destructive activities, such as indiscriminate logging, and (2) compensation for individual or local activities and investments in forest conservation. The Compensation Fund System for Forest Ecological Benefits was first listed in the Forest Law of the People's Republic of China in 1998. In 2004, the Central Government Financial Compensation Fund, an important source for the Compensation Fund for Forest Ecological Benefits, was formally established. To improve the forest eco-compensation system, it is crucial to design and establish compensation criteria for noncommercial forests. These criteria should take both theoretical and practical concerns into account, and they should be based on the quantitative valuation of ecosystem services. Although some initial headway has been made on this task, the implementation of an effective forest eco-compensation system in China still has deficiencies and still faces problems. Implementing classification-based and dynamic management for key noncommercial forests and establishing an eco-compensation mechanism with multiple funding sources in the market economy are the key measures needed to conquer these problems and improve the forest eco-compensation system and China's forestry development in sequence.

  19. Maintaining ecosystem function and services in logged tropical forests.

    PubMed

    Edwards, David P; Tobias, Joseph A; Sheil, Douglas; Meijaard, Erik; Laurance, William F

    2014-09-01

    Vast expanses of tropical forests worldwide are being impacted by selective logging. We evaluate the environmental impacts of such logging and conclude that natural timber-production forests typically retain most of their biodiversity and associated ecosystem functions, as well as their carbon, climatic, and soil-hydrological ecosystem services. Unfortunately, the value of production forests is often overlooked, leaving them vulnerable to further degradation including post-logging clearing, fires, and hunting. Because logged tropical forests are extensive, functionally diverse, and provide many ecosystem services, efforts to expand their role in conservation strategies are urgently needed. Key priorities include improving harvest practices to reduce negative impacts on ecosystem functions and services, and preventing the rapid conversion and loss of logged forests. PMID:25092495

  20. Maintaining ecosystem function and services in logged tropical forests.

    PubMed

    Edwards, David P; Tobias, Joseph A; Sheil, Douglas; Meijaard, Erik; Laurance, William F

    2014-09-01

    Vast expanses of tropical forests worldwide are being impacted by selective logging. We evaluate the environmental impacts of such logging and conclude that natural timber-production forests typically retain most of their biodiversity and associated ecosystem functions, as well as their carbon, climatic, and soil-hydrological ecosystem services. Unfortunately, the value of production forests is often overlooked, leaving them vulnerable to further degradation including post-logging clearing, fires, and hunting. Because logged tropical forests are extensive, functionally diverse, and provide many ecosystem services, efforts to expand their role in conservation strategies are urgently needed. Key priorities include improving harvest practices to reduce negative impacts on ecosystem functions and services, and preventing the rapid conversion and loss of logged forests.

  1. Anthropogenic impacts on tropical forest biodiversity: a network structure and ecosystem functioning perspective

    PubMed Central

    Morris, Rebecca J.

    2010-01-01

    Huge areas of diverse tropical forest are lost or degraded every year with dramatic consequences for biodiversity. Deforestation and fragmentation, over-exploitation, invasive species and climate change are the main drivers of tropical forest biodiversity loss. Most studies investigating these threats have focused on changes in species richness or species diversity. However, if we are to understand the absolute and long-term effects of anthropogenic impacts on tropical forests, we should also consider the interactions between species, how those species are organized in networks, and the function that those species perform. I discuss our current knowledge of network structure and ecosystem functioning, highlighting empirical examples of their response to anthropogenic impacts. I consider the future prospects for tropical forest biodiversity, focusing on biodiversity and ecosystem functioning in secondary forest. Finally, I propose directions for future research to help us better understand the effects of anthropogenic impacts on tropical forest biodiversity. PMID:20980318

  2. [Forest ecosystem service and its evaluation in China].

    PubMed

    Fang, Jin; Lu, Shaowei; Yu, Xinxiao; Rao, Liangyi; Niu, Jianzhi; Xie, Yuanyuan; Zhag, Zhenming

    2005-08-01

    Facing the relative lag of forest ecosystem service and estimation in China, this paper proposed to quickly carry out the research on the evaluation of forest ecosystem service. On the basis of the classification of forest ecosystem types in China, the service of artificial and semi-artificial forest ecosystems was investigated, which was divided into eight types, i.e., timber and other products, recreation and eco-tourism, water storage, C fixation and O2 release, nutrient cycling, air quality purifying, erosion control, and habitat provision. According to the assessment index system for global ecosystem service proposed by Costanza et al., a series of assessment index system suitable for Chinese forest ecosystem service was set up, by which, the total value of forest ecosystem service in China was estimated to be 30 601.20 x 10(8) yuan x yr(-1), including direct and indirect economic value about 1 920.23 x 10(8) and 28 680.97 x 10(8) yuan x yr(-1), respectively. The indirect value was as 14.94 times as the direct one. The research aimed to bring natural resources and environment factors into the account system of national economy quickly, and to realize the green GDP at last, which would be helpful to realize sustainable development and environment protection.

  3. Nitrogen cycling and nitrogen saturation in temperate forest ecosystems.

    PubMed

    Aber, J D

    1992-07-01

    The last decade has seen a dramatic shift in the focus of nitrogen cycling research in forest ecosystems. Concerns over nitrogen deficiencies and effects of removal in harvest have given way to concerns over excess nitrogen availability and the potential for forest decline and surface water pollution. Driving this paradigm shift is the increase in atmospheric deposition of nitrogen to forests due to industrial and agricultural activity. At the core of the new paradigm is the concept of 'nitrogen saturation' of forest ecosystems. The purpose of this review is to synthesize recent advances in research relating to nitrogen deposition effects on temperate zone forest ecosystems, and the further effects of nitrogen saturation on environmental quality. PMID:21236013

  4. A tool for assessing ecological status of forest ecosystem

    NASA Astrophysics Data System (ADS)

    Rahman Kassim, Abd; Afizzul Misman, Muhammad; Azahari Faidi, Mohd; Omar, Hamdan

    2016-06-01

    Managers and policy makers are beginning to appreciate the value of ecological monitoring of artificially regenerated forest especially in urban areas. With the advent of more advance technology in precision forestry, high resolution remotely sensed data e.g. hyperspectral and LiDAR are becoming available for rapid and precise assessment of the forest condition. An assessment of ecological status of forest ecosystem was developed and tested using FRIM campus forest stand. The forest consisted of three major blocks; the old growth artificially regenerated native species forests, naturally regenerated forest and recent planted forest for commercial timber and other forest products. Our aim is to assess the ecological status and its proximity to the mature old growth artificially regenerated stand. We used airborne LiDAR, orthophoto and thirty field sampling quadrats of 20x20m for ground verification. The parameter assessments were grouped into four broad categories: a. forest community level-composition, structures, function; landscape structures-road network and forest edges. A metric of parameters and rating criteria was introduced as indicators of the forest ecological status. We applied multi-criteria assessment to categorize the ecological status of the forest stand. The paper demonstrates the application of the assessment approach using FRIM campus forest as its first case study. Its potential application to both artificially and naturally regenerated forest in the variety of Malaysian landscape is discussed

  5. 77 FR 60373 - Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and Piute...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-03

    ... Forest Service Monroe Mountain Aspen Ecosystems Restoration Project Fishlake National Forest; Sevier and... alternatives, within the Monroe Mountain Aspen Ecosystems Restoration Project area. The purpose of the Monroe Mountain Aspen Ecosystems Restoration Project is to implement land management activities that...

  6. Ecosystem services capacity across heterogeneous forest types: understanding the interactions and suggesting pathways for sustaining multiple ecosystem services.

    PubMed

    Alamgir, Mohammed; Turton, Stephen M; Macgregor, Colin J; Pert, Petina L

    2016-10-01

    As ecosystem services supply from tropical forests is declining due to deforestation and forest degradation, much effort is essential to sustain ecosystem services supply from tropical forested landscapes, because tropical forests provide the largest flow of multiple ecosystem services among the terrestrial ecosystems. In order to sustain multiple ecosystem services, understanding ecosystem services capacity across heterogeneous forest types and identifying certain ecosystem services that could be managed to leverage positive effects across the wider bundle of ecosystem services are required. We sampled three forest types, tropical rainforests, sclerophyll forests, and rehabilitated plantation forests, over an area of 32,000m(2) from Wet Tropics bioregion, Australia, aiming to compare supply and evaluate interactions and patterns of eight ecosystem services (global climate regulation, air quality regulation, erosion regulation, nutrient regulation, cyclone protection, habitat provision, energy provision, and timber provision). On average, multiple ecosystem services were highest in the rainforests, lowest in sclerophyll forests, and intermediate in rehabilitated plantation forests. However, a wide variation was apparent among the plots across the three forest types. Global climate regulation service had a synergistic impact on the supply of multiple ecosystem services, while nutrient regulation service was found to have a trade-off impact. Considering multiple ecosystem services, most of the rehabilitated plantation forest plots shared the same ordination space with rainforest plots in the ordination analysis, indicating that rehabilitated plantation forests may supply certain ecosystem services nearly equivalent to rainforests. Two synergy groups and one trade-off group were identified. Apart from conserving rainforests and sclerophyll forests, our findings suggest two additional integrated pathways to sustain the supply of multiple ecosystem services from a

  7. Ecosystem services capacity across heterogeneous forest types: understanding the interactions and suggesting pathways for sustaining multiple ecosystem services.

    PubMed

    Alamgir, Mohammed; Turton, Stephen M; Macgregor, Colin J; Pert, Petina L

    2016-10-01

    As ecosystem services supply from tropical forests is declining due to deforestation and forest degradation, much effort is essential to sustain ecosystem services supply from tropical forested landscapes, because tropical forests provide the largest flow of multiple ecosystem services among the terrestrial ecosystems. In order to sustain multiple ecosystem services, understanding ecosystem services capacity across heterogeneous forest types and identifying certain ecosystem services that could be managed to leverage positive effects across the wider bundle of ecosystem services are required. We sampled three forest types, tropical rainforests, sclerophyll forests, and rehabilitated plantation forests, over an area of 32,000m(2) from Wet Tropics bioregion, Australia, aiming to compare supply and evaluate interactions and patterns of eight ecosystem services (global climate regulation, air quality regulation, erosion regulation, nutrient regulation, cyclone protection, habitat provision, energy provision, and timber provision). On average, multiple ecosystem services were highest in the rainforests, lowest in sclerophyll forests, and intermediate in rehabilitated plantation forests. However, a wide variation was apparent among the plots across the three forest types. Global climate regulation service had a synergistic impact on the supply of multiple ecosystem services, while nutrient regulation service was found to have a trade-off impact. Considering multiple ecosystem services, most of the rehabilitated plantation forest plots shared the same ordination space with rainforest plots in the ordination analysis, indicating that rehabilitated plantation forests may supply certain ecosystem services nearly equivalent to rainforests. Two synergy groups and one trade-off group were identified. Apart from conserving rainforests and sclerophyll forests, our findings suggest two additional integrated pathways to sustain the supply of multiple ecosystem services from a

  8. Learning in Virtual Forest: A Forest Ecosystem in the Web-Based Learning Environment

    ERIC Educational Resources Information Center

    Jussila, Terttu; Virtanen, Viivi

    2014-01-01

    Virtual Forest is a web-based, open-access learning environment about forests designed for primary-school pupils between the ages of 10 and 13 years. It is pedagogically designed to develop an understanding of ecology, to enhance conceptual development and to give a holistic view of forest ecosystems. Various learning tools, such as concept maps,…

  9. Parameterisation of Biome BGC to assess forest ecosystems in Africa

    NASA Astrophysics Data System (ADS)

    Gautam, Sishir; Pietsch, Stephan A.

    2010-05-01

    African forest ecosystems are an important environmental and economic resource. Several studies show that tropical forests are critical to society as economic, environmental and societal resources. Tropical forests are carbon dense and thus play a key role in climate change mitigation. Unfortunately, the response of tropical forests to environmental change is largely unknown owing to insufficient spatially extensive observations. Developing regions like Africa where records of forest management for long periods are unavailable the process-based ecosystem simulation model - BIOME BGC could be a suitable tool to explain forest ecosystem dynamics. This ecosystem simulation model uses descriptive input parameters to establish the physiology, biochemistry, structure, and allocation patterns within vegetation functional types, or biomes. Undocumented parameters for larger-resolution simulations are currently the major limitations to regional modelling in African forest ecosystems. This study was conducted to document input parameters for BIOME-BGC for major natural tropical forests in the Congo basin. Based on available literature and field measurements updated values for turnover and mortality, allometry, carbon to nitrogen ratios, allocation of plant material to labile, cellulose, and lignin pools, tree morphology and other relevant factors were assigned. Daily climate input data for the model applications were generated using the statistical weather generator MarkSim. The forest was inventoried at various sites and soil samples of corresponding stands across Gabon were collected. Carbon and nitrogen in the collected soil samples were determined from soil analysis. The observed tree volume, soil carbon and soil nitrogen were then compared with the simulated model outputs to evaluate the model performance. Furthermore, the simulation using Congo Basin specific parameters and generalised BIOME BGC parameters for tropical evergreen broadleaved tree species were also

  10. Assessing ecosystem carbon stocks of Indonesia's threatened wetland forests

    NASA Astrophysics Data System (ADS)

    Warren, M.; Kauffman, B.; Murdiyarso, D.; Kurnianto, S.

    2011-12-01

    Over millennia, atmospheric carbon dioxide has been sequestered and stored in Indonesia's tropical wetland forests. Waterlogged conditions impede decomposition, allowing the formation of deep organic soils. These globally significant C pools are highly vulnerable to deforestation, degradation and climate change which can potentially switch their function as C sinks to long term sources of greenhouse gas (GHG) emissions. Also at risk are critical ecosystem services which sustain millions of people and the conservation of unique biological communities. The multiple benefits derived from wetland forest conservation makes them attractive for international C offset programs such as the proposed Reduced Emissions from Deforestation and Degradation (REDD+) mechanism. Yet, ecosystem C pools and fluxes in wetland forests remain poorly quantified. Significant knowledge gaps exist regarding how land use changes impact C dynamics in tropical wetlands, and very few studies have simultaneously assessed above- and belowground ecosystem C pools in Indonesia's freshwater peat swamps and mangroves. In addition, most of what is known about Indonesia's tropical wetland forests is derived from few geographic locations where long-standing research has focused, despite their broad spatial distribution. Here we present results from an extensive survey of ecosystem C stocks across several Indonesian wetland forests. Ecosystem C stocks were measured in freshwater peat swamp forests in West Papua, Central Kalimantan, West Kalimantan, and Sumatra. Carbon storage was also measured for mangrove forests in W. Papua, W. Kalimantan, and Sumatra. One overarching goal of this research is to support the development of REDD+ for tropical wetlands by informing technical issues related to carbon measuring, monitoring, and verification (MRV) and providing baseline data about the variation of ecosystem C storage across and within several Indonesian wetland forests.

  11. Drought in forest understory ecosystems - a novel rainfall reduction experiment

    NASA Astrophysics Data System (ADS)

    Gimbel, K. F.; Felsmann, K.; Baudis, M.; Puhlmann, H.; Gessler, A.; Bruelheide, H.; Kayler, Z.; Ellerbrock, R. H.; Ulrich, A.; Welk, E.; Weiler, M.

    2015-02-01

    Precipitation patterns across Central Europe are expected to change over the 21st century due to climate change. This may reduce water availability during the plant-growing season and hence affect the performance and vitality of forest ecosystems. We established a novel rainfall reduction experiment on nine sites in Germany to investigate drought effects on soil-forest-understory ecosystems. A realistic, but extreme annual drought with a return period of 40 years, which corresponds to the 2.5% percentile of the annual precipitation, was imposed. At all sites, we were able to reach the target values of rainfall reduction, while other important ecosystem variables like air temperature, humidity, and soil temperature remained unaffected due to the novel design of a flexible roof. The first year of drought showed considerable changes in the soil moisture dynamics relative to the control sites, which affected leaf stomatal conductance of understory species as well as evapotranspiration rates of the forest understory.

  12. A climate sensitive model of carbon transfer through atmosphere, vegetation and soil in managed forest ecosystems

    NASA Astrophysics Data System (ADS)

    Loustau, D.; Moreaux, V.; Bosc, A.; Trichet, P.; Kumari, J.; Rabemanantsoa, T.; Balesdent, J.; Jolivet, C.; Medlyn, B. E.; Cavaignac, S.; Nguyen-The, N.

    2012-12-01

    For predicting the future of the forest carbon cycle in forest ecosystems, it is necessary to account for both the climate and management impacts. Climate effects are significant not only at a short time scale but also at the temporal horizon of a forest life cycle e.g. through shift in atmospheric CO2 concentration, temperature and precipitation regimes induced by the enhanced greenhouse effect. Intensification of forest management concerns an increasing fraction of temperate and tropical forests and untouched forests represents only one third of the present forest area. Predicting tools are therefore needed to project climate and management impacts over the forest life cycle and understand the consequence of management on the forest ecosystem carbon cycle. This communication summarizes the structure, main components and properties of a carbon transfer model that describes the processes controlling the carbon cycle of managed forest ecosystems. The model, GO+, links three main components, (i) a module describing the vegetation-atmosphere mass and energy exchanges in 3D, (ii) a plant growth module and a (iii) soil carbon dynamics module in a consistent carbon scheme of transfer from atmosphere back into the atmosphere. It was calibrated and evaluated using observed data collected on coniferous and broadleaved forest stands. The model predicts the soil, water and energy balance of entire rotations of managed stands from the plantation to the final cut and according to a range of management alternatives. It accounts for the main soil and vegetation management operations such as soil preparation, understorey removal, thinnings and clearcutting. Including the available knowledge on the climatic sensitivity of biophysical and biogeochemical processes involved in atmospheric exchanges and carbon cycle of forest ecosystems, GO+ can produce long-term backward or forward simulations of forest carbon and water cycles under a range of climate and management scenarios. This

  13. Forest Ecosystem Dynamics Assessment and Predictive Modelling in Eastern Himalaya

    NASA Astrophysics Data System (ADS)

    Kushwaha, S. P. S.; Nandy, S.; Ahmad, M.; Agarwal, R.

    2011-09-01

    This study focused on the forest ecosystem dynamics assessment and predictive modelling deforestation and forest cover prediction in a part of north-eastern India i.e. forest areas along West Bengal, Bhutan, Arunachal Pradesh and Assam border in Eastern Himalaya using temporal satellite imagery of 1975, 1990 and 2009 and predicted forest cover for the period 2028 using Cellular Automata Markov Modedel (CAMM). The exercise highlighted large-scale deforestation in the study area during 1975-1990 as well as 1990-2009 forest cover vectors. A net loss of 2,334.28 km2 forest cover was noticed between 1975 and 2009, and with current rate of deforestation, a forest area of 4,563.34 km2 will be lost by 2028. The annual rate of deforestation worked out to be 0.35 and 0.78% during 1975-1990 and 1990-2009 respectively. Bamboo forest increased by 24.98% between 1975 and 2009 due to opening up of the forests. Forests in Kokrajhar, Barpeta, Darrang, Sonitpur, and Dhemaji districts in Assam were noticed to be worst-affected while Lower Subansiri, West and East Siang, Dibang Valley, Lohit and Changlang in Arunachal Pradesh were severely affected. Among different forest types, the maximum loss was seen in case of sal forest (37.97%) between 1975 and 2009 and is expected to deplete further to 60.39% by 2028. The tropical moist deciduous forest was the next category, which decreased from 5,208.11 km2 to 3,447.28 (33.81%) during same period with further chances of depletion to 2,288.81 km2 (56.05%) by 2028. It noted progressive loss of forests in the study area between 1975 and 2009 through 1990 and predicted that, unless checked, the area is in for further depletion of the invaluable climax forests in the region, especially sal and moist deciduous forests. The exercise demonstrated high potential of remote sensing and geographic information system for forest ecosystem dynamics assessment and the efficacy of CAMM to predict the forest cover change.

  14. Estimates of the distributions of forest ecosystem model inputs for deciduous forests of eastern North America.

    PubMed

    Radtke, P J; Burk, T E; Bolstad, P V

    2001-05-01

    Techniques for evaluating uncertainties in process-based, computer simulation models are evolving in response to the proliferation of such models and the demand for their use in the management of forest ecosystems. Many evaluation techniques require precise statements of the uncertainties associated with each model input. Statements of uncertainty are typically formulated as probability density functions (pdfs). Here, pdfs are developed for 29 inputs of the process-based, forest ecosystem, computer simulation model PnET-II, many of which are inputs to other well-known forest ecosystem models. The inputs considered describe vegetation characteristics of forests typical of the Eastern Deciduous Forest biome of North America. Data were compiled largely from published literature to estimate pdfs. The compiled distributions can be used to conduct various model evaluations including uncertainty assessment, calibration, and sensitivity analysis.

  15. Monitoring Change in Temperate Coniferous Forest Ecosystems

    NASA Technical Reports Server (NTRS)

    Williams, Darrel (Technical Monitor); Woodcock, Curtis E.

    2004-01-01

    The primary goal of this research was to improve monitoring of temperate forest change using remote sensing. In this context, change includes both clearing of forest due to effects such as fire, logging, or land conversion and forest growth and succession. The Landsat 7 ETM+ proved an extremely valuable research tool in this domain. The Landsat 7 program has generated an extremely valuable transformation in the land remote sensing community by making high quality images available for relatively low cost. In addition, the tremendous improvements in the acquisition strategy greatly improved the overall availability of remote sensing images. I believe that from an historical prespective, the Landsat 7 mission will be considered extremely important as the improved image availability will stimulate the use of multitemporal imagery at resolutions useful for local to regional mapping. Also, Landsat 7 has opened the way to global applications of remote sensing at spatial scales where important surface processes and change can be directly monitored. It has been a wonderful experience to have participated on the Landsat 7 Science Team. The research conducted under this project led to contributions in four general domains: I. Improved understanding of the information content of images as a function of spatial resolution; II. Monitoring Forest Change and Succession; III. Development and Integration of Advanced Analysis Methods; and IV. General support of the remote sensing of forests and environmental change. This report is organized according to these topics. This report does not attempt to provide the complete details of the research conducted with support from this grant. That level of detail is provided in the 16 peer reviewed journal articles, 7 book chapters and 5 conference proceedings papers published as part of this grant. This report attempts to explain how the various publications fit together to improve our understanding of how forests are changing and how to

  16. Assessing China's Forest Ecosystem Carbon Accumulation Using China's Forest Carbon Model (CFCM)

    NASA Astrophysics Data System (ADS)

    Huang, M.

    2015-12-01

    China's forests have a great potential in mitigating the rate of global climate change. Carbon sequestration capacity in China's forest ecosystems has been estimated using inventory and modeling methods in the past two decades. However, different methods result in varied magnitudes and large uncertainties exist especially in the soil carbon estimation. In this study, a model named China's forest carbon model (CFCM) has been developed based on over 7000 forest field plots data obtained during 2011-2014 to estimate China's forest ecosystem carbon sequestration capacity. The simulated forest biomass and soil carbon densities correspond well with field observations across China. Our calculation shown China's total forest biomass carbon sink decreased from 210 Tg C a-1 in 2002 to 175 Tg C a-1 in 2010, and total forest soil C sink fluctuated between -10-32Tg C a-1 during 2002-2010. Total forest soil C sink is closely correlated with interannual soil temperature change. Combine biomass and soil C sink, China's forest ecosystem C sink is in the range of 180-231 Tg C a-1, with the maximum value in 2005 and minimum in 2007 during 2001-2010.

  17. Different cesium-137 transfers to forest and stream ecosystems.

    PubMed

    Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N; Iwamoto, Aimu; Okada, Kengo

    2016-02-01

    Understanding the mechanisms of (137)Cs movement across different ecosystems is crucial for projecting the environmental impact and management of nuclear contamination events. Here, we report differential movement of (137)Cs in adjacent forest and stream ecosystems. The food webs of the forest and stream ecosystems in our study were similar, in that they were both dominated by detrital-based food webs and the basal energy source was terrestrial litter. However, the concentration of (137)Cs in stream litter was significantly lower than in forest litter, the result of (137)Cs leaching from litter in stream water. The difference in (137)Cs concentrations between the two types of litter was reflected in the (137)Cs concentrations in the animal community. While the importance of (137)Cs fallout and the associated transfer to food webs has been well studied, research has been primarily limited to cases in a single ecosystem. Our results indicate that there are differences in the flow of (137)Cs through terrestrial and aquatic ecosystems, and that (137)Cs concentrations are reduced in both basal food resources and higher trophic animals in aquatic systems, where primary production is subsidized by a neighboring terrestrial ecosystem. PMID:26629645

  18. Different cesium-137 transfers to forest and stream ecosystems.

    PubMed

    Sakai, Masaru; Gomi, Takashi; Negishi, Junjiro N; Iwamoto, Aimu; Okada, Kengo

    2016-02-01

    Understanding the mechanisms of (137)Cs movement across different ecosystems is crucial for projecting the environmental impact and management of nuclear contamination events. Here, we report differential movement of (137)Cs in adjacent forest and stream ecosystems. The food webs of the forest and stream ecosystems in our study were similar, in that they were both dominated by detrital-based food webs and the basal energy source was terrestrial litter. However, the concentration of (137)Cs in stream litter was significantly lower than in forest litter, the result of (137)Cs leaching from litter in stream water. The difference in (137)Cs concentrations between the two types of litter was reflected in the (137)Cs concentrations in the animal community. While the importance of (137)Cs fallout and the associated transfer to food webs has been well studied, research has been primarily limited to cases in a single ecosystem. Our results indicate that there are differences in the flow of (137)Cs through terrestrial and aquatic ecosystems, and that (137)Cs concentrations are reduced in both basal food resources and higher trophic animals in aquatic systems, where primary production is subsidized by a neighboring terrestrial ecosystem.

  19. An ecosystem model for tropical forest disturbance and selective logging

    NASA Astrophysics Data System (ADS)

    Huang, Maoyi; Asner, Gregory P.; Keller, Michael; Berry, Joseph A.

    2008-03-01

    A new three-dimensional version of the Carnegie-Ames-Stanford Approach (CASA) ecosystem model (CASA-3D) was developed to simulate regional carbon cycling in tropical forest ecosystems after disturbances such as logging. CASA-3D has the following new features: (1) an alternative approach for calculating absorbed photosynthetically active radiation (APAR) using new high-resolution satellite images of forest canopy gap fraction; (2) a pulse disturbance module to modify aboveground carbon pools following forest disturbance; (3) a regrowth module that simulates changes in community composition by considering gap phase regeneration; and (4) a radiative transfer module to simulate the dynamic three-dimensional light environment above the canopy and within gaps after forest disturbance. The model was calibrated with and tested against field observations from experimental logging plots in the Large-scale Biosphere Atmosphere Experiment in Amazonia (LBA) project. The sensitivity of key model parameters was evaluated using Monte Carlo simulations, and the uncertainties in simulated NPP and respiration associated with model parameters and meteorological variables were assessed. We found that selective logging causes changes in forest architecture and composition that result in a cascading set of impacts on the carbon cycling of rainforest ecosystems. Our model sensitivity and uncertainty analyses also highlight the paramount importance of measuring changes in canopy gap fraction from satellite data, as well as canopy light-use efficiency from ecophysiological measurements, to understand the role of forest disturbance on landscape and regional carbon cycling in tropical forests. In sum, our study suggests that CASA-3D may be suitable for regional-scale applications to assess the large-scale effects of selective logging, to provide guidance for forest management, and to understand the role of forest disturbance in regional and global climate studies.

  20. Bifurcation analysis of a forest-grassland ecosystem

    NASA Astrophysics Data System (ADS)

    Russo, Lucia; Spiliotis, Konstantinos G.

    2016-06-01

    The nonlinear analysis of a forest-grassland ecosystem is performed as the main system parameters are changed. The model consists of a couple of nonlinear ordinary differential equations which include dynamically the human perceptions of forest/grassland value. The system displays multiple steady states corresponding to different forest densities as well as periodic regimes characterized by oscillations in time. We performed the bifurcation analysis of the system as the parameter relative to the human opinions influence is changed. We found that the main mechanisms which regulate the transitions occurring between different states or the appearance of new steady and dynamic regimes are transcritical, saddle/node and Hopf bifurcations.

  1. Gross primary production of global forest ecosystems has been overestimated

    PubMed Central

    Ma, Jianyong; Yan, Xiaodong; Dong, Wenjie; Chou, Jieming

    2015-01-01

    Coverage rate, a critical variable for gridded forest area, has been neglected by previous studies in estimating the annual gross primary production (GPP) of global forest ecosystems. In this study, we investigated to what extent the coverage rate could impact forest GPP estimates from 1982 to 2011. Here we show that the traditional calculation without considering the coverage rate globally overestimated the forest gross carbon dioxide uptake by approximately 8.7%, with a value of 5.12 ± 0.23 Pg C yr−1, which is equivalent to 48% of the annual emissions from anthropogenic activities in 2012. Actually, the global annual GPP of forest ecosystems is approximately 53.71 ± 4.83 Pg C yr−1 for the past 30 years by taking the coverage rate into account. Accordingly, we argue that forest annual GPP calculated by previous studies has been overestimated due to the exaggerated forest area, and therefore, coverage rate may be a required factor to further quantify the global carbon cycle. PMID:26027557

  2. Sustainable carbon uptake - important ecosystem service within sustainable forest management

    NASA Astrophysics Data System (ADS)

    Zorana Ostrogović Sever, Maša; Anić, Mislav; Paladinić, Elvis; Alberti, Giorgio; Marjanović, Hrvoje

    2016-04-01

    Even-aged forest management with natural regeneration under continuous cover (i.e. close to nature management) is considered to be sustainable regarding the yield, biodiversity and stability of forest ecosystems. Recently, in the context of climate change, there is a raising question of sustainable forest management regarding carbon uptake. Aim of this research was to explore whether current close to nature forest management approach in Croatia can be considered sustainable in terms of carbon uptake throughout the life-time of Pedunculate oak forest. In state-owned managed forest a chronosequence experiment was set up and carbon stocks in main ecosystem pools (live biomass, dead wood, litter and mineral soil layer), main carbon fluxes (net primary production, soil respiration (SR), decomposition) and net ecosystem productivity were estimated in eight stands of different age (5, 13, 38, 53, 68, 108, 138 and 168 years) based on field measurements and published data. Air and soil temperature and soil moisture were recorded on 7 automatic mini-meteorological stations and weekly SR measurements were used to parameterize SR model. Carbon balance was estimated at weekly scale for the growing season 2011 (there was no harvesting), as well as throughout the normal rotation period of 140 years (harvesting was included). Carbon stocks in different ecosystem pools change during a stand development. Carbon stocks in forest floor increase with stand age, while carbon stocks in dead wood are highest in young and older stands, and lowest in middle-aged, mature stands. Carbon stocks in mineral soil layer were found to be stable across chronosequence with no statistically significant age-dependent trend. Pedunculate Oak stand, assuming successful regeneration, becomes carbon sink very early in a development phase, between the age of 5 and 13 years, and remains carbon sink even after the age of 160 years. Greatest carbon sink was reached in the stand aged 53 years. Obtained results

  3. Mechanisms of nitrogen retention in forest ecosystems - A field experiment

    NASA Technical Reports Server (NTRS)

    Vitousek, P. M.; Matson, P. A.

    1984-01-01

    Intensive forest management led to elevated losses of nitrogen from a recently harvested loblolly pine plantation in North Carolina. Measurements of nitrogen-15 retention in the field demonstrated that microbial uptake of nitrogen during the decomposition of residual organic material was the most important process retaining nitrogen. Management practices that remove this material cause increased losses of nitrogen to aquatic ecosystems and the atmosphere.

  4. Calcium constrains plant control over forest ecosystem nitrogen cycling.

    PubMed

    Groffman, Peter M; Fisk, Melany C

    2011-11-01

    Forest ecosystem nitrogen (N) cycling is a critical controller of the ability of forests to prevent the movement of reactive N to receiving waters and the atmosphere and to sequester elevated levels of atmospheric carbon dioxide (CO2). Here we show that calcium (Ca) constrains the ability of northern hardwood forest trees to control the availability and loss of nitrogen. We evaluated soil N-cycling response to Ca additions in the presence and absence of plants and observed that when plants were present, Ca additions "tightened" the ecosystem N cycle, with decreases in inorganic N levels, potential net N mineralization rates, microbial biomass N content, and denitrification potential. In the absence of plants, Ca additions induced marked increases in nitrification (the key process controlling ecosystem N losses) and inorganic N levels. The observed "tightening" of the N cycle when Ca was added in the presence of plants suggests that the capacity of forests to absorb elevated levels of atmospheric N and CO2 is fundamentally constrained by base cations, which have been depleted in many areas of the globe by acid rain and forest harvesting.

  5. Urban Forest Ecosystem Service Optimization, Tradeoffs, and Disparities

    NASA Astrophysics Data System (ADS)

    Bodnaruk, E.; Kroll, C. N.; Endreny, T. A.; Hirabayashi, S.; Yang, Y.

    2014-12-01

    Urban land area and the proportion of humanity living in cities is growing, leading to increased urban air pollution, temperature, and stormwater runoff. These changes can exacerbate respiratory and heat-related illnesses and affect ecosystem functioning. Urban trees can help mitigate these threats by removing air pollutants, mitigating urban heat island effects, and infiltrating and filtering stormwater. The urban environment is highly heterogeneous, and there is no tool to determine optimal locations to plant or protect trees. Using spatially explicit land cover, weather, and demographic data within biophysical ecosystem service models, this research expands upon the iTree urban forest tools to produce a new decision support tool (iTree-DST) that will explore the development and impacts of optimal tree planting. It will also heighten awareness of environmental justice by incorporating the Atkinson Index to quantify disparities in health risks and ecosystem services across vulnerable and susceptible populations. The study area is Baltimore City, a location whose urban forest and environmental justice concerns have been studied extensively. The iTree-DST is run at the US Census block group level and utilizes a local gradient approach to calculate the change in ecosystem services with changing tree cover across the study area. Empirical fits provide ecosystem service gradients for possible tree cover scenarios, greatly increasing the speed and efficiency of the optimization procedure. Initial results include an evaluation of the performance of the gradient method, optimal planting schemes for individual ecosystem services, and an analysis of tradeoffs and synergies between competing objectives.

  6. Potential climate change impacts on temperate forest ecosystem processes

    USGS Publications Warehouse

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

    2013-01-01

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

  7. Characterizing forest ecosystem dynamics through modelling and remote sensing observations

    NASA Technical Reports Server (NTRS)

    Ranson, K. J.; Smith, J. A.; Hall, F. G.

    1988-01-01

    To gain a better understanding of northern/boreal forest dynamics over a range of spatial and temporal scales, an approach to integrate models of forest growth, soil processes and radiative transfer with remote sensing observations was developed. The integrated model and remote sensing can be used to examine descriptors of ecosystem dynamics. To examine the scaling of vegetation pattern from the local to the regional domain, distributions of area and perimeters of vegetation community associations were determined from satellite and aircraft images. Relationships between computed fractal dimensions (1.5 to 1.8) and succession history for managed and unmanaged areas are being explored.

  8. Estimating key forest ecosystem parameters through remote sensing

    NASA Technical Reports Server (NTRS)

    Wessman, Carol A.; Aber, John D.; Peterson, David L.

    1987-01-01

    Forest canopy chemistry and biomass indicators of ecosystem photosynthesis and decomposition processes are presently studied in view of Airborne Imaging Spectrometer data, which generated spectra from averaged 3 x 3 pixel areas for each of 20 sites for mutual qualitative comparison. Vegetation spectra were strongly differentiated from other cover types by an apparent absorption feature at 1500-1700 nm. Preliminary work with stepwise regression suggests that lignin may play a role in canopy reflectance, and that there is potential for remote detection of forest canopy lignin.

  9. ESRP approach to using final ecosystem services

    EPA Science Inventory

    The U.S. Environmental Protection Agency has developed the ecosystem Services Research Program (ESRP) as one of its major research efforts. The goal of this program is to create “A comprehensive theory and practice for quantifying ecosystem services so that their value and their...

  10. Spatial and temporal patterns of carbon storage in forest ecosystems on Hainan island, southern China.

    PubMed

    Ren, Hai; Li, Linjun; Liu, Qiang; Wang, Xu; Li, Yide; Hui, Dafeng; Jian, Shuguang; Wang, Jun; Yang, Huai; Lu, Hongfang; Zhou, Guoyi; Tang, Xuli; Zhang, Qianmei; Wang, Dong; Yuan, Lianlian; Chen, Xubing

    2014-01-01

    Spatial and temporal patterns of carbon (C) storage in forest ecosystems significantly affect the terrestrial C budget, but such patterns are unclear in the forests in Hainan Province, the largest tropical island in China. Here, we estimated the spatial and temporal patterns of C storage from 1993-2008 in Hainan's forest ecosystems by combining our measured data with four consecutive national forest inventories data. Forest coverage increased from 20.7% in the 1950s to 56.4% in the 2010s. The average C density of 163.7 Mg C/ha in Hainan's forest ecosystems in this study was slightly higher than that of China's mainland forests, but was remarkably lower than that in the tropical forests worldwide. Total forest ecosystem C storage in Hainan increased from 109.51 Tg in 1993 to 279.17 Tg in 2008. Soil C accounted for more than 70% of total forest ecosystem C. The spatial distribution of forest C storage in Hainan was uneven, reflecting differences in land use change and forest management. The potential carbon sequestration of forest ecosystems was 77.3 Tg C if all forested lands were restored to natural tropical forests. To increase the C sequestration potential on Hainan Island, future forest management should focus on the conservation of natural forests, selection of tree species, planting of understory species, and implementation of sustainable practices.

  11. Spatial and Temporal Patterns of Carbon Storage in Forest Ecosystems on Hainan Island, Southern China

    PubMed Central

    Tang, Xuli; Zhang, Qianmei; Wang, Dong; Yuan, Lianlian; Chen, Xubing

    2014-01-01

    Spatial and temporal patterns of carbon (C) storage in forest ecosystems significantly affect the terrestrial C budget, but such patterns are unclear in the forests in Hainan Province, the largest tropical island in China. Here, we estimated the spatial and temporal patterns of C storage from 1993–2008 in Hainan's forest ecosystems by combining our measured data with four consecutive national forest inventories data. Forest coverage increased from 20.7% in the 1950s to 56.4% in the 2010s. The average C density of 163.7 Mg C/ha in Hainan's forest ecosystems in this study was slightly higher than that of China's mainland forests, but was remarkably lower than that in the tropical forests worldwide. Total forest ecosystem C storage in Hainan increased from 109.51 Tg in 1993 to 279.17 Tg in 2008. Soil C accounted for more than 70% of total forest ecosystem C. The spatial distribution of forest C storage in Hainan was uneven, reflecting differences in land use change and forest management. The potential carbon sequestration of forest ecosystems was 77.3 Tg C if all forested lands were restored to natural tropical forests. To increase the C sequestration potential on Hainan Island, future forest management should focus on the conservation of natural forests, selection of tree species, planting of understory species, and implementation of sustainable practices. PMID:25229628

  12. Study of the radiocesium dynamics in the Fukushima forest ecosystems

    NASA Astrophysics Data System (ADS)

    Yoschenko, Vasyl; Konoplev, Alexei; Takase, Tsugiko; Nanba, Kenji; Onda, Yuichi; Zheleznyak, Mark; Kivva, Sergii

    2016-04-01

    Accident at Fukushima Dai-ichi NPP on March 11, 2011, has resulted in release into the environment of large amounts of radiocesium (134Cs and 137Cs) and in radioactive contamination of terrestrial and aquatic ecosystems. Up to 2/3 of the most contaminated territory in Fukushima prefecture is covered with forests, and efforts aimed at revitalization of this territory should include, therefore, elaboration of the forestry strategy. In particular, understanding of the radiocesium dynamics in the ecosystem compartments is necessary for the reliable long-term prognosis. Numerous studies revealed and quantified the key processes governing radiocesium redistribution in Fukushima forests at the early stage after the accident, when initially intercepted radiocesium was gradually transported from the trees' crowns to the soil surface and profile with precipitations and litterfall, and the general trend was a decrease of the radiocesium total inventory in the forest biomass. However, at the later stage, the radiocesium activities in the biomass compartments can increase due to its root uptake from the soil profile; the two major processes, radionuclide root uptake and its return to soil, will determine the future radiocesium levels in the forest compartments. Objectives of our study were characterization of the radiocesium distribution at the beginning of the late stage, revealing its dynamics and parameterization of the above-mentioned fluxes for prognosis of the radiocesium long-term redistribution in the typical Fukushima forest ecosystems. The study started at one experimental site (Yamakiya district, Kawamata town, Fukushima Prefecture) in the spring of 2014; to the moment, it has been continuing at several experimental sites in the Fukushima zone characterized by different species composition and soil-landscape conditions. For the typical Japanese cedar (Cryptomeria japonica) and Japanese red pine (Pinus Densiflora) forests, we determined distributions of radiocesium in

  13. Forest Ecosystem Processes at the Watershed Scale: Ecosystem services, feedback and evolution in developing mountainous catchments

    NASA Astrophysics Data System (ADS)

    Band, Larry

    2010-05-01

    Mountain watersheds provide significant ecosystem services both locally and for surrounding regions, including the provision of freshwater, hydropower, carbon sequestration, habitat, forest products and recreational/aesthetic opportunities. The hydrologic connectivity along hillslopes in sloping terrain provides an upslope subsidy of water and nutrients to downslope ecosystem patches, producing characteristic ecosystem patterns of vegetation density and type, and soil biogeochemical cycling. Recent work suggests that optimal patterns of forest cover evolve along these flowpaths which maximize net primary productivity and carbon sequestration at the hillslope to catchment scale. These watersheds are under significant pressure from potential climate change, changes in forest management, increasing population and development, and increasing demand for water export. As water balance and flowpaths are altered by shifting weather patterns and new development, the spatial distribution and coupling of water, carbon and nutrient cycling will spur the evolution of different ecosystem patterns. These issues have both theoretical and practical implications for the coupling of water, carbon and nutrient cycling at the landscape level, and the potential to manage watersheds for bundled ecosystem services. If the spatial structure of the ecosystem spontaneously adjusts to maximize landscape level use of limiting resources, there may be trade-offs in the level of services provided. The well known carbon-for-water tradeoff reflects the growth of forests to maximize carbon uptake, but also transpiration which limits freshwater availability in many biomes. We provide examples of the response of bundled ecosystem services to climate and land use change in the Southern Appalachian Mountains of the United States. These mountains have very high net primary productivity, biodiversity and water yields, and provide significant freshwater resources to surrounding regions. There has been a

  14. Climate change impact on peatland and forest ecosystems of Russia

    SciTech Connect

    Kondrasheva, N.Yu.; Kobak, K.I.; Turchinovich, I.Ye.

    1996-12-31

    Paleoclimatic and paleobotanic reconstructions allow a conclusion that ecosystems and natural zones significantly changed due to climate fluctuations. The average long-term carbon accumulation in peatlands of Russia was estimated as 45.6 mln tons of carbon per year. During the Holocene the rate of peat accumulation changed. During the Subboreal period the rate of peat accumulation gradually decreased to 17 gC/m2 yr, reaching its lowest value in the Subatlantic period. Apparently, the rate of peat accumulation decreased in Subboreal period due to sharp cooling and precipitation decrease. Future rates of peat accumulation might be higher than the present one. Forest ecosystems of north-western Russia also significantly changed during the Holocene. In Atlantic time the boundary between middle and south taiga was located 500 km northward compared to the present and broad-leaved forest occupied large areas. According to their forecast, a mean global air temperature increase by 1.4 C is expected to result in a considerable decrease in coniferous forest area and an increase in mixed and broad-leaved forest area.

  15. Vulnerability of tropical forest ecosystems and forest dependent communities to droughts.

    PubMed

    Vogt, D J; Vogt, K A; Gmur, S J; Scullion, J J; Suntana, A S; Daryanto, S; Sigurðardóttir, R

    2016-01-01

    Energy captured by and flowing through a forest ecosystem can be indexed by its total Net Primary Productivity (NPP). This forest NPP can also be a reflection of its sensitivity to, and its ability to adapt to, any climate change while also being harvested by humans. However detecting and identifying the vulnerability of forest and human ecosystems to climate change requires information on whether these coupled social and ecological systems are able to maintain functionality while responding to environmental variability. To better understand what parameters might be representative of environmental variability, we compiled a metadata analysis of 96 tropical forest sites. We found that three soil textural classes (i.e., sand, sandy loam and clay) had significant but different relationships between NPP and precipitation levels. Therefore, assessing the vulnerability of forests and forest dependent communities to drought was carried out using data from those sites that had one of those three soil textural classes. For example, forests growing on soil textures of sand and clay had NPP levels decreasing as precipitation levels increased, in contrast to those forest sites that had sandy loam soils where NPP levels increased. Also, forests growing on sandy loam soil textures appeared better adapted to grow at lower precipitation levels compared to the sand and clay textured soils. In fact in our tropical database the lowest precipitation level found for the sandy loam soils was 821 mm yr(-1) compared to sand at 1739 mm yr(-1) and clay at 1771 mm yr(-1). Soil texture also determined the level of NPP reached by a forest, i.e., forest growing on sandy loam and clay reached low-medium NPP levels while higher NPP levels (i.e., medium, high) were found on sand-textured soils. Intermediate precipitation levels (>1800-3000 mm yr(-1)) were needed to grow forests at the medium and high NPP levels. Low thresholds of NPP were identified at both low (∼750 mm) and high precipitation

  16. Vulnerability of tropical forest ecosystems and forest dependent communities to droughts.

    PubMed

    Vogt, D J; Vogt, K A; Gmur, S J; Scullion, J J; Suntana, A S; Daryanto, S; Sigurðardóttir, R

    2016-01-01

    Energy captured by and flowing through a forest ecosystem can be indexed by its total Net Primary Productivity (NPP). This forest NPP can also be a reflection of its sensitivity to, and its ability to adapt to, any climate change while also being harvested by humans. However detecting and identifying the vulnerability of forest and human ecosystems to climate change requires information on whether these coupled social and ecological systems are able to maintain functionality while responding to environmental variability. To better understand what parameters might be representative of environmental variability, we compiled a metadata analysis of 96 tropical forest sites. We found that three soil textural classes (i.e., sand, sandy loam and clay) had significant but different relationships between NPP and precipitation levels. Therefore, assessing the vulnerability of forests and forest dependent communities to drought was carried out using data from those sites that had one of those three soil textural classes. For example, forests growing on soil textures of sand and clay had NPP levels decreasing as precipitation levels increased, in contrast to those forest sites that had sandy loam soils where NPP levels increased. Also, forests growing on sandy loam soil textures appeared better adapted to grow at lower precipitation levels compared to the sand and clay textured soils. In fact in our tropical database the lowest precipitation level found for the sandy loam soils was 821 mm yr(-1) compared to sand at 1739 mm yr(-1) and clay at 1771 mm yr(-1). Soil texture also determined the level of NPP reached by a forest, i.e., forest growing on sandy loam and clay reached low-medium NPP levels while higher NPP levels (i.e., medium, high) were found on sand-textured soils. Intermediate precipitation levels (>1800-3000 mm yr(-1)) were needed to grow forests at the medium and high NPP levels. Low thresholds of NPP were identified at both low (∼750 mm) and high precipitation

  17. Ecosystem-Level Carbon Stocks in Costa Rican Mangrove Forests

    NASA Astrophysics Data System (ADS)

    Cifuentes, M.

    2012-12-01

    Tropical mangroves provide a wide variety of ecosystem services, including atmospheric carbon sequestration. Because of their high rates of carbon accumulation, the large expected size of their total stocks (from 2 to 5 times greater than those of upland tropical forests), and the alarming rates at which they are being converted to other uses (releasing globally from 0.02 to 0.12 Pg C yr-1), mangroves are receiving increasing attention as additional tools to mitigate climate change. However, data on whole ecosystem-level carbon in tropical mangroves is limited. Here I present the first estimate of ecosystem level carbon stocks in mangrove forests of Central America. I established 28, 125 m-long, sampling transects along the 4 main rivers draining the Térraba-Sierpe National Wetland in the southern Pacific coast of Costa Rica. This area represents 39% of all remaining mangroves in the country (48300 ha). A circular nested plot was placed every 25 m along each transect. Carbon stocks of standing trees, regeneration, the herbaceous layer, litter, and downed wood were measured following internationally-developed methods compatible with IPCC "Good Practice Guidelines". In addition, total soil carbon stocks were determined down to 1 m depth. Together, these carbon estimates represent the ecosystem-carbon stocks of these forests. The average aboveground carbon stocks were 72.5 ± 3.2 MgC ha-1 (range: 9 - 241 MgC ha-1), consistent with results elsewhere in the world. Between 74 and 92% of the aboveground carbon is stored in trees ≥ 5cm dbh. I found a significant correlation between basal area of trees ≥ 5cm dbh and total aboveground carbon. Soil carbon stocks to 1 m depth ranged between 141 y 593 MgC ha-1. Ecosystem-level carbon stocks ranged from 391 MgC ha-1 to 438 MgC ha-1, with a slight increase from south to north locations. Soil carbon stocks represent an average 76% of total ecosystem carbon stocks, while trees represent only 20%. These Costa Rican mangroves

  18. Petroleum hydrocarbon contamination in boreal forest soils: a mycorrhizal ecosystems perspective.

    PubMed

    Robertson, Susan J; McGill, William B; Massicotte, Hugues B; Rutherford, P Michael

    2007-05-01

    The importance of developing multi-disciplinary approaches to solving problems relating to anthropogenic pollution is now clearly appreciated by the scientific community, and this is especially evident in boreal ecosystems exposed to escalating threats of petroleum hydrocarbon (PHC) contamination through expanded natural resource extraction activities. This review aims to synthesize information regarding the fate and behaviour of PHCs in boreal forest soils in both ecological and sustainable management contexts. From this, we hope to evaluate potential management strategies, identify gaps in knowledge and guide future research. Our central premise is that mycorrhizal systems, the ubiquitous root symbiotic fungi and associated food-web communities, occupy the structural and functional interface between decomposition and primary production in northern forest ecosystems (i.e. underpin survival and productivity of the ecosystem as a whole), and, as such, are an appropriate focal point for such a synthesis. We provide pertinent basic information about mycorrhizas, followed by insights into the ecology of ecto- and ericoid mycorrhizal systems. Next, we review the fate and behaviour of PHCs in forest soils, with an emphasis on interactions with mycorrhizal fungi and associated bacteria. Finally, we summarize implications for ecosystem management. Although we have gained tremendous insights into understanding linkages between ecosystem functions and the various aspects of mycorrhizal diversity, very little is known regarding rhizosphere communities in PHC-contaminated soils. This makes it difficult to translate ecological knowledge into environmental management strategies. Further research is required to determine which fungal symbionts are likely to survive and compete in various ecosystems, whether certain fungal - plant associations gain in ecological importance following contamination events, and how PHC contamination may interfere with processes of nutrient

  19. Soil and water related forest ecosystem services and resilience of social ecological system in the Central Highlands of Ethiopia

    NASA Astrophysics Data System (ADS)

    Tekalign, Meron; Muys, Bart; Nyssen, Jan; Poesen, Jean

    2014-05-01

    In the central highlands of Ethiopia, deforestation and forest degradation are occurring and accelerating during the last century. The high population pressure is the most repeatedly mentioned reason. However, in the past 30 years researchers agreed that the absence of institutions, which could define the access rights to particular forest resources, is another underlying cause of forest depletion and loss. Changing forest areas into different land use types is affecting the biodiversity, which is manifested through not proper functioning of ecosystem services. Menagesha Suba forest, the focus of this study has been explored from various perspectives. However the social dimension and its interaction with the ecology have been addressed rarely. This research uses a combined theoretical framework of Ecosystem Services and that of Resilience thinking for understanding the complex social-ecological interactions in the forest and its influence on ecosystem services. For understanding the history and extent of land use land cover changes, in-depth literature review and a GIS and remote sensing analysis will be made. The effect of forest conversion into plantation and agricultural lands on soil and above ground carbon sequestration, fuel wood and timber products delivery will be analyzed with the accounting of the services on five land use types. The four ecosystem services to be considered are Supporting, Provisioning, Regulating, and Cultural services as set by the Millennium Ecosystem Assessment. A resilience based participatory framework approach will be used to analyze how the social and ecological systems responded towards the drivers of change that occurred in the past. The framework also will be applied to predict future uncertainties. Finally this study will focus on the possible interventions that could contribute to the sustainable management and conservation of the forest. An ecosystem services trade-off analysis and an environmental valuation of the water

  20. Models for Forest Ecosystem Management: A European Perspective

    PubMed Central

    Pretzsch, H.; Grote, R.; Reineking, B.; Rötzer, Th.; Seifert, St.

    2008-01-01

    Background Forest management in Europe is committed to sustainability. In the face of climate change and accompanying risks, however, planning in order to achieve this aim becomes increasingly challenging, underlining the need for new and innovative methods. Models potentially integrate a wide range of system knowledge and present scenarios of variables important for any management decision. In the past, however, model development has mainly focused on specific purposes whereas today we are increasingly aware of the need for the whole range of information that can be provided by models. It is therefore assumed helpful to review the various approaches that are available for specific tasks and to discuss how they can be used for future management strategies. Scope Here we develop a concept for the role of models in forest ecosystem management based on historical analyses. Five paradigms of forest management are identified: (1) multiple uses, (2) dominant use, (3) environmentally sensitive multiple uses, (4) full ecosystem approach and (5) eco-regional perspective. An overview of model approaches is given that is dedicated to this purpose and to developments of different kinds of approaches. It is discussed how these models can contribute to goal setting, decision support and development of guidelines for forestry operations. Furthermore, it is shown how scenario analysis, including stand and landscape visualization, can be used to depict alternatives, make long-term consequences of different options transparent, and ease participation of different stakeholder groups and education. Conclusions In our opinion, the current challenge of forest ecosystem management in Europe is to integrate system knowledge from different temporal and spatial scales and from various disciplines. For this purpose, using a set of models with different focus that can be selected from a kind of toolbox according to particular needs is more promising than developing one overarching model

  1. A review of malaria transmission dynamics in forest ecosystems.

    PubMed

    Kar, Narayani Prasad; Kumar, Ashwani; Singh, Om P; Carlton, Jane M; Nanda, Nutan

    2014-06-09

    Malaria continues to be a major health problem in more than 100 endemic countries located primarily in tropical and sub-tropical regions around the world. Malaria transmission is a dynamic process and involves many interlinked factors, from uncontrollable natural environmental conditions to man-made disturbances to nature. Almost half of the population at risk of malaria lives in forest areas. Forests are hot beds of malaria transmission as they provide conditions such as vegetation cover, temperature, rainfall and humidity conditions that are conducive to distribution and survival of malaria vectors. Forests often lack infrastructure and harbor tribes with distinct genetic traits, socio-cultural beliefs and practices that greatly influence malaria transmission dynamics. Here we summarize the various topographical, entomological, parasitological, human ecological and socio-economic factors, which are crucial and shape malaria transmission in forested areas. An in-depth understanding and synthesis of the intricate relationship of these parameters in achieving better malaria control in various types of forest ecosystems is emphasized.

  2. A review of malaria transmission dynamics in forest ecosystems

    PubMed Central

    2014-01-01

    Malaria continues to be a major health problem in more than 100 endemic countries located primarily in tropical and sub-tropical regions around the world. Malaria transmission is a dynamic process and involves many interlinked factors, from uncontrollable natural environmental conditions to man-made disturbances to nature. Almost half of the population at risk of malaria lives in forest areas. Forests are hot beds of malaria transmission as they provide conditions such as vegetation cover, temperature, rainfall and humidity conditions that are conducive to distribution and survival of malaria vectors. Forests often lack infrastructure and harbor tribes with distinct genetic traits, socio-cultural beliefs and practices that greatly influence malaria transmission dynamics. Here we summarize the various topographical, entomological, parasitological, human ecological and socio-economic factors, which are crucial and shape malaria transmission in forested areas. An in-depth understanding and synthesis of the intricate relationship of these parameters in achieving better malaria control in various types of forest ecosystems is emphasized. PMID:24912923

  3. Spatial and temporal trends of drought effects in a heterogeneous semi-arid forest ecosystem

    USGS Publications Warehouse

    Assal, Timothy J.; Anderson, Patrick J.; Sibold, Jason

    2016-01-01

    Drought has long been recognized as a driving mechanism in the forests of western North America and drought-induced mortality has been documented across genera in recent years. Given the frequency of these events are expected to increase in the future, understanding patterns of mortality and plant response to severe drought is important to resource managers. Drought can affect the functional, physiological, structural, and demographic properties of forest ecosystems. Remote sensing studies have documented changes in forest properties due to direct and indirect effects of drought; however, few studies have addressed this at local scales needed to characterize highly heterogeneous ecosystems in the forest-shrubland ecotone. We analyzed a 22-year Landsat time series (1985–2012) to determine changes in forest in an area that experienced a relatively dry decade punctuated by two years of extreme drought. We assessed the relationship between several vegetation indices and field measured characteristics (e.g. plant area index and canopy gap fraction) and applied these indices to trend analysis to uncover the location, direction and timing of change. Finally, we assessed the interaction of climate and topography by forest functional type. The Normalized Difference Moisture Index (NDMI), a measure of canopy water content, had the strongest correlation with short-term field measures of plant area index (R2 = 0.64) and canopy gap fraction (R2 = 0.65). Over the entire time period, 25% of the forested area experienced a significant (p-value < 0.05) negative trend in NDMI, compared to less than 10% in a positive trend. Coniferous forests were more likely to be associated with a negative NDMI trend than deciduous forest. Forests on southern aspects were least likely to exhibit a negative trend while north aspects were most prevalent. Field plots with a negative trend had a lower live density, and higher amounts of standing dead and down trees compared to plots with no

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  5. (Lichens as a bioindicator in the forest ecosystem)

    SciTech Connect

    Sigal, L.L.

    1989-09-06

    Prior to a field trip of Estonia, an introductory meeting was held at the Tallinn Botanical Garden. Overviews of existing forest air pollution research in the eastern United States and Estonia were presented by American and Soviet scientists. Subsequently, potential forest monitoring sites were visited at (1) the Kurtna Landscape Sanctuary and the Pikasilla Forest near Kohtla-Jaerve, (2) the Tipu-Kopu Forest near Viljandi, and (3) a site on the western part of the island of Saaremaa. The next part of the trip was to Georgia where we met with the Director and staff of the Institute of Mountain Forestry in Tbilisi. The goals of the exchange program were explained, and the local forest management practices were discussed. A field trip was taken to the spruce-fir forests of Borzhomi. The final part of the trip was to the Central Republic of Botanical Gardens at Kiev where a preliminary experiment on the uptake of organic gases by lichens was done, a manuscript on a retrospective study of element content in lichens from the Great Smoky Mountains National Park was completed, and a seminar was given on the effects of air pollutants on forest vegetation. The seminar included an overview of air pollution facilities at Oak Ridge National Laboratory (ORNL), field study methods for determining the effects of air pollutants on lichens, and a description of techniques used to determine the effects of air pollutants on the intracellular constituents of loblolly pine protoplasts.

  6. The allocation of ecosystem net primary productivity in tropical forests

    PubMed Central

    Malhi, Yadvinder; Doughty, Christopher; Galbraith, David

    2011-01-01

    The allocation of the net primary productivity (NPP) of an ecosystem between canopy, woody tissue and fine roots is an important descriptor of the functioning of that ecosystem, and an important feature to correctly represent in terrestrial ecosystem models. Here, we collate and analyse a global dataset of NPP allocation in tropical forests, and compare this with the representation of NPP allocation in 13 terrestrial ecosystem models. On average, the data suggest an equal partitioning of allocation between all three main components (mean 34 ± 6% canopy, 39 ± 10% wood, 27 ± 11% fine roots), but there is substantial site-to-site variation in allocation to woody tissue versus allocation to fine roots. Allocation to canopy (leaves, flowers and fruit) shows much less variance. The mean allocation of the ecosystem models is close to the mean of the data, but the spread is much greater, with several models reporting allocation partitioning outside of the spread of the data. Where all main components of NPP cannot be measured, litterfall is a good predictor of overall NPP (r2 = 0.83 for linear fit forced through origin), stem growth is a moderate predictor and fine root production a poor predictor. Across sites the major component of variation of allocation is a shifting allocation between wood and fine roots, with allocation to the canopy being a relatively invariant component of total NPP. This suggests the dominant allocation trade-off is a ‘fine root versus wood’ trade-off, as opposed to the expected ‘root–shoot’ trade-off; such a trade-off has recently been posited on theoretical grounds for old-growth forest stands. We conclude by discussing the systematic biases in estimates of allocation introduced by missing NPP components, including herbivory, large leaf litter and root exudates production. These biases have a moderate effect on overall carbon allocation estimates, but are smaller than the observed range in allocation values across sites. PMID

  7. Advances of air pollution science: from forest decline to multiple-stress effects on forest ecosystem services.

    PubMed

    Paoletti, E; Schaub, M; Matyssek, R; Wieser, G; Augustaitis, A; Bastrup-Birk, A M; Bytnerowicz, A; Günthardt-Goerg, M S; Müller-Starck, G; Serengil, Y

    2010-06-01

    Over the past 20 years, the focus of forest science on air pollution has moved from forest decline to a holistic framework of forest health, and from the effects on forest production to the ecosystem services provided by forest ecosystems. Hence, future research should focus on the interacting factorial impacts and resulting antagonistic and synergistic responses of forest trees and ecosystems. The synergistic effects of air pollution and climatic changes, in particular elevated ozone, altered nitrogen, carbon and water availability, must be key issues for research. Present evidence suggests air pollution will become increasingly harmful to forests under climate change, which requires integration amongst various stressors (abiotic and biotic factors, including competition, parasites and fire), effects on forest services (production, biodiversity protection, soil protection, sustained water balance, socio-economical relevance) and assessment approaches (research, monitoring, modeling) to be fostered.

  8. Advances of air pollution science: from forest decline to multiple-stress effects on forest ecosystem services.

    PubMed

    Paoletti, E; Schaub, M; Matyssek, R; Wieser, G; Augustaitis, A; Bastrup-Birk, A M; Bytnerowicz, A; Günthardt-Goerg, M S; Müller-Starck, G; Serengil, Y

    2010-06-01

    Over the past 20 years, the focus of forest science on air pollution has moved from forest decline to a holistic framework of forest health, and from the effects on forest production to the ecosystem services provided by forest ecosystems. Hence, future research should focus on the interacting factorial impacts and resulting antagonistic and synergistic responses of forest trees and ecosystems. The synergistic effects of air pollution and climatic changes, in particular elevated ozone, altered nitrogen, carbon and water availability, must be key issues for research. Present evidence suggests air pollution will become increasingly harmful to forests under climate change, which requires integration amongst various stressors (abiotic and biotic factors, including competition, parasites and fire), effects on forest services (production, biodiversity protection, soil protection, sustained water balance, socio-economical relevance) and assessment approaches (research, monitoring, modeling) to be fostered. PMID:20036449

  9. Carbon Budget and its Dynamics over Northern Eurasia Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Shvidenko, Anatoly; Schepaschenko, Dmitry; Kraxner, Florian; Maksyutov, Shamil

    2016-04-01

    The presentation contains an overview of recent findings and results of assessment of carbon cycling of forest ecosystems of Northern Eurasia. From a methodological point of view, there is a clear tendency in understanding a need of a Full and Verified Carbon Account (FCA), i.e. in reliable assessment of uncertainties for all modules and all stages of FCA. FCA is considered as a fuzzy (underspecified) system that supposes a system integration of major methods of carbon cycling study (land-ecosystem approach, LEA; process-based models; eddy covariance; and inverse modelling). Landscape-ecosystem approach 1) serves for accumulation of all relevant knowledge of landscape and ecosystems; 2) for strict systems designing the account, 3) contains all relevant spatially distributed empirical and semi-empirical data and models, and 4) is presented in form of an Integrated Land Information System (ILIS). The ILIS includes a hybrid land cover in a spatially and temporarily explicit way and corresponding attributive databases. The forest mask is provided by utilizing multi-sensor remote sensing data, geographically weighed regression and validation within GEO-wiki platform. By-pixel parametrization of forest cover is based on a special optimization algorithms using all available knowledge and information sources (data of forest inventory and different surveys, observations in situ, official statistics of forest management etc.). Major carbon fluxes within the LEA (NPP, HR, disturbances etc.) are estimated based on fusion of empirical data and aggregations with process-based elements by sets of regionally distributed models. Uncertainties within LEA are assessed for each module and at each step of the account. Within method results of LEA and corresponding uncertainties are harmonized and mutually constrained with independent outputs received by other methods based on the Bayesian approach. The above methodology have been applied to carbon account of Russian forests for 2000

  10. A large-scale forest fragmentation experiment: the Stability of Altered Forest Ecosystems Project

    PubMed Central

    Ewers, Robert M.; Didham, Raphael K.; Fahrig, Lenore; Ferraz, Gonçalo; Hector, Andy; Holt, Robert D.; Kapos, Valerie; Reynolds, Glen; Sinun, Waidi; Snaddon, Jake L.; Turner, Edgar C.

    2011-01-01

    Opportunities to conduct large-scale field experiments are rare, but provide a unique opportunity to reveal the complex processes that operate within natural ecosystems. Here, we review the design of existing, large-scale forest fragmentation experiments. Based on this review, we develop a design for the Stability of Altered Forest Ecosystems (SAFE) Project, a new forest fragmentation experiment to be located in the lowland tropical forests of Borneo (Sabah, Malaysia). The SAFE Project represents an advance on existing experiments in that it: (i) allows discrimination of the effects of landscape-level forest cover from patch-level processes; (ii) is designed to facilitate the unification of a wide range of data types on ecological patterns and processes that operate over a wide range of spatial scales; (iii) has greater replication than existing experiments; (iv) incorporates an experimental manipulation of riparian corridors; and (v) embeds the experimentally fragmented landscape within a wider gradient of land-use intensity than do existing projects. The SAFE Project represents an opportunity for ecologists across disciplines to participate in a large initiative designed to generate a broad understanding of the ecological impacts of tropical forest modification. PMID:22006969

  11. Dynamics of Ecosystem Services during Forest Transitions in Reventazón, Costa Rica.

    PubMed

    Vallet, Améline; Locatelli, Bruno; Levrel, Harold; Brenes Pérez, Christian; Imbach, Pablo; Estrada Carmona, Natalia; Manlay, Raphaël; Oszwald, Johan

    2016-01-01

    The forest transition framework describes the temporal changes of forest areas with economic development. A first phase of forest contraction is followed by a second phase of expansion once a turning point is reached. This framework does not differentiate forest types or ecosystem services, and describes forests regardless of their contribution to human well-being. For several decades, deforestation in many tropical regions has degraded ecosystem services, such as watershed regulation, while increasing provisioning services from agriculture, for example, food. Forest transitions and expansion have been observed in some countries, but their consequences for ecosystem services are often unclear. We analyzed the implications of forest cover change on ecosystem services in Costa Rica, where a forest transition has been suggested. A review of literature and secondary data on forest and ecosystem services in Costa Rica indicated that forest transition might have led to an ecosystem services transition. We modeled and mapped the changes of selected ecosystem services in the upper part of the Reventazón watershed and analyzed how supply changed over time in order to identify possible transitions in ecosystem services. The modeled changes of ecosystem services is similar to the second phase of a forest transition but no turning point was identified, probably because of the limited temporal scope of the analysis. Trends of provisioning and regulating services and their tradeoffs were opposite in different spatial subunits of our study area, which highlights the importance of scale in the analysis of ecosystem services and forest transitions. The ecosystem services transition framework proposed in this study is useful for analyzing the temporal changes of ecosystem services and linking socio-economic drivers to ecosystem services demand at different scales.

  12. Dynamics of Ecosystem Services during Forest Transitions in Reventazón, Costa Rica

    PubMed Central

    Vallet, Améline; Locatelli, Bruno; Levrel, Harold; Brenes Pérez, Christian; Imbach, Pablo; Estrada Carmona, Natalia; Manlay, Raphaël; Oszwald, Johan

    2016-01-01

    The forest transition framework describes the temporal changes of forest areas with economic development. A first phase of forest contraction is followed by a second phase of expansion once a turning point is reached. This framework does not differentiate forest types or ecosystem services, and describes forests regardless of their contribution to human well-being. For several decades, deforestation in many tropical regions has degraded ecosystem services, such as watershed regulation, while increasing provisioning services from agriculture, for example, food. Forest transitions and expansion have been observed in some countries, but their consequences for ecosystem services are often unclear. We analyzed the implications of forest cover change on ecosystem services in Costa Rica, where a forest transition has been suggested. A review of literature and secondary data on forest and ecosystem services in Costa Rica indicated that forest transition might have led to an ecosystem services transition. We modeled and mapped the changes of selected ecosystem services in the upper part of the Reventazón watershed and analyzed how supply changed over time in order to identify possible transitions in ecosystem services. The modeled changes of ecosystem services is similar to the second phase of a forest transition but no turning point was identified, probably because of the limited temporal scope of the analysis. Trends of provisioning and regulating services and their tradeoffs were opposite in different spatial subunits of our study area, which highlights the importance of scale in the analysis of ecosystem services and forest transitions. The ecosystem services transition framework proposed in this study is useful for analyzing the temporal changes of ecosystem services and linking socio-economic drivers to ecosystem services demand at different scales. PMID:27390869

  13. Dynamics of Ecosystem Services during Forest Transitions in Reventazón, Costa Rica.

    PubMed

    Vallet, Améline; Locatelli, Bruno; Levrel, Harold; Brenes Pérez, Christian; Imbach, Pablo; Estrada Carmona, Natalia; Manlay, Raphaël; Oszwald, Johan

    2016-01-01

    The forest transition framework describes the temporal changes of forest areas with economic development. A first phase of forest contraction is followed by a second phase of expansion once a turning point is reached. This framework does not differentiate forest types or ecosystem services, and describes forests regardless of their contribution to human well-being. For several decades, deforestation in many tropical regions has degraded ecosystem services, such as watershed regulation, while increasing provisioning services from agriculture, for example, food. Forest transitions and expansion have been observed in some countries, but their consequences for ecosystem services are often unclear. We analyzed the implications of forest cover change on ecosystem services in Costa Rica, where a forest transition has been suggested. A review of literature and secondary data on forest and ecosystem services in Costa Rica indicated that forest transition might have led to an ecosystem services transition. We modeled and mapped the changes of selected ecosystem services in the upper part of the Reventazón watershed and analyzed how supply changed over time in order to identify possible transitions in ecosystem services. The modeled changes of ecosystem services is similar to the second phase of a forest transition but no turning point was identified, probably because of the limited temporal scope of the analysis. Trends of provisioning and regulating services and their tradeoffs were opposite in different spatial subunits of our study area, which highlights the importance of scale in the analysis of ecosystem services and forest transitions. The ecosystem services transition framework proposed in this study is useful for analyzing the temporal changes of ecosystem services and linking socio-economic drivers to ecosystem services demand at different scales. PMID:27390869

  14. Unresolving the "real age" of fine roots in forest ecosystems

    NASA Astrophysics Data System (ADS)

    Solly, Emily; Brunner, Ivano; Herzog, Claude; Schöning, Ingo; Schrumpf, Marion; Schweigruber, Fritz; Trumbore, Susan; Hagedorn, Frank

    2016-04-01

    Estimating the turnover time of tree fine roots is crucial for modelling soil organic matter dynamics, but it is one of the biggest challenges in soil ecology and one of the least understood aspects of the belowground carbon cycle. The methods used - ranging from radiocarbon to ingrowth cores and root cameras (minirhizotrons) - yield very diverse pictures of fine root dynamics in forest ecosystems with turnover rates reaching from less than one year to decades. These have huge implications on estimates of carbon allocation to root growth and maintenance and on the persistence of root carbon in soils before it is decomposed or leached. We will present a new approach, involving techniques to study plant anatomy, which unravels the "real age" of fine roots. For a range of forests with diverse water and nutrient limitations located at different latitudes, we investigated the annual growth rings in the secondary xylem of thin transversal sections of fine roots belonging to tree species which form distinct growth rings. In temperate forests we find mean root "ring ages" of 1-2 years while in sub-arctic forests living fine roots can also persist for several years. The robustness of these results were tested by counting the maximum yearly growth rings in tree seedlings of known age and by counting the maximum number of growth rings of fine roots grown in ingrowth cores which were kept in temperate forest soils for one and two years. Radiocarbon estimates of mean "carbon ages", which define the time elapsed since structural carbon was fixed from the atmosphere, instead average around a decade in root systems of temperate forests (mixture of newly produced and older living roots). This dramatic difference may not be related to methodological bias, but to a time lag between C assimilation and production of a portion of fine root tissues due to the storage of older carbon components. The time lag depends very likely on tree species and environmental conditions. We further

  15. Effects of atmospheric pollutants on forests, wetlands, and agricultural ecosystems

    SciTech Connect

    Hutchinson, T.C.; Meema, K.M.

    1987-01-01

    This book reports on the knowledge of the sensitivities and responses of forests, wetlands and crops to airborne pollutants. Pollutants examined include: acidic depositions, heavy metal particulates, sulphur dioxide, ozone, nitrogen oxides, acid fogs, and mixtures of these. Various types of ecosystem stresses and physiological mechanisms pertinent to acid deposition are also discussed. Related subjects, such as the effects of ethylene on vegetation, the physiology of drought in trees, the ability of soils to generate acidity naturally, the role of Sphagnum moss in natural peatland acidity, the use of lichens as indicators of changing air quality, and the magnitude of natural emissions of reduced sulphur gases from tropical rainforests and temperate deciduous forests, are covered.

  16. Heterogeneity of hemiboreal forests in relation to ecosystems functioning.

    NASA Astrophysics Data System (ADS)

    Krasnov, Dmitrii; Noe, Steffen M.; Krasnova, Alisa; Niinemets, Ülo

    2015-04-01

    Heterogeneity is one of the key components of sustainable development of every living system. It provides the source for restocking of ecosystem living components, irregular distribution of nutrients and habitats. Main components of forest horizontal heterogeneity are related with horizontal distribution of dominant species, soil properties, topography and as natural as human disturbances. Soil as the main source for nutrients supply plays essential role in functioning terrestrial ecosystems. The understanding of spatial distribution principles of such soil properties as soil acidity, nutrients available for living organisms, soil moisture and temperature, soil density and the role of tree dominant and co-dominant species can give deeper knowledge about ecosystem functioning. Models based on this knowledge can be more precise and give possibilities to predict more exactly the behavior of ecosystem in terms of global climate changing. The aim of the project is to assess spatial distribution and changes in soil properties related to spatial distribution of vegetation, microtopography and landscape position. For this purpose we used 3D modelling of sample plots and soil profiles using photogrammetry. PhotoModelerScanner software from EOS System Inc. was used to create 3D models from photogrammetric images and GIS technology was used for soil mapping. The project was done in the frame of SMEAR Estonia.

  17. Soil Organic Matter in Forest Ecosystems of the Forest-tundra zone of Central Siberia

    NASA Astrophysics Data System (ADS)

    Mukhortova, Liudmila

    2010-05-01

    Our study was conducted on 17 forest sample plots in the forest-tundra zone of Central Siberia, Krasnoyarsk region, Russia. They were covered by larch/feather moss/shrub and larch/grass forest types growing on cryozems and podburs (Cryosols). The investigation was aimed at estimating soil organic matter storage and structure in forest ecosystems growing along the northern tree line. Such ecosystems have low rates of exchange processes and biological productivity. Estimating soil carbon in these forest types is important for a deeper understanding of their role in biogeochemical cycles and forecasting consequences of climate changes. Soil organic matter was divided into pools by biodegradation resistance level and, hence, different roles of these pools in biological cycles. The soil organic matter was divided into an easily mineralizable (LMOM) fraction, which includes labile (insoluble) (LOM) and mobile (soluble) (MOM) organic compounds, and a stable organic matter fraction that is humus substances bound with soil matrix. The forest-tundra soil carbon was found to total 30.9 to 125.9 tons/ha. Plant residues were the main part of the soil easily mineralizable organic matter and contained from 13.3 to 62.4% of this carbon. Plant residue carbon was mainly allocated on the soil surface, in the forest litter. Plant residues in the soil (dead roots + other "mortmass") were calculated to contribute 10-30% of the plant residues carbon, or 2.5-15.1% of the total soil carbon. Soil surface and in-soil dead plant material included 60-95% of heavily decomposed residues that made up a forest litter fermentation subhorizon and an "other mortmass" fraction of the root detritus. Mobile organic matter (substances dissolved in water and 0.1N NaOH) of plant residues was found to allocate 15-25% of carbon. In soil humus, MOM contribution ranged 14 to 64%. Easily mineralizable organic matter carbon appeared to generally dominate forest-tundra soil carbon pool. It was measured to

  18. Influence of spring and autumn phenological transitions on forest ecosystem productivity.

    PubMed

    Richardson, Andrew D; Black, T Andy; Ciais, Philippe; Delbart, Nicolas; Friedl, Mark A; Gobron, Nadine; Hollinger, David Y; Kutsch, Werner L; Longdoz, Bernard; Luyssaert, Sebastiaan; Migliavacca, Mirco; Montagnani, Leonardo; Munger, J William; Moors, Eddy; Piao, Shilong; Rebmann, Corinna; Reichstein, Markus; Saigusa, Nobuko; Tomelleri, Enrico; Vargas, Rodrigo; Varlagin, Andrej

    2010-10-12

    We use eddy covariance measurements of net ecosystem productivity (NEP) from 21 FLUXNET sites (153 site-years of data) to investigate relationships between phenology and productivity (in terms of both NEP and gross ecosystem photosynthesis, GEP) in temperate and boreal forests. Results are used to evaluate the plausibility of four different conceptual models. Phenological indicators were derived from the eddy covariance time series, and from remote sensing and models. We examine spatial patterns (across sites) and temporal patterns (across years); an important conclusion is that it is likely that neither of these accurately represents how productivity will respond to future phenological shifts resulting from ongoing climate change. In spring and autumn, increased GEP resulting from an 'extra' day tends to be offset by concurrent, but smaller, increases in ecosystem respiration, and thus the effect on NEP is still positive. Spring productivity anomalies appear to have carry-over effects that translate to productivity anomalies in the following autumn, but it is not clear that these result directly from phenological anomalies. Finally, the productivity of evergreen needleleaf forests is less sensitive to phenology than is productivity of deciduous broadleaf forests. This has implications for how climate change may drive shifts in competition within mixed-species stands.

  19. The role of forest floor and trees to the ecosystem scale methane budget of boreal forests

    NASA Astrophysics Data System (ADS)

    Pihlatie, Mari; Halmeenmäki, Elisa; Peltola, Olli; Haikarainen, Iikka; Heinonsalo, Jussi; Santalahti, Minna; Putkinen, Anuliina; Fritze, Hannu; Urban, Otmar; Machacova, Katerina

    2016-04-01

    Boreal forests are considered as a sink of atmospheric methane (CH4) due to the activity of CH4 oxidizing bacteria (methanotrophs) in the soil. This soil CH4 sink is especially strong for upland forest soils, whereas forests growing on organic soils may act as small sources due to the domination of CH4 production by methanogens in the anaerobic parts of the soil. The role of trees to the ecosystem-scale CH4 fluxes has until recently been neglected due to the perception that trees do not contribute to the CH4 exchange, and also due to difficulties in measuring the CH4 exchange from trees. Findings of aerobic CH4 formation in plants and emissions from tree-stems in temperate and tropical forests during the past decade demonstrate that our understanding of CH4 cycling in forest ecosystems is not complete. Especially the role of forest canopies still remain unresolved, and very little is known of CH4 fluxes from trees in boreal region. We measured the CH4 exchange of tree-stems and tree-canopies from pine (Pinus sylvestris), spruce (Picea abies) and birch (Betula pubescens, Betula pendula) trees growing in Southern Finland (SMEAR II station) on varying soil conditions, from upland mineral soils to paludified soil. We compared the CH4 fluxes from trees to forest-floor CH4 exchange, both measured by static chambers, and to CH4 fluxes measured above the forest canopy by a flux gradient technique. We link the CH4 fluxes from trees and forest floor to physiological activity of the trees, such as transpiration, sap-flow, CO2 net ecosystem exchange (NEE), soil properties such as temperature and moisture, and to the presence of CH4 producing methanogens and CH4 oxidizing methanotrophs in trees or soil. The above canopy CH4 flux measurements show that the whole forest ecosystem was a small source of CH4 over extended periods in the spring and summer 2012, 2014 and 2015. Throughout the 2013-2014 measurements, the forest floor was in total a net sink of CH4, with variation

  20. Transport and fate of trifluoroacetate in upland forest and wetland ecosystems.

    PubMed

    Likens, G E; Tartowski, S L; Berger, T W; Richey, D G; Driscoll, C T; Frank, H G; Klein, A

    1997-04-29

    Although trifluoroacetate (TFA), a breakdown product of chlorofluorocarbon replacements, is being dispersed widely within the biosphere, its ecological fate is largely unknown. TFA was added experimentally to an upland, northern hardwood forest and to a small forest wetland ecosystem within the Hubbard Brook Experimental Forest in New Hampshire. Inputs of TFA were not transported conservatively through these ecosystems; instead, significant amounts of TFA were retained within the vegetation and soil compartments. More TFA was retained by the wetland ecosystem than by the upland forest ecosystem. Using simulation modeling, TFA concentrations were predicted for soil and drainage water until the year 2040.

  1. Transport and fate of trifluoroacetate in upland forest and wetland ecosystems

    SciTech Connect

    Likens, G.E.; Tartowski, S.L.; Berger, T.W.

    1997-04-29

    Although trifluoroacetate (TFA), a breakdown product of chlorofluorocarbon replacements, is being dispersed widely within the biosphere, its ecological fate is largely unknown. TFA was added experimentally to an upland, northern hardwood forest and to a small forest wetland ecosystem within the Hubbard Brook Experimental Forest in New Hampshire. Inputs of TFA were not transported conservatively through these ecosystems; instead, significant amounts of TFA were retained within the vegetation and soil compartments. More TFA was retained by the wetland ecosystem than by the upland forest ecosystem. Using simulation modeling, TFA concentrations were predicted for soil and drainage water until the year 2040. 32 refs., 5 figs., 1 tab.

  2. Transfer parameter values in temperate forest ecosystems: a review.

    PubMed

    Calmon, Philippe; Thiry, Yves; Zibold, Gregor; Rantavaara, Aino; Fesenko, Sergei

    2009-09-01

    Compared to agricultural lands, forests are complex ecosystems as they can involve diverse plant species associations, several vegetative strata (overstorey, shrubs, herbaceous and other annual plant layer) and multi-layered soil profiles (forest floor, hemi-organic and mineral layers). A high degree of variability is thus generally observed in radionuclide transfers and redistribution patterns in contaminated forests. In the long term, the soil compartment represents the major reservoir of radionuclides which can give rise to long-term plant and hence food contamination. For practical reasons, the contamination of various specific forest products has commonly been quantified using the aggregated transfer factor (T(ag) in m(2)kg(-1)) which integrates various environmental parameters including soil and plant type, root distribution as well as nature and vertical distribution of the deposits. Long lasting availability of some radionuclides was shown to be the source of much higher transfer in forest ecosystems than in agricultural lands. This study aimed at reviewing the most relevant quantitative information on radionuclide transfers to forest biota including trees, understorey vegetation, mushrooms, berries and game animals. For both radiocaesium and radiostrontium in trees, the order of magnitude of mean T(ag) values was 10(-3)m(2)kg(-1) (dry weight). Tree foliage was usually 2-12 times more contaminated than trunk wood. Maximum contamination of tree components with radiocaesium was associated with (semi-)hydromorphic areas with thick humus layers. The transfer of radionuclides to mushrooms and berries is high, in comparison with foodstuffs grown in agricultural systems. Concerning caesium uptake by mushrooms, the transfer is characterized by a very large variability of T(ag), from 10(-3) to 10(1)m(2)kg(-1) (dry weight). For berries, typical values are around 0.01-0.1 m(2)kg(-1) (dry weight). Transfer of radioactive caesium to game animals and reindeer and the

  3. Managing forests as ecosystems: A success story or a challenge ahead?

    SciTech Connect

    Dale, V.H.

    1997-10-01

    To manage forests as ecosystems, the many values they hold for different users must be recognized, and they must be used so that those assets are not destroyed. Important ecosystem features of forests include nutrient cycling, habitat, succession, and water quality. Over time, the ways in which humans value forests have changed as forest uses have altered and as forests have declined in size and quality. Both ecosystem science and forest ecology have developed approaches that are useful to manage forests to retain their value. A historical perspective shows how changes in ecology, legislation, and technology have resulted in modern forest-management practices. However, current forest practices are still a decade or so behind current ecosystem science. Ecologists have done a good job of transferring their theories and approaches to the forest manager classroom but have done a poor job of translating these concepts into practice. Thus, the future for ecosystem management requires a closer linkage between ecologists and other disciplines. For example, the changing ways in which humans value forests are the primary determinant of forest-management policies. Therefore, if ecologists are to understand how ecosystem science can influence these policies, they must work closely with social scientists trained to assess human values.

  4. Forest Fragmentation and Selective Logging Have Inconsistent Effects on Multiple Animal-Mediated Ecosystem Processes in a Tropical Forest

    PubMed Central

    Schleuning, Matthias; Farwig, Nina; Peters, Marcell K.; Bergsdorf, Thomas; Bleher, Bärbel; Brandl, Roland; Dalitz, Helmut; Fischer, Georg; Freund, Wolfram; Gikungu, Mary W.; Hagen, Melanie; Garcia, Francisco Hita; Kagezi, Godfrey H.; Kaib, Manfred; Kraemer, Manfred; Lung, Tobias; Schaab, Gertrud; Templin, Mathias; Uster, Dana; Wägele, J. Wolfgang; Böhning-Gaese, Katrin

    2011-01-01

    Forest fragmentation and selective logging are two main drivers of global environmental change and modify biodiversity and environmental conditions in many tropical forests. The consequences of these changes for the functioning of tropical forest ecosystems have rarely been explored in a comprehensive approach. In a Kenyan rainforest, we studied six animal-mediated ecosystem processes and recorded species richness and community composition of all animal taxa involved in these processes. We used linear models and a formal meta-analysis to test whether forest fragmentation and selective logging affected ecosystem processes and biodiversity and used structural equation models to disentangle direct from biodiversity-related indirect effects of human disturbance on multiple ecosystem processes. Fragmentation increased decomposition and reduced antbird predation, while selective logging consistently increased pollination, seed dispersal and army-ant raiding. Fragmentation modified species richness or community composition of five taxa, whereas selective logging did not affect any component of biodiversity. Changes in the abundance of functionally important species were related to lower predation by antbirds and higher decomposition rates in small forest fragments. The positive effects of selective logging on bee pollination, bird seed dispersal and army-ant raiding were direct, i.e. not related to changes in biodiversity, and were probably due to behavioural changes of these highly mobile animal taxa. We conclude that animal-mediated ecosystem processes respond in distinct ways to different types of human disturbance in Kakamega Forest. Our findings suggest that forest fragmentation affects ecosystem processes indirectly by changes in biodiversity, whereas selective logging influences processes directly by modifying local environmental conditions and resource distributions. The positive to neutral effects of selective logging on ecosystem processes show that the

  5. Overlaps among phenological phases in flood plain forest ecosystem

    NASA Astrophysics Data System (ADS)

    Bartošová, Lenka; Bauer, Zdeněk; Trnka, Miroslav; Možný, Martin; Štěpánek, Petr; Žalud, Zdeněk

    2015-04-01

    There is a growing concern that climate change has significant impacts on species phenology, seasonal population dynamics, and thus interaction (a)synchrony between species. Species that have historically undergone life history events on the same seasonal calendar may lose synchrony and therefore lose the ability to interact as they have in the past. In view of the match/mismatch hypothesis, the different extents or directions of the phenological shifts among interacting species may have significant implications for community structure and dynamics. That's why our principal goal of the study is to determine the phenological responses within the ecosystem of flood plain forest and analyzed the phenological overlapping among each phenological periods of given species. The phenological observations were done at flood-plain forest experimental site during the period 1961-2012. The whole ecosystem in this study create 17 species (15 plants and 2 bird species) and each species is composed of 2 phenological phases. Phenological periods of all species of ecosystem overlap each other and 43 of these overlapping were chosen and the length, trend and correlation with temperature were elaborated. The analysis of phenophases overlapping of chosen species showed that the length of overlay is getting significantly shorter in 1 case. On the other hand the situation when the length of overlaps is getting significantly longer arose in 4 cases. Remaining overlaps (38) of all phenological periods among various species is getting shorter or longer but with no significance or have not changed anyhow. This study was funded by project "Building up a multidisciplinary scientific team focused on drought" No. CZ.1.07/2.3.00/20.0248. and of projects no. LD13030 supporting participation of the Czech Republic in the COST action ES1106.

  6. Assessing the ecosystem service potential of Tucson AZ's urban forest

    NASA Astrophysics Data System (ADS)

    Pavao-Zuckerman, M.

    2011-12-01

    canopy photos) to asses growth of the trees in the urban environment. These growth rates, and associated ecosystem services (C-sequestration, energy savings, pollution mitigation, etc.) are evaluated using US Forest Service models (Tree Carbon Calculator and i-tree software) to determine how the performance of trees in the Tucson urban environment perform vs. model predictions. We hypothesize that the models overestimate tree performance as Tucson differs in water availability relative to the cities the model was parameterized in (e.g. Glendale), both in terms of soil water holding capacities and also city "water culture." This preliminary study will provide a data collection framework for a citizen science urban forestry project which will provide data to improve environmental decision making related to the interaction of plants, water, and energy balance in this arid city.

  7. FOREST ECOLOGY. Pervasive drought legacies in forest ecosystems and their implications for carbon cycle models.

    PubMed

    Anderegg, W R L; Schwalm, C; Biondi, F; Camarero, J J; Koch, G; Litvak, M; Ogle, K; Shaw, J D; Shevliakova, E; Williams, A P; Wolf, A; Ziaco, E; Pacala, S

    2015-07-31

    The impacts of climate extremes on terrestrial ecosystems are poorly understood but important for predicting carbon cycle feedbacks to climate change. Coupled climate-carbon cycle models typically assume that vegetation recovery from extreme drought is immediate and complete, which conflicts with the understanding of basic plant physiology. We examined the recovery of stem growth in trees after severe drought at 1338 forest sites across the globe, comprising 49,339 site-years, and compared the results with simulated recovery in climate-vegetation models. We found pervasive and substantial "legacy effects" of reduced growth and incomplete recovery for 1 to 4 years after severe drought. Legacy effects were most prevalent in dry ecosystems, among Pinaceae, and among species with low hydraulic safety margins. In contrast, limited or no legacy effects after drought were simulated by current climate-vegetation models. Our results highlight hysteresis in ecosystem-level carbon cycling and delayed recovery from climate extremes. PMID:26228147

  8. Passive nighttime warming facility for forest ecosystem research.

    PubMed

    Luxmoore, R. J.; Hanson, P. J.; Beauchamp, J. J.; Joslin, J. D.

    1998-01-01

    A nighttime warming experiment is proposed. Over the last four decades a significant rise in nighttime minimum temperature has been determined from analysis of meteorological records from a global distribution of locations. The experiment involves nighttime deployment of infrared (IR) reflecting curtains around four sides of a forest canopy and across the top of the forest to mimic the top-down warming effect of cloud cover. The curtains are deployed with cable and pulley systems mounted on a tower and scaffolding structure built around the selected forest site. The trunk space is not enclosed except as an optional manipulation. The curtains reflect long-wave radiation emitted from the forest and ground back into the forest warming the trees, litter, and soil. Excellent infrared reflection can be obtained with commercially available fabrics that have aluminum foil bonded to one side. A canopy warming of 3 to 5 degrees C is expected on cloudless nights, and on cloudy nights, a warming of 1 to 3 degrees C is anticipated relative to a control plot. The curtains are withdrawn by computer control during the day and also at night during periods with precipitation or excessive wind. Examples of hypothesized ecosystem responses to nighttime warming include: (1) increase in tree maintenance respiration (decreasing carbon reserves and ultimately tree growth), (2) increase in the length of the growing season (increasing growth), (3) increase in soil respiration, (4) increase in litter decomposition, (5) increase in mineralization of N and other nutrients from soil organic matter, (6) increase in nutrient uptake (increasing growth), and (7) increase in N immobilization in litter. Hypothesis 1 has the opposite consequence for tree growth to Hypotheses 2 and 6, and thus opposite consequences for the feedback regulation that vegetation has on net greenhouse gas releases to the atmosphere. If Hypothesis 1 is dominant, warming could lead to more warming from the additional CO(2

  9. Ecological and geochemical impacts of exotic earthworm dispersal in forest ecosystems of Eastern Canada

    NASA Astrophysics Data System (ADS)

    Drouin, Melanie; Fugere, Martine; Lapointe, Line; Vellend, Mark; Bradley, Robert L.

    2016-04-01

    In Eastern Canada, native earthworm species did not survive the Wisconsin glaciation, which ended over 11,000 years ago. Accordingly, the 17 known Lumbricidae species in the province of Québec were introduced in recent centuries by European settlers. Given that natural migration rates are no more than 5-10 m yr-1, exotic earthworm dispersal across the landscape is presumed to be mediated by human activities, although this assertion needs further validation. In agroecosystems, earthworms have traditionally been considered beneficial soil organisms that facilitate litter decomposition, increase nutrient availability and improve soil structure. However, earthworm activities could also increase soil nutrient leaching and CO2 emissions. Furthermore, in natural forest ecosystems, exotic earthworms may reduce organic forest floors provoking changes in watershed hydrology and loss of habitat for some faunal species. Over the past decade, studies have also suggested a negative effect of exotic earthworms on understory plant diversity, but the underlying mechanisms remain elusive. Finally, there are no studies to our knowledge that have tested the effects of Lumbricidae species on the production of N2O (an important greenhouse gas) in forest ecosystems. We report on a series of field, greenhouse and laboratory studies on the human activities responsible for the dispersal of exotic earthworms, and on their ecological / geochemical impacts in natural forest ecosystems. Our results show: (1) Car tire treads and bait discarded by fishermen are important human vectors driving the dispersal of earthworms into northern temperate forests; (2) Exotic earthworms significantly modify soil physicochemical properties, nutrient cycling, microbial community structure and biomass; (3) Earthworm abundances in the field correlate with a decrease in understory plant diversity; (4) Lumbricus terrestris, an anecic earthworm species and favorite bait of fishermen, reduces seed germination and

  10. Ecological and geochemical impacts of exotic earthworm dispersal in forest ecosystems of Eastern Canada

    NASA Astrophysics Data System (ADS)

    Drouin, Melanie; Fugere, Martine; Lapointe, Line; Vellend, Mark; Bradley, Robert L.

    2016-04-01

    In Eastern Canada, native earthworm species did not survive the Wisconsin glaciation, which ended over 11,000 years ago. Accordingly, the 17 known Lumbricidae species in the province of Québec were introduced in recent centuries by European settlers. Given that natural migration rates are no more than 5-10 m yr‑1, exotic earthworm dispersal across the landscape is presumed to be mediated by human activities, although this assertion needs further validation. In agroecosystems, earthworms have traditionally been considered beneficial soil organisms that facilitate litter decomposition, increase nutrient availability and improve soil structure. However, earthworm activities could also increase soil nutrient leaching and CO2 emissions. Furthermore, in natural forest ecosystems, exotic earthworms may reduce organic forest floors provoking changes in watershed hydrology and loss of habitat for some faunal species. Over the past decade, studies have also suggested a negative effect of exotic earthworms on understory plant diversity, but the underlying mechanisms remain elusive. Finally, there are no studies to our knowledge that have tested the effects of Lumbricidae species on the production of N2O (an important greenhouse gas) in forest ecosystems. We report on a series of field, greenhouse and laboratory studies on the human activities responsible for the dispersal of exotic earthworms, and on their ecological / geochemical impacts in natural forest ecosystems. Our results show: (1) Car tire treads and bait discarded by fishermen are important human vectors driving the dispersal of earthworms into northern temperate forests; (2) Exotic earthworms significantly modify soil physicochemical properties, nutrient cycling, microbial community structure and biomass; (3) Earthworm abundances in the field correlate with a decrease in understory plant diversity; (4) Lumbricus terrestris, an anecic earthworm species and favorite bait of fishermen, reduces seed germination and

  11. Significant increase in ecosystem C can be achieved with sustainable forest management in subtropical plantation forests.

    PubMed

    Wei, Xiaohua; Blanco, Juan A

    2014-01-01

    Subtropical planted forests are rapidly expanding. They are traditionally managed for intensive, short-term goals that often lead to long-term yield decline and reduced carbon sequestration capacity. Here we show how it is possible to increase and sustain carbon stored in subtropical forest plantations if management is switched towards more sustainable forestry. We first conducted a literature review to explore possible management factors that contribute to the potentials in ecosystem C in tropical and subtropical plantations. We found that broadleaves plantations have significantly higher ecosystem C than conifer plantations. In addition, ecosystem C increases with plantation age, and reaches a peak with intermediate stand densities of 1500-2500 trees ha⁻¹. We then used the FORECAST model to simulate the regional implications of switching from traditional to sustainable management regimes, using Chinese fir (Cunninghamia lanceolata) plantations in subtropical China as a study case. We randomly simulated 200 traditional short-rotation pure stands and 200 sustainably-managed mixed Chinese fir--Phoebe bournei plantations, for 120 years. Our results showed that mixed, sustainably-managed plantations have on average 67.5% more ecosystem C than traditional pure conifer plantations. If all pure plantations were gradually transformed into mixed plantations during the next 10 years, carbon stocks could rise in 2050 by 260.22 TgC in east-central China. Assuming similar differences for temperate and boreal plantations, if sustainable forestry practices were applied to all new forest plantation types in China, stored carbon could increase by 1,482.80 TgC in 2050. Such an increase would be equivalent to a yearly sequestration rate of 40.08 TgC yr⁻¹, offsetting 1.9% of China's annual emissions in 2010. More importantly, this C increase can be sustained in the long term through the maintenance of higher amounts of soil organic carbon and the production of timber products

  12. Significant Increase in Ecosystem C Can Be Achieved with Sustainable Forest Management in Subtropical Plantation Forests

    PubMed Central

    Wei, Xiaohua; Blanco, Juan A.

    2014-01-01

    Subtropical planted forests are rapidly expanding. They are traditionally managed for intensive, short-term goals that often lead to long-term yield decline and reduced carbon sequestration capacity. Here we show how it is possible to increase and sustain carbon stored in subtropical forest plantations if management is switched towards more sustainable forestry. We first conducted a literature review to explore possible management factors that contribute to the potentials in ecosystem C in tropical and subtropical plantations. We found that broadleaves plantations have significantly higher ecosystem C than conifer plantations. In addition, ecosystem C increases with plantation age, and reaches a peak with intermediate stand densities of 1500–2500 trees ha−1. We then used the FORECAST model to simulate the regional implications of switching from traditional to sustainable management regimes, using Chinese fir (Cunninghamia lanceolata) plantations in subtropical China as a study case. We randomly simulated 200 traditional short-rotation pure stands and 200 sustainably-managed mixed Chinese fir – Phoebe bournei plantations, for 120 years. Our results showed that mixed, sustainably-managed plantations have on average 67.5% more ecosystem C than traditional pure conifer plantations. If all pure plantations were gradually transformed into mixed plantations during the next 10 years, carbon stocks could rise in 2050 by 260.22 TgC in east-central China. Assuming similar differences for temperate and boreal plantations, if sustainable forestry practices were applied to all new forest plantation types in China, stored carbon could increase by 1,482.80 TgC in 2050. Such an increase would be equivalent to a yearly sequestration rate of 40.08 TgC yr−1, offsetting 1.9% of China’s annual emissions in 2010. More importantly, this C increase can be sustained in the long term through the maintenance of higher amounts of soil organic carbon and the production of timber

  13. Carbon account of forest ecosystems as a fuzzy system: a case study for Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Shvidenko, A.; Shchepashchenko, D.; Kraxner, F.; Maksyutov, S. S.

    2015-12-01

    We consider practicality of a verified account of Net Ecosystem Carbon Budget for forest ecosystems (FCA) that supposes reliable assessment of uncertainties, i.e. understanding "uncertainty of uncertainties". The FCA is a fuzzy (underspecified) system, of which membership function is inherently stochastic. Thus, any individually used method of FCA is not able to estimate structural uncertainties and usually reported "within method" uncertainties are inevitably partial. Attempting at estimation of "full uncertainties" of the studied system we follow the requirements of applied systems analysis integrating the major methods of terrestrial ecosystems carbon account, assessing the uncertainties "within method" for intermediate and final indicators of FCA with their following mutual constrains. Landscape-ecosystem approach (LEA) 1) serves for strict systems designing the account, 2) contains all relevant spatially distributed empirical and semi-empirical data and models, and 3) is presented in form of an Integrated Land Information System (ILIS). By-pixel parametrization of forest cover is provided by utilizing multi-sensor remote sensing data (12 RS products used) within GEO-wiki platform and other relevant information based on special optimization algorithms. Major carbon fluxes within the LEA (NPP, HR, disturbances etc.) are estimated based on fusion of empirical data with process-based elements by sets of regionally distributed models. Uncertainties within LEA are assessed for each module and at each step of the account. "Within method" results and uncertainties (including LEA, process-based models, eddy covariance, and inverse modelling) are harmonized based on the Bayesian approach. The above methodology have been applied to carbon account of Russian forests for 2000-2010; uncertainties of the FCA for individual years were estimated in limits of 25%. We discussed strengths and weaknesses of the approach, system requirements to different methods of FCA, information

  14. Forest Management Type Influences Diversity and Community Composition of Soil Fungi across Temperate Forest Ecosystems

    PubMed Central

    Goldmann, Kezia; Schöning, Ingo; Buscot, François; Wubet, Tesfaye

    2015-01-01

    Fungal communities have been shown to be highly sensitive toward shifts in plant diversity and species composition in forest ecosystems. However, little is known about the impact of forest management on fungal diversity and community composition of geographically separated sites. This study examined the effects of four different forest management types on soil fungal communities. These forest management types include age class forests of young managed beech (Fagus sylvatica L.), with beech stands age of approximately 30 years, age class beech stands with an age of approximately 70 years, unmanaged beech stands, and coniferous stands dominated by either pine (Pinus sylvestris L.) or spruce (Picea abies Karst.) which are located in three study sites across Germany. Soil were sampled from 48 study plots and we employed fungal ITS rDNA pyrotag sequencing to assess the soil fungal diversity and community structure. We found that forest management type significantly affects the Shannon diversity of soil fungi and a significant interaction effect of study site and forest management on the fungal operational taxonomic units richness. Consequently distinct fungal communities were detected in the three study sites and within the four forest management types, which were mainly related to the main tree species. Further analysis of the contribution of soil properties revealed that C/N ratio being the most important factor in all the three study sites whereas soil pH was significantly related to the fungal community in two study sites. Functional assignment of the fungal communities indicated that 38% of the observed communities were Ectomycorrhizal fungi (ECM) and their distribution is significantly influenced by the forest management. Soil pH and C/N ratio were found to be the main drivers of the ECM fungal community composition. Additional fungal community similarity analysis revealed the presence of study site and management type specific ECM genera. This study extends our

  15. Herbivory makes major contributions to ecosystem carbon and nutrient cycling in tropical forests.

    PubMed

    Metcalfe, Daniel B; Asner, Gregory P; Martin, Roberta E; Silva Espejo, Javier E; Huasco, Walter Huaraca; Farfán Amézquita, Felix F; Carranza-Jimenez, Loreli; Galiano Cabrera, Darcy F; Baca, Liliana Durand; Sinca, Felipe; Huaraca Quispe, Lidia P; Taype, Ivonne Alzamora; Mora, Luzmila Eguiluz; Dávila, Angela Rozas; Solórzano, Marlene Mamani; Puma Vilca, Beisit L; Laupa Román, Judith M; Guerra Bustios, Patricia C; Revilla, Norma Salinas; Tupayachi, Raul; Girardin, Cécile A J; Doughty, Christopher E; Malhi, Yadvinder

    2014-03-01

    The functional role of herbivores in tropical rainforests remains poorly understood. We quantified the magnitude of, and underlying controls on, carbon, nitrogen and phosphorus cycled by invertebrate herbivory along a 2800 m elevational gradient in the tropical Andes spanning 12°C mean annual temperature. We find, firstly, that leaf area loss is greater at warmer sites with lower foliar phosphorus, and secondly, that the estimated herbivore-mediated flux of foliar nitrogen and phosphorus from plants to soil via leaf area loss is similar to, or greater than, other major sources of these nutrients in tropical forests. Finally, we estimate that herbivores consume a significant portion of plant carbon, potentially causing major shifts in the pattern of plant and soil carbon cycling. We conclude that future shifts in herbivore abundance and activity as a result of environmental change could have major impacts on soil fertility and ecosystem carbon sequestration in tropical forests. PMID:24372865

  16. Sinks for Inorganic Nitrogen Deposition in Forest Ecosystems with Low and High Nitrogen Deposition in China

    PubMed Central

    Sheng, Wenping; Yu, Guirui; Fang, Huajun; Jiang, Chunming; Yan, Junhua; Zhou, Mei

    2014-01-01

    We added the stable isotope 15N in the form of (15NH4)2SO4 and K15NO3 to forest ecosystems in eastern China under two different N deposition levels to study the fate of the different forms of deposited N. Prior to the addition of the 15N tracers, the natural 15N abundance ranging from −3.4‰ to +10.9‰ in the forest under heavy N deposition at Dinghushan (DHS), and from −3.92‰ to +7.25‰ in the forest under light N deposition at Daxinganling (DXAL). Four months after the tracer application, the total 15N recovery from the major ecosystem compartments ranged from 55.3% to 90.5%. The total 15N recoveries were similar under the (15NH4)2SO4 tracer treatment in both two forest ecosystems, whereas the total 15N recovery was significantly lower in the subtropical forest ecosystem at DHS than in the boreal forest ecosystem at DXAL under the K15NO3 tracer treatment. The 15N assimilated into the tree biomass represented only 8.8% to 33.7% of the 15N added to the forest ecosystems. In both of the tracer application treatments, more 15N was recovered from the tree biomass in the subtropical forest ecosystem at DHS than the boreal forest ecosystem at DXAL. The amount of 15N assimilated into tree biomass was greater under the K15NO3 tracer treatment than that of the (15NH4)2SO4 treatment in both forest ecosystems. This study suggests that, although less N was immobilized in the forest ecosystems under more intensive N deposition conditions, forest ecosystems in China strongly retain N deposition, even in areas under heavy N deposition intensity or in ecosystems undergoing spring freezing and thawing melts. Compared to ammonium deposition, deposited nitrate is released from the forest ecosystem more easily. However, nitrate deposition could be retained mostly in the plant N pool, which might lead to more C sequestration in these ecosystems. PMID:24586688

  17. Climate Change and Ecosystem Services Output Efficiency in Southern Loblolly Pine Forests.

    PubMed

    Susaeta, Andres; Adams, Damian C; Carter, Douglas R; Dwivedi, Puneet

    2016-09-01

    Forests provide myriad ecosystem services that are vital to humanity. With climate change, we expect to see significant changes to forests that will alter the supply of these critical services and affect human well-being. To better understand the impacts of climate change on forest-based ecosystem services, we applied a data envelopment analysis method to assess plot-level efficiency in the provision of ecosystem services in Florida natural loblolly pine (Pinus taeda L.) forests. Using field data for n = 16 loblolly pine forest plots, including inputs such as site index, tree density, age, precipitation, and temperatures for each forest plot, we assessed the relative plot-level production of three ecosystem services: timber, carbon sequestered, and species richness. The results suggested that loblolly pine forests in Florida were largely inefficient in the provision of these ecosystem services under current climatic conditions. Climate change had a small negative impact on the loblolly pine forests efficiency in the provision of ecosystem services. In this context, we discussed the reduction of tree density that may not improve ecosystem services production. PMID:27263100

  18. Climate Change and Ecosystem Services Output Efficiency in Southern Loblolly Pine Forests.

    PubMed

    Susaeta, Andres; Adams, Damian C; Carter, Douglas R; Dwivedi, Puneet

    2016-09-01

    Forests provide myriad ecosystem services that are vital to humanity. With climate change, we expect to see significant changes to forests that will alter the supply of these critical services and affect human well-being. To better understand the impacts of climate change on forest-based ecosystem services, we applied a data envelopment analysis method to assess plot-level efficiency in the provision of ecosystem services in Florida natural loblolly pine (Pinus taeda L.) forests. Using field data for n = 16 loblolly pine forest plots, including inputs such as site index, tree density, age, precipitation, and temperatures for each forest plot, we assessed the relative plot-level production of three ecosystem services: timber, carbon sequestered, and species richness. The results suggested that loblolly pine forests in Florida were largely inefficient in the provision of these ecosystem services under current climatic conditions. Climate change had a small negative impact on the loblolly pine forests efficiency in the provision of ecosystem services. In this context, we discussed the reduction of tree density that may not improve ecosystem services production.

  19. Climate Change and Ecosystem Services Output Efficiency in Southern Loblolly Pine Forests

    NASA Astrophysics Data System (ADS)

    Susaeta, Andres; Adams, Damian C.; Carter, Douglas R.; Dwivedi, Puneet

    2016-09-01

    Forests provide myriad ecosystem services that are vital to humanity. With climate change, we expect to see significant changes to forests that will alter the supply of these critical services and affect human well-being. To better understand the impacts of climate change on forest-based ecosystem services, we applied a data envelopment analysis method to assess plot-level efficiency in the provision of ecosystem services in Florida natural loblolly pine ( Pinus taeda L.) forests. Using field data for n = 16 loblolly pine forest plots, including inputs such as site index, tree density, age, precipitation, and temperatures for each forest plot, we assessed the relative plot-level production of three ecosystem services: timber, carbon sequestered, and species richness. The results suggested that loblolly pine forests in Florida were largely inefficient in the provision of these ecosystem services under current climatic conditions. Climate change had a small negative impact on the loblolly pine forests efficiency in the provision of ecosystem services. In this context, we discussed the reduction of tree density that may not improve ecosystem services production.

  20. Cadmium in forest ecosystems around lead smelters in Missouri.

    PubMed Central

    Gale, N L; Wixson, B G

    1979-01-01

    The development of Missouri's new lead belt within the past decase has provided an excellent opportunity to study the dissemination and effects of heavy metals in a deciduous forest ecosystem. Primary lead smelters within the new lead belt have been identified as potential sources of cadmium as well as lead, zinc, and copper. Sintering and blast furnace operations tend to produce significant quantities of small particulates highly enriched in cadmium and other heavy metals. At one smelter, samples of stack particulate emissions indicate that as ms accompanied by 0.44 lb zinc, 4.66 lb lead, and 0.01 lb copper/hr. These point-source emissions, as well as a number of other sources of fugitive (wind blown) and waterborne emissions contribute to a significant deposition of cadmium in the surrounding forest and stream beds. Mobilization of vagrant heavy metals may be significantly increased by contact of baghouse dusts or scrubber slurries with acidic effluents emanating from acid plants designed to produce H2SO4 as a smelter by-product. Two separate drainage forks within the Crooked Creek watershed permit some comparisons of the relative contributions of cadmium by air-borne versus water-borne contaminants. Cadmium and other heavy metals have been found to accumulate in the forest litter and partially decomposed litter along stream beds. Greater solubility, lower levels of complexation with organic ligands in the litter, and greater overall mobility of cadmium compared with lead, zinc, and copper result in appreciable contributions of dissolved cadmium to the watershed runoff. The present paper attempts to define the principle sources and current levels of heavy metal contamination and summarizes the efforts undertaken by the industry to curtail the problem. PMID:488037

  1. Cadmium in forest ecosystems around lead smelters in Missouri.

    PubMed

    Gale, N L; Wixson, B G

    1979-02-01

    The development of Missouri's new lead belt within the past decase has provided an excellent opportunity to study the dissemination and effects of heavy metals in a deciduous forest ecosystem. Primary lead smelters within the new lead belt have been identified as potential sources of cadmium as well as lead, zinc, and copper. Sintering and blast furnace operations tend to produce significant quantities of small particulates highly enriched in cadmium and other heavy metals. At one smelter, samples of stack particulate emissions indicate that as ms accompanied by 0.44 lb zinc, 4.66 lb lead, and 0.01 lb copper/hr. These point-source emissions, as well as a number of other sources of fugitive (wind blown) and waterborne emissions contribute to a significant deposition of cadmium in the surrounding forest and stream beds. Mobilization of vagrant heavy metals may be significantly increased by contact of baghouse dusts or scrubber slurries with acidic effluents emanating from acid plants designed to produce H2SO4 as a smelter by-product. Two separate drainage forks within the Crooked Creek watershed permit some comparisons of the relative contributions of cadmium by air-borne versus water-borne contaminants. Cadmium and other heavy metals have been found to accumulate in the forest litter and partially decomposed litter along stream beds. Greater solubility, lower levels of complexation with organic ligands in the litter, and greater overall mobility of cadmium compared with lead, zinc, and copper result in appreciable contributions of dissolved cadmium to the watershed runoff. The present paper attempts to define the principle sources and current levels of heavy metal contamination and summarizes the efforts undertaken by the industry to curtail the problem.

  2. FINAL ECOSYSTEM GOODS AND SERVICES CLASSIFICATION SYSTEM (FEGS-CS)

    EPA Science Inventory

    This document defines and classifies 338 Final Ecosystem Goods and Services (FEGS), each defined and uniquely numbered by a combination of environmental class or sub-class and a beneficiary category or sub-category. The introductory section provides the rationale and conceptual ...

  3. Urban forest ecosystem analysis using fused airborne hyperspectral and lidar data

    NASA Astrophysics Data System (ADS)

    Alonzo, Mike Gerard

    Urban trees are strategically important in a city's effort to mitigate their carbon footprint, heat island effects, air pollution, and stormwater runoff. Currently, the most common method for quantifying urban forest structure and ecosystem function is through field plot sampling. However, taking intensive structural measurements on private properties throughout a city is difficult, and the outputs from sample inventories are not spatially explicit. The overarching goal of this dissertation is to develop methods for mapping urban forest structure and function using fused hyperspectral imagery and waveform lidar data at the individual tree crown scale. Urban forest ecosystem services estimated using the USDA Forest Service's i-Tree Eco (formerly UFORE) model are based largely on tree species and leaf area index (LAI). Accordingly, tree species were mapped in my Santa Barbara, California study area for 29 species comprising >80% of canopy. Crown-scale discriminant analysis methods were introduced for fusing Airborne Visible Infrared Imaging Spectrometry (AVIRIS) data with a suite of lidar structural metrics (e.g., tree height, crown porosity) to maximize classification accuracy in a complex environment. AVIRIS imagery was critical to achieving an overall species-level accuracy of 83.4% while lidar data was most useful for improving the discrimination of small and morphologically unique species. LAI was estimated at both the field-plot scale using laser penetration metrics and at the crown scale using allometry. Agreement of the former with photographic estimates of gap fraction and the latter with allometric estimates based on field measurements was examined. Results indicate that lidar may be used reasonably to measure LAI in an urban environment lacking in continuous canopy and characterized by high species diversity. Finally, urban ecosystem services such as carbon storage and building energy-use modification were analyzed through combination of aforementioned

  4. Forest site-quality estimation using Forest Ecosystem Classification in Northwestern Ontario.

    PubMed

    Carmean, W H

    1996-01-01

    Site index for jack pine, black spruce and trembling aspen was found to be poorly related to soil types described in the Northwestern Ontario Forest Ecosystem Classification (NWO FEC). Statistical analyses showed that average site indices for most soil types and groupings of soil types were not significantly different from each other.Site index varies greatly within presently defined NWO FEC soil types because certain soil and topographic features that are closely related to site index vary greatly within soil types or are not well described by the NWO FEC soil types. These critical soil features have been identified by soil-site studies that show features most closely related to site index usually are surface soil features found within the effective rooting zone of forest trees. These critical features include depth to bedrock, depth to root restricting soil layers, and coarse fragment content and texture of surface soil horizons.Site-quality research in Northwestern Ontario is closely integrated with the NWO FEC program, thus future NWO FEC soil classifications probably will use results from our soil-site research as a basis for soil type revisions. The result will be future soil types that are more closely related to forest site quality and thus to the capability of forest land to produce tree growth.

  5. Controls On Water Use Efficiency For Different Forest Ecosystems Across North America: From The Leaf To Landscape

    NASA Astrophysics Data System (ADS)

    Guerrieri, R.; Lepine, L. C.; Asbjornsen, H.; Xiao, J.; Ollinger, S. V.

    2014-12-01

    Water use efficiency (WUE), defined as the ratio of carbon assimilation (A) to water loss via transpiration, is the key physiological parameter that explicitly links water and carbon cycling in forest ecosystems. Most studies examining the influence of climatic factors on forest-WUE have focused on site-specific and water-limited ecosystems. Much less is known about the dynamics of WUE across different forest ecosystems, along gradients of climate and soil nutrients. This study explores the variation in WUE at twelve different forested Ameriflux sites across North America spanning a wide range of forest types and climate conditions. We were interested in answering the following questions: 1) Are patterns of WUE at the tree level similar to those for whole ecosystems? 2) Is there a consistent relationship between foliar nitrogen (N) and WUE at the two different scales? 3) To what extent does species diversity explain forest ecosystem functioning and resilience to drought? Finally, 4) Can changes in GPP, ET and WUE across the studied climate gradient be estimated using remotely derived water indices, such as NDWI? We address these questions through a combination of techniques applied at the leaf to landscape level, including foliar δ13C, δ18O and N, eddy covariance and remote sensing data. At each site, we used foliar δ13C to infer intrinsic WUE (iWUE=A/gs) for the two dominant tree species, while foliar N and δ18O provided insights about the species-specific physiological mechanisms underlying variation in iWUE. Furthermore, we used flux data to derive ET and WUEe (i.e., ecosystem WUE= GPP/ET). Variations in iWUE and WUEe in relation to foliar N, climate parameters and water stress index (PSDI) are considered across sites. Moreover, differences in GPP, ET and WUEe are explored in relation to forest ecosystem type, species richness and Shannon's diversity index. Finally we examine the degree to which changes in WUE are related to NDVI and NDWI.

  6. Analysis of zone of vulnurability and impact of forest fires in forest ecosystems in north algeria by susing remote sensing

    NASA Astrophysics Data System (ADS)

    Zegrar, Ahmed

    2010-05-01

    The Forest in steppe present ecological diversity, and seen climatic unfavourable conditions in zone and impact of forest fires; we notes deterioration of physical environment particularly, deterioration of natural forest. This deterioration of forests provokes an unbalance of environment witch provokes a process of deterioration advanced in the ultimate stadium is desertification. By elsewhere, where climatic conditions are favourable, the fire is an ecological and acted agent like integral part of evolution of the ecosystems, the specific regeneration of plants are influenced greatly by the regime of fire (season of fire, intensity, interval), witch leads to the recuperation of the vegetation of meadow- fire. In this survey we used the pictures ALSAT-1 for detection of zones with risk of forest fire and their impact on the naturals forests in region named TLEMCEN in the north west of Algeria. A thematic detailed analysis of forests well attended ecosystems some processing on the picture ALSAT-1, we allowed to identify and classifying the forests in there opinion components flowers. We identified ampleness of fire on this zone also. Some parameters as the slope, the proximity to the road and the forests formations were studied in the goal of determining the zones to risk of forest fire. A crossing of diaper of information in a GIS according to a very determined logic allowed classifying the zones in degree of risk of fire in semi arid zone witch forest zone not encouraging the regeneration but permitting the installation of cash of steppe which encourages the desertification.

  7. Forest restoration and forest communities: have local communities benefited from forest service contracting of ecosystem management?

    PubMed

    Moseley, Cassandra; Reyes, Yolanda E

    2008-08-01

    Conservation-based development programs have sought to create economic opportunities for people negatively impacted by biological diversity protection. The USDA Forest Service, for example, developed policies and programs to create contracting opportunities for local communities to restore public lands to replace jobs lost from reduced timber harvest. This article examines 12 years of Forest Service land management contracting in western Oregon, Washington, and northern California to evaluate if contractors located in communities near national forests have been awarded more land management contracts and contract value over time. We find that land management contracting spending has declined dramatically and, once we control for intervening factors, we find that local contractors have received a smaller proportion of land management contracts over time.

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

    PubMed

    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. PMID:25267642

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

    PubMed Central

    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

    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 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 (Δδ13CS). Δδ13CS 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. PMID:25267642

  10. Biological effects of wood ash application to forest and aquatic ecosystems.

    PubMed

    Aronsson, K Andreas; Ekelund, Nils G A

    2004-01-01

    The present review aims to summarize current knowledge in the topic of wood ash application to boreal forest and aquatic ecosystems, and the different effects derived from these actions. Much research has been conducted regarding the effects of wood ash application on forest growth. Present studies show that, generally speaking, forest growth can be increased on wood ash-ameliorated peatland rich in nitrogen. On mineral soils, however, no change or even decreased growth have been reported. The effects on ground vegetation are not very clear, as well as the effects on fungi, soil microbes, and soil-decomposing animals. The discrepancies between different studies are for the most part explained by abiotic factors such as variation in fertility among sites, different degrees of stabilization, and wood ash dosage used, and different time scales among different studies. The lack of knowledge in the field of aquatic ecosystems and their response to ash application is an important issue for future research. The few studies conducted have mainly considered changes in water chemistry. The biotoxic effects of ash application can roughly be divided into two categories: primary and secondary. Among the primary effects is toxicity deriving from compounds in the wood ash and cadmium is probably the worst among these. The secondary effects of wood ash are generally due to its alkaline capacity and a release of ions into the soil and soil water, and finally, watercourses and lakes. Given current knowledge, we would recommend site- and wood ash-specific application practices, rather than broad and general guidelines for wood ash application to forests. PMID:15356219

  11. Riparian forests buffer panel final report

    SciTech Connect

    1996-10-01

    The Chesapeake Executive Council adopted Directive 94-1 which called upon the Chesapeake Bay Program to develop a set of goals and actions to increase the focus on riparian stewardship and enhance efforts to conserve and restore riparian forest buffers. The Council appointed a panel to recommend a set of policies, recommend an accepted definition of forest buffers, and suggest quantifiable goals. The Panel was a diverse group of thirty-one members, comprised of federal, state, and local government representatives, scientists, land managers, citizens, and farming, development, forest industry, and environmental interests. This report contains our principal findings and recommendations.

  12. Effects of climate change on forest ecosystems in Iceland

    NASA Astrophysics Data System (ADS)

    Kjartansson, Bjarki; Smith, Ben; Warlind, David; Olafsson, Haraldur

    2013-04-01

    The subartic region has been considered an area of high impact under future climate change senarios. We investigated the climatic effect on the change in potential forest distribution, structure and growth in Iceland from 1900 to 2100 by applying climatic time series to the dynamic vegetation model LPJ-GUESSN. For the historical period we utilized a combination of gridded climatic datasets to create a time series for monthly means of temperature, precipitation and radiation. These datasets where provided by the Icelandic Metrological office (IMO) and the Climatic research unit at East Anglia (CRU). For the future climate we added data from three different general circulation models (GCḾs) where each model had three different representative concentration pathways (RCP). In order to compensate for topographical differences within modeled grid cells we divide each grid cell into elevation zones with 50 meters vertical interval. Each elevation zone is modeled explicitly with downscaled temperature values adjusted for the elevation. This gave us the opportunity to observe different ecosystems with in each grid cell and how they developed over time both horizontally and vertically. We applied the climatic time series to drive the dynamic vegetation model LPJ-GUESSN. The model includes the features of the LPJ-GUESS model with added module where nitrogen is modeled explicitly. The addition of the nitrogen cycle allowed us to examine the nitrogen availability in soils and its effects on vegetation growth. Our results show that under the future scenario there is increased NPP under all RCṔs and GCḾs. We observe a general trend of increase in carbon pool buildup with varying degree around the island. There is an advance in forest limits into higher elevation areas. The lowland areas show a shift in species composition where conifers retreat upward from broadleaved species dominating the lower altitudes into the future. Increased temperature opens up areas in the

  13. Potential increases in natural disturbance rates could offset forest management impacts on ecosystem carbon stocks

    USGS Publications Warehouse

    Bradford, John B.; Jensen, Nicholas R.; Domke, Grant M.; D’Amato, Anthony W.

    2013-01-01

    Forested ecosystems contain the majority of the world’s terrestrial carbon, and forest management has implications for regional and global carbon cycling. Carbon stored in forests changes with stand age and is affected by natural disturbance and timber harvesting. We examined how harvesting and disturbance interact to influence forest carbon stocks over the Superior National Forest, in northern Minnesota. Forest inventory data from the USDA Forest Service, Forest Inventory and Analysis program were used to characterize current forest age structure and quantify the relationship between age and carbon stocks for eight forest types. Using these findings, we simulated the impact of alternative management scenarios and natural disturbance rates on forest-wide terrestrial carbon stocks over a 100-year horizon. Under low natural mortality, forest-wide total ecosystem carbon stocks increased when 0% or 40% of planned harvests were implemented; however, the majority of forest-wide carbon stocks decreased with greater harvest levels and elevated disturbance rates. Our results suggest that natural disturbance has the potential to exert stronger influence on forest carbon stocks than timber harvesting activities and that maintaining carbon stocks over the long-term may prove difficult if disturbance frequency increases in response to climate change.

  14. Global patterns of ecosystem carbon flux in forests: A biometric data-based synthesis

    NASA Astrophysics Data System (ADS)

    Xu, Bing; Yang, Yuanhe; Li, Pin; Shen, Haihua; Fang, Jingyun

    2014-09-01

    Forest ecosystems function as a significant carbon sink for atmospheric carbon dioxide. However, our understanding of global patterns of forest carbon fluxes remains controversial. Here we examined global patterns and environmental controls of forest carbon balance using biometric measurements derived from 243 sites and synthesized from 81 publications around the world. Our results showed that both production and respiration increased with mean annual temperature and exhibited unimodal patterns along a gradient of precipitation. However, net ecosystem production (NEP) initially increased and subsequently declined along gradients of both temperature and precipitation. Our results also indicated that ecosystem production increased during stand development but eventually leveled off, whereas respiration was significantly higher in mature and old forests than in young forests. The residual variation of carbon flux along climatic and age gradients might be explained by other factors such as atmospheric CO2 elevation and disturbances (e.g., forest fire, storm damage, and selective harvest). Heterotrophic respiration (Rh) was positively associated with net primary production (NPP), but the Rh-NPP relationship differed between natural and planted forests: Rh increased exponentially with NPP in natural forests but tended toward saturation with increased NPP in planted forests. Comparison of biometric measurements with eddy covariance observations revealed that ecosystem carbon balance derived from the latter generated higher overall NEP estimates. These results suggest that the eddy covariance observations may overestimate the strength of carbon sinks, and thus, biometric measurements need to be incorporated into global assessments of the forest carbon balance.

  15. [Carbon cycle in ten kinds of forest ecosystem in Guangzhou City].

    PubMed

    Kang, Wen-xing; Tian, Zheng; He, Jie-nan; Cui, Sha-sha

    2009-12-01

    Based on an extensive collection of information and experimental data, this paper studied the carbon cycle in ten kinds of forest ecosystem in Guangzhou, China, aimed to explore the carbon cycling patterns in, southern subtropical forest ecosystems. For the test ecosystems, their carbon density ranged from 108.35 to 151.85 t C x hm(-2), with 10. 85-48.86 t C x hm(-2) in tree layer and 87.74-99.01 t C x hm(-2) in soil layer (0-60 cm), being lower than the national average. There were 4. 41-9. 15 t C x hm(-2) x a(-1) flowed from atmosphere to vegetation stratum, 0. 74-2.06 t C x hm(-2) x a(-1) from vegetation stratum to soil, and 3.94-5.42 t C x hm(-2) x a(-1) from soil to atmosphere, i.e., the forest systems absorbed 0.47-4.97 t C x hm(-2) x a(-1) from atmosphere. The net ecosystem production (NEP) varied with forest stand, being higher for broadleaved forest than coniferous forest, mixed forest than pure forest, and natural secondary forest than artificial forest.

  16. Ca cycling and isotopic fluxes in forested ecosystems in Hawaii

    USGS Publications Warehouse

    Wiegand, B.A.; Chadwick, O.A.; Vitousek, P.M.; Wooden, J.L.

    2005-01-01

    Biogeochemical processes fractionate Ca isotopes in plants and soils along a 4 million year developmental sequence in the Hawaiian Islands. We observed that plants preferentially take up 40Ca relative to 44Ca, and that biological fractionation and changes in the relative contributions from volcanic and marine sources produce a significant increase in 44Ca in soil exchangeable pools. Our results imply moderate fluxes enriched in 44Ca from strongly nutrient-depleted old soils, in contrast with high 40Ca fluxes in young and little weathered environments. In addition, biological fractionation controls divergent geochemical pathways of Ca and Sr in the plant-soil system. While Ca depletes progressively with increasing soil age, Sr/Ca ratios increase systematically. Sr isotope ratios provide a valuable tracer for provenance studies of alkaline earth elements in forested ecosystems, but its usefulness is limited when deciphering biogeochemical processes involved in the terrestrial Ca cycle. Ca isotopes in combination with Sr/ Ca ratios reveal more complex processes involved in the biogeochemistry of Ca and Sr. Copyright 2005 by the American Geophysical Union.

  17. Climate change implications of shifting forest management strategy in a boreal forest ecosystem of Norway.

    PubMed

    Bright, Ryan M; Antón-Fernández, Clara; Astrup, Rasmus; Cherubini, Francesco; Kvalevåg, Maria; Strømman, Anders H

    2014-02-01

    Empirical models alongside remotely sensed and station measured meteorological observations are employed to investigate both the local and global direct climate change impacts of alternative forest management strategies within a boreal ecosystem of eastern Norway. Stand-level analysis is firstly executed to attribute differences in daily, seasonal, and annual mean surface temperatures to differences in surface intrinsic biophysical properties across conifer, deciduous, and clear-cut sites. Relative to a conifer site, a slight local cooling of −0.13 °C at a deciduous site and −0.25 °C at a clear-cut site were observed over a 6-year period, which were mostly attributed to a higher albedo throughout the year. When monthly mean albedo trajectories over the entire managed forest landscape were taken into consideration, we found that strategies promoting natural regeneration of coniferous sites with native deciduous species led to substantial global direct climate cooling benefits relative to those maintaining current silviculture regimes – despite predicted long-term regional warming feedbacks and a reduced albedo in spring and autumn months. The magnitude and duration of the cooling benefit depended largely on whether management strategies jointly promoted an enhanced material supply over business-as-usual levels. Expressed in terms of an equivalent CO2 emission pulse at the start of the simulation, the net climate response at the end of the 21st century spanned −8 to −159 Tg-CO2-eq., depending on whether near-term harvest levels increased or followed current trends, respectively. This magnitude equates to approximately −20 to −300% of Norway's annual domestic (production) emission impact. Our analysis supports the assertion that a carbon-only focus in the design and implementation of forest management policy in boreal and other climatically similar regions can be counterproductive – and at best – suboptimal if boreal forests are to be used as a

  18. A decision framework for identifying models to estimate forest ecosystem services gains from restoration

    USGS Publications Warehouse

    Christin, Zachary; Bagstad, Kenneth J.; Verdone, Michael

    2016-01-01

    Restoring degraded forests and agricultural lands has become a global conservation priority. A growing number of tools can quantify ecosystem service tradeoffs associated with forest restoration. This evolving “tools landscape” presents a dilemma: more tools are available, but selecting appropriate tools has become more challenging. We present a Restoration Ecosystem Service Tool Selector (RESTS) framework that describes key characteristics of 13 ecosystem service assessment tools. Analysts enter information about their decision context, services to be analyzed, and desired outputs. Tools are filtered and presented based on five evaluative criteria: scalability, cost, time requirements, handling of uncertainty, and applicability to benefit-cost analysis. RESTS uses a spreadsheet interface but a web-based interface is planned. Given the rapid evolution of ecosystem services science, RESTS provides an adaptable framework to guide forest restoration decision makers toward tools that can help quantify ecosystem services in support of restoration.

  19. Long-term CO2 enrichment of a forest ecosystem: implications for forest regeneration and succession.

    PubMed

    Mohan, Jacqueline E; Clark, James S; Schlesinger, William H

    2007-06-01

    The composition and successional status of a forest affect carbon storage and net ecosystem productivity, yet it remains unclear whether elevated atmospheric carbon dioxide (CO2) will impact rates and trajectories of forest succession. We examined how CO2 enrichment (+200 microL CO2/L air differential) affects forest succession through growth and survivorship of tree seedlings, as part of the Duke Forest free-air CO2 enrichment (FACE) experiment in North Carolina, USA. We planted 2352 seedlings of 14 species in the low light forest understory and determined effects of elevated CO2 on individual plant growth, survival, and total sample biomass accumulation, an integrator of plant growth and survivorship over time, for six years. We used a hierarchical Bayes framework to accommodate the uncertainty associated with the availability of light and the variability in growth among individual plants. We found that most species did not exhibit strong responses to CO2. Ulmus alata (+21%), Quercus alba (+9.5%), and nitrogen-fixing Robinia pseudoacacia (+230%) exhibited greater mean annual relative growth rates under elevated CO2 than under ambient conditions. The effects of CO2 were small relative to variability within populations; however, some species grew better under low light conditions when exposed to elevated CO2 than they did under ambient conditions. These species include shade-intolerant Liriodendron tulipifera and Liquidambar styraciflua, intermediate-tolerant Quercus velutina, and shade-tolerant Acer barbatum, A. rubrum, Prunus serotina, Ulmus alata, and Cercis canadensis. Contrary to our expectation, shade-intolerant trees did not survive better with CO2 enrichment, and population-scale responses to CO2 were influenced by survival probabilities in low light. CO2 enrichment did not increase rates of sample biomass accumulation for most species, but it did stimulate biomass growth of shade-tolerant taxa, particularly Acer barbatum and Ulmus alata. Our data suggest a

  20. Effects of productivity on biodiversity in forest ecosystems across the United States and China.

    PubMed

    Liang, Jingjing; Watson, James V; Zhou, Mo; Lei, Xiangdong

    2016-04-01

    In the global campaign against biodiversity loss in forest ecosystems, land managers need to know the status of forest biodiversity, but practical guidelines for conserving biodiversity in forest management are lacking. A major obstacle is the incomplete understanding of the relationship between site primary productivity and plant diversity, due to insufficient ecosystem-wide data, especially for taxonomically and structurally diverse forest ecosystems. We investigated the effects of site productivity (the site's inherent capacity to grow timber) on tree species richness across 19 types of forest ecosystems in North America and China through 3 ground-sourced forest inventory data sets (U.S. Forest Inventory and Analysis, Cooperative Alaska Forest Inventory, and Chinese Forest Management Planning Inventory). All forest types conformed to a consistent and highly significant (P < 0.001) hump-shaped unimodal relationship, of which the generalized coefficients of determination averaged 20.5% over all the forest types. That is, tree species richness first increased as productivity increased at a progressively slower rate, and, after reaching a maximum, richness started to decline. Our consistent findings suggest that forests of high productivity would sustain few species because they consist mostly of flat homogeneous areas lacking an environmental gradient along which a diversity of species with different habitats can coexist. The consistency of the productivity-biodiversity relationship among the 3 data sets we examined makes it possible to quantify the expected tree species richness that a forest stand is capable of sustaining, and a comparison between the actual species richness and the sustainable values can be useful in prioritizing conservation efforts. PMID:26954431

  1. Simulation of the effect of air pollution on forest ecosystems in a region

    SciTech Connect

    Tarko, A.M.; Bykadorov, A.V.; Kryuchkov, V.V. ||

    1995-03-01

    This article describes a model of air pollution effects on spruce in forests of the northern taiga regions which have been exposed to air pollution from a large metallurgical industrial complex. Both the predictions the model makes about forest ecosystem degradation zones and the limitations of the model are discussed. 5 refs., 1 fig.

  2. IMPACTS OF AIR POLLUTION AND CLIMATE CHANGE ON FOREST ECOSYSTEMS - EMERGING RESEARCH NEEDS

    EPA Science Inventory

    Outcomes from the 22nd meeting for Specialists in Air Pollution Effects on Forest Ecosystems "Forests under Anthropogenic Pressure - Effects of Air Pollution, Climate Change and Urban Development", September 10-16, 2006, Riverside, CA, USA are summarized. Tropospheric ozone is st...

  3. 77 FR 21721 - Sierra National Forest, Bass Lake Ranger District, California, Whisky Ecosystem Restoration Project

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-11

    ..., Whisky Ecosystem Restoration Project AGENCY: Forest Service, USDA. ACTION: Notice of intent to prepare an... restoration treatments, east of the community of North Fork, California. This would be north of Cascadel Point... Ecosystem Restoration Project (Madera County, California) lies within the Willow Creek watershed,...

  4. Northern Forest DroughtNet: A New Framework to Understand Impacts of Precipitation Change on the Northern Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Asbjornsen, H.; Rustad, L.; Templer, P. H.; Jennings, K.; Phillips, R.; Smith, M.

    2014-12-01

    Recent trends and projections for future change for the U.S. northern forests suggest that the region's climate is becoming warmer, wetter, and, ironically, drier, with more precipitation occurring as large events, separated by longer periods with no precipitation. However, to date, precipitation manipulation experiments conducted in forest ecosystems represent only ~5% of all such experiments worldwide, and our understanding of how the mesic-adapted northern forest will respond to greater frequency and intensity of drought in the future is especially poor. Several important challenges have hampered previous research efforts to conduct forest drought experiments and draw robust conclusions, including difficulties in reducing water uptake by deep and lateral tree roots, logistical and financial constraints to establishing and maintaining large-scale field experiments, and the lack of standardized approaches for determining the appropriate precipitation manipulation treatment (e.g., amount and timing of throughfall displacement), designing and constructing the throughfall displacement infrastructure, identifying key response variables, and collecting and analyzing the field data. The overarching goal of this project is to establish a regional research coordination network - Northern Forest DroughtNet - to investigate the impacts of changes in the amount and distribution of precipitation on the hydrology, biogeochemistry, and carbon (C) cycling dynamics of northern temperate forests. Specific objectives include the development of a standard prototype for conducting precipitation manipulation studies in forest ecosystems (in collaboration with the international DroughtNet-RCN) and the implementation of this prototype drought experiment at the Hubbard Brook Experimental Forest. Here, we present the advances made thus far towards achieving the objectives of Northern Forest DroughtNet, plans for future work, and an invitation to the larger scientific community interested

  5. [Forest ecosystem services and their ecological valuation--a case study of tropical forest in Jianfengling of Hainan Island].

    PubMed

    Xiao, H; Ouyang, Z; Zhao, J; Wang, X

    2000-08-01

    This paper attempts to present forest ecosystem services and their indirect economic value of Jianfengling tropical forest in Hainan Island. The results show that average annual integrated ecosystem service value of Jianfengling tropical forest, which covers 44667.00 hm2, adds up to 664.38 million yuan(Chinese RMB), of which, about 71.64 million yuan is of the output of standing trees and other forest products, about 394.29 million yuan of water-holding, about 2.47 million yuan of soil conservation against erosion, about 13.16 million yuan of carbon fixation for reducing green house effect, about 4.29 million yuan of nutrient retention for N, P, K, Ca and Mg, about 178.53 million yuan of air purification.

  6. Forest management and biodiversity conservation based on natural ecosystem dynamics in northern Europe: the complexity challenge.

    PubMed

    Kuuluvainen, Timo

    2009-09-01

    Recent research in northern Europe has revised many long-held conceptions of the complexity of forest ecosystems and their natural structure and dynamics. The unveiling of the picture of natural characteristics of forest ecosystem structure and dynamics reveals much more diversity than its traditional complement, highlighting the importance of non-stand-replacing disturbances and the associated heterogeneous and dynamic stand and landscape structures. This increasing detail is a reflection of a fundamental change in the ecological understanding of forests as complex ecosystems. In particular, the generalization that the boreal forest is regulated by fierce stand-replacing disturbances, leading to the dominance of even-aged stand successions, has been disproved. However, this misconception has, until now, been repeated and used to legitimize the dominant practice of clear-cutting as a nature-based way to manage the forest. The practical conclusion of this review paper is that the dominating forest management model in North European boreal forests, which is based on the clear-cut harvesting of timber and growing of even-aged stands, is in contradiction with the variable and complex characteristics of the disturbance-succession cycle observed in naturally dynamic forests with negligible human impact. As a consequence, the structural variation of the boreal forest under management has been grossly truncated compared with its natural range. Because of this, and due to the scarcity of protection areas in many regions of northern Europe, it is not likely that the conservation of native biodiversity and ecological sustainability will be attained, assuming that the model of forest management remains unchanged. Thus, there is a strong incentive for change in the prevailing forest management model toward one that is based on natural ecosystem dynamics and an understanding of forests as complex systems. PMID:19860154

  7. Nitrogen Additions Affect Root Dynamics in a Boreal Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Turner, K. M.; Treseder, K. K.

    2004-12-01

    As with many ecosystems, North American boreal forests are increasingly subjected to anthropogenic nitrogen deposition. To examine potential effects on plant growth, we created nitrogen fertilization plots in three sites along an Alaskan fire chronosequence composed of forests aged 5, 17, and 80 years. Each site had been exposed to two years of nitrogen fertilization, with four control plots and four nitrogen plots per site. General observations indicate that aboveground net primary productivity appears to be nitrogen limited in each site. We hypothesized that nitrogen fertilization would positively influence root dynamics as well, with nitrogen additions resulting in an increase in standing root biomass and length. To test our hypothesis, we used a minirhizotron camera to collect sequential images of roots in the top 10 cm of soil in both nitrogen fertilized and control plots in each site. Images were collected monthly during the growing season, with a total of five sampling times between May 2003 and May 2004. We then analyzed the images with WinRhizotron root measurement software. Nitrogen fertilization had varying effects on root biomass among the three sites, with a significant site by N interaction (P = 0.039). A decrease in root biomass was observed in the 5 and 80 year old sites, dropping from 207 g/m2 to 79 g/m2 and from 230 g/m2 to 129 g/m2 for the youngest and oldest sites, respectively. In contrast, root biomass increased from 52 g/m2 to 107 g/m2 in the 17 year old site. (Values are for the top 10 cm of soil only, and likely underestimate total root stocks.) Patterns in standing root lengths diverged from those of root biomass, with a 2.5-fold overall increase under nitrogen fertilization across all sites (P = 0.004). There were no significant differences among sites in nitrogen response. Standing root biomass and length differed from one another in their responses to nitrogen fertilization because nitrogen additions decreased specific root weight (as g

  8. [Effects of CO2 storage flux on carbon budget of forest ecosystem].

    PubMed

    Zhang, Mi; Wen, Xue-fa; Yu, Gui-rui; Zhang, Lei-ming; Fu, Yu-ling; Sun, Xiao-min; Han, Shi-jie

    2010-05-01

    Carbon dioxide (CO2) storage flux in the air space below measurement height of eddy covariance is very important to correctly evaluate net ecosystem exchange of CO2 (NEE) between forest ecosystem and atmosphere. This study analyzed the dynamic variation of CO2 storage flux and its effects on the carbon budget of a temperate broad-leaved Korean pine mixed forest at Changbai Mountains, based on the eddy covariance flux data and the vertical profile of CO2 concentration data. The CO2 storage flux in this forest ecosystem had typical diurnal variation, with the maximum variation appeared during the transition from stable atmospheric layer to unstable atmospheric layer. The CO2 storage flux calculated by the change in CO2 concentration throughout a vertical profile was not significantly different from that calculated by the change in CO2 concentration at the measurement height of eddy covariance. The NEE of this forest ecosystem was underestimated by 25% and 19% at night and at daytime, respectively, without calculating the CO2 storage flux at half-hour scale, and was underestimated by 10% and 25% at daily scale and annual scale, respectively. Without calculating the CO2 storage flux in this forest ecosystem, the parameters of Michaelis-Menten equation and Lloyd-Taylor equation were underestimated, and the ecosystem apparent quantum yield (alpha) and the ecosystem respiration rate (Rref) at the reference temperature were mostly affected. The gross primary productivity (GPP) and ecosystem respiration (Re) of this forest ecosystem were underestimated about 20% without calculating the CO2 storage flux at half-hour, daily scale, and annual scale.

  9. Soil bacterial community structure responses to precipitation reduction and forest management in forest ecosystems across Germany.

    PubMed

    Felsmann, Katja; Baudis, Mathias; Gimbel, Katharina; Kayler, Zachary E; Ellerbrock, Ruth; Bruelheide, Helge; Bruehlheide, Helge; Bruckhoff, Johannes; Welk, Erik; Puhlmann, Heike; Weiler, Markus; Gessler, Arthur; Ulrich, Andreas

    2015-01-01

    Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season. PMID:25875835

  10. Soil Bacterial Community Structure Responses to Precipitation Reduction and Forest Management in Forest Ecosystems across Germany

    PubMed Central

    Felsmann, Katja; Baudis, Mathias; Gimbel, Katharina; Kayler, Zachary E.; Ellerbrock, Ruth; Bruehlheide, Helge; Bruckhoff, Johannes; Welk, Erik; Puhlmann, Heike; Weiler, Markus; Gessler, Arthur; Ulrich, Andreas

    2015-01-01

    Soil microbial communities play an important role in forest ecosystem functioning, but how climate change will affect the community composition and consequently bacterial functions is poorly understood. We assessed the effects of reduced precipitation with the aim of simulating realistic future drought conditions for one growing season on the bacterial community and its relation to soil properties and forest management. We manipulated precipitation in beech and conifer forest plots managed at different levels of intensity in three different regions across Germany. The precipitation reduction decreased soil water content across the growing season by between 2 to 8% depending on plot and region. T-RFLP analysis and pyrosequencing of the 16S rRNA gene were used to study the total soil bacterial community and its active members after six months of precipitation reduction. The effect of reduced precipitation on the total bacterial community structure was negligible while significant effects could be observed for the active bacteria. However, the effect was secondary to the stronger influence of specific soil characteristics across the three regions and management selection of overstorey tree species and their respective understorey vegetation. The impact of reduced precipitation differed between the studied plots; however, we could not determine the particular parameters being able to modify the response of the active bacterial community among plots. We conclude that the moderate drought induced by the precipitation manipulation treatment started to affect the active but not the total bacterial community, which points to an adequate resistance of the soil microbial system over one growing season. PMID:25875835

  11. Growing Season Length as a Key Factor of Cumulative Net Ecosystem Exchange Over the Pine Forest Ecosystems in Europe

    NASA Astrophysics Data System (ADS)

    Danielewska, Alina; Urbaniak, Marek; Olejnik, Janusz

    2015-04-01

    The Scots pine is one of the most important species in European and Asian forests. Due to a widespread occurrence of pine forests, their significance in the energy and mass exchange between the Earth surface and the atmosphere is also important, particularly in the context of climate change and greenhouse gases balance. The aim of this work is to present the relationship between the average annual net ecosystem productivity and growing season length, latitude and air temperature (tay) over Europe. Therefore, CO2 flux measurement data from eight European pine dominated forests were used. The observations suggest that there is a correlation between the intensity of CO2 uptake or emission by a forest stand and the above mentioned parameters. Based on the obtained results, all of the selected pine forest stands were CO2 sinks, except a site in northern Finland. The carbon dioxide uptake increased proportionally with the increase of growing season length (9.212 g C m-2 y-1 per day of growing season, R2 = 0.53, p = 0.0399). This dependency showed stronger correlation and higher statistical significance than both relationships between annual net ecosystem productivity and air temperature (R2 = 0.39, p = 0.096) and annual net ecosystem productivity and latitude (R2 = 0.47, p = 0.058). The CO2 emission surpassed assimilation in winter, early spring and late autumn. Moreover, the appearance of late, cold spring and early winter, reduced annual net ecosystem productivity. Therefore, the growing season length can be considered as one of the main factor affecting the annual carbon budget of pine forests.

  12. Temporal-Spatial Pattern of Carbon Stocks in Forest Ecosystems in Shaanxi, Northwest China.

    PubMed

    Cui, Gaoyang; Chen, Yunming; Cao, Yang

    2015-01-01

    The precise and accurate quantitative evaluation of the temporal and spatial pattern of carbon (C) storage in forest ecosystems is critical for understanding the role of forests in the global terrestrial C cycle and is essential for formulating forest management policies to combat climate change. In this study, we examined the C dynamics of forest ecosystems in Shaanxi, northwest China, based on four forest inventories (1989-1993, 1994-1998, 1999-2003, and 2004-2008) and field-sampling measurements (2012). The results indicate that the total C storage of forest ecosystems in Shaanxi increased by approximately 29.3%, from 611.72 Tg in 1993 to 790.75 Tg in 2008, partially as a result of ecological restoration projects. The spatial pattern of C storage in forest ecosystems mainly exhibited a latitude-zonal distribution across the province, increasing from north (high latitude) to south (low latitude) generally, which signifies the effect of environmental conditions, chiefly water and heat related factors, on forest growth and C sequestration. In addition, different data sources and estimation methods had a significant effect on the results obtained, with the C stocks in 2008 being considerably overestimated (864.55 Tg) and slightly underestimated (778.07 Tg) when measured using the mean C density method and integrated method, respectively. Overall, our results demonstrated that the forest ecosystem in Shaanxi acted as a C sink over the last few decades. However, further studies should be carried out with a focus on adaption of plants to environmental factors along with forest management for vegetation restoration to maximize the C sequestration potential and to better cope with climate change. PMID:26353011

  13. Temporal-Spatial Pattern of Carbon Stocks in Forest Ecosystems in Shaanxi, Northwest China

    PubMed Central

    Cui, Gaoyang; Chen, Yunming; Cao, Yang

    2015-01-01

    The precise and accurate quantitative evaluation of the temporal and spatial pattern of carbon (C) storage in forest ecosystems is critical for understanding the role of forests in the global terrestrial C cycle and is essential for formulating forest management policies to combat climate change. In this study, we examined the C dynamics of forest ecosystems in Shaanxi, northwest China, based on four forest inventories (1989–1993, 1994–1998, 1999–2003, and 2004–2008) and field-sampling measurements (2012). The results indicate that the total C storage of forest ecosystems in Shaanxi increased by approximately 29.3%, from 611.72 Tg in 1993 to 790.75 Tg in 2008, partially as a result of ecological restoration projects. The spatial pattern of C storage in forest ecosystems mainly exhibited a latitude-zonal distribution across the province, increasing from north (high latitude) to south (low latitude) generally, which signifies the effect of environmental conditions, chiefly water and heat related factors, on forest growth and C sequestration. In addition, different data sources and estimation methods had a significant effect on the results obtained, with the C stocks in 2008 being considerably overestimated (864.55 Tg) and slightly underestimated (778.07 Tg) when measured using the mean C density method and integrated method, respectively. Overall, our results demonstrated that the forest ecosystem in Shaanxi acted as a C sink over the last few decades. However, further studies should be carried out with a focus on adaption of plants to environmental factors along with forest management for vegetation restoration to maximize the C sequestration potential and to better cope with climate change. PMID:26353011

  14. Theory into practice: implementing ecosystem management objectives in the USDA Forest Service.

    PubMed

    Butler, Kelly F; Koontz, Tomas M

    2005-02-01

    In the United States and around the world, scientists and practitioners have debated the definition and merits of ecosystem management as a new approach to natural resource management. While these debates continue, a growing number of organizations formally have adopted ecosystem management. However, adoption does not necessarily lead to successful implementation, and theories are not always put into practice. In this article, we examine how a leading natural resource agency, the United States Department of Agriculture Forest Service, has translated ecosystem management theory into concrete policy objectives and how successfully these objectives are perceived to be implemented throughout the national forest system. Through document analysis, interviews, and survey responses from 345 Forest Service managers (district rangers, forest supervisors, and regional foresters), we find that the agency has incorporated numerous ecosystem management components into its objectives. Agency managers perceive that the greatest attainment of such objectives is related to collaborative stewardship and integration of scientific information, areas in which the organization has considerable prior experience. The objectives perceived to be least attained are adaptive management and integration of social and economic information, areas requiring substantial new resources and a knowledge base not traditionally emphasized by natural resource managers. Overall, success in implementing ecosystem management objectives is linked to committed forest managers.

  15. Coupling of soil prokaryotic diversity and plant diversity across latitudinal forest ecosystems

    PubMed Central

    Wang, Jun-Tao; Zheng, Yuan-Ming; Hu, Hang-Wei; Li, Jing; Zhang, Li-Mei; Chen, Bao-Dong; Chen, Wei-Ping; He, Ji-Zheng

    2016-01-01

    The belowground soil prokaryotic community plays a cardinal role in sustaining the stability and functions of forest ecosystems. Yet, the nature of how soil prokaryotic diversity co-varies with aboveground plant diversity along a latitudinal gradient remains elusive. By establishing three hundred 400-m2 quadrats from tropical rainforest to boreal forest in a large-scale parallel study on both belowground soil prokaryote and aboveground tree and herb communities, we found that soil prokaryotic diversity couples with the diversity of herbs rather than trees. The diversity of prokaryotes and herbs responds similarly to environmental factors along the latitudinal gradient. These findings revealed that herbs provide a good predictor of belowground biodiversity in forest ecosystems, and provide new perspective on the aboveground and belowground interactions in forest ecosystems. PMID:26781165

  16. Coupling of soil prokaryotic diversity and plant diversity across latitudinal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Wang, Jun-Tao; Zheng, Yuan-Ming; Hu, Hang-Wei; Li, Jing; Zhang, Li-Mei; Chen, Bao-Dong; Chen, Wei-Ping; He, Ji-Zheng

    2016-01-01

    The belowground soil prokaryotic community plays a cardinal role in sustaining the stability and functions of forest ecosystems. Yet, the nature of how soil prokaryotic diversity co-varies with aboveground plant diversity along a latitudinal gradient remains elusive. By establishing three hundred 400-m2 quadrats from tropical rainforest to boreal forest in a large-scale parallel study on both belowground soil prokaryote and aboveground tree and herb communities, we found that soil prokaryotic diversity couples with the diversity of herbs rather than trees. The diversity of prokaryotes and herbs responds similarly to environmental factors along the latitudinal gradient. These findings revealed that herbs provide a good predictor of belowground biodiversity in forest ecosystems, and provide new perspective on the aboveground and belowground interactions in forest ecosystems.

  17. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    PubMed

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-01-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning. PMID:25766381

  18. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China.

    PubMed

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C; Sang, Weiguo

    2015-03-13

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  19. Asymmetric warming significantly affects net primary production, but not ecosystem carbon balances of forest and grassland ecosystems in northern China

    NASA Astrophysics Data System (ADS)

    Su, Hongxin; Feng, Jinchao; Axmacher, Jan C.; Sang, Weiguo

    2015-03-01

    We combine the process-based ecosystem model (Biome-BGC) with climate change-scenarios based on both RegCM3 model outputs and historic observed trends to quantify differential effects of symmetric and asymmetric warming on ecosystem net primary productivity (NPP), heterotrophic respiration (Rh) and net ecosystem productivity (NEP) of six ecosystem types representing different climatic zones of northern China. Analysis of covariance shows that NPP is significant greater at most ecosystems under the various environmental change scenarios once temperature asymmetries are taken into consideration. However, these differences do not lead to significant differences in NEP, which indicates that asymmetry in climate change does not result in significant alterations of the overall carbon balance in the dominating forest or grassland ecosystems. Overall, NPP, Rh and NEP are regulated by highly interrelated effects of increases in temperature and atmospheric CO2 concentrations and precipitation changes, while the magnitude of these effects strongly varies across the six sites. Further studies underpinned by suitable experiments are nonetheless required to further improve the performance of ecosystem models and confirm the validity of these model predictions. This is crucial for a sound understanding of the mechanisms controlling the variability in asymmetric warming effects on ecosystem structure and functioning.

  20. Nutrient addition effects on tropical dry forests: a mini-review from microbial to ecosystem scales

    NASA Astrophysics Data System (ADS)

    Powers, Jennifer; Becklund, Kristen; Gei, Maria; Iyengar, Siddarth; Meyer, Rebecca; O'Connell, Christine; Schilling, Erik; Smith, Christina; Waring, Bonnie; Werden, Leland

    2015-06-01

    Humans have more than doubled inputs of reactive nitrogen globally and greatly accelerated the biogeochemical cycles of phosphorus and metals. However, the impacts of increased element mobility on tropical ecosystems remain poorly quantified, particularly for the vast tropical dry forest biome. Tropical dry forests are characterized by marked seasonality, relatively little precipitation, and high heterogeneity in plant functional diversity and soil chemistry. For these reasons, increased nutrient deposition may affect tropical dry forests differently than wet tropical or temperate forests. Here we review studies that investigated how nutrient availability affects ecosystem and community processes from the microsite to ecosystem scales in tropical dry forests. The effects of N and P addition on ecosystem carbon cycling and plant and microbial dynamics depend on forest successional stage, soil parent material and rainfall regime. Responses may depend on whether overall productivity is N- versus P-limited, although data to test this hypothesis are limited. These results highlight the many important gaps in our understanding of tropical dry forest responses to global change. Large-scale experiments are required to resolve these uncertainties.

  1. Foliar litter decomposition in an alpine forest meta-ecosystem on the eastern Tibetan Plateau.

    PubMed

    Yue, Kai; Yang, Wanqin; Peng, Changhui; Peng, Yan; Zhang, Chuan; Huang, Chunping; Tan, Yu; Wu, Fuzhong

    2016-10-01

    Litter decomposition is a biological process fundamental to element cycling and a main nutrient source within forest meta-ecosystems, but few studies have looked into this process simultaneously in individual ecosystems, where environmental factors can vary substantially. A two-year field study conducted in an alpine forest meta-ecosystem with four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana) that varied widely in chemical traits showed that both litter species and ecosystem type (i.e., forest floor, stream and riparian zone) are important factors affecting litter decomposition, and their effects can be moderated by local-scale environmental factors such as temperature and nutrient availability. Litter decomposed fastest in the streams followed by the riparian zone and forest floor regardless of species. For a given litter species, both the k value and limit value varied significantly among ecosystems, indicating that the litter decomposition rate and extent (i.e., reaching a limit value) can be substantially affected by ecosystem type and the local-scale environmental factors. Apart from litter initial acid unhydrolyzable residue (AUR) concentration and its ratio to nitrogen concentration (i.e., AUR/N ratio), the initial nutrient concentrations of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) were also important litter traits that affected decomposition depending on the ecosystem type. PMID:27220105

  2. Foliar litter decomposition in an alpine forest meta-ecosystem on the eastern Tibetan Plateau.

    PubMed

    Yue, Kai; Yang, Wanqin; Peng, Changhui; Peng, Yan; Zhang, Chuan; Huang, Chunping; Tan, Yu; Wu, Fuzhong

    2016-10-01

    Litter decomposition is a biological process fundamental to element cycling and a main nutrient source within forest meta-ecosystems, but few studies have looked into this process simultaneously in individual ecosystems, where environmental factors can vary substantially. A two-year field study conducted in an alpine forest meta-ecosystem with four litter species (i.e., willow: Salix paraplesia, azalea: Rhododendron lapponicum, cypress: Sabina saltuaria, and larch: Larix mastersiana) that varied widely in chemical traits showed that both litter species and ecosystem type (i.e., forest floor, stream and riparian zone) are important factors affecting litter decomposition, and their effects can be moderated by local-scale environmental factors such as temperature and nutrient availability. Litter decomposed fastest in the streams followed by the riparian zone and forest floor regardless of species. For a given litter species, both the k value and limit value varied significantly among ecosystems, indicating that the litter decomposition rate and extent (i.e., reaching a limit value) can be substantially affected by ecosystem type and the local-scale environmental factors. Apart from litter initial acid unhydrolyzable residue (AUR) concentration and its ratio to nitrogen concentration (i.e., AUR/N ratio), the initial nutrient concentrations of phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) were also important litter traits that affected decomposition depending on the ecosystem type.

  3. Ecosystem carbon dioxide fluxes after disturbance in forests of North America

    NASA Astrophysics Data System (ADS)

    Amiro, B. D.; Barr, A. G.; Barr, J. G.; Black, T. A.; Bracho, R.; Brown, M.; Chen, J.; Clark, K. L.; Davis, K. J.; Desai, A. R.; Dore, S.; Engel, V.; Fuentes, J. D.; Goldstein, A. H.; Goulden, M. L.; Kolb, T. E.; Lavigne, M. B.; Law, B. E.; Margolis, H. A.; Martin, T.; McCaughey, J. H.; Misson, L.; Montes-Helu, M.; Noormets, A.; Randerson, J. T.; Starr, G.; Xiao, J.

    2010-12-01

    Disturbances are important for renewal of North American forests. Here we summarize more than 180 site years of eddy covariance measurements of carbon dioxide flux made at forest chronosequences in North America. The disturbances included stand-replacing fire (Alaska, Arizona, Manitoba, and Saskatchewan) and harvest (British Columbia, Florida, New Brunswick, Oregon, Quebec, Saskatchewan, and Wisconsin) events, insect infestations (gypsy moth, forest tent caterpillar, and mountain pine beetle), Hurricane Wilma, and silvicultural thinning (Arizona, California, and New Brunswick). Net ecosystem production (NEP) showed a carbon loss from all ecosystems following a stand-replacing disturbance, becoming a carbon sink by 20 years for all ecosystems and by 10 years for most. Maximum carbon losses following disturbance (g C m-2y-1) ranged from 1270 in Florida to 200 in boreal ecosystems. Similarly, for forests less than 100 years old, maximum uptake (g C m-2y-1) was 1180 in Florida mangroves and 210 in boreal ecosystems. More temperate forests had intermediate fluxes. Boreal ecosystems were relatively time invariant after 20 years, whereas western ecosystems tended to increase in carbon gain over time. This was driven mostly by gross photosynthetic production (GPP) because total ecosystem respiration (ER) and heterotrophic respiration were relatively invariant with age. GPP/ER was as low as 0.2 immediately following stand-replacing disturbance reaching a constant value of 1.2 after 20 years. NEP following insect defoliations and silvicultural thinning showed lesser changes than stand-replacing events, with decreases in the year of disturbance followed by rapid recovery. NEP decreased in a mangrove ecosystem following Hurricane Wilma because of a decrease in GPP and an increase in ER.

  4. Ecosystem carbon dioxide fluxes after disturbance in forests of North America

    NASA Astrophysics Data System (ADS)

    Amiro, B. D.; Barr, A. G.; Barr, J. G.; Black, T. A.; Bracho, R.; Brown, M.; Chen, J.; Clark, K. L.; Davis, K. J.; Desai, A. R.; Dore, S.; Engel, V.; Fuentes, J. D.; Goldstein, A. H.; Goulden, M. L.; Kolb, T. E.; Lavigne, M. B.; Law, B. E.; Margolis, H. A.; Martin, T.; McCaughey, J. H.; Misson, L.; Montes-Helu, M.; Noormets, A.; Randerson, J. T.; Starr, G.; Xiao, J.

    2010-10-01

    Disturbances are important for renewal of North American forests. Here we summarize more than 180 site years of eddy covariance measurements of carbon dioxide flux made at forest chronosequences in North America. The disturbances included stand-replacing fire (Alaska, Arizona, Manitoba, and Saskatchewan) and harvest (British Columbia, Florida, New Brunswick, Oregon, Quebec, Saskatchewan, and Wisconsin) events, insect infestations (gypsy moth, forest tent caterpillar, and mountain pine beetle), Hurricane Wilma, and silvicultural thinning (Arizona, California, and New Brunswick). Net ecosystem production (NEP) showed a carbon loss from all ecosystems following a stand-replacing disturbance, becoming a carbon sink by 20 years for all ecosystems and by 10 years for most. Maximum carbon losses following disturbance (g C m-2y-1) ranged from 1270 in Florida to 200 in boreal ecosystems. Similarly, for forests less than 100 years old, maximum uptake (g C m-2y-1) was 1180 in Florida mangroves and 210 in boreal ecosystems. More temperate forests had intermediate fluxes. Boreal ecosystems were relatively time invariant after 20 years, whereas western ecosystems tended to increase in carbon gain over time. This was driven mostly by gross photosynthetic production (GPP) because total ecosystem respiration (ER) and heterotrophic respiration were relatively invariant with age. GPP/ER was as low as 0.2 immediately following stand-replacing disturbance reaching a constant value of 1.2 after 20 years. NEP following insect defoliations and silvicultural thinning showed lesser changes than stand-replacing events, with decreases in the year of disturbance followed by rapid recovery. NEP decreased in a mangrove ecosystem following Hurricane Wilma because of a decrease in GPP and an increase in ER.

  5. Characterization of Canopy Layering in Forested Ecosystems Using Full Waveform Lidar

    NASA Technical Reports Server (NTRS)

    Whitehurst, Amanda S.; Swatantran, Anu; Blair, J. Bryan; Hofton, Michelle A.; Dubayah, Ralph

    2013-01-01

    Canopy structure, the vertical distribution of canopy material, is an important element of forest ecosystem dynamics and habitat preference. Although vertical stratification, or "canopy layering," is a basic characterization of canopy structure for research and forest management, it is difficult to quantify at landscape scales. In this paper we describe canopy structure and develop methodologies to map forest vertical stratification in a mixed temperate forest using full-waveform lidar. Two definitions-one categorical and one continuous-are used to map canopy layering over Hubbard Brook Experimental Forest, New Hampshire with lidar data collected in 2009 by NASA's Laser Vegetation Imaging Sensor (LVIS). The two resulting canopy layering datasets describe variation of canopy layering throughout the forest and show that layering varies with terrain elevation and canopy height. This information should provide increased understanding of vertical structure variability and aid habitat characterization and other forest management activities.

  6. Comparative behavior of three long-lived radionuclides in forest ecosystems

    SciTech Connect

    Auerbach, S.I.

    1986-01-01

    This paper deals with studies in three forest ecosystems in eastern Tennessee, an area of rich temperate deciduous forests, sometimes referred to as mixed mesophytic forests. Two of these forest ecosystems were contaminated as a result of waste disposal operations. The third was experimentally tagged with millicurie quantities of /sup 137/Cs. One of these ecosystems is a floodplain forest that is typical of this region. This forest has been growing on alluvial soils since 1944. Prior to that time the area was a temporary holding pond within White Oak Creek which received radioactive effluents from ORNL. Radiocesium was deposited in the pond sediments as were /sup 90/Sr, /sup 239/Pu, /sup 241/Am, and other radionuclides. The dam which created the pond failed in late 1944, and the area was allowed to revert to natural conditions. The result was the development of a floodplain forest consisting of three different forest communities. The soils are fertile alluvials representative of bottomlands. The overstory tree species are principally ash, sycamore, boxelder, willow, and sweetgum (Fraxinus americana L., Plantanus occidentalis L., Acer negundo L., Salix nigra Marsh, and Liquidambar styraciflua L., respectively).

  7. Current net ecosystem exchange of CO2 in a young mixed forest: any heritage from the previous ecosystem?

    NASA Astrophysics Data System (ADS)

    Violette, Aurélie; Heinesch, Bernard; Erpicum, Michel; Carnol, Monique; Aubinet, Marc; François, Louis

    2013-04-01

    For 15 years, networks of flux towers have been developed to determine accurate carbon balance with the eddy-covariance method and determine if forests are sink or source of carbon. However, for prediction of the evolution of carbon cycle and climate, major uncertainties remain on the ecosystem respiration (Reco, which includes the respiration of above ground part of trees, roots respiration and mineralization of the soil organic matter), the gross primary productivity (GPP) and their difference, the net ecosystem exchange (NEE) of forests. These uncertainties are consequences of spatial and inter-annual variability, driven by previous and current climatic conditions, as well as by the particular history of the site (management, diseases, etc.). In this study we focus on the carbon cycle in two mixed forests in the Belgian Ardennes. The first site, Vielsalm, is a mature stand mostly composed of beeches (Fagus sylvatica) and douglas fir (Pseudotsuga menziesii) from 80 to 100 years old. The second site, La Robinette, was covered before 1995 with spruces. After an important windfall and a clear cutting, the site was replanted, between 1995 and 2000, with spruces (Piceas abies) and deciduous species (mostly Betula pendula, Aulnus glutinosa and Salix aurita). The challenge here is to highlight how initial conditions can influence the current behavior of the carbon cycle in a growing stand compared to a mature one, where initial conditions are supposed to be forgotten. A modeling approach suits particularly well for sensitivity tests and estimation of the temporal lag between an event and the ecosystem response. We use the forest ecosystem model ASPECTS (Rasse et al., Ecological Modelling 141, 35-52, 2001). This model predicts long-term forest growth by calculating, over time, hourly NEE. It was developed and already validated on the Vielsalm forest. Modelling results are confronted to eddy-covariance data on both sites from 2006 to 2011. The main difference between both

  8. FOREST SOIL CARBON SEQUESTRATION: ACCOUNTING FOR THIS VITAL ECOSYSTEM SERVICE

    EPA Science Inventory

    Forests play a crucial role in supplying many goods and services that society depends upon on a daily basis including water supply, production of oxygen, soil protection, building materials, wildlife habitat and recreation. Forests also provide a significant amount of carbon seq...

  9. Nutrient loss accelerated by clear-cutting of a forest ecosystem

    USGS Publications Warehouse

    Bormann, F.H.; Likens, G.E.; Fisher, D.W.; Pierce, R.S.

    1968-01-01

    The forest of a small watershed-ecosystem was cut in order to determine the effects of removal of vegetation on nutrient cycles. Relative to undisturbed ecosystems, the cut ecosystem exhibited accelerated loss of nutrients: nitrogen lost during the first year after cutting was equivalent to the amount annually turned over in an undisturbed system, and losses of cations were 3 to 20 times greater than from comparable undisturbed systems. Possible causes of the pattern of nutrient loss from the cut ecosystem are discussed.

  10. Characterization of the Montane Huntington Wildlife Forest Ecosystem Using Machine Learning Approaches from Remote Sensing Data

    NASA Astrophysics Data System (ADS)

    Li, Manqi

    Montane forests are susceptible to various stressors such as land use and climate change. Consequently, research on characterizing montane forest ecosystems should be conducted on a continuous basis for sustainable forest management. In this research, forest type mapping and change analysis, and biomass/carbon stock quantification were performed over a mountainous forest located in the central Adirondack Park, NY, by employing machine learning techniques at the plot level. Multi-temporal Landsat TM data were used to classify forest type cover and to detect forest cover changes for the past 20 years. Forest biomass and carbon stock quantification was then performed using full waveform LiDAR data collected in September 2011. Accuracies from the two case studies were in support of the versatility of machine learning approaches for forest and ecological investigation. Topographic characteristics affected the classification accuracy as well as the forest type change for the past 20 years. LiDAR-derived metrics, especially height-based ones, proved useful for quantifying biomass/carbon stock. Keywords: Landsat TM, full waveform LiDAR, forest classification, forest change analysis, biomass, carbon stock, machine learning

  11. High carbon dioxide uptake by subtropical forest ecosystems in the East Asian monsoon region

    PubMed Central

    Yu, Guirui; Chen, Zhi; Piao, Shilong; Peng, Changhui; Ciais, Philippe; Wang, Qiufeng; Li, Xuanran; Zhu, Xianjin

    2014-01-01

    Temperate- and high-latitude forests have been shown to contribute a carbon sink in the Northern Hemisphere, but fewer studies have addressed the carbon balance of the subtropical forests. In the present study, we integrated eddy covariance observations established in the 1990s and 2000s to show that East Asian monsoon subtropical forests between 20°N and 40°N represent an average net ecosystem productivity (NEP) of 362 ± 39 g C m−2 yr−1 (mean ± 1 SE). This average forest NEP value is higher than that of Asian tropical and temperate forests and is also higher than that of forests at the same latitudes in Europe–Africa and North America. East Asian monsoon subtropical forests have comparable NEP to that of subtropical forests of the southeastern United States and intensively managed Western European forests. The total NEP of East Asian monsoon subtropical forests was estimated to be 0.72 ± 0.08 Pg C yr−1, which accounts for 8% of the global forest NEP. This result indicates that the role of subtropical forests in the current global carbon cycle cannot be ignored and that the regional distributions of the Northern Hemisphere's terrestrial carbon sinks are needed to be reevaluated. The young stand ages and high nitrogen deposition, coupled with sufficient and synchronous water and heat availability, may be the primary reasons for the high NEP of this region, and further studies are needed to quantify the contribution of each underlying factor. PMID:24639529

  12. An inventory-based carbon budget for forest and woodland ecosystems of Turkey.

    PubMed

    Evrendilek, Fatih

    2004-01-01

    Environmental monitoring of national-level comparisons of CO(2) emissions is needed to quantify sources and sinks of carbon (C) in national ecosystems. In this study, a national forest inventory database was used to estimate the past and current pools and fluxes of C in deciduous and coniferous forest and woodland ecosystems (20.7 x 10(6) ha) of Turkey. Growing C stock was 12.63 t C ha(-1) in 1960 and 16.55 t C ha(-1) in 1995. Total C store in the whole live woody biomass was estimated at 22.77 t C ha(-1) in 1996. The total flux of C from the atmosphere into the forest and woodland ecosystems driven by primary productivity was about 1.46 t C ha(-1)(or 30.2 Mt C) in 1996. The estimated net release of C from the forest and woodland ecosystems of Turkey to the atmosphere was about 1.34 t C ha(-1)(or 21.5 Mt C) in 1996. When C released was taken into account, net ecosystem sequestration (NES) resulted in 0.12 t C ha(-1) per year. Such analytical tools as national forest C budgets are needed to improve our preventive and mitigative strategies for dealing with global climate change.

  13. Monoterpene Compositions of Three Forested Ecosystems in the Central Amazon Basin

    NASA Astrophysics Data System (ADS)

    Jardine, A.; Fuentes, J. D.; Manzi, A. O.; Higuchi, N.; Chambers, J. Q.; Jardine, K.

    2014-12-01

    Monoterpenes play fundamental roles as secondary metabolites in forested ecosystems and as gas and liquid phase secondary organic aerosol (SOA) precursors in their surrounding atmospheres. While the chemical pathways involved in ozonolysis driven SOA formation from individual monoterpene precursors is known, local and regional chemical transport models are still lacking observations of speciated monoterpenes from forested atmospheres. Here, we present high vertically resolved mixing ratio profiles of speciated monoterpenes from the ambient air of three neighboring forested ecosystems in the central Amazon Basin. Two well-drained plateau primary forests and one seasonally flooded valley forest were sampled during the afternoon hours (13:00 - 16:30) on walkup towers from the initiation of the 2013-14 wet season through the onset of the 2014 dry season (Nov 2013 - Jul 2014). Ambient mixing ratios in all three ecosystems were greatest in the upper canopy with secondary sources of some monoterpenes within the sub-canopies. Relative vertical compositions of monoterpenes did not change significantly throughout the seasons for either ecosystem type. Both ecosystem types were dominated by d-limonene (up to 1.6 ppb) with equally strong mixing ratios of alpha-pinene in the valley compared to the much weaker a-pinene mixing ratios on the plateaus (up to 200 ppt). The highly reactive cis- and trans-beta-ocimene were consistently present in both ecosystems (up to 250 ppt) with the addition of equally high camphene mixing ratios in the valley forest (up to 200 ppt) which is present in the plateau ecosystems in low quantities (50 ppt). With respect to clean atmosphere mixing ratios of 10 ppb ozone, lifetimes are below 2 hours for camphene and below 30 minutes for ocimene, suggesting a potentially large impact on local and possibly regional ozonolysis and subsequent SOA composition.

  14. Studies on Interpretive Structural Model for Forest Ecosystem Management Decision-Making

    NASA Astrophysics Data System (ADS)

    Liu, Suqing; Gao, Xiumei; Zen, Qunying; Zhou, Yuanman; Huang, Yuequn; Han, Weidong; Li, Linfeng; Li, Jiping; Pu, Yingshan

    Characterized by their openness, complexity and large scale, forest ecosystems interweave themselves with social system, economic system and other natural ecosystems, thus complicating both their researches and management decision-making. According to the theories of sustainable development, hierarchy-competence levels, cybernetics and feedback, 25 factors have been chosen from human society, economy and nature that affect forest ecosystem management so that they are systematically analyzed via developing an interpretive structural model (ISM) to reveal their relationships and positions in the forest ecosystem management. The ISM consists of 7 layers with the 3 objectives for ecosystem management being the top layer (the seventh layer). The ratio between agricultural production value and industrial production value as the bases of management decision-making in forest ecosystems becomes the first layer at the bottom because it has great impacts on the values of society and the development trends of forestry, while the factors of climatic environments, intensive management extent, management measures, input-output ratio as well as landscape and productivity are arranged from the second to sixth layers respectively.

  15. Radiocesium distributions and fluxes in the forest ecosystems of Chernobyl and Fukushima

    NASA Astrophysics Data System (ADS)

    Yoschenko, Vasyl; Nanba, Kenji; Konoplev, Alexei; Takase, Tsugiko; Kashparov, Valery; Zheleznyak, Mark

    2015-04-01

    Institute of Environmental Radioactivity (IER) of Fukushima University and Ukrainian Institute of Agricultural Radiology (UIAR) of NUBiP of Ukraine have started the long-term monitoring programs for characterization of the radiocesium distributions and fluxes in the typical forest ecosystems of the Fukushima and Chernobyl zones, respectively. Realization of the programs will enable identification of the key processes governing the radionuclides cycling in the forest ecosystems at the intermediate (Fukushima) and late (Chernobyl) stages of the two accidents and will provide the empirical data needed for modelling the radionuclide long-term behavior in the Fukushima and Chernobyl forests. At the present stage in the Chernobyl zone root uptake of radionuclides plays the main role in the forest biomass contamination with 137Cs. In the typical Scots pine forests its inventories in the aboveground biomass and litter may reach several percents of the total radionuclide activity in the ecosystem. The radionuclides biogenic fluxes (root uptake and return to soil with litterfall and throughfall) in the Chernobyl forests are comparable or exceed their geochemical migration fluxes in the root-inhabited soil layer, which leads to stabilization of the radionuclide distributions in the soil profile and to the gradual decrease of the apparent vertical migration rates. For example, the main part (about 80%) of the radiocesium activity in soil is still localized in the 0-5 cm topsoil layer; the radiocesium uptake flux may reach 0.n % year-1 of its total activity in the ecosystem, while the geochemical migration flux from the root-inhabited layer is estimated as 0.1 % year-1. In the studied typical forest ecosystem at the territory contaminated as a result of the Fukushima accident (Sugi forest) about 20% of the total radiocesium activity in the soil profile is localized in the forest litter, and similarly to the Chernobyl forest, major part of the activity, about 70% of the total in

  16. Interactive effects between N addition and disturbance on boreal forest ecosystem structure and function

    NASA Astrophysics Data System (ADS)

    Nordin, Annika; Strengbom, Joachim; From, Fredrik

    2014-05-01

    In management of boreal forests, nitrogen (N) enrichment from atmospheric deposition or from forest fertilization can appear in combination with land-use related disturbances, i.e. tree harvesting by clear-felling. Long-term interactive effects between N enrichment and disturbance on boreal forest ecosystem structure and function are, however, poorly known. We investigated effects of N enrichment by forest fertilization done > 25 years ago on forest understory species composition in old-growth (undisturbed) forests, and in forests clear-felled 10 years ago (disturbed). In clear-felled forests we also investigated effects of the previous N addition on growth of tree saplings. The results show that the N enrichment effect on the understory species composition was strongly dependent on the disturbance caused by clear-felling. In undisturbed forests, there were small or no effects on understory species composition from N addition. In contrast, effects were large in forests first exposed to N addition and subsequently disturbed by clear-felling. Effects of N addition differed among functional groups of plants. Abundance of graminoids increased (+232%) and abundance of dwarf shrubs decreased (-44%) following disturbance in N fertilized forests. For vascular plants, the two perturbations had contrasting effects on α-(within forests) and β-diversity (among forests): in disturbed forests, N addition reduced, or had no effect on α-diversity, while β-diversity increased. For bryophytes, negative effects of disturbance on α-diversity were smaller in N fertilized forests than in forests not fertilized, while neither N addition nor disturbance had any effects on β-diversity. Moreover, sapling growth in forests clear-felled 10 years ago was significantly higher in previously N fertilized forests than in forests not fertilized. Our study show that effects of N addition on plant communities may appear small, short-lived, or even absent until exposed to a disturbance. This

  17. How does wind-throw disturbance affect the carbon budget of an upland spruce forest ecosystem?

    NASA Astrophysics Data System (ADS)

    Lindauer, Matthias; Schmid, Hans Peter; Grote, Rüdiger; Mauder, Matthias; Wolpert, Benjamin; Steinbrecher, Rainer

    2014-05-01

    Forests, especially in mid-latitudes are generally designated as large carbon sinks. However, stand-replacing disturbance events like fires, insect-infestations, or severe wind-storms can shift an ecosystem from carbon sink to carbon source within short time and keep it as this for a long time. In Addition, extreme weather situations which promote the occurrence of ecosystem disturbances are likely to increase in the future due to climate change. The development and competition of different vegetation types (spruce vs. grass) as well as soil organic matter (SOM), and their contribution to the net ecosystem exchange (NEE), in such disturbed forest ecosystems are largely unknown. In a large wind-throw area (ca. 600 m diameter, due to cyclone Kyrill in January 2007) within a mature upland spruce forest, where dead-wood has not been removed, in the Bavarian Forest National Park (Lackenberg, 1308 m a.s.l., Bavaria, Germany), fluxes of CO2, water vapor and energy have been measured with the Eddy Covariance (EC) method since 2009. Model simulations (MoBiLE) were used to estimate the GPP components from trees and grassland as well as to differentiate between soil and plant respiration, and to get an idea about the long term behavior of the ecosystems carbon exchange. For 2009, 2010, 2011, 2012, and 2013 estimates of annual Net Ecosystem Exchange (NEE) showed that the wind-throw was a marked carbon source. However, the few remaining trees and newly emerging vegetation (grass, sparse young spruce, etc.) lead to an already strong Gross Ecosystem Production (GEP). Model simulations conformed well with the measurements. To our knowledge, we present the worldwide first long-term measurements of NEE within a non-cleared wind-throw-disturbed forest ecosystem.

  18. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes.

    PubMed

    Wood, Tana E; Cavaleri, Molly A; Reed, Sasha C

    2012-11-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO(2) ) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  19. Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes

    USGS Publications Warehouse

    Wood, Tana E.; Cavaleri, Molly A.; Reed, Sasha C.

    2012-01-01

    Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant climatic change. Here we present a contemporary synthesis of the existing data and what they suggest about how tropical forests will respond to increasing temperatures. Our goals were to: (i) determine whether there is enough evidence to support the conclusion that increased temperature will affect tropical forest C balance; (ii) if there is sufficient evidence, determine what direction this effect will take; and, (iii) establish what steps should to be taken to resolve the uncertainties surrounding tropical forest responses to increasing temperatures. We approach these questions from a mass-balance perspective and therefore focus primarily on the effects of temperature on inputs and outputs of C, spanning microbial- to ecosystem-scale responses. We found that, while there is the strong potential for temperature to affect processes related to C cycling and storage in tropical forests, a notable lack of data combined with the physical, biological and chemical diversity of the forests themselves make it difficult to resolve this issue with certainty. We suggest a variety of experimental approaches that could help elucidate how tropical forests will respond to warming, including large-scale in situ manipulation experiments, longer term field experiments, the incorporation of a range of scales in the investigation of warming effects (both spatial and temporal), as well as the inclusion of a diversity of tropical forest sites. Finally, we highlight areas of tropical forest research where notably few data are available, including temperature effects on: nutrient cycling

  20. Wildfires, Ecosystem Services, and Biodiversity in Tropical Dry Forest in India.

    PubMed

    Schmerbeck, Joachim; Fiener, Peter

    2015-08-01

    This review is intended to contribute to the understanding of the interlinkage between wildfire in India's tropical dry forest (TDF) and selected ecosystem services (ES), namely forest provisioning and water regulating services, as well as biodiversity. TDF covers approximately 146,000 km(2) (4.4%) of India, whereas according to the MODIS fire product about 2200 km(2) (1.4%) burns per year. As studies on wildfire effects upon ESs and biodiversity in Indian TDFs are rare we partly transferred findings from other (dry) forest areas to the environmental situation in India. In India (intentionally lit) wildfires have a very important connection to local livelihoods and the availability of non-wood forest products. Very important adverse long-term effects are the deterioration of forest ecosystems and soil degradation. The potential for TDF to regulate hydrological cycles is expected to be greater in the absence of fire than with it. A general judgment on the effect of fire on biodiversity is difficult as it depends on the community and species involved but a loss of biodiversity under regular burnings is apparent. Consequently, forest managers need sound knowledge regarding the interplay of wildfires and ecosystem behavior in general and more specific knowledge regarding the effects on taxa being considered for conservation efforts. Generally, much more research is needed to understand the trade-offs between the short-term benefits gained from forest provisioning services and long-term adverse effects. PMID:25900601

  1. Wildfires, Ecosystem Services, and Biodiversity in Tropical Dry Forest in India

    NASA Astrophysics Data System (ADS)

    Schmerbeck, Joachim; Fiener, Peter

    2015-08-01

    This review is intended to contribute to the understanding of the interlinkage between wildfire in India's tropical dry forest (TDF) and selected ecosystem services (ES), namely forest provisioning and water regulating services, as well as biodiversity. TDF covers approximately 146,000 km2 (4.4 %) of India, whereas according to the MODIS fire product about 2200 km2 (1.4 %) burns per year. As studies on wildfire effects upon ESs and biodiversity in Indian TDFs are rare we partly transferred findings from other (dry) forest areas to the environmental situation in India. In India (intentionally lit) wildfires have a very important connection to local livelihoods and the availability of non-wood forest products. Very important adverse long-term effects are the deterioration of forest ecosystems and soil degradation. The potential for TDF to regulate hydrological cycles is expected to be greater in the absence of fire than with it. A general judgment on the effect of fire on biodiversity is difficult as it depends on the community and species involved but a loss of biodiversity under regular burnings is apparent. Consequently, forest managers need sound knowledge regarding the interplay of wildfires and ecosystem behavior in general and more specific knowledge regarding the effects on taxa being considered for conservation efforts. Generally, much more research is needed to understand the trade-offs between the short-term benefits gained from forest provisioning services and long-term adverse effects.

  2. Wildfires, Ecosystem Services, and Biodiversity in Tropical Dry Forest in India.

    PubMed

    Schmerbeck, Joachim; Fiener, Peter

    2015-08-01

    This review is intended to contribute to the understanding of the interlinkage between wildfire in India's tropical dry forest (TDF) and selected ecosystem services (ES), namely forest provisioning and water regulating services, as well as biodiversity. TDF covers approximately 146,000 km(2) (4.4%) of India, whereas according to the MODIS fire product about 2200 km(2) (1.4%) burns per year. As studies on wildfire effects upon ESs and biodiversity in Indian TDFs are rare we partly transferred findings from other (dry) forest areas to the environmental situation in India. In India (intentionally lit) wildfires have a very important connection to local livelihoods and the availability of non-wood forest products. Very important adverse long-term effects are the deterioration of forest ecosystems and soil degradation. The potential for TDF to regulate hydrological cycles is expected to be greater in the absence of fire than with it. A general judgment on the effect of fire on biodiversity is difficult as it depends on the community and species involved but a loss of biodiversity under regular burnings is apparent. Consequently, forest managers need sound knowledge regarding the interplay of wildfires and ecosystem behavior in general and more specific knowledge regarding the effects on taxa being considered for conservation efforts. Generally, much more research is needed to understand the trade-offs between the short-term benefits gained from forest provisioning services and long-term adverse effects.

  3. Integrating remotely sensed land cover observations and a biogeochemical model for estimating forest ecosystem carbon dynamics

    USGS Publications Warehouse

    Liu, J.; Liu, S.; Loveland, T.R.; Tieszen, L.L.

    2008-01-01

    Land cover change is one of the key driving forces for ecosystem carbon (C) dynamics. We present an approach for using sequential remotely sensed land cover observations and a biogeochemical model to estimate contemporary and future ecosystem carbon trends. We applied the General Ensemble Biogeochemical Modelling System (GEMS) for the Laurentian Plains and Hills ecoregion in the northeastern United States for the period of 1975-2025. The land cover changes, especially forest stand-replacing events, were detected on 30 randomly located 10-km by 10-km sample blocks, and were assimilated by GEMS for biogeochemical simulations. In GEMS, each unique combination of major controlling variables (including land cover change history) forms a geo-referenced simulation unit. For a forest simulation unit, a Monte Carlo process is used to determine forest type, forest age, forest biomass, and soil C, based on the Forest Inventory and Analysis (FIA) data and the U.S. General Soil Map (STATSGO) data. Ensemble simulations are performed for each simulation unit to incorporate input data uncertainty. Results show that on average forests of the Laurentian Plains and Hills ecoregion have been sequestrating 4.2 Tg C (1 teragram = 1012 gram) per year, including 1.9 Tg C removed from the ecosystem as the consequences of land cover change. ?? 2008 Elsevier B.V.

  4. Ecosystem Consequences of Tree Monodominance for Nitrogen Cycling in Lowland Tropical Forest

    PubMed Central

    Brookshire, E. N. Jack; Thomas, Steven A.

    2013-01-01

    Understanding how plant functional traits shape nutrient limitation and cycling on land is a major challenge in ecology. This is especially true for lowland forest ecosystems of the tropics which can be taxonomically and functionally diverse and rich in bioavailable nitrogen (N). In many tropical regions, however, diverse forests occur side-by-side with monodominant forest (one species >60% of canopy); the long-term biogeochemical consequences of tree monodominance are unclear. Particularly uncertain is whether the monodominant plant-soil system modifies nutrient balance at the ecosystem level. Here, we use chemical and stable isotope techniques to examine N cycling in old-growth Mora excelsa and diverse watershed rainforests on the island of Trinidad. Across 26 small watershed forests and 4 years, we show that Mora monodominance reduces bioavailable nitrate in the plant-soil system to exceedingly low levels which, in turn, results in small hydrologic and gaseous N losses at the watershed-level relative to adjacent N-rich diverse forests. Bioavailable N in soils and streams remained low and remarkably stable through time in Mora forests; N levels in diverse forests, on the other hand, showed high sensitivity to seasonal and inter-annual rainfall variation. Total mineral N losses from diverse forests exceeded inputs from atmospheric deposition, consistent with N saturation, while losses from Mora forests did not, suggesting N limitation. Our measures suggest that this difference cannot be explained by environmental factors but instead by low internal production and efficient retention of bioavailable N in the Mora plant-soil system. These results demonstrate ecosystem-level consequences of a tree species on the N cycle opposite to cases where trees enhance ecosystem N supply via N2 fixation and suggest that, over time, Mora monodominance may generate progressive N draw-down in the plant-soil system. PMID:23936215

  5. CO2 soil fluxes at bog and forest ecosystems in southern taiga of European Russia

    NASA Astrophysics Data System (ADS)

    Ivanov, Dmitrii; Ivanov, Aleksey; Vasenev, Ivan; Kurbatova, Juliya

    2015-04-01

    Bogs and spruce forests are typical natural ecosystems of the southern taiga of European Russia. They play an important role in carbon balance between soil and atmosphere. In the Central Forest Reserve (33°00' E, 56°30' N) for over 15 years conduct research of these processes. One of the research methods of CO2 emissions is the chamber method, which allows to analyze the local variation of the intensity of fluxes and its depending of the type of vegetation, microrelief and meteorological parameters. Period of measurements was 5 months - from June to November 2013-2014. In the bog were investigated 3 areas - pine boggy forest, as well as hummocks and hollows in the middle of bog. As the forest ecosystem was chosen paludified shallow-peat spruce forest. From the data obtained it can be concluded that in all ecosystems were observed 2 periods with a minimum values of CO2 emission: the first - in early July, associated with a high level of ground water and decrease the intensity of decomposition of organic matter, and the second - in November, associated with natural processes and seasonal cooling. The average intensity of CO2 emissions in summer-autumn season between all ecosystems varied greatly: in the boggy pine forest - 500 mgCO2/m2*h), hummocks - 550 mgCO2/m2*h, hollows - 290 mgCO2/m2*h) and paludified shallow-peat spruce forest - 750 mgCO2/m2*h. Based on these researches, it was found that the intensity of CO2 emissions significantly below in the bog than in paludified shallow-peat spruce forest because it is limited by the level of ground water. In the paludified shallow-peat spruce forest, fluxes are more depend on soil temperature and less on the groundwater level.

  6. Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China, 2004-2010.

    PubMed

    Zhang, Xinyu; Xu, Zhiwei; Sun, Xiaomin; Dong, Wenyi; Ballantine, Deborah

    2013-05-01

    The nitrate-nitrogen (NO3(-)-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations, representing typical agro- and forest ecosystems, were assessed using monitoring data collected between 2004 and 2010. Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater, and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made. Results indicated that most of the NO3(-)-N concentrations in groundwater from the agro- and forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard: Quality Standard for Ground Water (< or = 20 mg/L). Over the study period, the average NO3(-)-N concentrations were significantly higher in agro-ecosystems (4.1 +/- 0.33 mg/L) than in forest ecosystems (0.5 +/- 0.04 mg/L). NO3(-)-N concentrations were relatively higher (> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems. These elevated concentrations occurred mainly in the Ansai, Yucheng, Linze, Fukang, Akesu, and Cele field sites, which were located in arid and semi-arid areas where irrigation rates are high. We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations. PMID:24218832

  7. Nitrate in shallow groundwater in typical agricultural and forest ecosystems in China, 2004-2010.

    PubMed

    Zhang, Xinyu; Xu, Zhiwei; Sun, Xiaomin; Dong, Wenyi; Ballantine, Deborah

    2013-05-01

    The nitrate-nitrogen (NO3(-)-N) concentrations from shallow groundwater wells situated in 29 of the Chinese Ecosystem Research Network field stations, representing typical agro- and forest ecosystems, were assessed using monitoring data collected between 2004 and 2010. Results from this assessment permit a national scale assessment of nitrate concentrations in shallow groundwater, and allow linkages between nitrate concentrations in groundwater and broad land use categories to be made. Results indicated that most of the NO3(-)-N concentrations in groundwater from the agro- and forest ecosystems were below the Class 3 drinking water standard stated in the Chinese National Standard: Quality Standard for Ground Water (< or = 20 mg/L). Over the study period, the average NO3(-)-N concentrations were significantly higher in agro-ecosystems (4.1 +/- 0.33 mg/L) than in forest ecosystems (0.5 +/- 0.04 mg/L). NO3(-)-N concentrations were relatively higher (> 10 mg N /L) in 10 of the 43 wells sampled in the agricultural ecosystems. These elevated concentrations occurred mainly in the Ansai, Yucheng, Linze, Fukang, Akesu, and Cele field sites, which were located in arid and semi-arid areas where irrigation rates are high. We suggest that improvements in N fertilizer application and irrigation management practices in the arid and semi-arid agricultural ecosystems of China are the key to managing groundwater nitrate concentrations.

  8. Biomass is the main driver of changes in ecosystem process rates during tropical forest succession.

    PubMed

    Lohbeck, Madelon; Poorter, Lourens; Martínez-Ramos, Miguel; Bongers, Frans

    2015-05-01

    Over half of the world's forests are disturbed, and the rate at which ecosystem processes recover after disturbance is important for the services these forests can provide. We analyze the drivers' underlying changes in rates of key ecosystem processes (biomass productivity, litter productivity, actual litter decomposition, and potential litter decomposition) during secondary succession after shifting cultivation in wet tropical forest of Mexico. We test the importance of three alternative drivers of ecosystem processes: vegetation biomass (vegetation quantity hypothesis), community-weighted trait mean (mass ratio hypothesis), and functional diversity (niche complementarity hypothesis) using structural equation modeling. This allows us to infer the relative importance of different mechanisms underlying ecosystem process recovery. Ecosystem process rates changed during succession, and the strongest driver was aboveground biomass for each of the processes. Productivity of aboveground stem biomass and leaf litter as well as actual litter decomposition increased with initial standing vegetation biomass, whereas potential litter decomposition decreased with standing biomass. Additionally, biomass productivity was positively affected by community-weighted mean of specific leaf area, and potential decomposition was positively affected by functional divergence, and negatively by community-weighted mean of leaf dry matter content. Our empirical results show that functional diversity and community-weighted means are of secondary importance for explaining changes in ecosystem process rates during tropical forest succession. Instead, simply, the amount of vegetation in a site is the major driver of changes, perhaps because there is a steep biomass buildup during succession that overrides more subtle effects of community functional properties on ecosystem processes. We recommend future studies in the field of biodiversity and ecosystem functioning to separate the effects of

  9. Monitoring gradual ecosystem change using Landsat time series analyses: case studies in selected forest and rangeland ecosystems

    USGS Publications Warehouse

    Vogelmann, James E.; Xian, George; Homer, Collin G.; Tolk, Brian

    2012-01-01

    The focus of the study was to assess gradual changes occurring throughout a range of natural ecosystems using decadal Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM +) time series data. Time series data stacks were generated for four study areas: (1) a four scene area dominated by forest and rangeland ecosystems in the southwestern United States, (2) a sagebrush-dominated rangeland in Wyoming, (3) woodland adjacent to prairie in northwestern Nebraska, and (4) a forested area in the White Mountains of New Hampshire. Through analyses of time series data, we found evidence of gradual systematic change in many of the natural vegetation communities in all four areas. Many of the conifer forests in the southwestern US are showing declines related to insects and drought, but very few are showing evidence of improving conditions or increased greenness. Sagebrush communities are showing decreases in greenness related to fire, mining, and probably drought, but very few of these communities are showing evidence of increased greenness or improving conditions. In Nebraska, forest communities are showing local expansion and increased canopy densification in the prairie–woodland interface, and in the White Mountains high elevation understory conifers are showing range increases towards lower elevations. The trends detected are not obvious through casual inspection of the Landsat images. Analyses of time series data using many scenes and covering multiple years are required in order to develop better impressions and representations of the changing ecosystem patterns and trends that are occurring. The approach described in this paper demonstrates that Landsat time series data can be used operationally for assessing gradual ecosystem change across large areas. Local knowledge and available ancillary data are required in order to fully understand the nature of these trends.

  10. The new flora of northeastern USA: quantifying introduced plant species occupancy in forest ecosystems.

    PubMed

    Schulz, Bethany K; Gray, Andrew N

    2013-05-01

    Introduced plant species have significant negative impacts in many ecosystems and are found in many forests around the world. Some factors linked to the distribution of introduced species include fragmentation and disturbance, native species richness, and climatic and physical conditions of the landscape. However, there are few data sources that enable the assessment of introduced species occupancy in native plant communities over broad regions. Vegetation data from 1,302 forest inventory plots across 24 states in northeastern and mid-western USA were used to examine and compare the distribution of introduced species in relation to forest fragmentation across ecological provinces and forest types, and to examine correlations between native and introduced species richness. There were 305 introduced species recorded, and 66 % of all forested plots had at least one introduced species. Forest edge plots had higher constancy and occupancy of introduced species than intact forest plots, but the differences varied significantly among ecological provinces and, to a lesser degree, forest types. Weak but significant positive correlations between native and introduced species richness were observed most often in intact forests. Rosa multiflora was the most common introduced species recorded across the region, but Hieracium aurantiacum and Epipactus helleborine were dominant in some ecological provinces. Identifying regions and forest types with high and low constancies and occupation by introduced species can help target forest stands where management actions will be the most effective. Identifying seemingly benign introduced species that are more prevalent than realized will help focus attention on newly emerging invasives.

  11. Management impacts on water quality of forests and rangelands. Forest Service general technical report (Final)

    SciTech Connect

    Binkley, D.; Brown, T.C.

    1993-11-01

    The report compiles information about the effects of management practices on water quality in forests and rangelands. Chapter 1 summarizes water quality concerns on all types of lands. Chapters 2 through 9 focus on physical, chemical, and biological aspects of the forest and rangeland water quality. Chapter 10 describes the federal laws and state programs that are intended to control or monitor forest and rangeland management practices affecting water quality. The final chapter reviews available information about the economic efficiency of nonpoint source pollution programs on forestlands.

  12. Recent Forest Disturbance History in the Greater Yellowstone Ecosystem Reconstructed using Remote Sensing and Management Record

    NASA Astrophysics Data System (ADS)

    Zhao, F.; Huang, C.; Zhu, Z.

    2014-12-01

    The Greater Yellowstone Ecosystem (GYE), located in Central Rocky Mountains of United States, is of complex ecological and land management histories along with different land ownerships. What are effects of the different land management practices (such as those by national parks vs. national forests) on ecosystem disturbances and carbon balance? We present here the methods and results of a study on forest disturbance history over the GYE from 1984 to 2010 reconstructed from Landsat time series stacks and local management records. Annual forest fire, harvest and other disturbances were tracked and separated by integrating a model called Vegetation Change Tracker and the Support Vector Machine algorithm. Local management records were separated into training and validation data for the disturbance maps. Area statistics and rates of disturbances were quantified and compared across GYE land ownership over the multi-decade period and interpreted for implications of these changes for forest management and carbon analysis. Our results indicate that during the study interval (1984 - 2010), GYE National Parks (NPs) and Wilderness Area (WA) had higher percentages of area of forests disturbed compared to GYE National Forests (NF). Within the GYE NPs, over 45% of the forest lands were disturbed at least once during the study period, the majority (37%) was by wildfire. For GYE wilderness area, the total disturbance was 30% of forest with 19.4% by wildfire and 10.6% by other disturbances. In Bridger-Teton NF, 14.7% of forest was disturbed and 3.6%, 0.5% and 10.6% of forest were disturbed by fire, harvest and other disturbances, respectively. For Caribou-Targhee NF, 25% of total forest was disturbed during this time interval and 1.5%, 6.4% and 17.1% of forest were disturbed by fire, harvest and other disturbances, respectively.

  13. Improving SWAT for simulating water and carbon fluxes of forest ecosystems.

    PubMed

    Yang, Qichun; Zhang, Xuesong

    2016-11-01

    As a widely used watershed model for assessing impacts of anthropogenic and natural disturbances on water quantity and quality, the Soil and Water Assessment Tool (SWAT) has not been extensively tested in simulating water and carbon fluxes of forest ecosystems. Here, we examine SWAT simulations of evapotranspiration (ET), net primary productivity (NPP), net ecosystem exchange (NEE), and plant biomass at ten AmeriFlux forest sites across the U.S. We identify unrealistic radiation use efficiency (Bio_E), large leaf to biomass fraction (Bio_LEAF), and missing phosphorus supply from parent material weathering as the primary causes for the inadequate performance of the default SWAT model in simulating forest dynamics. By further revising the relevant parameters and processes, SWAT's performance is substantially improved. Based on the comparison between the improved SWAT simulations and flux tower observations, we discuss future research directions for further enhancing model parameterization and representation of water and carbon cycling for forests. PMID:27401278

  14. Calcium depletion in a Southeastern United States forest ecosystem

    USGS Publications Warehouse

    Huntington, T.G.; Hooper, R.P.; Johnson, C.E.; Aulenbach, Brent T.; Cappellato, R.; Blum, A.E.

    2000-01-01

    Forest soil Ca depletion through leaching and vegetation uptake may threaten long-term sustainability of forest productivity in the southeastern USA. This study was conducted to assess Ca pools and fluxes in a representative southern Piedmont forest to determine the soil Ca depletion rate. Soil Ca storage, Ca inputs in atmospheric deposition, and outputs in soil leaching and vegetation uptake were investigated at the Panola Mountain Research Watershed (PMRW) near Atlanta, GA. Average annual outputs of 12.3 kg ha-1 yr-1 in uptake into merchantable wood and 2.71 kg ha-1 yr-1 soil leaching exceeded inputs in atmospheric deposition of 2.24 kg ha-1 yr-1. The annual rate of Ca uptake into merchantable wood exceeds soil leaching losses by a factor of more than five. The potential for primary mineral weathering to provide a substantial amount of Ca inputs is low. Estimates of Ca replenishment through mineral weathering in the surface 1 m of soil and saprolite was estimated to be 0.12 kg ha-1 yr-1. The weathering rate in saprolite and partially weathered bedrock below the surface 1 m is similarly quite low because mineral Ca is largely depleted. The soil Ca depletion rate at PMRW is estimated to be 12.7 kg ha-1 yr-1. At PMRW and similar hardwood-dominated forests in the Piedmont physiographic province, Ca depletion will probably reduce soil reserves to less than the requirement for a merchantable forest stand in ???80 yr. This assessment and comparable analyses at other southeastern USA forest sites suggests that there is a strong potential for a regional problem in forest nutrition in the long term.Forest soil Ca depletion through leaching and vegetation uptake may threaten long-term sustainability of forest productivity in the southeastern USA. This study was conducted to assess Ca pools and fluxes in a representative southern Piedmont forest to determine the soil Ca depletion rate. Soil Ca storage, Ca inputs in atmospheric deposition, and outputs in soil leaching and

  15. Increased forest ecosystem carbon and nitrogen storage from nitrogen rich bedrock.

    PubMed

    Morford, Scott L; Houlton, Benjamin Z; Dahlgren, Randy A

    2011-09-01

    Nitrogen (N) limits the productivity of many ecosystems worldwide, thereby restricting the ability of terrestrial ecosystems to offset the effects of rising atmospheric CO(2) emissions naturally. Understanding input pathways of bioavailable N is therefore paramount for predicting carbon (C) storage on land, particularly in temperate and boreal forests. Paradigms of nutrient cycling and limitation posit that new N enters terrestrial ecosystems solely from the atmosphere. Here we show that bedrock comprises a hitherto overlooked source of ecologically available N to forests. We report that the N content of soils and forest foliage on N-rich metasedimentary rocks (350-950 mg N kg(-1)) is elevated by more than 50% compared with similar temperate forest sites underlain by N-poor igneous parent material (30-70 mg N kg(-1)). Natural abundance N isotopes attribute this difference to rock-derived N: (15)N/(14)N values for rock, soils and plants are indistinguishable in sites underlain by N-rich lithology, in marked contrast to sites on N-poor substrates. Furthermore, forests associated with N-rich parent material contain on average 42% more carbon in above-ground tree biomass and 60% more carbon in the upper 30 cm of the soil than similar sites underlain by N-poor rocks. Our results raise the possibility that bedrock N input may represent an important and overlooked component of ecosystem N and C cycling elsewhere. PMID:21886160

  16. Increased forest ecosystem carbon and nitrogen storage from nitrogen rich bedrock.

    PubMed

    Morford, Scott L; Houlton, Benjamin Z; Dahlgren, Randy A

    2011-08-31

    Nitrogen (N) limits the productivity of many ecosystems worldwide, thereby restricting the ability of terrestrial ecosystems to offset the effects of rising atmospheric CO(2) emissions naturally. Understanding input pathways of bioavailable N is therefore paramount for predicting carbon (C) storage on land, particularly in temperate and boreal forests. Paradigms of nutrient cycling and limitation posit that new N enters terrestrial ecosystems solely from the atmosphere. Here we show that bedrock comprises a hitherto overlooked source of ecologically available N to forests. We report that the N content of soils and forest foliage on N-rich metasedimentary rocks (350-950 mg N kg(-1)) is elevated by more than 50% compared with similar temperate forest sites underlain by N-poor igneous parent material (30-70 mg N kg(-1)). Natural abundance N isotopes attribute this difference to rock-derived N: (15)N/(14)N values for rock, soils and plants are indistinguishable in sites underlain by N-rich lithology, in marked contrast to sites on N-poor substrates. Furthermore, forests associated with N-rich parent material contain on average 42% more carbon in above-ground tree biomass and 60% more carbon in the upper 30 cm of the soil than similar sites underlain by N-poor rocks. Our results raise the possibility that bedrock N input may represent an important and overlooked component of ecosystem N and C cycling elsewhere.

  17. Effects of disturbance and climate change on ecosystem performance in the Yukon River Basin boreal forest

    USGS Publications Warehouse

    Wylie, Bruce K.; Rigge, Matthew B.; Brisco, Brian; Mrnaghan, Kevin; Rover, Jennifer R.; Long, Jordan

    2014-01-01

    A warming climate influences boreal forest productivity, dynamics, and disturbance regimes. We used ecosystem models and 250 m satellite Normalized Difference Vegetation Index (NDVI) data averaged over the growing season (GSN) to model current, and estimate future, ecosystem performance. We modeled Expected Ecosystem Performance (EEP), or anticipated productivity, in undisturbed stands over the 2000–2008 period from a variety of abiotic data sources, using a rule-based piecewise regression tree. The EEP model was applied to a future climate ensemble A1B projection to quantify expected changes to mature boreal forest performance. Ecosystem Performance Anomalies (EPA), were identified as the residuals of the EEP and GSN relationship and represent performance departures from expected performance conditions. These performance data were used to monitor successional events following fire. Results suggested that maximum EPA occurs 30–40 years following fire, and deciduous stands generally have higher EPA than coniferous stands. Mean undisturbed EEP is projected to increase 5.6% by 2040 and 8.7% by 2070, suggesting an increased deciduous component in boreal forests. Our results contribute to the understanding of boreal forest successional dynamics and its response to climate change. This information enables informed decisions to prepare for, and adapt to, climate change in the Yukon River Basin forest.

  18. New Projections of Global Forest Carbon and Ecosystems at Risk for Increased Greenhouse Gas Emissions From Disturbance and Forest Degradation

    NASA Astrophysics Data System (ADS)

    Klooster, S.; Potter, C. S.; Genovese, V. B.; Gross, P. M.; Kumar, V.; Boriah, S.; Mithal, V.; Castilla-Rubio, J.

    2009-12-01

    Widely cited forest carbon values from look-up tables and statistical correlations with aboveground biomass have proven to be inadequate to discern details of national carbon stocks in forest pools. Similarly, global estimates based on biome-average (tropical, temperate, boreal, etc.) carbon measurements are generally insufficient to support REDD incentives (Reductions in Emission from Deforestation in Developing countries). The NASA-CASA (Carnegie-Ames-Stanford Approach) ecosystem model published by Potter et al. (1999 and 2003) offers several unique advantages for carbon accounting that cannot be provided by conventional inventory techniques. First, CASA uses continuous satellite observations to map land cover status and changes in vegetation on a monthly time interval over the past 25 years. NASA satellites observe areas that are too remote or rugged for conventional inventory-based techniques to measure. Second, CASA estimates both aboveground and belowground pools of carbon in all ecosystems (forests, shrublands, croplands, and rangelands). Carbon storage estimates for forests globally are currently being estimated for the Cisco Planetary Skin open collaborative platform (www.planetaryskin.org ) in a new series of CASA model runs using the latest input data from the NASA MODIS satellites, from 2000 to the present. We have also developed an approach for detection of large-scale ecosystem disturbance (LSED) events based on sustained declines in the same satellite greenness data used for CASA modeling. This approach is global in scope, covers more than a decade of observations, and encompasses all potential categories of major ecosystem disturbance - physical, biogenic, and anthropogenic, using advanced methods of data mining and analysis. In addition to quantifying forest areas at various levels of risk for loss of carbon storage capacity, our data mining approaches for LSED events can be adapted to detect and map biophysically unsuitable areas for deforestation

  19. Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Quideau, S. A.; Swallow, M. J. B.; Prescott, C. E.; Grayston, S. J.; Oh, S.-W.

    2013-04-01

    Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability, and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.

  20. Comparing soil biogeochemical processes in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Quideau, S. A.; Swallow, M. J. B.; Prescott, C. E.; Grayston, S. J.; Oh, S.-W.

    2013-08-01

    Emulating the variability that exists in the natural landscape prior to disturbance should be a goal of soil reconstruction and land reclamation efforts following resource extraction. Long-term ecosystem sustainability within reclaimed landscapes can only be achieved with the re-establishment of biogeochemical processes between reconstructed soils and plants. In this study, we assessed key soil biogeochemical attributes (nutrient availability, organic matter composition, and microbial communities) in reconstructed, novel, anthropogenic ecosystems, covering different reclamation treatments following open-cast mining for oil extraction. We compared the attributes to those present in a range of natural soils representative of mature boreal forest ecosystems in the same area of Northern Alberta. Soil nutrient availability was determined in situ with resin probes, organic matter composition was described with 13C nuclear magnetic resonance spectroscopy and soil microbial community structure was characterized using phospholipid fatty acid analysis. Significant differences among natural ecosystems were apparent in nutrient availability and seemed more related to the dominant tree cover than to soil type. When analyzed together, all natural forests differed significantly from the novel ecosystems, in particular with respect to soil organic matter composition. However, there was some overlap between the reconstructed soils and some of the natural ecosystems in nutrient availability and microbial communities, but not in organic matter characteristics. Hence, our results illustrate the importance of considering the range of natural landscape variability and including several soil biogeochemical attributes when comparing novel, anthropogenic ecosystems to the mature ecosystems that constitute ecological targets.

  1. Late Holocene history of the forest ecosystems from Gabon

    NASA Astrophysics Data System (ADS)

    Ngomanda, A.; Maley, J.

    2003-04-01

    In Gabon sediment cores were collected in three sites close to the equator (PALEOFORGA Program). First in the lake Maridor inside the coastal forest/savanna mosaic, second in the lake Nguène at the foot of the Monts de Cristal which is characterized by very rich and diverse rain forests, and third in the lake Kamalété inside of the forest/savanna mosaic of the Lopé Réserve, located in the central part of Gabon. Until now two cores were pollen analyzed : 38 samples in the core KAM-1 from Kamalété and 42 samples in NGUE-1 from Nguène. The base of core KAM-1 is dated at ca. 1400 C/14 years BP and ca. 5000 C/14 years BP for base of the core NGUE-1. For the time span between the present day and ca.1400 C/14 years BP the main results are similar in these two cores, showing a phase of forest extension. In Kamalété, between ca. 1400 and 500 C/14 years BP one observes a strong increase of the pionnier forest taxa, then until the present day time an increase of more mature forest taxa. In the lowest part of the Nguène core, between ca. 5000 and 4000 C/14 years BP one observes the end of an important phase of mature forest, characterized by large percentages of Caesalpiniaceae tree taxa and other primary taxa, and between ca. 4000 and 1400 C/14 years BP, two sucessive phase characterized by important extensions of pionnier tree taxa. During the 20 th century in south Cameroon, CentreAfrique, Gabon and Congo, the main result of the ECOFIT Program has shown a widespread phenomenon of forest transgression upon the savannas. Such result are apparently the continuation of the forest extension evidenced above in Kamalété and Nguène. (Presentation and attendance to the Congress by only Alfred NGOMANDA, student/ thésard)

  2. Mycorrhizal weathering of apatite as an important calcium source in base-poor forest ecosystems.

    PubMed

    Blum, Joel D; Klaue, Andrea; Nezat, Carmen A; Driscoll, Charles T; Johnson, Chris E; Siccama, Thomas G; Eagar, Christopher; Fahey, Timothy J; Likens, Gene E

    2002-06-13

    The depletion of calcium in forest ecosystems of the northeastern USA is thought to be a consequence of acidic deposition and to be at present restricting the recovery of forest and aquatic systems now that acidic deposition itself is declining. This depletion of calcium has been inferred from studies showing that sources of calcium in forest ecosystems namely, atmospheric deposition and mineral weathering of silicate rocks such as plagioclase, a calcium-sodium silicate do not match calcium outputs observed in forest streams. It is therefore thought that calcium is being lost from exchangeable and organically bound calcium in forest soils. Here we investigate the sources of calcium in the Hubbard Brook experimental forest, through analysis of calcium and strontium abundances and strontium isotope ratios within various soil, vegetation and hydrological pools. We show that the dissolution of apatite (calcium phosphate) represents a source of calcium that is comparable in size to known inputs from atmospheric sources and silicate weathering. Moreover, apatite-derived calcium was utilized largely by ectomycorrhizal tree species, suggesting that mycorrhizae may weather apatite and absorb the released ions directly, without the ions entering the exchangeable soil pool. Therefore, it seems that apatite weathering can compensate for some of the calcium lost from base-poor ecosystems, and should be considered when estimating soil acidification impacts and calcium cycling.

  3. Development of the BIOME-BGC model for the simulation of managed Moso bamboo forest ecosystems.

    PubMed

    Mao, Fangjie; Li, Pingheng; Zhou, Guomo; Du, Huaqiang; Xu, Xiaojun; Shi, Yongjun; Mo, Lufeng; Zhou, Yufeng; Tu, Guoqing

    2016-05-01

    Numerical models are the most appropriate instrument for the analysis of the carbon balance of terrestrial ecosystems and their interactions with changing environmental conditions. The process-based model BIOME-BGC is widely used in simulation of carbon balance within vegetation, litter and soil of unmanaged ecosystems. For Moso bamboo forests, however, simulations with BIOME-BGC are inaccurate in terms of the growing season and the carbon allocation, due to the oversimplified representation of phenology. Our aim was to improve the applicability of BIOME-BGC for managed Moso bamboo forest ecosystem by implementing several new modules, including phenology, carbon allocation, and management. Instead of the simple phenology and carbon allocation representations in the original version, a periodic Moso bamboo phenology and carbon allocation module was implemented, which can handle the processes of Moso bamboo shooting and high growth during "on-year" and "off-year". Four management modules (digging bamboo shoots, selective cutting, obtruncation, fertilization) were integrated in order to quantify the functioning of managed ecosystems. The improved model was calibrated and validated using eddy covariance measurement data collected at a managed Moso bamboo forest site (Anji) during 2011-2013 years. As a result of these developments and calibrations, the performance of the model was substantially improved. Regarding the measured and modeled fluxes (gross primary production, total ecosystem respiration, net ecosystem exchange), relative errors were decreased by 42.23%, 103.02% and 18.67%, respectively. PMID:26921563

  4. Hubbard Brook Ecosystem Study: biogeochemistry of lead in the northern hardwood forest

    SciTech Connect

    Smith, W.; Siccama, T.G.

    1981-09-01

    The average annual Pb input to the northern hardwood forest at the Hubbard Brook Experimental Forest in central New Hampshire was 266 g ha/sup -1/ year /sup -1/ based on 4 years of records. Lead output via streamwater and eroded particulate matter was 5.0 and 1.1 g ha/sup -1/ year/sup -1/, respectively. Lead concentration in precipitation averaged 22 ..mu..g liter/sup -1/ and showed a significant decline over the 4 sample years (1975 to 1978). Lead input to the ecosystem via meteorological vectors is accumulated in the forest floor. Total current Pb content of the forest floor was 8.6 kg ha/sup -1/ and showed no significant differences along the elevation gradient of the watershed (400 to 800 m). Lead concentration in the forest floor was maximum on the ridge due to a minimum forest floor mass relative to the rest of the watershed. Within the forest floor, maximum Pb concentration is in the fermented (F) layer. Total Pb content of the forest biomass (stems greater than or equal to 10 cm dbh) was 1248 g ha/sup -1/. Lead concentration in the biota was in the following order: lichens (213 ..mu..g g/sup -1/) > mosses (190 ..mu..g g/sup -1/) tree twigs (26 ..mu..g g/sup -1/) > roots (20 ..mu..g g/sup -1/) > bark (19 ..mu..g g/sup -1/) > leaves (7 ..mu..g g/sup -1/) = bracket fungi (7 ..mu..g g/sup -1/) > wood (0.7 ..mu..g g/sup -1/). Disturbance of the forest ecosystem through harvest cutting, other than through increased runoff, increased erosion, and transport of particulate matter, does not alter the biogeochemistry of Pb and does not result in increased mobility and export of Pb due to gross or subtle alterations of the behavior of Pb in the ecosystem.

  5. Biogeochemical response of a northeastern forest ecosystem to biosolids amendments.

    PubMed

    Banaitis, Michael R; Fernandez, Ivan J; Wilson, Cullen; Norton, Stephen A; Dail, D Bryan

    2009-01-01

    In the northeastern United States interest in the use of biosolids on forest lands is growing due to the prevalence of extensive forests and market incentives for waste disposal, yet much of the regulatory framework for biosolids land application is based on agronomic practice. This study evaluated the response of soils in a young ( approximately 20 yr old) deciduous forest to lime-stabilized biosolids amendments focusing on (i) the temporal and spatial evolution of the pH response, (ii) soil exchangeable cation response, (iii) the risk of trace metal accumulations, and (iv) a bioindicator of treatments (i.e., foliar chemistry). Eighteen plots were established in two study phases with lime-stabilized biosolids loading targets of 0 (control), 4.5, 6.7, 13.4, 20.2, 26.9, and 33.6 Mg (megagram) calcium carbonate equivalents (CCE) ha(-1), with the lowest target rate of addition representing the current regulated loading limit for forest biosolids applications in Maine. The pH of the O horizon increased immediately >2 pH units, and then declined with time, while B horizon pH increased gradually, taking over 1 yr to achieve approximately 1.0 pH unit increase at the highest loading target. O-horizon exchangeable Ca concentration increases dominated soil chemical change and resulted in decreases in exchangeable H and Al. Few significant increases in soil trace metal concentrations had occurred at any soil depth after 1 yr of treatment. Foliar response generally reflected changes in soil chemistry, with Ca concentration increases most significant. This research provides critical insights on forest soil response to application of lime-stabilized biosolids and suggests opportunities for higher loading targets in forests should be examined.

  6. Final Report to DOE’s Office of Science (BER) submitted by Ram Oren (PI) of DE-FG02-00ER63015 (ended on 09/14/2009) entitled “Controls of Net Ecosystem Exchange at an Old Field, a Pine Plantation, & a Hardwood Forest under Identical Climatic & Edaphic Conditions”

    SciTech Connect

    Oren, Ram; Oishi, AC; Palmroth, Sari; Butnor, JR; Johnsen, KH

    2014-03-17

    The project yielded papers on fluxes (energy, water and carbon dioxide)between each ecosystem and the atmosphere, and explained the temporal dynamics of fluxes based on intrinsic (physiology, canopy leaf area and structure) and extrinsic (atmospheric and edaphic conditions). Comparisons between any two of the ecosystems, and among all three followed, attributing differences in behavior to different patterns of phenology and differential sensitivities to soil and atmospheric humidity. Finally, data from one-to-three of the ecosystems (incorporated into FluxNet data archive) were used in syntheses across AmeriFlux sites and even more broadly across FluxNet sites.

  7. Effects of repeated fires on ecosystem C and N stocks along a fire induced forest/grassland gradient

    NASA Astrophysics Data System (ADS)

    Cheng, Chih-Hsin; Chen, Yung-Sheng; Huang, Yu-Hsuan; Chiou, Chyi-Rong; Lin, Chau-Chih; Menyailo, Oleg V.

    2013-03-01

    Repeated fires might have different effect on ecosystem carbon storage than a single fire event, but information on repeated fires and their effects on forest ecosystems and carbon storage is scarce. However, changes in climate, vegetation composition, and human activities are expected to make forests more susceptible to fires that recur with relatively high frequency. In this study, the effects of repeated fires on ecosystem carbon and nitrogen stocks were examined along a fire-induced forest/grassland gradient wherein the fire events varied from an unburned forest to repeatedly burned grassland. Results from the study show repeated fires drastically decreased ecosystem carbon and nitrogen stocks along the forest/grassland gradient. The reduction began with the disappearance of living tree biomass, and followed by the loss of soil carbon and nitrogen. Within 4 years of the onset of repeated fires on the unburned forest, the original ecosystem carbon and nitrogen stocks were reduced by 42% and 21%, respectively. Subsequent fires caused cumulative reductions in ecosystem carbon and nitrogen stocks by 68% and 44% from the original ecosystem carbon and nitrogen stocks, respectively. The analyses of carbon budgets calculated by vegetation composition and stable isotopic δ13C values indicate that 84% of forest-derived carbon is lost at grassland, whereas the gain of grass-derived carbon only compensates 18% for this loss. Such significant losses in ecosystem carbon and nitrogen stocks suggest that the effects of repeated fires have substantial impacts on ecosystem and soil carbon and nitrogen cycling.

  8. Remote sensing of canopy chemistry and nitrogen cycling in temperate forest ecosystems

    NASA Technical Reports Server (NTRS)

    Wessman, Carol A.; Aber, John D.; Peterson, David L.; Melillo, Jerry M.

    1988-01-01

    The use of images acquired by the Airborne Imaging Spectrometer, an experimental high-spectral resolution imaging sensor developed by NASA, to estimate the lignin concentration of whole forest canopies in Wisconsin is reported. The observed strong relationship between canopy lignin concentration and nitrogen availability in seven undisturbed forest ecosystems on Blackhawk Island, Wisconsin, suggests that canopy lignin may serve as an index for site nitrogen status. This predictive relationship presents the opportunity to estimate nitrogen-cycling rates across forested landscapes through remote sensing.

  9. Global topics and novel approaches in the study of air pollution, climate change and forest ecosystems.

    PubMed

    Sicard, Pierre; Augustaitis, Algirdas; Belyazid, Salim; Calfapietra, Carlo; de Marco, Alessandra; Fenn, Mark; Bytnerowicz, Andrzej; Grulke, Nancy; He, Shang; Matyssek, Rainer; Serengil, Yusuf; Wieser, Gerhard; Paoletti, Elena

    2016-06-01

    Research directions from the 27th conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems (2015) reflect knowledge advancements about (i) Mechanistic bases of tree responses to multiple climate and pollution stressors, in particular the interaction of ozone (O3) with nitrogen (N) deposition and drought; (ii) Linking genetic control with physiological whole-tree activity; (iii) Epigenetic responses to climate change and air pollution; (iv) Embedding individual tree performance into the multi-factorial stand-level interaction network; (v) Interactions of biogenic and anthropogenic volatile compounds (molecular, functional and ecological bases); (vi) Estimating the potential for carbon/pollution mitigation and cost effectiveness of urban and peri-urban forests; (vii) Selection of trees adapted to the urban environment; (viii) Trophic, competitive and host/parasite relationships under changing pollution and climate; (ix) Atmosphere-biosphere-pedosphere interactions as affected by anthropospheric changes; (x) Statistical analyses for epidemiological investigations; (xi) Use of monitoring for the validation of models; (xii) Holistic view for linking the climate, carbon, N and O3 modelling; (xiii) Inclusion of multiple environmental stresses (biotic and abiotic) in critical load determinations; (xiv) Ecological impacts of N deposition in the under-investigated areas; (xv) Empirical models for mechanistic effects at the local scale; (xvi) Broad-scale N and sulphur deposition input and their effects on forest ecosystem services; (xvii) Measurements of dry deposition of N; (xviii) Assessment of evapotranspiration; (xix) Remote sensing assessment of hydrological parameters; and (xx) Forest management for maximizing water provision and overall forest ecosystem services. Ground-level O3 is still the phytotoxic air pollutant of major concern to forest health. Specific issues about O3 are: (xxi) Developing dose-response relationships and

  10. Consolidating new paradigms in large-scale monitoring and assessment of forest ecosystems.

    PubMed

    Corona, Piermaria

    2016-01-01

    Forests provide a wide range of ecosystem services from which people benefit, and upon which all life depends. However, any rational decision related to the maintenance and enhancement of the multiple functions provided by the forests needs to be based on objective, reliable information. As such, forest monitoring and assessment are rapidly evolving as new information needs arise or new techniques and tools become available. Global change issues and utilities from ecosystem management are distinctively to be considered, so that forest inventory and mapping are broadening their scope towards multipurpose resources surveys. Recent changes in forest management perspective have promoted the consideration of forests as complex adaptive systems, thereby highlighting the need to account that such approaches actually work: forest monitoring and assessment are then expected to address and fully incorporate this perspective at global scale, seeking to support planning and management decisions that are evidence-based. This contribution provides selected considerations on the above mentioned issues, in the form of a commented discussion with examples from the literature produced in the last decade. PMID:26514075

  11. Consolidating new paradigms in large-scale monitoring and assessment of forest ecosystems.

    PubMed

    Corona, Piermaria

    2016-01-01

    Forests provide a wide range of ecosystem services from which people benefit, and upon which all life depends. However, any rational decision related to the maintenance and enhancement of the multiple functions provided by the forests needs to be based on objective, reliable information. As such, forest monitoring and assessment are rapidly evolving as new information needs arise or new techniques and tools become available. Global change issues and utilities from ecosystem management are distinctively to be considered, so that forest inventory and mapping are broadening their scope towards multipurpose resources surveys. Recent changes in forest management perspective have promoted the consideration of forests as complex adaptive systems, thereby highlighting the need to account that such approaches actually work: forest monitoring and assessment are then expected to address and fully incorporate this perspective at global scale, seeking to support planning and management decisions that are evidence-based. This contribution provides selected considerations on the above mentioned issues, in the form of a commented discussion with examples from the literature produced in the last decade.

  12. n-Alkane distributions as indicators of novel ecosystem development in western boreal forest soils

    NASA Astrophysics Data System (ADS)

    Norris, Charlotte; Dungait, Jennifer; Quideau, Sylvie

    2013-04-01

    Novel ecosystem development is occurring within the western boreal forest of Canada due to land reclamation following surface mining in the Athabasca Oil Sands Region. Sphagnum peat is the primary organic matter amendment used to reconstruct soils in the novel ecosystems. We hypothesised that ecosystem recovery would be indicated by an increasing similarity in the biomolecular characteristics of novel reconstructed soil organic matter (SOM) derived from peat to those of natural boreal ecosystems. In this study, we evaluated the use of the homologous series of very long chain (>C20) n-alkanes with odd-over-even predominance as biomarker signatures to monitor the re-establishment of boreal forests on reconstructed soils. The lipids were extracted from dominant vegetation inputs and SOM from a series of natural and novel ecosystem reference plots. We observed unique very long n-alkane signatures of the source vegetation, e.g. Sphagnum sp. was dominated by C31 and aspen (Populus tremuloides Michx.) leaves by C25. Greater concentrations of very long chain n-alkanes were extracted from natural than novel ecosystem SOM (p<0.01), and their distribution differed between the two systems (p<0.001) and reflected the dominant vegetation input. Our results indicate that further research is required to clarify the influence of vegetation or disturbance on the signature of very long chain n-alkanes in SOM; however, the use of n-alkanes as biomarkers of ecosystem development is a promising method.

  13. Assessment of environmental impact zones in the Kola Peninsula forest ecosystems.

    PubMed

    Lukina, N; Nikonov, V

    2001-01-01

    This paper describes the condition of forest ecosystems subjected to smelter pollution in the Kola peninsula. This assessment is based on the parameters of the biogeochemical cycle. The defoliation index was used to delimit three basic forest states: background, defoliating, sparse. Close to the smelter, due to expansion of the area not covered by vegetation, a fourth type of state, so-called "industrial deserts", has been observed. The concentrations of sulphur, copper and nickel in the precipitation in the forests generally declined with distance from the smelter. The defoliating forests are noted for the highest Ca, Mg, K concentrations in the summer precipitation. In sparse forests and industrial deserts a decrease in the Ca, Mg, K concentrations in the summer precipitation in comparison with the defoliating forests, despite the particle emissions, could be attributed to the reduction in forest biomass. The higher levels of soil and soil leachate carbon and acidity in the defoliating forests was due to higher litterfall and to the higher dissolution of fulvic acids by the acidic precipitation. This increase in organic matter levels affects soil cation exchange capacity and cation saturation. The pine trees demonstrated significant changes in the uptake of elements in all types of forests under pollution. Elevated levels of S, Ni, Cu and K and reduced levels of Mg, Mn and Zn were found in the needles of different age classes.

  14. Structural equation modelling reveals plant-community drivers of carbon storage in boreal forest ecosystems.

    PubMed

    Jonsson, Micael; Wardle, David A

    2010-02-23

    Boreal forest ecosystems are important drivers of the global carbon (C) cycle by acting as both sinks and sources of atmospheric CO(2). While several factors have been proposed as determining the ability of boreal forest to function as C sinks, little is known about their relative importance. In this study, we applied structural equation modelling to a previously published dataset involving 30 boreal-forested islands that vary greatly in their historic fire regime, in order to explore the simultaneous influence of several factors believed to be important in influencing above-ground, below-ground and total ecosystem C accumulation. We found that wildfire was a major driver of ecosystem C sequestration, and exerted direct effects on below-ground C storage (presumably through humus combustion) and indirect effects on both above-ground and below-ground C storage through altering plant-community composition. By contrast, plant diversity influenced only below-ground C storage (and even then only weakly), while net primary productivity and decomposition had no detectable effect. Our results suggest that while boreal forests have great potential for storing significant amounts of C, traits of dominant plant species that promote below-ground C accumulation and the absence of wildfire are the most important drivers of C sequestration in these ecosystems. PMID:19755530

  15. [Design of dynamic simulation system for carbon cycle in forest ecosystem].

    PubMed

    Zhu, Jian-Gang; Yu, Xin-Xiao; Zhang, Zhen-Ming; Wang, Chen; Gan, Jing; Wang, Xiao-Ping; Li, Jin-Hai

    2009-11-01

    Modeling techniques are indispensable for the researches on the carbon cycle of forest ecosystem. In this paper, a new general simulation system FORCASS (FORest CArbon Simulation System) was designed and developed under Simulink environment, with the objectives of modeling the carbon cycle dynamics of forest ecosystems. A comprehensive analysis on the framework, design solution, and development process showed that the FORCASS was feasible. This simulation system had the characteristics of 1) it divided the carbon storage in forest ecosystem into four compartments, i.e., vegetation, litter, soil, and animal, and took into account the carbon flows between the compartments, possessing high mechanism and easily to be comprehended, 2) it was a process-based system, taking the Richards growth function of vegetation component biomass carbon storage as the input to solve difference equations, and was easily to export the outputs such as net primary productivity (NPP) and net ecosystem productivity (NEP) at different stand ages, and 3) it had the explicit expansibility because it was developed based on a general framework for carbon cycle patterns.

  16. Effect of environmental variables and stand structure on ecosystem respiration components in a Mediterranean beech forest.

    PubMed

    Guidolotti, Gabriele; Rey, Ana; D'Andrea, Ettore; Matteucci, Giorgio; De Angelis, Paolo

    2013-09-01

    The temporal variability of ecosystem respiration (RECO) has been reported to have important effects on the temporal variability of net ecosystem exchange, the net amount of carbon exchanged between an ecosystem and the atmosphere. However, our understanding of ecosystem respiration is rather limited compared with photosynthesis or gross primary productivity, particularly in Mediterranean montane ecosystems. In order to investigate how environmental variables and forest structure (tree classes) affect different respiration components and RECO in a Mediterranean beech forest, we measured soil, stem and leaf CO2 efflux rates with dynamic chambers and RECO by the eddy-covariance technique over 1 year (2007-2008). Ecosystem respiration showed marked seasonal variation, with the highest rates in spring and autumn and the lowest in summer. We found that the soil respiration (SR) was mainly controlled by soil water content below a threshold value of 0.2 m(3) m(-3), above which the soil temperature explained temporal variation in SR. Stem CO2 effluxes were influenced by air temperature and difference between tree classes with higher rates measured in dominant trees than in co-dominant ones. Leaf respiration (LR) varied significantly between the two canopy layers considered. Non-structural carbohydrates were a very good predictor of LR variability. We used these measurements to scale up respiration components to ecosystem respiration for the whole canopy and obtained cumulative amounts of carbon losses over the year. Based on the up-scaled chamber measurements, the relative contributions of soil, stem and leaves to the total annual CO2 efflux were: 56, 8 and 36%, respectively. These results confirm that SR is the main contributor of ecosystem respiration and provided an insight on the driving factors of respiration in Mediterranean montane beech forests. PMID:24044943

  17. Seasonal Variation in the Carbon Isotope Ratio of Ecosystem Respiration in Two Coniferous Forests

    NASA Astrophysics Data System (ADS)

    McDowell, N. G.; Bowling, D.; Schauer, A.; Irvine, J.; Bond, B. J.; Law, B.; Ehleringer, J. R.

    2003-12-01

    We examined weekly variation in the stable carbon isotope signature of ecosystem respiration (δ 13CR) using the Keeling plot approach at two forests in Oregon USA: a wet (>2300 mm annual precipitation) 20-year-old Pseudotsuga menziesii plantation located in the Coast Range near the Pacific Ocean, and a dry ( ˜520 mm annual precipitation) 250-year-old Pinus ponderosa forest located on the eastern slope of the Cascade Mountains. The two forests experience similar regional weather patterns with wet winters and dry summers, but the coastal site has milder temperatures and greater soil and atmospheric water content. Air was sampled on 51 and 42 separate nights at the Pinus and Pseudotsuga forests, respectively, between 2001 and 2002. Both forests exhibited greater intra-annual variation in δ 13CR than has been previously observed in C3 ecosystems (>8.0 ‰ over the year). Mean annual δ 13CR matched that expected based on annual precipitation, averaging -25.4 ‰ at the Pinus forest and -26.2 ‰ at the Pseudotsuga forest. Variability in δ 13CR at both sites was highest during seasons when rainfall was abundant (autumn, winter and spring) and lowest during summer drought. During the period of drought, soil temperature was positively correlated with δ 13CR at both forests. When all seasons were analyzed, δ 13CR was negatively correlated with soil water content at both forests. The Pseudotsuga forest was more strongly coupled to soil and atmospheric water content than the Pinus forest. This difference could be related to availability of a deep water source at the Pinus forest that buffers it from drought effects. δ 13CR at the Pinus forest was significantly but weakly related to canopy conductance suggesting that δ 13CR is coupled to canopy gas exchange. δ 13CR was significantly correlated between the two forests after removal of outliers associated with extreme, site-specific meteorological events (i.e. local freezes), demonstrating that δ 13CR is coupled

  18. Phosphorus status of soils from contrasting forested ecosystems in southwestern Siberia

    NASA Astrophysics Data System (ADS)

    Achat, D. L.; Bakker, M. R.; Zeller, B.; Derrien, D.; Barsukov, P.; Nikitich, P.

    2011-12-01

    Phosphorus is one of the most limiting nutrients in many ecosystems and mineral reserves available for fertilizer production are forecasted to last for no more than 100 yrs. Crop requirements for P are often lower in forests than in agriculture and P fertilization to forest ecosystems is not very common on a global scale. In southern Siberia, expected climate change would lead to higher overall precipitation, higher temperatures and subsequently to changes in land use (i.e. agricultural land could increase on detriment of forests). In the present work we evaluated P status in four forested ecosystems in southwestern Siberia including 1 site with lowland Populus tremula, and 3 upland sites in the Salair mountains with Populus tremula, Abies siberica or with small forest openings. The upland sites feature twice higher productivity than the lowland sites and it was suggested that thick snow cover on those sites would enable winter activity of microbial communities leading to faster soil degradation processes and higher nutrient availability. We thus wanted to test whether biological processes in the upland sites were of larger impact on P status than in the lowland sites. We combined 32P isotopic dilution techniques (for diffusive P), chemical extractions (for total P, organic P) and fumigation/incubation/respiration methods (for microbial P) to test this hypothesis. Additional soil analyses (C, N and othes) were performed. Results will be interpreted in the light of the exising knowledge on botany, climate, pedology and expected implications for future land use, would this occur to change.

  19. Disturbance legacies increase the resilience of forest ecosystem structure, composition, and functioning

    PubMed Central

    Seidl, Rupert; Rammer, Werner; Spies, Thomas A.

    2015-01-01

    Disturbances are key drivers of forest ecosystem dynamics, and forests are well adapted to their natural disturbance regimes. However, as a result of climate change, disturbance frequency is expected to increase in the future in many regions. It is not yet clear how such changes might affect forest ecosystems, and which mechanisms contribute to (current and future) disturbance resilience. We studied a 6364-ha landscape in the western Cascades of Oregon, USA, to investigate how patches of remnant old-growth trees (as one important class of biological legacies) affect the resilience of forest ecosystems to disturbance. Using the spatially explicit, individual-based, forest landscape model iLand, we analyzed the effect of three different levels of remnant patches (0%, 12%, and 24% of the landscape) on 500-year recovery trajectories after a large, high-severity wildfire. In addition, we evaluated how three different levels of fire frequency modulate the effects of initial legacies. We found that remnant live trees enhanced the recovery of total ecosystem carbon (TEC) stocks after disturbance, increased structural complexity of forest canopies, and facilitated the recolonization of late-seral species (LSS). Legacy effects were most persistent for indicators of species composition (still significant 500 years after disturbance), while TEC (i.e., a measure of ecosystem functioning) was least affected, with no significant differences among legacy scenarios after 236 years. Compounding disturbances were found to dampen legacy effects on all indicators, and higher initial legacy levels resulted in elevated fire severity in the second half of the study period. Overall, disturbance frequency had a stronger effect on ecosystem properties than the initial level of remnant old-growth trees. A doubling of the historically observed fire frequency to a mean fire return interval of 131 years reduced TEC by 10.5% and lowered the presence of LSS on the landscape by 18.1% on average

  20. Estimating daytime ecosystem respiration to improve estimates of gross primary production of a temperate forest.

    PubMed

    Sun, Jinwei; Wu, Jiabing; Guan, Dexin; Yao, Fuqi; Yuan, Fenghui; Wang, Anzhi; Jin, Changjie

    2014-01-01

    Leaf respiration is an important component of carbon exchange in terrestrial ecosystems, and estimates of leaf respiration directly affect the accuracy of ecosystem carbon budgets. Leaf respiration is inhibited by light; therefore, gross primary production (GPP) will be overestimated if the reduction in leaf respiration by light is ignored. However, few studies have quantified GPP overestimation with respect to the degree of light inhibition in forest ecosystems. To determine the effect of light inhibition of leaf respiration on GPP estimation, we assessed the variation in leaf respiration of seedlings of the dominant tree species in an old mixed temperate forest with different photosynthetically active radiation levels using the Laisk method. Canopy respiration was estimated by combining the effect of light inhibition on leaf respiration of these species with within-canopy radiation. Leaf respiration decreased exponentially with an increase in light intensity. Canopy respiration and GPP were overestimated by approximately 20.4% and 4.6%, respectively, when leaf respiration reduction in light was ignored compared with the values obtained when light inhibition of leaf respiration was considered. This study indicates that accurate estimates of daytime ecosystem respiration are needed for the accurate evaluation of carbon budgets in temperate forests. In addition, this study provides a valuable approach to accurately estimate GPP by considering leaf respiration reduction in light in other ecosystems.

  1. Agricultural capacity and conservation in high biodiversity forest ecosystems.

    PubMed

    Gorenflo, L J; Brandon, Katrina

    2005-05-01

    Agricultural development is a leading cause of habitat destruction that increasingly threatens global biodiversity. To help understand the likelihood and implications of agricultural expansion in areas of high conservation importance, this article examines agricultural suitability in forested portions of biodiversity hotspots and tropical wilderness areas, regions with especially rich concentrations of species found nowhere else. The study employs geographic information system technology to examine suitability for six crop categories in selected conservation localities worldwide: those portions of regions containing high biodiversity, protected areas (e.g. national parks) within these regions, and 10-km bands around the protected areas that are dominated by forest. Analyses reveal low suitability for most crop categories under both commercial and subsistence scenarios, with a few exceptions. In most cases, adequate planning can enable the coexistence of agriculture and biodiversity without compromising either.

  2. Preliminary analysis of ERS-1 SAR for forest ecosystem studies

    NASA Technical Reports Server (NTRS)

    Dobson, M. G.; Pierce, Leland; Sarabandi, Kamal; Ulaby, Fawwaz T.; Sharik, Terry

    1992-01-01

    An image obtained by the C-band VV-polarized ERS-1 SAR is examined with respect to potential land applications. A scene obtained near noon on August 15, 1991, along the U.S.-Canadian border near Sault Ste. Marie is calibrated relative to an array of trihedral corner reflectors and active radar calibrators distributed across the swath. Extensive contemporaneous ground observations of forest stands are used to predict the radar backscattering coefficient sigma at the time of the SAR overpass using a first-order vector radiative transfer model. These predictions generally agree with the calibrated ERS-1 data to within 1 dB. It is demonstrated that the dynamic range of sigma is sufficient to perform limited discrimination of various forest and grassland communities even for a single-date observation. Furthermore, retrieval of near-surface soil moisture is feasible for grass-covered soils when plant biomass is less than 1 tonne/ha.

  3. Modelling forest ecosystem dynamics using multitemporal multispectral scanner (MSS) data

    NASA Astrophysics Data System (ADS)

    Jarvis, C.

    1994-03-01

    An empirical model of forest succession was developed using MSS data. Images from 1976 and 1987 were classified and registered to assess vegetation change. Data were analyzed to determine the proportion of each landscape class that changed, and these proportions were used to develop a Markov Model. The simulation model was run to produce forest cover for 99 years. MSS data were classified into six classes with an overall accuracy of 93%. The landscape composition remained relatively constant, but over half the individual units changed, indicating a dynamic equilibrium. Results of the Markov model show a theoretical climax community that stabilizes rapidly. Over 60% of the area was composed of conifer, supporting the concept of a conifer dominated climax. However, continuous levels of other classes were maintained, indicating an inherently heterogeneous landscape.

  4. Modelling forest ecosystem dynamics using Multitemporal Multispectral Scanner (MSS) data

    SciTech Connect

    Jarvis, C. )

    1994-03-01

    An empirical model of forest succession was developed using Multitemporal Multispectral Scanner (MSS) data. Images from 1976 and 1987 were classified and registered to assess vegetation change. Data were analyzed to determine the proportion of each landscape class that changed, and these proportions were used to develop a Markov Model. The simulation model was run to produce forest cover for 99 years. MSS data were classified into six classes with an overall accuracy of 93 STET. The landscape composition remained relatively constant, but over half the individual units changed, indicating a dynamic equilibrium. Results of the Markov model show a theoretical climax community that stabilized rapidly. Over 60 STET of the area was composed of conifer, supporting the concept of a conifer dominated climax. However, continuous levels of other classes were maintained, indicating an inherently heterogeneous landscape.

  5. Tipping point of a conifer forest ecosystem under severe drought

    NASA Astrophysics Data System (ADS)

    Huang, Kaicheng; Yi, Chuixiang; Wu, Donghai; Zhou, Tao; Zhao, Xiang; Blanford, William J.; Wei, Suhua; Wu, Hao; Ling, Du; Li, Zheng

    2015-02-01

    Drought-induced tree mortality has recently received considerable attention. Questions have arisen over the necessary intensity and duration thresholds of droughts that are sufficient to trigger rapid forest declines. The values of such tipping points leading to forest declines due to drought are presently unknown. In this study, we have evaluated the potential relationship between the level of tree growth and concurrent drought conditions with data of the tree growth-related ring width index (RWI) of the two dominant conifer species (Pinus edulis and Pinus ponderosa) in the Southwestern United States (SWUS) and the meteorological drought-related standardized precipitation evapotranspiration index (SPEI). In this effort, we determined the binned averages of RWI and the 11 month SPEI within the month of July within each bin of 30 of RWI in the range of 0-3000. We found a significant correlation between the binned averages of RWI and SPEI at the regional-scale under dryer conditions. The tipping point of forest declines to drought is predicted by the regression model as SPEItp = -1.64 and RWItp = 0, that is, persistence of the water deficit (11 month) with intensity of -1.64 leading to negligible growth for the conifer species. When climate conditions are wetter, the correlation between the binned averages of RWI and SPEI is weaker which we believe is most likely due to soil water and atmospheric moisture levels no longer being the dominant factor limiting tree growth. We also illustrate a potential application of the derived tipping point (SPEItp = -1.64) through an examination of the 2002 extreme drought event in the SWUS conifer forest regions. Distinguished differences in remote-sensing based NDVI anomalies were found between the two regions partitioned by the derived tipping point.

  6. Identifying the location of fire refuges in wet forest ecosystems.

    PubMed

    Berry, Laurence E; Driscoll, Don A; Stein, John A; Blanchard, Wade; Banks, Sam C; Bradstock, Ross A; Lindenmayer, David B

    2015-12-01

    The increasing frequency of large, high-severity fires threatens the survival of old-growth specialist fauna in fire-prone forests. Within topographically diverse montane forests, areas that experience less severe or fewer fires compared with those prevailing in the landscape may present unique resource opportunities enabling old-growth specialist fauna to survive. Statistical landscape models that identify the extent and distribution of potential fire refuges may assist land managers to incorporate these areas into relevant biodiversity conservation strategies. We used a case study in an Australian wet montane forest to establish how predictive fire simulation models can be interpreted as management tools to identify potential fire refuges. We examined the relationship between the probability of fire refuge occurrence as predicted by an existing fire refuge model and fire severity experienced during a large wildfire. We also examined the extent to which local fire severity was influenced by fire severity in the surrounding landscape. We used a combination of statistical approaches, including generalized linear modeling, variogram analysis, and receiver operating characteristics and area under the curve analysis (ROC AUC). We found that the amount of unburned habitat and the factors influencing the retention and location of fire refuges varied with fire conditions. Under extreme fire conditions, the distribution of fire refuges was limited to only extremely sheltered, fire-resistant regions of the landscape. During extreme fire conditions, fire severity patterns were largely determined by stochastic factors that could not be predicted by the model. When fire conditions were moderate, physical landscape properties appeared to mediate fire severity distribution. Our study demonstrates that land managers can employ predictive landscape fire models to identify the broader climatic and spatial domain within which fire refuges are likely to be present. It is essential

  7. Acidic deposition, plant pests, and the fate of forest ecosystems.

    PubMed

    Gragnani, A; Gatto, M; Rinaldi, S

    1998-12-01

    We present and analyze a nonlinear dynamical system modelling forest-pests interactions and the way they are affected by acidic deposition. The model includes mechanisms of carbon and nitrogen exchange between soil and vegetation, biomass decomposition and microbial mineralization, and defoliation by pest grazers, which are partially controlled by avian or mammalian predators. Acidic deposition is assumed to directly damage vegetation, to decrease soil pH, which in turn damages roots and inhibits microbial activity, and to predispose trees to increased pest attack. All the model parameters are set to realistic values except the inflow of protons to soil and the predation mortality inflicted to the pest which are allowed to vary inside reasonable ranges. A numerical bifurcation analysis with respect to these two parameters is carried out. Five functioning modes are uncovered: (i) pest-free equilibrium; (ii) pest persisting at endemic equilibrium; (iii) forest-pest permanent oscillations; (iv) bistable behavior with the system converging either to pest-free equilibrium or endemic pest presence in accordance with initial conditions; (v) bistable behavior with convergence to endemic pest presence or permanent oscillations depending on initial conditions. Catastrophic bifurcations between the different behavior modes are possible, provided the abundance of predators is not too small. Numerical simulation shows that increasing acidic load can lead the forest to collapse in a short time period without important warning signals.

  8. Modelling Net Ecosystem Exchange and LUE in Mediterranean Oak Forest by Satellite Remote Sensing

    NASA Astrophysics Data System (ADS)

    Tramontana, Gianluca; Papale, Dario

    2011-01-01

    Net Ecosystem Exchange (NEE) is a key factor defining CO2 fluxes between atmosphere and ecosystems and CO2 flux measurements at individual eddy covariance flux sites provide valuable information on the seasonal dynamics of NEE. In this work, we developed and validated a satellite-based Light Use Efficiency (LUE) model to estimate NEE for a typical oak forest located in Central Italy. Satellite data were acquired by Moderate resolution spectroradiometer (MODIS) sensor installed on board Terra satellite. Oak forest studied is coppice managed; 2 eddy-covariance towers are located inside two forests parcels having different ages. We proposed to estimate LUE like function of mean brightness temperature, Normalized Difference Water Index (NDWI) and Photochemical Reflectance Index (PRI). Empirical multiple regressions models (MR) and Artificial Neural Network (ANN) were parameterized and validated using subset of data acquired by both the stations. Daily, 8-day and monthly temporal resolutions were investigated and accuracy estimation in space and time was performed.

  9. A general ecophysiological framework for modelling the impact of pests and pathogens on forest ecosystems.

    PubMed Central

    Dietze, Michael C; Matthes, Jaclyn Hatala

    2014-01-01

    Forest insects and pathogens (FIPs) have enormous impacts on community dynamics, carbon storage and ecosystem services, however, ecosystem modelling of FIPs is limited due to their variability in severity and extent. We present a general framework for modelling FIP disturbances through their impacts on tree ecophysiology. Five pathways are identified as the basis for functional groupings: increases in leaf, stem and root turnover, and reductions in phloem and xylem transport. A simple ecophysiological model was used to explore the sensitivity of forest growth, mortality and ecosystem fluxes to varying outbreak severity. Across all pathways, low infection was associated with growth reduction but limited mortality. Moderate infection led to individual tree mortality, whereas high levels led to stand-level die-offs delayed over multiple years. Delayed mortality is consistent with observations and critical for capturing biophysical, biogeochemical and successional responses. This framework enables novel predictions under present and future global change scenarios. PMID:25168168

  10. The effect of increased air humidity on northern deciduous forest ecosystem - a FAHM study.

    NASA Astrophysics Data System (ADS)

    Ostonen, Ivika; Rosenvald, Katrin; Tullus, Arvo; Parts, Kaarin; Sellin, Arne; Kupper, Priit; Sõber, Jaak; Sõber, Anu; Uri, Veiko; Aosaar, Jürgen; Varik, Mats; Lõhmus, Krista

    2013-04-01

    At northern latitudes a rise in atmospheric humidity and precipitation is predicted as a consequence of global climate change. In 2006 an unique experimental facility for free air humidity manipulation (FAHM) was established in Estonia to study the functioning of deciduous forest ecosystem under altered humidity conditions. The experimental site contains humidified and control plots, each includes four types of forest ecosystem: two overstorey species (planted hybrid aspen (Populus tremula L. × P. tremuloides Michx. and silver birch (Betula pendula Roth.)) both split into two types according to understorey vegetation (diverse "forest" understory and early successional grasses). We investigated the productivity, biomass allocation and functioning of silver birch forest ecosystem in response to elevated atmospheric humidity (on average 7% over the ambient level) during four growing seasons (2008-2011). We hypothesized that elevated air humidity facilitates both above- and below-ground growth and accumulation of plant biomass. During the first three experimental seasons height, stem diameter, and stem volume (D2H) increments of trees, biomass of understory in aboveground and fine root biomass in belowground were similar or significantly reduced in humidified plots. Only the fine root and rhizome biomass of the understory was twice higher in humidified plots. However, fine root turnover speeded up for both tree and understory roots. The trends in above-ground growth changed in 2011, when current annual increments of trees height, diameter, stem volume and fine root biomass were higher in humidified plots. Functionally, trees hydraulic conductance was significantly higher and stem sap flux lower for humidified trees coinciding with significantly higher biomass of primary (in majority ectomycorrhizal) roots, morphologically thinner and longer root tips and higher specific root length. Humidification caused a shift in the root tips colonizing fungal community towards the

  11. Multi-trophic resilience of boreal lake ecosystems to forest fires

    USGS Publications Warehouse

    Lewis, Tyler L.; Lindberg, Mark S.; Schmutz, Joel A.; Bertram, M.R.

    2014-01-01

    Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

  12. Multi-trophic resilience of boreal lake ecosystems to forest fires.

    PubMed

    Lewis, Tyler L; Lindberg, Mark S; Schmutz, Joel A; Bertram, Mark R

    2014-05-01

    Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll a levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change.

  13. Multi-trophic resilience of boreal lake ecosystems to forest fires.

    PubMed

    Lewis, Tyler L; Lindberg, Mark S; Schmutz, Joel A; Bertram, Mark R

    2014-05-01

    Fires are the major natural disturbance in the boreal forest, and their frequency and intensity will likely increase as the climate warms. Terrestrial nutrients released by fires may be transported to boreal lakes, stimulating increased primary productivity, which may radiate through multiple trophic levels. Using a before-after-control-impact (BACI) design, with pre- and postfire data from burned and unburned areas, we examined effects of a natural fire across several trophic levels of boreal lakes, from nutrient and chlorophyll levels, to macroinvertebrates, to waterbirds. Concentrations of total nitrogen and phosphorus were not affected by the fire. Chlorophyll a levels were also unaffected, likely reflecting the stable nutrient concentrations. For aquatic invertebrates, we found that densities of three functional feeding groups did not respond to the fire (filterers, gatherers, scrapers), while two groups increased (shredders, predators). Amphipods accounted for 98% of shredder numbers, and we hypothesize that fire-mediated habitat changes may have favored their generalist feeding and habitat ecology. This increase in amphipods may, in turn, have driven increased predator densities, as amphipods were the most numerous invertebrate in our lakes and are commonly taken as prey. Finally, abundance of waterbird young, which feed primarily on aquatic invertebrates, was not affected by the fire. Overall, ecosystems of our study lakes were largely resilient to forest fires, likely due to their high initial nutrient concentrations and small catchment sizes. Moreover, this resilience spanned multiple trophic levels, a significant result for ecologically similar boreal regions, especially given the high potential for increased fires with future climate change. PMID:25000757

  14. Spatial and Temporal Analysis of Drought Effects in a Heterogeneous Semi-Arid Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Assal, T.; Anderson, P. J.; Sibold, J.

    2015-12-01

    Drought-induced forest mortality has been documented across genera in recent years in western North America. Understanding patterns of mortality and plant response to severe drought is important to resource managers, given the frequency of these events are expected to increase in the future. Remote sensing studies have documented changes in forest properties due to direct and indirect effects of drought; however, few have addressed this at local scales needed to characterize highly heterogeneous ecosystems in the forest-shrubland ecotone. We analyzed a 22-year Landsat time series (1985-2012) to determine changes in forest that experienced a relatively dry decade punctuated by two years of extreme drought. We assessed the relationship between vegetation indices and field measures, applied the index to trend analysis to uncover the location, direction and timing of change, and assessed the interaction of climate on topography. The Normalized Difference Moisture Index (NDMI) had the strongest correlation with plant area index (R2 = 0.64) and canopy gap fraction (R2 = 0.65). During the study period, 25% of the forested area experienced a significant (p < 0.05) negative trend in NDMI, compared to less than 10% in a positive trend. Trends were not consistent across forest type as a larger amount of coniferous forest was impacted by negative trends than deciduous forest. Southern aspects were least likely to exhibit a negative trend and north aspects were most prevalent. Field plots with a negative trend had a lower live density, and higher amounts of standing dead and down trees compared to plots with no trend. Our analysis identifies spatially explicit patterns of long-term trends anchored with ground based evidence to highlight areas of forest that are resistant, persistent and vulnerable to severe drought. The results provide a long-term perspective for the resource management of this area and can be applied to similar ecosystems throughout western North America.

  15. Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective.

    PubMed

    Smale, Dan A; Burrows, Michael T; Moore, Pippa; O'Connor, Nessa; Hawkins, Stephen J

    2013-10-01

    Kelp forests along temperate and polar coastlines represent some of most diverse and productive habitats on the Earth. Here, we synthesize information from >60 years of research on the structure and functioning of kelp forest habitats in European waters, with particular emphasis on the coasts of UK and Ireland, which represents an important biogeographic transition zone that is subjected to multiple threats and stressors. We collated existing data on kelp distribution and abundance and reanalyzed these data to describe the structure of kelp forests along a spatial gradient spanning more than 10° of latitude. We then examined ecological goods and services provided by kelp forests, including elevated secondary production, nutrient cycling, energy capture and flow, coastal defense, direct applications, and biodiversity repositories, before discussing current and future threats posed to kelp forests and identifying key knowledge gaps. Recent evidence unequivocally demonstrates that the structure of kelp forests in the NE Atlantic is changing in response to climate- and non-climate-related stressors, which will have major implications for the structure and functioning of coastal ecosystems. However, kelp-dominated habitats along much of the NE Atlantic coastline have been chronically understudied over recent decades in comparison with other regions such as Australasia and North America. The paucity of field-based research currently impedes our ability to conserve and manage these important ecosystems. Targeted observational and experimental research conducted over large spatial and temporal scales is urgently needed to address these knowledge gaps.

  16. Application of sewage sludge to non-agricultural ecosystems: Impacts of nitrogen on forests

    SciTech Connect

    Efroymson, R.A.; Tharp, M.L.; Luxmoore, R.J.; Sample, B.E.; Barnthouse, L.W.; Daniel, F.B.

    1995-12-31

    The Clean Water Act (CWA) of 1977 directed EPA to establish standards for use and disposal of sewage sludge (biosolids). This report is part of a larger study evaluating nutrient and contaminant impacts associated with the land application of biosolids in non-agricultural ecosystems. Ecological risk assessments rarely focus on nutrients as stressors. The nutrient components of municipal sewage sludge may impact tree community composition, growth and production, habitat and forage quality for wildlife, and nutrient cycling. The focus here is on three forest ecosystems: northwestern Douglas-fir forest (Pack Forest, WA), southeastern loblolly pine plantation (Athens, GA), and eastern deciduous forest (Hubbard Brook, NH). A model called LINKAGES has been developed at ORNL to examine the relationships between nitrogen cycling and long-term forest stand dynamics, limited by climate and soil water status. Plant-available nitrogen from biosolids is added in several application scenarios and compared to the no-amendment case. All changes are noted, even if they may be viewed as benefits rather than risks. Model outputs include: above-ground biomass, individual species biomass, net above-ground production, leaf litter, evapotranspiration, available nitrogen, and dead trunks. The changes in plant community composition and production are dependent on the rate, frequency, and duration of sludge application and on the age of the stand at the time of application. Model outputs are compared to empirical studies of forests where biosolids have been applied.

  17. Threats and knowledge gaps for ecosystem services provided by kelp forests: a northeast Atlantic perspective

    PubMed Central

    Smale, Dan A; Burrows, Michael T; Moore, Pippa; O'Connor, Nessa; Hawkins, Stephen J

    2013-01-01

    Kelp forests along temperate and polar coastlines represent some of most diverse and productive habitats on the Earth. Here, we synthesize information from >60 years of research on the structure and functioning of kelp forest habitats in European waters, with particular emphasis on the coasts of UK and Ireland, which represents an important biogeographic transition zone that is subjected to multiple threats and stressors. We collated existing data on kelp distribution and abundance and reanalyzed these data to describe the structure of kelp forests along a spatial gradient spanning more than 10° of latitude. We then examined ecological goods and services provided by kelp forests, including elevated secondary production, nutrient cycling, energy capture and flow, coastal defense, direct applications, and biodiversity repositories, before discussing current and future threats posed to kelp forests and identifying key knowledge gaps. Recent evidence unequivocally demonstrates that the structure of kelp forests in the NE Atlantic is changing in response to climate- and non-climate-related stressors, which will have major implications for the structure and functioning of coastal ecosystems. However, kelp-dominated habitats along much of the NE Atlantic coastline have been chronically understudied over recent decades in comparison with other regions such as Australasia and North America. The paucity of field-based research currently impedes our ability to conserve and manage these important ecosystems. Targeted observational and experimental research conducted over large spatial and temporal scales is urgently needed to address these knowledge gaps. PMID:24198956

  18. [Variation characteristics of CO2 flux in Phyllostachys edulis forest ecosystem in subtropical region of China].

    PubMed

    Sun, Cheng; Jiang, Hong; Zhou, Guo-Mo; Yang, Shuang; Chen, Yun-Fei

    2013-10-01

    By using eddy covariance technique, this paper studied the CO2 flux in a Phyllostachys edulis forest ecosystem with high-efficiency management in Zhejiang Province of China from December, 2010 to November, 2011, and analyzed the variations of net ecosystem exchange (NEE), ecosystem respiration (RE), and gross ecosystem exchange (GEE). During the study period, the monthly NEE was always negative, with the maximum (-99.33 g C x m(-2)) in July and the minimum (-23.49 g C x m(-2)) in November, and the seasonal change showed a bimodal shape. The average diurnal change of the monthly CO2 flux varied greatly from -0.30 g CO2 x m(-2) x s(-1) (January) to -0.60 g CO2 x m(-2) x s(-1) (September). The NEE at the time point of positive and negative conversion had obvious seasonal characteristics. The yearly RE changed in unimodal shape, with the maximum in summer and the minimum in winter. The RE at nighttime had significant negative correlation with soil temperature. The yearly NEE, RE, and GEE were -668.40, 932.55, and -1600.95 g C x m(-2) x a(-1), respectively, among which, the NEE occupied 41.8% of the GEE. As compared with other ecosystems, P. edulis forest ecosystem had a strong capability in carbon sequestration. PMID:24483062

  19. Managing for Climate Change in Western Forest Ecosystems; The Role of Refugia in Adaptation Strategies (Invited)

    NASA Astrophysics Data System (ADS)

    Millar, C. I.; Morelli, T.

    2009-12-01

    Managing forested ecosystems in western North America for adaptation to climate change involves options that depend on resource objectives, landscape conditions, sensitivity to change, and social desires. Strategies range from preserving species and ecosystems in the face of change (resisting change); managing for resilience to change; realigning ecosystems that have been severely altered so that they can adapt successfully; and enabling species to respond to climate changes. We are exploring one extreme in this range of strategies, that is, to manage locations, species, communities, or ecosystems as refugia. This concept is familiar from the Quaternary literature as isolated locations where climates remained warm during cold glacial intervals and wherein species contracted and persisted in small populations. References to refugia have been made in the climate-adaptation literature but little elaborated, and applications have not been described. We are addressing this gap conceptually and in case-studies from national forest and national park environments in California. Using a classification of refugium categories, we extend the concept beyond the original use to include diverse locations and conditions where plant or animal species, or ecosystems of concern, would persist during future changing climatic backgrounds. These locations may be determined as refugial for reasons of local microclimate, substrate, elevation, topographic context, paleohistory, species ecology, or management capacity. Recognizing that species and ecosystems respond to climate change differently, refugium strategies are appropriate in some situations and not others. We describe favorable conditions for using refugium strategies and elaborate specific approaches in Sierra Nevada case studies.

  20. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate

    NASA Astrophysics Data System (ADS)

    Sun, Ge; Duan, Kai; Sun, Shanlei; Caldwell, Peter; Cohen, Erika; McNulty, Steven; Zhang, Yang

    2016-04-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This modeling study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in forest productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m-2 yr-1 (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr-1 (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 ℃) and precipitation (+17 ~ +51 mm yr-1). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services.

  1. Nitrogen leaching from N limited forest ecosystems: the MERLIN model applied to Gårdsjön, Sweden

    NASA Astrophysics Data System (ADS)

    Kjønaas, O. J.; Wright, R. F.

    Chronic deposition of inorganic nitrogen (N) compounds from the atmosphere to forested ecosystems can alter the status of a forest ecosystem from N-limited towards N-rich, which may cause, among other things, increased leaching of inorganic N below the rooting zone. To assess the time aspects of excess N leaching, a process-oriented dynamic model, MERLIN (Model of Ecosystem Retention and Loss of Inorganic Nitrogen), was tested on an N-manipulated catchment at Gårdsjön, Sweden (NITREX project). Naturally generated mature Norway spruce dominates the catchment with Scots pine in drier areas. Since 1991, ammonium nitrate (NH4NO3) solution at a rate of about 35 kg N ha-1 yr-1 (250 mmol m-2 yr-1) has been sprinkled weekly, to simulate increased atmospheric N deposition. MERLIN describes C and N cycles, where rates of uptake and cycling between pools are governed by the C/N ratios of plant and soil pools. The model is calibrated through a hindcast period and then used to predict future trends. A major source of uncertainty in model calibration and prediction is the paucity of good historical information on the specific site and stand history over the hindcast period 1930 to 1990. The model is constrained poorly in an N-limited system. The final calibration, therefore, made use of the results from the 6-year N addition experiment. No independent data set was available to provide a test for the model calibration. The model suggests that most N deposition goes to the labile (LOM) and refractory (ROM) organic matter pools. Significant leaching is predicted to start as the C/N ratio in LOM is reduced from the 1990 value of 35 to <28. At ambient deposition levels, the system is capable of retaining virtually all incoming N over the next 50 years. Increased decomposition rates, however, could simulate nitrate leaching losses. The rate and capacity of N assimilation as well as the change in carbon dynamics are keys to ecosystem changes. Because the knowledge of these parameters

  2. Experimental warming studies on tree species and forest ecosystems: a literature review.

    PubMed

    Chung, Haegeun; Muraoka, Hiroyuki; Nakamura, Masahiro; Han, Saerom; Muller, Onno; Son, Yowhan

    2013-07-01

    Temperature affects a cascade of ecological processes and functions of forests. With future higher global temperatures being inevitable it is critical to understand and predict how forest ecosystems and tree species will respond. This paper reviews experimental warming studies in boreal and temperate forests or tree species beyond the direct effects of higher temperature on plant ecophysiology by scaling up to forest level responses and considering the indirect effects of higher temperature. In direct response to higher temperature (1) leaves emerged earlier and senesced later, resulting in a longer growing season (2) the abundance of herbivorous insects increased and their performance was enhanced and (3) soil nitrogen mineralization and leaf litter decomposition were accelerated. Besides these generalizations across species, plant ecophysiological traits were highly species-specific. Moreover, we showed that the effect of temperature on photosynthesis is strongly dependent on the position of the leaf or plant within the forest (canopy or understory) and the time of the year. Indirect effects of higher temperature included among others higher carbon storage in trees due to increased soil nitrogen availability and changes in insect performance due to alterations in plant ecophysiological traits. Unfortunately only a few studies extrapolated results to forest ecosystem level and considered the indirect effects of higher temperature. Thus more intensive, long-term studies are needed to further confirm the emerging trends shown in this review. Experimental warming studies provide us with a useful tool to examine the cascade of ecological processes in forest ecosystems that will change with future higher temperature. PMID:23689840

  3. Effects of Past Climate Changes on Ecosystem Biogeochemical Cycles in Rocky Mountain Forests and Lakes

    NASA Astrophysics Data System (ADS)

    Shuman, B.; Mechenich, M. F.; Stefanova, I.; Henderson, A.; Donnelly, J. P.

    2007-12-01

    Ongoing climate trends will likely alter how forest ecosystems produce important goods and services, in part, by changing ecosystem responses to disturbances, such as fires and land-use. Disturbances induce forest succession and thus dramatically change the flow of water and nutrients through a given ecosystem. However, long-term ecosystem responses to disturbance, especially regarding nutrient pools and cycling rates, are poorly documented, and less is known about the effects of century-scale climate trends on these responses especially with respect to moisture. Here, we show biogeochemical responses to repeated (>20) episodes of disturbance and succession in a single ecosystem under a range of climatic conditions over 2000 years. Our lake sediment record shows regular fluctuations in the flux of base cations and other macronutrients from lodgepole pine ( Pinus contorta) forests in northern Colorado following catastrophic stand-replacing fires. Post-fire elemental fluctuations are consistent with ecosystem theory regarding the re-equilibration of biomass and nutrient pools during succession, but show systematic variation that has been previously undocumented. The time span of post-fire re-equilibration correlates positively with measures of fire severity, which is consistent with hypotheses that seed dispersal and soil recovery likely slow re-growth after large or severe fires. Likewise, dry conditions during the Medieval Climatic Anomaly (MCA, 1200-500 yrs BP) altered elemental fluctuations and, thus, generated post-fire pulses of lake eutrophication that were not evident during other periods. The interaction of climate and disturbance, therefore, has important consequences for ecosystem function and services, including the quality of aquatic environments.

  4. Soil organic matter cycling in novel and natural boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Norris, C. E.; Mercier Quideau, S.

    2013-12-01

    The uplands of the western boreal forest of Canada are characterized by a mosaic of pure and mixed stands of aspen (Populus tremuloides Michx.) and spruce (Picea glauca (Moench) Voss). In addition to natural ecosystems, the region is now home to novel ecosystems; i.e., ecosystems composed of reclaimed stands formed from trees planted on constructed anthropogenic soils. To understand potential differences in functioning of these novel ecosystems, we must first better understand the functioning of their natural counterparts. Here we present results on both the characterization and cycling of soil organic matter in novel and natural ecosystems found in the Athabasca oil sands region. Soil organic matter from 42 long term monitoring sites was evaluated for long chain (≥ C21) n-alkane composition. The survey showed that n-alkanes were more concentrated and had distinct signatures in natural compared to novel ecosystems. Mineral soils from reclaimed stands showed a distinct microbial community structure from natural aspen and spruce stands, as was demonstrated using phospholipid fatty acids (PLFAs) as microbial biomarkers following addition of 13C-glucose in a laboratory incubation. Further probing by compound specific analysis of the 13C-enriched PLFAs determined that microbial incorporation of 13C-glucose was different among soils. In a field incubation using 15N labeled aspen litter added to the forest floor of reclaimed, harvested and mature natural aspen stands, the microbial community readily incorporated the tracer and nitrogen was cycled to the above-ground vegetation on all sites. In addition, the amendment of leaf litter to the forest floor also increased soil moisture and soil microbial biomass on both the reclaimed and harvested sites. Utilizing stable isotope tracers in addition to a multi-faceted experimental approach has provided insightful results on the development of soil biogeochemical cycling in novel ecosystems.

  5. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

    NASA Technical Reports Server (NTRS)

    Mazurek, Monica A.; Cofer, Wesley R., III; Levine, Joel S.

    1991-01-01

    During the boreal forest burn studied, the ambient concentrations for the particle carbon smoke aerosol are highest for the full-fire burn conditions and vary significantly throughout the burn. Collection strategies must accordingly define ranges in the smoke aerosol concentrations produced. While the highest elemental C concentrations are observed during full-fire conditions, the great majority of smoke aerosol particles are in the form of organic C particles irrespective of fire temperature. The formation of organic C light-scattering particles was a significant process in the burn studied.

  6. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem.

    PubMed

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-03-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.

  7. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem

    NASA Astrophysics Data System (ADS)

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-03-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models.

  8. Differential controls on soil carbon density and mineralization among contrasting forest types in a temperate forest ecosystem

    PubMed Central

    You, Ye-Ming; Wang, Juan; Sun, Xiao-Lu; Tang, Zuo-Xin; Zhou, Zhi-Yong; Sun, Osbert Jianxin

    2016-01-01

    Understanding the controls on soil carbon dynamics is crucial for modeling responses of ecosystem carbon balance to global change, yet few studies provide explicit knowledge on the direct and indirect effects of forest stands on soil carbon via microbial processes. We investigated tree species, soil, and site factors in relation to soil carbon density and mineralization in a temperate forest of central China. We found that soil microbial biomass and community structure, extracellular enzyme activities, and most of the site factors studied varied significantly across contrasting forest types, and that the associations between activities of soil extracellular enzymes and microbial community structure appeared to be weak and inconsistent across forest types, implicating complex mechanisms in the microbial regulation of soil carbon metabolism in relation to tree species. Overall, variations in soil carbon density and mineralization are predominantly accounted for by shared effects of tree species, soil, microclimate, and microbial traits rather than the individual effects of the four categories of factors. Our findings point to differential controls on soil carbon density and mineralization among contrasting forest types and highlight the challenge to incorporate microbial processes for constraining soil carbon dynamics in global carbon cycle models. PMID:26925871

  9. Avian, salamander, and forest floor mercury concentrations increase with elevation in a terrestrial ecosystem.

    PubMed

    Townsend, Jason M; Driscoll, Charles T; Rimmer, Christopher C; McFarland, Kent P

    2014-01-01

    High-elevation ecosystems of the northeastern United States are vulnerable to deposition and environmental accumulation of atmospheric pollutants, yet little work has been done to assess mercury (Hg) concentrations in organisms occupying montane ecosystems. The authors present data on Hg concentrations in ground-foraging insectivorous songbirds, a terrestrial salamander, and forest floor horizons sampled along a forested elevational gradient from 185 m to 1273 m in the Catskill Mountains, New York, USA. Mean Hg concentrations in Catharus thrushes and the salamander Plethodon cinereus increased with elevation, as did Hg concentrations in all forest floor horizons. Mean Hg concentrations in organic soils at approximately 1200 m elevation (503.5 ± 17.7 ng/g, dry wt) were 4.4-fold greater than those at approximately 200 m. Montane ecosystems of the northeastern United States, and probably elsewhere, are exposed to higher levels of atmospheric Hg deposition as reflected in accumulation patterns in the forest floor and associated high-elevation fauna. This information can be used to parameterize and test Hg transport and bioaccumulation models of landscape-specific patterns and may serve as a monitoring tool for decision makers considering future controls on Hg emissions. Further investigation is needed into the potential effects of increased Hg concentrations on high-elevation fauna.

  10. Habitat creation and biodiversity maintenance in mangrove forests: teredinid bivalves as ecosystem engineers

    PubMed Central

    Michie, Laura; Taylor, Ben W.

    2014-01-01

    Substantial amounts of dead wood in the intertidal zone of mature mangrove forests are tunnelled by teredinid bivalves. When the tunnels are exposed, animals are able to use tunnels as refuges. In this study, the effect of teredinid tunnelling upon mangrove forest faunal diversity was investigated. Mangrove forests exposed to long emersion times had fewer teredinid tunnels in wood and wood not containing teredinid tunnels had very few species and abundance of animals. However, with a greater cross-sectional percentage surface area of teredinid tunnels, the numbers of species and abundance of animals was significantly higher. Temperatures within teredinid-attacked wood were significantly cooler compared with air temperatures, and animal abundance was greater in wood with cooler temperatures. Animals inside the tunnels within the wood may avoid desiccation by escaping the higher temperatures. Animals co-existing in teredinid tunnelled wood ranged from animals found in terrestrial ecosystems including centipedes, crickets and spiders, and animals found in subtidal marine ecosystems such as fish, octopods and polychaetes. There was also evidence of breeding within teredinid-attacked wood, as many juvenile individuals were found, and they may also benefit from the cooler wood temperatures. Teredinid tunnelled wood is a key low-tide refuge for cryptic animals, which would otherwise be exposed to fishes and birds, and higher external temperatures. This study provides evidence that teredinids are ecosystem engineers and also provides an example of a mechanism whereby mangrove forests support intertidal biodiversity and nurseries through the wood-boring activity of teredinids. PMID:25276505

  11. The environmental behaviour of polychlorinated phenols and its relevance to cork forest ecosystems: a review.

    PubMed

    McLellan, Iain; Carvalho, Mariana; Silva Pereira, Cristina; Hursthouse, Andrew; Morrison, Calum; Tatner, Paul; Martins, Isabel; San Romão, M Vitória; Leitão, Maria

    2007-10-01

    Pentachlorophenol (PCP) has been used as a herbicide, biocide and preservative worldwide since the 1930s and as a result, extensive and prolonged contamination exists. The environmental impact increases when its many degradation products are taken into consideration. A number of chloroanisols and their related chlorophenols have been found in cork slabs collected from Portuguese oak tree forests before stopper manufacturing, and contamination by PCP and polychlorinated anisole (PCA) has been detected in Canadian forests. It is suggested that the use of polychlorinated phenols, in particular PCP, is thought to be a cause of the cork taint problem in wine, a major socio-economic impact not only for industry but on sensitive and highly biodiverse ecosystems. It also highlights particular issues relating to the regional regulation of potentially toxic chemicals and global economics world wide. To fully understand the impact of contamination sources, the mechanisms responsible for the fate and transport of PCP and its degradation products and assessment of their environmental behaviour is required. This review looks at the current state of knowledge of soil sorption, fate and bioavailability and identifies the challenges of degradation product identification and the contradictory evidence from field and laboratory observations. The need for a systematic evaluation of PCP contamination in relation to cork forest ecosystems and transfer of PCP between trophic levels is emphasised by discrepancies in bioaccumulation and toxicity. This is essential to enable long term management of not only transboundary contaminants, but also the sustainable management of socially and economically important forest ecosystems.

  12. Continental estimates of forest cover and forest cover changes in the dry ecosystems of Africa between 1990 and 2000

    PubMed Central

    Bodart, Catherine; Brink, Andreas B; Donnay, François; Lupi, Andrea; Mayaux, Philippe; Achard, Frédéric

    2013-01-01

    Aim This study provides regional estimates of forest cover in dry African ecoregions and the changes in forest cover that occurred there between 1990 and 2000, using a systematic sample of medium-resolution satellite imagery which was processed consistently across the continent. Location The study area corresponds to the dry forests and woodlands of Africa between the humid forests and the semi-arid regions. This area covers the Sudanian and Zambezian ecoregions. Methods A systematic sample of 1600 Landsat satellite imagery subsets, each 20 km × 20 km in size, were analysed for two reference years: 1990 and 2000. At each sample site and for both years, dense tree cover, open tree cover, other wooded land and other vegetation cover were identified from the analysis of satellite imagery, which comprised multidate segmentation and automatic classification steps followed by visual control by national forestry experts. Results Land cover and land-cover changes were estimated at continental and ecoregion scales and compared with existing pan-continental, regional and local studies. The overall accuracy of our land-cover maps was estimated at 87%. Between 1990 and 2000, 3.3 million hectares (Mha) of dense tree cover, 5.8 Mha of open tree cover and 8.9 Mha of other wooded land were lost, with a further 3.9 Mha degraded from dense to open tree cover. These results are substantially lower than the 34 Mha of forest loss reported in the FAO's 2010 Global Forest Resources Assessment for the same period and area. Main conclusions Our method generates the first consistent and robust estimates of forest cover and change in dry Africa with known statistical precision at continental and ecoregion scales. These results reduce the uncertainty regarding vegetation cover and its dynamics in these previously poorly studied ecosystems and provide crucial information for both science and environmental policies. PMID:23935237

  13. Forest floor depth mediates understory vigor in xeric Pinus palustris ecosystems.

    PubMed

    Hiers, J Kevin; O'Brien, Joseph J; Will, Rodney E; Mitchell, Robert J

    2007-04-01

    Longleaf pine (Pinus palustris) woodlands and savannas are among the most frequently burned ecosystems in the world with fire return intervals of 1-10 years. This fire regime has maintained high levels of biodiversity in terms of both species richness and endemism. Land use changes have reduced the area of this ecosystem by >95%, and inadequate fire frequencies threaten many of the remnants today. In the absence of frequent fire, rapid colonization of hardwoods and shrubs occurs, and a broad-leaved midstory develops. This midstory encroachment has been the focus of much research and management concern, largely based on the assumption that the midstory reduces understory plant diversity through direction competition via light interception. The general application of this mechanism of degradation is questionable, however, because midstory density, leaf area, and hardwood species composition vary substantially along a soil moisture gradient from mesic to extremely xeric sites. Reanalysis of recently reported data from xeric longleaf pine communities suggests that the development of the forest floor, a less conspicuous change in forest structure, might cause a decline in plant biodiversity when forests remain unburned. We report here a test of the interactions among fire, litter accumulation, forest floor development, and midstory canopy density on understory plant diversity. Structural equation modeling showed that within xeric sites, forest floor development was the primary factor explaining decreased biodiversity. The only effects of midstory development on biodiversity were those mediated through forest floor development. Boundary line analysis of functional guilds of understory plants showed sensitivity to even minor development of the forest floor in the absence of fire. These results challenge the prevailing management paradigm and suggest that within xeric longleaf pine communities, the primary focus of managed fire regime should be directed toward the

  14. Thermal Imaging of Forest Canopy Temperatures: Relationships with Biological and Biophysical Drivers and Ecosystem Fluxes

    NASA Astrophysics Data System (ADS)

    Still, C. J.; Kim, Y.; Hanson, C. V.; Law, B. E.; Kwon, H.; Schulze, M.; Pau, S.; Detto, M.

    2015-12-01

    Temperature is a primary environmental control on plant processes at a range of spatial and temporal scales, affecting enzymatic reactions, ecosystem biogeochemistry, and species distributions. Although most focus is on air temperature, the radiative or skin temperature of plants is more relevant. Canopy skin temperature dynamics reflect biophysical, physiological, and anatomical characteristics and interactions with environmental drivers, and can be used to examine forest responses to stresses like droughts and heat waves. Direct measurements of plant canopy temperatures using thermocouple sensors have been challenging and offer limited information. Such measurements are usually conducted over short periods of time and a limited spatial extent of the canopy. By contrast, thermal infrared (TIR) imaging allows for extensive temporal and spatial measurement of canopy temperature regimes. We present results of TIR imaging of forest canopies at a range of well-studied forest sites in the United States and Panama. These forest types include temperate rainforests, a semi­arid pine forest, and a semi­deciduous tropical forest. Canopy temperature regimes at these sites are highly variable spatially and temporally and display frequent departures from air temperature, particularly during clear sky conditions. Canopy tissue temperatures are often warmer (daytime) and colder (nighttime) than air temperature, and canopy structure seems to have a large influence on the thermal regime. Additionally, comparison of canopy temperatures to eddy covariance fluxes of carbon dioxide, water vapor, and energy reveals relationships not apparent using air temperature. Initial comparisons between our forest canopy temperatures and remotely sensed skin temperature using Landsat and MODIS data show reasonably good agreement. We conclude that temporal and spatial changes in canopy temperature and its relationship to biological and environmental factors can improve our understanding of how

  15. Changes in the forest ecosystems in areas impacted by aridization in south-western Romania

    PubMed Central

    2014-01-01

    Background In the past few decades, global climate change has accentuated the intensification of aridization in South-Western Romania, with direct and indirect consequences on the quality of forest ecosystems. In addition to qualitative deterioration, the quantitative changes brought about by intensive anthropic deforestation have created the conditions for a decline in the size of forest areas on vast tracts of land. The paper aims to analyze the qualitative and quantitative changes in the forest ecosystems in South-Western Romania, changes due to the synergic context of the global climate changes and the anthropic pressures of the past three decades. In order to capture the evolution of aridization in the study area, specific aridization indexes have been calculated, such as the De Martonne index and the UNEP aridity index. 1990 and 2011 satellite images have been used in order to quantify the qualitative changes. Results The results obtained indicated that, in the past two decades, the quality of the biomass declined as a result of the increase in the climatic aridity conditions (De Martonne si UNEP aridity index, indicating in the last decades, annual values under 15 mm/°C, and under 0.5 mm/mm, that means that the values situated under these thresholds, describe arid and semi-arid climate conditions). Also, the uncontrolled logging across vast surfaces caused the loss of forest ecosystems by 7% in the overall study area, during the last three decades. Conclusions The severe effects of aridization meant, first of all, a significant decline in the quality of the ecosystem services supplied by forests. In the absence of viable actions to correct the present situation, the extremely undesirable consequences of an ecological and social nature will arise in the near future. PMID:24393389

  16. Ecosystem carbon storage does not vary with mean annual temperature in Hawaiian tropical montane wet forests.

    PubMed

    Selmants, Paul C; Litton, Creighton M; Giardina, Christian P; Asner, Gregory P

    2014-09-01

    Theory and experiment agree that climate warming will increase carbon fluxes between terrestrial ecosystems and the atmosphere. The effect of this increased exchange on terrestrial carbon storage is less predictable, with important implications for potential feedbacks to the climate system. We quantified how increased mean annual temperature (MAT) affects ecosystem carbon storage in above- and belowground live biomass and detritus across a well-constrained 5.2 °C MAT gradient in tropical montane wet forests on the Island of Hawaii. This gradient does not systematically vary in biotic or abiotic factors other than MAT (i.e. dominant vegetation, substrate type and age, soil water balance, and disturbance history), allowing us to isolate the impact of MAT on ecosystem carbon storage. Live biomass carbon did not vary predictably as a function of MAT, while detrital carbon declined by ~14 Mg of carbon ha(-1) for each 1 °C rise in temperature - a trend driven entirely by coarse woody debris and litter. The largest detrital pool, soil organic carbon, was the most stable with MAT and averaged 48% of total ecosystem carbon across the MAT gradient. Total ecosystem carbon did not vary significantly with MAT, and the distribution of ecosystem carbon between live biomass and detritus remained relatively constant across the MAT gradient at ~44% and ~56%, respectively. These findings suggest that in the absence of alterations to precipitation or disturbance regimes, the size and distribution of carbon pools in tropical montane wet forests will be less sensitive to rising MAT than predicted by ecosystem models. This article also provides needed detail on how individual carbon pools and ecosystem-level carbon storage will respond to future warming.

  17. Ecosystem N distribution and δ15N during a century of forest regrowth after agricultural abandonment

    USGS Publications Warehouse

    Compton, J.E.; Hooker, T.D.; Perakis, S.S.

    2007-01-01

    Stable isotope ratios of terrestrial ecosystem nitrogen (N) pools reflect internal processes and input–output balances. Disturbance generally increases N cycling and loss, yet few studies have examined ecosystem δ15N over a disturbance-recovery sequence. We used a chronosequence approach to examine N distribution and δ15N during forest regrowth after agricultural abandonment. Site ages ranged from 10 to 115 years, with similar soils, climate, land-use history, and overstory vegetation (white pine Pinus strobus). Foliar N and δ15N decreased as stands aged, consistent with a progressive tightening of the N cycle during forest regrowth on agricultural lands. Over time, foliar δ15N became more negative, indicating increased fractionation along the mineralization–mycorrhizal–plant uptake pathway. Total ecosystem N was constant across the chronosequence, but substantial internal N redistribution occurred from the mineral soil to plants and litter over 115 years (>25% of ecosystem N or 1,610 kg ha−1). Temporal trends in soil δ15N generally reflected a redistribution of depleted N from the mineral soil to the developing O horizon. Although plants and soil δ15N are coupled over millennial time scales of ecosystem development, our observed divergence between plants and soil suggests that they can be uncoupled during the disturbance-regrowth sequence. The approximate 2‰ decrease in ecosystem δ15N over the century scale suggests significant incorporation of atmospheric N, which was not detected by traditional ecosystem N accounting. Consideration of temporal trends and disturbance legacies can improve our understanding of the influence of broader factors such as climate or N deposition on ecosystem N balances and δ15N.

  18. Climate change, forest management and nitrogen deposition influence on carbon sequestration in forest ecosystems in Russia: simulation modelling approach

    NASA Astrophysics Data System (ADS)

    Komarov, Alexander; Kudeyarov, Valery; Shanin, Vladimir

    2014-05-01

    Russian land ecosystems occupy more than 1/9th global land area. Therefore its carbon budget is an essential contribution to the global carbon budget. The first rough estimate of carbon balance on Russian territory was made on comparison data on total soil respiration (Kudeyarov et. al., 1995) and NPP calculated on data on biological productivity of different ecosystems over Russia. The carbon balance was evaluated as a C-sink. Further estimates of Russian C budget by V.Kudeyarov et al., (2007) and I.Kurganova et al., (2010) were more correct and included soil microbial flux, and non-respiratory processes: fossil fuel, agriculture, forest fires and post-fire emissions, insect damage, etc. According to estimates the total C-sink of Russian territory for early nineties was about -0.8-1.0 Pg C per year. The later IIASA account developed by A.Shvidenko et al. (2010) has provided current estimates of C fluxes and storages in Russia and showed that its terrestrial ecosystems served as a net carbon sink of -0.5-0.7 PgC yr-1 during the last decade. Taking into account big uncertainties of determination of carbon balance constituents one can say that results by IIASA and our Institute are rather close. Resulting effect of two processes (sequestration and CO2 emission) can be analysed by mathematical modelling only. Corresponding system of models of organic matter dynamics in forest ecosystems EFIMOD was developed in our Institute last decade and applied in Russia and other countries for evaluation of impacts of climate changes, forest management and forest fires. The comparative simulations of carbon and nitrogen dynamics in the mixed forest ecosystems of Central Russia from different climatic zones and site conditions have been made. Three large forest areas with the total square of about 17,000 km2 distinct in environmental conditions were chosen. We used the data of the forest inventory for model initialization. Four simulation scenarios (without disturbances, with

  19. Carbonaceous aerosols from prescribed burning of a boreal forest ecosystem

    SciTech Connect

    Mazurek, M.A. ); Cofer, W.R. III; Levine, J.S. . Langley Research Center)

    1990-10-01

    The identity and ambient mass concentrations of radiatively important carbonaceous aerosols were measured for a boreal forest prescribed burn conducted in northern Ontario, CAN in August 1989. Nonsize-segregated airborne particles were collected for smoldering-fire and full-fire conditions using a helicopter sampling platform. Total carbon (TC), organic carbon (OC) and elemental carbon (EC) were measured. Smoke plume mass concentrations of the OC and EC particles were greatest for full-fire conditions and had ranges of 1.560 to 2.160 mg/m{sup {minus}1} (OC) and 0.120 to 0.160 mg/m{sup {minus}3} (EC) with OC:EC ratios of 10 to 18, respectively. Smoldering fire conditions showed smoke plume OC and EC levels of 0.570--1.030 mg/m{sup {minus}3} (OC) and 0.006--0.050 mg/m{sup {minus}3} (EC) and much higher ratios of OC:EC (21 to 95). These aerosol data indicate the formation of EC particles is greatest during full-fire combustion of boreal forest material relative to smoldering combustion. However, EC particles comprise a minor fraction of the particulate carbon smoke aerosols for both full-fire and smoldering conditions; the major component of carbonaceous smoke aerosols emitted during the prescribed burn is OC. Overall, the OC and EC in-plume smoke aerosol data show nonuniform production of these particles during various stages of the prescribed burn, and major differences in the type of carbonaceous aerosol that is generated (OC versus EC).

  20. Multitemporal diurnal AVIRIS images of a forested ecosystem

    NASA Technical Reports Server (NTRS)

    Ustin, Susan L.; Smith, Milton O.; Adams, John B.

    1992-01-01

    Both physiological and ecosystem structural information may be derived from diurnal images. Structural information may be inferred from changes in canopy shadows between images and from changes in spectral composition due to changes in proportions of subpixel mixing resulting from the differences in sun/view angles. Physiological processes having diurnal scales also may be measurable if a stable basis for spectral comparison can be established. Six diurnal images of an area east of Mt. Shasta, CA were acquired on 22 Sep. 1989. This unique diurnal data set provided an opportunity to test the consistency of endmember fractions and residuals. It was expected that shade endmember abundances would show the greatest change as lighting geometry changed and less change in the normalized fractional proportion of other endmembers. Diurnal changes in spectral features related to physiological characteristics may be identifiable as changes in wavelength specific residuals.

  1. Using Lidar and Radar measurements to constrain predictions of forest ecosystem structure and function.

    PubMed

    Antonarakis, Alexander S; Saatchi, Sassan S; Chazdon, Robin L; Moorcroft, Paul R

    2011-06-01

    Insights into vegetation and aboveground biomass dynamics within terrestrial ecosystems have come almost exclusively from ground-based forest inventories that are limited in their spatial extent. Lidar and synthetic-aperture Radar are promising remote-sensing-based techniques for obtaining comprehensive measurements of forest structure at regional to global scales. In this study we investigate how Lidar-derived forest heights and Radar-derived aboveground biomass can be used to constrain the dynamics of the ED2 terrestrial biosphere model. Four-year simulations initialized with Lidar and Radar structure variables were compared against simulations initialized from forest-inventory data and output from a long-term potential-vegtation simulation. Both height and biomass initializations from Lidar and Radar measurements significantly improved the representation of forest structure within the model, eliminating the bias of too many large trees that arose in the potential-vegtation-initialized simulation. The Lidar and Radar initializations decreased the proportion of larger trees estimated by the potential vegetation by approximately 20-30%, matching the forest inventory. This resulted in improved predictions of ecosystem-scale carbon fluxes and structural dynamics compared to predictions from the potential-vegtation simulation. The Radar initialization produced biomass values that were 75% closer to the forest inventory, with Lidar initializations producing canopy height values closest to the forest inventory. Net primary production values for the Radar and Lidar initializations were around 6-8% closer to the forest inventory. Correcting the Lidar and Radar initializations for forest composition resulted in improved biomass and basal-area dynamics as well as leaf-area index. Correcting the Lidar and Radar initializations for forest composition and fine-scale structure by combining the remote-sensing measurements with ground-based inventory data further improved

  2. Reach-scale effects of riparian forest cover on urban stream ecosystems

    USGS Publications Warehouse

    Roy, A.H.; Faust, C.L.; Freeman, Mary C.; Meyer, J.L.

    2005-01-01

    We compared habitat and biota between paired open and forested reaches within five small streams (basin area 10?20 km2) in suburban catchments (9%?49% urban land cover) in the Piedmont of Georgia, USA. Stream reaches with open canopies were narrower than forested reaches (4.1 versus 5.0 m, respectively). There were no differences in habitat diversity (variation in velocity, depth, or bed particle size) between open and forested reaches. However, absence of local forest cover corresponded to decreased large wood and increased algal chlorophyll a standing crop biomass. These differences in basal food resources translated into higher densities of fishes in open (9.0 individuals?m?2) versus forested (4.9 individuals?m?2) reaches, primarily attributed to higher densities of the herbivore Campostoma oligolepis. Densities of terrestrial invertebrate inputs were higher in open reaches; however, trends suggested higher biomass of terrestrial inputs in forested reaches and a corresponding higher density of terrestrial prey consumed by water column feeding fishes. Reach-scale biotic integrity (macroinvertebrates, salamanders, and fishes) was largely unaffected by differences in canopy cover. In urbanizing areas where catchment land cover drives habitat and biotic quality, management practices that rely exclusively on forested riparian areas for stream protection are unlikely to be effective at maintaining ecosystem integrity.

  3. A case for using Plethodontid salamanders for monitoring biodiversity and ecosystem integrity of North American forests

    USGS Publications Warehouse

    Welsh, H.H.; Droege, S.

    2001-01-01

    Terrestrial salamanders of the family P!ethodontidae have unique attributes that make them excellent indicators of biodiversity and ecosystem integrity in forested habitats. Their longevity, small territory size, site fidelity, sensitivity to natural and anthropogenic perturbations, tendency to occur in high densities, and low sampling costs mean that counts of plethodontid salamanders provide numerous advantages over counts of other North American forest organisms for indicating environmental change. Furthermore, they are tightly linked physiologically to microclimatic and successional processes that influence the distribution and abundance of numerous other hydrophilic but difficult-to-study forest-dwelling plants and animals. Ecosystem processes such as moisture cycling, food-web dynamics, and succession, with their related structural and microclimatic variability, all affect forest biodiversity and have been shown to affect salamander populations as well. We determined the variability associated with sampling for plethodontid salamanders by estimating the coefficient of variation (CV) from available time-series data. The median coefficient of variation indicated that variation in counts of individuals among studies was much lower in plethodonticis (27%) than in lepidoptera (93%), passerine birds (57%), small mammals (69%), or other amphibians (37-46%), which means plethodontid salamanders provide an important statistical advantage over other species for monitoring long-term forest health.

  4. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate

    PubMed Central

    Duan, Kai; Sun, Ge; Sun, Shanlei; Caldwell, Peter V.; Cohen, Erika C.; McNulty, Steven G.; Aldridge, Heather D.; Zhang, Yang

    2016-01-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m−2 yr−1 (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr−1 (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr−1). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services. PMID:27100360

  5. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate

    NASA Astrophysics Data System (ADS)

    Duan, Kai; Sun, Ge; Sun, Shanlei; Caldwell, Peter V.; Cohen, Erika C.; McNulty, Steven G.; Aldridge, Heather D.; Zhang, Yang

    2016-04-01

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m‑2 yr‑1 (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr‑1 (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr‑1). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services.

  6. Divergence of ecosystem services in U.S. National Forests and Grasslands under a changing climate.

    PubMed

    Duan, Kai; Sun, Ge; Sun, Shanlei; Caldwell, Peter V; Cohen, Erika C; McNulty, Steven G; Aldridge, Heather D; Zhang, Yang

    2016-04-21

    The 170 National Forests and Grasslands (NFs) in the conterminous United States are public lands that provide important ecosystem services such as clean water and timber supply to the American people. This study investigates the potential impacts of climate change on two key ecosystem functions (i.e., water yield and ecosystem productivity) using the most recent climate projections derived from 20 Global Climate Models (GCMs) of the Coupled Model Intercomparison Project phase 5 (CMIP5). We find that future climate change may result in a significant reduction in water yield but an increase in ecosystem productivity in NFs. On average, gross ecosystem productivity is projected to increase by 76 ~ 229 g C m(-2) yr(-1) (8% ~ 24%) while water yield is projected to decrease by 18 ~ 31 mm yr(-1) (4% ~ 7%) by 2100 as a result of the combination of increased air temperature (+1.8 ~ +5.2 °C) and precipitation (+17 ~ +51 mm yr(-1)). The notable divergence in ecosystem services of water supply and carbon sequestration is expected to intensify under higher greenhouse gas emission and associated climate change in the future, posing greater challenges to managing NFs for both ecosystem services.

  7. Contrasting Patterns of Carbon Flux and Storage in Pine Forest Ecosystems of the Atlantic Coastal Plain: Implications for Ecosystem Restoration and Climate Change Mitigation.

    NASA Astrophysics Data System (ADS)

    Mitchell, S. R.; Christensen, N.; Cohen, S.; Cunningham, P.

    2015-12-01

    Forest ecosystems in the Southeastern US have high rates of productivity but are underutilized as a medium for the mitigation of atmospheric CO2. In the lower Atlantic coastal plain, three pine species (longleaf [Pinus palustris], loblolly [P. taeda] and pond [P. serotina]) are the dominant overstory trees in a variety of wetland and upland ecosystems. These forest types can exist in close proximity throughout coastal plain landscapes, but exhibit contrasting patterns of productivity, pyrogenic C emissions, and mortality, thereby creating contrasting patterns of C assimilation and long-term C storage. Here, we combine field-based estimates of forest C storage and pyrogenic C emissions with LiDAR-based estimates of forest canopy heights in three contrasting forest ecosystems to 1) model their respective patterns of forest growth, mortality, and decomposition, 2) estimate the contribution of pyrogenic C fluxes to the ecosystem C budget, 3) estimate their potential upper bounds of forest C storage, and 4) model the impacts of current forest management practices and disturbance regimes on long-term forest C storage. Our results suggest that even though longleaf pine forests store comparatively little C in soil or belowground biomass, these forests nevertheless have the highest capacity for long-term C storage, in part due to their longevity. By contrast, while pond pine ecosystems have the highest capacity for long-term belowground C storage, they also have the lowest capacity for long-term aboveground C storage, one that is rarely achieved due to infrequent, high-severity disturbance regimes. Loblolly pine forests, while capable of higher growth rates than either longleaf or pond pine when in early stages of succesion, lack the long-term C storage capabilities of longleaf pine due to earlier senescence. Pyrogenic C emissions in these ecosystems are dominated by the combustion of ground and duff materials and occur over timescales ranging from rapid combustion in fire

  8. Does complex terrain matter for global terrestrial ecosystem models? Forest ecosystem dynamics in the White Mountains, NH. (Invited)

    NASA Astrophysics Data System (ADS)

    Dietze, M. C.; Richardson, A. D.; Moorcroft, P. R.

    2010-12-01

    Environmental scientists have long recognized that vegetation varies consistently at a landscape-scale due to variation in soils, hydrology, and topography. We expect that this variation to interact with climate change in complex ways, potentially allowing some species to persist in refugia while shifting other species to locations that may be edaphically unfavorable. Despite the recognized importance of this variation, it has not been incorporated into global and regional scale models because this heterogeneity occurs at a finer spatial scale than can be captured explicitly by refining model resolution. Rather than represent landscape-scale variability explicitly, we develop a spatially implicit approach to capture variation in soils, lateral hydrologic flow, and the effects of topography on microclimate and radiation interception. This scheme is incorporated in the Ecosystem Demography model. We tested this approach by first calibrating the model to forest inventory data and eddy-covariance fluxes of carbon, water, and energy from the Bartlett Experimental Forest in central NH and then validating it against 40+ years of vegetation and hydrology data from the Hubbard Brook Ecosystem Study, located 40km in forests of similar composition. When applied to Hubbard Brook the model is able to capture watershed streamflow at monthly to interannual scales and the variation in growth rates with topography, soils, and hydrology, and reproduces observed NPP during the forest growth phase. Growth rates were overestimated during the latter portion of the record, likely due to the cumulative impacts of acid rain which are not yet accounted for in the model. By sequentially switching off each source of edaphic variation, we find that the effect of elevation on microclimate has the greatest impact on the within-watershed distribution of NEE and NPP. The effects of slope and aspect on radiation are strongest at mid-elevation while lateral hydrology is most important on ridges and

  9. Chemical attributes of some clouds amid a forest ecosystem's trees

    USGS Publications Warehouse

    DeFelice, Thomas P.

    2002-01-01

    Simultaneous physical and chemical characteristics of clouds amid and above the trees of a montane forest, located about 3.3 km southwest of Mt. Mitchell, NC, were collected between 13 and 22 June 1993. This paper summarizes the chemical characteristics of the cloud droplets amid the trees. The ionic composition and pH of the analyzed amid-canopy cloud water samples are generally consistent with those of previous above-canopy cloud water samples obtained at this site. Magnesium, sodium, and calcium are highly correlated to each other amid the canopy as compared to above the canopy. Above-canopy and amid-canopy cloud-only episodes, with concurrent event-averaged cloud water pH values at or below 3.1, generally contain more magnesium, sodium, and calcium in the amid-canopy cloud water samples compared to concurrent above-canopy cloud water samples. The observed chemical differences between the amid-canopy cloud and the above- canopy cloud suggest an unhealthier environment for the tree canopy when the cloud water traversing this site has a pH value at or below 3.1. The predominant ion deposition fluxes were calculated to provide preliminary data for studies designed to explicitly quantify how the chemical composition of cloud water affects tree health. ?? 2002 Elsevier Science B.V. All rights reserved.

  10. Near isometric biomass partitioning in forest ecosystems of China.

    PubMed

    Hui, Dafeng; Wang, Jun; Shen, Weijun; Le, Xuan; Ganter, Philip; Ren, Hai

    2014-01-01

    Based on the isometric hypothesis, belowground plant biomass (MB) should scale isometrically with aboveground biomass (MA) and the scaling exponent should not vary with environmental factors. We tested this hypothesis using a large forest biomass database collected in China. Allometric scaling functions relating MB and MA were developed for the entire database and for different groups based on tree age, diameter at breast height, height, latitude, longitude or elevation. To investigate whether the scaling exponent is independent of these biotic and abiotic factors, we analyzed the relationship between the scaling exponent and these factors. Overall MB was significantly related to MA with a scaling exponent of 0.964. The scaling exponent of the allometric function did not vary with tree age, density, latitude, or longitude, but varied with diameter at breast height, height, and elevation. The mean of the scaling exponent over all groups was 0.986. Among 57 scaling relationships developed, 26 of the scaling exponents were not significantly different from 1. Our results generally support the isometric hypothesis. MB scaled near isometrically with MA and the scaling exponent did not vary with tree age, density, latitude, or longitude, but increased with tree size and elevation. While fitting a single allometric scaling relationship may be adequate, the estimation of MB from MA could be improved with size-specific scaling relationships.

  11. Revegetation standards for floodplain forest ecosystems in western Washington, USA

    SciTech Connect

    Zamora, B.

    1996-12-31

    Mining activity within floodplain landforms of western Washington, USA, presents unique problems in terms of approaches to revegetation and the success standards to be use to quantitatively evaluate revegetation success. Persistent historical disturbance of floodplain areas of the region has left little undisturbed natural vegetation to use as reference sites for development of success standards. A strategy is proposed for use of an ecological model of succession within floodplain vegetation to both identify revegetation options and provide a quantifiable and ecologically dynamic framework of success standards for revegetation evaluation. The floodplain forest moasic of mined lands in western Washington is a combination of (1) aquatic sites of open surface, impounded or flowing waters, (2) minerotrophic wetlands, and (3) xeroriparian sites between wetlands and uplands. Seven distinct and persistent plant communities of three community types are present are common. These physiognomic groupings successionally linked as habitats change from one flooding regime to another. Remenant stands of floodplain vegetation were used to construct a successional model which will provide for revegetation guidelines and a framework of success standards.

  12. Near isometric biomass partitioning in forest ecosystems of China.

    PubMed

    Hui, Dafeng; Wang, Jun; Shen, Weijun; Le, Xuan; Ganter, Philip; Ren, Hai

    2014-01-01

    Based on the isometric hypothesis, belowground plant biomass (MB) should scale isometrically with aboveground biomass (MA) and the scaling exponent should not vary with environmental factors. We tested this hypothesis using a large forest biomass database collected in China. Allometric scaling functions relating MB and MA were developed for the entire database and for different groups based on tree age, diameter at breast height, height, latitude, longitude or elevation. To investigate whether the scaling exponent is independent of these biotic and abiotic factors, we analyzed the relationship between the scaling exponent and these factors. Overall MB was significantly related to MA with a scaling exponent of 0.964. The scaling exponent of the allometric function did not vary with tree age, density, latitude, or longitude, but varied with diameter at breast height, height, and elevation. The mean of the scaling exponent over all groups was 0.986. Among 57 scaling relationships developed, 26 of the scaling exponents were not significantly different from 1. Our results generally support the isometric hypothesis. MB scaled near isometrically with MA and the scaling exponent did not vary with tree age, density, latitude, or longitude, but increased with tree size and elevation. While fitting a single allometric scaling relationship may be adequate, the estimation of MB from MA could be improved with size-specific scaling relationships. PMID:24466149

  13. An Early Warning System for Identification and Monitoring of Disturbances to Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Marshall, A. A.; Hoffman, F. M.; Kumar, J.; Hargrove, W. W.; Spruce, J.; Mills, R. T.

    2011-12-01

    Forest ecosystems are susceptible to damage due to threat events like wildfires, insect and disease attacks, extreme weather events, land use change, and long-term climate change. Early identification of such events is desired to devise and implement a protective response. The mission of the USDA Forest Service is to sustain the health, diversity, and productivity of the nation's forests. However, limited resources for aerial surveys and ground-based inspections are insufficient for monitoring the large areas covered by the U.S. forests. The USDA Forest Service, Oak Ridge National Laboratory, and NASA Stennis Space Center are developing an early warning system for the continuous tracking and long-term monitoring of disturbances and responses in forest ecosystems using high resolution satellite remote sensing data. Geospatiotemporal data mining techniques were developed and applied to normalized difference vegetation index (NDVI) products derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) MOD 13 data at 250 m resolution on eight day intervals. Representative phenologically similar regions, or phenoregions, were developed for the conterminous United States (CONUS) by applying a k-means clustering algorithm to the NDVI data spanning the full eight years of the MODIS record. Annual changes in the phenoregions were quantitatively analyzed to identify the significant changes in phenological behavior. This methodology was successfully applied for identification of various forest disturbance events, including wildfire, tree mortality due to Mountain Pine Beetle, and other insect infestation and diseases, as well as extreme events like storms and hurricanes in the United States. Where possible, the results were validated and quantitatively compared with aerial and ground-based survey data available from different agencies. This system was able to identify most of the disturbances reported by aerial and ground-based surveys, and it also identified

  14. Effects of Repeated Fires in the Forest Ecosystems of the Zabaikalye Region, Southern Siberia

    NASA Astrophysics Data System (ADS)

    Kukavskaya, E.; Buryak, L. V.; Conard, S. G.; Petkov, A.; Barrett, K.; Kalenskaya, O. P.; Ivanova, G.

    2014-12-01

    Fire is the main ecological disturbance controlling forest development in the boreal forests of Siberia and contributing substantially to the global carbon cycle. The warmer and dryer climate observed recently in the boreal forests is considered to be responsible for extreme fire weather, resulting in higher fire frequency, larger areas burned, and an increase of fire severity. Because of the increase of fire activity, boreal forests in some regions may not be able to reach maturity before they re-burn, which means less carbon will be stored in the ecosystem and more will remain in the atmosphere. Moreover, if one fire occurs within a few years of another, some stands will not re-grow at all, and even more carbon will accumulate in the atmosphere. Zabaikalye region located in the south of Siberia is characterized by the highest fire activity in Russia. With a use of the satellite-based fire product we found that there are about 7.0 million hectares in the region burned repeatedly during the last decade. We have investigated a number of sites in-situ in light-coniferous (Scots pine and larch) forests and evaluated the impacts of repeated fires on fuel loads, carbon emissions, and tree regeneration. Substantial decrease of carbon stocks, change of the vegetation structure and composition, and soil erosion were observed in many areas disturbed by repeated fires. At drier sites located in the southern regions repeated fires prohibited successful regeneration and resulted in forest conversion to grassland. Detection and monitoring of changes in the areas of Siberia where repeated fires have caused a major shift in ecosystem structure and function is required for the development of sustainable forest management strategies to mitigate climate change. The research was supported by NASA LCLUC Program.

  15. Global patterns and predictors of stem CO2 efflux in forest ecosystems.

    PubMed

    Yang, Jinyan; He, Yujie; Aubrey, Doug P; Zhuang, Qianlai; Teskey, Robert O

    2016-04-01

    Stem CO2 efflux (ES) plays an important role in the carbon balance of forest ecosystems. However, its primary controls at the global scale are poorly understood and observation-based global estimates are lacking. We synthesized data from 121 published studies across global forest ecosystems and examined the relationships between annual ES and biotic and abiotic factors at individual, biome, and global scales, and developed a global gridded estimate of annual ES . We tested the following hypotheses: (1) Leaf area index (LAI) will be highly correlated with annual ES at biome and global scales; (2) there will be parallel patterns in stem and root CO2 effluxes (RA) in all forests; (3) annual ES will decline with forest age; and (4) LAI coupled with mean annual temperature (MAT) and mean annual precipitation (MAP) will be sufficient to predict annual ES across forests in different regions. Positive linear relationships were found between ES and LAI, as well as gross primary production (GPP), net primary production (NPP), wood NPP, soil CO2 efflux (RS), and RA . Annual ES was correlated with RA in temperate forests after controlling for GPP and MAT, suggesting other additional factors contributed to the relationship. Annual ES tended to decrease with stand age. Leaf area index, MAT and MAP, predicted 74% of variation in ES at global scales. Our statistical model estimated a global annual ES of 6.7 ± 1.1 Pg C yr(-1) over the period of 2000-2012 with little interannual variability. Modeled mean annual ES was 71 ± 43, 270 ± 103, and 420 ± 134 g C m(2) yr(-1) for boreal, temperate, and tropical forests, respectively. We recommend that future studies report ES at a standardized constant temperature, incorporate more manipulative treatments, such as fertilization and drought, and whenever possible, simultaneously measure both aboveground and belowground CO2 fluxes. PMID:26667780

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

    PubMed

    Thom, Dominik; Seidl, Rupert

    2016-08-01

    In many parts of the world forest disturbance regimes have intensified recently, and future climatic changes are expected to amplify this development further in the coming decades. These changes are increasingly challenging the main objectives of forest ecosystem management, which are to provide ecosystem services sustainably to society and maintain the biological diversity of forests. Yet a comprehensive understanding of how disturbances affect these primary goals of ecosystem management is still lacking. We conducted a global literature review on the impact of three of the most important disturbance agents (fire, wind, and bark beetles) on 13 different ecosystem services and three indicators of biodiversity in forests of the boreal, cool- and warm-temperate biomes. Our objectives were to (i) synthesize the effect of natural disturbances on a wide range of possible objectives of forest management, and (ii) investigate standardized effect sizes of disturbance for selected indicators via a quantitative meta-analysis. We screened a total of 1958 disturbance studies published between 1981 and 2013, and reviewed 478 in detail. We first investigated the overall effect of disturbances on individual ecosystem services and indicators of biodiversity by means of independence tests, and subsequently examined the effect size of disturbances on indicators of carbon storage and biodiversity by means of regression analysis. Additionally, we investigated the effect of commonly used approaches of disturbance management, i.e. salvage logging and prescribed burning. We found that disturbance impacts on ecosystem services are generally negative, an effect that was supported for all categories of ecosystem services, i.e. supporting, provisioning, regulating, and cultural services (P < 0.001). Indicators of biodiversity, i.e. species richness, habitat quality and diversity indices, on the other hand were found to be influenced positively by disturbance (P < 0.001). Our analyses thus

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

    PubMed

    Thom, Dominik; Seidl, Rupert

    2016-08-01

    In many parts of the world forest disturbance regimes have intensified recently, and future climatic changes are expected to amplify this development further in the coming decades. These changes are increasingly challenging the main objectives of forest ecosystem management, which are to provide ecosystem services sustainably to society and maintain the biological diversity of forests. Yet a comprehensive understanding of how disturbances affect these primary goals of ecosystem management is still lacking. We conducted a global literature review on the impact of three of the most important disturbance agents (fire, wind, and bark beetles) on 13 different ecosystem services and three indicators of biodiversity in forests of the boreal, cool- and warm-temperate biomes. Our objectives were to (i) synthesize the effect of natural disturbances on a wide range of possible objectives of forest management, and (ii) investigate standardized effect sizes of disturbance for selected indicators via a quantitative meta-analysis. We screened a total of 1958 disturbance studies published between 1981 and 2013, and reviewed 478 in detail. We first investigated the overall effect of disturbances on individual ecosystem services and indicators of biodiversity by means of independence tests, and subsequently examined the effect size of disturbances on indicators of carbon storage and biodiversity by means of regression analysis. Additionally, we investigated the effect of commonly used approaches of disturbance management, i.e. salvage logging and prescribed burning. We found that disturbance impacts on ecosystem services are generally negative, an effect that was supported for all categories of ecosystem services, i.e. supporting, provisioning, regulating, and cultural services (P < 0.001). Indicators of biodiversity, i.e. species richness, habitat quality and diversity indices, on the other hand were found to be influenced positively by disturbance (P < 0.001). Our analyses thus

  18. Light Competition and Carbon Partitioning-Allocation in an improved Forest Ecosystem Model

    NASA Astrophysics Data System (ADS)

    Collalti, Alessio; Santini, Monia; Valentini Valentini, Riccardo

    2010-05-01

    In Italy about 100.000 km2 are covered by forests. This surface is the 30% of the whole national land and this shows how the forests are important both for socio-economic and for environmental aspects. Forests changes affect a delicate balance that involve not only vegetation components but also bio-geochemical cycles and global climate. The knowledge of the amount of Carbon sequestered by forests represents a precious information for their sustainable management in the framework of climate changes. Primary studies in terms of model about this important issue, has been done through Forest Ecosystem Model (FEM), well known and validated as 3PG (Landsberg et Waring, 1997; Sands 2004). It is based on light use efficiency approach at the canopy level. The present study started from the original model 3PG, producing an improved version that uses many of explicit formulations of all relevant ecophysiological processes but makes it able to be applied for natural forests. The mutual interaction of forest growth and light conditions causes vertical and horizontal differentiation in the natural forest mosaic. Only ecophysiological parameters which can be either directly measured or estimates with reasonable certainty are used. The model has been written in C language and has been created considering a tri-dimensional cell structure with different vertical layers depending on the forest type that has to be simulated. This 3PG 'improved' version enable to work on multi-layer and multi-species forests type with cell resolution of one hectare for the typical Italian forest species. The multi-layer version is the result of the implementation and development of Lambert-Beer law for the estimation of intercepted, absorbed and transmitted light through different storeys of the forest. It is possible estimates, for each storey, a Par value (Photosynthetic Active Radiation) through Leaf Area Index (LAI), Light Extinction Coefficient and cell Canopy Cover using a "Big Leaf" approach

  19. Potential indicators of final ecosystem services in wetlands

    EPA Science Inventory

    Numerous and inconsistent lists of wetland ecosystem services exist because services are identified using ambiguous definitions or categorization schemes based around divergent or ambiguous objectives. A consistent and scientific approach would provide clarity and provide greater...

  20. Controls on Nitrogen Retention and Loss in Urban and Rural Forest Ecosystems.

    NASA Astrophysics Data System (ADS)

    Templer, P. H.

    2011-12-01

    Human activities, such as the burning of fossil fuels and production of fertilizer, have increased the amount of nitrogen deposited onto terrestrial ecosystems. In addition to changes in atmospheric deposition of nitrogen, other human-induced disturbances have led to dramatic shifts in forest composition of the United States over the last 100 years. Tree species composition of many forests is changing in response to introduced pests and pathogens, competition with introduced plant species and changes in climate. Understanding the combined effects of increased nitrogen inputs and changes in plant species composition on forest nitrogen cycling is critical to our understanding of forest biogeochemistry and nutrient budgets. Despite several decades of research on the effects of atmospheric nitrogen deposition, there is still significant uncertainty about the factors that regulate nitrogen retention and loss in forest ecosystems. The use of natural abundance stable isotopes of nitrogen and oxygen has proven to be a powerful tool for tracing the sources of nitrate in water, from inputs to leaching, as it moves through an ecosystem. The evaluation of natural abundance nitrogen values in atmospheric deposition has been used to partition sources of nitrogen, such as coal-fired power plants vs. tailpipe exhaust, since each of their isotopic signatures is distinct. Similarly, natural abundance oxygen values of nitrate in atmospheric inputs and soil leachate have been used as a tool to partition sources of nitrate between precipitation and nitrate produced microbially during nitrification. We measured the natural abundance isotopic composition of nitrate to quantify rates of nitrogen inputs to the forest and to determine rates of nitrogen losses from healthy, declining and preemptively cut eastern hemlock (Tsuga canadensis) stands in both an urban forest at the Arnold Arboretum in Boston, MA, and a rural forest at Harvard Forest in Petersham, MA. The hemlock woolly adelgid

  1. Forest ecosystem development in post-mining landscapes: a case study of the Lusatian lignite district.

    PubMed

    Hüttl, R F; Weber, E

    2001-08-01

    The restoration of surface mining landscapes requries the (re)creation of ecosystems. In Lusatia (eastern Germany), large-scale open-cast lignite mining operations generated spoil dumps widely consisting of acidified, phytotoxic substrates. Amelioration and rehabilitation measures have been developed and applied to these substrates since the 1950s. However, it is still not clear whether these approaches are sustainable. This paper reports on collaborative research work into the ecological potential of forest ecosystem development on typical minesites in the Lusatian lignite district. At first sight, pine stands on minesites along a chronosequence comprising about 35 years did not show differences when compared with stands on non-mined sites of the general region. Furthermore, with some modification, conceptual models for flora and fauna succession in forest stands on non-mined sites seem to be applicable, at least for the early stages of forest ecosystem development. For example, soil organism abundance and activity at minesites had already reached levels typical of non-mined sites after about 20-30 years. In contrast, mine soils are very different from non-mined soils of the test region. Chemically, mine soil development is dominated by processes originating from pyrite oxidation. Geogenic, i.e. lignitic, soil organic carbon was shown to substitute for some functions of pedogenic soil organic matter. Rooting was hampered but not completely impeded in strongly acidified soil compartments. Roots and mycorrhizae are apparently able to make use of the characteristic heterogeneity of young mine soils. Considering these recent results and the knowledge accumulated during more than 30 years of research on minesite rehabilitation internationally, it can be stated that minesite restoration might be used as an ideal case study for forest ecosystem development starting at "point zero" on "terra nova".

  2. Declining plant nitrogen supply and carbon accumulation in ageing primary boreal forest ecosystems

    NASA Astrophysics Data System (ADS)

    Högberg, Mona N.; Yarwood, Stephanie A.; Trumbore, Susan; Högberg, Peter

    2016-04-01

    Boreal forest soils are commonly characterized by a low plant nitrogen (N) supply. A high tree below-ground allocation of carbon (C) to roots and soil microorganisms in response to the shortage of N may lead to high microbial immobilisation of N, thus aggravating the N limitation. We studied the N supply at a Swedish boreal forest ecosystem chronosequence created by new land rising out of the sea due to iso-static rebound. The youngest soils develop with meadows by the coast, followed by a zone of dinitrogen fixing alder trees, and primary boreal conifer forest on ground up to 560 years old. With increasing ecosystem age, the proportion of microbial C out of the total soil C pool from the youngest to the oldest coniferous ecosystem was constant (c. 1-1.5%), whereas immobilised N (microbial N out of total soil N) increased and approached the levels commonly observed in similar boreal coniferous forests (c. 6-7 %), whereas gross N mineralization declined. Simultaneously, plant foliar N % decreased and the natural abundance of N-15 in the soil increased. More specifically, the difference in N-15 between plant foliage and soil increased, which is related to greater retention of N-15 relative to N-14 by ectomycorrhizal fungi as N is taken up from the soil and some N is transferred to the plant host. In the conifer forest, where these changes were greatest, we found increased fungal biomass in the F- and H-horizons of the mor-layer, in which ectomycorrhizal fungi are known to dominate (the uppermost horizon with litter and moss is dominated by saprotrophic fungi). Hence, we propose that the decreasing N supply to the plants and the subsequent decline in plant production in ageing boreal forests is linked to high tree belowground C allocation to C limited ectomycorrhizal fungi (and other soil microorganisms), a strong sink for available soil N. Data on organic matter C-14 suggested that the largest input of recently fixed plant C occurred in the younger coniferous forest

  3. Global topics and novel approaches in the study of air pollution, climate change and forest ecosystems.

    PubMed

    Sicard, Pierre; Augustaitis, Algirdas; Belyazid, Salim; Calfapietra, Carlo; de Marco, Alessandra; Fenn, Mark; Bytnerowicz, Andrzej; Grulke, Nancy; He, Shang; Matyssek, Rainer; Serengil, Yusuf; Wieser, Gerhard; Paoletti, Elena

    2016-06-01

    Research directions from the 27th conference for Specialists in Air Pollution and Climate Change Effects on Forest Ecosystems (2015) reflect knowledge advancements about (i) Mechanistic bases of tree responses to multiple climate and pollution stressors, in particular the interaction of ozone (O3) with nitrogen (N) deposition and drought; (ii) Linking genetic control with physiological whole-tree activity; (iii) Epigenetic responses to climate change and air pollution; (iv) Embedding individual tree performance into the multi-factorial stand-level interaction network; (v) Interactions of biogenic and anthropogenic volatile compounds (molecular, functional and ecological bases); (vi) Estimating the potential for carbon/pollution mitigation and cost effectiveness of urban and peri-urban forests; (vii) Selection of trees adapted to the urban environment; (viii) Trophic, competitive and host/parasite relationships under changing pollution and climate; (ix) Atmosphere-biosphere-pedosphere interactions as affected by anthropospheric changes; (x) Statistical analyses for epidemiological investigations; (xi) Use of monitoring for the validation of models; (xii) Holistic view for linking the climate, carbon, N and O3 modelling; (xiii) Inclusion of multiple environmental stresses (biotic and abiotic) in critical load determinations; (xiv) Ecological impacts of N deposition in the under-investigated areas; (xv) Empirical models for mechanistic effects at the local scale; (xvi) Broad-scale N and sulphur deposition input and their effects on forest ecosystem services; (xvii) Measurements of dry deposition of N; (xviii) Assessment of evapotranspiration; (xix) Remote sensing assessment of hydrological parameters; and (xx) Forest management for maximizing water provision and overall forest ecosystem services. Ground-level O3 is still the phytotoxic air pollutant of major concern to forest health. Specific issues about O3 are: (xxi) Developing dose-response relationships and

  4. Controls on 13C of ecosystem respired CO2 in Southeastern US forests

    NASA Astrophysics Data System (ADS)

    Mortazavi, B.; Chanton, J.; Smith, M.

    2006-12-01

    Pine-dominated southeastern United States forests constitute the largest documented carbon sink among North American or European forests. The extent of large-scale (hundreds of kilometers) spatial variability in the isotopic composition of ecosystem respired CO2 in this region is unresolved. We determined the δ13C of ecosystem (δCr), soil (δCs), and foliage (δCf) respired CO2 over a 2 year period (i) in a rotation-aged pine plantation and a (ii) 80 year old naturally regenerated pine forest in Florida, and contrasted our results with those from similar investigations in a pine plantation and naturally regenerated hardwood forest in North Carolina. We related δCr, δCf, and δCs to environmental factors using a time lag of 5 days. This time lag was based on metabolic pool turnover times determined with a year-long slash pine labeling experiment. Despite large variability in aboveground meteorological conditions, the isotopic composition of ecosystem respired carbon remained relatively constant. The isotopic composition of foliage soluble carbohydrates exhibited the same order of variability as δCr. Soil and stem water δ 18O profiles at both Florida sites indicate that the plants' primary water uptake zone is below the surficial layer of highly variable moisture content. This suggests that the plants are less responsive to variability in aboveground meteorological conditions due to reliable access to groundwater. In contrast, the forests studied in North Carolina derive water primarily from the variable surficial zone, and exhibited a time-lagged response to aboveground conditions. These results highlight that successful regional-scale generalizations of δCr based on local measurements must account for spatial variability in plant physiological responses to meteorological conditions and surface soil water conditions.

  5. MULTIVARIATE ANALYSIS OF DIATOM ASSEMBLAGES IN STREAMS IN TWO HYDROGEOMORPHIC REGIONS WITHIN THE NORTHERN LAKES AND FOREST ECOSYSTEM

    EPA Science Inventory

    An ordination approach was used to explore relationships among macroinvertebrate, habitat and landscape variables associated with diatom assemblages in streams within the Northern Lakes and Forest Ecosystem in two different hydrogeomorphic regions (i.e. the North Shore Highlands ...

  6. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    PubMed Central

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-01-01

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition. PMID:26059183

  7. [Energy flux and energy balance closure of intensively managed lei bamboo forest ecosystem].

    PubMed

    Chen, Yun-fei; Jiang, Hong; Zhou, Guo-mo; Sun, Cheng; Chen, Jian

    2013-04-01

    By using open-path eddy covariance system and meteorological instruments, an observation was conducted on the sensitive heat flux, latent heat flux, net radiation, soil heat flux, air temperature, ground temperature, and precipitation in a intensively managed Lei bamboo forest ecosystem in 2011, with the diurnal and monthly variations of energy flux as well as the distribution pattern of each energy component analyzed, and the Bowen ratio and energy balance closure calculated. The yearly net radiation of the forest ecosystem was 2928. 92 MJ m-2, and the latent heat flux, sensitive heat flux, and soil heat flux were 1384.90, 927.54, and -28.27 MJ m-2, respectively. Both the daily and the monthly variations of the energy components showed a single peak curve. The sensible and latent heat fluxes were 31.7% and 47.3% of the net radiation, respectively, indicating that latent heat flux was the main form of energy loss. The Bowen ratio followed the "U"-shaped pattern, and fluctuated from 0. 285 to 2. 062, suggesting that soil was a heat source. The yearly energy balance closure of the forest ecosystem was 0. 782, and the monthly average was 0.808. PMID:23898666

  8. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-06-01

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition.

  9. Direct quantification of long-term rock nitrogen inputs to temperate forest ecosystems.

    PubMed

    Morford, Scott L; Houlton, Benjamin Z; Dahlgren, Randy A

    2016-01-01

    Sedimentary and metasedimentary rocks contain large reservoirs of fixed nitrogen (N), but questions remain over the importance of rock N weathering inputs in terrestrial ecosystems. Here we provide direct evidence for rock N weathering (i.e., loss of N from rock) in three temperate forest sites residing on a N-rich parent material (820-1050 mg N kg(-1); mica schist) in the Klamath Mountains (northern California and southern Oregon), USA. Our method combines a mass balance model of element addition/ depletion with a procedure for quantifying fixed N in rock minerals, enabling quantification of rock N inputs to bioavailable reservoirs in soil and regolith. Across all sites, -37% to 48% of the initial bedrock N content has undergone long-term weathering in the soil. Combined with regional denudation estimates (sum of physical + chemical erosion), these weathering fractions translate to 1.6-10.7 kg x ha(-1) x yr(-1) of rock N input to these forest ecosystems. These N input fluxes are substantial in light of estimates for atmospheric sources in these sites (4.5-7.0 kg x ha(-1) x yr(-1)). In addition, N depletion from rock minerals was greater than sodium, suggesting active biologically mediated weathering of growth-limiting nutrients compared to nonessential elements. These results point to regional tectonics, biologically mediated weathering effects, and rock N chemistry in shaping the magnitude of rock N inputs to the forest ecosystems examined.

  10. [Energy flux and energy balance closure of intensively managed lei bamboo forest ecosystem].

    PubMed

    Chen, Yun-fei; Jiang, Hong; Zhou, Guo-mo; Sun, Cheng; Chen, Jian

    2013-04-01

    By using open-path eddy covariance system and meteorological instruments, an observation was conducted on the sensitive heat flux, latent heat flux, net radiation, soil heat flux, air temperature, ground temperature, and precipitation in a intensively managed Lei bamboo forest ecosystem in 2011, with the diurnal and monthly variations of energy flux as well as the distribution pattern of each energy component analyzed, and the Bowen ratio and energy balance closure calculated. The yearly net radiation of the forest ecosystem was 2928. 92 MJ m-2, and the latent heat flux, sensitive heat flux, and soil heat flux were 1384.90, 927.54, and -28.27 MJ m-2, respectively. Both the daily and the monthly variations of the energy components showed a single peak curve. The sensible and latent heat fluxes were 31.7% and 47.3% of the net radiation, respectively, indicating that latent heat flux was the main form of energy loss. The Bowen ratio followed the "U"-shaped pattern, and fluctuated from 0. 285 to 2. 062, suggesting that soil was a heat source. The yearly energy balance closure of the forest ecosystem was 0. 782, and the monthly average was 0.808.

  11. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    PubMed

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-06-10

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition.

  12. Direct quantification of long-term rock nitrogen inputs to temperate forest ecosystems.

    PubMed

    Morford, Scott L; Houlton, Benjamin Z; Dahlgren, Randy A

    2016-01-01

    Sedimentary and metasedimentary rocks contain large reservoirs of fixed nitrogen (N), but questions remain over the importance of rock N weathering inputs in terrestrial ecosystems. Here we provide direct evidence for rock N weathering (i.e., loss of N from rock) in three temperate forest sites residing on a N-rich parent material (820-1050 mg N kg(-1); mica schist) in the Klamath Mountains (northern California and southern Oregon), USA. Our method combines a mass balance model of element addition/ depletion with a procedure for quantifying fixed N in rock minerals, enabling quantification of rock N inputs to bioavailable reservoirs in soil and regolith. Across all sites, -37% to 48% of the initial bedrock N content has undergone long-term weathering in the soil. Combined with regional denudation estimates (sum of physical + chemical erosion), these weathering fractions translate to 1.6-10.7 kg x ha(-1) x yr(-1) of rock N input to these forest ecosystems. These N input fluxes are substantial in light of estimates for atmospheric sources in these sites (4.5-7.0 kg x ha(-1) x yr(-1)). In addition, N depletion from rock minerals was greater than sodium, suggesting active biologically mediated weathering of growth-limiting nutrients compared to nonessential elements. These results point to regional tectonics, biologically mediated weathering effects, and rock N chemistry in shaping the magnitude of rock N inputs to the forest ecosystems examined. PMID:27008775

  13. Possibilities of a Personal Laser Scanning System for Forest Mapping and Ecosystem Services

    PubMed Central

    Liang, Xinlian; Kukko, Antero; Kaartinen, Harri; Hyyppä, Juha; Yu, Xiaowei; Jaakkola, Anttoni; Wang, Yunsheng

    2014-01-01

    A professional-quality, personal laser scanning (PLS) system for collecting tree attributes was demonstrated in this paper. The applied system, which is wearable by human operators, consists of a multi-constellation navigation system and an ultra-high-speed phase-shift laser scanner mounted on a rigid baseplate and consisting of a single sensor block. A multipass-corridor-mapping method was developed to process PLS data and a 2,000 m2 forest plot was utilized in the test. The tree stem detection accuracy was 82.6%; the root mean square error (RMSE) of the estimates of tree diameter at breast height (DBH) was 5.06 cm; the RMSE of the estimates of tree location was 0.38 m. The relative RMSE of the DBH estimates was 14.63%. The results showed, for the first time, the potential of the PLS system in mapping large forest plots. Further research on mapping accuracy in various forest conditions, data correction methods and multi-sensoral positioning techniques is needed. The utilization of this system in different applications, such as harvester operations, should also be explored. In addition to collecting tree-level and plot-level data for forest inventory, other possible applications of PLS for forest ecosystem services include mapping of canopy gaps, measuring leaf area index of large areas, documenting and visualizing forest routes feasible for recreation, hiking and berry and mushroom picking. PMID:24434879

  14. Influence of forest management systems on natural resource use and provision of ecosystem services in Tanzania.

    PubMed

    Strauch, Ayron M; Rurai, Masegeri T; Almedom, Astier M

    2016-09-15

    Social, religious and economic facets of rural livelihoods in Sub-Saharan Africa are heavily dependent on natural resources, but improper resource management, drought, and social instability frequently lead to their unsustainable exploitation. In rural Tanzania, natural resources are often governed locally by informal systems of traditional resource management (TRM), defined as cultural practices developed within the context of social and religious institutions over hundreds of years. However, following independence from colonial rule, centralized governments began to exercise jurisdictional control over natural resources. Following decades of mismanagement that resulted in lost ecosystem services, communities demanded change. To improve resource protection and participation in management among stakeholders, the Tanzanian government began to decentralize management programs in the early 2000s. We investigated these two differing management approaches (traditional and decentralized government) in Sonjo communities, to examine local perceptions of resource governance, management influences on forest use, and their consequences for forest and water resources. While 97% of households understood the regulations governing traditionally-managed forests, this was true for only 39% of households for government-managed forests, leading to differences in forest use. Traditional management practices resulted in improved forest condition and surface water quality. This research provides an essential case study demonstrating the importance of TRM in shaping decision frameworks for natural resource planning and management.

  15. Carbon fluxes in tropical forest ecosystems: the value of Eddy-covariance data for individual-based dynamic forest gap models

    NASA Astrophysics Data System (ADS)

    Roedig, Edna; Cuntz, Matthias; Huth, Andreas

    2015-04-01

    The effects of climatic inter-annual fluctuations and human activities on the global carbon cycle are uncertain and currently a major issue in global vegetation models. Individual-based forest gap models, on the other hand, model vegetation structure and dynamics on a small spatial (<100 ha) and large temporal scale (>1000 years). They are well-established tools to reproduce successions of highly-diverse forest ecosystems and investigate disturbances as logging or fire events. However, the parameterizations of the relationships between short-term climate variability and forest model processes are often uncertain in these models (e.g. daily variable temperature and gross primary production (GPP)) and cannot be constrained from forest inventories. We addressed this uncertainty and linked high-resolution Eddy-covariance (EC) data with an individual-based forest gap model. The forest model FORMIND was applied to three diverse tropical forest sites in the Amazonian rainforest. Species diversity was categorized into three plant functional types. The parametrizations for the steady-state of biomass and forest structure were calibrated and validated with different forest inventories. The parameterizations of relationships between short-term climate variability and forest model processes were evaluated with EC-data on a daily time step. The validations of the steady-state showed that the forest model could reproduce biomass and forest structures from forest inventories. The daily estimations of carbon fluxes showed that the forest model reproduces GPP as observed by the EC-method. Daily fluctuations of GPP were clearly reflected as a response to daily climate variability. Ecosystem respiration remains a challenge on a daily time step due to a simplified soil respiration approach. In the long-term, however, the dynamic forest model is expected to estimate carbon budgets for highly-diverse tropical forests where EC-measurements are rare.

  16. Disturbance Distance: Combining a process based ecosystem model and remote sensing data to map the vulnerability of U.S. forested ecosystems to potentially altered disturbance rates

    NASA Astrophysics Data System (ADS)

    Dolan, K. A.

    2015-12-01

    Disturbance plays a critical role in shaping the structure and function of forested ecosystems as well as the ecosystem services they provide, including but not limited to: carbon storage, biodiversity habitat, water quality and flow, and land atmosphere exchanges of energy and water. In addition, recent studies suggest that disturbance rates may increase in the future under altered climate and land use scenarios. Thus understanding how vulnerable forested ecosystems are to potential changes in disturbance rates is of high importance. This study calculated the theoretical threshold rate of disturbance for which forest ecosystems could no longer be sustained (λ*) across the Coterminous U.S. using an advanced process based ecosystem model (ED). Published rates of disturbance (λ) in 50 study sites were obtained from the North American Forest Disturbance (NAFD) program. Disturbance distance (λ* - λ) was calculated for each site by differencing the model based threshold under current climate conditions and average observed rates of disturbance over the last quarter century. Preliminary results confirm all sample forest sites have current average rates of disturbance below λ*, but there were interesting patterns in the recorded disturbance distances. In general western sites had much smaller disturbance distances, suggesting higher vulnerability to change, while eastern sites showed larger buffers. Ongoing work is being conducted to assess the vulnerability of these sites in the context of potential future changes by propagating scenarios of future climate and land-use change through the analysis.

  17. Drought Influence on a Missouri Oak-Hickory Forest Ecosystem

    NASA Astrophysics Data System (ADS)

    Yang, B.; Pallardy, S. G.; Meyers, T. P.; Gu, L.; Hanson, P. J.; Wullschleger, S. D.; Heuer, M.; Hosman, K. P.; Riggs, J. S.

    2005-12-01

    A severe drought was observed in the mid-summer 2005 at the Missouri MOFLUX oak-hickory forest site. It largely covered the entire month of July and the early August. The monthly mean temperature in July measured at the site was 26.2 °C, 1 °C higher than the climatic mean between 1970 and 2000 and almost 3 °C higher than 2004. The cumulative precipitation in July was only about 19 mm, 77 mm less than the climatic mean (1971-2000) and 118 mm less than 2004. Mean daytime vapor pressure deficit measured at each 30-minute period was 1.97 KPa in July 2005, about 0.44 KPa higher than July 2004, and its daily peak often exceeded 2.5 to 3.0 KPa during the drought. At the site, fluxes of CO2, latent heat and sensible heat are routinely measured by an eddy covariance system above the canopy. As volumetric soil water content between 0.6 and 1.2 m declined from 0.4 at the beginning of the drought to 0.32 at the end of drought, daily maximum CO2 uptake dropped from 30 μmol m-2 s-1 to less than 10 μmol m-2 s-1. Concurrently, daily maximum latent heat flux dropped from 500 W m-2 or more to 200 W m-2 or less and daily maximum sensible heat flux rose up from about 200 W m-2 to 500 W m-2. Mean predawn leaf water potential of trees decreased from -0.3 MPa just prior to the drought to -2.5 MPa at peak drought. Soil respiration measured by 8 automated chambers also decreased dramatically, and the 30-minute mean was reduced from more than 5 μmol m-2 s-1 to about 2 μmol m-2 s-1. As a result of stomatal closure in the afternoon under water stress and high vapor pressure deficit, the daily peak of CO2 uptake was shifted from noontime to the morning hours. Light saturation occurred at about 500 μmol m-2 s-1 in the drought season, which was only half of that in the pre-drought period of 2005 and in the growing season 2004. It is clear that water stress was the primary driving force for the drought. However, we also found evidence indicating that high vapor pressure deficit added to

  18. Simulating the impacts of land use in northwest Europe on Net Ecosystem Exchange (NEE): the role of arable ecosystems, grasslands and forest plantations in climate change mitigation.

    PubMed

    Abdalla, Mohamed; Saunders, Matthew; Hastings, Astley; Williams, Mike; Smith, Pete; Osborne, Bruce; Lanigan, Gary; Jones, Mike B

    2013-11-01

    In this study, we compared measured and simulated Net Ecosystem Exchange (NEE) values from three wide spread ecosystems in the southeast of Ireland (forest, arable and grassland), and investigated the suitability of the DNDC (the DeNitrification-DeComposition) model to estimate present and future NEE. Although, the field-DNDC version overestimated NEE at temperatures >5 °C, forest-DNDC under-estimated NEE at temperatures >5 °C. The results suggest that the field/forest DNDC models can successfully estimate changes in seasonal and annual NEE from these ecosystems. Differences in NEE were found to be primarily land cover specific. The annual NEE was similar for the grassland and arable sites, but due to the contribution of exported carbon, the soil carbon increased at the grassland site and decreased at the arable site. The NEE of the forest site was an order of magnitude larger than that of the grassland or arable ecosystems, with large amounts of carbon stored in woody biomass and the soil. The average annual NEE, GPP and Reco values over the measurement period were -904, 2379 and 1475 g C m(-2) (forest plantations), -189, 906 and 715 g C m(-2) (arable systems) and -212, 1653 and 1444 g C m(-2) (grasslands), respectively. The average RMSE values were 3.8 g C m(-2) (forest plantations), 0.12 g C m(-2) (arable systems) and 0.21 g C m(-2) (grasslands). When these models were run with climate change scenarios to 2060, predictions show that all three ecosystems will continue to operate as carbon sinks. Further, climate change may decrease the carbon sink strength in the forest plantations by up to 50%. This study supports the use of the DNDC model as a valid tool to predict the consequences of climate change on NEE from different ecosystems.

  19. Simulating the impacts of land use in northwest Europe on Net Ecosystem Exchange (NEE): the role of arable ecosystems, grasslands and forest plantations in climate change mitigation.

    PubMed

    Abdalla, Mohamed; Saunders, Matthew; Hastings, Astley; Williams, Mike; Smith, Pete; Osborne, Bruce; Lanigan, Gary; Jones, Mike B

    2013-11-01

    In this study, we compared measured and simulated Net Ecosystem Exchange (NEE) values from three wide spread ecosystems in the southeast of Ireland (forest, arable and grassland), and investigated the suitability of the DNDC (the DeNitrification-DeComposition) model to estimate present and future NEE. Although, the field-DNDC version overestimated NEE at temperatures >5 °C, forest-DNDC under-estimated NEE at temperatures >5 °C. The results suggest that the field/forest DNDC models can successfully estimate changes in seasonal and annual NEE from these ecosystems. Differences in NEE were found to be primarily land cover specific. The annual NEE was similar for the grassland and arable sites, but due to the contribution of exported carbon, the soil carbon increased at the grassland site and decreased at the arable site. The NEE of the forest site was an order of magnitude larger than that of the grassland or arable ecosystems, with large amounts of carbon stored in woody biomass and the soil. The average annual NEE, GPP and Reco values over the measurement period were -904, 2379 and 1475 g C m(-2) (forest plantations), -189, 906 and 715 g C m(-2) (arable systems) and -212, 1653 and 1444 g C m(-2) (grasslands), respectively. The average RMSE values were 3.8 g C m(-2) (forest plantations), 0.12 g C m(-2) (arable systems) and 0.21 g C m(-2) (grasslands). When these models were run with climate change scenarios to 2060, predictions show that all three ecosystems will continue to operate as carbon sinks. Further, climate change may decrease the carbon sink strength in the forest plantations by up to 50%. This study supports the use of the DNDC model as a valid tool to predict the consequences of climate change on NEE from different ecosystems. PMID:23384575

  20. Protection of nature and the ecological equilibrium--on the forest ecosystem of Xishuangbanna and the Yunnan plateau

    SciTech Connect

    Wang Yequ

    1983-08-01

    This article discusses the protection of the natural resources and the ecological equilibrium of tropical monsoon forests in China. During the past 10 years, more than 7 million mu of the Xishuangbanna Zhou forest has been destroyed, causing destruction of the tropical monsoon rain forest ecosystem and bringing about a decline or near extinction of rare and valuable fauna and flora. A deterioration of climatic and hydrological conditions and serious erosion have also resulted. Topics considered include the characteristics of the plateau, the relationship between the tropical monsoon forest ecosystem and the growing of rubber, and the relationship between the forest ecosystem and population ecology. It is recommended that the areas most suited to the growing of rubber must be designated, the farms should be consolidated, and an economic contract system should be instituted with the proportion of all-around farming, forestry, and rubber growing operations increased.

  1. Evidence and implications of recent and projected climate change in Alaska's forest ecosystems

    USGS Publications Warehouse

    Wolken, Jane M.; Hollingsworth, Teresa N.; Rupp, T. Scott; Chapin, Stuart III; Trainor, Sarah F.; Barrett, Tara M.; Sullivan, Patrick F.; McGuire, A. David; Euskirchen, Eugénie S.; Hennon, Paul E.; Beever, Erik A.; Conn, Jeff S.; Crone, Lisa K.; D'Amore, David V.; Fresco, Nancy; Hanley, Thomas A.; Kielland, Knut; Kruse, James J.; Patterson, Trista; Schuur, Edward A.G.; Verbyla, David L.; Yarie, John

    2011-01-01

    The structure and function of Alaska's forests have changed significantly in response to a changing climate, including alterations in species composition and climate feedbacks (e.g., carbon, radiation budgets) that have important regional societal consequences and human feedbacks to forest ecosystems. In this paper we present the first comprehensive synthesis of climate-change impacts on all forested ecosystems of Alaska, highlighting changes in the most critical biophysical factors of each region. We developed a conceptual framework describing climate drivers, biophysical factors and types of change to illustrate how the biophysical and social subsystems of Alaskan forests interact and respond directly and indirectly to a changing climate. We then identify the regional and global implications to the climate system and associated socio-economic impacts, as presented in the current literature. Projections of temperature and precipitation suggest wildfire will continue to be the dominant biophysical factor in the Interior-boreal forest, leading to shifts from conifer- to deciduous-dominated forests. Based on existing research, projected increases in temperature in the Southcentral- and Kenai-boreal forests will likely increase the frequency and severity of insect outbreaks and associated wildfires, and increase the probability of establishment by invasive plant species. In the Coastal-temperate forest region snow and ice is regarded as the dominant biophysical factor. With continued warming, hydrologic changes related to more rapidly melting glaciers and rising elevation of the winter snowline will alter discharge in many rivers, which will have important consequences for terrestrial and marine ecosystem productivity. These climate-related changes will affect plant species distribution and wildlife habitat, which have regional societal consequences, and trace-gas emissions and radiation budgets, which are globally important. Our conceptual framework facilitates

  2. Long-term changes in soil pH across major forest ecosystems in China

    NASA Astrophysics Data System (ADS)

    Yang, Yuanhe; Li, Pin; He, Honglin; Zhao, Xia; Datta, Arindam; Ma, Wenhong; Zhang, Ying; Liu, Xuejun; Han, Wenxuan; Wilson, Maxwell C.; Fang, Jingyun

    2015-02-01

    Atmospheric acidic deposition has been a major environmental problem since the industrial revolution. However, our understanding of the effect of acidic deposition on soil pH is inconclusive. Here we examined temporal variations in topsoil pH and their relationships with atmospheric sulfur and nitrogen deposition across China's forests from the 1980s to the 2000s. To accomplish this goal, we conducted artificial neural network simulations using historical soil inventory data from the 1980s and a data set synthesized from literature published after 2000. Our results indicated that significant decreases in soil pH occurred in broadleaved forests, while minor changes were observed in coniferous and mixed coniferous and broadleaved forests. The magnitude of soil pH change was negatively correlated with atmospheric sulfur and nitrogen deposition. This relationship highlights the need for stringent measures that reduce sulfur and nitrogen emissions so as to maintain ecosystem structure and function.

  3. An ecosystem-scale model for the spread of a host-specific forest pathogen in the Greater Yellowstone Ecosystem

    USGS Publications Warehouse

    Hatala, J.A.; Dietze, M.C.; Crabtree, R.L.; Kendall, K.; Six, D.; Moorcroft, P.R.

    2011-01-01

    The introduction of nonnative pathogens is altering the scale, magnitude, and persistence of forest disturbance regimes in the western United States. In the high-altitude whitebark pine (Pinus albicaulis) forests of the Greater Yellowstone Ecosystem (GYE), white pine blister rust (Cronartium ribicola) is an introduced fungal pathogen that is now the principal cause of tree mortality in many locations. Although blister rust eradication has failed in the past, there is nonetheless substantial interest in monitoring the disease and its rate of progression in order to predict the future impact of forest disturbances within this critical ecosystem. This study integrates data from five different field-monitoring campaigns from 1968 to 2008 to create a blister rust infection model for sites located throughout the GYE. Our model parameterizes the past rates of blister rust spread in order to project its future impact on highaltitude whitebark pine forests. Because the process of blister rust infection and mortality of individuals occurs over the time frame of many years, the model in this paper operates on a yearly time step and defines a series of whitebark pine infection classes: susceptible, slightly infected, moderately infected, and dead. In our analysis, we evaluate four different infection models that compare local vs. global density dependence on the dynamics of blister rust infection. We compare models in which blister rust infection is: (1) independent of the density of infected trees, (2) locally density-dependent, (3) locally density-dependent with a static global infection rate among all sites, and (4) both locally and globally density-dependent. Model evaluation through the predictive loss criterion for Bayesian analysis supports the model that is both locally and globally density-dependent. Using this best-fit model, we predicted the average residence times for the four stages of blister rust infection in our model, and we found that, on average, whitebark

  4. The role of stoichiometric flexibility in modelling forest ecosystem responses to nitrogen fertilization.

    PubMed

    Meyerholt, Johannes; Zaehle, Sönke

    2015-12-01

    The response of the forest carbon (C) balance to changes in nitrogen (N) deposition is uncertain, partly owing to diverging representations of N cycle processes in dynamic global vegetation models (DGVMs). Here, we examined how different assumptions about the degree of flexibility of the ecosystem's C : N ratios contribute to this uncertainty, and which of these assumptions best correspond to the available data. We applied these assumptions within the framework of a DGVM and compared the results to responses in net primary productivity (NPP), leaf N concentration, and ecosystem N partitioning, observed at 22 forest N fertilization experiments. Employing flexible ecosystem pool C : N ratios generally resulted in the most convincing model-data agreement with respect to production and foliar N responses. An intermediate degree of stoichiometric flexibility in vegetation, where wood C : N ratio changes were decoupled from leaf and root C : N ratio changes, led to consistent simulation of production and N cycle responses to N addition. Assuming fixed C : N ratios or scaling leaf N concentration changes to other tissues, commonly assumed by DGVMs, was not supported by reported data. Between the tested assumptions, the simulated changes in ecosystem C storage relative to changes in C assimilation varied by up to 20%.

  5. Pervasive Drought Legacy Effects in Forest Ecosystems and their Carbon Cycle Implications

    NASA Astrophysics Data System (ADS)

    Anderegg, W.; Schwalm, C.; Biondi, F.; Camarero, J. J.; Koch, G. W.; Litvak, M. E.; Ogle, K.; Shaw, J.; Shevliakova, E.; Williams, P.; Wolf, A.; Ziaco, E.; Pacala, S. W.

    2015-12-01

    The impacts of climate extremes on terrestrial ecosystems are poorly understood but central for predicting carbon cycle feedbacks to climate change. Coupled climate-carbon cycle models typically assume that vegetation recovery from extreme drought is immediate and complete, which conflicts with basic plant physiological understanding. We examine the recovery of tree stem growth after severe drought at 1,338 forest sites globally comprising 49,339 site-years and compare it to simulated recovery in climate-vegetation models. We find pervasive and substantial "legacy effects" of reduced growth and incomplete recovery for 1-4 years after severe drought, and that legacy effects are most prevalent in dry ecosystems, Pinaceae, and species with low hydraulic safety margins. In contrast, no or limited legacy effects are simulated in current climate-vegetation models after drought. Our results highlight hysteresis in ecosystem carbon cycling and delayed recovery from climate extremes.

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

    PubMed Central

    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

  7. Interacting factors driving a major loss of large trees with cavities in a forest ecosystem.

    PubMed

    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.

  8. The relationship between hurricane wind fields and the associated disturbance in US forest ecosystems

    NASA Astrophysics Data System (ADS)

    Negron Juarez, R. I.; Chambers, J. Q.; Hurtt, G. C.; Fisk, J. P.

    2011-12-01

    Tropical cyclones are recurrent in the U. S. Gulf Coast and produce drastic disturbance to the forest ecosystem by altering forest structure, species composition, nutrient cycling, biomass accumulation, etc. The recurrent characteristics of these events demand a rapid yet reliable assessment of forest disturbance in order to provide better management decisions, as well as to evaluate damage to the landscape, biomass loss and the associated impacts to the regional carbon budget. In this study we present a methodology for rapid assessment of forest disturbance produced by tropical cyclones based on maximum sustained wind swaths (H*wind), MODIS (Moderate Resolution Imaging Spectroradiometer)-derived disturbances and field-measured tree mortality collected in Gulf Coast forests. MODIS images in May (the month of maximum greenness) before the disturbance and in May of the year following the disturbance were processed using spectral mixture analysis (SMA) using image derived end-members. The changes in non-photosynthetic vegetation (ΔNPV, related to wood, dead vegetation and surface litter) from one year to the next was used as the disturbance metric. A strong correlation was found between H*wind and MODIS ΔNPV for hurricanes Charley (2004), Katrina (2005), Rita (2005), and Gustav (2008). In turn, MODIS ΔNPV was shown to have a strong correlation with field-measured mortality. The forest disturbance estimates based on hurricane wind-field and MODIS ΔNPV agree with those published in our previous studies. This study establishes an important relationship that could be incorporated into earth system models to improve our understanding of the effect of tropical cyclones on terrestrial ecosystems and their associated feedbacks within the climate system.

  9. Vegetation composition, dynamics, and management of a bracken-grassland and northern-dry forest ecosystem.

    PubMed

    Nielsen, Scott E; Haney, Alan

    2003-06-01

    We investigated differences in vegetation composition and dynamics for two globally rare ecosystems, bracken-grasslands and northern-dry forests of northern Wisconsin. These ecosystems commonly have been viewed as degraded pine barrens. Bracken-grasslands contained a high dominance of exotic species, low native richness, and no obvious prairie species, suggesting logging-era anthropogenic origins. Differences in cover for common plants among ecosystems were examined using Mann-Whitney U tests of equivalence. Cover of all 8 graminoid species, 4 of 5 Ericaceae and Myricaceae species, and 10 of 17 species of forbs were significantly different between ecosystems. Vegetation changes over a 4-year period were examined through detrended correspondence analysis (DCA) and analysis of variance (ANOVA) repeated measures. DCA analyses of community composition failed to detect significant temporal trends within individual management units, although differences were apparent between ecosystems, regardless of sample year. In addition, no apparent patterns could be detected between years when comparing dominant individual species to management history (prescribed fire). This is contrary to what would be expected for a degraded pine barrens and questions the efficacy of using repeated prescribed fire as a management tool in bracken-grasslands. Methods for conservation and restoration of xeric ecosystems of northern Wisconsin have historically relied heavily on single species (e.g., sharp-tailed grouse) wildlife models, without full consideration of other factors. We suggest that stakeholders involved in these restoration projects examine historic processes and reference conditions prior to formulating management goals. Greater attention to the differentiation and individual management needs of pine barrens, northern-dry forests, and bracken-grasslands is needed. PMID:14565700

  10. Vulnerability to climate-induced changes in ecosystem services of boreal forests

    NASA Astrophysics Data System (ADS)

    Holmberg, Maria; Rankinen, Katri; Aalto, Tuula; Akujärvi, Anu; Nadir Arslan, Ali; Liski, Jari; Markkanen, Tiina; Mäkelä, Annikki; Peltoniemi, Mikko

    2016-04-01

    Boreal forests provide an array of ecosystem services. They regulate climate, and carbon, water and nutrient fluxes, and provide renewable raw material, food, and recreational possibilities. Rapid climate warming is projected for the boreal zone, and has already been observed in Finland, which sets these services at risk. MONIMET (LIFE12 ENV/FI/000409, 2.9.2013 - 1.9.2017) is a project funded by EU Life programme about Climate Change Indicators and Vulnerability of Boreal Zone Applying Innovative Observation and Modeling Techniques. The coordinating beneficiary of the project is the Finnish Meteorological Institute. Associated beneficiaries are the Natural Resources Institute Finland, the Finnish Environment Institute and the University of Helsinki. In the MONIMET project, we use state-of-the-art models and new monitoring methods to investigate the impacts of a warming climate on the provision of ecosystem services of boreal forests. This poster presents results on carbon storage in soil and assessment of drought indices, as a preparation for assessing the vulnerability of society to climate-induced changes in ecosystem services. The risk of decreasing provision of ecosystem services depends on the sensitivity of the ecosystem as well as its exposure to climate stress. The vulnerability of society, in turn, depends on the risk of decreasing provision of a certain service in combination with society's demand for that service. In the next phase, we will look for solutions to challenges relating to the quantification of the demand for ecosystem services and differences in spatial extent and resolution of the information on future supply and demand.

  11. Vegetation composition, dynamics, and management of a bracken-grassland and northern-dry forest ecosystem.

    PubMed

    Nielsen, Scott E; Haney, Alan

    2003-06-01

    We investigated differences in vegetation composition and dynamics for two globally rare ecosystems, bracken-grasslands and northern-dry forests of northern Wisconsin. These ecosystems commonly have been viewed as degraded pine barrens. Bracken-grasslands contained a high dominance of exotic species, low native richness, and no obvious prairie species, suggesting logging-era anthropogenic origins. Differences in cover for common plants among ecosystems were examined using Mann-Whitney U tests of equivalence. Cover of all 8 graminoid species, 4 of 5 Ericaceae and Myricaceae species, and 10 of 17 species of forbs were significantly different between ecosystems. Vegetation changes over a 4-year period were examined through detrended correspondence analysis (DCA) and analysis of variance (ANOVA) repeated measures. DCA analyses of community composition failed to detect significant temporal trends within individual management units, although differences were apparent between ecosystems, regardless of sample year. In addition, no apparent patterns could be detected between years when comparing dominant individual species to management history (prescribed fire). This is contrary to what would be expected for a degraded pine barrens and questions the efficacy of using repeated prescribed fire as a management tool in bracken-grasslands. Methods for conservation and restoration of xeric ecosystems of northern Wisconsin have historically relied heavily on single species (e.g., sharp-tailed grouse) wildlife models, without full consideration of other factors. We suggest that stakeholders involved in these restoration projects examine historic processes and reference conditions prior to formulating management goals. Greater attention to the differentiation and individual management needs of pine barrens, northern-dry forests, and bracken-grasslands is needed.

  12. Use of AIRS, OMI, MLS, and TES Data in Assessing Forest Ecosystem Exposure to Ozone

    NASA Technical Reports Server (NTRS)

    Spruce, Joseph P.

    2007-01-01

    Ground-level ozone at high levels poses health threats to exposed flora and fauna, including negative impacts to human health. While concern is common regarding depletion of ozone in the stratosphere, portions of the urban and rural United States periodically have high ambient levels of tropospheric ozone on the ground. Ozone pollution can cause a variety of impacts to susceptible vegetation (e.g., Ponderosa and Jeffrey pine species in the southwestern United States), such as stunted growth, alteration of growth form, needle or leaf chlorosis, and impaired ability to withstand drought-induced water stress. In addition, Southern Californian forests with high ozone exposures have been recently subject to multiyear droughts that have led to extensive forest overstory mortality from insect outbreaks and increased incidence of wildfires. Residual forests in these impacted areas may be more vulnerable to high ozone exposures and to other forest threats than ever before. NASA sensors collect a wealth of atmospheric data that have been used recently for mapping and monitoring regional tropospheric ozone levels. AIRS (Atmospheric Infrared Sounder), OMI (Ozone Monitoring Instrument), MLS (Microwave Limb Sounder), and TES (Tropospheric Emission Spectrometer) data could be used to assess forest ecosystem exposure to ozone. Such NASA data hold promise for providing better or at least complementary synoptic information on ground-level ozone levels that Federal agency partners can use to assess forest health trends and to mitigate the threats as needed in compliance with Federal laws and mandates. NASA data products on ozone concentrations may be able to aid applications of DSTs (decision support tools) adopted by the USDA FS (U.S. Department of Agriculture Forest Service) and by the NPS (National Park Service), such as the Ozone Calculator, in which ground ozone estimates are employed to assess ozone impacts to forested vegetation.

  13. Environmental Controls of Ecosystem Evapotranspiration (ET): Why generalized ET models do not work for forests?

    NASA Astrophysics Data System (ADS)

    Sun, G.; Fang, Y.; Caldwell, P.; Noormets, A.; domec, J.; McNulty, S.; King, J. S.; McLaughlin, S.; Uddling, J.; Chen, J.

    2012-12-01

    Forests return large amount of fresh water back to the atmosphere through the evapotranspiration (ET) processes, and thus forests have enormous influences on global water, energy, and bigeochemical cycles. Accurately quantifying forest evapotranspiration (ET) is essential to understanding ecohydrological processes, developing regional-scale water and carbon balances, and projecting impacts of environmental changes on natural resources. However, measuring and modeling forest ET remain challenging. Traditional ET models are designed for reference crops (e.g. short green grasses) and not for forested conditions with much higher above and below ground biomass. The large spatial and temporal variability of forests, and complex interactions between physical (temperature and precipitation) and chemical (CO2, Ozone) climate and tree ecophysiological responses also contribute to ET measurement complexity. In this study, we examined environmental controls on ecosystem level ET including forests using multiple measurements (sapflow, watershed hydrologic records, eddy flux measurements, and controlled experiments) and statistical techniques (multivariate linear regressions, best subset regression, stepwise regression). In general, eddy flux data suggest that temperature-based potential ET (PET), measured precipitation (P), and remotely sensed Leaf Area Index (LAI) - a key parameter of ecosystem structure - explain most of the variability of observed monthly forest ET (R2=0.67-0.95) across a wide range of climatic and ecosystem types. VPD is a major driver of forest ET, but P is a rather weak predictor for forest ET. Solar radiation and LAI were highly correlated with ET in grasslands, croplands, and shrublands. Ozone effect was detected only in the mature forests in the Eastern USA where the O3 levels can reach relatively high values. The O3 effect varied with climatic conditions, but the increase in tree transpiration was always associated with reduced streamflow. As the

  14. Does Acacia dealbata express shade tolerance in Mediterranean forest ecosystems of South America?

    PubMed Central

    Aguilera, Narciso; Sanhueza, Carolina; Guedes, Lubia M; Becerra, José; Carrasco, Sebastián; Hernández, Víctor

    2015-01-01

    The distribution of Acacia dealbata Link (Fabaceae) in its non-native range is associated with disturbed areas. However, the possibility that it can penetrate the native forest during the invasion process cannot be ruled out. This statement is supported by the fact that this species has been experimentally established successfully under the canopy of native forest. Nonetheless, it is unknown whether A. dealbata can express shade tolerance traits to help increase its invasive potential. We investigated the shade tolerance of A. dealbata under the canopy of two native forests and one non-native for three consecutive years, as well as its early growth and photosynthetic performance at low light intensities (9, 30, and 70 μmol m−2sec−1) under controlled conditions. We found many A. dealbata plants surviving and growing under the canopy of native and non-native forests. The number of plants of this invasive species remained almost constant under the canopy of native forests during the years of study. However, the largest number of A. dealbata plants was found under the canopy of non-native forest. In every case, the distribution pattern varied with a highest density of plants in forest edges decreasing progressively toward the inside. Germination and early growth of A. dealbata were slow but successful at three low light intensities tested under controlled conditions. For all tested light regimes, we observed that in this species, most of the energy was dissipated by photochemical processes, in accordance with the high photosynthetic rates that this plant showed, despite the really low light intensities under which it was grown. Our study reveals that A. dealbata expressed shade tolerance traits under the canopy of native and non-native forests. This behavior is supported by the efficient photosynthetic performance that A. dealbata showed at low light intensities. Therefore, these results suggest that Mediterranean forest ecosystems of South America can become

  15. Does Acacia dealbata express shade tolerance in Mediterranean forest ecosystems of South America?

    PubMed

    Aguilera, Narciso; Sanhueza, Carolina; Guedes, Lubia M; Becerra, José; Carrasco, Sebastián; Hernández, Víctor

    2015-08-01

    The distribution of Acacia dealbata Link (Fabaceae) in its non-native range is associated with disturbed areas. However, the possibility that it can penetrate the native forest during the invasion process cannot be ruled out. This statement is supported by the fact that this species has been experimentally established successfully under the canopy of native forest. Nonetheless, it is unknown whether A. dealbata can express shade tolerance traits to help increase its invasive potential. We investigated the shade tolerance of A. dealbata under the canopy of two native forests and one non-native for three consecutive years, as well as its early growth and photosynthetic performance at low light intensities (9, 30, and 70 μmol m(-2)sec(-1)) under controlled conditions. We found many A. dealbata plants surviving and growing under the canopy of native and non-native forests. The number of plants of this invasive species remained almost constant under the canopy of native forests during the years of study. However, the largest number of A. dealbata plants was found under the canopy of non-native forest. In every case, the distribution pattern varied with a highest density of plants in forest edges decreasing progressively toward the inside. Germination and early growth of A. dealbata were slow but successful at three low light intensities tested under controlled conditions. For all tested light regimes, we observed that in this species, most of the energy was dissipated by photochemical processes, in accordance with the high photosynthetic rates that this plant showed, despite the really low light intensities under which it was grown. Our study reveals that A. dealbata expressed shade tolerance traits under the canopy of native and non-native forests. This behavior is supported by the efficient photosynthetic performance that A. dealbata showed at low light intensities. Therefore, these results suggest that Mediterranean forest ecosystems of South America can become

  16. [Eco-value level classification and ecosystem management strategy of broad-leaved Korean pine forest in Changbai Mountain].

    PubMed

    Zheng, Jingming; Jiang, Fengqi; Zeng, Dehui

    2003-06-01

    To realize the sustainable management of forest ecosystems, we should explicitly clarify the types and differences of the ecosystem services provided by different ecosystems under different conditions, with rethinking about the value of forest ecosystems; then solid management strategies and measurements will be enacted and applied to achieve the objects. The broad-leaved Korean pine forest (BLKPF) in Changbai Mountain is a unique and important forest type in China, owing to its many important ecosystem services such as preventing soil erosion, regulating climates, nutrient cycling, providing wood and non-timber forest products, etc. This paper is a preliminary study on the management strategy of BLKPF on the basis of analyzing the characters of the ecosystems and the relative importance of services they provided in this region. Based on the latest research of ecosystem services of BLKPF in Changbai Mountain, an idea of eco-value level (EVL) was introduced, and accordingly, management strategies were summarized by adopting the advanced theories in ecosystem management science and by analyzing field survey data. EVL means the relative amount of the value of ecosystem services provided by certain ecosystem, which can indicate the difference between services in given objects. The EVL classification of BLKPF implies the relative amount of the eco-value of different ecosystems including virgin forest, secondary forest, forest with human disturbance, and man-made forest in the clear-cutting sites. Analytical Hierarchical Processing method was used to formulate the equation for EVL index. Eight factors, namely, slope, soil depth, stability of soil maternal material, coverage of above-ground canopy, species diversity, regeneration rate of the stand, life span of dominant tree species, and intensity of human disturbance were chosen to build the formula. These factors belonged to three aspects affecting ecosystem services including the physical environment, community, and

  17. The public water supply protection value of forests: A watershed-scale ecosystem services based upon total organic carbon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We developed a cost-based methodology to assess the value of forested watersheds to improve water quality in public water supplies. The developed methodology is applicable to other source watersheds to determine ecosystem services for water quality. We assess the value of forest land for source wate...

  18. Anthropogenic effects on forest ecosystems at various spatio-temporal scales.

    PubMed

    Bredemeier, Michael

    2002-03-27

    The focus in this review of long-term effects on forest ecosystems is on human impact. As a classification of this differentiated and complex matter, three domains of long-term effects with different scales in space and time are distinguished: Exploitation and conversion history of forests in areas of extended human settlement, Long-range air pollution and acid deposition in industrialized regions, Current global loss of forests and soil degradation. There is an evident link between the first and the third point in the list. Cultivation of primary forestland--with its tremendous effects on land cover--took place in Europe many centuries ago and continued for centuries. Deforestation today is a phenomenon predominantly observed in the developing countries, yet it threatens biotic and soil resources on a global scale. Acidification of forest soils caused by long-range air pollution from anthropogenic emission sources is a regional to continental problem in industrialized parts of the world. As a result of emission reduction legislation, atmospheric acid deposition is currently on the retreat in the richer industrialized regions (e.g., Europe, U.S., Japan); however, because many other regions of the world are at present rapidly developing their polluting industries (e.g., China and India), "acid rain" will most probably remain a serious ecological problem on regional scales. It is believed to have caused considerable destabilization of forest ecosystems, adding to the strong structural and biogeochemical impacts resulting from exploitation history. Deforestation and soil degradation cause the most pressing ecological problems for the time being, at least on the global scale. In many of those regions where loss of forests and soils is now high, it may be extremely difficult or impossible to restore forest ecosystems and soil productivity. Moreover, the driving forces, which are predominantly of a demographic and socioeconomic nature, do not yet seem to be lessening in

  19. Bryophyte-cyanobacteria associations contribute to ecosystem-N-budget of boreal forest

    NASA Astrophysics Data System (ADS)

    Salemaa, Maija; Lindroos, Antti-Jussi; Merilä, Päivi; Mäkipää, Raisa; Smolander, Aino

    2014-05-01

    Bryophytes frequently dominate the ground vegetation on the forest floor in boreal region. Northern ecosystems are often nitrogen limited, and therefore biological nitrogen (N2) fixation of bryophyte-associated microbes is an important source of new N. In this study we estimated the N stock of bryophyte layer and the N input rate by N2 fixation of bryophyte-cyanobacteria associations at the ecosystem level. We studied 12 intensively monitored forest ecosystem plots (ICP Forests Level II) along a latitudinal gradient in Finland during 2009-2013. The total biomass and N stock of the bryophytes varied 700-2000 kg ha-1 and 9-23 kg ha-1, respectively. N2 fixation rate associated to bryophytes increased towards the north and was at highest 1-2 kg N ha-1 year-1 (based on the bryophyte biomass in the monitoring plots). This N input was at the same level as the N deposition in the northern Finland (1.5 kg N ha-1 year-1). In comparison, via needle litterfall and other tree litter c.a. 5 kg N ha-1 is annually returned to the nutrient cycle. In southern Finland, very low rates of N2 fixation were found probably because of inhibition by the anthropogenic N deposition. The upper parts of the bryophyte shoots showed 2-3 times higher N2-fixing rate than the lower parts, but differences between Hylocomium splendens and Pleurozium schreberi were minor. However, Dicranum species showed much lower N2 fixation rates compared to these two species. The moisture level of bryophytes and light/temperature conditions regulated strongly the rate of N2-fixing activity. The results showed that the bryophyte layer significantly contributes to the N input and plays an important role in controlling the N and C balances of boreal forests.

  20. The spatial extent of change in tropical forest ecosystem services in the Amazon delta

    NASA Astrophysics Data System (ADS)

    de Araujo Barbosa, C. C.; Atkinson, P.; Dearing, J.

    2014-12-01

    Deltas hold major economic potential due their strategic location, close to seas and inland waterways, thereby supporting intense economic activity. The increasing pace of human development activities in coastal deltas over the past five decades has also strained environmental resources and produced extensive economic and sociocultural impacts. The Amazon delta is located in the Amazon Basin, North Brazil, the largest river basin on Earth and also one of the least understood. A considerable segment of the population living in the Amazon delta is directly dependent on the local extraction of natural resources for their livelihood. Areas sparsely inhabited may be exploited with few negative consequences for the environment. However, increasing pressure on ecosystem services is amplified by large fluxes of immigrants from other parts of the country, especially from the semi-arid zone in Northeast Brazil to the lowland forests of the Amazon delta. Here we present partial results from a bigger research project. Therefore, the focus will be on presenting an overview of the current state, and the extent of changes on forest related ecosystem services in the Amazon delta over the last three decades. We aggregated a multitude of datasets, from a variety of sources, for example, from satellite imagery such as the Advanced Very High Resolution Radiometer (AVHRR), the Global Inventory Modelling and Mapping Studies (GIMMS), the Moderate Resolution Imaging Spectroradiometer (MODIS), and climate datasets at meteorological station level from the Brazilian National Institute of Meteorology (INMET) and social and economic statistics data from the Brazilian Institute of Geography and Statistics (IBGE) and from the Brazilian Institute of Applied Economic Research (IPEA). Through analysis of socioeconomic and satellite earth observation data we were able to produce and present spatially-explicit information with the current state and transition in forest cover and its impacts to forest

  1. Harnessing ecosystem models and multi-criteria decision analysis for the support of forest management.

    PubMed

    Wolfslehner, Bernhard; Seidl, Rupert

    2010-12-01

    The decision-making environment in forest management (FM) has changed drastically during the last decades. Forest management planning is facing increasing complexity due to a widening portfolio of forest goods and services, a societal demand for a rational, transparent decision process and rising uncertainties concerning future environmental conditions (e.g., climate change). Methodological responses to these challenges include an intensified use of ecosystem models to provide an enriched, quantitative information base for FM planning. Furthermore, multi-criteria methods are increasingly used to amalgamate information, preferences, expert judgments and value expressions, in support of the participatory and communicative dimensions of modern forestry. Although the potential of combining these two approaches has been demonstrated in a number of studies, methodological aspects in interfacing forest ecosystem models (FEM) and multi-criteria decision analysis (MCDA) are scarcely addressed explicitly. In this contribution we review the state of the art in FEM and MCDA in the context of FM planning and highlight some of the crucial issues when combining ecosystem and preference modeling. We discuss issues and requirements in selecting approaches suitable for supporting FM planning problems from the growing body of FEM and MCDA concepts. We furthermore identify two major challenges in a harmonized application of FEM-MCDA: (i) the design and implementation of an indicator-based analysis framework capturing ecological and social aspects and their interactions relevant for the decision process, and (ii) holistic information management that supports consistent use of different information sources, provides meta-information as well as information on uncertainties throughout the planning process.

  2. Harnessing Ecosystem Models and Multi-Criteria Decision Analysis for the Support of Forest Management

    NASA Astrophysics Data System (ADS)

    Wolfslehner, Bernhard; Seidl, Rupert

    2010-12-01

    The decision-making environment in forest management (FM) has changed drastically during the last decades. Forest management planning is facing increasing complexity due to a widening portfolio of forest goods and services, a societal demand for a rational, transparent decision process and rising uncertainties concerning future environmental conditions (e.g., climate change). Methodological responses to these challenges include an intensified use of ecosystem models to provide an enriched, quantitative information base for FM planning. Furthermore, multi-criteria methods are increasingly used to amalgamate information, preferences, expert judgments and value expressions, in support of the participatory and communicative dimensions of modern forestry. Although the potential of combining these two approaches has been demonstrated in a number of studies, methodological aspects in interfacing forest ecosystem models (FEM) and multi-criteria decision analysis (MCDA) are scarcely addressed explicitly. In this contribution we review the state of the art in FEM and MCDA in the context of FM planning and highlight some of the crucial issues when combining ecosystem and preference modeling. We discuss issues and requirements in selecting approaches suitable for supporting FM planning problems from the growing body of FEM and MCDA concepts. We furthermore identify two major challenges in a harmonized application of FEM-MCDA: (i) the design and implementation of an indicator-based analysis framework capturing ecological and social aspects and their interactions relevant for the decision process, and (ii) holistic information management that supports consistent use of different information sources, provides meta-information as well as information on uncertainties throughout the planning process.

  3. Determination of Land Use/ Land Cover Changes in Igneada Alluvial (Longos) Forest Ecosystem, Turkey

    NASA Astrophysics Data System (ADS)

    Bektas Balcik, F.

    2012-12-01

    Alluvial (Longos) forests are one of the most fragile and threatened ecosystems in the world. Typically, these types of ecosystems have high biological diversity, high productivity, and high habitat dynamism. In this study, Igneada, Kirklareli was selected as study area. The region, lies between latitudes 41° 46' N and 41° 59' N and stretches between longitudes 27° 50' E and 28° 02' E and it covers approximately 24000 (ha). Igneada Longos ecosystems include mixed forests, streams, flooded (alluvial) forests, marshes, wetlands, lakes and coastal sand dunes with different types of flora and fauna. Igneada was classified by Conservation International as one of the world's top 122 Important Plant Areas, and 185 Important Bird Areas. These types of wild forest in other parts of Turkey and in Europe have been damaged due to anthropogenic effects. Remote sensing is very effective tool to monitor these types of sensitive regions for sustainable management. In this study, 1984 and 2011 dated Landsat 5 TM data were used to determine land cover/land use change detection of the selected region by using six vegetation indices such as Tasseled Cap index of greenness (TCG), brightness (TCB), and wetness (TCW), ratios of near-infrared to red image (RVI), normalized difference vegetation index (NDVI), and soil-adjusted vegetation index (SAVI). Geometric and radiometric corrections were applied in image pre-processing step. Selective Principle Component Analysis (PCA) change detection method was applied to the selected vegetation index imagery to generate change imagery for extracting the changed features between the year of 1984 and 2011. Accuracy assessment was applied based on error matrix by calculating overall accuracy and Kappa statistics.

  4. Estimation of fog deposition on epiphytic bryophytes in a subtropical montane forest ecosystem in northeastern Taiwan

    NASA Astrophysics Data System (ADS)

    Chang, Shih-Chieh; Lai, I.-Ling; Wu, Jiunn-Tzong

    The fog meteorology, fog chemistry and fog deposition on epiphytic bryophytes were investigated from July 2000 to June 2001 in the Yuanyang Lake forest ecosystem. The elevation of the site ranges from 1650 to 2420 m, at which the high frequency of fog occurrence throughout the year has been thought to be of benefit to the establishment of the primary Taiwan yellow cypress forest [ Chamaecyparis obtusa var. formosana (Hayata) Rehder] and to the extensive growth of the epiphytic bryophytes. A weather station including a visibility sensor and an active fog collector was installed for fog meteorological and chemical study. The fog deposition rate on epiphytic bryophytes was estimated by measuring the increase rate in plant weight when exposed to fog. Average fog duration of 4.7 and 11.0 h per day was measured in summer months (June to August) and the rest of the year, respectively. November 2000 was the foggiest month in which the average fog duration reached 14.9 h per day. The ionic composition of fog water revealed that the area was less polluted than expected from literature data. The in situ exposure experiments done with the dominant epiphytic bryophytes showed an average fog deposition rate of 0.63 g H 2O g -1 d. w. h -1, which approximated 0.17 mm h -1 at the stand scale. The nutrient fluxes estimated for February 2001 showed that for all ions, more than 50% of the ecosystem input was through fog deposition. These results demonstrate the importance of epiphytic bryophytes and fog deposition in nutrient cycling of this subtropical montane forest ecosystem. The incorporation of fog study in the long-term ecosystem research projects is necessary in this area.

  5. Belowground processes regulate ecosystem nitrogen retention during a multi-year forest dieback event

    NASA Astrophysics Data System (ADS)

    Nave, L. E.; Le Moine, J.; Gough, C. M.; Vogel, C.; Nadelhoffer, K. J.; Curtis, P.

    2013-12-01

    In the absence of disturbances, forests typically have strong retention capacity for nitrogen (N), which is internally recycled between soil, microbial and plant pools. However, disturbances that trigger senescence or mortality of forest vegetation may alter internal N cycling processes and lead to the loss of ecosystem N retention capacity. Here, we present an assessment of the role played by belowground processes in governing ecosystem N cycling and retention during an experimental disturbance that killed the dominant canopy taxa in a Great Lakes forest over a 4-year period. After applying stem girdling to hasten the age-related senescence of the dominant taxa (Populus and Betula spp.; ~35% of the basal area), we observed a 38% decrease in stand-level allocation of nonstructural carbohydrates to fine roots, which triggered a tenfold increase in the rate of fine root turnover and increased soil NH4+ and NO3- availability. Elevated soil N availability decreased mycorrhizal hyphal foraging and N uptake, effectively down-regulating the role of symbiotic fungi in the N nutrition of the residual (longer-lived) tree taxa. However, even as residual trees took up less N from mycorrhizal sources, their overall N uptake increased and served to offset the loss of the dominant taxa. The net result of this offset was that canopy N stocks remained constant through the disturbance period and there was no appreciable loss of ecosystem N stocks due to leaching or gaseous export. In sum, the cascade of changes in root, microbial, and soil processes during this experiment indicates that these interdependent components of the belowground system comprised a mechanism responsible for retention and redistribution of ecosystem N stocks during the disturbance period.

  6. Effects of introduced insects and diseases on forest ecosystems in the Catskill Mountains of New York.

    PubMed

    Lovett, Gary M; Arthur, Mary A; Weathers, Kathleen C; Griffin, Jacob M

    2013-09-01

    Repeated invasions of non-native insects and pathogens have altered the structure and function of forest ecosystems in the Catskill Mountains of New York State, and will continue to do so in the future. Gypsy moth, beech bark disease, and hemlock woolly adelgid are among the insects and diseases currently established in the Catskills that are having significant effects on forests. Many others, including emerald ash borer, Asian long-horned beetle, Phytophthora ramorum, and Sirex wood wasp, are either very recently established in the Catskills or have been found elsewhere in North America and threaten to spread to this region. Short-term disturbances associated with these pests include reduction of productivity, tree decline and mortality, disruption of nutrient cycles, and reduction of seed production. Longer-term impacts are associated with shifts in tree species composition that alter productivity, nutrient cycling, and biodiversity. Catskill forests at mid to high elevations, such as the New York State Forest Preserve lands, are dominated by sugar maple and are particularly vulnerable to pests that use maple as a host, including the Asian long-horned beetle. The simultaneous effects of multiple invading insects and pathogens, and their interactions with changing climate and air pollution regimes, make it very difficult to predict the future composition of Catskill forests.

  7. Relating injury to the forest ecosystem near Palmerton, PA, to zinc contamination from smelting

    USGS Publications Warehouse

    Beyer, W. Nelson; Krafft, Cairn; Klassen, Stephen; Green, Carrie E.; Chaney, Rufus L.

    2011-01-01

    The forest on Blue Mountain, near Lehigh Gap, has been injured by emissions from two historical zinc (Zn) smelters in Palmerton, PA, located at the northern base of the mountain. The uppermost mineral soil and lower litter from sites along a transect, just south of the ridgetop, contained from 64 to 4400 mg/kg Zn. We measured forest metrics at 15 sampling sites to ascertain how forest structure, species composition and regeneration are related to soil concentrations of Zn, the probable principal cause of the injury. Understanding how ecotoxicological injury is related to soil Zn concentrations helps us quantify the extent of injury to the ecosystem on Blue Mountain as well as to generalize to other sites. The sum of canopy closure and shrub cover, suggested as a broadly inclusive measure of forest structure, was decreased to half at approximately 2060 mg/kg Zn (102 mg/kg Sr(N03)2-extractable Zn). Tree-seedling density was decreased by 80% (from 10.5/m2 to 2.1/m2) at a much lower concentration: 1080 mg/kg Zn (59 mg/kg Sr(N03)2-extractable Zn). Changes in species composition and richness were not as useful for quantifying injury to the forest. Phytotoxicity, desiccation from exposure, and a gypsy moth infestation combined to form a barren area on the ridgetop. Liming the strongly acid Hazleton soils at the sites would partially ameliorate the observed phytotoxicity and should be considered in planning restoration.

  8. [Dynamic Characteristics of Base Cations During Wet Deposition in Evergreen Broad-leaf Forest Ecosystem].

    PubMed

    An, Si-wei; Sun, Tao; Ma, Ming; Wang, Ding-yong

    2015-12-01

    Based on field tests and laboratory experiments, effects of precipitation, throughfall, litterfall, and groundwater runoff of the ever-green broad-leaf forest on the dynamic characteristics of base cations in Simian Mountain were investigated from September 2012 to August 2013. The results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.90 and maximum pH of 5.14. The soil and canopies could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy only had the function of interception on Na⁺. And precipitation could leach out Ca2⁺, Mg2⁺ and K⁺ of the canopies. Moreover, the degradation of litter was probably the main reason for the increase of base cations concentrations in the surface litter water. The litter water leached Ca2⁺, Mg2⁺ and Na⁺ of the forest soil through downward infiltration. The total retention rates of Ca²⁺, Mg²⁺, Na⁺ and K⁺ were 33.82%, -7.06%, 74.36% and 42.87%, respectively. Ca²⁺, Na⁺, K⁺ were found to be reserved in the forest ecosystem, and the highest interception rate was found for Na⁺. PMID:27011975

  9. [Dynamic Characteristics of Base Cations During Wet Deposition in Evergreen Broad-leaf Forest Ecosystem].

    PubMed

    An, Si-wei; Sun, Tao; Ma, Ming; Wang, Ding-yong

    2015-12-01

    Based on field tests and laboratory experiments, effects of precipitation, throughfall, litterfall, and groundwater runoff of the ever-green broad-leaf forest on the dynamic characteristics of base cations in Simian Mountain were investigated from September 2012 to August 2013. The results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.90 and maximum pH of 5.14. The soil and canopies could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy only had the function of interception on Na⁺. And precipitation could leach out Ca2⁺, Mg2⁺ and K⁺ of the canopies. Moreover, the degradation of litter was probably the main reason for the increase of base cations concentrations in the surface litter water. The litter water leached Ca2⁺, Mg2⁺ and Na⁺ of the forest soil through downward infiltration. The total retention rates of Ca²⁺, Mg²⁺, Na⁺ and K⁺ were 33.82%, -7.06%, 74.36% and 42.87%, respectively. Ca²⁺, Na⁺, K⁺ were found to be reserved in the forest ecosystem, and the highest interception rate was found for Na⁺.

  10. Effects of introduced insects and diseases on forest ecosystems in the Catskill Mountains of New York.

    PubMed

    Lovett, Gary M; Arthur, Mary A; Weathers, Kathleen C; Griffin, Jacob M

    2013-09-01

    Repeated invasions of non-native insects and pathogens have altered the structure and function of forest ecosystems in the Catskill Mountains of New York State, and will continue to do so in the future. Gypsy moth, beech bark disease, and hemlock woolly adelgid are among the insects and diseases currently established in the Catskills that are having significant effects on forests. Many others, including emerald ash borer, Asian long-horned beetle, Phytophthora ramorum, and Sirex wood wasp, are either very recently established in the Catskills or have been found elsewhere in North America and threaten to spread to this region. Short-term disturbances associated with these pests include reduction of productivity, tree decline and mortality, disruption of nutrient cycles, and reduction of seed production. Longer-term impacts are associated with shifts in tree species composition that alter productivity, nutrient cycling, and biodiversity. Catskill forests at mid to high elevations, such as the New York State Forest Preserve lands, are dominated by sugar maple and are particularly vulnerable to pests that use maple as a host, including the Asian long-horned beetle. The simultaneous effects of multiple invading insects and pathogens, and their interactions with changing climate and air pollution regimes, make it very difficult to predict the future composition of Catskill forests. PMID:23844706

  11. Net Ecosystem Fluxes of Hydrocarbons from a Ponderosa Pine Forest in Colorado

    NASA Astrophysics Data System (ADS)

    Rhew, R. C.; Turnipseed, A. A.; Ortega, J. V.; Smith, J. N.; Guenther, A. B.; Shen, S.; Martinez, L.; Koss, A.; Warneke, C.; De Gouw, J. A.; Deventer, M. J.

    2015-12-01

    Light (C2-C4) alkenes, light alkanes and isoprene (C5H8) are non-methane hydrocarbons that play important roles in the photochemical production of tropospheric ozone and in the formation of secondary organic aerosols. Natural terrestrial fluxes of the light hydrocarbons are poorly characterized, with global emission estimates based on limited field measurements. In 2014, net fluxes of these compounds were measured at the Manitou Experimental Forest Observatory, a semi-arid ponderosa pine forest in the Colorado Rocky Mountains and site of the prior BEACHON campaigns. Three field intensives were conducted between June 17 and August 10, 2014. Net ecosystem flux measurements utilized a relaxed eddy accumulation system coupled to an automated gas chromatograph. Summertime average emissions of ethene and propene were up to 90% larger than those observed from a temperate deciduous forest. Ethene and propene fluxes were also correlated to each other, similar to the deciduous forest study. Emissions of isoprene were small, as expected for a coniferous forest, and these fluxes were not correlated with either ethene or propene. Unexpected emissions of light alkanes were also observed, and these showed a distinct diurnal cycle. Understory flux measurements allowed for the partitioning of fluxes between the surface and the canopy. Full results from the three field intensives will be compared with environmental variables in order to parameterize the fluxes for use in modeling emissions.

  12. The OpenForest Portal as an Open Learning Ecosystem: Co-Developing in the Study of a Multidisciplinary Phenomenon in a Cultural Context

    ERIC Educational Resources Information Center

    Liljeström, Anu; Enkenberg, Jorma; Vanninen, Petteri; Vartiainen, Henriikka; Pöllänen, Sinikka

    2014-01-01

    This paper discusses the OpenForest portal and its related multidisciplinary learning project. The OpenForest portal is an open learning environment and ecosystem, in which students can participate in co-developing and co-creating practices. The aim of the OpenForest ecosystem is to create an extensive interactive network of diverse learning…

  13. Quantifying Forest Ecosystem Services Tradeoff—Coupled Ecological and Economic Models

    NASA Astrophysics Data System (ADS)

    Haff, P. K.; Ling, P. Y.

    2015-12-01

    Quantification of the effect of carbon-related forestland management activities on ecosystem services is difficult, because knowledge about the dynamics of coupled social-ecological systems is lacking. Different forestland management activities, such as various amount, timing, and methods of harvesting, and natural disturbances events, such as wind and fires, create shocks and uncertainties to the forest carbon dynamics. A spatially explicit model, Landis-ii, was used to model the forest succession for different harvest management scenarios at the Grandfather District, North Carolina. In addition to harvest, the model takes into account of the impact of natural disturbances, such as fire and insects, and species competition. The result shows the storage of carbon in standing biomass and in wood product for each species for each scenario. In this study, optimization is used to analyze the maximum profit and the number of tree species that each forest landowner can gain at different prices of carbon, roundwood, and interest rates for different harvest management scenarios. Time series of roundwood production of different types were estimated using remote sensing data. Econometric analysis is done to understand the possible interaction and relations between the production of different types of roundwood and roundwood prices, which can indicate the possible planting scheme that a forest owner may make. This study quantifies the tradeoffs between carbon sequestration, roundwood production, and forest species diversity not only from an economic perspective, but also takes into account of the forest succession mechanism in a species-diverse region. The resulting economic impact on the forest landowners is likely to influence their future planting decision, which in turn, will influence the species composition and future revenue of the landowners.

  14. Regional extent of an ecosystem engineer: earthworm invasion in northern hardwood forests.

    PubMed

    Holdsworth, Andrew R; Frelich, Lee E; Reich, Peter B

    2007-09-01

    The invasion of exotic earthworms into northern temperate and boreal forests previously devoid of earthworms is an important driver of ecosystem change. Earthworm invasion can cause significant changes in soil structure and communities, nutrient cycles, and the diversity and abundance of herbaceous plants. However, the regional extent and patterns of this invasion are poorly known. We conducted a regional survey in the Chippewa and Chequamegon National Forests, in Minnesota and Wisconsin, U.S.A., respectively, to measure the extent and patterns of earthworm invasion and their relationship to potential earthworm introduction sites. We sampled earthworms, soils, and vegetation in 20 mature, sugar maple-dominated forest stands in each national forest and analyzed the relationship between the presence of five earthworm taxonomic groups, habitat variables, and distance to the nearest potential introduction site. Earthworm invasion was extensive but incomplete in the two national forests. Four of the six earthworm taxonomic groups occurred in 55-95% of transects; however 20% of all transects were invaded by only one taxonomic group that has relatively minor ecological effects. Earthworm taxonomic groups exhibited a similar sequence of invasion found in other studies: Dendrobaena > Aporrectodea = Lumbricus juveniles > L. rubellus > L. terrestris. Distance to the nearest road was the best predictor of earthworm invasion in Wisconsin while distance to the nearest cabin was the best predictor in Minnesota. These data allow us to make preliminary assessments of landscape patterns of earthworm invasion. As an example, we estimate that 82% of upland mesic hardwood stands in the Wisconsin region are likely invaded by most taxonomic groups while only 3% are unlikely to be invaded at present. Distance to roads and cabins provides a coarse-scale predictor of earthworm invasion to focus stand-level assessments that will help forest managers better understand current and potential

  15. Ecosystem services of boreal forests - Carbon budget mapping at high resolution.

    PubMed

    Akujärvi, Anu; Lehtonen, Aleksi; Liski, Jari

    2016-10-01

    The carbon (C) cycle of forests produces ecosystem services (ES) such as climate regulation and timber production. Mapping these ES using simple land cover -based proxies might add remarkable inaccuracy to the estimates. A framework to map the current status of the C budget of boreal forested landscapes was developed. The C stocks of biomass and soil and the annual change in these stocks were quantified in a 20 × 20 m resolution at the regional level on mineral soils in southern Finland. The fine-scale variation of the estimates was analyzed geo-statistically. The reliability of the estimates was evaluated by comparing them to measurements from the national multi-source forest inventory. The C stocks of forests increased slightly from the south coast to inland whereas the changes in these stocks were more uniform. The spatial patches of C stocks were larger than those of C stock changes. The patch size of the C stocks reflected the spatial variation in the environmental conditions, and that of the C stock changes the typical area of forest management compartments. The simulated estimates agreed well with the measurements indicating a good mapping framework performance. The mapping framework is the basis for evaluating the effects of forest management alternatives on C budget at high resolution across large spatial scales. It will be coupled with the assessment of other ES and biodiversity to study their relationships. The framework integrated a wide suite of simulation models and extensive inventory data. It provided reliable estimates of the human influence on C cycle in forested landscapes. PMID:27420172

  16. Dynamics of novel forests of Castilla elastica in Puerto Rico: from species to ecosystems.

    PubMed

    Fonseca da Silva, Jéssica

    2015-08-01

    Novel forests (NFs)-forests that contain a combination of introduced and native species-are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the performance of individual species in those forests. This study focuses on the functional attributes of Castilla elastica NFs in Puerto Rico and on the differences between introduced and native species growing side by side in these forests. Rates of processes measured here were later compared with data from literature about NSFs. I hypothesize that juvenile plants of C. elastica in NFs have higher survival rate than those of native species and that C. elastica trees have faster biomass fluxes than native trees. To test the hypotheses, I measured survival rates of juvenile plants and tree growth and characterized the aboveground litter fluxes and storage. Although juvenile plants of native species displayed higher survival rates than those of C. elastica (53% vs. 28%), the latter was dominant in the understory (96%). Stand biomass growth rate was 2.0 ± 0.4 (average ± one standard deviation) Mg·ha(-1)·year(-1) for the whole forest, and Guarea guidonia, a native species, exhibited the highest tree growth. Total litter fall was 9.6 ± 0.5 Mg·ha(-1)·year(-1), and mean litter standing stock was 4.4 ± 0.1 Mg·ha(-1). Castilla elastica litter fall decomposed twice as fast as that of native species (5.8 ± 1.1 vs. 3.03 ± 1 k·year(-1)). Literature comparisons show that the present NFs differ in some rates of processes from NSFs. This study brings unique and detailed supporting data about the ecological dynamics under mature novel forest stands. Further comprehensive studies about NFs are important to strengthen the body of knowledge about the wide range of variation of emerging tropical ecosystems. Due to the

  17. Dynamics of novel forests of Castilla elastica in Puerto Rico: from species to ecosystems.

    PubMed

    Fonseca da Silva, Jéssica

    2015-08-01

    Novel forests (NFs)-forests that contain a combination of introduced and native species-are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the performance of individual species in those forests. This study focuses on the functional attributes of Castilla elastica NFs in Puerto Rico and on the differences between introduced and native species growing side by side in these forests. Rates of processes measured here were later compared with data from literature about NSFs. I hypothesize that juvenile plants of C. elastica in NFs have higher survival rate than those of native species and that C. elastica trees have faster biomass fluxes than native trees. To test the hypotheses, I measured survival rates of juvenile plants and tree growth and characterized the aboveground litter fluxes and storage. Although juvenile plants of native species displayed higher survival rates than those of C. elastica (53% vs. 28%), the latter was dominant in the understory (96%). Stand biomass growth rate was 2.0 ± 0.4 (average ± one standard deviation) Mg·ha(-1)·year(-1) for the whole forest, and Guarea guidonia, a native species, exhibited the highest tree growth. Total litter fall was 9.6 ± 0.5 Mg·ha(-1)·year(-1), and mean litter standing stock was 4.4 ± 0.1 Mg·ha(-1). Castilla elastica litter fall decomposed twice as fast as that of native species (5.8 ± 1.1 vs. 3.03 ± 1 k·year(-1)). Literature comparisons show that the present NFs differ in some rates of processes from NSFs. This study brings unique and detailed supporting data about the ecological dynamics under mature novel forest stands. Further comprehensive studies about NFs are important to strengthen the body of knowledge about the wide range of variation of emerging tropical ecosystems. Due to the

  18. Dynamics of novel forests of Castilla elastica in Puerto Rico: from species to ecosystems

    PubMed Central

    Fonseca da Silva, Jéssica

    2015-01-01

    Novel forests (NFs)—forests that contain a combination of introduced and native species—are a consequence of intense anthropogenic disturbances and the natural resilience of disturbed ecosystems. The extent to which NFs have similar forest function as comparable native secondary forests is a matter of debate in the scientific community. Little is known about the performance of individual species in those forests. This study focuses on the functional attributes of Castilla elastica NFs in Puerto Rico and on the differences between introduced and native species growing side by side in these forests. Rates of processes measured here were later compared with data from literature about NSFs. I hypothesize that juvenile plants of C. elastica in NFs have higher survival rate than those of native species and that C. elastica trees have faster biomass fluxes than native trees. To test the hypotheses, I measured survival rates of juvenile plants and tree growth and characterized the aboveground litter fluxes and storage. Although juvenile plants of native species displayed higher survival rates than those of C. elastica (53% vs. 28%), the latter was dominant in the understory (96%). Stand biomass growth rate was 2.0 ± 0.4 (average ± one standard deviation) Mg·ha−1·year−1 for the whole forest, and Guarea guidonia, a native species, exhibited the highest tree growth. Total litter fall was 9.6 ± 0.5 Mg·ha−1·year−1, and mean litter standing stock was 4.4 ± 0.1 Mg·ha−1. Castilla elastica litter fall decomposed twice as fast as that of native species (5.8 ± 1.1 vs. 3.03 ± 1 k·year−1). Literature comparisons show that the present NFs differ in some rates of processes from NSFs. This study brings unique and detailed supporting data about the ecological dynamics under mature novel forest stands. Further comprehensive studies about NFs are important to strengthen the body of knowledge about the wide range of variation of emerging tropical ecosystems. Due to

  19. Tree Species Linked to Large Differences in Ecosystem Carbon Distribution in the Boreal Forest of Alaska

    NASA Astrophysics Data System (ADS)

    Melvin, A. M.; Mack, M. C.; Johnstone, J. F.; Schuur, E. A. G.; Genet, H.; McGuire, A. D.

    2014-12-01

    In the boreal forest of Alaska, increased fire severity associated with climate change is altering plant-soil-microbial feedbacks and ecosystem carbon (C) dynamics. The boreal landscape has historically been dominated by black spruce (Picea mariana), a tree species associated with slow C turnover and large soil organic matter (SOM) accumulation. Historically, low severity fires have led to black spruce regeneration post-fire, thereby maintaining slow C cycling rates and large SOM pools. In recent decades however, an increase in high severity fires has led to greater consumption of the soil organic layer (SOL) during fire and subsequent establishment of deciduous tree species in areas previously dominated by black spruce. This shift to a more deciduous dominated landscape has many implications for ecosystem structure and function, as well as feedbacks to global C cycling. To improve our understanding of how boreal tree species affect C cycling, we quantified above- and belowground C stocks and fluxes in adjacent, mid-successional stands of black spruce and Alaska paper birch (Betula neoalaskana) that established following a 1958 fire near Fairbanks, Alaska. Although total ecosystem C pools (aboveground live tree biomass + dead wood + SOL + top 10 cm of mineral soil) were similar for the two stand types, the distribution of C among pools was markedly different. In black spruce, 78% of measured C was found in soil pools, primarily in the SOL, where spruce contained twice the C stored in paper birch (4.8 ± 0.3 vs. 2.4 ± 0.1 kg C m-2). In contrast, aboveground biomass dominated ecosystem C pools in birch forest (6.0 ± 0.3 vs. 2.5 ± 0.2 kg C m-2 in birch and spruce, respectively). Our findings suggest that tree species exert a strong influence over plant-soil-microbial feedbacks and may have long-term effects on ecosystem C sequestration and storage that feedback to the climate system.

  20. Analysis of neighborhood dynamics of forest ecosystems using likelihood methods and modeling.

    PubMed

    Canham, Charles D; Uriarte, María

    2006-02-01

    Advances in computing power in the past 20 years have led to a proliferation of spatially explicit, individual-based models of population and ecosystem dynamics. In forest ecosystems, the individual-based models encapsulate an emerging theory of "neighborhood" dynamics, in which fine-scale spatial interactions regulate the demography of component tree species. The spatial distribution of component species, in turn, regulates spatial variation in a whole host of community and ecosystem properties, with subsequent feedbacks on component species. The development of these models has been facilitated by development of new methods of analysis of field data, in which critical demographic rates and ecosystem processes are analyzed in terms of the spatial distributions of neighboring trees and physical environmental factors. The analyses are based on likelihood methods and information theory, and they allow a tight linkage between the models and explicit parameterization of the models from field data. Maximum likelihood methods have a long history of use for point and interval estimation in statistics. In contrast, likelihood principles have only more gradually emerged in ecology as the foundation for an alternative to traditional hypothesis testing. The alternative framework stresses the process of identifying and selecting among competing models, or in the simplest case, among competing point estimates of a parameter of a model. There are four general steps involved in a likelihood analysis: (1) model specification, (2) parameter estimation using maximum likelihood methods, (3) model comparison, and (4) model evaluation. Our goal in this paper is to review recent developments in the use of likelihood methods and modeling for the analysis of neighborhood processes in forest ecosystems. We will focus on a single class of processes, seed dispersal and seedling dispersion, because recent papers provide compelling evidence of the potential power of the approach, and illustrate

  1. Kinetic energy of throughfall in a highly diverse forest ecosystem in the humid subtropics

    NASA Astrophysics Data System (ADS)

    Geißler, Christian; Kühn, Peter; Scholten, Thomas

    2010-05-01

    After decades of research it is generally accepted that vegetation is a key factor in controlling soil erosion. Therefore, in ecosystems where erosion is a serious problem, afforestation is a common measure against erosion. Most of the studies in the last decades focused on agricultural systems and less attention was paid to natural systems. To understand the mechanisms preventing soil erosion in natural systems the processes have to be studied in detail and gradually. The first step and central research question is on how the canopies of the tree layer alter the properties of rainfall and generate throughfall. Kinetic energy is a widely used parameter to estimate the erosion potential of open field rainfall and throughfall. In the past, numerous studies have shown that vegetation of a certain height enhances the kinetic energy under the canopy (Chapman 1948, Mosley 1982, Vis 1986, Hall & Calder 1993, Nanko et al. 2006, Nanko et al. 2008) in relation to open field rainfall. This is mainly due to a shift in the drop size distribution to less but larger drops possessing a higher amount of kinetic energy. In vital forest ecosystems lower vegetation (shrubs, herbs) as well as a continuous litter layer protects the forest soil from the impact of large drops. The influence of biodiversity, specific forest stands or single species in this process system is still in discussion. In the present study calibrated splash cups (after Ellison 1947, Geißler et al. under review) have been used to detect differences in kinetic energy on the scale of specific species and on the scale of forest stands of contrasting age and biodiversity in a natural forest ecosystem. The splash cups have been calibrated experimentally using a laser disdrometer. The results show that the kinetic energy of throughfall produced by the tree layer increases with the age of the specific forest stand. The average throughfall kinetic energy (J m-2) is about 2.6 times higher in forests than under open field

  2. Foundation species loss affects vegetation structure more than ecosystem function in a northeastern USA forest.

    PubMed

    Orwig, David A; Barker Plotkin, Audrey A; Davidson, Eric A; Lux, Heidi; Savage, Kathleen E; Ellison, Aaron M

    2013-01-01

    Loss of foundation tree species rapidly alters ecological processes in forested ecosystems. Tsuga canadensis, an hypothesized foundation species of eastern North American forests, is declining throughout much of its range due to infestation by the nonnative insect Adelges tsugae and by removal through pre-emptive salvage logging. In replicate 0.81-ha plots, T. canadensis was cut and removed, or killed in place by girdling to simulate adelgid damage. Control plots included undisturbed hemlock and mid-successional hardwood stands that represent expected forest composition in 50-100 years. Vegetation richness, understory vegetation cover, soil carbon flux, and nitrogen cycling were measured for two years prior to, and five years following, application of experimental treatments. Litterfall and coarse woody debris (CWD), including snags, stumps, and fallen logs and branches, have been measured since treatments were applied. Overstory basal area was reduced 60%-70% in girdled and logged plots. Mean cover and richness did not change in hardwood or hemlock control plots but increased rapidly in girdled and logged plots. Following logging, litterfall immediately decreased then slowly increased, whereas in girdled plots, there was a short pulse of hemlock litterfall as trees died. CWD volume remained relatively constant throughout but was 3-4× higher in logged plots. Logging and girdling resulted in small, short-term changes in ecosystem dynamics due to rapid regrowth of vegetation but in general, interannual variability exceeded differences among treatments. Soil carbon flux in girdled plots showed the strongest response: 35% lower than controls after three years and slowly increasing thereafter. Ammonium availability increased immediately after logging and two years after girdling, due to increased light and soil temperatures and nutrient pulses from leaf-fall and reduced uptake following tree death. The results from this study illuminate ecological processes underlying

  3. Faunal impact on vegetation structure and ecosystem function in mangrove forests: A review

    USGS Publications Warehouse

    Cannicci, Stefano; Burrows, Damien; Fratini, Sara; Smith, Thomas J.; Offenberg, Joachim; Dahdouh-Guebas, Farid

    2008-01-01

    The last 20 years witnessed a real paradigm shift concerning the impact of biotic factors on ecosystem functions as well as on vegetation structure of mangrove forests. Before this small scientific revolution took place, structural aspects of mangrove forests were viewed to be the result of abiotic processes acting from the bottom-up, while, at ecosystem level, the outwelling hypothesis stated that mangroves primary production was removed via tidal action and carried to adjacent nearshore ecosystems where it fuelled detrital based food-webs. The sesarmid crabs were the first macrofaunal taxon to be considered a main actor in mangrove structuring processes, thanks to a number of studies carried out in the Indo-Pacific forests in the late 1970s and early 1980s. Following these classical papers, a number of studies on Sesarmidae feeding and burrowing ecology were carried out, which leave no doubts about the great importance of these herbivorous crabs in structuring and functioning Old world ecosystems. Although Sesarmidae are still considered very important in shaping mangrove structure and functioning, recent literature emphasizes the significance of other invertebrates. The Ocypodidae have now been shown to have the same role as Sesarmidae in terms of retention of forest products and organic matter processing in New world mangroves. In both New and Old world mangroves, crabs process large amounts of algal primary production, contribute consistently to retention of mangrove production and as ecosystem engineers, change particle size distribution and enhance soil aeration. Our understanding of the strong impact of gastropods, by means of high intake rates of mangrove products and differential consumption of propagules, has changed only recently. The role of insects must also be stressed. It is now clear that older techniques used to assess herbivory rates by insects strongly underestimate their impact, both in case of leaf eating and wood boring species and that

  4. Forest to reclaimed mine land use change leads to altered ecosystem structure and function

    SciTech Connect

    Simmons, J.A.; Currie, W.S.; Eshleman, K.N.; Kuers, K.; Monteleone, S.; Negley, T.L.; Pohlad, B.R.; Thomas, C.L.

    2008-01-15

    The United States' use of coal results in many environmental alterations. In the Appalachian coal belt region, one widespread alteration is conversion of forest to reclaimed mineland. The goal of this study was to quantify the changes to ecosystem structure and function associated with a conversion from forest to reclaimed mine grassland by comparing a small watershed containing a 15-year-old reclaimed mine with a forested, reference watershed in western Maryland. Major differences were apparent between the two watersheds in terms of biogeochemistry. Total C, N, and P pools were all substantially lower at the mined site, mainly due to the removal of woody biomass but also, in the case of P, to reductions in soil pools. Mineral soil C, N, and P pools were 96%, 79%, and 69% of native soils, respectively. Although annual runoff from the watersheds was similar, the mined watershed exhibited taller, narrower storm peaks as a result of a higher soil bulk density and decreased infiltration rates. Stream export of N was much lower in the mined watershed due to lower net nitrification rates and nitrate concentrations in soil. However, stream export of sediment and P and summer stream temperature were much higher. Stream leaf decomposition was reduced and macroinvertebrate community structure was altered as a result of these changes to the stream environment. This land use change leads to substantial, long-term changes in ecosystem capital and function.

  5. Species interactions regulate the collapse of biodiversity and ecosystem function in tropical forest fragments.

    PubMed

    Bregman, Tom P; Lees, Alexander C; Seddon, Nathalie; Macgregor, Hannah E A; Darski, Bianca; Aleixo, Alexandre; Bonsall, Michael B; Tobias, Joseph A

    2015-10-01

    Competitive interactions among species with similar ecological niches are known to regulate the assembly of biological communities. However, it is not clear whether such forms of competition can predict the collapse of communities and associated shifts in ecosystem function in the face of environmental change. Here, we use phylogenetic and functional trait data to test whether communities of two ecologically important guilds of tropical birds (frugivores and insectivores) are structured by species interactions in a fragmented Amazonian forest landscape. In both guilds, we found that forest patch size, quality, and degree of isolation influence the phylogenetic and functional trait structure of communities, with small, degraded, or isolated forest patches having an increased signature of competition (i.e., phylogenetic and functional trait overdispersion in relation to null models). These results suggest that local extinctions in the context of fragmentation are nonrandom, with a consistent bias toward more densely occupied regions of niche space. We conclude that the loss of biodiversity in fragmented landscapes is mediated by niche-based competitive interactions among species, with potentially far-reaching implications for key ecosystem processes, including seed dispersal and plant damage by phytophagous insects. PMID:26649390

  6. Species interactions regulate the collapse of biodiversity and ecosystem function in tropical forest fragments.

    PubMed

    Bregman, Tom P; Lees, Alexander C; Seddon, Nathalie; Macgregor, Hannah E A; Darski, Bianca; Aleixo, Alexandre; Bonsall, Michael B; Tobias, Joseph A

    2015-10-01

    Competitive interactions among species with similar ecological niches are known to regulate the assembly of biological communities. However, it is not clear whether such forms of competition can predict the collapse of communities and associated shifts in ecosystem function in the face of environmental change. Here, we use phylogenetic and functional trait data to test whether communities of two ecologically important guilds of tropical birds (frugivores and insectivores) are structured by species interactions in a fragmented Amazonian forest landscape. In both guilds, we found that forest patch size, quality, and degree of isolation influence the phylogenetic and functional trait structure of communities, with small, degraded, or isolated forest patches having an increased signature of competition (i.e., phylogenetic and functional trait overdispersion in relation to null models). These results suggest that local extinctions in the context of fragmentation are nonrandom, with a consistent bias toward more densely occupied regions of niche space. We conclude that the loss of biodiversity in fragmented landscapes is mediated by niche-based competitive interactions among species, with potentially far-reaching implications for key ecosystem processes, including seed dispersal and plant damage by phytophagous insects.

  7. N-15 tracing helps explaining N leaching losses from contrasting forest ecosystems

    NASA Astrophysics Data System (ADS)

    Staelens, J.; Rütting, T.; Huygens, D.; Müller, C.; Verheyen, K.; Boeckx, P.

    2009-04-01

    Despite chronically enhanced nitrogen (N) deposition to forest ecosystems in Europe and NE America, considerable N retention by forests has been observed, reducing N leaching losses. Organic and mineral soil layers typically immobilize more N than the aboveground biomass, but it is unclear which factors determine N retention in forest ecoystems. However, this knowledge is crucial to assess the impact of changing anthropogenic N emissions on future N cycling and N loss of forests. For coniferous and deciduous forest stands at comparable sites, it is known that both N deposition onto the forest floor as well as N loss by leaching below the rooting zone are significantly higher in coniferous stands. In addition, the N loss in coniferous stands is often more enhanced than can be explained by the higher N input only. This suggests lower N retention by coniferous stands, and may be related to differences in litter and soil characteristics, microbial activity, and N uptake by plant roots. To test this hypothesis, we studied the effect of forest type on N retention using 15N tracing techniques: a field tracer experiment and a combination of in situ isotope pool dilution and a tracing model. The N dynamics were examined for two adjacent forest stands (pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.)) on a well-drained sandy soil and with a similar stand history, located in a region with high N deposition (Belgium). Input-output N budgets were established by quantifying atmospheric deposition and leaching below the rooting zone, and confirmed the above finding of higher N deposition and disproportionately higher N loss for the pine stand compared to the oak stand. First, the fate of inorganic N within the ecosystems was studied by spraying three pulses of dissolved 15N, either as ammonium or as nitrate, onto the forest floor in 12 plots of 25 m2. The organic and mineral soil layers, tree roots, soil water percolate, ferns, and tree foliage were sampled

  8. Projected dynamics of abiotic risks in boreal forest ecosystems (SRES A1B, B1)

    NASA Astrophysics Data System (ADS)

    Panferov, O.; Ahrends, B.; Doering, C.; Sogachev, A.

    2009-04-01

    The ongoing climate change causes an increasing frequency of weather extremes (Leckebusch et al., 2008), which can result in wide area damage events (drought, windthrows/breaks) within boreal forest ecosystem. The damage effects, however, depend not only on the strength of a driving force itself (e.g. wind speed) but also on combinations of effecting agents and forest structure. Thus, the present study investigates the projected future developments of abiotic risks in different boreal forests during the 21st Century under conditions of SRES scenarios A1B and B1. Climate scenario data of coupled ECHAM5-MPIOM were downscaled by the regional climate model (CLM) to the spatial resolution of 0.2° x 0.2°, using daily time- steps. With these input data the small-scale modelling with coupled process based sub-models (Jansen et al., 2008) was carried out e.g. for Solling region, (Germany) calculating the water and energy balance of forest ecosystems with modified BROOK 90 (Ahrends et al., 2009) and wind loading on trees with 3D ABL model SCADIS (Panferov and Sogachev, 2008). Norway spruce and Scots pine of various ages were chosen as typical tree species for boreal forest ecosystems and cambisols, podzolic cambisols and stagnosols as typical soil types. The risks of drought and windthrow/breaks for a certain forest stand result from daily combinations of soil water characteristics, static and gust wind loads and soil texture. Damaged stands show higher vulnerability and thus - positive feedback to climate forcing (Vygodskaya et al., 2008). Therefore differences of microclimatological conditions in the remaining stand after changes in forest structure (Radler et al, 2008) were taken into account. Modell output was aggregated to 30-years periods and compared to "present conditions" of 1981-2010. The results show an increment of drought risks towards 2100 caused by changes in precipitation pattern and increase of mean air temperature, whereas the A1B scenario is

  9. Contrasting responses of forest ecosystems to rising atmospheric CO2: Implications for the global C cycle

    SciTech Connect

    Norby, Richard J; DeLucia, E. H.; Moore, D J

    2005-01-01

    In two parallel but independent experiments, Free Air CO2 Enrichment (FACE) technology was used to expose plots within contrasting evergreen loblolly pine (Pinus taeda L.) and deciduous sweetgum (Liquidambar styraciflua L.) forests to the level of CO2 anticipated in 2050. Net primary production (NPP) and net ecosystem production (NEP) increased in both forests. In the year 2000, after exposing pine and sweetgum to elevated CO2 for approximately 5 and 3 years, a complete budget calculation revealed increases in net ecosystem production (NEP) of 41% and 44% in the pine forest and sweetgum forest, respectively, representing the storage of an additional 174 gC m-2 and 128 gC m-2 in these forests. The stimulation of NPP without corresponding increases in leaf area index or light absorption in either forest resulted in 23-27% stimulation in radiation-use efficiency, defined as NPP per unit absorbed photosynthetically active radiation. Greater plant respiration contributed to lower NPP in the loblolly pine forest than in the sweetgum forest, and these forests responded differently to CO2 enrichment. Where the pine forest added C primarily to long-lived woody tissues, exposure to elevated CO2 caused a large increase in the production of labile fine roots in the sweetgum forest. Greater allocation to more labile tissues may cause more rapid cycling of C back to the atmosphere in the sweetgum forest compared to the pine forest. Imbalances in the N cycle may reduce the response of these forests to experimental exposure to elevated CO2 in the future, but even at the current stimulation observed for these forests, the effect of changes in land use on C sequestration are likely to be larger than the effect of CO2-induced growth stimulation.

  10. Wildfire effects on biological properties of soils in forest-steppe ecosystems of Russia

    NASA Astrophysics Data System (ADS)

    Maksimova, Ekaterina; Abakumov, Evgeny

    2013-04-01

    Forest fires are regularly repeating natural phenomenon that disturb natural balance between separate components of ecosystems and influence on the type of vegetation and dynamics of plant communities. The soil, as a basic component of forest ecosystems, is affected by different impacts of wildfires. Independently of a type and intensity of a fire the plant cover and a upper soil horizon always burn. There is also a transformation of the top organo-mineral and mineral horizons of soils when it's strong influence of fire and full combustion of a laying. Complicated fire conditions in summer of 2010 were caused by extreme climatic effects and low precipitations. The area of soils affected by wildfires assessed as more than 744 000 ha. Forest fires have occupied Moscow, Yekaterinburg, Kaluga, Pskov, Samara and many other regions. The critical situation in the Samarskaya region around Togliatti city results in huge soil dergradation in forest-steppe pine forests. The analytical data obtained shows that wildfires lead to serious changes in a soil profile. The most intensive were the processes of humus losses that result from burning of a forest floor and sod (humic) horizon. Wildfires change a chemical composition of laying and raise their ash-content. Fires lead to increase of biogenic elements' content in the upper horizon - P and K. The content of phosphorus and potassium in 2011 decreased as a result of carrying out with an atmospheric precipitation. Thus, when it is burning the top horizons the ashes arriving on a surface of the soil enrich it with nutrients. Moreover, there is an increase of the calcium content. Calcium provides alkaline reaction of the top horizons. But the next year the content of calcium in upper soil horizons decreased. The soil unaffected by fire is characterized by the greatest content of soil microbial biomass in the top horizon and, respectively, the bigger index of bazal respiration whereas a reduction of both parameters is noted on

  11. Untangling positive and negative biotic interactions: views from above and below ground in a forest ecosystem.

    PubMed

    Montgomery, Rebecca A; Reich, Peter B; Palik, Brian J

    2010-12-01

    In ecological communities, the outcome of plant-plant interactions represents the net effect of positive and negative interactions occurring above and below ground. Untangling these complex relationships can provide a better understanding of mechanisms that underlie plant-plant interactions and enhance our ability to predict population, community, and ecosystem effects of biotic interactions. In forested ecosystems, tree seedlings interact with established vegetation, but the mechanisms and outcomes of these interactions are not well understood. To explore such mechanisms, we manipulated above- and belowground interactions among tree seedlings, shrubs, and trees and monitored seedling survival and growth of six species (Pinus banksiana, Betula papyrifera, P. resinosa, Quercus rubra, P. strobus, and Acer rubrum) in mature pine-dominated forest in northern Minnesota, USA. The forest had a moderately open canopy and sandy soils. Understory manipulations were implemented in the forest interior and in large gaps and included removal of shrubs (no interactions), tieback of shrubs (belowground), removal of shrubs with addition of shade (aboveground), and unmanipulated shrubs (both below- and aboveground). We found that shrubs either suppressed or facilitated seedling survival and growth depending on the seedling species, source of interaction (e.g., above- or belowground), and ecological context (e.g., gap or forest interior). In general, shrubs strongly influenced survival and growth in gaps, with more modest effects in the forest interior. In gaps, the presence of shrub roots markedly decreased seedling growth and survival, supporting the idea that belowground competition may be more important in dry, nutrient-poor sites. Shrub shade effects were neutral for three species and facilitative for the other three. Facilitation was more likely for shade-tolerant species. In the forest interior, shrub shade negatively affected seedling survival for the most shade

  12. Chemosynthetic ecosystems study. Final report. Volume 1. Executive summary

    SciTech Connect

    MacDonald, I.R.; Sager, W.W.; Lee, C.; Schroeder, W.W.; Kennicutt, M.C.

    1995-06-01

    Volume I presents a brief summary of the findings of a three year investigation of the geology, chemistry, and biology of chemosynthetic ecosystems in the Gulf of Mexico. These dense assemblages of tube worms, mussels and/or clams are primarily dependent upon chemical conditions generated by natural oils and gas seeps. Hydrocarbon seeps produce a variety of distinctive geological features including carbonate rock, mud volcanoes, and hydrate mounds, which tend to be localized to areas less than 1 km. The interaction of the sediment bacteria with the hydrocarbons in the seafloor yields a highly specialized chemical environment featuring high levels of hydrogen sulfide and degraded oils.

  13. Ecosystem Carbon Stock Influenced by Plantation Practice: Implications for Planting Forests as a Measure of Climate Change Mitigation

    PubMed Central

    Liao, Chengzhang; Luo, Yiqi; Fang, Changming; Li, Bo

    2010-01-01

    Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha−1 in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age (<25 years vs. ≥25 years), stand types (broadleaved vs. coniferous and deciduous vs. evergreen), tree species origin (native vs. exotic) of plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation. PMID:20523733

  14. Ecosystem carbon stock influenced by plantation practice: implications for planting forests as a measure of climate change mitigation.

    PubMed

    Liao, Chengzhang; Luo, Yiqi; Fang, Changming; Li, Bo

    2010-01-01

    Uncertainties remain in the potential of forest plantations to sequestrate carbon (C). We synthesized 86 experimental studies with paired-site design, using a meta-analysis approach, to quantify the differences in ecosystem C pools between plantations and their corresponding adjacent primary and secondary forests (natural forests). Totaled ecosystem C stock in plant and soil pools was 284 Mg C ha(-1) in natural forests and decreased by 28% in plantations. In comparison with natural forests, plantations decreased aboveground net primary production, litterfall, and rate of soil respiration by 11, 34, and 32%, respectively. Fine root biomass, soil C concentration, and soil microbial C concentration decreased respectively by 66, 32, and 29% in plantations relative to natural forests. Soil available N, P and K concentrations were lower by 22, 20 and 26%, respectively, in plantations than in natural forests. The general pattern of decreased ecosystem C pools did not change between two different groups in relation to various factors: stand age (< 25 years vs. > or = 25 years), stand types (broadleaved vs. coniferous and deciduous vs. evergreen), tree species origin (native vs. exotic) of plantations, land-use history (afforestation vs. reforestation) and site preparation for plantations (unburnt vs. burnt), and study regions (tropic vs. temperate). The pattern also held true across geographic regions. Our findings argued against the replacement of natural forests by the plantations as a measure of climate change mitigation.

  15. A Statistical Methodology for Detecting and Monitoring Change in Forest Ecosystems Using Remotely Sensed Imagery

    NASA Astrophysics Data System (ADS)

    Mills, R. T.; Kumar, J.; Hoffman, F. M.; Hargrove, W. W.; Spruce, J.

    2011-12-01

    Variations in vegetation phenology, the annual temporal pattern of leaf growth and senescence, can be a strong indicator of ecological change or disturbance. However, phenology is also strongly influenced by seasonal, interannual, and long-term trends in climate, making identification of changes in forest ecosystems a challenge. Forest ecosystems are vulnerable to extreme weather events, insect and disease attacks, wildfire, harvesting, and other land use change. Normalized difference vegetation index (NDVI), a remotely sensed measure of greenness, provides a proxy for phenology. NDVI for the conterminous United States (CONUS) derived from the Moderate Resolution Spectroradiometer (MODIS) at 250 m resolution was used in this study to develop phenological signatures of ecological regimes called phenoregions. By applying a quantitative data mining technique to the NDVI measurements for every eight days over the entire MODIS record, annual maps of phenoregions were developed. This geospatiotemporal cluster analysis technique employs high performance computing resources, enabling analysis of such very large data sets. This technique produces a prescribed number of prototypical phenological states to which every location belongs in any year. Analysis of the shifts among phenological states yields information about responses to interannual climate variability and, more importantly, changes in ecosystem health due to disturbances. Moreover, a large change in the phenological states occupied by a single location over time indicates a significant disturbance or ecological shift. This methodology has been applied for identification of various forest disturbance events, including wildfire, tree mortality due to Mountain Pine Beetle, and other insect infestation and diseases, as well as extreme events like storms and hurricanes in the U.S. Presented will be results from analysis of phenological state dynamics, along with disturbance and validation data.

  16. Influence of physiological phenology on the seasonal pattern of ecosystem respiration in deciduous forests.

    PubMed

    Migliavacca, Mirco; Reichstein, Markus; Richardson, Andrew D; Mahecha, Miguel D; Cremonese, Edoardo; Delpierre, Nicolas; Galvagno, Marta; Law, Beverly E; Wohlfahrt, Georg; Black, T Andrew; Carvalhais, Nuno; Ceccherini, Guido; Chen, Jiquan; Gobron, Nadine; Koffi, Ernest; Munger, J William; Perez-Priego, Oscar; Robustelli, Monica; Tomelleri, Enrico; Cescatti, Alessandro

    2015-01-01

    Understanding the environmental and biotic drivers of respiration at the ecosystem level is a prerequisite to further improve scenarios of the global carbon cycle. In this study we investigated the relevance of physiological phenology, defined as seasonal changes in plant physiological properties, for explaining the temporal dynamics of ecosystem respiration (RECO) in deciduous forests. Previous studies showed that empirical RECO models can be substantially improved by considering the biotic dependency of RECO on the short-term productivity (e.g., daily gross primary production, GPP) in addition to the well-known environmental controls of temperature and water availability. Here, we use a model-data integration approach to investigate the added value of physiological phenology, represented by the first temporal derivative of GPP, or alternatively of the fraction of absorbed photosynthetically active radiation, for modeling RECO at 19 deciduous broadleaved forests in the FLUXNET La Thuile database. The new data-oriented semiempirical model leads to an 8% decrease in root mean square error (RMSE) and a 6% increase in the modeling efficiency (EF) of modeled RECO when compared to a version of the model that does not consider the physiological phenology. The reduction of the model-observation bias occurred mainly at the monthly time scale, and in spring and summer, while a smaller reduction was observed at the annual time scale. The proposed approach did not improve the model performance at several sites, and we identified as potential causes the plant canopy heterogeneity and the use of air temperature as a driver of ecosystem respiration instead of soil temperature. However, in the majority of sites the model-error remained unchanged regardless of the driving temperature. Overall, our results point toward the potential for improving current approaches for modeling RECO in deciduous forests by including the phenological cycle of the canopy. PMID:24990223

  17. Long-term increase in forest water-use efficiency observed across ecosystem carbon flux networks

    NASA Astrophysics Data System (ADS)

    Keenan, Trevor; Bohrer, Gil; Dragoni, Danilo; Hollinger, David; Munger, James W.; Schmid, Hans Peter; Richardson, Andrew

    2014-05-01

    Terrestrial plants remove CO2 from the atmosphere through photo- synthesis, a process that is accompanied by the loss of water vapour from leaves. The ratio of water loss to carbon gain, or water-use efficiency, is a key characteristic of ecosystem function that is central to the global cycles of water, energy and carbon. Here we analyse direct, long-term measurements of whole-ecosystem carbon and water exchange. We find a substantial increase in water-use efficiency in temperate and boreal forests of the Northern Hemisphere over the past two decades. We systematically assess various competing hypotheses to explain this trend, and find that the observed increase is most consistent with a strong CO2 fertilization effect. The results suggest a partial closure of stomata - small pores on the leaf surface that regulate gas exchange - to maintain a near- constant concentration of CO2 inside the leaf even under continually increasing atmospheric CO2 levels. The observed increase in forest water-use efficiency is larger than that predicted by existing theory and 13 terrestrial biosphere models. The increase is associated with trends of increasing ecosystem-level photosynthesis and net carbon uptake, and decreasing evapotranspiration. Our findings demonstrate the utility of maintaining long-term eddy-covariance flux measurement sites. The results suggest a shift in the carbon- and water-based economics of terrestrial vegetation, which may require a reassessment of the role of stomatal control in regulating interactions between forests and climate change, and a re-evaluation of coupled vegetation-climate models.

  18. Influence of physiological phenology on the seasonal pattern of ecosystem respiration in deciduous forests.

    PubMed

    Migliavacca, Mirco; Reichstein, Markus; Richardson, Andrew D; Mahecha, Miguel D; Cremonese, Edoardo; Delpierre, Nicolas; Galvagno, Marta; Law, Beverly E; Wohlfahrt, Georg; Black, T Andrew; Carvalhais, Nuno; Ceccherini, Guido; Chen, Jiquan; Gobron, Nadine; Koffi, Ernest; Munger, J William; Perez-Priego, Oscar; Robustelli, Monica; Tomelleri, Enrico; Cescatti, Alessandro

    2015-01-01

    Understanding the environmental and biotic drivers of respiration at the ecosystem level is a prerequisite to further improve scenarios of the global carbon cycle. In this study we investigated the relevance of physiological phenology, defined as seasonal changes in plant physiological properties, for explaining the temporal dynamics of ecosystem respiration (RECO) in deciduous forests. Previous studies showed that empirical RECO models can be substantially improved by considering the biotic dependency of RECO on the short-term productivity (e.g., daily gross primary production, GPP) in addition to the well-known environmental controls of temperature and water availability. Here, we use a model-data integration approach to investigate the added value of physiological phenology, represented by the first temporal derivative of GPP, or alternatively of the fraction of absorbed photosynthetically active radiation, for modeling RECO at 19 deciduous broadleaved forests in the FLUXNET La Thuile database. The new data-oriented semiempirical model leads to an 8% decrease in root mean square error (RMSE) and a 6% increase in the modeling efficiency (EF) of modeled RECO when compared to a version of the model that does not consider the physiological phenology. The reduction of the model-observation bias occurred mainly at the monthly time scale, and in spring and summer, while a smaller reduction was observed at the annual time scale. The proposed approach did not improve the model performance at several sites, and we identified as potential causes the plant canopy heterogeneity and the use of air temperature as a driver of ecosystem respiration instead of soil temperature. However, in the majority of sites the model-error remained unchanged regardless of the driving temperature. Overall, our results point toward the potential for improving current approaches for modeling RECO in deciduous forests by including the phenological cycle of the canopy.

  19. Ophiocordyceps unilateralis: A keystone species for unraveling ecosystem functioning and biodiversity of fungi in tropical forests?

    PubMed

    Evans, Harry C; Elliot, Simon L; Hughes, David P

    2011-09-01

    Ophiocordyceps unilateralis (Ascomycota: Hypocreales) is a specialized parasite that infects, manipulates and kills formicine ants, predominantly in tropical forest ecosystems. We have reported previously, based on a preliminary study in remnant Atlantic Forest in Minas Gerais (Brazil), that O. unilateralis represents a species complex. On each of the four species of infected carpenter ant (Camponotus) collected, the fungus-characterized macroscopically by a single stalk arising from the dorsal neck region on which the sexual structures (stromatal plates) are borne laterally-can readily be distinguished both microscopically and functionally. Here, we describe and discuss the biology, life cycle and infection strategies of O. unilateralis s.l. and hypothesize that there may be hundreds of species within the complex parasitizing formicine ants worldwide. We then address the diversity within related hypocrealean fungi, with particular reference to symbionts (mutualists through to parasites), and argue that the widely-quoted total of extant fungi (1.5 million species) may be grossly underestimated.

  20. Predicting mosaics and wildlife diversity resulting from fire disturbance to a forest ecosystem

    NASA Astrophysics Data System (ADS)

    Potter, Meredith W.; Kessell, Stephen R.

    1980-05-01

    A model for predicting community mosaics and wildlife diversity resulting from fire disturbance to a forest ecosystem is presented. It applies an algorithm that delineates the size and shape of each patch from grid-based input data and calculates standard diversity measures for the entire mosaic of community patches and their included animal species. The user can print these diversity calculations, maps of the current community-type-age-class mosaic, and maps of habitat utilization by each animal species. Furthermore, the user can print estimates of changes in each resulting from natural disturbance. Although data and resolution level independent, the model is demonstrated and tested with data from the Lewis and Clark National Forest in Montana.

  1. Evaluation of approaches to calculate critical metal loads for forest ecosystems.

    PubMed

    de Vries, W; Groenenberg, J E

    2009-12-01

    This paper evaluates approaches to calculate acceptable loads for metal deposition to forest ecosystems, distinguishing between critical loads, stand-still loads and target loads. We also evaluated the influence of including the biochemical metal cycle on the calculated loads. Differences are illustrated by examples of Cd, Cu, Pb and Zn for a deciduous forest on five major soil types in the Netherlands. Stand-still loads are generally lower than critical loads, which in turn are lower than the target loads indicating that present levels are below critical levels. Uncertainties in the calculated critical loads are mainly determined by the uncertainty in the critical limits and the chemical speciation model. Including the metal cycle has a small effect on the calculated critical loads. Results are discussed in view of the applicability of the critical load concept for metals in future protocols on the reduction in metal emissions.

  2. Effects of Forest Age on Soil Fungal Community in a Northern Temperate Ecosystem.

    PubMed

    Zhiguang, Han; Xin, Sui; Mengsha, Li

    2016-09-01

    The polymorphisms of soil fungal rDNA Internal Transcribed Spacer regions were studied in Korean pine forests of various ages (10-100-year-old trees) by means of cloned libraries, and analyzed to determine the effects of the trees' developmental stage on soil fungal community structure. The obtained Shannon diversity index (H) and richness (S) indicated that the diversity of the soil fungal community increased significantly with the development of Korean pines (P < 0.05). In addition, cluster analysis (UPGMA) showed that the soil fungal community variety associated with differently aged Korean pines was higher than 50 %. The soil fungal community diversity correlated significantly with the N content and C/N ratio of the soil (P < 0.05). The results of this study indicate that the age of in Korean pine can affect soil fungal community by altering soil properties, which in turn could affect the nutrient cycling in the forest ecosystem.

  3. Simulated effects of temperature and precipitation change in several forest ecosystems

    NASA Astrophysics Data System (ADS)

    Johnson, D. W.; Susfalk, R. B.; Gholz, H. L.; Hanson, P. J.

    2000-08-01

    The Nutrient Cycling Model (NuCM) was used to investigate the effects of increased temperature (+4°C) and changing precipitation (increased and decreased) on biogeochemical cycling at six forest sites in the United States: a Picea rubens forest at Nolan Divide in the Great Smoky Mountains, North Carolina; mixed deciduous forests at Walker Branch, Tennessee and Coweeta, North Carolina; a Pinus taeda forest at Duke, North Carolina; a P. eliottii forest at Bradford, Florida; and a P. contorta/P. jeffreyii forest at Little Valley, Nevada. Simulations of increased temperature indicated increased evapotranspiration and reduced water flux. Simulations of changes in precipitation indicated disproportionately large variations in soil water flux because of the relative stability of evapotranspiration with changes in precipitation. Increased temperature caused N release from forest floors at all sites. At the N-saturated Nolan Divide site, this resulted in no change in N uptake or growth but increased soil solution Al and NO 3- and increased N leaching losses. At the N-limited sites, the release of N from the forest floor caused increased growth, and, in some cases, increased NO 3- leaching as well, indicating that N released from the forest floor was not efficiently taken up by the vegetation. Increased precipitation caused increased growth, and decreased precipitation caused reduced growth in the N-limited sites because of changes in wet N deposition. Changes in precipitation had no effect on growth in the N-saturated Nolan Divide site, but did cause large changes in soil solution mineral acid anion and Al concentrations. Increased precipitation caused long-term decreases in soil exchangeable base cations in most cases because of the disproportionately large effects on soil water flux; however, increased precipitation caused decreases in exchangeable base cations in cases where atmospheric deposition was a major source of base cations for the system. The simulation results

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

    PubMed

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

    2014-08-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2 ) and tropospheric ozone (O3 ) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3 . Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r(2) = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m(-2) ) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (∆NPP/∆N) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2 . Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content.

  5. Progressive nitrogen limitation of ecosystem processes under elevated CO2 in a warm-temperate forest.

    PubMed

    Finzi, Adrien C; Moore, David J P; DeLucia, Evan H; Lichter, John; Hofmockel, Kirsten S; Jackson, Robert B; Kim, Hyun-Seok; Matamala, Roser; McCarthy, Heather R; Oren, Ram; Pippen, Jeffrey S; Schlesinger, William H

    2006-01-01

    A hypothesis for progressive nitrogen limitation (PNL) proposes that net primary production (NPP) will decline through time in ecosystems subjected to a step-function increase in atmospheric CO2. The primary mechanism driving this response is a rapid rate of N immobilization by plants and microbes under elevated CO2 that depletes soils of N, causing slower rates of N mineralization. Under this hypothesis, there is little long-term stimulation of NPP by elevated CO2 in the absence of exogenous inputs of N. We tested this hypothesis using data on the pools and fluxes of C and N in tree biomass, microbes, and soils from 1997 through 2002 collected at the Duke Forest free-air CO2 enrichment (FACE) experiment. Elevated CO2 stimulated NPP by 18-24% during the first six years of this experiment. Consistent with the hypothesis for PNL, significantly more N was immobilized in tree biomass and in the O horizon under elevated CO2. In contrast to the PNL hypothesis, microbial-N immobilization did not increase under elevated CO2, and although the rate of net N mineralization declined through time, the decline was not significantly more rapid under elevated CO2. Ecosystem C-to-N ratios widened more rapidly under elevated CO2 than ambient CO2 indicating a more rapid rate of C fixation per unit of N, a processes that could delay PNL in this ecosystem. Mass balance calculations demonstrated a large accrual of ecosystem N capital. Is PNL occurring in this ecosystem and will NPP decline to levels under ambient CO2? The answer depends on the relative strength of tree biomass and O-horizon N immobilization vs. widening C-to-N ratios and ecosystem-N accrual as processes that drive and delay PNL, respectively. Only direct observations through time will definitively answer this question.

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

    PubMed

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

    2014-08-01

    Three young northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2 ) and tropospheric ozone (O3 ) for 11 years. Here, we report results from an extensive sampling of plant biomass and soil conducted at the conclusion of the experiment that enabled us to estimate ecosystem carbon (C) content and cumulative net primary productivity (NPP). Elevated CO2 enhanced ecosystem C content by 11%, whereas elevated O3 decreased ecosystem C content by 9%. There was little variation in treatment effects on C content across communities and no meaningful interactions between CO2 and O3 . Treatment effects on ecosystem C content resulted primarily from changes in the near-surface mineral soil and tree C, particularly differences in woody tissues. Excluding the mineral soil, cumulative NPP was a strong predictor of ecosystem C content (r(2) = 0.96). Elevated CO2 enhanced cumulative NPP by 39%, a consequence of a 28% increase in canopy nitrogen (N) content (g N m(-2) ) and a 28% increase in N productivity (NPP/canopy N). In contrast, elevated O3 lowered NPP by 10% because of a 21% decrease in canopy N, but did not impact N productivity. Consequently, as the marginal impact of canopy N on NPP (∆NPP/∆N) decreased through time with further canopy development, the O3 effect on NPP dissipated. Within the mineral soil, there was less C in the top 0.1 m of soil under elevated O3 and less soil C from 0.1 to 0.2 m in depth under elevated CO2 . Overall, these results suggest that elevated CO2 may create a sustained increase in NPP, whereas the long-term effect of elevated O3 on NPP will be smaller than expected. However, changes in soil C are not well-understood and limit our ability to predict changes in ecosystem C content. PMID:24604779

  7. High-Resolution Forest Canopy Height Estimation in an African Blue Carbon Ecosystem

    NASA Technical Reports Server (NTRS)

    Lagomasino, David; Fatoyinbo, Temilola; Lee, Seung-Kuk; Simard, Marc

    2015-01-01

    Mangrove forests are one of the most productive and carbon dense ecosystems that are only found at tidally inundated coastal areas. Forest canopy height is an important measure for modeling carbon and biomass dynamics, as well as land cover change. By taking advantage of the flat terrain and dense canopy cover, the present study derived digital surface models (DSMs) using stereophotogrammetric techniques on high-resolution spaceborne imagery (HRSI) for southern Mozambique. A mean-weighted ground surface elevation factor was subtracted from the HRSI DSM to accurately estimate the canopy height in mangrove forests in southern Mozambique. The mean and H100 tree height measured in both the field and with the digital canopy model provided the most accurate results with a vertical error of 1.18-1.84 m, respectively. Distinct patterns were identified in the HRSI canopy height map that could not be discerned from coarse shuttle radar topography mission canopy maps even though the mode and distribution of canopy heights were similar over the same area. Through further investigation, HRSI DSMs have the potential of providing a new type of three-dimensional dataset that could serve as calibration/validation data for other DSMs generated from spaceborne datasets with much larger global coverage. HSRI DSMs could be used in lieu of Lidar acquisitions for canopy height and forest biomass estimation, and be combined with passive optical data to improve land cover classifications.

  8. [Evaluation of ecosystem service values of the forests of Shennongjia Nature Reserve].

    PubMed

    Liu, Yong-Jie; Wang, Shi-Chang; Peng, Hao; Li, Zhen-Qing

    2014-05-01

    As an ecological protected area for rare animals and plants in a subtropical forest zone, Shennongjia National Reserve plays an important role in the study of biodiversity in China. By using the market value, shade-price and opportunity-cost methods, the forest ecosystem service values of Shennongjia National Nature Reserve were evaluated, including forest production, recreation and culture, water conservation, soil conservation, gas regulation, environment purification, nutrient circulation and biodiversity conservation. The total value of the Shennongjia Nature Reserve was approximately 204.33 x 10(8) yuan RMB x a(-1). The values of the different functions were in order of biodiversity conservation (68.5%) > soil conservation (12.7%) > recreation and culture (4.9%) > gas regulation (4.8%) > forest production (4.2%) > water conservation (3.9%) > environment purification (0.7%) > nutrient circulation (0.3%). The values with respect to utility were in sequence of unused value (68.5%) > indirect value in use (22.4% ) > direct value in use (9.1%).

  9. Earthworms as ecosystem engineers and the most important detritivors in forest soils.

    PubMed

    Kooch, Yahya; Jalilvand, Hamid

    2008-03-15

    Earthworms are considered as soil engineers because of their effects on soil properties and their influence on the availability of resources for other organisms, including microorganisms and plants. However, the links between their impacts on the soil environment and the resulting modification of natural selection pressures on engineer as well as on other organisms have received little attention. Earthworms are known to have a positive influence on the soil fabric and on the decomposition and mineralization of litter by breaking down organic matter and producing large amounts of fasces, thereby mixing litter with the mineral soil. Therefore, they play an important part in changes from one humus from to another according to forest succession patterns. Consequently, they are also expected to be good bio-indicators for forest site quality and are thus useful when planning forest production improvement. Earthworm's populations are as indicator that in exploited regions is destruction indicator and reclamation plans is nature return indicator. In this study we summarized the current knowledge in relation to earthworm's ecology in forest soils as ecosystem engineers. PMID:18814642

  10. Changes on albedo after a large forest fire in Mediterranean ecosystems

    NASA Astrophysics Data System (ADS)

    Quintano, Carmen; Fernández-Manso, Alfonso; Fernández-García, Victor; Marcos, Elena; Calvo, Leonor

    2015-09-01

    Fires are one of the main causes of environmental alteration in Mediterranean forest ecosystems. Albedo varies and evolves seasonally based on solar illumination. It is greatly influenced by changes on vegetation: vegetation growth, cutting/planting forests or forest fires. This work analyzes albedo variations due to a large forest fire that occurred on 19- 21 September 2012 in northwestern Spain. From this area, albedo post-fire images (immediately and 1-year after fire) were generated from Landsat 7 Enhanced Thematic Mapper (ETM+) data. Specifically we considered total shortwave albedo, total-, direct-, and diffuse-visible, and near-infrared albedo. Nine to twelve weeks after fire, 111 field plots were measured (27 unburned plots, 84 burned plots). The relationship between albedo values and thematic class (burned/unburned) was evaluated by one-way analysis of variance. Our results demonstrate that albedo changes were related to burned/unburned variable with statistical significance, indicating the importance of forestry areas as regulators of land surface energy fluxes and revealing the potential of post-fire albedo for assessing burned areas. Future research, however, is needed to evaluate the persistence of albedo changes.

  11. Jack-of-all-trades effects drive biodiversity-ecosystem multifunctionality relationships in European forests.

    PubMed

    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

    2016-03-24

    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.

  12. Jack-of-all-trades effects drive biodiversity-ecosystem multifunctionality relationships in European forests.

    PubMed

    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

  13. Jack-of-all-trades effects drive biodiversity–ecosystem multifunctionality relationships in European forests

    PubMed Central

    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

  14. Reconstructing the Mexican Tropical Dry Forests via an Autoecological Niche Approach: Reconsidering the Ecosystem Boundaries.

    PubMed

    Prieto-Torres, David A; Rojas-Soto, Octavio R

    2016-01-01

    We used Ecological Niche Modeling (ENM) of individual species of two taxonomic groups (plants and birds) in order to reconstruct the climatic distribution of Tropical Dry Forests (TDFs) in Mexico and to analyze their boundaries with other terrestrial ecosystems. The reconstruction for TDFs' distribution was analyzed considering the prediction and omission errors based upon the combination of species, obtained from the overlap of individual models (only plants, only birds, and all species combined). Two verifications were used: a primary vegetation map and 100 independent TDFs localities. We performed a Principal Component (PCA) and Discriminant Analysis (DA) to evaluate the variation in the environmental variables and ecological overlap among ecosystems. The modeling strategies showed differences in the ecological patterns and prediction areas, where the "all species combined" model (with a threshold of ≥10 species) was the best strategy to use in the TDFs reconstruction. We observed a concordance of 78% with the primary vegetation map and a prediction of 98% of independent locality records. Although PCA and DA tests explained 75.78% and 97.9% of variance observed, respectively, we observed an important overlap among the TDFs with other adjacent ecosystems, confirming the existence of transition zones among them. We successfully modeled the distribution of Mexican TDFs using a number of bioclimatic variables and co-distributed species. This autoecological niche approach suggests the necessity of rethinking the delimitations of ecosystems based on the recognition of transition zones among them in order to understand the real nature of communities and association patterns of species.

  15. Ozone deposition in a mixed forest ecosystem - temporal variation and removal processes

    NASA Astrophysics Data System (ADS)

    Pokorska, Olga; Gruening, Carsten; Goded, Ignacio

    2016-04-01

    Forests are a major sink for tropospheric ozone, however the fate of ozone within the forest canopy is still not well understood. In this study we will present results of 3 years ozone flux measurements at eddy covariance flux tower in Ispra (Northern Italy) over mixed forest ecosystem. The main tree species in this ecosystem are Quercus robur (80%), Alnus glutinosa (10%), Populus alba (5%) and Carpinus betulus (3%). The measurements were carried out continuously from January 2013 till December 2015. Flux measurements at the canopy level with the eddy covariance technique were complemented with measurements of meteorological parameters and measurements of VOCs (Volatile Organic Compounds) using PTR-MS (Proton Transfer Reaction - Mass Spectrometry) during an intensive observation period. Continuous measurements produced a big dataset which allowed us to investigate the controls on ozone fluxes and to do multiyear comparisons. Patterns of ozone concentration, ozone fluxes and ozone deposition velocity over forest canopy will be presented in relation to physiological activity of the trees and time of the year. Current research is mainly aimed at better understanding of the contribution of destruction processes within the canopy. Therefore, the collected data were used to calculate the partitioning of total ozone fluxes between stomatal and non-stomatal sinks. We found that the stomatal uptake contributed less that non-stomatal uptake to the total ozone flux during the growing seasons. In particular, non-stomatal ozone removal by reactions with isoprene and other VOCs will be discussed. We will present contribution and change of individual ozone deposition sinks over the years in response to environmental parameters.

  16. Endurance of larch forest ecosystems in eastern Siberia under warming trends.

    PubMed

    Sato, Hisashi; Kobayashi, Hideki; Iwahana, Go; Ohta, Takeshi

    2016-08-01

    The larch (Larix spp.) forest in eastern Siberia is the world's largest coniferous forest. Its persistence is considered to depend on near-surface permafrost, and thus, forecast warming over the 21st century and consequent degradation of near-surface permafrost is expected to affect the larch forest in Siberia. However, predictions of these effects vary greatly, and many uncertainties remain about land - atmosphere interactions within the ecosystem. We developed an integrated land surface model to analyze how the Siberian larch forest will react to current warming trends. This model analyzed interactions between vegetation dynamics and thermo-hydrology, although it does not consider many processes those are considered to affect productivity response to a changing climate (e.g., nitrogen limitation, waterlogged soil, heat stress, and change in species composition). The model showed that, under climatic conditions predicted under gradual and rapid warming, the annual net primary production of larch increased about 2 and 3 times, respectively, by the end of the 21st century compared with that in the previous century. Soil water content during the larch-growing season showed no obvious trend, even when surface permafrost was allowed to decay and result in subsurface runoff. A sensitivity test showed that the forecast temperature and precipitation trends extended larch leafing days and reduced water shortages during the growing season, thereby increasing productivity. The integrated model also satisfactorily reconstructed latitudinal gradients in permafrost presence, soil moisture, tree leaf area index, and biomass over the entire larch-dominated area in eastern Siberia. Projected changes to ecosystem hydrology and larch productivity at this geographical scale were consistent with those from site-level simulation. This study reduces the uncertainty surrounding the impact of current climate trends on this globally important carbon reservoir, and it demonstrates the need

  17. Dust and canopy effects on snowpack melt and ecosystem processes in a subalpine forest

    NASA Astrophysics Data System (ADS)

    Maurer, G. E.; Bowling, D. R.

    2013-12-01

    Dust deposition lowers the albedo of mountain snowpacks and can significantly impact the rate of spring snowpack melt. Recent research has shown that aeolian dust deposition may significantly advance the timing of snowmelt and spring runoff in the hydrologic basins of the western U.S. These studies have focused on alpine and subalpine snowpacks with little to no overstory vegetation cover. We conducted a manipulative experiment to assess the impacts of dust deposition on snowpack melt and ecosystem processes in a subalpine conifer forest. From mid-March to the snow all gone date in 2010-2012, we scattered dust in forested plots at weekly to bi-weekly frequency. This roughly doubled the ambient dust loading at the site. In control and dust-addition treatments we measured the springtime decline in snow water equivalent, continuous soil temperature and moisture, and litter mass loss (decomposition) and soil respiration below the snowpack and during the warm season. Xylem water potential in conifers was also measured during the warm season. We found that the effect of dust deposition on the melt rate was dependent on the openness of the canopy within our forest, as were differences in the timing and magnitude of soil moisture changes. Ecosystem processes were similar in dust-addition and control plots and were responsive to soil temperature and moisture variations below the snowpack and during the warm season. From this we conclude that the effect of aeolian dust deposition on snowpack energy balance, and associated ecohydrological processes, varies with canopy structure in subalpine forests.

  18. Modelling the ecological vulnerability to forest fires in mediterranean ecosystems using geographic information technologies.

    PubMed

    Duguy, Beatriz; Alloza, José Antonio; Baeza, M Jaime; De la Riva, Juan; Echeverría, Maite; Ibarra, Paloma; Llovet, Juan; Cabello, Fernando Pérez; Rovira, Pere; Vallejo, Ramon V

    2012-12-01

    Forest fires represent a major driver of change at the ecosystem and landscape levels in the Mediterranean region. Environmental features and vegetation are key factors to estimate the ecological vulnerability to fire; defined as the degree to which an ecosystem is susceptible to, and unable to cope with, adverse effects of fire (provided a fire occurs). Given the predicted climatic changes for the region, it is urgent to validate spatially explicit tools for assessing this vulnerability in order to support the design of new fire prevention and restoration strategies. This work presents an innovative GIS-based modelling approach to evaluate the ecological vulnerability to fire of an ecosystem, considering its main components (soil and vegetation) and different time scales. The evaluation was structured in three stages: short-term (focussed on soil degradation risk), medium-term (focussed on changes in vegetation), and coupling of the short- and medium-term vulnerabilities. The model was implemented in two regions: Aragón (inland North-eastern Spain) and Valencia (eastern Spain). Maps of the ecological vulnerability to fire were produced at a regional scale. We partially validated the model in a study site combining two complementary approaches that focused on testing the adequacy of model's predictions in three ecosystems, all very common in fire-prone landscapes of eastern Spain: two shrublands and a pine forest. Both approaches were based on the comparison of model's predictions with values of NDVI (Normalized Difference Vegetation Index), which is considered a good proxy for green biomass. Both methods showed that the model's performance is satisfactory when applied to the three selected vegetation types.

  19. Modelling and predicting the spatial distribution of tree root density in heterogeneous forest ecosystems

    PubMed Central

    Mao, Zhun; Saint-André, Laurent; Bourrier, Franck; Stokes, Alexia; Cordonnier, Thomas

    2015-01-01

    Background and Aims In mountain ecosystems, predicting root density in three dimensions (3-D) is highly challenging due to the spatial heterogeneity of forest communities. This study presents a simple and semi-mechanistic model, named ChaMRoots, that predicts root interception density (RID, number of roots m–2). ChaMRoots hypothesizes that RID at a given point is affected by the presence of roots from surrounding trees forming a polygon shape. Methods The model comprises three sub-models for predicting: (1) the spatial heterogeneity – RID of the finest roots in the top soil layer as a function of tree basal area at breast height, and the distance between the tree and a given point; (2) the diameter spectrum – the distribution of RID as a function of root diameter up to 50 mm thick; and (3) the vertical profile – the distribution of RID as a function of soil depth. The RID data used for fitting in the model were measured in two uneven-aged mountain forest ecosystems in the French Alps. These sites differ in tree density and species composition. Key Results In general, the validation of each sub-model indicated that all sub-models of ChaMRoots had good fits. The model achieved a highly satisfactory compromise between the number of aerial input parameters and the fit to the observed data. Conclusions The semi-mechanistic ChaMRoots model focuses on the spatial distribution of root density at the tree cluster scale, in contrast to the majority of published root models, which function at the level of the individual. Based on easy-to-measure characteristics, simple forest inventory protocols and three sub-models, it achieves a good compromise between the complexity of the case study area and that of the global model structure. ChaMRoots can be easily coupled with spatially explicit individual-based forest dynamics models and thus provides a highly transferable approach for modelling 3-D root spatial distribution in complex forest ecosystems. PMID:26173892

  20. Application of ecosystem model and Markov Chain Monte Carlo method for parameter optimization and ecosystem productivity prediction at seven forest flux sites across North America

    NASA Astrophysics Data System (ADS)

    Peng, C.; Zhou, X.

    2015-12-01

    To reduce simulation uncertainties due to inaccurate model parameters, the Markov Chain Monte Carlo (MCMC) method was applied in this study to improve the estimations of four key parameters used in the process-based ecosystem model of TRIPLEX-FLUX. These four key parameters include a maximum photosynthetic carboxylation rate of 25°C (Vcmax), an electron transport (Jmax) light-saturated rate within the photosynthetic carbon reduction cycle of leaves, a coefficient of stomatal conductance (m), and a reference respiration rate of 10ºC (R10). Seven forest flux tower sites located across North America were used to investigate and facilitate understanding of the daily variation in model parameters for three deciduous forests, three evergreen temperate forests, and one evergreen boreal forest. Eddy covariance CO2 exchange measurements were assimilated to optimize the parameters in the year 2006. After parameter optimization and adjustment took place, net ecosystem production prediction significantly improved (by approximately 25%) compared to the CO2 flux measurements taken at the seven forest ecosystem sites.

  1. Impacts of shifting fire regime on ecosystem carbon storage capacity in the interior Alaskan forests

    NASA Astrophysics Data System (ADS)

    Li, D.; Kelly, R.; Hu, F.; Luo, Y.

    2012-12-01

    Fire is the primary disturbance in the boreal forest, and variations in fire regimes have important ecological, biogeochemical, and socioeconomic implications. Recent widespread burning throughout the biome has been convincingly linked to climatic warming, with expectations of increased burning with future climate change. However, fire-regime dynamics are scale-dependent, and it is unclear whether empirical climate-fire relationships derived from the short observational record are applicable to future projections. Paleo-fire reconstructions offer a valuable extension to historical fire records by providing a context for ongoing change and offering insights to the causes and consequences of fire regime shifts over decades to millennia. The main objectives of this study are to address 1) how fire regime shift impacts ecosystem C dynamics at a millennial time scale; and 2) which factor is more important in regulating the dynamics of ecosystem C storage capacity at decades to millennium scales among fire, CO2 and temperature. In this study, the REGIME model (Weng et al. JGR, 2012) has been modified to evaluate the dynamics of ecosystem C storage capacity (the theoretic capacity of an ecosystem to store C) since 3000 years BP for the black spruce forests in interior Alaska under the influence of changing fire regime, rising atmospheric CO2 concentration, and climate warming, all of which were derived from paleo-data. In addition, C storage capacity was also modeled through the 21 century using IPCC scenarios for CO2 and temperature, and fire regime scenario derived based on a paleo-fire dataset. Overall, fire frequency has been constant but fire severity has increased significantly since 3000 years BP for the studied area. Our results indicate that this fire regime shifting alone or in combination with temperature and/or CO2 always decrease ecosystem C storage capacity over the past 3000 years. Among the single factors, fire regime shifting results in the greatest

  2. Scaling up from traits to communities to ecosystems across broad climate gradients: Testing Metabolic Scaling Theories predictions for forests

    NASA Astrophysics Data System (ADS)

    Enquist, B. J.; Michaletz, S. T.; Buzzard, V.

    2015-12-01

    Key insights in global ecology will come from mechanistically linking pattern and process across scales. Macrosystems ecology specifically attempts to link ecological processes across spatiotemporal scales. The goal s to link the processing of energy and nutrients from cells all the way ecosystems and to understand how shifting climate influences ecosystem processes. Using new data collected from NSF funded Macrosystems project we report on new findings from forests sites across a broad temperature gradient. Our study sites span tropical, temperate, and high elevation forests we assess several key predictions and assumptions of Metabolic Scaling Theory (MST) as well as several other competing hypotheses for the role of climate, light, and plant traits on influencing forest demography and forest ecosystems. Specifically, we assess the importance of plant size, light limitation, size structure, and various climatic factors on forest growth, demography, and ecosystem functioning. We provide some of the first systematic tests of several key predictions from MST. We show that MST predictions are largely upheld and that new insights from assessing theories predictions yields new observations and findings that help modify and extend MST's predictions and applicability. We discuss how theory is critically needed to further our understanding of how to scale pattern and process in ecology - from traits to ecosystems - in order to develop a more predictive global change biology.

  3. Comparison of Forest and Tundra Ecosystems Npp with Remote Sensing and Ground Observation Data

    NASA Astrophysics Data System (ADS)

    Ivanova, Yuliya; Ovchinnikova, Nataly; Kryazhimskiy, Fedor; Maklakov, Kirill

    2012-07-01

    In this study we compared two models for NPP estimate: an estimate based on satellite data and an estimate based on biomass calculation for tundra in the Yamal Peninsula and for forest ecosystems at the West Sayan Mountains. Ground NPP estimates were done for the same study areas which made it possible to identify the most significant parameters, specific to each model, that affect the estimates. The main difficulty in NPP-related studies is that current NPP values in an ecosystem cannot be determined exactly. Estimates, however, are feasible, and they can be made using a variety of methods. Thus, it seems important to see the ways in which these methods are different from each other and to find out how close the resulting values are. If these are dissimilar, the parameters used to make NPP estimates should be compared in order to identify the stage that can give rise to defects and errors, and to under- and overestimates. In this study we estimated NPP using the following two approaches: NPP calculation based on ground-truth measurements, such as calculation of plant phytomass on the studied area based on morphometric measurements (height, stem diameter, crown volume, etc.) and variations in this phytomass over a certain time period. NPP calculation based on satellite remote sensing data, using the data of satellite spectral channels and the data on underlying terrain. In this study we used MODIS/TERRA 8-day composite images, namely MOD09A1 and MOD11A2, with the spatial resolution 500 m and 1 km, respectively, obtained from EOS Data Gateway. Different models evaluate NPP using different physical values, with dissimilar temporal and spatial distributions. The NPP values evaluated by two models differ inherently. We used both of the models: GLO-PEM end MODIS-NPP. The study area is situated in the south of the Krasnoyarskii Krai, at the West Sayan Mountains, where the Institute of Forest SB RAS has been conducting observations since 1960. In this area altitudinal

  4. Chemosynthetic ecosystems study. Final report. Volume 3. Appendices

    SciTech Connect

    MacDonald, I.R.; Sager, W.W.; Lee, C.; Schroeder, W.W.; Kennicutt, M.C.

    1995-06-01

    Volume III presents ancillary materials from the findings of a three year investigation of the geology, chemistry and biology of chemosynthetic ecosystems in the Gulf of Mexico. These dense assemblages of tube worms, mussels and/or clams are primarily dependent upon chemical conditions generated by natural oil and gas seeps. Hydrocarbon seeps produce a variety of distinctive geological features including carbonate rock, mud volcanoes and hydrate mounds, which tend to be localized to areas less than 1 km. The interaction of the sediment bacteria with the hydrocarbons in the seafloor yields a highly specialized chemical environment featuring high levels of hydrogen sulfide and degraded oils. The biological community is supported by chemoautotrophic bacteria that live symbiotically with tube worms, mussels and clams.

  5. Chemosynthetic ecosystems study. Final report. Volume 2. Technical report

    SciTech Connect

    MacDonald, I.R.; Sager, W.W.; Lee, C.; Schroeder, W.W.; Kennicutt, M.C.

    1995-06-01

    Volume II presents detailed findings of a three year investigation of the geology, chemistry and biology of chemosynthetic ecosystems in the Gulf of Mexico. These dense assemblages of tube worms, mussels and/or clams are primarly dependent upon chemical conditions generated by natural oil and gas seeps. Hydrocarbon seeps produce a variety of distinctive geological features including carbonate rock, mud volcanoes and hydrate mounds, which tend to be localized to areas less than 1 km. The interaction of the sediment bacteria with the hydrocarbons in the seafloor yields a highly specialized chemical environment featuring high levels of hydrogen sulfide and degraded oils. The biological community is supported by chemoautotrophic bacteria that live symbiotically with tube worms, mussels and clams. The bacteria derive energy for fixing new carbon by oxidizing sulfides or methane.

  6. [Effect of seasonal high temperature and drought on carbon flux of bamboo forest ecosystem in subtropical region].

    PubMed

    Chen, Xiao-feng; Jiang, Hong; Niu, Xiao-dong; Zhang, Jin-meng; Liu, Yu-li; Fang, Cheng-yuan

    2016-02-01

    The carbon flux of subtropical bamboo forest ecosystem was continuously measured using eddy covariance technique in Anji County of Zhejiang Province, China. The monthly net ecosystem productivity (NEP), ecosystem respiration (Re) and gross ecosystem productivity (GEP) data from 2011 to 2013 were selected to analyze the impacts of seasonal high temperature and drought on the carbon flux of bamboo forest ecosystem. The results showed that there were big differences among annual NEP of bamboo forest from 2011 to 2013. Because of the asynchronization of precipitation and heat, the seasonal high temperature and drought in July and August of 2013 caused significant decline in NEP by 59.9% and 80.0% when compared with the same months in 2011. Correlation analysis of the NEP, Re, GEP and environmental factors suggested that the atmosphere temperatures were significantly correlated with Re and GEP in 2011 and 2013 (P<0.05). However, to air and soil moisture, Re and GEP had different responses, that was, GEP was more vulnerable by the decrease of the soil moisture compared with Re. Besides, the raising of saturation vapour pressure promoted the Re modestly but inhibited the GEP, which was supposed to be the main reason for NEP decrease of bamboo forest ecosystem in Anji, from July to August in 2013.

  7. [Effect of seasonal high temperature and drought on carbon flux of bamboo forest ecosystem in subtropical region].

    PubMed

    Chen, Xiao-feng; Jiang, Hong; Niu, Xiao-dong; Zhang, Jin-meng; Liu, Yu-li; Fang, Cheng-yuan

    2016-02-01

    The carbon flux of subtropical bamboo forest ecosystem was continuously measured using eddy covariance technique in Anji County of Zhejiang Province, China. The monthly net ecosystem productivity (NEP), ecosystem respiration (Re) and gross ecosystem productivity (GEP) data from 2011 to 2013 were selected to analyze the impacts of seasonal high temperature and drought on the carbon flux of bamboo forest ecosystem. The results showed that there were big differences among annual NEP of bamboo forest from 2011 to 2013. Because of the asynchronization of precipitation and heat, the seasonal high temperature and drought in July and August of 2013 caused significant decline in NEP by 59.9% and 80.0% when compared with the same months in 2011. Correlation analysis of the NEP, Re, GEP and environmental factors suggested that the atmosphere temperatures were significantly correlated with Re and GEP in 2011 and 2013 (P<0.05). However, to air and soil moisture, Re and GEP had different responses, that was, GEP was more vulnerable by the decrease of the soil moisture compared with Re. Besides, the raising of saturation vapour pressure promoted the Re modestly but inhibited the GEP, which was supposed to be the main reason for NEP decrease of bamboo forest ecosystem in Anji, from July to August in 2013. PMID:27396103

  8. Effects of Conversion from Boreal Forest to Arctic Steppe on Soil Communities and Ecosystem Carbon Pools

    NASA Astrophysics Data System (ADS)

    Han, P. D.; Natali, S.; Schade, J. D.; Zimov, N.; Zimov, S. A.

    2014-12-01

    The end of the Pleistocene marked the extinction of a great variety of arctic megafauna, which, in part, led to the conversion of arctic grasslands to modern Siberian larch forest. This shift may have increased the vulnerability of permafrost to thawing because of changes driven by the vegetation shift; the higher albedo of grassland and low insulation of snow trampled by animals may have decreased soil temperatures and reduced ground thaw in the grassland ecosystem, resulting in protection of organic carbon in thawed soil and permafrost. To test these hypothesized impacts of arctic megafauna, we examined an experimental reintroduction of large mammals in northeast Siberia, initiated in 1988. Pleistocene Park now contains 23 horses, three musk ox, one bison, and several moose in addition to the native fauna. The park is 16 square km with a smaller enclosure (< 1 km) where animals spend most of their time and our study was focused. We measured carbon-pools in forested sites (where scat surveys showed low animal use), and grassy sites (which showed higher use), within the park boundaries. We also measured thaw depth and documented the soil invertebrate communities in each ecosystem. There was a substantial difference in number of invertebrates per kg of organic soil between the forest (600 ± 250) and grassland (300 ± 250), though these differences were not statistically significant they suggest faster nutrient turnover in the forest or a greater proportion of decomposition by invertebrates than other decomposers. While thaw depth was deeper in the grassland (60 ± 4 cm) than in the forest (40 ± 6 cm), we did not detect differences in organic layer depth or percent organic matter between grassland and forest. However, soil in the grassland had higher bulk density, and higher carbon stocks in the organic and mineral soil layers. Although deeper thaw depth in the grassland suggests that more carbon is available to microbial decomposers, ongoing temperature monitoring

  9. Net Ecosystem Carbon Exchange and Evapotranspiration After the Felling of an Eucalyptus Forest

    NASA Astrophysics Data System (ADS)

    Pita, Gabriel; Rodrigues, Abel; Mateus, Antonio; Pereira, Santos J.

    2011-01-01

    Espirra site (38o38’N,8o36’W) is located in a 300ha Eucalyptus globulus plantation, with a Mediterranean type climate with a mean annual precipitation of 709mm and a mean annual air temperature of 15.9oC. The plantation was established in 1986 with about 1100 trees ha-1. A 33m observation tower was installed in 2002, with an eddy covariance system. A harvesting of trees was made at the end of the 2nd rotation period, from November to December 2006. During the last four years of the second rotation the coppice were 20m height. Harvesting was planned in order to initiate a new 12 year productive cycle. In October 2008 a first thinning was made in three fourths of emerging stems from stumps. At this stage the forest trees had a mean height of 6m. During the period of analyses the total annual precipitation has varied between a minimum of 248mmYr-1 (2005) to a maximum of 796mm Yr-1 (2007), pattern typical of a Mediterranean climate. The diminution of precipitation (and also how it is distributed along the year) affects the forest uptake of Carbon .The GPP and the TER show lower values in dry years, both in the adult forest as in the young one. The GPP of the growing eucalyptus has been affected by the dry year but also by the thinning that took place in Oct 2008. The Ecosystem total respiration shows high values after the felling ( the same order of magnitude as the forest before the felling) due to the leaves and branches that were left over the soil after the harvesting. Three years after the felling the GPP of the young forest is 61% the value of the adult forest (mean value, excluding the dry year). The seasonal pattern of TER is similar before and after the felling, but in the young forest the GPP is lower and the NEE becomes positive in winter time. In an annual base the growing eucalyptus forest only in the first year after felling was a source of carbon.

  10. On Estimating Crop Coefficients and Decoupling Factors of Forest Ecosystems in East Asia

    NASA Astrophysics Data System (ADS)

    Kang, M.; Kim, J.; Kwon, H.; Hirano, T.; Saigusa, N.; Takagi, K.; Yu, G.

    2012-12-01

    For effective water management, the quantification of evapotranspiration (ET) is imperative. Considering the difficulty of measurement and adequate simulation of ET in large areas, the crop coefficients (Kc=ETc adj/ETo/Ks; where ETc adj is the adjusted evapotranspiration, ETo is the reference crop evapotranspiration estimated by the FAO56-PM method, and Ks is the water stress coefficient) and the decoupling factors (Ω=ETa/ETp; where ETa is the actual evapotranspiration, and ETp is the potential evapotranspiration estimated by the Penman-Monteith equation) are valuable information for the assessment of regional ET. In this study, we determined the Kc and Ω of seven forest ecosystems in East Asia (i.e., temperate and coniferous forests in Gwangneung, Korea, GDK and GCK, respectively; cool temperate forests in Changbaishan, China, CBS, in Takayama and Teshio, Japan, TKY and TSE, respectively; subtropical forest in Xishuangbanna, Southern China, BNS; tropical forest in Palangkaraya, Indonesia, PDF) using the multi-year observed ET by eddy covariance technique. Annual ETo ranged from 443 mm at the TKY site to 1368 mm at the PDF site. Annual ETp ranged from 835 mm at the TSE site to 2466 mm at the PDF site. The Kc and Ω for the (cool) temperate forests showed a clear seasonality with the minimum (~0.3 of Kc and ~0 of Ω) in winter and the maximum in summer or early autumn. The maxima of Kc were different among the sites and ranged from 0.6 at the TSE site to 1.2 at the BNS site. Unlike the maximum Kc, the maxima of Ω were similar among the temperate forests (0.4~0.5) and between the tropical forests (~0.6). Implications of the results are discussed in terms of usefulness and accuracy of using Kc and Ω. Acknowledgement - This study was supported by the Korea Meteorological Administration Research and Development Program under Grant CATER 2012-3030. The flux database was provided by CarboEastAsia - A3 Foresight Program and KoFlux.

  11. Effects and Feedbacks of Windthrow/breaks in Boreal Forest Ecosystems

    NASA Astrophysics Data System (ADS)

    Panferov, O.; Sogachev, A.; Radler, K.; Oltchev, A.; Gravenhorst, G.

    2008-12-01

    The increased frequency of severe storms (Leckebusch et al., 2007) as a result of ongoing climate change, results in a wide area damage events within boreal forest ecosystems. The damage occurs at exposed forest edges as well as inside forest stands creating the gaps. Once a windthrow/break gap occurs, it results in changes of surface albedo and microclimatological conditions and in increasing wind stress on remaining trees around the gap which in turn increase the risk of further wind damage. The self-induced growth of windthrow gap provides other positive as well as negative feedbacks to climate forcing at different spatial and temporal scales as shown in Vygodskaya et al., 2007, e.g. an increase of CO2 efflux (climate warming) and an increase of surface albedo (climate cooling). The present study characterizes the spatial variation of wind load and the changes in radiative regime (surface albedo) within the damaged forest stand. For description of wind field and load on trees the atmospheric boundary-layer two-equation closure model SCADIS based on transport equations for turbulent kinetic energy (E) and specific dissipation (omega) (E-omega model), which accounts for the flow dynamics within a plant canopy (Panferov and Sogachev, 2008; Sogachev and Panferov, 2006) was used. The radiative regime within the damaged forest is described by means of a three-dimensional radiation transfer model SPM3D (Panferov et al., 2005). A series of numerical experiments with circular and rectangular forest gaps with sizes from 3 to 75 tree heights, h, have been carried out for a modelled boreal forest. To evaluate the changes produced by gaps relatively to undisturbed forest all characteristics were normalized by their values for the latter. The results of the study show that the magnitude of wind load on trees surrounding the newly created forest gaps increases with gap size and is app. 7 times higher than the load on trees in an undisturbed forest. The gust component of wind

  12. Water Fluxes from Leaf to Ecosystem Scales in a Seasonal Mexican Cloud Forest: Implications for Climate Change Impacts and Future Research Priorities

    NASA Astrophysics Data System (ADS)

    Asbjornsen, H.; Gotsch, S. G.; Goldsmith, G. R.; Alvarado-Barrientos, M. S.; Holwerda, F.; Bruijnzeel, L. A.; Dawson, T. E.

    2014-12-01

    The ecohydrological functioning of cloud forests is intricately linked to unique plant ecophysiological traits and processes that influence water fluxes at the plot to ecosystem scales. However, despite substantial gains in our understanding of cloud forest plant ecophysiology over the past decade, integration of water flux information from the leaf to the watershed scale is still lacking. We present a synthesis of research aimed at revealing the linkages between plant ecophysiology and forest ecohydrological functioning, conducted in a seasonal cloud forest in Veracruz, Mexico. A variety of species-specific leaf-level water flux behaviors were found to influence various aspects of plant water relations, which in turn, scaled up to impact stand water balance. For example, foliar fog absorption compensated for approximately 9.3 ± 1.2% of transpiration, and nocturnal transpiration for dominant tree species during the dry-season accounted for 22% to 30% of daytime transpiration. Further, the presence of dense fog, light fog, and cloud cover was shown to reduce transpiration such that annual transpiration may increase up to 17% in the case that all fog occurrence is replaced by clear sky conditions. We discuss how these processes affect whole-plant and stand water balances, as well as the potential feedbacks of vegetation controls on hydrologic fluxes under future climate change. After placing our findings within a global context we present a conceptual model of the links between plant ecophysiological and ecosystem hydrological functioning in cloud forest settings. Finally, critical areas for future research are highlighted to further improve our understanding of the linkages between leaf- and ecosystem-level processes and fluxes.

  13. Tree Death Leading To Ecosystem Renewal? Forecasting Carbon Storage As Eastern Forests Age

    NASA Astrophysics Data System (ADS)

    Curtis, P.; Gough, C. M.; Bohrer, G.; Nadelhoffer, K. J.; Ivanov, V. Y.

    2013-12-01

    The future trajectory of North American carbon (C) stocks remains uncertain as a subset of maturing trees die in mixed deciduous forests of the U.S. Midwest and East transitioning from early to middle and late succession. We are studying disturbance-structure-function relationships of aging forests in northern Michigan using long-term ecological and meteorological C cycling studies, a large-scale disturbance experiment, a 200-year forest chronosequence, and flux comparisons across three tower sites. We find that ecosystem responses to mortality are characterized by several processes that affect structure-function relationships and alter the way ecosystem functioning interacts with meteorological forcing. We subjected 39 ha of forest to moderate experimental disturbance, similar to that of age-related or climatically induced tree mortality. We found that the mortality of a third of all canopy trees minimally altered the balance between forest C uptake and release, as growth-limiting light and nitrogen resources were rapidly reallocated from dead and dying trees to undisturbed trees. Although disturbance-induced mortality increased soil N mineralization rates, nitrification, and denitrification, N exports from soils remained low. Upper canopy gap formation and a rise in structural complexity allowed increased photosynthetic contribution of sub-canopy vegetation to compensate for the death of canopy dominant trees. However, we found large differences between the transpirational response of maples and oaks to VPD and soil moisture, which led to relative declines in maple transpiration post-disturbance. These hydrologic differences may affect a species' ability to compete for resources following such a disturbance. Changes to canopy structure had a relatively small effect on roughness length and the turbulence forcing of fluxes from the canopy. We currently are studying how tree mortality driven changes in canopy structure affects within-canopy resource distribution and

  14. Characterization of Forest Ecosystems by combined Radiative Transfer Modeling for Imaging Spectrometer and LiDAR

    NASA Astrophysics Data System (ADS)

    Koetz, B.; Sun, G.; Morsdorf, F.; Rubio, J.; Kimes, D.; Ranson, J.

    2009-04-01

    This research was motivated by the increased information dimensionality provided by current Earth Observation systems measuring the complex and dynamic medium of the vegetated surface of the Earth. Advanced and reliable algorithms that fully exploit this enhanced Earth Observation information are needed to deliver consistent data sets of the Earth vegetation condition describing its spatial distribution and change over time. Spectral observation provided by imaging spectrometers and the waveform from large-footprint LiDAR are now available from space for forest ecosystem studies. The imaging spectrometer data contains information about the biochemical composition of the canopy foliage, and is widely used to estimate biophysical canopy parameters such as LAI and fractional cover. LiDAR responds to the vertical distribution of scatters and permits inferences about the plant structures required to supply water and mechanical support to those surfaces. Various canopy height indices derived from LiDAR waveform have been successfully used to infer forest above-ground biomass and the characterization of canopy structure. The structure parameters derived from LiDAR data can improve the accuracy and robustness of canopy parameter retrieval from imaging spectrometer by reducing uncertainties related to the canopy structure. The specific information content, inherent to the observations of imaging spectrometry and LIDAR, assesses thus different but complementary characteristics of the complex vegetation canopy. The combination of these two information dimensions offers a unique and reliable canopy characterization including information relevant to different aspects of the biochemical and biophysical properties and thus understanding of processes within forest ecosystems. A comprehensive canopy characterization of a forest ecosystem is derived from the combined remote sensing signal of imaging spectrometry and large footprint LIDAR. The inversion of two linked physically based

  15. Simulated Net Ecosystem Carbon Balance of Western US Forests Under Contemporary Climate and Management

    NASA Astrophysics Data System (ADS)

    Yang, Z.; Law, B. E.; Jones, M. O.

    2015-12-01

    Previous projections of the contemporary forest carbon balance in the western US showed uncertainties associated with impacts of climate extremes and a coarse spatio-temporal resolution implemented over heterogeneous mountain regions. We modified the Community Land Model (CLM) 4.5 to produce 4km resolution forest carbon changes with drought, fire and management in the western US. We parameterized the model with species data using local plant trait observations for 30 species. To quantify uncertainty, we evaluated the model with data from flux sites, inventories and ancillary data in the region. Simulated GPP was lower than the measurements at our AmeriFlux sites by 17-22%. Simulated burned area was generally higher than Landsat observations, suggesting the model overestimates fire emissions with the new fire model. Landsat MTBS data show high severity fire represents only a small portion of the total burnt area (12-14%), and no increasing trend from 1984 to 2011. Moderate severity fire increased ~0.23%/year due to fires in the Sierra Nevada (Law & Waring 2014). Oregon, California, and Washington were a net carbon sink, and net ecosystem carbon balance (NECB) declined in California over the past 15 years, partly due to drought impacts. Fire emissions were a small portion of the regional carbon budget compared with the effect of harvest removals. Fossil fuel emissions in CA are more than 3x that of OR and WA combined, but are lower per capita. We also identified forest regions that are most vulnerable to climate-driven transformations and to evaluate the effects of management strategies on forest NECB. Differences in forest NECB among states are strongly influenced by the extent of drought (drier longer in the SW) and management intensity (higher in the PNW).

  16. Relating injury to the forest ecosystem near Palmerton, PA, to zinc contamination from smelting.

    PubMed

    Beyer, W Nelson; Krafft, Cairn; Klassen, Stephen; Green, Carrie E; Chaney, Rufus L

    2011-10-01

    The forest on Blue Mountain, near Lehigh Gap, has been injured by emissions from two historical zinc (Zn) smelters in Palmerton, PA, located at the northern base of the mountain. The uppermost mineral soil and lower litter from sites along a transect, just south of the ridgetop, contained from 64 to 4400 mg/kg Zn. We measured forest metrics at 15 sampling sites to ascertain how forest structure, species composition and regeneration are related to soil concentrations of Zn, the probable principal cause of the injury. Understanding how ecotoxicological injury is related to soil Zn concentrations helps us quantify the extent of injury to the ecosystem on Blue Mountain as well as to generalize to other sites. The sum of canopy closure and shrub cover, suggested as a broadly inclusive measure of forest structure, was decreased to half at approximately 2060 mg/kg Zn (102 mg/kg Sr(N0(3))(2)-extractable Zn). Tree-seedling density was decreased by 80% (from 10.5/m(2) to 2.1/m(2)) at a much lower concentration: 1080 mg/kg Zn (59 mg/kg Sr(N0(3))(2)-extractable Zn). Changes in species composition and richness were not as useful for quantifying injury to the forest. Phytotoxicity, desiccation from exposure, and a gypsy moth infestation combined to form a barren area on the ridgetop. Liming the strongly acid Hazleton soils at the sites would partially ameliorate the observed phytotoxicity and should be considered in planning restoration.

  17. Temperature sensitivity of soil carbon dioxide and nitrous oxide emissions in mountain forest and meadow ecosystems in China

    NASA Astrophysics Data System (ADS)

    Zhang, Junjun; Peng, Changhui; Zhu, Qiuan; Xue, Wei; Shen, Yan; Yang, Yanzheng; Shi, Guohua; Shi, Shengwei; Wang, Meng

    2016-10-01

    An incubation experiment was conducted at three temperature levels (8, 18 and 28 °C) to quantify the response of soil CO2 and N2O emissions to temperature in three ecosystems (pine forest, oak forest, and meadow) located in the Qinling Mountains of China, which are considered to be susceptible to disturbance and climate changes, especially global warming. The soil CO2 emission rates increased with temperature and decreased with soil depth; they were the highest in the oak forest (broadleaf forest) and were lower in the pine forest (coniferous forest) and the meadow ecosystem. However, there was no significant difference in the soil N2O emission rates among the three ecosystems. The temperature sensitivity of CO2 and N2O was higher in the forest than in the meadow ecosystem. The Q10 values (temperature sensitivity coefficient) for CO2 and N2O were 1.07-2.25 and 0.82-1.22, respectively, for the three ecosystems. There was also evidence that the CO2 and N2O emission rates were positively correlated. The soil characteristics exhibited different effects on CO2 and N2O emissions among different ecosystems at the three temperature levels. Moreover, the soil dissolved organic carbon (DOC), specific ultraviolet absorbance (SUVA) and nitrate (NO3-) were important factors for CO2 emissions, whereas the soil ammonium (NH4+) and pH were the major controllers of N2O emissions. Unexpectedly, our results indicated that CO2 emissions are more sensitive to increasing temperature than N2O, noting the different feedback of CO2 and N2O emissions to global warming in this region. The different responses of greenhouse gas emissions in different forest types and a meadow ecosystem suggest that it is critical to conduct a comprehensive investigation of the complex mountain forest and meadow ecosystem in the transitional climate zone under global warming. Our research results provide new insight and advanced understanding of the variations in major greenhouse gas emissions (CO2 and N2O

  18. An assessment of restoration success to forests planted for ecosystem restoration in loess plateau, Northwestern China.

    PubMed

    Yang, Zhanbiao; Jin, Hongxi; Wang, Gang

    2010-05-01

    Using ecosystem attributes identified by the Society of Ecological Restoration International, we assessed three restoration projects in the loess plateau, northwestern China, including planting Larix principis-rupprechtii (LS) and Pinus tabulaeformis (PS) on shrubland, and planting L. principis-rupprechtii on open forest land (LO). The reestablishment of native species in LS and PS was poorer than LO because of the excessive stand density. Species diversity, seedling number, and seedling diversity were significantly higher in LO than in LS and PS. Soil nutrient was also significantly higher in the LO treatment. The vegetation composition, species diversity, and soil nutrient in LO, however, were more similar to these in the reference. Our results indicate that planting L. principis-rupprechtii on open forest land had accelerated the succession of the ecosystem for approximately 30 years. But the poor natural regeneration of L. principis-rupprechtii suggests that post-planting activities in LO are required after timber harvesting or the natural mortality of the L. principis-rupprechtii. Management operation such as selective thinning will be required in LS and PS to promote the true restoration of native species diversity in the future.

  19. Primates as Predictors of Mammal Community Diversity in the Forest Ecosystems of Madagascar

    PubMed Central

    Muldoon, Kathleen M.; Goodman, Steven M.

    2015-01-01

    The geographic distribution of species is the typical metric for identifying priority areas for conservation. Since most biodiversity remains poorly studied, a subset of charismatic species, such as primates, often stand as surrogates for total biodiversity. A central question is therefore, how effectively do primates predict the pooled species richness of other mammalian taxa? We used lemurs as indicator species to predict total non-primate mammal community richness in the forest ecosystems of Madagascar. We combine environmental and species occurrence data to ascertain the extent to which primate diversity can predict (1) non-primate mammal α-diversity (species richness), (2) non-primate complementarity, and (3) non-primate β-diversity (species turnover). Our results indicate that primates are effective predictors of non-primate mammal community diversity in the forest ecosystems of Madagascar after controlling for habitat. When individual orders of mammals are considered, lemurs effectively predict the species richness of carnivorans and rodents (but not afrosoricids), complementarity of rodents (but not carnivorans or afrosoricids), and all individual components of β-diversity. We conclude that lemurs effectively predict total non-primate community richness. However, surrogate species alone cannot achieve complete representation of biodiversity. PMID:26334525

  20. A Study of Effects of Acid Deposition on Pine Forest Ecosystem in Southwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Li, F.; Lv, Z.; Song, W.; Yang, S.

    2013-12-01

    We used a long-term soil acidification model (LTSAM) and a terrestrial biogeochemical model (CENTURY) coupled to simulate the effects of acid deposition on pine forest ecosystem in southwestern China, based on indoor experiment results of aluminum toxicity to individual plant growth. The results of indoor aluminum experiments show that high aluminum concentration may restrict the plant growth and the acidic condition may aggravate it. The behavior of restriction of plant growth includes decreases of pine seedling biomass, root elongation and the sorption of soil cations (e.g. Ca2+, Mg2+, Na+ and K+). The model simulation results about soil chemistry show that, as acid deposition increases more, the pH value decreases faster, the soil aluminum ion concentration increase more rapidly, and the nutrition ions in soil solution decrease more quickly. The increased acid deposition also has negative impacts on the forest ecosystem according to the biogeochemical model simulation, for example, decreases of vegetation biomass, net primary productivity (NPP) and net CO2 uptake. Furthermore, the decrease of plant biomass will result in the decrease of the soil organic carbon content for the limited decomposition material supply.

  1. Importance of terrestrial arthropods as subsidies in lowland Neotropical rain forest stream ecosystems

    USGS Publications Warehouse

    Small, Gaston E.; Torres, Pedro J.; Schwizer, Lauren M.; Duff, John H.; Pringle, Catherine M.

    2013-01-01

    The importance of terrestrial arthropods has been documented in temperate stream ecosystems, but little is known about the magnitude of these inputs in tropical streams. Terrestrial arthropods falling from the canopy of tropical forests may be an important subsidy to tropical stream food webs and could also represent an important flux of nitrogen (N) and phosphorus (P) in nutrient-poor headwater streams. We quantified input rates of terrestrial insects in eight streams draining lowland tropical wet forest in Costa Rica. In two focal headwater streams, we also measured capture efficiency by the fish assemblage and quantified terrestrially derived N- and P-excretion relative to stream nutrient uptake rates. Average input rates of terrestrial insects ranged from 5 to 41 mg dry mass/m2/d, exceeding previous measurements of aquatic invertebrate secondary production in these study streams, and were relatively consistent year-round, in contrast to values reported in temperate streams. Terrestrial insects accounted for half of the diet of the dominant fish species, Priapicthys annectens. Although terrestrially derived fish excretion was found to be a small flux relative to measured nutrient uptake rates in the focal streams, the efficient capture and processing of terrestrial arthropods by fish made these nutrients available to the local stream ecosystem. This aquatic-terrestrial linkage is likely being decoupled by deforestation in many tropical regions, with largely unknown but potentially important ecological consequences.

  2. An assessment of restoration success to forests planted for ecosystem restoration in loess plateau, Northwestern China.

    PubMed

    Yang, Zhanbiao; Jin, Hongxi; Wang, Gang

    2010-05-01

    Using ecosystem attributes identified by the Society of Ecological Restoration International, we assessed three restoration projects in the loess plateau, northwestern China, including planting Larix principis-rupprechtii (LS) and Pinus tabulaeformis (PS) on shrubland, and planting L. principis-rupprechtii on open forest land (LO). The reestablishment of native species in LS and PS was poorer than LO because of the excessive stand density. Species diversity, seedling number, and seedling diversity were significantly higher in LO than in LS and PS. Soil nutrient was also significantly higher in the LO treatment. The vegetation composition, species diversity, and soil nutrient in LO, however, were more similar to these in the reference. Our results indicate that planting L. principis-rupprechtii on open forest land had accelerated the succession of the ecosystem for approximately 30 years. But the poor natural regeneration of L. principis-rupprechtii suggests that post-planting activities in LO are required after timber harvesting or the natural mortality of the L. principis-rupprechtii. Management operation such as selective thinning will be required in LS and PS to promote the true restoration of native species diversity in the future. PMID:19373438

  3. Functional composition drives ecosystem function through multiple mechanisms in a broadleaved subtropical forest.

    PubMed

    Chiang, Jyh-Min; Spasojevic, Marko J; Muller-Landau, Helene C; Sun, I-Fang; Lin, Yiching; Su, Sheng-Hsin; Chen, Zueng-Sang; Chen, Chien-Teh; Swenson, Nathan G; McEwan, Ryan W

    2016-11-01

    Understanding the role of biodiversity (B) in maintaining ecosystem function (EF) is a foundational scientific goal with applications for resource management and conservation. Two main hypotheses have emerged that address B-EF relationships: niche complementarity (NC) and the mass-ratio (MR) effect. We tested the relative importance of these hypotheses in a subtropical old-growth forest on the island nation of Taiwan for two EFs: aboveground biomass (ABG) and coarse woody productivity (CWP). Functional dispersion (FDis) of eight plant functional traits was used to evaluate complementarity of resource use. Under the NC hypothesis, EF will be positively correlated with FDis. Under the MR hypothesis, EF will be negatively correlated with FDis and will be significantly influenced by community-weighted mean (CWM) trait values. We used path analysis to assess how these two processes (NC and MR) directly influence EF and may contribute indirectly to EF via their influence on canopy packing (stem density). Our results indicate that decreasing functional diversity and a significant influence of CWM traits were linked to increasing AGB for all eight traits in this forest supporting the MR hypothesis. Interestingly, CWP was primarily influenced by NC and MR indirectly via their influence on canopy packing. Maximum height explained more of the variation in both AGB and CWP than any of the other plant functional traits. Together, our results suggest that multiple mechanisms operate simultaneously to influence EF, and understanding their relative importance will help to elucidate the role of biodiversity in maintaining ecosystem function. PMID:27632194

  4. Characterization of organic matter in rainfall, throughfall, stemflow, and streamwater from three subtropical forest ecosystems

    NASA Astrophysics Data System (ADS)

    Wang, M. C.; Liu, C. P.; Sheu, B. H.

    2004-04-01

    Little is known about the characteristics of dissolved organic matter derived from precipitation, throughfall, stemflow, and streamwater in subtropical forest ecosystems. Water samples were, thus, collected from rainfall, throughfall and stemflow of a China-fir plantation, a secondary hardwood and a natural hardwood, and streams in forest ecosystems in the central part of subtropical Taiwan on March 31 and May 8, 1999. We examined pH, electrical conductivity, dissolved organic carbon, and acid-neutralizing capacity (ANC) in the samples. Furthermore, the humic polymers (MW>1000) and fulvic acids (FAs; MW>1000) were isolated from the water samples and characterized by elemental analyses and Fourier transform infrared (FTIR) spectroscopy. Results showed that the contents of carboxylic acid of both humic polymers (MW>1000) and FAs (MW>1000) contributed to the water sample ANC, ranging from 8.7 to 61.2% and 0.2 to 38.1%, respectively. FTIR and elemental analyses of isolated humic polymers (MW>1000) and FAs (MW>1000) from throughfall and stemflow had characteristics previously reported for humic substances. The study showed that throughfall and stemflow, not affected by soils, may be additional sources of humic substances.

  5. Digging deeper: Fine root responses to rising atmospheric [CO2] in forested ecosystems

    SciTech Connect

    Iversen, Colleen M

    2010-01-01

    Experimental evidence from a diverse set of forested ecosystems indicates that CO2 enrichment may lead to deeper rooting distributions. While the causes of greater root production at deeper soil depths under elevated CO2 concentration ([CO2]) require further investigation, altered rooting distributions are expected to affect important ecosystem processes. The depth at which fine roots are produced may influence root chemistry, physiological function, and mycorrhizal infection, leading to altered nitrogen (N) uptake rates and slower turnover. Also, soil processes such as microbial decomposition are slowed at depth in the soil, potentially affecting the rate at which root detritus becomes incorporated into soil organic matter. Deeper rooting distributions under elevated [CO2] provide exciting opportunities to use novel sensors and chemical analyses throughout the soil profile to track the effects of root proliferation on carbon (C) and N cycling. Models do not currently incorporate information on root turnover and C and N cycling at depth in the soil, and modification is necessary to accurately represent processes associated with altered rooting depth distributions. Progress in understanding and modeling the interface between deeper rooting distributions under elevated [CO2] and soil C and N cycling will be critical in projecting the sustainability of forest responses to rising atmospheric [CO2].

  6. Staunton 1 reclamation demonstration project. Aquatic ecosystems. Final report

    SciTech Connect

    Vinikour, W. S.

    1981-02-01

    To provide long-term indications of the potential water quality improvements following reclamation efforts at the Staunton 1 Reclamation Demonstration Project, macroinvertebrates were collected from three on-site ponds and from the receiving stream (Cahokia Creek) for site drainage. Implications for potential benthic community differences resulting from site runoff were disclosed, but macroinvertebrate diversity throughout Cahokia Creek was limited due to an unstable, sandy substrate. The three ponds sampled were the New Pond, which was created as part of the reclamation activities; the Shed Pond, which and the Old Pond, which, because it was an existing, nonimpacted pond free of site runoff, served as a control. Comparisons of macroinvertebrates from the ponds indicated the potential for the New Pond to develop into a productive ecosystem. Macroinvertebrates in the New Pond were generally species more tolerant of acid mine drainage conditions. However, due to the present limited faunal densities and the undesirable physical and chemical characteristics of the New Pond, the pond should not be stocked with fish at this time.

  7. Contribution of ecosystem services to air quality and climate change mitigation policies: the case of urban forests in Barcelona, Spain.

    PubMed

    Baró, Francesc; Chaparro, Lydia; Gómez-Baggethun, Erik; Langemeyer, Johannes; Nowak, David J; Terradas, Jaume

    2014-05-01

    Mounting research highlights the contribution of ecosystem services provided by urban forests to quality of life in cities, yet these services are rarely explicitly considered in environmental policy targets. We quantify regulating services provided by urban forests and evaluate their contribution to comply with policy targets of air quality and climate change mitigation in the municipality of Barcelona, Spain. We apply the i-Tree Eco model to quantify in biophysical and monetary terms the ecosystem services "air purification," "global climate regulation," and the ecosystem disservice "air pollution" associated with biogenic emissions. Our results show that the contribution of urban forests regulating services to abate pollution is substantial in absolute terms, yet modest when compared to overall city levels of air pollution and GHG emissions. We conclude that in order to be effective, green infrastructure-based efforts to offset urban pollution at the municipal level have to be coordinated with territorial policies at broader spatial scales.

  8. Phosphorus cycling in forest ecosystems: insights from oxygen isotopes in phosphate

    NASA Astrophysics Data System (ADS)

    Pistocchi, Chiara; Tamburini, Federica; Bünemann, Else; Frossard, Emmanuel

    2015-04-01

    The current view on the phosphorus (P) cycle in forest ecosystems relies mostly on measurements and correlations of pools, and to a lower extent on measurement of fluxes. We have no direct insight into the processes phosphate goes through at the ecosystem level, and into the relative importance of organic and mineral pools in sustaining P nutrition of trees. The analysis of oxygen isotopes associated to P (18Op) is expected to bring this type of information. The German Priority Program SPP 1685 aims to test the overall hypothesis that the P-depletion of soils drives forest ecosystems from P acquiring systems (efficient mobilization of P from the mineral phase) to P recycling systems (highly efficient cycling of P). Our contribution to this project will consist in studying the relative importance of biological and geochemical processes in controlling the P cycle in temperate beech forest ecosystems in Germany along a gradient of decreasing soil P availability. We will follow the fate of phosphate from litter fall to the uptake of P by plants via P release by decomposition of organic matter or after release from P-containing minerals, by using a multi-isotope approach (O in water and phosphate plus 33P). To address our research question we will rely on measurements in experimental forest sites and on laboratory incubations of the organic layer or the mineral soil. We present here the first results issued from the 2014 sampling on three study sites, where we characterized the P pools in surface soil horizons by a sequential extraction (modified after Tiessen and Moir, 2007) and we analysed the 18Op of the resin extractable- and microbial-P fractions. Contrary to what was previously found (e.g. Tamburini et al. 2012) the isotopic composition of these fractions in most of the samples does not reflect the equilibrium value (as the result of the dominance of the pyrophosphatase activity on the other enzymatic processes, Blake et al. 2005). Depending on the P availability

  9. Mississippi/Alabama Pinnacle Trend Ecosystem Monitoring Final Synthesis Report

    USGS Publications Warehouse

    ,; Texas A&M University, Geochemical and Environmental Research Group

    2001-01-01

    This Final Synthesis Report summarizes a four-year program to characterize and monitor carbonate mounds on the Mississippi/Alabama outer continental shelf (OCS). The study area is shown in Fig.ES.1. The study was conducted by Continental Shelf Associates, Inc. and the Geochemical and Environmental Research Group (GERG) of Texas A&M University (TAMU), for the U.S. Geological Survey (USGS), Biological Resources Division.

  10. Effects of increased biomass removal on the biogeochemistry of two Norwegian forest ecosystems

    NASA Astrophysics Data System (ADS)

    Lange, H.; Clarke, N.; Kjønaas, O. J.; Aas, W.; Andreassen, K.; Børja, I.; Bratli, H.; Eich-Greatorex, S.; Eldhuset, T.; Holt-Hanssen, K.

    2009-04-01

    Increased removal of biomass from forested ecosystems for use as an alternative source of energy is an option in several countries. E.g., it is planned to double the use of bioenergy from all sources until 2020 in Norway. A large fraction of this increase is coming from forest resources, e.g. by removing harvest residues like branches and tops. This removal will reduce the supply of nutrients and organic matter to the forest soil, and may in the longer term increase the risk for future nutrient imbalance, soil erosion on steep slopes, reduced forest production, and changes in biodiversity and ground vegetation species composition. However, field experiments so far have found contrasting results in this respect. Soil effects of increased biomass removal will be closely related to soil organic matter (SOM) dynamics, litter quality, and turnover rates. Harvest intensity may affect the decomposition of existing SOM as well as the build-up of new SOM from litter and forest residues, by changing factors like soil temperature and moisture as well as amount and type of litter input. Changes in input of litter with different nutrient concentrations and decomposition patterns along with changes in SOM decomposition will affect the total storage of carbon, nitrogen and other vital nutrients in the soil. In the context of a Norwegian research project started in 2009, we will quantify how different harvesting regimes lead to different C addition to soil, and determine which factors have the greatest effect on decomposition of SOM under different environmental conditions. Two Norway spruce forest ecosystems will be investigated, one in eastern and one in western Norway, representing different climatic conditions and landscape types. At each location, two treatment regimes will be tested: (1) conventional harvesting (CH), with residues left on-site, and (2) aboveground whole-tree harvest (WTH), with branches, needles, and tops removed. Input of different forest residues will be

  11. Diversified forest ecosystems can grow on industrial waste residues: evidence from a multiproxy approach

    NASA Astrophysics Data System (ADS)

    Cortet, Jerome; Schwartz, Christophe; Echevarria, Guillaume; Nahmani, Johanne; Masfaraud, Jean-François; Ouvrard, Stéphanie; Sirguey, Catherine; Watteau, Francoise; Morel, Jean Louis

    2010-05-01

    Smelter activities in the Lorraine region (North-East France) have lead to the creation of flotation ponds that were used to eliminate wastes, mainly slag. After industrial decline, some of these flotation ponds were colonized by vegetation and evolved to forest ecosystems. One of these old flotation ponds, situated in Pompey, close to Nancy (North-East France), was studied by collecting information on several physico-chemical and biological indicators. The main objective was to understand the biological functioning of this system, whose soil can be classified as a pure Technosol, characterised by a very complex stratified profile created by successive slag deposits. Soil is characterized by its apparent heterogeneity, but also its high agronomic fertility and particularly high metal contents. Holorganic horizons can vary from one to several centimetres. Macrofauna is characterized by a very low abundance of earthworms and a dominance of millipedes. Furthermore, whereas earthworms do accumulate metals, this is not the case for millipedes. Mesofauna is typical of a temperate forest system, dominated by Collembola. Soil organo-mineral associations showed a high proportion of faecal pellets from Oribatid mites, Isopods and Diplopods. Furthermore, Mn, which is highly associated to metals (especially Zn and Pb) seems to play an important role in organo-mineral associations, including bacteria. An organic fraction is also directly associated to Calcium, Pb and Cu. Vegetation presents a high diversity, with more than 70 species, with very low metal transfer to plants. Results from soil respirometry are typical from temperate forest ecosystems. All this information has been combined to propose a model for the biochemical functioning of a such Technosol.

  12. Sensitivity of Southwestern US Mountain Ecosystems to Climate Variability: Interactions Among Forest Dieback, Fire, and Erosion

    NASA Astrophysics Data System (ADS)

    Allen, C. D.

    2004-12-01

    Millions of hectares in the upland landscapes of the Southwestern United States have been affected by forest dieback and severe fire activity since the late 1990s, a period of ongoing severe drought and unusual warmth. Climate regulates physiological plant stress that can directly cause vegetation mortality, and also influences associated insect outbreak dynamics. Climate also interacts with fuel conditions to drive regional fire activity. Current and historic patterns of forest dieback, fire activity, and erosion are described across landscape gradients in Southwestern mountains, particularly the Jemez Mountains of New Mexico. Methods used include inventory and dating of live and dead woody plants to assess demographic changes through time, long-term (since 1991) measurements of ponderosa pine tree-growth at three sites with dendrometer bands, monitoring of herbaceous vegetation along 3 km of permanent transects since 1991, aerial photograph analyses of insect outbreaks and forest dieback and fire activity, and hydrological measurements of runoff and erosion. Similarities and differences in vegetation dieback and regional fire activity patterns between the current drought and the 1950s (when regional drought last affected the Southwest) are explained by changes in climatic and vegetation conditions. The current climate-induced vegetation dieback and pulse of regional fire activity have strong feedbacks with various key ecosystem processes, including water budgets and soil erosion. For example, severe drought and fire both markedly reduce the surface cover of live plants and dead plant materials ("litter"), triggering nonlinear increases in erosion rates once the connectivity of bare soil patches exceeds critical threshold values, particularly during high-intensity summer rainfall events that characterize the Southwestern summer "monsoon". These observations highlight the magnitude, rapidity, and complexity of climate-induced disturbance processes, and provide an

  13. Contributions of Understory and Overstory to Ecosystem CO2 Fluxes in a Temperate Mixed Forest in Switzerland

    NASA Astrophysics Data System (ADS)

    Paul-Limoges, E.; Wolf, S.; Hörtnagl, L. J.; Eugster, W.; Buchmann, N. C.

    2015-12-01

    Forests play an important role in the global carbon cycle by sequestering large amounts of atmospheric CO2. The CO2 sequestered by a forest varies depending on many factors including climate, species composition, growth strategy, stand age and structure. Forests are structurally complex ecosystems, both horizontally and vertically. In many cases, several canopy layers with distinct functional properties and sun exposure contribute differently to the ecosystem CO2exchange. Only a few studies thus far have investigated the contribution of understory to overstory fluxes, and large variations have been found among sites. Our study focused on partitioning the net ecosystem CO2 flux of a mixed deciduous forest in Switzerland into its understory and overstory components using below and above canopy eddy-covariance (EC) measurements over two years. CO2 concentration profile measurements made at eight levels within the canopy complemented those measurements. We quantified the CO2flux contribution from the understory to the overstory, both in terms of photosynthesis and respiration, and assessed the differences between understory and overstory functional responses to environmental drivers. On an annual basis, the understory was a CO2 source, while the overstory was a CO2 sink. The understory was a CO2 sink only in spring with the early emergence of understory plants before overstory canopy leaf-out. Overall, the understory contributed 54% to annual ecosystem respiration but only 7% to annual ecosystem photosynthesis. Moreover, understory and overstory fluxes became decoupled at full canopy closure, thus leading to unaccounted EC fluxes when measured only above the canopy. CO2 concentration profile measurements supported this finding. Our results showed that understory EC measurements are essential in this mixed deciduous forest, and likely in many other forests, to fully understand the carbon dynamics within structurally complex ecosystems.

  14. Soil respiration dynamics under reduced rainfall in a eucalypt forest ecosystem in SE-Australia

    NASA Astrophysics Data System (ADS)

    Hinko-Najera, N.; Arndt, S. K.; Livesley, S. J.; Fest, B.

    2011-12-01

    Soil respiration is the major pathway by which CO2 is released from a forest ecosystem to the atmosphere. Hence it is a central part of the carbon balance and carbon sink strengths of forests. Soil respiration shows high spatial and temporal variability and is dependent on soil temperature and soil moisture. Its component fluxes are controlled by different carbon sources: decomposition of soil organic matter or litter (heterotrophic respiration) or allocation of assimilated carbon belowground (autotrophic respiration). As such, these processes may respond differently to environmental change. Heatwaves, fires and reduced rainfall are predicted to increase in frequency and intensity in south-eastern Australia. It is not clear how soil respiration processes will respond to this changing climate and the implications for Australia's forest carbon balance. Soil respiration has been measured under reduced rainfall treatments and control plots using closed-dynamic manual chambers linked to a Cavity Ring-Down Spectrometer in a temperate dry eucalypt forest. In addition soil greenhouse gas dynamics are monitored using automated chambers linked to a Fourier Transform Infra Red spectrometer. Forest net carbon exchange is determined using eddy-covariance measurements as part of a long-term ecosystem research project. This presentation focuses on data collected using manual chambers where soil respiration and its component heterotrophic (root exclusion), autotrophic (indirectly) and litter decomposition (indirectly) fluxes have been measured for 1.5 years with regards to their 1) spatial variability, 2) environmental drivers and 3) response to reduced rainfall (40%). First results show total soil respiration (TSR) decreased on average by 16% under reduced rainfall treatment and varied with season according to soil temperature with lowest rates during winter/autumn and highest rates during spring/summer. The contribution of heterotrophic respiration (RH) was on average 28% and

  15. Uncoupling of microbial community structure and function in decomposing litter across beech forest ecosystems in Central Europe

    PubMed Central

    Purahong, Witoon; Schloter, Michael; Pecyna, Marek J.; Kapturska, Danuta; Däumlich, Veronika; Mital, Sanchit; Buscot, François; Hofrichter, Martin; Gutknecht, Jessica L. M.; Krüger, Dirk

    2014-01-01

    The widespread paradigm in ecology that community structure determines function has recently been challenged by the high complexity of microbial communities. Here, we investigate the patterns of and connections between microbial community structure and microbially-mediated ecological function across different forest management practices and temporal changes in leaf litter across beech forest ecosystems in Central Europe. Our results clearly indicate distinct pattern of microbial community structure in response to forest management and time. However, those patterns were not reflected when potential enzymatic activities of microbes were measured. We postulate that in our forest ecosystems, a disconnect between microbial community structure and function may be present due to differences between the drivers of microbial growth and those of microbial function. PMID:25388562

  16. Uncoupling of microbial community structure and function in decomposing litter across beech forest ecosystems in Central Europe.

    PubMed

    Purahong, Witoon; Schloter, Michael; Pecyna, Marek J; Kapturska, Danuta; Däumlich, Veronika; Mital, Sanchit; Buscot, François; Hofrichter, Martin; Gutknecht, Jessica L M; Krüger, Dirk

    2014-01-01

    The widespread paradigm in ecology that community structure determines function has recently been challenged by the high complexity of microbial communities. Here, we investigate the patterns of and connections between microbial community structure and microbially-mediated ecological function across different forest management practices and temporal changes in leaf litter across beech forest ecosystems in Central Europe. Our results clearly indicate distinct pattern of microbial community structure in response to forest management and time. However, those patterns were not reflected when potential enzymatic activities of microbes were measured. We postulate that in our forest ecosystems, a disconnect between microbial community structure and function may be present due to differences between the drivers of microbial growth and those of microbial function. PMID:25388562

  17. Lessons from community-based payment for ecosystem service schemes: from forests to rangelands.

    PubMed

    Dougill, Andrew J; Stringer, Lindsay C; Leventon, Julia; Riddell, Mike; Rueff, Henri; Spracklen, Dominick V; Butt, Edward

    2012-11-19

    Climate finance investments and international policy are driving new community-based projects incorporating payments for ecosystem services (PES) to simultaneously store carbon and generate livelihood benefits. Most community-based PES (CB-PES) research focuses on forest areas. Rangelands, which store globally significant quantities of carbon and support many of the world's poor, have seen little CB-PES research attention, despite benefitting from several decades of community-based natural resource management (CBNRM) projects. Lessons from CBNRM suggest institutional considerations are vital in underpinning the design and implementation of successful community projects. This study uses documentary analysis to explore the institutional characteristics of three African community-based forest projects that seek to deliver carbon-storage and poverty-reduction benefits. Strong existing local institutions, clear land tenure, community control over land management decision-making and up-front, flexible payment schemes are found to be vital. Additionally, we undertake a global review of rangeland CBNRM literature and identify that alongside the lessons learned from forest projects, rangeland CB-PES project design requires specific consideration of project boundaries, benefit distribution, capacity building for community monitoring of carbon storage together with awareness-raising using decision-support tools to display the benefits of carbon-friendly land management. We highlight that institutional analyses must be undertaken alongside improved scientific studies of the carbon cycle to enable links to payment schemes, and for them to contribute to poverty alleviation in rangelands. PMID:23045714

  18. Hybrid MCDA Methods to Integrate Multiple Ecosystem Services in Forest Management Planning: A Critical Review

    NASA Astrophysics Data System (ADS)

    Uhde, Britta; Andreas Hahn, W.; Griess, Verena C.; Knoke, Thomas

    2015-08-01

    Multi-criteria decision analysis (MCDA) is a decision aid frequently used in the field of forest management planning. It includes the evaluation of multiple criteria such as the production of timber and non-timber forest products and tangible as well as intangible values of ecosystem services (ES). Hence, it is beneficial compared to those methods that take a purely financial perspective. Accordingly, MCDA methods are increasingly popular in the wide field of sustainability assessment. Hybrid approaches allow aggregating MCDA and, potentially, other decision-making techniques to make use of their individual benefits and leading to a more holistic view of the actual consequences that come with certain decisions. This review is providing a comprehensive overview of hybrid approaches that are used in forest management planning. Today, the scientific world is facing increasing challenges regarding the evaluation of ES and the trade-offs between them, for example between provisioning and regulating services. As the preferences of multiple stakeholders are essential to improve the decision process in multi-purpose forestry, participatory and hybrid approaches turn out to be of particular importance. Accordingly, hybrid methods show great potential for becoming most relevant in future decision making. Based on the review presented here, the development of models for the use in planning processes should focus on participatory modeling and the consideration of uncertainty regarding available information.

  19. Toward an integrated classification of ecosystems: Defining opportunities for managing fish and forest health

    SciTech Connect

    Rieman, B.E.; Lee, D.C.; Thurow, R.F.; Hessburg, P.F.; Sedell, J.R.

    2000-04-01

    Many of the aquatic and terrestrial ecosystems of the Pacific Northwest United States have been simplified and degraded in part through past land-management activities. Recent listings of fishes under the Endangered Species Act and major new initiatives for the restoration of forest health have precipitated contentious debate among managers and conservation interests in the region. Because aggressive management activities proposed for forest restoration may directly affect watershed processes and functions, the goals of aquatic and terrestrial conservation and restoration are generally viewed as in conflict. The inextricable links in ecological processes and functions, however, suggest the two perspectives should really represent elements of the same problem; that of conserving and restoring more functional landscapes. The authors used recent information on the status and distribution of forest and fish communities to classify river sub basins across the region and explore the potential conflict and opportunity for a more integrated view of management. The authors classification indicated that there are often common trends in terrestrial and aquatic communities that highlight areas of potential convergence in management goals. Regions where patterns diverge may emphasize the need to particular care and investment in detailed risk analyses. Their spatially explicit classification of sub basin conditions provides a mechanism for progress in three areas that the authors think is necessary for a more integrated approach to management: (1) communication among disciplines; (2) effective prioritization of limited conservation and restoration resources; and (3) a framework for experimentation and demonstration of commitment and untested restoration techniques.

  20. Use of calcium/aluminum ratios as indicators of stress in forest ecosystems

    SciTech Connect

    Cronan, C.S.; Grigal, D.F.

    1995-03-01

    The calcium/aluminum (Ca/Al) molar ratio of the soil solution provides a valuable measurement endpoint or ecological indicator for identification of approximate thresholds beyond which the risk of forest damage from Al stress and nutrient imbalances increases. The Ca/Al ratio can also be used as an indicator to assess forest ecosystem changes over time in response to acidic deposition, forest harvesting, or other processes contributing to acid soil infertility. Based on a critical review of literature on Al stress, we estimate that there is a 50:50 risk of adverse impacts on tree growth or nutrition when the soil solution Ca/Al ratio is as low as 1.0, a 75% risk when the soil solution ratio is as low as 0.5, and nearly a 100% risk when the soil solution Ca/Al molar ratio is as low as 0.2. The Ca/Al ratio of the soil solution can be corroborated with other complementary indices.

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