WorldWideScience

Sample records for forests carbon cycle

  1. Hyperdominance in Amazonian forest carbon cycling

    NARCIS (Netherlands)

    Fauset, S.; Arets, E.J.M.M.; Steege, ter H.; Pena Claros, M.; Poorter, L.; Levis, C.; Toledo, M.

    2015-01-01

    While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant’ species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem

  2. Hyperdominance in Amazonian forest carbon cycling

    Science.gov (United States)

    Fauset, Sophie; Johnson, Michelle O.; Gloor, Manuel; Baker, Timothy R.; Monteagudo M., Abel; Brienen, Roel J.W.; Feldpausch, Ted R.; Lopez-Gonzalez, Gabriela; Malhi, Yadvinder; ter Steege, Hans; Pitman, Nigel C.A.; Baraloto, Christopher; Engel, Julien; Pétronelli, Pascal; Andrade, Ana; Camargo, José Luís C.; Laurance, Susan G.W.; Laurance, William F.; Chave, Jerôme; Allie, Elodie; Vargas, Percy Núñez; Terborgh, John W.; Ruokolainen, Kalle; Silveira, Marcos; Aymard C., Gerardo A.; Arroyo, Luzmila; Bonal, Damien; Ramirez-Angulo, Hirma; Araujo-Murakami, Alejandro; Neill, David; Hérault, Bruno; Dourdain, Aurélie; Torres-Lezama, Armando; Marimon, Beatriz S.; Salomão, Rafael P.; Comiskey, James A.; Réjou-Méchain, Maxime; Toledo, Marisol; Licona, Juan Carlos; Alarcón, Alfredo; Prieto, Adriana; Rudas, Agustín; van der Meer, Peter J.; Killeen, Timothy J.; Marimon Junior, Ben-Hur; Poorter, Lourens; Boot, Rene G.A.; Stergios, Basil; Torre, Emilio Vilanova; Costa, Flávia R.C.; Levis, Carolina; Schietti, Juliana; Souza, Priscila; Groot, Nikée; Arets, Eric; Moscoso, Victor Chama; Castro, Wendeson; Coronado, Euridice N. Honorio; Peña-Claros, Marielos; Stahl, Clement; Barroso, Jorcely; Talbot, Joey; Vieira, Ima Célia Guimarães; van der Heijden, Geertje; Thomas, Raquel; Vos, Vincent A.; Almeida, Everton C.; Davila, Esteban Álvarez; Aragão, Luiz E.O.C.; Erwin, Terry L.; Morandi, Paulo S.; de Oliveira, Edmar Almeida; Valadão, Marco B.X.; Zagt, Roderick J.; van der Hout, Peter; Loayza, Patricia Alvarez; Pipoly, John J.; Wang, Ophelia; Alexiades, Miguel; Cerón, Carlos E.; Huamantupa-Chuquimaco, Isau; Di Fiore, Anthony; Peacock, Julie; Camacho, Nadir C. Pallqui; Umetsu, Ricardo K.; de Camargo, Plínio Barbosa; Burnham, Robyn J.; Herrera, Rafael; Quesada, Carlos A.; Stropp, Juliana; Vieira, Simone A.; Steininger, Marc; Rodríguez, Carlos Reynel; Restrepo, Zorayda; Muelbert, Adriane Esquivel; Lewis, Simon L.; Pickavance, Georgia C.; Phillips, Oliver L.

    2015-01-01

    While Amazonian forests are extraordinarily diverse, the abundance of trees is skewed strongly towards relatively few ‘hyperdominant' species. In addition to their diversity, Amazonian trees are a key component of the global carbon cycle, assimilating and storing more carbon than any other ecosystem on Earth. Here we ask, using a unique data set of 530 forest plots, if the functions of storing and producing woody carbon are concentrated in a small number of tree species, whether the most abundant species also dominate carbon cycling, and whether dominant species are characterized by specific functional traits. We find that dominance of forest function is even more concentrated in a few species than is dominance of tree abundance, with only ≈1% of Amazon tree species responsible for 50% of carbon storage and productivity. Although those species that contribute most to biomass and productivity are often abundant, species maximum size is also influential, while the identity and ranking of dominant species varies by function and by region. PMID:25919449

  3. Trailblazing the Carbon Cycle of Tropical Forests from Puerto Rico

    Directory of Open Access Journals (Sweden)

    Sandra Brown

    2017-03-01

    Full Text Available We review the literature that led to clarifying the role of tropical forests in the global carbon cycle from a time when they were considered sources of atmospheric carbon to the time when they were found to be atmospheric carbon sinks. This literature originates from work conducted by US Forest Service scientists in Puerto Rico and their collaborators. It involves the classification of forests by life zones, estimation of carbon density by forest type, assessing carbon storage changes with ecological succession and land use/land cover type, describing the details of the carbon cycle of forests at stand and landscape levels, assessing global land cover by forest type and the complexity of land use change in tropical regions, and assessing the ecological fluxes and storages that contribute to net carbon accumulation in tropical forests. We also review recent work that couples field inventory data, remote sensing technology such as LIDAR, and GIS analysis in order to more accurately determine the role of tropical forests in the global carbon cycle and point out new avenues of carbon research that address the responses of tropical forests to environmental change.

  4. Hotspots of the European forests carbon cycle

    NARCIS (Netherlands)

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

    2008-01-01

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

  5. Forest defoliator pests alter carbon and nitrogen cycles

    Science.gov (United States)

    Grüning, Maren; Simon, Judy; Reinhardt, Annett-Barbara; Lamersdorf, Norbert; Thies, Carsten

    2016-01-01

    Climate change may foster pest epidemics in forests, and thereby the fluxes of elements that are indicators of ecosystem functioning. We examined compounds of carbon (C) and nitrogen (N) in insect faeces, leaf litter, throughfall and analysed the soils of deciduous oak forests (Quercus petraea L.) that were heavily infested by the leaf herbivores winter moth (Operophtera brumata L.) and mottled umber (Erannis defoliaria L.). In infested forests, total net canopy-to-soil fluxes of C and N deriving from insect faeces, leaf litter and throughfall were 30- and 18-fold higher compared with uninfested oak forests, with 4333 kg C ha−1 and 319 kg N ha−1, respectively, during a pest outbreak over 3 years. In infested forests, C and N levels in soil solutions were enhanced and C/N ratios in humus layers were reduced indicating an extended canopy-to-soil element pathway compared with the non-infested forests. In a microcosm incubation experiment, soil treatments with insect faeces showed 16-fold higher fluxes of carbon dioxide and 10-fold higher fluxes of dissolved organic carbon compared with soil treatments without added insect faeces (control). Thus, the deposition of high rates of nitrogen and rapidly decomposable carbon compounds in the course of forest pest epidemics appears to stimulate soil microbial activity (i.e. heterotrophic respiration), and therefore, may represent an important mechanism by which climate change can initiate a carbon cycle feedback. PMID:27853551

  6. Projections of forest contributions to global carbon cycles

    Science.gov (United States)

    Michael E. Goerndt; Stephen R. Shifley; Patrick D. Miles; Dave Wear; Francisco X. Aguilar

    2016-01-01

    Forests cover 42 percent of the Northern United States, and collectively they store 13 billion tons of carbon in live trees (29 percent), roots (6 percent), forest floor (9 percent), dead trees (6 percent), and soils (50 percent). About half the biomass of a live tree (dry weight basis) is sequestered carbon (Woodall et al. 2011) - not the largest but the most dynamic...

  7. China’s Forests and Their Impact on Global Carbon Cycle

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Forests have multiple benefits and functions, including mitigation of climate change. The impacts of forests on the global carbon cycle include forests as carbon sinks, wood-based products as carbon sinks, bio-energy, and production and use of non-timber products. In the past decades, forest cover of China has increased from 8.6% to 18.21% by large-scale afforestation and conversion of cropland into forests. Forest biomass carbon (C) stock increased from 4.3 Pg C (1 Pg C = 1 015 g C) in the early 1980s to 5...

  8. Challenges for measuring and modeling carbon cycling in degraded tropical forests: Examples from the Brazilian Amazon

    Science.gov (United States)

    Keller, M. M.; Longo, M.; Morton, D. C.; Leitold, V.; Pinagé, E. R.; dos-Santos, M. N.; Scaranello, M. A., Sr.

    2016-12-01

    Deforestation has cleared almost 20% of the forest in the Brazilian Amazon region. Logging, and understory forest fires may have degraded a similar area of forest. Despite the significant reduction of deforestation over the past decade, forest degradation through logging and understory fire continues to affect carbon stocks and fluxes. Recent studies using atmospheric data show that uptake by Amazon ecosystems balances or exceeds the carbon dioxide release by deforestation in normal (non-drought) years. However, old growth forest carbon dioxide uptake appears to be declining. Therefore, regeneration of degraded and secondary forests may be playing an ever more important role in the carbon balance of the world's largest extent of tropical forest. There are multiple challenges for understanding the role of degraded forests in regional and global carbon cycling. First, to date, no reliable estimates of the total area of degraded forest or the carbon losses associated with degradation exist in the Amazon. Remote sensing detection of forest degradation is far more difficult than detection of deforestation because changes in canopy characteristics are subtler. Second, forests may be subject to multiple degradation events and forest structure and species composition resulting from degradation is highly variable. Third, the structure of forests that result from degradation can be radically different from more commonly studied old-growth and secondary forests. Finally, there are few measurements that quantify degraded forest function. We will demonstrate pathways to resolving these challenges including (i) multi-temporal remote sensing studies of forest degradation dynamics on the Amazon frontier; (ii) forest structure and biomass estimates using airborne lidar data; (iii) changes in species composition based on forest inventory; and (iv) approaches for incorporating lidar data into a demographic modeling framework.

  9. Effects of climate variability and functional changes on carbon cycling in a temperate deciduous forest

    DEFF Research Database (Denmark)

    Wu, Jian

    Temperate forests are globally important carbon (C) stocks and sinks. A decadal (1997-2009) trend of increasing C uptake has been observed in an intensively studied temperate deciduous forest, Sorø (Zealand, Denmark). This gave the impetus to investigate the factors controlling the C cycling...... calculated ECB components based on mass balance equations, a synthesis of the carbon cycling was performed. The results showed that this temperature deciduous forest was moderately productive with both high rates of gross primary production and ecosystem respiration. Approximately 62% of the gross...... of studies in order to provide a complete assessment of the carbon storage and allocation within the ecosystem and clarify the mechanisms responsible for the observed variability and trend in the ecosystem C fluxes. Combining all independently estimated ecosystem carbon budget (ECB) datasets and other...

  10. Carbon Cycling, Climate Regulation, and Disturbances in Canadian Forests: Scientific Principles for Management

    Directory of Open Access Journals (Sweden)

    Jean-Sébastien Landry

    2015-01-01

    Full Text Available Canadian forests are often perceived as pristine and among the last remaining wilderness, but the majority of them are officially managed and undergo direct land use, mostly for wood harvest. This land use has modified their functions and properties, often inadvertently (e.g., age structure but sometimes purposefully (e.g., fire suppression. Based on a review of the literature pertaining to carbon cycling, climate regulation, and disturbances from logging, fire, and insect outbreaks, we propose five scientific principles relevant for Canadian managed forests. Among these, a principle we wish to highlight is the need to properly account for the management-related fossil fuel emissions, because they will affect the global carbon cycle and climate for millennia unless massive atmospheric carbon dioxide removal becomes a reality. We also use these five principles to address questions of current interest to research scientists, forest managers, and policy makers. Our review focusses on total ecosystem carbon storage and various mechanisms through which forests affect climate, in particular albedo and aerosols forcings—including how disturbances influence all these elements—but also touches on other ecosystem goods and services. Our review underscores the importance of conducting >100-year time horizon studies of carbon cycling, climate regulation, and disturbances in Canadian managed forests.

  11. Role of temperate zone forests in the world carbon cycle: problem definition and research needs

    Energy Technology Data Exchange (ETDEWEB)

    Armentano, T.V.; Hett, J. (eds.)

    1979-01-01

    The proceedings of a workshop on carbon uptake and losses from temperate zone forests are presented. The goals of the workshop were to analyze existing data on growth and utilization of the temperate zone forest carbon pool and to identify further research needs in relation to the role of temperate forests in the global carbon cycle. Total standing stock and growth recovery transients were examined for most of the temperate region over a period from pre-settlement times to the present, with emphasis on the last three decades. Because of data availability, certain regions and topics were covered more in detail than others. Forest inventory data from most of the commercial timberlands of the north temperate zone suggest these forests have functioned over the past several decades as an annual sink for about 10/sup 9/ metric tons of carbon. Thus, net growth of these forests has withdrawn carbon from the atmosphere at a rate equivalent, approximately, to 50% of the annual rise in atmospheric carbon. Various data inadequacies make this estimate probably no more precise than plus or minus half of the value. Analysis of growth and vegetation changes in New England and the southeastern United States shows that forest biomass has partly recovered since extensive clearing took place in the 18th and 19th centuries. This regrowth represents a net withdrawal of carbon (carbon sink) from the atmosphere in recent decades, although the difference in pool size between present and original forests means that, in the longer term, the two regions have functioned as carbon sources.

  12. Subalpine Forest Carbon Cycling Short- and Long-Term Influence ofClimate and Species

    Energy Technology Data Exchange (ETDEWEB)

    Kueppers, L.; Harte, J.

    2005-08-23

    Ecosystem carbon cycle feedbacks to climate change comprise one of the largest remaining sources of uncertainty in global model predictions of future climate. Both direct climate effects on carbon cycling and indirect effects via climate-induced shifts in species composition may alter ecosystem carbon balance over the long term. In the short term, climate effects on carbon cycling may be mediated by ecosystem species composition. We used an elevational climate and tree species composition gradient in Rocky Mountain subalpine forest to quantify the sensitivity of all major ecosystem carbon stocks and fluxes to these factors. The climate sensitivities of carbon fluxes were species-specific in the cases of relative above ground productivity and litter decomposition, whereas the climate sensitivity of dead wood decay did not differ between species, and total annual soil CO2 flux showed no strong climate trend. Lodge pole pine relative productivity increased with warmer temperatures and earlier snowmelt, while Engelmann spruce relative productivity was insensitive to climate variables. Engelmann spruce needle decomposition decreased linearly with increasing temperature(decreasing litter moisture), while lodgepole pine and subalpine fir needle decay showed a hump-shaped temperature response. We also found that total ecosystem carbon declined by 50 percent with a 2.88C increase in mean annual temperature and a concurrent 63 percent decrease ingrowing season soil moisture, primarily due to large declines in mineral soil and dead wood carbon. We detected no independent effect of species composition on ecosystem C stocks. Overall, our carbon flux results suggest that, in the short term, any change in subalpine forest net carbon balance will depend on the specific climate scenario and spatial distribution of tree species. Over the long term, our carbon stock results suggest that with regional warming and drying, Rocky Mountain subalpine forest will be a net source of carbon

  13. Variation in phenolic root exudates and rhizosphere carbon cycling among tree species in temperate forest ecosystems

    Science.gov (United States)

    Zwetsloot, Marie; Bauerle, Taryn; Kessler, André; Wickings, Kyle

    2017-04-01

    Temperate forest tree species composition has been highly dynamic over the past few centuries and is expected to only further change under current climate change predictions. While aboveground changes in forest biodiversity have been widely studied, the impacts on belowground processes are far more challenging to measure. In particular, root exudation - the process through which roots release organic and inorganic compounds into the rhizosphere - has received little scientific attention yet may be the key to understanding root-facilitated carbon cycling in temperate forest ecosystems. The aim of this study was to analyze the extent by which tree species' variation in phenolic root exudate profiles influences soil carbon cycling in temperate forest ecosystems. In order to answer this question, we grew six temperate forest tree species in a greenhouse including Acer saccharum, Alnus rugosa, Fagus grandifolia, Picea abies, Pinus strobus, and Quercus rubra. To collect root exudates, trees were transferred to hydroponic growing systems for one week and then exposed to cellulose acetate strips in individual 800 mL jars with a sterile solution for 24 hours. We analyzed the methanol-extracted root exudates for phenolic composition with high-performance liquid chromatography (HPLC) and determined species differences in phenolic abundance, diversity and compound classes. This information was used to design the subsequent soil incubation study in which we tested the effect of different phenolic compound classes on rhizosphere carbon cycling using potassium hydroxide (KOH) traps to capture soil CO2 emissions. Our findings show that tree species show high variation in phenolic root exudate patterns and that these differences can significantly influence soil CO2 fluxes. These results stress the importance of linking belowground plant traits to ecosystem functioning. Moreover, this study highlights the need for research on root and rhizosphere processes in order to improve

  14. Alteration of forest succession and carbon cycling under elevated CO2.

    Science.gov (United States)

    Miller, Adam D; Dietze, Michael C; DeLucia, Evan H; Anderson-Teixeira, Kristina J

    2016-01-01

    Regenerating forests influence the global carbon (C) cycle, and understanding how climate change will affect patterns of regeneration and C storage is necessary to predict the rate of atmospheric carbon dioxide (CO2 ) increase in future decades. While experimental elevation of CO2 has revealed that young forests respond with increased productivity, there remains considerable uncertainty as to how the long-term dynamics of forest regrowth are shaped by elevated CO2 (eCO2 ). Here, we use the mechanistic size- and age- structured Ecosystem Demography model to investigate the effects of CO2 enrichment on forest regeneration, using data from the Duke Forest Free-Air Carbon dioxide Enrichment (FACE) experiment, a forest chronosequence, and an eddy-covariance tower for model parameterization and evaluation. We find that the dynamics of forest regeneration are accelerated, and stands consistently hit a variety of developmental benchmarks earlier under eCO2 . Because responses to eCO2 varied by plant functional type, successional pathways, and mature forest composition differed under eCO2 , with mid- and late-successional hardwood functional types experiencing greater increases in biomass compared to early-successional functional types and the pine canopy. Over the simulation period, eCO2 led to an increase in total ecosystem C storage of 9.7 Mg C ha(-1) . Model predictions of mature forest biomass and ecosystem-atmosphere exchange of CO2 and H2 O were sensitive to assumptions about nitrogen limitation; both the magnitude and persistence of the ecosystem response to eCO2 were reduced under N limitation. In summary, our simulations demonstrate that eCO2 can result in a general acceleration of forest regeneration while altering the course of successional change and having a lasting impact on forest ecosystems.

  15. To spatially explicitly quantify the indirect effect of disturbances on carbon cycle of Canada's forests

    Science.gov (United States)

    Chen, W.; Cihlar, J.; Wang, S.; Zhang, Q.; Ung, C.; Price, D.; Fernandes, R.; Fraser, R.

    2001-12-01

    Disturbances (i.e., fire, insects-induced mortality, and harvesting) affect the carbon cycle of forested ecosystems directly in the year of occurrence and indirectly in many years after. For example, forest fire directly releases a fraction of carbon in biomass and forest floor to the atmosphere. The carbon cycle is also affected indirectly by disturbances which set the disturbed stand to age zero. So far, most studies estimate the indirect effect of disturbances on carbon balance at regional to national scales by aggregated forests in a region or a country into a few units, and largely ignoring the effect of spatial heterogeneity of disturbances and environmental factors. Because the effects of disturbances and environmental factors are usually non-linear, ignoring their spatial heterogeneity may introduce large error in the carbon budget estimates. In order to reduce this potential large error, spatially explicit quantification of the indirect effect of disturbances are urgently needed. Spatially explicit estimates of carbon cycle at 1-km resolution also allow direct testing against field measurements, as well as provide essential information for sustainable development of natural resources. To spatially explicitly quantify the indirect effect of disturbances on carbon cycle, we need first to quantify how stand age affects NPP. Our early results indicated the effect of stand age on NPP is species and site quality dependent. Therefore, age-NPP relationships are needed for all major forest species to carry out the spatially explicitly quantification of indirect effect of disturbances. We will derive these age-NPP relationships using existing yield tables, biomass allometric equations, and recent data on fine root and foliage production. To apply these age-NPP relationships, we need geo-spatial information on species, age, and site quality. Several initiatives have been underway to develop these spatial data layers. Because the NPP derived using these age

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

    Science.gov (United States)

    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.

  17. Simulating Amazon forest carbon cycling using an individual- and trait-based model.

    Science.gov (United States)

    Fauset, S.; Fyllas, N.; Galbraith, D.; Christoffersen, B. O.; Baker, T. R.; Johnson, M. O.; Malhi, Y.; Phillips, O. L.; Lloyd, J.; Gloor, E. U.

    2014-12-01

    The Amazon forest, a regional and global regulator of climate and store of enormous biodiversity, is an incredibly complex ecosystem. Just one ha of forest can contain 300 different species of tree, with an estimated 16,000 tree species present in the region. Different tree species, and even different individuals of a species, vary in their functional traits, influencing how they behave in response to the environment. Dynamic global vegetation models (DGVMs) are commonly used to simulate the response of the Amazon forest to global environmental change. Yet, such DGVMs typically use a plant functional type (PFT) approach where variation between individuals and species are not represented, which inherently limits the range of outcomes for Amazonia under climate change. Here, we report on recent advances in an alternative approach to tropical forest modeling that represents the size structure and variation of traits within a community, which we term the Trait-based Forest Simulator (TFS). As originally proposed, TFS was strictly a steady-state model and here we present an extension of TFS which includes full forest dynamics, and has been evaluated with data collected from intensive carbon cycling inventory plots from the GEM (Global Ecosystems Monitoring) network. Specifically, we compare the model output to stand-level data on productivity and respiration of the canopy, stems and roots. The model development process has highlighted ecological tradeoffs that are necessary to integrate into trait-based models, such as a shorter leaf lifetime with a lower leaf mass per area. The adapted TFS model simulates carbon cycling in forest plots, including variation in productivity between sites. These results lend confidence to the ability of next-generation vegetation models to accurately simulate forest sensitivity to future changes.

  18. Carbon Dioxide Effects Research and Assessment Program. The role of tropical forests on the world carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Brown, S.; Lugo, A. E.; Liegel, B. [eds.

    1980-08-01

    Tropical forests constitute about half of the world's forest and are characterized by rapid rates of organic matter turnover and high storages of organic matter. Tropical forests are considered to be one of the most significant terrestrial elements in the equation that balances the carbon cycle of the world. As discussed in the paper by Tosi, tropical and subtropical latitudes are more complex in terms of climate and vegetation composition than temperate and boreal latitudes. The implications of the complexity of the tropics and the disregard of this complexity by many scientists is made evident in the paper by Brown and Lugo which shows that biomass estimates for tropical ecosystems have been overestimated by at least 100%. The paper by Brown shows that that rates of succession in the tropics are extremely rapid in terms of the ability of moist and wet forests to accumulate organic matter. Yet, in arid tropical Life Zones succession is slow. This leads to the idea that the question of whether tropical forests are sinks or sources of carbon must be analyzed in relation to Life Zones and to intensities of human activity in these Zones. The paper by Lugo presents conceptual models to illustrate this point and the paper by Tosi shows how land uses in the tropics also correspond to Life Zone characteristics. The ultimate significance of land use to the question of the carbon balance in a large region is addressed in the paper by Detwiler and Hall.

  19. Dissolved Organic Carbon Cycling in Forested Watersheds: A Carbon Isotope Approach

    Science.gov (United States)

    Schiff, S. L.; Aravena, R.; Trumbore, S. E.; Dillon, P. J.

    1990-12-01

    Dissolved organic carbon (DOC) is important in the acid-base chemistry of acid-sensitive freshwater systems; in the complexation, mobility, persistence, and toxicity of metals and other pollutants; and in lake carbon metabolism. Carbon isotopes (13C and 14C) are used to study the origin, transport, and fate of DOC in a softwater catchment in central Ontario. Precipitation, soil percolates, groundwaters, stream, beaver pond, and lake waters, and lake sediment pore water were characterized chemically and isotopically. In addition to total DOC, isotopic measurements were made on the humic and fulvic DOC fractions. The lake is a net sink for DOC. Δ14C results indicate that the turnover time of most of the DOC in streams, lakes, and wetlands is fast, less than 40 years, and on the same time scale as changes in acidic deposition. DOC in groundwaters is composed of older carbon than surface waters, indicating extensive cycling of DOC in the upper soil zone or aquifer.

  20. Carbon footprint of forest and tree utilization technologies in life cycle approach

    Science.gov (United States)

    Polgár, András; Pécsinger, Judit

    2017-04-01

    In our research project a suitable method has been developed related the technological aspect of the environmental assessment of land use changes caused by climate change. We have prepared an eco-balance (environmental inventory) to the environmental effects classification in life-cycle approach in connection with the typical agricultural / forest and tree utilization technologies. The use of balances and environmental classification makes possible to compare land-use technologies and their environmental effects per common functional unit. In order to test our environmental analysis model, we carried out surveys in sample of forest stands. We set up an eco-balance of the working systems of intermediate cutting and final harvest in the stands of beech, oak, spruce, acacia, poplar and short rotation energy plantations (willow, poplar). We set up the life-cycle plan of the surveyed working systems by using the GaBi 6.0 Professional software and carried out midpoint and endpoint impact assessment. Out of the results, we applied the values of CML 2001 - Global Warming Potential (GWP 100 years) [kg CO2-Equiv.] and Eco-Indicator 99 - Human health, Climate Change [DALY]. On the basis of the values we set up a ranking of technology. By this, we received the environmental impact classification of the technologies based on carbon footprint. The working systems had the greatest impact on global warming (GWP 100 years) throughout their whole life cycle. This is explained by the amount of carbon dioxide releasing to the atmosphere resulting from the fuel of the technologies. Abiotic depletion (ADP foss) and marine aquatic ecotoxicity (MAETP) emerged also as significant impact categories. These impact categories can be explained by the share of input of fuel and lube. On the basis of the most significant environmental impact category (carbon footprint), we perform the relative life cycle contribution and ranking of each technologies. The technological life cycle stages examined

  1. The human footprint in the carbon cycle of temperate and boreal forests

    Science.gov (United States)

    Magnani, Federico; Mencuccini, Maurizio; Borghetti, Marco; Berbigier, Paul; Berninger, Frank; Delzon, Sylvain; Grelle, Achim; Hari, Pertti; Jarvis, Paul G.; Kolari, Pasi; Kowalski, Andrew S.; Lankreijer, Harry; Law, Beverly E.; Lindroth, Anders; Loustau, Denis; Manca, Giovanni; Moncrieff, John B.; Rayment, Mark; Tedeschi, Vanessa; Valentini, Riccardo; Grace, John

    2007-06-01

    Temperate and boreal forests in the Northern Hemisphere cover an area of about 2×107square kilometres and act as a substantial carbon sink (0.6-0.7 petagrams of carbon per year). Although forest expansion following agricultural abandonment is certainly responsible for an important fraction of this carbon sink activity, the additional effects on the carbon balance of established forests of increased atmospheric carbon dioxide, increasing temperatures, changes in management practices and nitrogen deposition are difficult to disentangle, despite an extensive network of measurement stations. The relevance of this measurement effort has also been questioned, because spot measurements fail to take into account the role of disturbances, either natural (fire, pests, windstorms) or anthropogenic (forest harvesting). Here we show that the temporal dynamics following stand-replacing disturbances do indeed account for a very large fraction of the overall variability in forest carbon sequestration. After the confounding effects of disturbance have been factored out, however, forest net carbon sequestration is found to be overwhelmingly driven by nitrogen deposition, largely the result of anthropogenic activities. The effect is always positive over the range of nitrogen deposition covered by currently available data sets, casting doubts on the risk of widespread ecosystem nitrogen saturation under natural conditions. The results demonstrate that mankind is ultimately controlling the carbon balance of temperate and boreal forests, either directly (through forest management) or indirectly (through nitrogen deposition).

  2. Translating Forest Change to Carbon Emissions and Removals By Linking Disturbance Products, Biomass Maps, and Carbon Cycle Modeling in a Comprehensive Carbon Monitoring Framework for the Conterminous US Forests

    Science.gov (United States)

    Williams, C. A.; Gu, H.

    2016-12-01

    Protecting forest carbon stores and uptake is central to national and international policies aimed at mitigating climate change. The success of such polices relies on high quality, accurate reporting (Tier 3) that earns the greatest financial value of carbon credits and hence incentivizes forest conservation and protection. Methods for Tier 3 Measuring, Reporting, and Verification (MRV) are still in development, generally involving some combination of direct remote sensing, ground based inventorying, and computer modeling, but have tended to emphasize assessments of live aboveground carbon stocks with a less clear connection to the real target of MRV which is carbon emissions and removals. Most existing methods are also ambiguous as to the mechanisms that underlie carbon accumulation, and any have limited capacity for forecasting carbon dynamics over time. This paper reports on the design and implementation of a new method for Tier 3 MRV, decision support, and forecasting that is being applied to assess forest carbon dynamics across the conterminous US. The method involves parameterization of a carbon cycle model (CASA) to match yield data from the US forest inventory (FIA). A range of disturbance types and severities are imposed in the model to estimate resulting carbon emissions, carbon uptake, and carbon stock changes post-disturbance. Resulting trajectories are then applied to landscapes at the 30-m pixel level based on two remote-sensing based data products. One documents the year, type, and severity of disturbance in recent decades. The second documents aboveground biomass which is used to estimate time since disturbance and associated carbon fluxes and stocks. Results will highlight high-resolution (30 m) annual carbon stocks and fluxes from 1990 to 2010 for select regions of interest across the US. Spatial analyses reveal regional patterns in US forest carbon stocks and fluxes as they respond to forest types, climate, and disturbances. Temporal analyses

  3. Effects of climate variability and functional changes on carbon cycling in a temperate deciduous forest

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jian

    2013-03-15

    Temperate forests are globally important carbon (C) stocks and sinks. A decadal (1997-2009) trend of increasing C uptake has been observed in an intensively studied temperate deciduous forest, Soroe (Zealand, Denmark). This gave the impetus to investigate the factors controlling the C cycling and the fundamental processes at work in this type of ecosystem. The major objectives of this study were to (1) evaluate to what extent and at what temporal scales, direct climatic variability and functional changes (e.g. changes in the structure or physiological properties) regulate the interannual variability (IAV) in the ecosystem C balance; (2) provide a synthesis of the ecosystem C budget at this site and (3) investigate whether terrestrial ecosystem models can dynamically simulate the trend of increasing C uptake. Data driven analysis, semi-empirical and process-based modelling experiments were performed in a series of studies in order to provide a complete assessment of the carbon storage and allocation within the ecosystem and clarify the mechanisms responsible for the observed variability and trend in the ecosystem C fluxes. Combining all independently estimated ecosystem carbon budget (ECB) datasets and other calculated ECB components based on mass balance equations, a synthesis of the carbon cycling was performed. The results showed that this temperature deciduous forest was moderately productive with both high rates of gross primary production and ecosystem respiration. Approximately 62% of the gross assimilated carbon was respired by the living plants, while 21% was contributed to the soil as litter production, the latter balancing the total heterotrophic respiration. The remaining 17% was either stored in the plants (mainly as aboveground biomass) or removed from the system as wood production. In general, the ECB component datasets were consistent after the cross-checking. This, together with their characterized uncertainties, can be used in model data fusion

  4. Biogeographic variation in evergreen conifer needle longevity and impacts on boreal forest carbon cycle projections.

    Science.gov (United States)

    Reich, Peter B; Rich, Roy L; Lu, Xingjie; Wang, Ying-Ping; Oleksyn, Jacek

    2014-09-23

    Leaf life span is an important plant trait associated with interspecific variation in leaf, organismal, and ecosystem processes. We hypothesized that intraspecific variation in gymnosperm needle traits with latitude reflects both selection and acclimation for traits adaptive to the associated temperature and moisture gradient. This hypothesis was supported, because across 127 sites along a 2,160-km gradient in North America individuals of Picea glauca, Picea mariana, Pinus banksiana, and Abies balsamea had longer needle life span and lower tissue nitrogen concentration with decreasing mean annual temperature. Similar patterns were noted for Pinus sylvestris across a north-south gradient in Europe. These differences highlight needle longevity as an adaptive feature important to ecological success of boreal conifers across broad climatic ranges. Additionally, differences in leaf life span directly affect annual foliage turnover rate, which along with needle physiology partially regulates carbon cycling through effects on gross primary production and net canopy carbon export. However, most, if not all, global land surface models parameterize needle longevity of boreal evergreen forests as if it were a constant. We incorporated temperature-dependent needle longevity and %nitrogen, and biomass allocation, into a land surface model, Community Atmosphere Biosphere Land Exchange, to assess their impacts on carbon cycling processes. Incorporating realistic parameterization of these variables improved predictions of canopy leaf area index and gross primary production compared with observations from flux sites. Finally, increasingly low foliage turnover and biomass fraction toward the cold far north indicate that a surprisingly small fraction of new biomass is allocated to foliage under such conditions.

  5. An Invasive Grass Species Alters Carbon Cycling in Hawaiian Dry Forest

    Science.gov (United States)

    Litton, C. M.; Sandquist, D. R.; Cordell, S.

    2004-12-01

    At lower elevations on the leeward side of the island of Hawaii, remnant native forests are heavily invaded by an introduced African bunchgrass, Pennisetum setaceum (fountain grass). Our research is designed to determine the consequences of this invasion for carbon (C) cycling in Hawaiian dry forests. We examined above- and belowground C pools and fluxes in 400 m2 replicated forest plots (n = 4) with fountain grass (grass plots) and in areas where fountain grass had been removed for ˜3 years (removal plots). C pools were estimated with direct sampling and allometric equations developed in situ for the dominant tree species. Aboveground net primary productivity (ANPP) was estimated as aboveground biomass increment plus litterfall minus loss from mortality (trees) and with clip plots (grass and herbaceous species); total belowground carbon allocation (TBCA) was estimated using a conservation of mass, C balance approach. Our results indicate that the invasion of a non-native grass in this ecosystem has considerable impacts on both C pools and fluxes. Aboveground, tree biomass did not differ between treatments (P = 0.57) but the presence of fountain grass led to a 7.5-fold increase in understory biomass in grass plots compared to removal plots (P < 0.01). Tree ANPP was significantly higher in removal plots for both foliage (0.10 and 0.06 kg C m-2 yr-1 for removal and grass plots, respectively; P = 0.02) and wood (0.13 and 0.05 kg C m-2 yr-1 for removal and grass plots, respectively; P < 0.01). However, grass ANPP was ˜35% greater than tree foliage productivity in grass plots. Despite this added foliar productivity, total ANPP (Tree + Grass ANPP) was significantly higher in removal plots (P = 0.04). Belowground, grass plots exhibited higher rates of soil-surface CO2 efflux (1.09 and 1.38 kg C m-2 yr-1 for removal and grass plots, respectively; P = 0.03 ). Likewise, TBCA was significantly higher in grass plots (1.21 kg C m-2 yr-1) than in removal plots (0.97 kg C m-2

  6. Forests and water cycle

    Directory of Open Access Journals (Sweden)

    Iovino F

    2009-06-01

    Full Text Available Based on a comprehensive literature analysis, a review on factors that control water cycle and water use in Mediterranean forest ecosystems is presented, including environmental variables and silvicultural treatments. This important issue is considered in the perspective of sustainable forest management of Mediterranean forests, with special regard to crucial environmental hazards such as forest fires and desertification risks related to climate change.

  7. Comparing Life-Cycle Carbon and Energy Impacts for Biofuel, Wood Product, and Forest Management

    Science.gov (United States)

    Bruce Lippke; Richard Gustafson; Richard Venditti; Philip Steele; Timothy A. Volk; Elaine Oneil; Leonard Johnson; Maureen E. Puettmann; Kenneth Skog

    2012-01-01

    The different uses of wood result in a hierarchy of carbon and energy impacts that can be characterized by their efficiency in displacing carbon emissions and/or in displacing fossil energy imports, both being current national objectives. When waste wood is used for biofuels (forest or mill residuals and thinnings) fossil fuels and their emissions are reduced without...

  8. Dissolved Organic Carbon Cycling and Transformation Dynamics in A Northern Forested Peatland

    Science.gov (United States)

    Tfaily, M. M.; Lin, X.; Chanton, P. R.; Steinweg, J.; Esson, K.; Kostka, J. E.; Cooper, W. T.; Schadt, C. W.; Hanson, P. J.; Chanton, J.

    2013-12-01

    Peatlands sequester one-third of all soil carbon and currently act as major sinks of atmospheric carbon dioxide. The ability to predict or simulate the fate of stored carbon in response to climatic disruption remains hampered by our limited understanding of the controls of carbon turnover and the composition and functioning of peatland microbial communities. A combination of advanced analytical chemistry and microbiology approaches revealed that organic matter reactivity and microbial community dynamics were closely coupled in an extensive field dataset compiled at the S1 bog site established for the SPRUCE program, Marcell Experimental Forest (MEF). The molecular composition and decomposition pathways of dissolved organic carbon (DOC) were contrasted using parallel factor (PARAFAC)-modeled excitation emission fluorescence spectroscopy (EEMS) and FT-ICR MS. The specific UV absorbance (SUVA) at 254 nm was calculated as an indicator of aromaticity. Fluorescence intensity ratios (BIX and FI) were used to infer the relative contributions from solid phase decomposition and microbial production. Distributions of bulk DOC, its stable (δ13C) and radioactive (Δ14C) isotopic composition were also utilized to infer information on its dynamics and transformation processes. Strong vertical stratification was observed in organic matter composition, the distribution of mineralization products (CO2, CH4), respiration rates, and decomposition pathways, whereas smaller variations were observed between sites. A decline in the aromaticity of pore water DOC was accompanied by an increase in microbially-produced DOC. Solid phase peat, on the other hand, became more humified and highly aromatic with depth. These observations were consistent with radiocarbon data that showed that the radiocarbon signatures of microbial respiration products in peat porewaters more closely resemble those of DOC rather than solid peat, indicating that carbon from recent photosynthesis is fueling the

  9. Carbon cycling and net ecosystem production at an early stage of secondary succession in an abandoned coppice forest.

    Science.gov (United States)

    Ohtsuka, Toshiyuki; Shizu, Yoko; Nishiwaki, Ai; Yashiro, Yuichiro; Koizumi, Hiroshi

    2010-07-01

    Secondary mixed forests are one of the dominant forest cover types in human-dominated temperate regions. However, our understanding of how secondary succession affects carbon cycling and carbon sequestration in these ecosystems is limited. We studied carbon cycling and net ecosystem production (NEP) over 4 years (2004-2008) in a cool-temperate deciduous forest at an early stage of secondary succession (18 years after clear-cutting). Net primary production of the 18-year-old forest in this study was 5.2 tC ha(-1 )year(-1), including below-ground coarse roots; this was partitioned into 2.5 tC ha(-1 )year(-1) biomass increment, 1.6 tC ha(-1 )year(-1) foliage litter, and 1.0 tC ha(-1 )year(-1) other woody detritus. The total amount of annual soil surface CO(2) efflux was 6.8 tC ha(-1 )year(-1), which included root respiration (1.9 tC ha(-1 )year(-1)) and heterotrophic respiration (RH) from soils (4.9 tC ha(-1 )year(-1)). The 18-year forest at this study site exhibited a great increase in biomass pool as a result of considerable total tree growth and low mortality of tree stems. In contrast, the soil organic matter (SOM) pool decreased markedly (-1.6 tC ha(-1 )year(-1)), although further study of below-ground detritus production and RH of SOM decomposition is needed. This young 18-year forest was a weak carbon sink (0.9 tC ha(-1 )year(-1)) at this stage of secondary succession. The NEP of this 18-year forest is likely to increase gradually because biomass increases with tree growth and with the improvement of the SOM pool through increasing litter and dead wood production with stand development.

  10. Modelling carbon cycle of agro-forest ecosystems in Lombardy (Italy

    Directory of Open Access Journals (Sweden)

    Colombo R

    2009-09-01

    Full Text Available In this paper we present a methodology for the estimation of Gross Primary Production (GPP, Net Primary Production (NPP and Net Ecosystem Production (NEP for the main agricultural and forest ecosystems of the Lombardia Region (Italy. The MOD17 model was parameterized according to the different agro-forestry ecosystems and applied at regional scale by using satellite data with a spatial resolution of 250m. The high spatial resolution along with fine classification agro-forestry ecosystems has allowed to accurately analyze the carbon budget of an extremely fragmented and complex environment such as the Lombardia Region. Modeling results showed the role of the forests in the carbon budget at regional scale and represent important information layer for the spatial analysis and for inferring the inter-annual variability of carbon sequestration due to impacts of extreme events and recent climate change (e.g., drought, heat wave, flooding, fires.

  11. Projected Effects of CO2 Enrichment on Community Dynamics and Carbon Cycling in an Early-successional Forest

    Science.gov (United States)

    Miller, A. D.; Dietze, M.; DeLucia, E. H.; Anderson-Teixeira, K. J.

    2013-12-01

    Early-successional forests are strong carbon (C) sinks that play an important role in the global C cycle. Elevated CO2 may alter C cycling in regenerating forests both directly through ecophysiological mechanisms and indirectly through altered community dynamics, which may be particularly important in early successional forests with high community turnover. Thus, to discriminate impacts of CO2 enrichment on C cycles in regenerating forests it is necessary to characterize how the physiological and successional mechanisms that regulate the C cycle are altered by climate change. Because species are known to display differential growth stimulus under CO2 enrichment, and these species-specific effects are grouped by classic plant functional type, we hypothesize that successional trajectories will be altered in high CO2 forests, compared to forests regenerating under historic climatic conditions. To test this hypothesis, we use the Ecosystem Demography model (ED2), a height- and successional-structured terrestrial biosphere model to predict possible effects of elevated CO2 on forest succession. Using data from the Duke Free Air CO2 Enrichment (FACE) experiment and a nearby chronosequence of pine forests to parameterize and evaluate the model, we use ED2 to project how plant demography and competition will react to elevated CO2 over a 50-100 year time frame. We evaluate the sensitivity of model results to a variety of model configurations, and demonstrate that the outcomes are largely robust to structural uncertainty regarding assumptions about nitrogen limitation and water availability. The model predicts that elevated CO2 will alter C cycling directly through ecophysiological effect and indirectly through altered community dynamics, which in turn affect C cycling. For instance, late-successional hardwood species will receive more benefit on average from elevated CO2, than early-successional hardwoods. After 50 years of 550 ppm CO2, late-successional hardwoods experience

  12. Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon

    Science.gov (United States)

    Berner, L. T.; Law, B. E.

    2015-11-01

    Severe droughts occurred in the western United States during recent decades, and continued human greenhouse gas emissions are expected to exacerbate warming and drying in this region. We investigated the role of water availability in shaping forest carbon cycling and morphological traits in the eastern Cascade Mountains, Oregon, focusing on the transition from low-elevation, dry western juniper (Juniperus occidentalis) woodlands to higher-elevation, wetter ponderosa pine (Pinus ponderosa) and grand fir (Abies grandis) forests. We examined 12 sites in mature forests that spanned a 1300 mm yr-1 gradient in mean growing-year climate moisture index (CMIgy ), computed annually (1964 to 2013) as monthly precipitation minus reference evapotranspiration and summed October to September. Maximum leaf area, annual aboveground productivity, and aboveground live tree biomass increased with CMIgy (r2 = 0.67-0.88, P gy (r2 = 0.53, P gy and extensive insect outbreak. Traits of stress-tolerant juniper included short stature, high wood density for cavitation resistance, and high investment in water transport relative to leaf area. Species occupying wetter areas invested more resources in height growth in response to competition for light relative to investment in hydraulic architecture. Consequently, maximum tree height, leaf area : sapwood area ratio, and stem wood density were all correlated with CMIgy . The tight coupling of forest carbon cycling and species traits with water availability suggests that warmer and drier conditions projected for the 21st century could have significant biogeochemical, ecological, and social consequences in the Pacific Northwest.

  13. Tree species diversity mitigates disturbance impacts on the forest carbon cycle.

    Science.gov (United States)

    Pedro, Mariana Silva; Rammer, Werner; Seidl, Rupert

    2015-03-01

    Biodiversity fosters the functioning and stability of forest ecosystems and, consequently, the provision of crucial ecosystem services that support human well-being and quality of life. In particular, it has been suggested that tree species diversity buffers ecosystems against the impacts of disturbances, a relationship known as the "insurance hypothesis". Natural disturbances have increased across Europe in recent decades and climate change is expected to amplify the frequency and severity of disturbance events. In this context, mitigating disturbance impacts and increasing the resilience of forest ecosystems is of growing importance. We have tested how tree species diversity modulates the impact of disturbance on net primary production and the total carbon stored in living biomass for a temperate forest landscape in Central Europe. Using the simulation model iLand to study the effect of different disturbance regimes on landscapes with varying levels of tree species richness, we found that increasing diversity generally reduces the disturbance impact on carbon storage and uptake, but that this effect weakens or even reverses with successional development. Our simulations indicate a clear positive relationship between diversity and resilience, with more diverse systems experiencing lower disturbance-induced variability in their trajectories of ecosystem functioning. We found that positive effects of tree species diversity are mainly driven by an increase in functional diversity and a modulation of traits related to recolonization and resource usage. The results of our study suggest that increasing tree species diversity could mitigate the effects of intensifying disturbance regimes on ecosystem functioning and improve the robustness of forest carbon storage and the role of forests in climate change mitigation.

  14. Modeling the impact of disturbances on the carbon cycle of a mixed-deciduous forest in the upper Midwest

    Science.gov (United States)

    Frasson, R.; Bohrer, G.; Medvigy, D.; Ivanov, V. Y.; Vogel, C.; Curtis, P.

    2013-12-01

    Disturbances, either natural or anthropogenic, impact the carbon and water cycles. Therefore, understanding their immediate effect, as well as how fluxes evolve while forests recover from disturbances is essential to carbon and water cycle modeling. Our study area is located in northern Michigan and encompasses the mixed-deciduous forest surrounding the University of Michigan Biological Station (UMBS). The two AmeriFlux affiliated towers operated by the UMBS, one with an undisturbed footprint and a second overlooking the Forest Accelerated Succession ExperimenT (FASET) site, a 39 ha area where all aspen (Populus spp.) and birch (Betula papyrifera) trees were girdled, provides the supporting data for our study. We used the Ecosystem Demography model version 2 (ED2) to run three scenarios: a control (undisturbed) case, a homogeneous disturbance (dist-1) where 30% of the leaf area was removed regardless of functional type, and a FASET like disturbance (dist-2) where all early successional trees, which occupy 30% of leaf area, were removed. We parameterized ED2 using observations of monthly and yearly net ecosystem exchange (NEE), latent, and sensible heat fluxes from the undisturbed site (UMBS-AmeriFlux) from pre-disturbance years. We force the model using meteorological data recorded by the flux towers and evaluate the output of the three cases against NEE, latent, and sensible heat fluxes measured at the UMBS-AmeriFlux site (undisturbed case) and against the FASET tower (cases dist-1 and dist-2) after the disturbance occurred. Our results indicate that in such a case of an intermediate disturbance the results of the disturbance are defendant on the functional type that was affected. As a result of this study, we expect to improve the understanding of the role disturbances and the subsequent recovery on carbon and water fluxes of broadleaved deciduous forests.

  15. Iron: A Biogeochemical Engine That Drives Carbon, Nitrogen, and Phosphorus Cycling in Humid Tropical Forest Soils

    Science.gov (United States)

    Silver, W. L.; Hall, S. J.; Thompson, A.; Yang, W. H.

    2014-12-01

    rapidly immobilized into biological pools (Liptzin and Silver 2009). Data suggest that Fe-redox cycling may decrease P limitation to NPP, and help maintain forest nutrient stocks. In summary, our results highlight the biogeochemical significance of Fe cycling in upland soils environments and its important role in the dynamics of humid tropical forests.

  16. Different types of nitrogen deposition show variable effects on the soil carbon cycle process of temperate forests.

    Science.gov (United States)

    Du, Yuhan; Guo, Peng; Liu, Jianqiu; Wang, Chunyu; Yang, Ning; Jiao, Zhenxia

    2014-10-01

    Nitrogen (N) deposition significantly affects the soil carbon (C) cycle process of forests. However, the influence of different types of N on it still remained unclear. In this work, ammonium nitrate was selected as an inorganic N (IN) source, while urea and glycine were chosen as organic N (ON) sources. Different ratios of IN to ON (1 : 4, 2 : 3, 3 : 2, 4 : 1, and 5 : 0) were mixed with equal total amounts and then used to fertilize temperate forest soils for 2 years. Results showed that IN deposition inhibited soil C cycle processes, such as soil respiration, soil organic C decomposition, and enzymatic activities, and induced the accumulation of recalcitrant organic C. By contrast, ON deposition promoted these processes. Addition of ON also resulted in accelerated transformation of recalcitrant compounds into labile compounds and increased CO2 efflux. Meanwhile, greater ON deposition may convert C sequestration in forest soils into C source. These results indicated the importance of the IN to ON ratio in controlling the soil C cycle, which can consequently change the ecological effect of N deposition.

  17. Tree-fall gaps and carbon cycling in the Brazilian Amazon: results from two large forest plots

    Science.gov (United States)

    Espirito-Santo, F.; Keller, M.; Linder, E.; De Oliveira, R., Jr.; Pereira, C.; Oliveira, C. G.

    2013-12-01

    The dynamics of gaps play a role in the regimes of tree mortality and production of coarse woody debris (CWD) in forests. Few studies have attempted to map the distribution of gaps in tropical forest and the production of CWD, a large pool of ecosystem carbon. Here we linked gap formation with carbon cycling through analysis of the CWD inside of gaps. We surveyed two large forest inventory plots of 114 and 53 ha of the Tapajós National Forest (TNF) in the Brazilian Amazon during 2008 and 2009, respectively. We mapped all gaps and collected data on light availability, CWD stocks and tree mortality in the field. Gap location, canopy opening (CO) and leaf area index (LAI) estimated in the field were compared with two IKONOS-2 high-resolution satellite images acquired approximately at the time of the field measurements. We provide the first statistics of CWD production based on gap size in the tropical forest literature. In the two large plots (167 ha total area) we found 96 gaps. The gaps represented 1.42% of the total area and gaps TNF, the production of CWD in recent gaps was 0.76 Mg C ha-1 year-1 and the mean tree mortality was 2.38 stems ha-1 year 1. The area of gaps estimated by using thresholds of light intensity measured by remote sensing optical instruments was twice as large as the gap areas measured on the ground. We found no significant correlation between spectral remote sensing images and CO and LAI, likely because the high faction of shadow in high-resolution satellite images. We conclude that less than 30% of the annual tree mortality and CWD flux was associated with gaps and the detection of gaps with high resolution optical remote sensing remains a challenge because of the high proportion of shadow in the those images. These results highlight the need for permanent plots for long-term carbon studies.

  18. Trading forest carbon

    Science.gov (United States)

    The nature of carbon in forests is discussed from the perspective of carbon trading. Carbon inventories, specifically in the area of land use and forestry are reviewed for the Pacific Northwest. Carbon turnover in forests is discussed as it relates to carbon sequestration. Scient...

  19. Water limitations on forest carbon cycling and conifer traits along a steep climatic gradient in the Cascade Mountains, Oregon

    Directory of Open Access Journals (Sweden)

    L. T. Berner

    2015-09-01

    Full Text Available Severe droughts occurred in the western United States during recent decades and continued human greenhouse gas emissions are expected to exacerbate warming and drying in this region. We investigated the role of water availability in shaping forest carbon cycling and morphological traits in the eastern Cascade Mountains, Oregon, focusing on the transition from low-elevation, dry western juniper (Juniperus occidentalis woodlands to higher-elevation, wetter ponderosa pine (Pinus ponderosa and grand fir (Abies grandis forests. We examined 12 sites in mature forests that spanned a 1300 mm yr−1 gradient in mean growing-year climate moisture index (CMIgy , computed annually (1964 to 2013 as monthly precipitation minus reference evapotranspiration and summed October to September. Maximum leaf area, annual aboveground productivity, and aboveground live tree biomass increased with CMIgy (r2 = 0.58–0.85, P gy (r2 = 0.65, P gy and extensive insect outbreak. Traits of stress-tolerant juniper included short stature, high wood density for cavitation resistance, and high investment in water transport relative to leaf area. Species occupying wetter areas invested more resources in height growth in response to competition for light relative to investment in hydraulic architecture. Correspondingly, maximum tree height, leaf area:sapwood area ratio, and stem wood density were all correlated with CMIgy . The tight coupling of forest carbon cycling and species traits with water availability suggests that warmer and drier conditions projected for the 21st century could have significant biogeochemical, ecological, and social consequences in the Pacific Northwest.

  20. Modeling forest carbon and nitrogen cycles based on long term carbon stock field measurement in the Delaware River Basin

    Science.gov (United States)

    Xu, B.; Pan, Y.; McCullough, K.; Plante, A. F.; Birdsey, R.

    2015-12-01

    Process-based models are a powerful approach to test our understanding of biogeochemical processes, to extrapolate ground survey data from limited plots to the landscape scale and to simulate the effects of climate change, nitrogen deposition, elevated atmospheric CO2, increasing natural disturbances and land use change on ecological processes. However, in most studies, the models are calibrated using ground measurements from only a few sites, though they may be extrapolated to much larger areas. Estimation accuracy can be improved if the models are parameterized using long-term carbon stock data from multiple sites representative of the simulated region. In this study, vegetation biomass and soil carbon stocks, and changes in these stocks over a recent decade, were measured in 61 forested plots located in three small watersheds in the Delaware River Basin (DRB). On average, total vegetation biomass was 160.2 Mg C ha-1 and the soil carbon stock was 76.6 Mg C ha-1, measured during 2012-2014. The biomass carbon stock increased by 2.45 Mg C ha-1 yr-1 from 2001-2003 to 2012-2014. This dataset was subsequently used to parameterize the PnET-CN model at the individual plot basis, and averaged parameters among plots were then applied to generate new watershed-scale model parameters for each of the three watersheds. The parameterized model was further validated by the field measurements in each of the major forest types. The spatial distribution of forest carbon pools and fluxes in three watersheds were mapped based on the simulation results from the newly parameterized PnET-CN model. The model will also be run under different scenarios to test the effects of climate change, altered atmospheric composition, land use change, and their interactions within the three watersheds and across the whole DRB.

  1. Water cycle investigations in Hungarian forest ecosystems

    Institute of Scientific and Technical Information of China (English)

    Judit Sitkey

    2006-01-01

    From the biological point of view the value of autotrophy plant association is determined by the carbon fixation and the carbon cycle. Among the plant associations of Hungary, forest has the largest biological carbon fixation and carbon cycle. In general,the annual water cycle is the key factor in the organic material production of the Hungarian forests. The most intensive water consumption and organic material production take place from May till July, which period is named main water consumption and respectively main growing period. In Hungary the categories of the forest climate are characterized by main tree species and based on the forest climate covers 8% of the forest area, hornbeam-oak forest climate covers 22%, sessile oak-Turkey oak forest climate covers48% and forest steppe climate covers 22%. Partly in the frame of ICP-Forests, the Department of Ecology in the Forest Research Institute carries out long term, complex ecophysiological investigations on several sample plots (so-called basic plots) throughout the whole country. The organic material production (growth), the nutrient and water cycle, the measurements of air pollutants and meteorological parameters, as well as chemical analyses are all part of the investigations. As a comparison the figure of two basic plotsforest steppe climate in the hydrological year of 2001-2002. In the Hungarian forest 60%-70% of the precipitation is used for interception, evaporation, and in the vegetation season, for the transpiration both in beech and forest steppe climate. From other point of view, only 30%-40% of the open air precipitation infiltrates into the soil and can be utilized by the forest.

  2. Impacts of Thermokarst Formation and Wildfire on Boreal Forest Carbon Cycling

    Science.gov (United States)

    Fisher, J. P.; Estop-Aragones, C.; Thierry, A.; Hartley, I. P.; Murton, J.; Charman, D.; Williams, M.; Phoenix, G. K.

    2014-12-01

    At the global scale permafrost temperatures are increasing, leading to a thickening of the active layer and an increase in the amount of previously immobilised C exposed to microbial decay and subsequent release to the atmosphere. Against the backdrop of this overall trend, perturbations to permafrost systems caused by wildfires or thermokarst driven wetland formation can cause dramatic shifts in the C exchange of these ecosystems as a result of the changes in plant communities and soil thermal regimes they cause. These dynamic components of permafrost landscapes are often neglected in coupled climate-C models. However, a clear understanding of the impact of these perturbations on C cycling is crucial if we are to accurately predict future permafrost feedbacks to climate change. This is particularly pertinent given that the frequency of both forest fires and thermokarst formation is likely to increase with future climate warming. In order to assess the impact of these perturbations on C cycling we established paired burned and unburned spruce forest and paired peat plateau and thaw feature field sites near Whitehorse, YT and Yellowknife, NT within the boreal region of Canada. At each site tree photosynthetic biomass was quantified using DBH based allometric scaling equations. A combination of percentage cover surveys, biomass harvests, and leaf area determination were used to calculate understory and wetland photosynthetic biomass. Measurements of spruce and understory photosynthesis and plant and soil respiration were made using specialised acrylic chambers and an IRGA. Combining these data has allowed us to determine the impact of thermokarst formation and wildfire on C exchange with the atmosphere. This has allowed us to assess whether the dramatic increase in plant productivity between peat plateau and wetland habitats has the potential to offset thermokarst associated C losses. We have also gained an understanding of whether increases in light availability for

  3. Climate extremes and the carbon cycle - a review using an integrated approach with regional examples for forests & native ecosystems -

    Science.gov (United States)

    Frank, D.; Reichstein, M.; Bahn, M.; Beer, C.; Ciais, P.; Mahecha, M.; Seneviratne, S. I.; Smith, P.; van Oijen, M.; Walz, A.

    2012-04-01

    The terrestrial carbon cycle provides an important biogeochemical feedback to climate and is itself particularly susceptible to extreme climate events. Climate extremes can override any (positive) effects of mean climate change as shown in European and recent US-American heat waves and dry spells. They can impact the structure, composition, and functioning of terrestrial ecosystems and have the potential to cause rapid carbon losses from accumulated stocks. We review how climate extremes like severe droughts, heat waves, extreme precipitation or storms can cause direct impacts on the CO2 fluxes [e.g. due to extreme temperature and/ or drought events] as well as lagged impacts on the carbon cycle [e.g. via an increased fire risk, or disease outbreaks and pest invasions]. The relative impact of the different climate extremes varies according to climate region and vegetation type. We present lagged effects on plant growth (and mortality) in the year(s) following an extreme event and their impacts on the carbon sequestration of forests and natural ecosystems. Comprehensive regional or even continental quantification with regard to extreme events is missing, and especially compound extreme events, the role of lagged effects and aspects of the return frequency are not studied enough. In a case study of a Mediterranean ecosystem we illustrate that the response of the net carbon balance at ecosystem level to regional climate change is hard to predict as interacting and partly compensating processes are affected and several processes which have the ability to substantially alter the carbon balance are not or not sufficiently represented in state-of-the-art biogeochemical models.

  4. The influence of climate changes on carbon cycle in the russian forests. Data inventory and long-scale model prognoses

    Energy Technology Data Exchange (ETDEWEB)

    Kokorin, A.O.; Nazarov, I.M.; Lelakin, A.L. [Inst. Global Climate and Ecology, Moscow (Russian Federation)

    1995-12-31

    The growing up climate changes arise the question about reaction of forests. Forests cover 770 Mha in Russia and are giant carbon reservoir. Climate changes cause disbalance in carbon budget that give additional CO{sub 2} exchange between forests and the atmosphere. The aim of the work is estimation of these fluxes. This problem is directly connected with an GHG inventory, vulnerability and mitigation assessment, which are necessary for future Russian Reports to UN FCCC. The work includes the following steps: (1) Collection of literature data as well as processing of the experimental data on influence of climate changes on forests, (2) Calculation of carbon budget as base for calculations of CO{sub 2} fluxes, (3) Developing of new version of CCBF (Carbon and Climate in Boreal Forests) model, (4) Model estimations of current and future CO{sub 2} fluxes caused by climate changes, forest cuttings, fires and reforestation

  5. Anthropogenic nitrogen deposition in boreal forests has a minor impact on the global carbon cycle.

    Science.gov (United States)

    Gundale, Michael J; From, Fredrik; Bach, Lisbet H; Nordin, Annika

    2014-01-01

    It is proposed that increases in anthropogenic reactive nitrogen (Nr ) deposition may cause temperate and boreal forests to sequester a globally significant quantity of carbon (C); however, long-term data from boreal forests describing how C sequestration responds to realistic levels of chronic Nr deposition are scarce. Using a long-term (14-year) stand-scale (0.1 ha) N addition experiment (three levels: 0, 12.5, and 50 kg N ha(-1)  yr(-1) ) in the boreal zone of northern Sweden, we evaluated how chronic N additions altered N uptake and biomass of understory communities, and whether changes in understory communities explained N uptake and C sequestration by trees. We hypothesized that understory communities (i.e. mosses and shrubs) serve as important sinks for low-level N additions, with the strength of these sinks weakening as chronic N addition rates increase, due to shifts in species composition. We further hypothesized that trees would exhibit nonlinear increases in N acquisition, and subsequent C sequestration as N addition rates increased, due to a weakening understory N sink. Our data showed that understory biomass was reduced by 50% in response to the high N addition treatment, mainly due to reduced moss biomass. A (15) N labeling experiment showed that feather mosses acquired the largest fraction of applied label, with this fraction decreasing as the chronic N addition level increased. Contrary to our hypothesis, the proportion of label taken up by trees was equal (ca. 8%) across all three N addition treatments. The relationship between N addition and C sequestration in all vegetation pools combined was linear, and had a slope of 16 kg C kg(-1)  N. While canopy retention of Nr deposition may cause C sequestration rates to be slightly different than this estimate, our data suggest that a minor quantity of annual anthropogenic CO2 emissions are sequestered into boreal forests as a result of Nr deposition. © 2013 John Wiley & Sons Ltd.

  6. The role of forest trees and their mycorrhizal fungi in carbonate rock weathering and its significance for global carbon cycling.

    Science.gov (United States)

    Thorley, Rachel M S; Taylor, Lyla L; Banwart, Steve A; Leake, Jonathan R; Beerling, David J

    2015-09-01

    On million-year timescales, carbonate rock weathering exerts no net effect on atmospheric CO2 concentration. However, on timescales of decades-to-centuries, it can contribute to sequestration of anthropogenic CO2 and increase land-ocean alkalinity flux, counteracting ocean acidification. Historical evidence indicates this flux is sensitive to land use change, and recent experimental evidence suggests that trees and their associated soil microbial communities are major drivers of continental mineral weathering. Here, we review key physical and chemical mechanisms by which the symbiotic mycorrhizal fungi of forest tree roots potentially enhance carbonate rock weathering. Evidence from our ongoing field study at the UK's national pinetum confirms increased weathering of carbonate rocks by a wide range of gymnosperm and angiosperm tree species that form arbuscular (AM) or ectomycorrhizal (EM) fungal partnerships. We demonstrate that calcite-containing rock grains under EM tree species weather significantly faster than those under AM trees, an effect linked to greater soil acidification by EM trees. Weathering and corresponding alkalinity export are likely to increase with rising atmospheric CO2 and associated climate change. Our analyses suggest that strategic planting of fast-growing EM angiosperm taxa on calcite- and dolomite-rich terrain might accelerate the transient sink for atmospheric CO2 and slow rates of ocean acidification.

  7. Trading forest carbon - OSU

    Science.gov (United States)

    Issues associate with trading carbon sequestered in forests are discussed. Scientific uncertainties associated with carbon measurement are discussed with respect to proposed accounting procedures. Major issues include: (1) Establishing baselines. (2) Determining additivity from f...

  8. Trading forest carbon - OSU

    Science.gov (United States)

    Issues associate with trading carbon sequestered in forests are discussed. Scientific uncertainties associated with carbon measurement are discussed with respect to proposed accounting procedures. Major issues include: (1) Establishing baselines. (2) Determining additivity from f...

  9. Evaluating a Coupled Carbon and Nitrogen Cycle Model at a Pacific Northwest Douglas-fir Forest in Canada

    Science.gov (United States)

    Arain, M.; Yuan, F.; Shaikh, M.; Black, T.

    2004-05-01

    Nitrogen availability could be a key factor to enhance or limit plant photosynthesis under global climate change. This study presents a coupled nitrogen and carbon cycle model incorporated in the Canadian Land Surface Scheme (CLASS) which is used in the Canadian General Circulation Model. The nitrogen cycle model, which follows Dickinson et al., 2002 is coupled to a previously derived carbon model in CLASS. Nitrogen cycling processes taken into account include biological fixation, soil mineralization, immobilization, nitrification, denitrification, volatilization, leaching, root uptake and allocation to various plant components. Root nitrogen uptake depends on soil mineral nitrogen content, ion physical transport, root interface, and also on plant-growth demand for this nutrient. Leaf Rubisco-nitrogen concentration was modeled to determine variations in maximum rate of Rubisco activity,Vcmax. The coupled carbon and nitrogen model was tested at a Douglas-fir forest, growing on Vancouver Island, British Columbia, Canada, using observed eddy covariance flux data from 1998 to 2000. Simulated carbon and nitrogen uptake/loss rates were in broad agreement with observation. The simulated annual soil mineralized nitrogen was 6.3, 5.3, and 6.0 g m-2 in 1998, 1999 and 2000, respectively. The annual nitrogen uptake was 1.78, 1.65, and 1.76 g m-2, respectively. The simulated leaf nitrogen ranged from 1.81 to 1.87 g m-2 leaf area in the growing season, while observed leaf nitrogen values were 1.7 g m-2 in the lower canopy, and 2.56 g m-2 in the upper canopy. Observed Rubisco nitrogen was about 17% of total leaf nitrogen as compared to 16% simulated value. The modeled Vcmax in top leaves (Vcmax0) was as low as 15 imol C m-2 s-1 during the non-growing season, and as high as 80 imol C m-2 s-1 during the full growing season. Comparison of half-hourly observed and simulated gross ecosystem productivity (GEP), ecosystem respiration (R) and net ecosystem productivity (NEP) from 1998

  10. Impact of the Mountain Pine Beetle on the Forest Carbon Cycle in British Columbia from 1999 TO 2008 (Invited)

    Science.gov (United States)

    Chen, J. M.; Czurylowicz, P.; Mo, G.; Black, T. A.

    2013-12-01

    The unprecedented mountain pine beetle (Dendroctonus ponderosae) (MPB) outbreak in British Columbia starting in 1998 affected about 50% of the lodgepole pine (Pinus contorta var. latifolia) forests occupying about 50% of the land area of the province. The impact of this outbreak on the C cycle is assessed in this study. Annual leaf area index (LAI) maps of the affected area from 1999 to 2008 were produced using SPOT VEGETATION data, and net ecosystem production (NEP) was modeled using inputs of LAI, land cover, soil texture and daily meteorological data with the Boreal Ecosystem Productivity Simulator (BEPS). Both LAI and NEP were validated using field measurements. LAI was found to decrease on average by 20% compared to pre-outbreak conditions, while NEP decreased on average by 90%. Annual NEP values ranged from 2.4 to -8.0 Tg C between 1999 and 2008, with the ecosystem changing from a carbon sink to a carbon source in 2000. The annual average NEP was -2.9 Tg C over the 10 years, resulting in a total loss of carbon of 29 Tg C to the atmosphere. The inter-annual variability of both LAI and NEP was characterized by substantial initial decreases followed by steady increases from 2006 to 2008 with NEP returning to near carbon neutrality in 2008 (-1.8 Pg C/y). The impact of this MPB outbreak appears to be less dramatic than previously anticipated. The apparent fast recovery of LAI and NEP after MPB attacks is examined under the framework of ecosystem resilience which was manifested in the form of secondary overstory and understory growth and increased production of non-attacked host trees.

  11. Variation of carbon and nitrogen cycling processes along a topographic gradient in a central Amazonian forest

    NARCIS (Netherlands)

    Luizão, R.C.C.; Luizão, F.J.; Paiva, R.Q.; Monteiro, T.F.; Sousa, L.S.; Kruijt, B.

    2004-01-01

    It is well recognized in the literature that topography can influence soil nutrient stocks and dynamics in temperate regions, but for tropical forests, this source of variation has sometimes been ignored. The nature of such variations may depend upon the soil type, which in turn, is closely linked t

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    , tree growth, litter production and leaching of dissolved inorganic and organic carbon were independently estimated and used to calculate other unmeasured ecosystem carbon budget (ECB) components, based on mass balance equations. This provided a complete assessment of the carbon storage and allocation...... was considered unchanged over the period of observation, given the high degree of uncertainty associated with the small loss detected (33±85gCm−2 yr−1). The ECB component data were generally consistent, except for one of the derived fluxes, the aboveground autotrophic respiration, which appeared to be higher...... than expected. The potential causes for this, i.e. underestimation of soil respiration and/or overestimation of Re are discussed. The plausibility analyses reported here, using multiple ECB data sets together with simple mass conservation equations and the evaluation of data consistency on the basis...

  13. Carbon-nitrogen interactions in forest ecosystems

    DEFF Research Database (Denmark)

    Gundersen, Per; Berg, Bjørn; Currie, W.S.;

    This report is a summary of the main results from the EU project “Carbon – Nitrogen Interactions in Forest Ecosystems” (CNTER). Since carbon (C) and nitrogen (N) are bound together in organic matter we studied both the effect of N deposition on C cycling in forest ecosystems, and the effect of C...... accumulation on N storage and release. Based on compiled databases on element pools and fluxes from several hundred forest sites, process studies in long-term nitrogen manipulation experiments and modelling efforts we estimated C sequestration and N retention in European forest soils. Further, we studied...... the impact of forest management on C sequestration, N retention and N leaching....

  14. Securing tropical forest carbon

    DEFF Research Database (Denmark)

    Scharlemann, Jörn P. W.; Kapos, Valerie; Campbell, Alison;

    2010-01-01

    Forest loss and degradation in the tropics contribute 6-17% of all greenhouse gas emissions. Protected areas cover 217.2 million ha (19.6%) of the world's humid tropical forests and contain c. 70.3 petagrams of carbon (Pg C) in biomass and soil to 1 m depth. Between 2000 and 2005, we estimate...... that 1.75 million ha of forest were lost from protected areas in humid tropical forests, causing the emission of 0.25-0.33 Pg C. Protected areas lost about half as much carbon as the same area of unprotected forest. We estimate that the reduction of these carbon emissions from ongoing deforestation...... in protected sites in humid tropical forests could be valued at USD 6,200-7,400 million depending on the land use after clearance. This is >1.5 times the estimated spending on protected area management in these regions. Improving management of protected areas to retain forest cover better may be an important...

  15. Animating the Carbon Cycle

    OpenAIRE

    2014-01-01

    Understanding the biogeochemical processes reg- ulating carbon cycling is central to mitigating atmospheric CO2 emissions. The role of living organisms has been accounted for, but the focus has traditionally been on contributions of plants and microbes. We develop the case that fully ‘‘animating’’ the carbon cycle requires broader consideration of the functional role of animals in mediating biogeochemical processes and quanti- fication of their effects on carbon storage and exchange among ter...

  16. Exotic grasses and nitrate enrichment alter soil carbon cycling along an urban-rural tropical forest gradient.

    Science.gov (United States)

    Cusack, Daniela F; Lee, Joseph K; McCleery, Taylor L; LeCroy, Chase S

    2015-12-01

    Urban areas are expanding rapidly in tropical regions, with potential to alter ecosystem dynamics. In particular, exotic grasses and atmospheric nitrogen (N) deposition simultaneously affect tropical urbanized landscapes, with unknown effects on properties like soil carbon (C) storage. We hypothesized that (H1) soil nitrate (NO3 (-) ) is elevated nearer to the urban core, reflecting N deposition gradients. (H2) Exotic grasslands have elevated soil NO3 (-) and decreased soil C relative to secondary forests, with higher N promoting decomposer activity. (H3) Exotic grasslands have greater seasonality in soil NO3 (-) vs. secondary forests, due to higher sensitivity of grassland soil moisture to rainfall. We predicted that NO3 (-) would be positively related to dissolved organic C (DOC) production via changes in decomposer activity. We measured six paired grassland/secondary forest sites along a tropical urban-to-rural gradient during the three dominant seasons (hurricane, dry, and early wet). We found that (1) soil NO3 (-) was generally elevated nearer to the urban core, with particularly clear spatial trends for grasslands. (2) Exotic grasslands had lower soil C than secondary forests, which was related to elevated decomposer enzyme activities and soil respiration. Unexpectedly, soil NO3 (-) was negatively related to enzyme activities, and was lower in grasslands than forests. (3) Grasslands had greater soil NO3 (-) seasonality vs. forests, but this was not strongly linked to shifts in soil moisture or DOC. Our results suggest that exotic grasses in tropical regions are likely to drastically reduce soil C storage, but that N deposition may have an opposite effect via suppression of enzyme activities. However, soil NO3 (-) accumulation here was higher in urban forests than grasslands, potentially related to of aboveground N interception. Net urban effects on C storage across tropical landscapes will likely vary depending on the mosaic of grass cover, rates of N

  17. Drought effects on litterfall, wood production and belowground carbon cycling in an Amazon forest: results of a throughfall reduction experiment.

    Science.gov (United States)

    Brando, Paulo M; Nepstad, Daniel C; Davidson, Eric A; Trumbore, Susan E; Ray, David; Camargo, Plínio

    2008-05-27

    The Amazon Basin experiences severe droughts that may become more common in the future. Little is known of the effects of such droughts on Amazon forest productivity and carbon allocation. We tested the prediction that severe drought decreases litterfall and wood production but potentially has multiple cancelling effects on belowground production within a 7-year partial throughfall exclusion experiment. We simulated an approximately 35-41% reduction in effective rainfall from 2000 through 2004 in a 1ha plot and compared forest response with a similar control plot. Wood production was the most sensitive component of above-ground net primary productivity (ANPP) to drought, declining by 13% the first year and up to 62% thereafter. Litterfall declined only in the third year of drought, with a maximum difference of 23% below the control plot. Soil CO2 efflux and its 14C signature showed no significant treatment response, suggesting similar amounts and sources of belowground production. ANPP was similar between plots in 2000 and declined to a low of 41% below the control plot during the subsequent treatment years, rebounding to only a 10% difference during the first post-treatment year. Live aboveground carbon declined by 32.5Mgha-1 through the effects of drought on ANPP and tree mortality. Results of this unreplicated, long-term, large-scale ecosystem manipulation experiment demonstrate that multi-year severe drought can substantially reduce Amazon forest carbon stocks.

  18. Carbon-nitrogen interactions in forest ecosystems

    DEFF Research Database (Denmark)

    Gundersen, Per; Berg, Bjørn; Currie, W.S.

    This report is a summary of the main results from the EU project “Carbon – Nitrogen Interactions in Forest Ecosystems” (CNTER). Since carbon (C) and nitrogen (N) are bound together in organic matter we studied both the effect of N deposition on C cycling in forest ecosystems, and the effect of C...... accumulation on N storage and release. Based on compiled databases on element pools and fluxes from several hundred forest sites, process studies in long-term nitrogen manipulation experiments and modelling efforts we estimated C sequestration and N retention in European forest soils. Further, we studied...

  19. Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

    Directory of Open Access Journals (Sweden)

    M. Ueyama

    2010-03-01

    Full Text Available Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales.

    The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE, gross primary productivity (GPP, ecosystem respiration (RE, and evapotranspiration (ET. Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, substantially improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values.

    The observed and simulated GPP and RE across the six sites were positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget was partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicated that spring warming enhanced the carbon sink, whereas summer warming decreased it across the larch forests. The summer radiation was the most important factor that controlled the carbon fluxes in the temperate site, but the VPD and water conditions were the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between belowground and aboveground, was site-specific, and it was negatively correlated with the annual climate of annual mean air temperature and total precipitation

  20. Simulating carbon and water cycles of larch forests in East Asia by the BIOME-BGC model with AsiaFlux data

    Directory of Open Access Journals (Sweden)

    M. Ueyama

    2009-08-01

    Full Text Available Larch forests are widely distributed across many cool-temperate and boreal regions, and they are expected to play an important role in global carbon and water cycles. Model parameterizations for larch forests still contain large uncertainties owing to a lack of validation. In this study, a process-based terrestrial biosphere model, BIOME-BGC, was tested for larch forests at six AsiaFlux sites and used to identify important environmental factors that affect the carbon and water cycles at both temporal and spatial scales.

    The model simulation performed with the default deciduous conifer parameters produced results that had large differences from the observed net ecosystem exchange (NEE, gross primary productivity (GPP, ecosystem respiration (RE, and evapotranspiration (ET. Therefore, we adjusted several model parameters in order to reproduce the observed rates of carbon and water cycle processes. This model calibration, performed using the AsiaFlux data, significantly improved the model performance. The simulated annual GPP, RE, NEE, and ET from the calibrated model were highly consistent with observed values.

    The observed and simulated GPP and RE across the six sites are positively correlated with the annual mean air temperature and annual total precipitation. On the other hand, the simulated carbon budget is partly explained by the stand disturbance history in addition to the climate. The sensitivity study indicates that spring warming enhances the carbon sink, whereas summer warming decreases it across the larch forests. The summer radiation is the most important factor that controls the carbon fluxes in the temperate site, but the VPD and water conditions are the limiting factors in the boreal sites. One model parameter, the allocation ratio of carbon between aboveground and belowground, is site-specific, and it is negatively correlated with the annual climate of annual mean air temperature and total precipitation. Although

  1. The carbon dioxide cycle

    Science.gov (United States)

    James, P.B.; Hansen, G.B.; Titus, T.N.

    2005-01-01

    The seasonal CO2 cycle on Mars refers to the exchange of carbon dioxide between dry ice in the seasonal polar caps and gaseous carbon dioxide in the atmosphere. This review focuses on breakthroughs in understanding the process involving seasonal carbon dioxide phase changes that have occurred as a result of observations by Mars Global Surveyor. ?? 2004 COSPAR. Published by Elsevier Ltd. All rights reserved.

  2. Forests as carbon sinks

    Energy Technology Data Exchange (ETDEWEB)

    Houghton, R.A.; Woodwell, R.M. [Woods Hole Research Center, Woods Hole, MA (United States)

    1995-11-01

    When the nations of the world signed and later ratified the United Nations Framework Convention on Climate Change (FCCC), they accepted the difficult challenge of stabilizing the composition of the atmosphere with respect to the greenhouse gases (GHGs). Success will require a reduction in both use of fossil fuels and rates of deforestation. Forests have a large enough influence on the atmosphere that one of the options for stabilizing the concentrations of GHGs in the atmosphere includes the use of forests as a carbon sink through reforestation of large areas. We identify in this paper the potential and the limitations of such projects. We discuss the implications of four approaches in management of forests globally: (i) continued deforestation, (ii) halting deforestation, (iii) net reforestation including agroforestry, and (iv) substituting the use of wood fuels for fossil fuels.

  3. Forests as carbon sinks

    Energy Technology Data Exchange (ETDEWEB)

    Houghton, R.A.; Woodwell, R.M. [Woods Hole Research Center, Woods Hole, MA (United States)

    1995-11-01

    When the nations of the world signed and later ratified the United Nations Framework Convention on Climate Change (FCCC), they accepted the difficult challenge of stabilizing the composition of the atmosphere with respect to the greenhouse gases (GHGs). Success will require a reduction in both use of fossil fuels and rates of deforestation. Forests have a large enough influence on the atmosphere that one of the options for stabilizing the concentrations of GHGs in the atmosphere includes the use of forests as a carbon sink through reforestation of large areas. We identify in this paper the potential and the limitations of such projects. We discuss the implications of four approaches in management of forests globally: (i) continued deforestation, (ii) halting deforestation, (iii) net reforestation including agroforestry, and (iv) substituting the use of wood fuels for fossil fuels.

  4. Understanding the Effect of Land Cover Classification on Model Estimates of Regional Carbon Cycling in the Boreal Forest Biome

    Science.gov (United States)

    Kimball, John; Kang, Sinkyu

    2003-01-01

    The original objectives of this proposed 3-year project were to: 1) quantify the respective contributions of land cover and disturbance (i.e., wild fire) to uncertainty associated with regional carbon source/sink estimates produced by a variety of boreal ecosystem models; 2) identify the model processes responsible for differences in simulated carbon source/sink patterns for the boreal forest; 3) validate model outputs using tower and field- based estimates of NEP and NPP; and 4) recommend/prioritize improvements to boreal ecosystem carbon models, which will better constrain regional source/sink estimates for atmospheric C02. These original objectives were subsequently distilled to fit within the constraints of a 1 -year study. This revised study involved a regional model intercomparison over the BOREAS study region involving Biome-BGC, and TEM (A.D. McGuire, UAF) ecosystem models. The major focus of these revised activities involved quantifying the sensitivity of regional model predictions associated with land cover classification uncertainties. We also evaluated the individual and combined effects of historical fire activity, historical atmospheric CO2 concentrations, and climate change on carbon and water flux simulations within the BOREAS study region.

  5. The TERRA-PNW Dataset: A New Source for Standardized Plant Trait, Forest Carbon Cycling, and Soil Properties Measurements from the Pacific Northwest US, 2000-2014.

    Science.gov (United States)

    Berner, L. T.; Law, B. E.

    2015-12-01

    Plant traits include physiological, morphological, and biogeochemical characteristics that in combination determine a species sensitivity to environmental conditions. Standardized, co-located, and geo-referenced species- and plot-level measurements are needed to address variation in species sensitivity to climate change impacts and for ecosystem process model development, parameterization and testing. We present a new database of plant trait, forest carbon cycling, and soil property measurements derived from multiple TERRA-PNW projects in the Pacific Northwest US, spanning 2000-2014. The database includes measurements from over 200 forest plots across Oregon and northern California, where the data were explicitly collected for scaling and modeling regional terrestrial carbon processes with models such as Biome-BGC and the Community Land Model. Some of the data are co-located at AmeriFlux sites in the region. The database currently contains leaf trait measurements (specific leaf area, leaf longevity, leaf carbon and nitrogen) from over 1,200 branch samples and 30 species, as well as plot-level biomass and productivity components, and soil carbon and nitrogen. Standardized protocols were used across projects, as summarized in an FAO protocols document. The database continues to expand and will include agricultural crops. The database will be hosted by the Oak Ridge National Laboratory (ORLN) Distributed Active Archive Center (DAAC). We hope that other regional databases will become publicly available to help enable Earth System Modeling to simulate species-level sensitivity to climate at regional to global scales.

  6. Terrestrial Carbon Cycle Variability

    Science.gov (United States)

    Baldocchi, Dennis; Ryu, Youngryel; Keenan, Trevor

    2016-01-01

    A growing literature is reporting on how the terrestrial carbon cycle is experiencing year-to-year variability because of climate anomalies and trends caused by global change. As CO 2 concentration records in the atmosphere exceed 50 years and as satellite records reach over 30 years in length, we are becoming better able to address carbon cycle variability and trends. Here we review how variable the carbon cycle is, how large the trends in its gross and net fluxes are, and how well the signal can be separated from noise. We explore mechanisms that explain year-to-year variability and trends by deconstructing the global carbon budget. The CO 2 concentration record is detecting a significant increase in the seasonal amplitude between 1958 and now. Inferential methods provide a variety of explanations for this result, but a conclusive attribution remains elusive. Scientists have reported that this trend is a consequence of the greening of the biosphere, stronger northern latitude photosynthesis, more photosynthesis by semi-arid ecosystems, agriculture and the green revolution, tropical temperature anomalies, or increased winter respiration. At the global scale, variability in the terrestrial carbon cycle can be due to changes in constituent fluxes, gross primary productivity, plant respiration and heterotrophic (microbial) respiration, and losses due to fire, land use change, soil erosion, or harvesting. It remains controversial whether or not there is a significant trend in global primary productivity (due to rising CO 2, temperature, nitrogen deposition, changing land use, and preponderance of wet and dry regions). The degree to which year-to-year variability in temperature and precipitation anomalies affect global primary productivity also remains uncertain. For perspective, interannual variability in global gross primary productivity is relatively small (on the order of 2 Pg-C y -1) with respect to a large and uncertain background (123 +/- 4 Pg-C y -1), and

  7. Carbon sinks in temperate forests

    NARCIS (Netherlands)

    Martin, P.H.; Nabuurs, G.J.; Aubinet, M.; Karjalainen, T.; Vine, E.L.; Kinsman, J.; Heath, L.S.

    2001-01-01

    In addition to being scientifically exciting, commercially important, and environmentally essential, temperate forests have also become a key diplomatic item in international climate negotiations as potential sinks for carbon. This review presents the methods used to estimate carbon sequestration, i

  8. Differential effects of sugar maple, red oak, and hemlock tannins on carbon and nitrogen cycling in temperate forest soils.

    Science.gov (United States)

    Talbot, Jennifer M; Finzi, Adrien C

    2008-03-01

    Tannins are abundant secondary chemicals in leaf litter that are hypothesized to slow the rate of soil-N cycling by binding protein into recalcitrant polyphenol-protein complexes (PPCs). We studied the effects of tannins purified from sugar maple, red oak, and eastern hemlock leaf litter on microbial activity and N cycling in soils from northern hardwood-conifer forests of the northeastern US. To create ecologically relevant conditions, we applied tannins to soil at a concentration (up to 2 mg g(-1) soil) typical of mineral soil horizons. Sugar maple tannins increased microbial respiration significantly more than red oak or hemlock tannins. The addition of sugar maple tannins also decreased gross N mineralization by 130% and, depending upon the rate of application, decreased net rates of N mineralization by 50-290%. At low concentrations, the decrease in mineralization appeared to be driven by greater microbial-N immobilization, while at higher concentrations the decrease in mineralization was consistent with the formation of recalcitrant PPCs. Low concentrations of red oak and hemlock tannins stimulated microbial respiration only slightly, and did not significantly affect fluxes of inorganic N in the soil. When applied to soils containing elevated levels of protein, red oak and hemlock tannins decreased N mineralization without affecting rates of microbial respiration, suggesting that PPC formation decreased substrate availability for microbial immobilization. Our results indicate that tannins from all three species form recalcitrant PPCs, but that the degree of PPC formation and its attendant effect on soil-N cycling depends on tannin concentration and the pool size of available protein in the soil.

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

    Science.gov (United States)

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

    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...

  10. The Pyrogenic Carbon Cycle

    Science.gov (United States)

    Bird, Michael I.; Wynn, Jonathan G.; Saiz, Gustavo; Wurster, Christopher M.; McBeath, Anna

    2015-05-01

    Pyrogenic carbon (PyC; includes soot, char, black carbon, and biochar) is produced by the incomplete combustion of organic matter accompanying biomass burning and fossil fuel consumption. PyC is pervasive in the environment, distributed throughout the atmosphere as well as soils, sediments, and water in both the marine and terrestrial environment. The physicochemical characteristics of PyC are complex and highly variable, dependent on the organic precursor and the conditions of formation. A component of PyC is highly recalcitrant and persists in the environment for millennia. However, it is now clear that a significant proportion of PyC undergoes transformation, translocation, and remineralization by a range of biotic and abiotic processes on comparatively short timescales. Here we synthesize current knowledge of the production, stocks, and fluxes of PyC as well as the physical and chemical processes through which it interacts as a dynamic component of the global carbon cycle.

  11. CARBON CYCLING OF TROPICAL-RAIN FOREST AND ITS IMPLICATION%热带雨林的碳循环及其意义

    Institute of Scientific and Technical Information of China (English)

    张洪波; 管东生; 郑淑颖

    2001-01-01

    Because tropical rainforest has a great amount of biomass and primary production, it has a good ability for fixing CO2, which could make the “greenhouse effect” on the earth. The carbon cycling of tropical rainforest has become a hot point for research. This cycling is characterized by short cycling period, giant storage, strong complexity and closing. The carbon cycling of tropical rainforest contains three main processes, such as carbon fixation, returning and recycling, losing and storage. It could enormously influence the global carbon cycling, global change, ecosystem, sustainable development and human life. Great attention should be paid to better management and conservation of tropical forest, and more research work need to be done, as a large amount of carbon is released into the atmosphere that results in many environmental problems due to irrational land use in tropical rainforest.%热带雨林的碳循环及其在全球碳循环中的作用,已经成为当前的热点研究问题。热带雨林的碳循环包括植物的固碳作用、归还作用和再利用、流失及贮存三个过程,并具有周期短、贮存量大、复杂性及封闭性强的特点。而且热带雨林的碳循环对全球碳循环、全球变化、生态系统、环境和可持续发展以及人类本身有巨大影响,但是由于热带林地的土地利用每年造成相当大的碳净释放,并带来一系列的环境问题,因此深入开展对热带雨林的研究,以及合理利用、开发和保护,实现热带雨林的可持续发展意义十分重大。

  12. Leveraging 35 years of Pinus taeda research in the southeastern US to constrain forest carbon cycle predictions: regional data assimilation using ecosystem experiments

    Directory of Open Access Journals (Sweden)

    R. Q. Thomas

    2017-07-01

    Full Text Available Predicting how forest carbon cycling will change in response to climate change and management depends on the collective knowledge from measurements across environmental gradients, ecosystem manipulations of global change factors, and mathematical models. Formally integrating these sources of knowledge through data assimilation, or model–data fusion, allows the use of past observations to constrain model parameters and estimate prediction uncertainty. Data assimilation (DA focused on the regional scale has the opportunity to integrate data from both environmental gradients and experimental studies to constrain model parameters. Here, we introduce a hierarchical Bayesian DA approach (Data Assimilation to Predict Productivity for Ecosystems and Regions, DAPPER that uses observations of carbon stocks, carbon fluxes, water fluxes, and vegetation dynamics from loblolly pine plantation ecosystems across the southeastern US to constrain parameters in a modified version of the Physiological Principles Predicting Growth (3-PG forest growth model. The observations included major experiments that manipulated atmospheric carbon dioxide (CO2 concentration, water, and nutrients, along with nonexperimental surveys that spanned environmental gradients across an 8.6  ×  105 km2 region. We optimized regionally representative posterior distributions for model parameters, which dependably predicted data from plots withheld from the data assimilation. While the mean bias in predictions of nutrient fertilization experiments, irrigation experiments, and CO2 enrichment experiments was low, future work needs to focus modifications to model structures that decrease the bias in predictions of drought experiments. Predictions of how growth responded to elevated CO2 strongly depended on whether ecosystem experiments were assimilated and whether the assimilated field plots in the CO2 study were allowed to have different mortality parameters than the other field

  13. Leveraging 35 years of Pinus taeda research in the southeastern US to constrain forest carbon cycle predictions: regional data assimilation using ecosystem experiments

    Science.gov (United States)

    Quinn Thomas, R.; Brooks, Evan B.; Jersild, Annika L.; Ward, Eric J.; Wynne, Randolph H.; Albaugh, Timothy J.; Dinon-Aldridge, Heather; Burkhart, Harold E.; Domec, Jean-Christophe; Fox, Thomas R.; Gonzalez-Benecke, Carlos A.; Martin, Timothy A.; Noormets, Asko; Sampson, David A.; Teskey, Robert O.

    2017-07-01

    Predicting how forest carbon cycling will change in response to climate change and management depends on the collective knowledge from measurements across environmental gradients, ecosystem manipulations of global change factors, and mathematical models. Formally integrating these sources of knowledge through data assimilation, or model-data fusion, allows the use of past observations to constrain model parameters and estimate prediction uncertainty. Data assimilation (DA) focused on the regional scale has the opportunity to integrate data from both environmental gradients and experimental studies to constrain model parameters. Here, we introduce a hierarchical Bayesian DA approach (Data Assimilation to Predict Productivity for Ecosystems and Regions, DAPPER) that uses observations of carbon stocks, carbon fluxes, water fluxes, and vegetation dynamics from loblolly pine plantation ecosystems across the southeastern US to constrain parameters in a modified version of the Physiological Principles Predicting Growth (3-PG) forest growth model. The observations included major experiments that manipulated atmospheric carbon dioxide (CO2) concentration, water, and nutrients, along with nonexperimental surveys that spanned environmental gradients across an 8.6 × 105 km2 region. We optimized regionally representative posterior distributions for model parameters, which dependably predicted data from plots withheld from the data assimilation. While the mean bias in predictions of nutrient fertilization experiments, irrigation experiments, and CO2 enrichment experiments was low, future work needs to focus modifications to model structures that decrease the bias in predictions of drought experiments. Predictions of how growth responded to elevated CO2 strongly depended on whether ecosystem experiments were assimilated and whether the assimilated field plots in the CO2 study were allowed to have different mortality parameters than the other field plots in the region. We present

  14. Decadal Effects of Elevated CO2 and O3 on Forest Soil Respiration and Belowground Carbon Cycling at Aspen FACE

    Science.gov (United States)

    Talhelm, A. F.; Pregitzer, K. S.; Zak, D. R.; Burton, A. J.

    2014-12-01

    Three northern temperate forest communities in the north-central United States were exposed to factorial combinations of elevated carbon dioxide (CO2) and/or tropospheric ozone (O3) for 11 years, advancing from open-grown seedlings 8 m tall. Here, we report results from measurements of soil respiration that occurred during the experiment from 1999 to 2008. In order to better understand this flux, we compare changes in soil respiration to the effects of CO2 and O3 on net primary productivity (NPP), fine root biomass, and leaf litter production. Elevated CO2 enhanced soil respiration by an average of 28%. This stimulation of soil respiration varied from +19% to +44%, but did not change consistently during the 10 year measurement period (r2 = 0.04). The effect of elevated O3 on soil respiration was dynamic. In year two of the experiment (1999), elevated O3 decreased soil respiration by 7%. However, soil respiration consistently increased through time under elevated O3 (r2 = 0.71) and was 9% greater than under ambient O3 in the final year of the experiment (2008). Overall, elevated O3 had no meaningful effect on soil respiration (+0.3%). The annual effects of elevated CO2 on soil respiration were not correlated with NPP or fine root biomass, but was positively correlated with leaf litter production (r = 0.57). Annual leaf litter production was also related to the annual effects of elevated O3 on soil respiration (r = 0.78), but relationship was tighter between annual O3 effects on NPP and soil respiration (r = 0.83).

  15. The production, storage, and flow of carbon in Amazonian forests

    Science.gov (United States)

    Malhi, Yadvinder; Saatchi, Sassan; Girardin, Cecile; Aragão, Luiz E. O. C.

    The carbon stores and dynamics of tropical forests are the subject of major international scientific and policy attention. Research associated with the Large-Scale Biosphere-Atmosphere Experiment in Amazonia (LBA) has generated substantial advances in our understanding of the cycling of carbon at selected forest sites in Brazilian Amazonia and generated new insights into how these processes may vary across the wider Amazonian region. Here we report on aspects of this new understanding. We present, in particular, a comprehensive synthesis of carbon cycling in three focal LBA sites (Manaus, Tapajõs, and Caxiuanã), drawing on studies of productivity, litterfall, respiration, physiology, and ecosystem fluxes. These studies are placed in the context of the wider Amazonian region by utilizing the results of the Amazon Forest Inventory Network (RAINFOR) and other forest plots. We discuss the basin-wide distribution of forest biomass derived by combining these plots and a suite of satellite data, and examine the dynamics of carbon cycling in the context of regional carbon stores in the forest. Particular attention is drawn to the strong relationship between forest productivity and turnover, which suggests that higher levels of forest productivity increase forest dynamism rather than forest biomass. We conclude by discussing what the scientific priorities should be for a synthetic region-wide understanding of the carbon dynamics and stores of Amazonian forests.

  16. Considering Forest and Grassland Carbon in Land Management

    Science.gov (United States)

    M. Janowiak; W.J. Connelly;   K. Dante-Wood; G.M. Domke; C. Giardina; Z. Kayler; K. Marcinkowski; T. Ontl;   C. Rodriguez-Franco; C. Swanston; C.W. Woodall; M. Buford

    2017-01-01

    Forest and grassland ecosystems in the United States play a critical role in the global carbon cycle, and land management activities influence their ability to absorb and sequester carbon. These ecosystems provide a critical regulating function, offsetting about 12 to 19 percent of the Nation’s annual greenhouse gas emissions. Forests and grasslands are managed for...

  17. Carbon-nitrogen interactions in forest ecosystems; final report

    NARCIS (Netherlands)

    Gundersen, P.; Berg, B.; Currie, W.S.; Dise, N.B.; Emmett, B.A.; Gauci, V.; Holmberg, M.; Kjønaas, O.J.; Mol-Dijkstra, J.P.; Salm, van der C.; Schmidt, I.K.; Tietema, A.; Wessel, W.W.; Vestgarden, L.S.; Akselsson, C.; Vries, de W.; Forsius, M.; Kros, H.; Matzner, E.; Moldan, F.; Nadelhoffer, K.J.; Nilsson, L.O.; Reinds, G.J.; Rosengren, U.; Stuanes, A.O.; Wright, R.F.

    2006-01-01

    This report is a summary of the main results from the EU project 'Carbon' - Nitrogen Interactions in Forest Ecosystems' (CNTER). Since carbon (C) and nitrogen (N) are bound together in organic matter we studied both the effect of N deposition on C cycling in forest ecosystems, and the effect of C ac

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

    Science.gov (United States)

    Coeli M. Hoover

    2011-01-01

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

  19. Hurricane impacts on US forest carbon sequestration

    Science.gov (United States)

    Steven G. McNulty

    2002-01-01

    Recent focus has been given to US forests as a sink for increases in atmospheric carbon dioxide. Current estimates of US Forest carbon sequestration average approximately 20 Tg (i.e. 1012 g) year. However, predictions of forest carbon sequestration often do not include the influence of hurricanes on forest carbon storage. Intense hurricanes...

  20. Lianas reduce carbon accumulation and storage in tropical forests.

    Science.gov (United States)

    van der Heijden, Geertje M F; Powers, Jennifer S; Schnitzer, Stefan A

    2015-10-27

    Tropical forests store vast quantities of carbon, account for one-third of the carbon fixed by photosynthesis, and are a major sink in the global carbon cycle. Recent evidence suggests that competition between lianas (woody vines) and trees may reduce forest-wide carbon uptake; however, estimates of the impact of lianas on carbon dynamics of tropical forests are crucially lacking. Here we used a large-scale liana removal experiment and found that, at 3 y after liana removal, lianas reduced net above-ground carbon uptake (growth and recruitment minus mortality) by ∼76% per year, mostly by reducing tree growth. The loss of carbon uptake due to liana-induced mortality was four times greater in the control plots in which lianas were present, but high variation among plots prevented a significant difference among the treatments. Lianas altered how aboveground carbon was stored. In forests where lianas were present, the partitioning of forest aboveground net primary production was dominated by leaves (53.2%, compared with 39.2% in liana-free forests) at the expense of woody stems (from 28.9%, compared with 43.9%), resulting in a more rapid return of fixed carbon to the atmosphere. After 3 y of experimental liana removal, our results clearly demonstrate large differences in carbon cycling between forests with and without lianas. Combined with the recently reported increases in liana abundance, these results indicate that lianas are an important and increasing agent of change in the carbon dynamics of tropical forests.

  1. ROE Carbon Storage - Forest Biomass

    Data.gov (United States)

    U.S. Environmental Protection Agency — This polygon dataset depicts the density of forest biomass in counties across the United States, in terms of metric tons of carbon per square mile of land area....

  2. Characteristics of water and carbon balance in moso bamboo forests

    Science.gov (United States)

    Kume, T.; Laplace, S.; Tseng, H.; Hsieh, Y.; Wey, T.; Komatsu, H.

    2013-12-01

    Water and carbon cycles in mountainous areas can have considerable impacts on our available nature resources such as water resources and timber production. Thus, it is indispensable to clarify the difference of water and carbon balances between different types of forested ecosystems. Recently, bamboo forests have been expanding by replacing surrounding vegetation such as coniferous and broad-leaved forests in eastern Asian countries. It has been speculated that the replacements by bamboo forests could alter the vegetation water and carbon cycles. However, our knowledge for the bamboo forests was still limited due to lack of applicable methodology based on a field measurement. To clarify the potential impacts of bamboo expansion on water and carbon cycles, our previous study established optimal and effective design for assessing bamboo forest water use (ie, transpiration) based on sap flux measurements. Using the method, we quantified stand-scale transpiration in bamboo forests and coniferous forests in Taiwan. Consequently, we found significantly larger transpiration in bamboo forests compared with those of surrounding vegetation due to larger canopy conductance in bamboo forests. The unique characteristics of the water use accompanied larger carbon assimilation and soil CO2 efflux in bamboo forests.

  3. Carbon Budget of Russian Forests

    Directory of Open Access Journals (Sweden)

    A. Z. Shvidenko

    2014-02-01

    Full Text Available Net Ecosystem Carbon Balance (NECB of Russian forests for 2007–2009 is presented based on consistent application of applied systems analysis and modern information technologies. Use of landscape-ecosystem approach resulted in the NECB at 546±120 Tg C year–1, or 66±15 g C m–2 year–1. There is a substantial difference between the NECB of European and Asian parts, as well as the clear zonal gradients within these geographical regions. While the total carbon sink is high, large forest areas, particularly on permafrost, serve as a carbon source. The ratio between net primary production and soil heterotrophic respiration, together with natural and human-induced disturbances are major drivers of the magnitude and spatial distribution of the NECB of forest ecosystems. Using the Bayesian approach, mutual constraints of results that are obtained by independent methods enable to decrease uncertainties of the final result.

  4. The Carbon Cycle: Implications for Climate Change and Congress

    Science.gov (United States)

    2008-03-13

    from human activities.4 Methane, black carbon, and organic carbon pollution are also part of the carbon cycle and have roles in human-induced climate...recovery and concludes that tropical regions dominated by rainforests or other forest types are a net source of carbon to the atmosphere. 27 However, a...Some model simulations suggest that the Southern Ocean around Antarctica accounts for nearly half of the net air -sea flux of anthropogenic carbon.43

  5. Spatial patterns of ecosystem carbon residence time in Chinese forests

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Capacity of carbon sequestration in forest ecosystem largely depends on the trend of net primary production (NPP) and the length of ecosystem carbon residence time. Retrieving spatial patterns of ecosystem carbon residence time is important and necessary for accurately predicting regional carbon cycles in the future. In this study, a data-model fusion method that combined a process-based regional carbon model (TECO-R) with various ground-based ecosystem observations (NPP, biomass, and soil organic carbon) and auxiliary data sets (NDVI, meteorological data, and maps of vegetation and soil texture) was applied to estimate spatial patterns of ecosystem carbon residence time in Chinese forests at steady state. In the data-model fusion, the genetic algorithm was used to estimate the optimal model parameters related with the ecosystem carbon residence time by minimizing total deviation between modeled and observed values. The results indicated that data-model fusion technology could effectively retrieve model parameters and simulate carbon cycling processes for Chinese forest ecosystems. The estimated carbon residence times were highly heterogenous over China, with most of regions having values between 24 and 70 years. The deciduous needleleaf forest and the evergreen needleleaf forest had the highest averaged carbon residence times (73.8 and 71.3 years, respectively), the mixed forest and the deciduous broadleaf forest had moderate values (38.1 and 37.3 years, respectively), and the evergreen broadleaf forest had the lowest value (31.7 years). The averaged carbon residence time of forest ecosystems in China was 57.8 years.

  6. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to

  7. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to thi

  8. Carbon budgets and carbon sequestration potential of Indian forests

    NARCIS (Netherlands)

    Kaul, M.

    2010-01-01

    Keywords: Carbon uptake, Forest biomass, Bioenergy, Land use change, Indian forests, Deforestation, Afforestation, Rotation length, Trees outside forests. Global climate change is a widespread and growing concern that has led to extensive international discussions and negotiations. Responses to thi

  9. Mirador - Carbon Cycle and Ecosystems

    Data.gov (United States)

    National Aeronautics and Space Administration — Earth Science data access made simple. This Focus Area deals with the cycling of carbon in reservoirs and ecosystems as it changes naturally, is changed by humans,...

  10. US Forest Service Forest Carbon Stocks Contiguous United States

    Data.gov (United States)

    US Forest Service, Department of Agriculture — Through application of a nearest-neighbor imputation approach, mapped estimates of forest carbon density were developed for the contiguous United States using the...

  11. The relative contributions of forest growth and areal expansion to forest biomass carbon sinks in China

    Directory of Open Access Journals (Sweden)

    P. Li

    2015-06-01

    Full Text Available Forests play a leading role in regional and global terrestrial carbon (C cycles. Changes in C sequestration within forests can be attributed to areal expansion (increase in forest area and forest growth (increase in biomass density. Detailed assessment of the relative contributions of areal expansion and forest growth to C sinks is crucial to reveal the mechanisms that control forest C sinks and is helpful for developing sustainable forest management policies in the face of climate change. Using the Forest Identity concept and forest inventory data, this study quantified the spatial and temporal changes in the relative contributions of forest areal expansion and increased biomass growth to China's forest C sinks from 1977 to 2008. Over the last 30 years, the areal expansion of forests was a larger contributor to C sinks than forest growth for all forests and planted forests in China (74.6 vs. 25.4 % for all forests, and 62.4 vs. 37.8 % for plantations. However, for natural forests, forest growth made a larger contribution than areal expansion (60.4 vs. 39.6 %. The relative contribution of forest growth of planted forests showed an increasing trend from an initial 25.3 to 61.0 % in the later period of 1998 to 2003, but for natural forests, the relative contributions were variable without clear trends owing to the drastic changes in forest area and biomass density over the last 30 years. Our findings suggest that afforestation can continue to increase the C sink of China's forests in the future subject to persistently-increasing forest growth after establishment of plantation.

  12. Drought and ecosystem carbon cycling

    NARCIS (Netherlands)

    Molen, van der M.K.; Dolman, A.J.; Ciais, P.; Eglin, T.; Gobron, N.; Law, B.E.; Meir, P.; Peters, W.; Philips, O.L.; Hurk, van den B.J.J.M.; Jeu, M.; Kruijt, B.; Teuling, A.J.; Werf, van der G.R.; Wang, G.

    2011-01-01

    Drought as an intermittent disturbance of the water cycle interacts with the carbon cycle differently than the ‘gradual’ climate change. During drought plants respond physiologically and structurally to prevent excessive water loss according to species-specific water use strategies. This has consequ

  13. Multiplying Forest Garden Systems with biochar based organic fertilization for high carbon accumulation, improved water storage, nutrient cycling, and increased food diversity and farm productivity

    Science.gov (United States)

    Schmidt, Hans-Peter; Pandit, Bishnu Hari; Lucht, Wolfgang; Gerten, Dieter; Kammann, Claudia

    2017-04-01

    On abandoned, erosion prone terraces in the middle hills of Nepal, 86 participating farmer families planted >25,000 mixed trees in 2015/16. Since it was convincingly demonstrated by more than 20 field trials in this region that this was the most plant-growth promoting method, all trees were planted with farmer-made organic biochar-based fertilizer. Planting pits were mulched with rice straw and were pipe irrigated from newly established water retention ponds during the 7 months of the dry season. A peer control system of farmer triads ensured an efficient maintenance of the plantations. Tree survival rate was above 80% after one year compared to below 50% on average for countrywide forestation projects over the last 30 years. In between the young Cinnamon, Moringa, Mulberry, Lemon, Michelia, Paulownia, nut and other trees, other secondary crops were cultivated such as ginger, turmeric, black beans, onions, lentils, all with organic biochar-based fertilizer and mulching. The objective of this forest garden project was to establish robust social-agronomic systems that can be multiplied from village to village for increasing soil fertility, protecting abandoned terraces from erosion, replenishing natural water resources, generating a stable income with climate-smart agriculture, as well as capturing and sequestering atmospheric carbon. The initial financing of the set-up of the forest garden systems (tree nursery, plantation, preparation of organic biochar based fertilizer, mulching materials, building of irrigation pits and pipe irrigation system, and general maintenance) was covered by carbon credits paid in advance by the international community in the form of a monthly carbon compensation subscription. All planted trees are GIS inventoried and the yearly biomass carbon uptake will be calculated as an average value of the first ten years of tree growth. The 25,000 mixed trees accumulated the equivalent of 350 t CO2 per year (10 years total C-accumulation divided by

  14. Interactions between land use change and carbon cycle feedbacks: Land Use and Carbon Cycle Feedbacks

    Energy Technology Data Exchange (ETDEWEB)

    Mahowald, Natalie M. [Cornell Univ., Ithaca, NY (United States); Randerson, James T. [Univ. of California, Irvine, CA (United States); Lindsay, Keith [National Center for Atmospheric Research, Boulder, CO (United States); Munoz, Ernesto [National Center for Atmospheric Research, Boulder, CO (United States); Doney, Scott C. [Woods Hole Oceanographic Inst., Woods Hole, MA (United States); Lawrence, Peter [National Center for Atmospheric Research, Boulder, CO (United States); Schlunegger, Sarah [Cornell Univ., Ithaca, NY (United States); Princeton Univ., NJ (United States); Ward, Daniel S. [Cornell Univ., Ithaca, NY (United States); Princeton Univ., NJ (United States); Lawrence, David [National Center for Atmospheric Research, Boulder, CO (United States); Hoffman, Forrest M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-23

    We explore the role of human land use and land cover change (LULCC) in modifying the terrestrial carbon budget in simulations forced by Representative Concentration Pathway 8.5, extended to year 2300 by using the Community Earth System Model, . Overall, conversion of land (e.g., from forest to croplands via deforestation) results in a model-estimated, cumulative carbon loss of 490 Pg C between 1850 and 2300, larger than the 230 Pg C loss of carbon caused by climate change over this same interval. The LULCC carbon loss is a combination of a direct loss at the time of conversion and an indirect loss from the reduction of potential terrestrial carbon sinks. Approximately 40% of the carbon loss associated with LULCC in the simulations arises from direct human modification of the land surface; the remaining 60% is an indirect consequence of the loss of potential natural carbon sinks. Because of the multicentury carbon cycle legacy of current land use decisions, a globally averaged amplification factor of 2.6 must be applied to 2015 land use carbon losses to adjust for indirect effects. This estimate is 30% higher when considering the carbon cycle evolution after 2100. Most of the terrestrial uptake of anthropogenic carbon in the model occurs from the influence of rising atmospheric CO2 on photosynthesis in trees, and thus, model-projected carbon feedbacks are especially sensitive to deforestation.

  15. Africa and the global carbon cycle

    Directory of Open Access Journals (Sweden)

    Denning A Scott

    2007-03-01

    Full Text Available Abstract The African continent has a large and growing role in the global carbon cycle, with potentially important climate change implications. However, the sparse observation network in and around the African continent means that Africa is one of the weakest links in our understanding of the global carbon cycle. Here, we combine data from regional and global inventories as well as forward and inverse model analyses to appraise what is known about Africa's continental-scale carbon dynamics. With low fossil emissions and productivity that largely compensates respiration, land conversion is Africa's primary net carbon release, much of it through burning of forests. Savanna fire emissions, though large, represent a short-term source that is offset by ensuing regrowth. While current data suggest a near zero decadal-scale carbon balance, interannual climate fluctuations (especially drought induce sizeable variability in net ecosystem productivity and savanna fire emissions such that Africa is a major source of interannual variability in global atmospheric CO2. Considering the continent's sizeable carbon stocks, their seemingly high vulnerability to anticipated climate and land use change, as well as growing populations and industrialization, Africa's carbon emissions and their interannual variability are likely to undergo substantial increases through the 21st century.

  16. Forest liming increases forest floor carbon and nitrogen stocks in a mixed hardwood forest.

    Science.gov (United States)

    Melvin, April M; Lichstein, Jeremy W; Goodale, Christine L

    2013-12-01

    In acid-impacted forests, decreased soil pH and calcium (Ca) availability have the potential to influence biotic and abiotic controls on carbon (C) and nitrogen (N) cycling. We investigated the effects of liming on above- and belowground C and N pools and fluxes 19 years after lime addition to the Woods Lake Watershed, Adirondack Park, New York, USA. Soil pH and exchangeable Ca remained elevated in the forest floor and upper mineral soil of limed areas. Forest floor C and N stocks were significantly larger in limed plots (68 vs. 31 Mg C/ha, and 3.0 vs. 1.5 Mg N/ha), resulting from a larger mass of Oa material. Liming reduced soil basal respiration rates by 17% and 43% in the Oe and Oa horizons, respectively. Net N mineralization was significantly lower in the limed soils for both forest floor horizons. Additional measurements of forest floor depth outside of our study plots, but within the treatment and control subcatchments also showed a deeper forest floor in limed areas; however, the mean depth of limed forest floor was 5 cm shallower than that observed in our study plots. Using a differential equation model of forest floor C dynamics, we found that liming effects on C fluxes measured within our study plots could explain the small observed increase in the Oe C stock but were not large enough to explain the increase in the Oa. Our catchment-wide assessment of forest floor depth, however, indicates that our plot analysis may be an overestimate of ecosystem-scale C and N stocks. Our results suggest that the mechanisms identified in our study, primarily liming-induced reduction in decomposition rates, may account for much of the observed increase in forest floor C. These findings emphasize the importance of understanding of the effects of liming in hardwood forests, and the long-term impacts of acid deposition on forest C and N uptake and retention.

  17. Closing carbon cycles

    NARCIS (Netherlands)

    Patel, Martin

    2001-01-01

    Fossil fuels are used as raw materials for the manufacture of synthetic organic materials, e.g. plastics, fibres, synthetic rubber, paints, solvents, fertilisers, surfactants, lubricants and bitumen. Since fossil carbon is embodied in these products they may be particularly relevant to climate ch

  18. Branchfall dominates annual carbon flux across lowland Amazonian forests

    Science.gov (United States)

    Marvin, David C.; Asner, Gregory P.

    2016-09-01

    Tropical forests play an important role in the global carbon cycle, but knowledge of interannual variation in the total tropical carbon flux and constituent carbon pools is highly uncertain. One such pool, branchfall, is an ecologically important dynamic with links to nutrient cycling, forest productivity, and drought. Identifying and quantifying branchfall over large areas would reveal the role of branchfall in carbon and nutrient cycling. Using data from repeat airborne light detection and ranging campaigns across a wide array of lowland Amazonian forest landscapes totaling nearly 100 000 ha, we find that upper canopy gaps—driven by branchfall—are pervasive features of every landscape studied, and are seven times more frequent than full tree mortality. Moreover, branchfall comprises a major carbon source on a landscape basis, exceeding that of tree mortality by 21%. On a per hectare basis, branchfall and tree mortality result in 0.65 and 0.72 Mg C ha-1 yr-1 gross source of carbon to the atmosphere, respectively. Reducing uncertainties in annual gross rates of tropical forest carbon flux, for example by incorporating large-scale branchfall dynamics, is crucial for effective policies that foster conservation and restoration of tropical forests. Additionally, large-scale branchfall mapping offers ecologists a new dimension of disturbance monitoring and potential new insights into ecosystem structure and function.

  19. Carbon cycle makeover

    DEFF Research Database (Denmark)

    Canfield, Donald Eugene; Kump, Lee R.

    2013-01-01

    remaining in sediments after respiration leave a residual of oxygen in the atmosphere. The source of oxygen to the atmosphere represented by organic matter burial is balanced by oxygen sinks associated with rock weathering and chemical reaction with volcanic gases. This is the long-term carbon and oxygen......In 1845, the French chemist and mining engineer Jacques-Joseph Ebelman figured out why Earth's atmosphere contains oxygen (1). Oxygen is produced by plants during photosynthesis, but almost all of this oxygen is used again in respiration. Ebelman reasoned that small amounts of organic matter...

  20. SUSTAINING CARBON SINK POTENTIALS IN TROPICAL FOREST ...

    African Journals Online (AJOL)

    HP

    Key words: Carbon sequestration, tropical forest, deforestation, conservation. INTRODUCTION ... to complex organic molecules which are then used by the whole plant. ..... Disturbances and structural development of natural forest ecosystems.

  1. Climate extremes and the carbon cycle (Invited)

    Science.gov (United States)

    Reichstein, M.; Bahn, M.; Ciais, P.; Mahecha, M. D.; Seneviratne, S. I.; Zscheischler, J.

    2013-12-01

    The terrestrial biosphere is a key component of the global carbon cycle and its carbon balance is strongly influenced by climate. Ongoing environmental changes are thought to increase global terrestrial carbon uptake. But evidence is mounting that rare climate extremes can lead to a decrease in ecosystem carbon stocks and therefore have the potential to negate the expected increase in terrestrial carbon uptake. Here we explore the mechanisms and impacts of climate extremes on the terrestrial carbon cycle, and propose a pathway to improve our understanding of present and future impacts of climate extremes on the terrestrial carbon budget. In addition to direct impact on the carbon fluxes of photosynthesis and respiration via extreme temperature and (or) drought, effects of extreme events may also lead to lagged responses, such as wildfires triggered by heat waves and droughts, or pest and pathogen outbreaks following wind-throw caused by heavy storms, reduced plant health due to drought stress or due to less frequent cold extremes in presently cold regions. One extreme event can potentially override accumulated previous carbon sinks, as shown by the Western European 2003 heat wave.. Extreme events have the potential to affect the terrestrial ecosystem carbon balance through a single factor, or as a combination of factors. Climate extremes can cause carbon losses from accumulated stocks, as well as long-lasting impacts on (e.g. lagged effects) on plant growth and mortality, extending beyond the duration of the extreme event itself. The sensitivity of terrestrial ecosystems and their carbon balance to climate change and extreme events varies according to the type of extreme, the climatic region, the land cover, and the land management. Extreme event impacts are very relevant in forests due to the importance of lagged and memory effects on tree growth and mortality, the longevity of tree species, the large forest carbon stocks and their vulnerability, as well as the

  2. Forest carbon uptake in North America's aging temperate deciduous forests: A data-theory-model mismatch?

    Science.gov (United States)

    Gough, C. M.; Curtis, P.; Bond-Lamberty, B. P.; Hardiman, B. S.; Scheuermann, C. M.; Nave, L. E.; Nadelhoffer, K. J.

    2015-12-01

    Century-old temperate deciduous forests in the US upper Midwest and Northeast power much of North America's terrestrial carbon sink, but these forests' carbon uptake capacity is expected to soon decline. But will this really happen? We marshal empirical data and ecological theory to show that declines in carbon uptake are not imminent in regrown temperate deciduous forests during coming decades, despite long-held assumptions and modeling results that predict declining carbon uptake during middle stages of ecosystem development. Age and production data for temperate deciduous forests, synthesized from published literature, do not provide evidence for declining net primary and ecosystem production (NPP and NEP, respectively) within the age-range most regional forests will occupy over the next half-century. Ecological theory suggests a mechanism for sustained carbon uptake in the region's aging forests in which high-frequency, low-severity disturbances maintain NPP and NEP by increasing ecosystem complexity. This theoretical model is supported by observations from the Forest Accelerated Succession Experiment in Michigan, USA, but such mechanisms sustaining production in old forests are not broadly represented in ecosystem models. Ecosystems experiencing low-frequency, high-severity disturbances that simplify ecosystem complexity do exhibit declining production during middle stages of succession, but we suggest that such scenarios have exerted a disproportionate influence on prevailing modeling and ecological assumptions regarding age-related declines in forest production. We conclude that there is wide ecological space for forests to sustain high rates of carbon uptake during middle stages of ecosystem development, and that advancing mechanistic understanding of long-term forest carbon cycle dynamics is essential to modeling the continent's future carbon sink strength.

  3. Quality of urban forest carbon credits

    Science.gov (United States)

    Neelam C. Poudyala; Jacek P. Siry; J.M. Bowker

    2011-01-01

    While the urban forest is considered an eligible source of carbon offset credits, little is known about its market potential and the quality aspects of the credits. As credit suppliers increase in number and credit buyers become more interested in purchasing carbon credits, it is unclear whether and how urban forest carbon credits can perform relative to the other...

  4. Restoring forest structure and process stabilizes forest carbon in wildfire-prone southwestern ponderosa pine forests

    Science.gov (United States)

    Matthew D. Hurteau; Shuang Liang; Katherine L. Martin; Malcolm P. North; George W. Koch; Bruce A. Hungate

    2016-01-01

    Changing climate and a legacy of fire-exclusion have increased the probability of high-severity wildfire, leading to an increased risk of forest carbon loss in ponderosa pine forests in the southwestern USA. Efforts to reduce high-severity fire risk through forest thinning and prescribed burning require both the removal and emission of carbon from these forests, and...

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

    Science.gov (United States)

    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.

  6. A tree-ring perspective on the terrestrial carbon cycle.

    Science.gov (United States)

    Babst, Flurin; Alexander, M Ross; Szejner, Paul; Bouriaud, Olivier; Klesse, Stefan; Roden, John; Ciais, Philippe; Poulter, Benjamin; Frank, David; Moore, David J P; Trouet, Valerie

    2014-10-01

    Tree-ring records can provide valuable information to advance our understanding of contemporary terrestrial carbon cycling and to reconstruct key metrics in the decades preceding monitoring data. The growing use of tree rings in carbon-cycle research is being facilitated by increasing recognition of reciprocal benefits among research communities. Yet, basic questions persist regarding what tree rings represent at the ecosystem level, how to optimally integrate them with other data streams, and what related challenges need to be overcome. It is also apparent that considerable unexplored potential exists for tree rings to refine assessments of terrestrial carbon cycling across a range of temporal and spatial domains. Here, we summarize recent advances and highlight promising paths of investigation with respect to (1) growth phenology, (2) forest productivity trends and variability, (3) CO2 fertilization and water-use efficiency, (4) forest disturbances, and (5) comparisons between observational and computational forest productivity estimates. We encourage the integration of tree-ring data: with eddy-covariance measurements to investigate carbon allocation patterns and water-use efficiency; with remotely sensed observations to distinguish the timing of cambial growth and leaf phenology; and with forest inventories to develop continuous, annually-resolved and long-term carbon budgets. In addition, we note the potential of tree-ring records and derivatives thereof to help evaluate the performance of earth system models regarding the simulated magnitude and dynamics of forest carbon uptake, and inform these models about growth responses to (non-)climatic drivers. Such efforts are expected to improve our understanding of forest carbon cycling and place current developments into a long-term perspective.

  7. Detrital carbon pools in temperate forests: magnitude and potential for landscape-scale assessment

    Science.gov (United States)

    John Bradford; Peter Weishampel; Marie-Louise Smith; Randall Kolka; Richard A. Birdsey; Scott V. Ollinger; Michael G. Ryan

    2009-01-01

    Reliably estimating carbon storage and cycling in detrital biomass is an obstacle to carbon accounting. We examined carbon pools and fluxes in three small temperate forest landscapes to assess the magnitude of carbon stored in detrital biomass and determine whether detrital carbon storage is related to stand structural properties (leaf area, aboveground biomass,...

  8. Forest disturbance and North American carbon flux

    Science.gov (United States)

    S. N. Goward; J. G. Masek; W. Cohen; G. Moisen; G. J. Collatz; S. Healey; R. A. Houghton; C. Huang; R. Kennedy; B. Law; S. Powell; D. Turner; M. A. Wulder

    2008-01-01

    North America's forests are thought to be a significant sink for atmospheric carbon. Currently, the rate of sequestration by forests on the continent has been estimated at 0.23 petagrams of carbon per year, though the uncertainty about this estimate is nearly 50%. This offsets about 13% of the fossil fuel emissions from the continent [Pacala et al., 2007]. However...

  9. Forest management techniques for carbon dioxide storage

    Energy Technology Data Exchange (ETDEWEB)

    Fujimori, Takao [Forestry and Forest Products Research Inst., Tsukuba, Ibaraki (Japan)

    1993-12-31

    In the global ecosystem concerning carbon dioxide content in the atmosphere, the forest ecosystem plays an important role. In effect, the ratio of forest biomass to total terrestrial biomass is about 90%, and the ratio of carbon stored in the forest biomass to that in the atmosphere is two thirds. When soils and detritus of forests are added, there is more C stored in forests than in the atmosphere, about 1.3 times or more. Thus, forests can be regarded as the great holder of C on earth. If the area of forest land on the earth is constantly maintained and forests are in the climax stage, the uptake of C and the release of C by and from the forests will balance. In this case, forests are neither sinks nor sources of CO{sub 2} although they store a large amount of C. However, when forests are deforested, they become a source of C; through human activities, forests have become a source of C. According to a report by the IPCC, 1.6{+-}1.2 PgC is annually added to the atmosphere by deforestation. According to the FAO (1992), the area of land deforested annually in the tropics from 1981 to 1990 was 16.9 x 10{sup 6} ha. This value is nearly half the area of Japanese land. The most important thing for the CO{sub 2} environment concerning forests is therefore how to reduce deforestation and to successfully implement a forestation or reforestation.

  10. Ecosystem carbon storage and partitioning in a tropical seasonal forest in Southwestern China

    DEFF Research Database (Denmark)

    Lü, Xiao-Tao; Yin, Jiang-Xia; Jepsen, Martin Rudbeck

    2010-01-01

    Tropical forests play an important role in the global carbon cycle. Despite an increasing number of studies have addressed carbon storage in tropical forests, the regional variation in such storage remains poorly understood. Uncertainty about how much carbon is stored in tropical forests...... is an important limitation for regional-scale estimates of carbon fluxes and improving these estimates requires extensive field studies of both above- and belowground stocks. In order to assess the carbon pools of a tropical seasonal forest in Asia, total ecosystem carbon storage was investigated in Xishuangbanna......, SW China. Averaged across three 1 ha plots, the total carbon stock of the forest ecosystem was 303 t C ha-1. Living tree carbon stocks (both above- and belowground) ranged from 163 to 258 t C ha-1. The aboveground biomass C pool is comparable to the Dipterocarp forests in Sumatra but lower than those...

  11. Forest management strategies for reducing carbon emissions, the French case

    Science.gov (United States)

    Valade, Aude; Luyssaert, Sebastiaan; Bellassen, Valentin; Vallet, Patrick; Martin, Manuel

    2015-04-01

    International agreements now recognize the role of forest in the mitigation of climate change through the levers of in-situ sequestration, storage in products and energy and product substitution. These three strategies of carbon management are often antagonistic and it is still not clear which strategy would have the most significant impact on atmospheric carbon concentrations. With a focus on France, this study compares several scenarios of forest management in terms of their effect on the overall carbon budget from trees to wood-products. We elaborated four scenarios of forest management that target different wood production objectives. One scenario is 'Business as usual' and reproduces the current forest management and wood production levels. Two scenarios target an increase in bioenergy wood production, with either long-term or short-term goals. One scenario aims at increasing the production of timber for construction. For this, an empirical regression model was developed building on the rich French inventory database. The model can project the current forest resource at a time horizon of 20 years for characteristic variables diameter, standing volume, above-ground biomass, stand age. A simplified life-cycle analysis provides a full carbon budget for each scenario from forest management to wood use and allows the identification of the scenario that most reduces carbon emissions.

  12. Estimating carbon stock in secondary forests

    DEFF Research Database (Denmark)

    Breugel, Michiel van; Ransijn, Johannes; Craven, Dylan

    2011-01-01

    Secondary forests are a major terrestrial carbon sink and reliable estimates of their carbon stocks are pivotal for understanding the global carbon balance and initiatives to mitigate CO2 emissions through forest management and reforestation. A common method to quantify carbon stocks in forests...... is the use of allometric regression models to convert forest inventory data to estimates of aboveground biomass (AGB). The use of allometric models implies decisions on the selection of extant models or the development of a local model, the predictor variables included in the selected model, and the number...... of trees and species for destructive biomass measurements. We assess uncertainties associated with these decisions using data from 94 secondary forest plots in central Panama and 244 harvested trees belonging to 26 locally abundant species. AGB estimates from species-specific models were used to assess...

  13. CARBON BALANCE OF FOREST ECOSYSTEMS UNDER GLOBAL WARMING: LANDSCAPE-ECOLOGICAL PREDICTIVE MODELING

    Directory of Open Access Journals (Sweden)

    Erland Kolomyts

    2011-01-01

    Full Text Available This paper presents the results of application of landscape-ecological methods for evaluation of biotic regulation of the carbon cycle in forest ecosystems. Methods for constructing analytical and cartographic empirical-statistical models for identification of forest associations and zonal/regional types of forest formations capable of stabilizing the continental biosphere under changing climate are described. Possible biotic regulation of the carbon cycle under known scenarios of future greenhouse warming is suggested. The maps on the carbon content and its changes in the forests of the Oka river basin are presented.

  14. Forest biomass carbon stocks and variation in Tibet's carbon-dense forests from 2001 to 2050.

    Science.gov (United States)

    Sun, Xiangyang; Wang, Genxu; Huang, Mei; Chang, Ruiying; Ran, Fei

    2016-10-05

    Tibet's forests, in contrast to China's other forests, are characterized by primary forests, high carbon (C) density and less anthropogenic disturbance, and they function as an important carbon pool in China. Using the biomass C density data from 413 forest inventory sites and a spatial forest age map, we developed an allometric equation for the forest biomass C density and forest age to assess the spatial biomass C stocks and variation in Tibet's forests from 2001 to 2050. The results indicated that the forest biomass C stock would increase from 831.1 Tg C in 2001 to 969.4 Tg C in 2050, with a net C gain of 3.6 Tg C yr(-1) between 2001 and 2010 and a decrease of 1.9 Tg C yr(-1) between 2040 and 2050. Carbon tends to allocate more in the roots of fir forests and less in the roots of spruce and pine forests with increasing stand age. The increase of the biomass carbon pool does not promote significant augmentation of the soil carbon pool. Our findings suggest that Tibet's mature forests will remain a persistent C sink until 2050. However, afforestation or reforestation, especially with the larger carbon sink potential forest types, such as fir and spruce, should be carried out to maintain the high C sink capacity.

  15. Climate and the Carbon Cycle

    Science.gov (United States)

    Manley, Jim

    2017-04-01

    Climate and the Carbon Cycle EOS3a Science in tomorrow's classroom Students, like too much of the American public, are largely unaware or apathetic to the changes in world climate and the impact that these changes have for life on Earth. A study conducted by Michigan State University and published in 2011 by Science Daily titled 'What carbon cycle? College students lack scientific literacy, study finds'. This study relates how 'most college students in the United States do not grasp the scientific basis of the carbon cycle - an essential skill in understanding the causes and consequences of climate change.' The study authors call for a new approach to teaching about climate. What if teachers better understood vital components of Earth's climate system and were able to impart his understanding to their students? What if students based their responses to the information taught not on emotion, but on a deeper understanding of the forces driving climate change, their analysis of the scientific evidence and in the context of earth system science? As a Middle School science teacher, I have been given the opportunity to use a new curriculum within TERC's EarthLabs collection, Climate and the Carbon Cycle, to awaken those brains and assist my students in making personal lifestyle choices based on what they had learned. In addition, with support from TERC and The University of Texas Institute for Geophysics I joined others to begin training other teachers on how to implement this curriculum in their classrooms to expose their students to our changing climate. Through my poster, I will give you (1) a glimpse into the challenges faced by today's science teachers in communicating the complicated, but ever-deepening understanding of the linkages between natural and human-driven factors on climate; (2) introduce you to a new module in the EarthLabs curriculum designed to expose teachers and students to global scientific climate data and instrumentation; and (3) illustrate how

  16. Rethinking forest carbon assessments to account for policy institutions

    Science.gov (United States)

    Macintosh, Andrew; Keith, Heather; Lindenmayer, David

    2015-10-01

    There has been extensive debate about whether the sustainable use of forests (forest management aimed at producing a sustainable yield of timber or other products) results in superior climate outcomes to conservation (maintenance or enhancement of conservation values without commercial harvesting). Most of the relevant research has relied on consequential life-cycle assessment (LCA), with the results tending to show that sustainable use has lower net greenhouse-gas (GHG) emissions than conservation in the long term. However, the literature cautions that results are sensitive to forest- and market-related contextual factors: the carbon density of the forests, silvicultural and wood processing practices, and the extent to which wood products and forest bioenergy displace carbon-intensive alternatives. Depending on these issues, conservation can be better for the climate than sustainable use. Policy institutions are another key contextual factor but, so far, they have largely been ignored. Using a case study on the Southern Forestry Region (SFR) of New South Wales (NSW), Australia, we show how policy institutions can affect the assessed outcomes from alternative forest management strategies. Our results highlight the need for greater attention to be paid to policy institutions in forest carbon research.

  17. Carbon Emission Reduction Potential through Sustainable Forest Management in Forest Concession of PT Salaki Summa Sejahtera, Province of West Sumatera

    Directory of Open Access Journals (Sweden)

    Iwan Hilwan

    2012-12-01

    Full Text Available A management unit (MU of a forest concession holder implementing the sustainable forest management (SFM principles, could be involved in reducing Emmission from Reforestation and Forest Degradation (REDD+ and carbon trading project. The fact the strategic in implementing the REDD+ and carbon trading in MU level is still lack of pilot project and methodology. Therefore, some scenarios must be developed and tested to find out the best potential of carbon credit in MU level. The objectives of the research were: to calculate carbon credit in some SFM scenarios, to analyze of carbon trading project feasibility, and to determine carbon stock recovery period of logged over area (LOA. The result revealed that carbon stock and carbon credit of LOA was affected by timber cutting intensity.  The 6th scenario with lowest annual allowable cutting (AAC obtained greater carbon credit and profit coming from timber harvesting income and carbon trading. In other hand, this scenario has shortest duration of carbon stock recovery period (27 years and shorter than its cutting cycle.  In this case, the MU has to recalculate and to decrease its AAC to have highest benefits from carbon trading in the same cutting cycle period.  It will provide double benefits from carbon trading, those are contribution in achieving the SFM purposes (production, ecology, social and climate change mitigation.Keywords: sustainable forest management, AAC, carbon stocks, recovery period, carbon trading

  18. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    NARCIS (Netherlands)

    Wagner, Fabien H.; Hérault, Bruno; Bonal, Damien; Stahl, Clément; Anderson, Liana O.; Baker, Timothy R.; Becker, Gabriel Sebastian; Beeckman, Hans; Boanerges Souza, Danilo; Botosso, Paulo Cesar; Bowman, David M.J.S.; Bräuning, Achim; Brede, Benjamin; Brown, Foster Irving; Camarero, Jesus Julio; Camargo, Plínio Barbosa; Cardoso, Fernanda C.G.; Carvalho, Fabrício Alvim; Castro, Wendeson; Chagas, Rubens Koloski; Chave, Jérome; Chidumayo, Emmanuel N.; Clark, Deborah A.; Costa, Flavia Regina Capellotto; Couralet, Camille; Silva Mauricio, Da Paulo Henrique; Dalitz, Helmut; Castro, De Vinicius Resende; Freitas Milani, De Jaçanan Eloisa; Oliveira, De Edilson Consuelo; Souza Arruda, De Luciano; Devineau, Jean-Louis; Drew, David M.; Dünisch, Oliver; Durigan, Giselda; Elifuraha, Elisha; Fedele, Marcio; Ferreira Fedele, Ligia; Figueiredo Filho, Afonso; Finger, César Augusto Guimarães; Franco, Augusto César; Freitas Júnior, João Lima; Galvão, Franklin; Gebrekirstos, Aster; Gliniars, Robert; Lima De Alencastro Graça, Paulo Maurício; Griffiths, Anthony D.; Grogan, James; Guan, Kaiyu; Homeier, Jürgen; Kanieski, Maria Raquel; Kho, Lip Khoon; Koenig, Jennifer; Kohler, Sintia Valerio; Krepkowski, Julia; Lemos-filho, José Pires; Lieberman, Diana; Lieberman, Milton Eugene; Lisi, Claudio Sergio; Longhi Santos, Tomaz; López Ayala, José Luis; Maeda, Eduardo Eijji; Malhi, Yadvinder; Maria, Vivian R.B.; Marques, Marcia C.M.; Marques, Renato; Maza Chamba, Hector; Mbwambo, Lawrence; Melgaço, Karina Liana Lisboa; Mendivelso, Hooz Angela; Murphy, Brett P.; O'Brien, Joseph J.; Oberbauer, Steven F.; Okada, Naoki; Pélissier, Raphaël; Prior, Lynda D.; Roig, Fidel Alejandro; Ross, Michael; Rossatto, Davi Rodrigo; Rossi, Vivien; Rowland, Lucy; Rutishauser, Ervan; Santana, Hellen; Schulze, Mark; Selhorst, Diogo; Silva, Williamar Rodrigues; Silveira, Marcos; Spannl, Susanne; Swaine, Michael D.; Toledo, José Julio; Toledo, Marcos Miranda; Toledo, Marisol; Toma, Takeshi; Tomazello Filho, Mario; Valdez Hernández, Juan Ignacio; Verbesselt, Jan; Vieira, Simone Aparecida; Vincent, Grégoire; Volkmer De Castilho, Carolina; Volland, Franziska; Worbes, Martin; Zanon, Magda Lea Bolzan; Aragão, Luiz E.O.C.

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 incl

  19. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    NARCIS (Netherlands)

    Wagner, Fabien H.; Hérault, Bruno; Bonal, Damien; Stahl, Clément; Anderson, Liana O.; Baker, Timothy R.; Becker, Gabriel Sebastian; Beeckman, Hans; Boanerges Souza, Danilo; Botosso, Paulo Cesar; Bowman, David M.J.S.; Bräuning, Achim; Brede, Benjamin; Brown, Foster Irving; Camarero, Jesus Julio; Camargo, Plínio Barbosa; Cardoso, Fernanda C.G.; Carvalho, Fabrício Alvim; Castro, Wendeson; Chagas, Rubens Koloski; Chave, Jérome; Chidumayo, Emmanuel N.; Clark, Deborah A.; Costa, Flavia Regina Capellotto; Couralet, Camille; Silva Mauricio, Da Paulo Henrique; Dalitz, Helmut; Castro, De Vinicius Resende; Freitas Milani, De Jaçanan Eloisa; Oliveira, De Edilson Consuelo; Souza Arruda, De Luciano; Devineau, Jean-Louis; Drew, David M.; Dünisch, Oliver; Durigan, Giselda; Elifuraha, Elisha; Fedele, Marcio; Ferreira Fedele, Ligia; Figueiredo Filho, Afonso; Finger, César Augusto Guimarães; Franco, Augusto César; Freitas Júnior, João Lima; Galvão, Franklin; Gebrekirstos, Aster; Gliniars, Robert; Lima De Alencastro Graça, Paulo Maurício; Griffiths, Anthony D.; Grogan, James; Guan, Kaiyu; Homeier, Jürgen; Kanieski, Maria Raquel; Kho, Lip Khoon; Koenig, Jennifer; Kohler, Sintia Valerio; Krepkowski, Julia; Lemos-filho, José Pires; Lieberman, Diana; Lieberman, Milton Eugene; Lisi, Claudio Sergio; Longhi Santos, Tomaz; López Ayala, José Luis; Maeda, Eduardo Eijji; Malhi, Yadvinder; Maria, Vivian R.B.; Marques, Marcia C.M.; Marques, Renato; Maza Chamba, Hector; Mbwambo, Lawrence; Melgaço, Karina Liana Lisboa; Mendivelso, Hooz Angela; Murphy, Brett P.; O'Brien, Joseph J.; Oberbauer, Steven F.; Okada, Naoki; Pélissier, Raphaël; Prior, Lynda D.; Roig, Fidel Alejandro; Ross, Michael; Rossatto, Davi Rodrigo; Rossi, Vivien; Rowland, Lucy; Rutishauser, Ervan; Santana, Hellen; Schulze, Mark; Selhorst, Diogo; Silva, Williamar Rodrigues; Silveira, Marcos; Spannl, Susanne; Swaine, Michael D.; Toledo, José Julio; Toledo, Marcos Miranda; Toledo, Marisol; Toma, Takeshi; Tomazello Filho, Mario; Valdez Hernández, Juan Ignacio; Verbesselt, Jan; Vieira, Simone Aparecida; Vincent, Grégoire; Volkmer De Castilho, Carolina; Volland, Franziska; Worbes, Martin; Zanon, Magda Lea Bolzan; Aragão, Luiz E.O.C.

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68

  20. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    NARCIS (Netherlands)

    Wagner, Fabien H.; Hérault, Bruno; Bonal, Damien; Stahl, Clément; Anderson, Liana O.; Baker, Timothy R.; Becker, Gabriel Sebastian; Beeckman, Hans; Boanerges Souza, Danilo; Botosso, Paulo Cesar; Bowman, David M.J.S.; Bräuning, Achim; Brede, Benjamin; Brown, Foster Irving; Camarero, Jesus Julio; Camargo, Plínio Barbosa; Cardoso, Fernanda C.G.; Carvalho, Fabrício Alvim; Castro, Wendeson; Chagas, Rubens Koloski; Chave, Jérome; Chidumayo, Emmanuel N.; Clark, Deborah A.; Costa, Flavia Regina Capellotto; Couralet, Camille; Silva Mauricio, Da Paulo Henrique; Dalitz, Helmut; Castro, De Vinicius Resende; Freitas Milani, De Jaçanan Eloisa; Oliveira, De Edilson Consuelo; Souza Arruda, De Luciano; Devineau, Jean-Louis; Drew, David M.; Dünisch, Oliver; Durigan, Giselda; Elifuraha, Elisha; Fedele, Marcio; Ferreira Fedele, Ligia; Figueiredo Filho, Afonso; Finger, César Augusto Guimarães; Franco, Augusto César; Freitas Júnior, João Lima; Galvão, Franklin; Gebrekirstos, Aster; Gliniars, Robert; Lima De Alencastro Graça, Paulo Maurício; Griffiths, Anthony D.; Grogan, James; Guan, Kaiyu; Homeier, Jürgen; Kanieski, Maria Raquel; Kho, Lip Khoon; Koenig, Jennifer; Kohler, Sintia Valerio; Krepkowski, Julia; Lemos-filho, José Pires; Lieberman, Diana; Lieberman, Milton Eugene; Lisi, Claudio Sergio; Longhi Santos, Tomaz; López Ayala, José Luis; Maeda, Eduardo Eijji; Malhi, Yadvinder; Maria, Vivian R.B.; Marques, Marcia C.M.; Marques, Renato; Maza Chamba, Hector; Mbwambo, Lawrence; Melgaço, Karina Liana Lisboa; Mendivelso, Hooz Angela; Murphy, Brett P.; O'Brien, Joseph J.; Oberbauer, Steven F.; Okada, Naoki; Pélissier, Raphaël; Prior, Lynda D.; Roig, Fidel Alejandro; Ross, Michael; Rossatto, Davi Rodrigo; Rossi, Vivien; Rowland, Lucy; Rutishauser, Ervan; Santana, Hellen; Schulze, Mark; Selhorst, Diogo; Silva, Williamar Rodrigues; Silveira, Marcos; Spannl, Susanne; Swaine, Michael D.; Toledo, José Julio; Toledo, Marcos Miranda; Toledo, Marisol; Toma, Takeshi; Tomazello Filho, Mario; Valdez Hernández, Juan Ignacio; Verbesselt, Jan; Vieira, Simone Aparecida; Vincent, Grégoire; Volkmer De Castilho, Carolina; Volland, Franziska; Worbes, Martin; Zanon, Magda Lea Bolzan; Aragão, Luiz E.O.C.

    2016-01-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 incl

  1. Estimating leakage from forest carbon sequestration programs

    Energy Technology Data Exchange (ETDEWEB)

    Murray, B.C. [RTI International, Research Triangle Park, NC (United States); McCarl, B.A. [Texas A and M Univ., College Station, TX (United States). Dept. of Agricultural Economics; Lee, H.C. [Western Ontario Univ., London, ON (Canada). Dept. of Economics

    2003-03-01

    Nearly half of all terrestrial carbon is stored in forest ecosystems. Land use changes such as deforestation were responsible for nearly 20 per cent of carbon dioxide (CO{sub 2}) released in the atmosphere worldwide between 1989 to 1998. This paper developed an estimation procedure that addressed the magnitude of potential leakage from carbon sequestration projects in the forest sector, including the conversion of land from agriculture to forest. Leakage occurs when a program's direct carbon benefits are undermined by carbon releases elsewhere. Leakage directly undermines greenhouse gas (GHG) emission reducing actions and should be considered when designing and evaluating policies. Leakage should be deducted from the carbon credits granted to mitigation projects, and accounting rules and guidelines for crediting carbon sequestration projects. Analytic, econometric, and sector-level optimization models were combined to estimate leakage from different forest carbon sequestration activities. The FASOM forest and agricultural sector model was used to investigate empirical leakage consequences in 4 categories: forest setasides, avoided deforestation, afforestation, and a combination of afforestation and avoided deforestation. The interaction of market forces that cause leakage from forest sector projects was investigated. Results suggested that leakage from geographically targeted mitigation projects can be sizeable. For small projects, leakage tends to be larger in proportion to direct project benefits than larger programs or policies. It was suggested that if leakage is more pronounced in forest carbon projects than energy sector projects, this could affect the terms of trade for the credits generated by different sources and thereby affect the optimal portfolio of mitigation options. It was concluded that policy designers and market makers should account for leakage effects when enabling exchanges of GHG offsets.

  2. The role of forest disturbance in global forest mortality and terrestrial carbon fluxes

    Science.gov (United States)

    Pugh, Thomas; Arneth, Almut; Smith, Benjamin; Poulter, Benjamin

    2017-04-01

    stocks is very large, illustrating the importance of further efforts to distinguish disturbance drivers at the global scale. Setting our knowledge of forest disturbance into the wider uncertainty in forest mortality processes generally, we offer a perspective for improving understanding of the role of disturbance in global forest carbon cycling.

  3. Forest carbon sinks in the Northern Hemisphere

    Science.gov (United States)

    Christine L. Goodale; Michael J. Apps; Richard A. Birdsey; Christopher B. Field; Linda S. Heath; Richard A. Houghton; Jennifer C. Jenkins; Gundolf H. Kohlmaier; Werner Kurz; Shirong Liu; Gert-Jan Nabuurs; Sten Nilsson; Anatoly Z. Shvidenko

    2002-01-01

    There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary greatly. National forest inventories provide strong, measurement-based constraints on the magnitude of net forest carbon uptake. We brought together...

  4. Carbon Stock and Carbon Cycle of Wetland Ecosystem

    Institute of Scientific and Technical Information of China (English)

    Zhangquan; ZENG; Canming; ZHANG; Jiao; LI; Nan; YANG; Xihao; LI; Yandong; NIU; Zijian; WU

    2014-01-01

    Wetland ecosystem is an essential ecosystem in the world. Its organic carbon stock and carbon cycle are important basis of global carbon cycle researches and also major contents of global climate change researches. Researches have shown that wetland protection and restoration can promote carbon accumulation and reduce emission of greenhouse gases. This paper discussed influence of carbon stock and carbon balance of wetland ecosystem and emission of greenhouse gases,as well as the relationship between wetland and global climate changes. Finally,it made prospect on researches about carbon cycle of Dongting Lake.

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

    Directory of Open Access Journals (Sweden)

    Peckham Scott D

    2012-06-01

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

  6. Material Flows and Carbon Cycles

    Science.gov (United States)

    Worrell, E.

    2003-12-01

    The industrial sector emits almost 43 percent of the global anthropogenic carbon dioxide emissions to produce materials and products. Furthermore, energy is used to move materials and products and process the waste. Hence, a large amount of energy is consumed and CO2 is emitted to sustain our materials system. Until recently, studies investigating mitigation options focused on changes in the energy system. For industrial processes most studies evaluate how the current materials system can be maintained producing fewer greenhouse gas emissions. Three elements of a strategy to improve the long-term materials productivity are the reduction of dissipative uses of non-biodegradable materials, secondly, the re-design of products to use less material or design for re-use or recycling, and thirdly, develop more efficient technologies for material conversion and recycling. This will reduce or eliminate the need to extract virgin materials from the environment, and reduce CO2 emissions from the energy-intensive production processes. To assess measures to reduce materials consumption, fossil fuels consumption and CO2 emissions, detailed understanding of the material system is needed. The lifecycle of materials has to be investigated including all branches of industry with all the inputs and outputs. We start with a discussion of materials and the carbon cycle focusing on the contribution of materials to anthropogenic carbon flows. We discuss CO2 emissions from energy use in materials extraction and production, fossil (e.g. plastics) and biomass carbon (e.g. lumber, paper) used as feedstock of materials, and mineral sources (e.g. cement). We discuss opportunities to reduce CO2 emissions by improving the efficiency with which society uses materials through product design, material substitution, product reuse and material recycling.

  7. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J.; Turton, Stephen M.; Pert, Petina L.; Edwards, Will; Laurance, William F.

    2016-01-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity. PMID:27435389

  8. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J.; Turton, Stephen M.; Pert, Petina L.; Edwards, Will; Laurance, William F.

    2016-07-01

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m2 of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

  9. Degraded tropical rain forests possess valuable carbon storage opportunities in a complex, forested landscape.

    Science.gov (United States)

    Alamgir, Mohammed; Campbell, Mason J; Turton, Stephen M; Pert, Petina L; Edwards, Will; Laurance, William F

    2016-07-20

    Tropical forests are major contributors to the terrestrial global carbon pool, but this pool is being reduced via deforestation and forest degradation. Relatively few studies have assessed carbon storage in degraded tropical forests. We sampled 37,000 m(2) of intact rainforest, degraded rainforest and sclerophyll forest across the greater Wet Tropics bioregion of northeast Australia. We compared aboveground biomass and carbon storage of the three forest types, and the effects of forest structural attributes and environmental factors that influence carbon storage. Some degraded forests were found to store much less aboveground carbon than intact rainforests, whereas others sites had similar carbon storage to primary forest. Sclerophyll forests had lower carbon storage, comparable to the most heavily degraded rainforests. Our findings indicate that under certain situations, degraded forest may store as much carbon as intact rainforests. Strategic rehabilitation of degraded forests could enhance regional carbon storage and have positive benefits for tropical biodiversity.

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

    Science.gov (United States)

    Dar, Javid Ahmad; Sundarapandian, Somaiah

    2015-02-01

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

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

    Science.gov (United States)

    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

  12. Development and use of long-term, global data records of forest, water, and urban change for terrestrial ecology and carbon cycle science

    Science.gov (United States)

    Sexton, J. O.

    2015-12-01

    Earth's human population has risen over the last century from less than 2 billion to over 7 billion people. The current "Anthropocene Era" has brought changes in Earth's landforms, climate, biodiversity, atmosphere, and hydrologic and biogeochemical cycles, as well as the expansion and intensification of human land use. As the emerging nexus of the physical, biological, and social sciences, measurements of Earth's natural and anthropogenic land cover are needed to understand and manage the coupled dynamics of human and natural systems. In recent years, NASA-sponsored efforts have produced global, time-serial estimates of tree cover using the MOderate-resolution Imaging Spectroradiometer (MODIS) and the world's first global, Landsat-based datasets representing tree and forest cover change from 1990 to 2010. These data are fueling global and national estimates of the rate and acceleration of deforestation as well as international commitments to conserve forest ecosystems. Likewise, Landsat-based datasets documenting Earth's inland surface waters are enabling the world's first global, high-resolution estimates of water cover based on repeatable satellite measurements. Meanwhile, long-term, time-serial estimates of impervious surface cover are being used to model the effect of urbanization on storm-water runoff, watershed health, and stream biodiversity. MODIS-based records of plant phenology are depicting the vulnerability and resilience of ecosystems to drought and are informing land managers of the sensitivity of wildlife to climate and plant phenology. Natural ecosystems are complex and potentially chaotic even in the absence of anthropogenic influence, and so understanding these interactions between physical, biological, and social systems is increasingly crucial under escalating human impacts. Globally consistent, locally accurate, and publicly available records spanning multiple decades at high frequency are the living legacy of the NASA Earth Science Programs

  13. 'Carbon debt’ – lost in the forest?

    DEFF Research Database (Denmark)

    Bentsen, Niclas Scott; Graudal, Lars; Madsen, Palle;

    2014-01-01

    the time lapse between harvest and regrowth may be a signifi cant factor for themodeled carbon debt. A meta-analysis of more than 250 model scenarios was conducted to evaluate the factors and assumptionsdetermining carbon debts and payback time of forest bioenergy supply chains. Factors such as spatial......The concept of ‘carbon debt’ and carbon payback time with reference to bioenergy and biofuels was probably launched by anarticle in Science in 2008. The concept is increasingly seen as an indicator of the sustainability of bioenergy supply chains.Particularly for forest bioenergy supply chains...... and temporal scale, biome,origin of the wood resource, which fossil fuels are displaced, forest history, baseline scenario, accounting principle, and databackground were included in the analysis. This paper discusses the evolution of the carbon debt concept, how different factorsand assumptions infl uence...

  14. 'Carbon debt’ – lost in the forest?

    DEFF Research Database (Denmark)

    Bentsen, Niclas Scott; Graudal, Lars; Madsen, Palle

    2014-01-01

    The concept of ‘carbon debt’ and carbon payback time with reference to bioenergy and biofuels was probably launched by anarticle in Science in 2008. The concept is increasingly seen as an indicator of the sustainability of bioenergy supply chains.Particularly for forest bioenergy supply chains...... the time lapse between harvest and regrowth may be a signifi cant factor for themodeled carbon debt. A meta-analysis of more than 250 model scenarios was conducted to evaluate the factors and assumptionsdetermining carbon debts and payback time of forest bioenergy supply chains. Factors such as spatial...... and temporal scale, biome,origin of the wood resource, which fossil fuels are displaced, forest history, baseline scenario, accounting principle, and databackground were included in the analysis. This paper discusses the evolution of the carbon debt concept, how different factorsand assumptions infl uence...

  15. Defaunation affects carbon storage in tropical forests.

    Science.gov (United States)

    Bello, Carolina; Galetti, Mauro; Pizo, Marco A; Magnago, Luiz Fernando S; Rocha, Mariana F; Lima, Renato A F; Peres, Carlos A; Ovaskainen, Otso; Jordano, Pedro

    2015-12-01

    Carbon storage is widely acknowledged as one of the most valuable forest ecosystem services. Deforestation, logging, fragmentation, fire, and climate change have significant effects on tropical carbon stocks; however, an elusive and yet undetected decrease in carbon storage may be due to defaunation of large seed dispersers. Many large tropical trees with sizeable contributions to carbon stock rely on large vertebrates for seed dispersal and regeneration, however many of these frugivores are threatened by hunting, illegal trade, and habitat loss. We used a large data set on tree species composition and abundance, seed, fruit, and carbon-related traits, and plant-animal interactions to estimate the loss of carbon storage capacity of tropical forests in defaunated scenarios. By simulating the local extinction of trees that depend on large frugivores in 31 Atlantic Forest communities, we found that defaunation has the potential to significantly erode carbon storage even when only a small proportion of large-seeded trees are extirpated. Although intergovernmental policies to reduce carbon emissions and reforestation programs have been mostly focused on deforestation, our results demonstrate that defaunation, and the loss of key ecological interactions, also poses a serious risk for the maintenance of tropical forest carbon storage.

  16. Linking brownification to carbon cycling in headwater streams

    Science.gov (United States)

    Fasching, C.; Behounek, B.; Singer, G. A.; Battin, T. J.

    2013-12-01

    Brownification of inland waters is becoming a global phenomenon with major implications for aquatic ecology and drinking water supply. The unprecedented export of humic substances from the terrestrial environment causes this notable change in colour of stream and lake waters. Given the net heterotrophy of most inland waters, altered carbon fluxes may impact microbial metabolism and ultimately carbon dioxide emissions from these inland waters. Yet the implications for carbon cycling remain elusive. Here, we investigate the coupling of microbial metabolism, organic carbon characteristics and streamwater CO2 concntration along a brownification gradient in 20 headwater streams draining catchments covered with coniferous forest and peatland in the Bohemian Massive, Austria. We break down brownification into its components of concentration and quality, and relate each to carbon cycling in headwater streams. Brownification did not only increase streamwater dissolved organic matter (DOM) concentration but also induced changes in DOM quality. Humic-like and aromatic compounds of terrigenous origin -- conferring the brown colour to the water -- were metabolised by microbial heterotrophs in the streamwater yet at the cost of low carbon use efficiency (CUE). Potential CO2 evasion from headwaters was controlled by the quantity of bioavailable carbon as well as by the coupling of carbon qulity and microbial metabolism. This implies brownification to contribute to CO2 evasion from streams as a large fraction of terrigenous organic carbon is respired by microbial heterotrophs along the flow path. Our results illuminate the impact of brownification on carbon cycling which may gain relevance as global change progresses.

  17. Ecological Meaning and Consideration of Economic Forest Carbon Sinks in China----Take Yan-Shan Chestnut for Example

    Science.gov (United States)

    Wang, Z.; Li, H.; Zhang, W. W.; Liu, S. R.

    Along with our country scientific researchers' study on native forest carbon sinks as well as the summary of the increasing amount of China's forest carbon, With the deepening of our scientists on the study of the national forest carbon sinks, forest carbon sinks has become a favorable support for climate diplomacy. Currently, a lot of work has focused on the carbon cycle, the level of carbon sinks of forest ecosystems, but the characteristics of economic forest carbon sinks are in a blank state. Beijing chestnut is one of the national food strategic security stockpiles, and estimate the potential of economic forest carbon sinks has important scientific significance to the establishment of carbon sink function area, and expansion of sustainable economic and social development of response measures.

  18. Environmental change and the carbon balance of Amazonian forests.

    Science.gov (United States)

    Aragão, Luiz E O C; Poulter, Benjamin; Barlow, Jos B; Anderson, Liana O; Malhi, Yadvinder; Saatchi, Sassan; Phillips, Oliver L; Gloor, Emanuel

    2014-11-01

    Extreme climatic events and land-use change are known to influence strongly the current carbon cycle of Amazonia, and have the potential to cause significant global climate impacts. This review intends to evaluate the effects of both climate and anthropogenic perturbations on the carbon balance of the Brazilian Amazon and to understand how they interact with each other. By analysing the outputs of the Intergovernmental Panel for Climate Change (IPCC) Assessment Report 4 (AR4) model ensemble, we demonstrate that Amazonian temperatures and water stress are both likely to increase over the 21st Century. Curbing deforestation in the Brazilian Amazon by 62% in 2010 relative to the 1990s mean decreased the Brazilian Amazon's deforestation contribution to global land use carbon emissions from 17% in the 1990s and early 2000s to 9% by 2010. Carbon sources in Amazonia are likely to be dominated by climatic impacts allied with forest fires (48.3% relative contribution) during extreme droughts. The current net carbon sink (net biome productivity, NBP) of +0.16 (ranging from +0.11 to +0.21) Pg C year(-1) in the Brazilian Amazon, equivalent to 13.3% of global carbon emissions from land-use change for 2008, can be negated or reversed during drought years [NBP = -0.06 (-0.31 to +0.01) Pg C year(-1) ]. Therefore, reducing forest fires, in addition to reducing deforestation, would be an important measure for minimizing future emissions. Conversely, doubling the current area of secondary forests and avoiding additional removal of primary forests would help the Amazonian gross forest sink to offset approximately 42% of global land-use change emissions. We conclude that a few strategic environmental policy measures are likely to strengthen the Amazonian net carbon sink with global implications. Moreover, these actions could increase the resilience of the net carbon sink to future increases in drought frequency. © 2014 The Authors. Biological Reviews © 2014 Cambridge Philosophical

  19. Impacts of harvesting forest residues for bioenergy on nutrient cycling and community assemblages in northern hardwood forests

    Energy Technology Data Exchange (ETDEWEB)

    Donner, D.M.; Zalesny, R.S. [United States Dept. of Agriculture Forest Service, Rhinelander, WI (United States). Northern Research Station, Inst. for Applied Ecosystem Studies; St Pierre, M.; Eklund, D. [Chequamegon-Nicolet National Forest, Rhinelander, WI (United States); Coyle, D.R. [Wisconsin Univ., Madison, WI (United States). Dept. of Entomology; Ribic, C.A. [Wisconsin Univ., Madison, WI (United States). United States Geological Survey, WI Cooperative Wildlife Research Unit

    2010-07-01

    This study assessed the impacts of whole-tree harvesting on the nutrient cycles and community assemblages in northern hardwood forests. The woody biomass left on the forest floor after logging is important for nutrient cycling in addition to providing seed beds and creating habitats for wildlife. The impact of fine woody debris (FWD) removal on nutrient availability and above and below ground community assemblages on rich soils in regenerating northern hardwood stands in Wisconsin was investigated at 9 sites within a national forest. Soil carbon and nitrogen availability was assessed. Insect pitfalls, amphibian time-constraint searches, herbaceous plant quadrants, and soil cores along transects were sampled during the summer months of 2009. Results of the study will be used to evaluate the trade-offs of harvesting woody biomass on public lands for energy use as well as to develop management guidelines for maintaining biodiversity and forest health.

  20. Policy Considerations for Using Forests to Mitigate Carbon Dioxide Emissions

    Directory of Open Access Journals (Sweden)

    Sandra Brown

    2001-01-01

    Full Text Available A recent article in Nature, “Soil Fertility Limits Carbon Sequestration by Forest Ecosystems in a CO2-Enriched Atmosphere” by Oren and colleagues[1], has been widely reported on, and often misinterpreted, by the press. The article dampens enthusiasm for accelerated forest growth due to CO2 fertilization and puts in question the fringe theory that the world’s forests can provide an automatic mitigation feedback. We agree that these results increase our understanding of the global carbon cycle. At the same time, their relevance in the context of the international climate change negotiations is much more complicated than portrayed by newspapers such as the New York Times (“Role of Trees in Curbing Greenhouse Gases is Challenged”, May 24, 2001 and the Christian Science Monitor (“Trees No Savior for Global Warming”, May 25, 2001.

  1. Upscaling diurnal cycles of carbon fluxes

    Science.gov (United States)

    Bodesheim, Paul; Jung, Martin; Mahecha, Miguel; Reichstein, Markus

    2017-04-01

    Carbon fluxes like Gross Primary Production (GPP) and Net Ecosystem Exchange (NEE) are important variables for studying interactions between the atmosphere and the biosphere in different ecosystems. They are typically derived from measurements at Eddy covariance towers and the FLUXNET global network consists of hundreds of such sites. In order to diagnose global GPP and NEE patterns from FLUXNET, upscaling approaches have been used in the past to extrapolate the site measurements to continental and global scale. However, respective products have a daily or monthly temporal resolution and do not allow for analyzing patterns related to diurnal variations of GPP and NEE. To raise these upscaling approaches to the next level, we present our first results on upscaling diurnal cycles of GPP and NEE with half-hourly resolution. We use random forest regression models to estimate the relationship between predictor variables and fluxes based on more than four million half-hourly observations from FLUXNET sites. We have developed and tested two approaches that overcome the mismatch in the temporal resolution between predictor variables at daily resolution and fluxes at half-hourly resolution. Based on thorough leave-one-site-out cross-validation we show that the approach works very well. Finally, we used the trained models for computing global products of half-hourly GPP and NEE that cover the years 2001 to 2014 and present global patterns of diurnal carbon flux variations derived from the upscaling approach.

  2. Tropical forest soil microbial communities couple iron and carbon biogeochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Dubinsky, E.A.; Silver, W.L.; Firestone, M.K.

    2009-10-15

    We report that iron-reducing bacteria are primary mediators of anaerobic carbon oxidation in upland tropical soils spanning a rainfall gradient (3500 - 5000 mm yr-1) in northeast Puerto Rico. The abundant rainfall and high net primary productivity of these tropical forests provide optimal soil habitat for iron-reducing and iron-oxidizing bacteria. Spatially and temporally dynamic redox conditions make iron-transforming microbial communities central to the belowground carbon cycle in these wet tropical forests. The exceedingly high abundance of iron-reducing bacteria (up to 1.2 x 10{sup 9} cells per gram soil) indicated that they possess extensive metabolic capacity to catalyze the reduction of iron minerals. In soils from the higher rainfall sites, measured rates of ferric iron reduction could account for up to 44 % of organic carbon oxidation. Iron reducers appeared to compete with methanogens when labile carbon availability was limited. We found large numbers of bacteria that oxidize reduced iron at sites with high rates of iron reduction and large numbers of iron-reducers. the coexistence of large populations of ironreducing and iron-oxidizing bacteria is evidence for rapid iron cycling between its reduced and oxidized states, and suggests that mutualistic interactions among these bacteria ultimately fuel organic carbon oxidation and inhibit CH4 production in these upland tropical forests.

  3. Organic carbon inventories in natural and restored Ecuadorian mangrove forests.

    Science.gov (United States)

    DelVecchia, Amanda G; Bruno, John F; Benninger, Larry; Alperin, Marc; Banerjee, Ovik; de Dios Morales, Juan

    2014-01-01

    Mangroves can capture and store organic carbon and their protection and therefore their restoration is a component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hampered the inclusion of sequestration by mangroves in carbon cycle models and in carbon offset markets. The purpose of this study was to estimate the relative carbon capture and storage potential in natural and restored mangrove forests. We measured depth profiles of soil organic carbon content in 72 cores collected from six sites (three natural, two restored, and one afforested) surrounding Muisne, Ecuador. Samples up to 1 m deep were analyzed for organic matter content using loss-on-ignition and values were converted to organic carbon content using an accepted ratio of 1.72 (g/g). Results suggest that average soil carbon storage is 0.055 ± 0.002 g cm(-3) (11.3 ± 0.8% carbon content by dry mass, mean ± 1 SE) up to 1 m deep in natural sites, and 0.058 ± 0.002 g cm(-3) (8.0 ± 0.3%) in restored sites. These estimates are concordant with published global averages. Evidence of equivalent carbon stocks in restored and afforested mangrove patches emphasizes the carbon sink potential for reestablished mangrove systems. We found no relationship between sediment carbon storage and aboveground biomass, forest structure, or within-patch location. Our results demonstrate the long-term carbon storage potential of natural mangroves, high effectiveness of mangrove restoration and afforestation, a lack of predictability in carbon storage strictly based on aboveground parameters, and the need to establish standardized protocol for quantifying mangrove sediment carbon stocks.

  4. Authigenic Carbonate and the History of the Global Carbon Cycle

    Science.gov (United States)

    Schrag, Daniel P.; Higgins, John. A.; Macdonald, Francis A.; Johnston, David T.

    2013-02-01

    We present a framework for interpreting the carbon isotopic composition of sedimentary rocks, which in turn requires a fundamental reinterpretation of the carbon cycle and redox budgets over Earth's history. We propose that authigenic carbonate, produced in sediment pore fluids during early diagenesis, has played a major role in the carbon cycle in the past. This sink constitutes a minor component of the carbon isotope mass balance under the modern, high levels of atmospheric oxygen but was much larger in times of low atmospheric O2 or widespread marine anoxia. Waxing and waning of a global authigenic carbonate sink helps to explain extreme carbon isotope variations in the Proterozoic, Paleozoic, and Triassic.

  5. Carbon sequestration, optimum forest rotation and their environmental impact

    Energy Technology Data Exchange (ETDEWEB)

    Kula, Erhun, E-mail: erhun.kula@bahcesehir.edu.tr [Department of Economics, Bahcesehir University, Besiktas, Istanbul (Turkey); Gunalay, Yavuz, E-mail: yavuz.gunalay@bahcesehir.edu.tr [Department of Business Studies, Bahcesehir University, Besiktas, Istanbul (Turkey)

    2012-11-15

    Due to their large biomass forests assume an important role in the global carbon cycle by moderating the greenhouse effect of atmospheric pollution. The Kyoto Protocol recognises this contribution by allocating carbon credits to countries which are able to create new forest areas. Sequestrated carbon provides an environmental benefit thus must be taken into account in cost-benefit analysis of afforestation projects. Furthermore, like timber output carbon credits are now tradable assets in the carbon exchange. By using British data, this paper looks at the issue of identifying optimum felling age by considering carbon sequestration benefits simultaneously with timber yields. The results of this analysis show that the inclusion of carbon benefits prolongs the optimum cutting age by requiring trees to stand longer in order to soak up more CO{sub 2}. Consequently this finding must be considered in any carbon accounting calculations. - Highlights: Black-Right-Pointing-Pointer Carbon sequestration in forestry is an environmental benefit. Black-Right-Pointing-Pointer It moderates the problem of global warming. Black-Right-Pointing-Pointer It prolongs the gestation period in harvesting. Black-Right-Pointing-Pointer This paper uses British data in less favoured districts for growing Sitka spruce species.

  6. Rapid Accumulation and Turnover of Soil Carbon in a Re-Establishing Forest

    Science.gov (United States)

    Daniel D. Richter; Daniel Markewitz; Susan E. Trumbore; Carol G. Wells

    1999-01-01

    Present understanding of the global carbon cycle is limited by uncertainty over soil-carbon dynamics. The clearing of the world's forests, mainly for agricultural uses, releases large amounts of carbon to the atmosphere (up to 2 X 1015yr-1), much of which arises firon the cultivation driving an accelerated...

  7. Comparison of the carbon stock in forest soil of sessile oak and beech forests

    Science.gov (United States)

    Horváth, Adrienn; Bene, Zsolt; Bidló, András

    2016-04-01

    Forest ecosystems are the most important carbon sinks. The forest soils play an important role in the global carbon cycle, because the global climate change or the increase of atmospheric CO2 level. We do not have enough data about the carbon stock of soils and its change due to human activities, which have similar value to carbon content of biomass. In our investigation we measured the carbon stock of soil in 10 stands of Quercus petraea and Fagus sylvatica. We took a 1.1 m soil column with soil borer and divided to 11 samples each column. The course organic and root residues were moved. After evaluation, we compared our results with other studies and the carbon stock of forests to each other. Naturally, the amount of SOC was the highest in the topsoil layers. However, we found significant difference between forest stands which stayed on the same homogenous bedrock, but very close to each other (e.g. distance was 1 or 2 km). We detected that different forest utilizations and tree species have an effect on the forest carbon as the litter as well (amount, composition). In summary, we found larger amount (99.1 C t/ha on average) of SOC in soil of stands, where sessile oak were the main stand-forming tree species. The amount of carbon was the least in turkey oak-sessile oak stands (85.4 C t/ha on average). We found the highest SOC (118.3 C t/ha) in the most mixed stand (silver lime-beech-red oak). In the future, it will be very important: How does climate change affect the spread of tree species or on carbon storage? Beech is more sensitive, but even sessile oak. These species are expected to replace with turkey oak, which is less sensitive to drought. Thus, it is possible in the future that we can expect to decrease of forest soil carbon stock capacity, which was confirmed by our experiment. Keywords: carbon sequestration, mitigation, Fagus sylvatica, Quercus petraea, litter Acknowledgements: Research is supported by the "Agroclimate.2" (VKSZ_12-1-2013-0034) EU

  8. Effects of Deforestation and Forest Degradation on Forest Carbon Stocks in Collaborative Forests, Nepal

    Directory of Open Access Journals (Sweden)

    Ram Asheshwar MANDAL

    2012-12-01

    Full Text Available There are some key drivers that favor deforestation and forest degradation. Consequently, levels of carbon stock are affected in different parts of same forest types. But the problem lies in exploring the extent of the effects on level of carbon stocking. This paper highlights the variations in levels of carbon stocks in three different collaborative forests of same forest type i.e. tropical sal (Shorea robusta forest in Mahottari district of the central Terai in Nepal. Three collaborative forests namely Gadhanta-Bardibas Collaborative Forest (CFM, Tuteshwarnath CFM and Banke- Maraha CFM were selected for research site. Interview and workshops were organized with the key informants that include staffs, members and representatives of CFMs to collect the socio-economic data and stratified random sampling was applied to collect the bio-physical data to calculate the carbon stocks. Analysis was carried out using statistical tools. It was found five major drivers namely grazing, fire, logging, growth of invasive species and encroachment. It was found highest carbon 269.36 ton per ha in Gadhanta- Bardibash CFM. The findings showed that the levels of carbon stocks in the three studied CFMs are different depending on how the drivers of deforestation and forest degradation influence over them.

  9. The fundamentals. The carbon cycle; Les fondamentaux. Le cycle du carbone

    Energy Technology Data Exchange (ETDEWEB)

    Jupin, H. [Universite de Perpignan, 66 (France)

    1996-12-31

    This book considers the main characteristics of the carbon cycle. After speaking about the fundamental notions of the matter cycles and flow, the carbon cycle processes (photosynthesis and respiration) are briefly tackled. The analysis of the carbon cycle in the terrestrial and aquatic environment allows to show up the interactions with the water, the sulfur and the nitrogen cycles. In the last part the author takes stock on many controversial questions: interactions between the carbon cycle and the climatic change, consequences of the human utilization of fossil fuels. (A.L.B.) 7 refs.

  10. Restoring forest structure and process stabilizes forest carbon in wildfire-prone southwestern ponderosa pine forests.

    Science.gov (United States)

    Hurteau, Matthew D; Liang, Shuang; Martin, Katherine L; North, Malcolm P; Koch, George W; Hungate, Bruce A

    2016-03-01

    Changing climate and a legacy of fire-exclusion have increased the probability of high-severity wildfire, leading to an increased risk of forest carbon loss in ponderosa pine forests in the southwestern USA. Efforts to reduce high-severity fire risk through forest thinning and prescribed burning require both the removal and emission of carbon from these forests, and any potential carbon benefits from treatment may depend on the occurrence of wildfire. We sought to determine how forest treatments alter the effects of stochastic wildfire events on the forest carbon balance. We modeled three treatments (control, thin-only, and thin and burn) with and without the occurrence of wildfire. We evaluated how two different probabilities of wildfire occurrence, 1% and 2% per year, might alter the carbon balance of treatments. In the absence of wildfire, we found that thinning and burning treatments initially reduced total ecosystem carbon (TEC) and increased net ecosystem carbon balance (NECB). In the presence of wildfire, the thin and burn treatment TEC surpassed that of the control in year 40 at 2%/yr wildfire probability, and in year 51 at 1%/yr wildfire probability. NECB in the presence of wildfire showed a similar response to the no-wildfire scenarios: both thin-only and thin and burn treatments increased the C sink. Treatments increased TEC by reducing both mean wildfire severity and its variability. While the carbon balance of treatments may differ in more productive forest types, the carbon balance benefits from restoring forest structure and fire in southwestern ponderosa pine forests are clear.

  11. Spatio-temporal patterns of forest carbon dioxide exchange based on global eddy covariance measurements

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Spatio-temporal patterns and driving mechanisms of forest carbon dioxide (CO2) exchange are the key issues on terrestrial ecosystem carbon cycles, which are the basis for developing and validating ecosystem carbon cycle models, assessing and predicting the role of forests in global carbon balance. Eddy covariance (EC) technique, an important method for measuring energy and material exchanges between terrestrial ecosystems and the atmosphere, has made a great contribution to understanding CO2 exchanges in the biosphere during the past decade. Here, we synthesized published EC flux measurements at various forest sites in the global network of eddy flux tower sites (FLUXNET) and regional flux networks. Our objective was to explore spatio-temporal patterns and driving factors on forest carbon fluxes, i.e. net ecosystem productivity (NEP), gross primary productivity (GPP) and total ecosystem respiration (TER). Globally, forest NEP exhibited a significant latitudinal pattern jointly controlled by GPP and TER. The NEP decreased in an order of warm temperate forest > cold temperate and tropical rain forests > boreal and subalpine forests. Mean annual temperature (MAT) made a greater contribution to forest carbon fluxes than sum of annual precipitation (SAP). As MAT increased, the GPP increased linearly, whereas the TER increased exponentially, resulting in the NEP decreasing beyond an MAT threshold of 20°C. The GPP, TER and NEP varied substantially when the SAP was less than 1500 mm, but tended to increase with increasing SAP. Temporal dynamics in forest carbon fluxes and determinants depended upon time scales. NEP showed a significant interannual variability mainly driven by climate fluctuations and different responses of the GPP and TER to environmental forcing. In a longer term, forest carbon fluxes had a significant age effect. The ecosystem was a net carbon source right after clearcutting, gradually switched to a net carbon sink when the relative stand age (i

  12. Spatio-temporal patterns of forest carbon dioxide ex change based on global eddy covariance measurements

    Institute of Scientific and Technical Information of China (English)

    WANG XingChang; WANG ChuanKuan; YU GuiRui

    2008-01-01

    Spatio-temporal patterns and driving mechanisms of forest carbon dioxide (CO2) exchange are the key issues on terrestrial ecosystem carbon cycles, which are the basis for developing and validating ecosystem carbon cycle models, assessing and predicting the role of forests in global carbon balance.Eddy covariance (EC) technique, an important method for measuring energy and material exchanges between terrestrial ecosystems and the atmosphere, has made a great contribution to understanding CO2 exchanges in the biosphere during the past decade. Here, we synthesized published EC flux measurements at various forest sites in the global network of eddy flux tower sites (FLUXNET) and regional flux networks. Our objective was to explore spatio-temporal patterns and driving factors on forest carbon fluxes, i.e. net ecosystem productivity (NEP), gross primary productivity (GPP) and total ecosystem respiration (TER). Globally, forest NEP exhibited a significant latitudinal pattern jointly controlled by GPP and TER. The NEP decreased in an order of warm temperate forest > cold temperate and tropical rain forests > boreal and subalpine forests. Mean annual temperature (MAT) made a greater contribution to forest carbon fluxes than sum of annual precipitation (SAP). As MAT increased, the GPP increased linearly, whereas the TER increased exponentially, resulting in the NEP decreasing beyond an MAT threshold of 20℃. The GPP, TER and NEP varied substantially when the SAP was less than 1500 mm, but tended to increase with increasing SAP. Temporal dynamics in forest carbon fluxes and determinants depended upon time scales. NEP showed a significant interannual variability mainly driven by climate fluctuations and different responses of the GPP and TER to environmental forcing. In a longer term, forest carbon fluxes had a significant age effect. The ecosystem was a net carbon source right after clearcutting, gradually switched to a net carbon sink when the relative stand age (i

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

    Science.gov (United States)

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

    2017-08-01

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

  14. Impacts of Invasive Pests on Forest Carbon and Nitrogen Dynamics

    Science.gov (United States)

    Lovett, G. M.; Crowley, K. F.

    2014-12-01

    Forests of the U.S. have been subject to repeated invasions of destructive insects and diseases imported from other continents. Like other disturbances, these pests can produce short-term ecosystem effects due to tree mortality, but unlike other disturbances, they often target individual species and therefore can cause long-term species change in the forest. Because tree species vary in their influence on carbon (C) and nitrogen (N) cycles, pest-induced species change can radically alter the biogeochemistry of a forest. In this paper we use both data and modeling to examine how pest-induced species change may alter the C and N cycling in forests of the eastern U.S. We describe a new forest ecosystem model that distinguishes individual tree species and allows species composition to shift over the course of the model run. Results indicate that the mortality of eastern hemlock (Tsuga canadensis) by hemlock woolly adelgid and its replacement by faster-growing species such as black birch (Betula lenta) will reduce forest floor C stocks but increase productivity as the birch become established. Decline of American beech (Fagus grandifolia) from beech bark disease and its replacement by sugar maple (Acer saccharum) is likely to decrease soil C storage and increase N leaching from the ecosystem. Responses to other invasive pests will also be discussed. The magnitude of these species-specific effects on C and N cycling is in many cases larger than direct effects expected from changes in climate and atmospheric N deposition, indicating that species change should be included in models that predict forest ecosystem function under future environmental conditions.

  15. Carbon cycle in advanced coal chemical engineering.

    Science.gov (United States)

    Yi, Qun; Li, Wenying; Feng, Jie; Xie, Kechang

    2015-08-07

    This review summarizes how the carbon cycle occurs and how to reduce CO2 emissions in highly efficient carbon utilization from the most abundant carbon source, coal. Nowadays, more and more attention has been paid to CO2 emissions and its myriad of sources. Much research has been undertaken on fossil energy and renewable energy and current existing problems, challenges and opportunities in controlling and reducing CO2 emission with technologies of CO2 capture, utilization, and storage. The coal chemical industry is a crucial area in the (CO2 value chain) Carbon Cycle. The realization of clean and effective conversion of coal resources, improving the utilization and efficiency of resources, whilst reducing CO2 emissions is a key area for further development and investigation by the coal chemical industry. Under a weak carbon mitigation policy, the value and price of products from coal conversion are suggested in the carbon cycle.

  16. A framework for assessing global change risks to forest carbon stocks in the United States

    Science.gov (United States)

    Christopher W. Woodall; Grant M. Domke; Karin L. Riley; Christopher M. Oswalt; Susan J. Crocker; Gary W. Yohe

    2013-01-01

    Among terrestrial environments, forests are not only the largest long-term sink of atmospheric carbon (C), but are also susceptible to global change themselves, with potential consequences including alterations of C cycles and potential C emission. To inform global change risk assessment of forest C across large spatial/temporal scales, this study constructed and...

  17. Using FIA and landsat observations to improve the spatial and temporal resolution of forest carbon estimates

    Science.gov (United States)

    Karen Schleeweis; Chengquan Huang; Khaldoun Rishmawi; Feng Aron Zhao; Jeffery G. Masek; Richard K. Houghton; Samuel N. Goward

    2015-01-01

    For nearly a decade, the USFS FIA, NASA, and the University of Maryland have collaborated on the NASA/NACP funded North American Forest Dynamics (NAFD) project, and developed new approaches for annual mapping of CONUS forest dynamics (1984-2011). Building on this foundation of empirical research and results, the collaboration will continue with a new Carbon Cycle...

  18. Carbon pools and fluxes in small temperate forest landscapes: Variability and implications for sampling design

    Science.gov (United States)

    John B. Bradford; Peter Weishampel; Marie-Louise Smith; Randall Kolka; Richard A. Birdsey; Scott V. Ollinger; Michael G. Ryan

    2010-01-01

    Assessing forest carbon storage and cycling over large areas is a growing challenge that is complicated by the inherent heterogeneity of forest systems. Field measurements must be conducted and analyzed appropriately to generate precise estimates at scales large enough for mapping or comparison with remote sensing data. In this study we examined...

  19. Soil carbon model alternatives for ECHAM5/JSBACH climate model: Evaluation and impacts on global carbon cycle estimates

    DEFF Research Database (Denmark)

    Thum, T.; Raisanen, P.; Sevanto, S.

    2011-01-01

    model formulation produced soil carbon stock estimates that were much closer to measured values. It also captured better the seasonal cycle of the direct CO2 exchange measurements at the three grassland sites considered (RMS error reduced by 12%), while for the five forest sites also analyzed......The response of soil organic carbon to climate change might lead to significant feedbacks affecting global warming. This response can be studied by coupled climate-carbon cycle models but so far the description of soil organic carbon cycle in these models has been quite simple. In this work we used...... the coupled climate-carbon cycle model ECHAM5/JSBACH (European Center/Hamburg Model 5/Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg) with two different soil carbon modules, namely (1) the original soil carbon model of JSBACH called CBALANCE and (2) a new soil carbon model Yasso07, to study...

  20. The Effects of Insect Outbreak Disturbances on the North American Carbon Cycle: A Review

    Science.gov (United States)

    Hicke, J. A.; Hall, R. J.; Raffa, K.; Desai, A. R.; Kashian, D.

    2009-12-01

    Disturbances are important ecosystem processes that greatly affect carbon cycling. In forests, disturbances contribute to modifications to carbon stocks and fluxes by increasing the amount of decomposing dead organic matter and decreasing the amount of carbon taken up by the ecosystem through photosynthesis. The net effect immediately following a disturbance is that forest ecosystems are carbon sources to the atmosphere. Within several decades, the carbon source becomes a carbon sink as the dead wood decays and the forest regrows. In North America, insect outbreaks are major forest disturbances, killing millions of trees in bark beetle and defoliator outbreaks that range over millions of ha. This presentation will review the role that insect infestations have in the North American carbon budget. We summarize estimates of the extent, frequency, and severity of outbreaks and the uncertainty associated with how these estimates are derived. We describe drivers of insect epidemics, which include climate, stand-structure, and predator-prey interactions. Finally, we describe studies that have documented impacts to the carbon cycle by insect infestations and discuss ongoing efforts. Although the role of insect disturbances is not well documented, these forest disturbances appear to be major factors that need inclusion for robust estimates of contemporary carbon budgets and for prediction of future carbon cycling given feedbacks with climate change.

  1. Human energy use and the carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.L. [National Round Table on the Environment and the Economy (Canada)

    2001-07-01

    This paper discusses the close connection between human energy use and the Carbon Cycle. The movement of Carbon from the atmosphere to organic (living) matter and then back to atmosphere is called the Carbon Cycle and can be considered the basic infrastructure for life itself. In the process, some of the organic matter becomes trapped in the earth and in the oceans; some of what is trapped becomes, over millions of years, Carbon-based fuels known as 'fossil fuels'. This paper concludes that climate change is primarily an energy problem, not a pollution problem, and discusses various options and technologies to lower energy consumption.

  2. Opportunities for Human-induced Increases in Carbon Sequestration of North American Forests

    Science.gov (United States)

    Birdsey, R.; Pan, Y.

    2008-12-01

    According to the "State of the Carbon Cycle Report", North American forests were a net carbon sink of approximately -269 Mt C yr-1 over the last 10 to 15 years. The report highlighted that deforestation continues in Mexico where forests are a source of CO2 to the atmosphere; and that forests of the United States and parts of Canada have become a carbon sink as a consequence of the recovery of forests following the abandonment of agricultural land. Recent research suggests that CO2 emissions from Canada's forests are highly variable because of interannual changes in area burned by wildfire, and that future forests are likely to be net sources because of expected increasing carbon releases from insect epidemics. The size of the carbon sink in U.S. forests appears to be declining based on inventory data from 1952 to the present. With these estimates as a baseline, can land-use and forest management strategies adapt to significantly change the carbon sink strength of forest systems at the continental scale? The net effect of these strategies depends on the area of forests under active management, management objectives, and the disturbance regime. Here we review estimates of potential gains from managing land use and forests to increase carbon sequestration over baseline conditions. We attempt to identify a plausible "upper bound" of potential gains for North America, and discuss some of the likely approaches to implementing forest carbon management policies for Canada, the United States, and Mexico. We present a conceptual model of how to integrate the potentially contrasting objectives of increasing carbon sequestration while reducing the risk of loss of carbon from natural disturbances.

  3. Slow growth rates of Amazonian trees: Consequences for carbon cycling

    Science.gov (United States)

    Vieira, Simone; Trumbore, Susan; Camargo, Plinio B.; Selhorst, Diogo; Chambers, Jeffrey Q.; Higuchi, Niro; Martinelli, Luiz Antonio

    2005-01-01

    Quantifying age structure and tree growth rate of Amazonian forests is essential for understanding their role in the carbon cycle. Here, we use radiocarbon dating and direct measurement of diameter increment to document unexpectedly slow growth rates for trees from three locations spanning the Brazilian Amazon basin. Central Amazon trees, averaging only ≈1mm/year diameter increment, grow half as fast as those from areas with more seasonal rainfall to the east and west. Slow growth rates mean that trees can attain great ages; across our sites we estimate 17-50% of trees with diameter >10 cm have ages exceeding 300 years. Whereas a few emergent trees that make up a large portion of the biomass grow faster, small trees that are more abundant grow slowly and attain ages of hundreds of years. The mean age of carbon in living trees (60-110 years) is within the range of or slightly longer than the mean residence time calculated from C inventory divided by annual C allocation to wood growth (40-100 years). Faster C turnover is observed in stands with overall higher rates of diameter increment and a larger fraction of the biomass in large, fast-growing trees. As a consequence, forests can recover biomass relatively quickly after disturbance, whereas recovering species composition may take many centuries. Carbon cycle models that apply a single turnover time for carbon in forest biomass do not account for variations in life strategy and therefore may overestimate the carbon sequestration potential of Amazon forests. PMID:16339903

  4. A tale of two "forests": random forest machine learning AIDS tropical forest carbon mapping.

    Science.gov (United States)

    Mascaro, Joseph; Asner, Gregory P; Knapp, David E; Kennedy-Bowdoin, Ty; Martin, Roberta E; Anderson, Christopher; Higgins, Mark; Chadwick, K Dana

    2014-01-01

    Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including--in the latter case--x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called "out-of-bag"), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha(-1) when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation.

  5. A tale of two "forests": random forest machine learning AIDS tropical forest carbon mapping.

    Directory of Open Access Journals (Sweden)

    Joseph Mascaro

    Full Text Available Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus. The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including--in the latter case--x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called "out-of-bag", which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha(-1 when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation.

  6. Soil nitrogen cycling and nitrous oxide flux in a Rocky Mountain Douglas-fir forest - Effects of fertilization, irrigation and carbon addition

    Science.gov (United States)

    Matson, Pamela A.; Gower, Stith T.; Volkmann, Carol; Billow, Christine; Grier, Charles C.

    1992-01-01

    Nitrous oxide fluxes and soil nitrogen transformations were measured in experimentally-treated high elevation Douglas-fir forests in northwestern New Mexico. On an annual basis, forests that were fertilized with 200 kg N/ha emitted an average of 0.66 kg/ha of N2O-N, with highest fluxes occurring in July and August when soils were both warm and wet. Control, irrigated, and woodchip treated plots were not different from each other, and annual average fluxes ranged from 0.03 to 0.23 kg/ha. Fertilized soil mineralized 277 kg/ha per year in contrast to 18 kg/ha per year in control plots. Relative recovery of (N-15)H4-N applied to soil in laboratory incubations was principally in the form of NO3-N in the fertilized soils, while recovery was mostly in microbial biomass-N in the other treatments. Fertilization apparently added nitrogen that exceeded the heterotrophic microbial demand, resulting in higher rates of nitrate production and higher nitrous oxide fluxes. Global inputs of nitrogen into forests are not currently contributing significantly to the increasing concentrations of nitrous oxide in the atmosphere.

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

    Science.gov (United States)

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

    2014-06-01

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

  8. Africa and the global carbon cycle

    CSIR Research Space (South Africa)

    Williams, CA

    2007-03-01

    Full Text Available The African continent has a large and growing role in the global carbon cycle, with potentially important climate change implications. However, the sparse observation network in and around the African continent means that Africa is one...

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

    Science.gov (United States)

    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. Carbon dynamics of intensively managed forest along a full rotation

    Science.gov (United States)

    Moreaux, V.; Bosc, A.; Bonnefond, J.; Burlett, R.; Lamaud, E.; Sartore, M.; Trichet, P.; Chipeaux, C.; Lambrot, C.; Kowalski, A. S.; Loustau, D.

    2012-12-01

    effects of the reduction of the LAI, the enhancement of the heterotrophic respiration related to the decomposition of dead materials and the improvement of the mineralization of the large stock of soil organic matter by tillage. At the mature stage, the stand remains consistently a carbon sink and CO2 fluxes were insensitive to thinning. Conversely, the carbon balance was sensitive to climate effects as evidenced by repeated drastic reductions in NEP caused by soil drought. Our data underlines the importance of disturbances linked to forest management for the forest carbon balance during the early stage of tree growth. Since management intensification tends to shorten the forest life cycle and enhance the share of the young stages, our results confirm that the consequence of management operations on the carbon cycle in forest may revert intensified forest stands from a net sink to a source and should be accounted for carefully.

  11. Assessment of Major Pools and Fluxes of Carbon in Indian Forests

    Energy Technology Data Exchange (ETDEWEB)

    Chhabra, A.; Dadhwal, V.K. [Agricultural Resources Group, Remote Sensing Applications Area, Space Applications Centre (ISRO), 380 015 Ahmedabad (India)

    2004-07-01

    The major pools including phytomass, soil, litter, and fluxes of carbon (C) due to litterfall and landuse changes were estimated for Indian forests. Based on growing stock-volume approach at the state and district levels, the Indian forest phytomass was estimated in the range of 3.8-4.3 PgC. The total soil organic pool in the top 1m depth was estimated as 6.8 PgC, using estimated soil organic carbon densities and Remote Sensing (RS) based area by forest types. Based on 122 published Indian studies and RS-based forest area, the total litterfall carbon flux was estimated as 208.8 MgC ha-1 yr-1. The cumulative net carbon flux (1880-1996) from Indian forests (1880-1996) due to landuse changes (deforestation, afforestation and phytomass degradation) was estimated as 5.4 PgC, using a simple book-keeping approach. The mean annual net C flux due to landuse changes during 1985-1996 was estimated as 9.0 TgC yr-1. For the recent period, the Indian forests are nationally a small source with some regions acting as small sinks of carbon as well. The improved quantification of pools and fluxes related to forest carbon cycle is important for understanding the contribution of Indian forests to net carbon emissions as well as their potential for carbon sequestration in the context of the Kyoto protocol.

  12. Simulated impacts of insect defoliation on forest carbon dynamics

    Science.gov (United States)

    Medvigy, D.; Clark, K. L.; Skowronski, N. S.; Schäfer, K. V. R.

    2012-12-01

    Many temperate and boreal forests are subject to insect epidemics. In the eastern US, over 41 million meters squared of tree basal area are thought to be at risk of gypsy moth defoliation. However, the decadal-to-century scale implications of defoliation events for ecosystem carbon dynamics are not well understood. In this study, the effects of defoliation intensity, periodicity and spatial pattern on the carbon cycle are investigated in a set of idealized model simulations. A mechanistic terrestrial biosphere model, ecosystem demography model 2, is driven with observations from a xeric oak-pine forest located in the New Jersey Pine Barrens. Simulations indicate that net ecosystem productivity (equal to photosynthesis minus respiration) decreases linearly with increasing defoliation intensity. However, because of interactions between defoliation and drought effects, aboveground biomass exhibits a nonlinear decrease with increasing defoliation intensity. The ecosystem responds strongly with both reduced productivity and biomass loss when defoliation periodicity varies from 5 to 15 yr, but exhibits a relatively weak response when defoliation periodicity varies from 15 to 60 yr. Simulations of spatially heterogeneous defoliation resulted in markedly smaller carbon stocks than simulations with spatially homogeneous defoliation. These results show that gypsy moth defoliation has a large effect on oak-pine forest biomass dynamics, functioning and its capacity to act as a carbon sink.

  13. Carbon stocks and changes on Pacific Northwest national forests and the role of disturbance, management, and growth

    Science.gov (United States)

    Andrew N. Gray; Thomas R. Whittier

    2014-01-01

    The National Forest System (NFS) of the United States plays an important role in the carbon cycle because these lands make up a large proportion of the forested land in the country and commonly store more wood per unit area than other forest ownerships. In addition to sustaining natural resources, these lands are managed for multiple objectives that do not always align...

  14. Interglacials, Milankovitch Cycles, and Carbon Dioxide

    CERN Document Server

    Marsh, Gerald E

    2010-01-01

    The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent work challenges the fundamental basis of these conceptions.

  15. Forest cutting and impacts on carbon in the eastern United States

    Science.gov (United States)

    Zhou, Decheng; Liu, Shuguang; Oeding, Jennifer; Zhao, Shuqing

    2013-12-01

    Forest cutting is a major anthropogenic disturbance that affects forest carbon (C) storage and fluxes. Yet its characteristics and impacts on C cycling are poorly understood over large areas. Using recent annualized forest inventory data, we estimated cutting-related loss of live biomass in the eastern United States was 168 Tg C yr-1 from 2002 to 2010 (with C loss per unit forest area of 1.07 Mg ha-1 yr-1), which is equivalent to 70% of the total U.S. forest C sink or 11% of the national annual CO2 emissions from fossil-fuel combustion over the same period. We further revealed that specific cutting-related C loss varied with cutting intensities, forest types, stand ages, and geographic locations. Our results provide new insights to the characteristics of forest harvesting activities in the eastern United States and highlight the significance of partial cutting to regional and national carbon budgets.

  16. Recuperative supercritical carbon dioxide cycle

    Science.gov (United States)

    Sonwane, Chandrashekhar; Sprouse, Kenneth M; Subbaraman, Ganesan; O'Connor, George M; Johnson, Gregory A

    2014-11-18

    A power plant includes a closed loop, supercritical carbon dioxide system (CLS-CO.sub.2 system). The CLS-CO.sub.2 system includes a turbine-generator and a high temperature recuperator (HTR) that is arranged to receive expanded carbon dioxide from the turbine-generator. The HTR includes a plurality of heat exchangers that define respective heat exchange areas. At least two of the heat exchangers have different heat exchange areas.

  17. Permafrost soils and carbon cycling

    OpenAIRE

    Ping, C. L.; J. D. Jastrow; Jorgenson, M. T.; G. J. Michaelson; Y. L. Shur

    2015-01-01

    Knowledge of soils in the permafrost region has advanced immensely in recent decades, despite the remoteness and inaccessibility of most of the region and the sampling limitations posed by the severe environment. These efforts significantly increased estimates of the amount of organic carbon stored in permafrost-region soils and improved understanding of how pedogenic processes unique to permafrost environments built enormous organic carbon stocks during the Quaternary. This...

  18. Fire dynamics and implications for nitrogen cycling in boreal forests

    Science.gov (United States)

    Harden, Jennifer W.; Mack, Michelle; Veldhuis, Hugo; Gower, S. T.

    2003-02-01

    We used a dynamic, long-term mass balance approach to track cumulative carbon (C) and nitrogen (N) losses to fire in boreal Manitoba over the 6500 years since deglaciation. Estimated C losses to decomposition and fire, combined with measurements of N pools in mature and burned forest floors, suggest that loss of N by combustion has likely resulted in a long-term loss that exceeds the amount of N stored in soil today by 2 to 3 times. These estimates imply that biological N fixation rates could be as high as 5 to 10 times atmospheric deposition rates in boreal regions. At the site scale, the amount of N lost is due to N content of fuels, which varies by stand type and fire severity, which in turn vary with climate and fire dynamics. The interplay of fire frequency, fire severity, and N partitioning during regrowth are important for understanding rates and sustainability of nutrient and carbon cycling over millenia and over broad regions.

  19. Cycling of black carbon in the ocean

    OpenAIRE

    2016-01-01

    Black carbon (BC) is a byproduct of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial timescales in the world oceans has remained unknown. Here, we quantified dissolved BC (DBC) in marine dissolved organic carbon (DOC) isolated by solid phase extraction (SPE) at several sites in the world ocean. We find that DBC in the Atlantic, Pacific and Arctic oceans ranges from 1.4 to 2.6 μM in the surface and is ...

  20. Cycling of black carbon in the ocean

    OpenAIRE

    Coppola, Alysha I; Druffel, Ellen R. M.

    2016-01-01

    Black carbon (BC) is a byproduct of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial timescales in the world oceans has remained unknown. Here, we quantified dissolved BC (DBC) in marine dissolved organic carbon (DOC) isolated by solid phase extraction (SPE) at several sites in the world ocean. We find that DBC in the Atlantic, Pacific and Arctic oceans ranges from 1.4 to 2.6 μM in the surface and is ...

  1. Climate seasonality limits leaf carbon assimilation and wood productivity in tropical forests

    Science.gov (United States)

    Wagner, Fabien H.; Hérault, Bruno; Bonal, Damien; Stahl, Clément; Anderson, Liana O.; Baker, Timothy R.; Becker, Gabriel Sebastian; Beeckman, Hans; Boanerges Souza, Danilo; Botosso, Paulo Cesar; Bowman, David M. J. S.; Bräuning, Achim; Brede, Benjamin; Irving Brown, Foster; Julio Camarero, Jesus; Barbosa Camargo, Plínio; Cardoso, Fernanda C. G.; Alvim Carvalho, Fabrício; Castro, Wendeson; Koloski Chagas, Rubens; Chave, Jérome; Chidumayo, Emmanuel N.; Clark, Deborah A.; Capellotto Costa, Flavia Regina; Couralet, Camille; Henrique da Silva Mauricio, Paulo; Dalitz, Helmut; Resende de Castro, Vinicius; Eloisa de Freitas Milani, Jaçanan; Consuelo de Oliveira, Edilson; de Souza Arruda, Luciano; Devineau, Jean-Louis; Drew, David M.; Dünisch, Oliver; Durigan, Giselda; Elifuraha, Elisha; Fedele, Marcio; Ferreira Fedele, Ligia; Figueiredo Filho, Afonso; Guimarães Finger, César Augusto; César Franco, Augusto; Lima Freitas Júnior, João; Galvão, Franklin; Gebrekirstos, Aster; Gliniars, Robert; Maurício Lima de Alencastro Graça, Paulo; Griffiths, Anthony D.; Grogan, James; Guan, Kaiyu; Homeier, Jürgen; Raquel Kanieski, Maria; Khoon Kho, Lip; Koenig, Jennifer; Valerio Kohler, Sintia; Krepkowski, Julia; Pires Lemos-Filho, José; Lieberman, Diana; Lieberman, Milton Eugene; Lisi, Claudio Sergio; Longhi Santos, Tomaz; López Ayala, José Luis; Eijji Maeda, Eduardo; Malhi, Yadvinder; Maria, Vivian R. B.; Marques, Marcia C. M.; Marques, Renato; Maza Chamba, Hector; Mbwambo, Lawrence; Liana Lisboa Melgaço, Karina; Mendivelso, Hooz Angela; Murphy, Brett P.; O'Brien, Joseph J.; Oberbauer, Steven F.; Okada, Naoki; Pélissier, Raphaël; Prior, Lynda D.; Alejandro Roig, Fidel; Ross, Michael; Rodrigo Rossatto, Davi; Rossi, Vivien; Rowland, Lucy; Rutishauser, Ervan; Santana, Hellen; Schulze, Mark; Selhorst, Diogo; Rodrigues Silva, Williamar; Silveira, Marcos; Spannl, Susanne; Swaine, Michael D.; Julio Toledo, José; Toledo, Marcos Miranda; Toledo, Marisol; Toma, Takeshi; Tomazello Filho, Mario; Valdez Hernández, Juan Ignacio; Verbesselt, Jan; Aparecida Vieira, Simone; Vincent, Grégoire; Volkmer de Castilho, Carolina; Volland, Franziska; Worbes, Martin; Bolzan Zanon, Magda Lea; Aragão, Luiz E. O. C.

    2016-04-01

    The seasonal climate drivers of the carbon cycle in tropical forests remain poorly known, although these forests account for more carbon assimilation and storage than any other terrestrial ecosystem. Based on a unique combination of seasonal pan-tropical data sets from 89 experimental sites (68 include aboveground wood productivity measurements and 35 litter productivity measurements), their associated canopy photosynthetic capacity (enhanced vegetation index, EVI) and climate, we ask how carbon assimilation and aboveground allocation are related to climate seasonality in tropical forests and how they interact in the seasonal carbon cycle. We found that canopy photosynthetic capacity seasonality responds positively to precipitation when rainfall is < 2000 mm yr-1 (water-limited forests) and to radiation otherwise (light-limited forests). On the other hand, independent of climate limitations, wood productivity and litterfall are driven by seasonal variation in precipitation and evapotranspiration, respectively. Consequently, light-limited forests present an asynchronism between canopy photosynthetic capacity and wood productivity. First-order control by precipitation likely indicates a decrease in tropical forest productivity in a drier climate in water-limited forest, and in current light-limited forest with future rainfall < 2000 mm yr-1.

  2. Water-carbon Links in a Tropical Forest: How Interbasin Groundwater Flow Affects Carbon Fluxes and Ecosystem Carbon Budgets

    Energy Technology Data Exchange (ETDEWEB)

    Genereux, David [NC State University; Osburn, Christopher [NC State University; Oberbauer, Steven [Florida International University; Oviedo Vargas, Diana [NC State University; Dierick, Diego [Florida International University

    2017-03-27

    This report covers the outcomes from a quantitative, interdisciplinary field investigation of how carbon fluxes and budgets in a lowland tropical rainforest are affected by the discharge of old regional groundwater into streams, springs, and wetlands in the forest. The work was carried out in a lowland rainforest of Costa Rica, at La Selva Biological Station. The research shows that discharge of regional groundwater high in dissolved carbon dioxide represents a significant input of carbon to the rainforest "from below", an input that is on average larger than the carbon input "from above" from the atmosphere. A stream receiving discharge of regional groundwater had greatly elevated emissions of carbon dioxide (but not methane) to the overlying air, and elevated downstream export of carbon from its watershed with stream flow. The emission of deep geological carbon dioxide from stream water elevates the carbon dioxide concentrations in air above the streams. Carbon-14 tracing revealed the presence of geological carbon in the leaves and stems of some riparian plants near streams that receive inputs of regional groundwater. Also, discharge of regional groundwater is responsible for input of dissolved organic matter with distinctive chemistry to rainforest streams and wetlands. The discharge of regional groundwater in lowland surface waters has a major impact on the carbon cycle in this and likely other tropical and non-tropical forests.

  3. Future forest carbon accounting challenges: the question of regionalization

    Science.gov (United States)

    Michael C. Nichols

    2015-01-01

    Forest carbon accounting techniques are changing. This year, a new accounting system is making its debut with the production of forest carbon data for EPA’s National Greenhouse Gas Inventory. The Forest Service’s annualized inventory system is being more fully integrated into estimates of forest carbon at the national and state levels both for the present and the...

  4. Chemical Oceanography and the Marine Carbon Cycle

    Science.gov (United States)

    Emerson, Steven; Hedges, John

    The principles of chemical oceanography provide insight into the processes regulating the marine carbon cycle. The text offers a background in chemical oceanography and a description of how chemical elements in seawater and ocean sediments are used as tracers of physical, biological, chemical and geological processes in the ocean. The first seven chapters present basic topics of thermodynamics, isotope systematics and carbonate chemistry, and explain the influence of life on ocean chemistry and how it has evolved in the recent (glacial-interglacial) past. This is followed by topics essential to understanding the carbon cycle, including organic geochemistry, air-sea gas exchange, diffusion and reaction kinetics, the marine and atmosphere carbon cycle and diagenesis in marine sediments. Figures are available to download from www.cambridge.org/9780521833134. Ideal as a textbook for upper-level undergraduates and graduates in oceanography, environmental chemistry, geochemistry and earth science and a valuable reference for researchers in oceanography.

  5. Spatio-temporal changes in biomass carbon sinks in China's forests from 1977 to 2008.

    Science.gov (United States)

    Guo, Zhaodi; Hu, Huifeng; Li, Pin; Li, Nuyun; Fang, Jingyun

    2013-07-01

    Forests play a leading role in regional and global carbon (C) cycles. Detailed assessment of the temporal and spatial changes in C sinks/sources of China's forests is critical to the estimation of the national C budget and can help to constitute sustainable forest management policies for climate change. In this study, we explored the spatio-temporal changes in forest biomass C stocks in China between 1977 and 2008, using six periods of the national forest inventory data. According to the definition of the forest inventory, China's forest was categorized into three groups: forest stand, economic forest, and bamboo forest. We estimated forest biomass C stocks for each inventory period by using continuous biomass expansion factor (BEF) method for forest stands, and the mean biomass density method for economic and bamboo forests. As a result, China's forests have accumulated biomass C (i.e., biomass C sink) of 1896 Tg (1 Tg=10(12) g) during the study period, with 1710, 108 and 78 Tg C in forest stands, and economic and bamboo forests, respectively. Annual forest biomass C sink was 70.2 Tg C a(-1), offsetting 7.8% of the contemporary fossil CO2 emissions in the country. The results also showed that planted forests have functioned as a persistent C sink, sequestrating 818 Tg C and accounting for 47.8% of total C sink in forest stands, and that the old-, mid- and young-aged forests have sequestrated 930, 391 and 388 Tg C from 1977 to 2008. Our results suggest that China's forests have a big potential as biomass C sink in the future because of its large area of planted forests with young-aged growth and low C density.

  6. Atmospheric carbon dioxide and the global carbon cycle

    Energy Technology Data Exchange (ETDEWEB)

    Trabalka, J R [ed.

    1985-12-01

    This state-of-the-art volume presents discussions on the global cycle of carbon, the dynamic balance among global atmospheric CO2 sources and sinks. Separate abstracts have been prepared for the individual papers. (ACR)

  7. Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites

    NARCIS (Netherlands)

    Mitchard, Edward T. A.; Feldpausch, Ted R.; Brienen, Roel J. W.; Lopez-Gonzalez, Gabriela; Monteagudo, Abel; Baker, Timothy R.; Lewis, Simon L.; Lloyd, Jon; Quesada, Carlos A.; Gloor, Manuel; ter Steege, Hans|info:eu-repo/dai/nl/075217120; Meir, Patrick; Alvarez, Esteban; Araujo-Murakami, Alejandro; Aragao, Luiz E. O. C.; Arroyo, Luzmila; Aymard, Gerardo; Banki, Olaf; Bonal, Damien; Brown, Sandra; Brown, Foster I.; Ceron, Carlos E.; Chama Moscoso, Victor; Chave, Jerome; Comiskey, James A.; Cornejo, Fernando; Corrales Medina, Massiel; Da Costa, Lola; Costa, Flavia R. C.; Di Fiore, Anthony; Domingues, Tomas F.; Erwin, Terry L.; Frederickson, Todd; Higuchi, Niro; Honorio Coronado, Euridice N.; Levis, Carolina; Killeen, Tim J.; Laurance, William F.; Magnusson, William E.; Marimon, Beatriz S.; Marimon Junior, Ben Hur; Mendoza Polo, Irina; Mishra, Piyush; Nascimento, Marcelo T.; Neill, David; Nunez Vargas, Mario P.; Palacios, Walter A.; Parada, Alexander; Pardo Molina, Guido; Pena-Claros, Marielos; Pitman, Nigel; Peres, Carlos A.; Prieto, Adriana; Poorter, Lourens; Ramirez-Angulo, Hirma; Restrepo Correa, Zorayda; Roopsind, Anand; Roucoux, Katherine H.; Rudas, Agustin; Salomao, Rafael P.; Schietti, Juliana; Silveira, Marcos; de Souza, Priscila F.; Steininger, Marc K.; Stropp, Juliana; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van Andel, Tinde R.|info:eu-repo/dai/nl/205284868; van der Heijden, Geertje M. F.; Vieira, Ima C. G.; Vieira, Simone; Vilanova-Torre, Emilio; Vos, Vincent A.; Wang, Ophelia; Zartman, Charles E.; Malhi, Yadvinder; Phillips, Oliver L.; Cruz, A.P.; Cuenca, W.P.; Espejo, J.E.; Ferreira, L.; Germaine, A.; Penuela, M.C.; Silva, N.; Valenzuela Gamarra, L.

    Aim The accurate mapping of forest carbon stocks is essential for understanding the global carbon cycle, for assessing emissions from deforestation, and for rational land-use planning. Remote sensing (RS) is currently the key tool for this purpose, but RS does not estimate vegetation biomass

  8. Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites

    NARCIS (Netherlands)

    Mitchard, Edward T. A.; Feldpausch, Ted R.; Brienen, Roel J. W.; Lopez-Gonzalez, Gabriela; Monteagudo, Abel; Baker, Timothy R.; Lewis, Simon L.; Lloyd, Jon; Quesada, Carlos A.; Gloor, Manuel; ter Steege, Hans; Meir, Patrick; Alvarez, Esteban; Araujo-Murakami, Alejandro; Aragao, Luiz E. O. C.; Arroyo, Luzmila; Aymard, Gerardo; Banki, Olaf; Bonal, Damien; Brown, Sandra; Brown, Foster I.; Ceron, Carlos E.; Chama Moscoso, Victor; Chave, Jerome; Comiskey, James A.; Cornejo, Fernando; Corrales Medina, Massiel; Da Costa, Lola; Costa, Flavia R. C.; Di Fiore, Anthony; Domingues, Tomas F.; Erwin, Terry L.; Frederickson, Todd; Higuchi, Niro; Honorio Coronado, Euridice N.; Levis, Carolina; Killeen, Tim J.; Laurance, William F.; Magnusson, William E.; Marimon, Beatriz S.; Marimon Junior, Ben Hur; Mendoza Polo, Irina; Mishra, Piyush; Nascimento, Marcelo T.; Neill, David; Nunez Vargas, Mario P.; Palacios, Walter A.; Parada, Alexander; Pardo Molina, Guido; Pena-Claros, Marielos; Pitman, Nigel; Peres, Carlos A.; Prieto, Adriana; Poorter, Lourens; Ramirez-Angulo, Hirma; Restrepo Correa, Zorayda; Roopsind, Anand; Roucoux, Katherine H.; Rudas, Agustin; Salomao, Rafael P.; Schietti, Juliana; Silveira, Marcos; de Souza, Priscila F.; Steininger, Marc K.; Stropp, Juliana; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van Andel, Tinde R.; van der Heijden, Geertje M. F.; Vieira, Ima C. G.; Vieira, Simone; Vilanova-Torre, Emilio; Vos, Vincent A.; Wang, Ophelia; Zartman, Charles E.; Malhi, Yadvinder; Phillips, Oliver L.; Cruz, A.P.; Cuenca, W.P.; Espejo, J.E.; Ferreira, L.; Germaine, A.; Penuela, M.C.; Silva, N.; Valenzuela Gamarra, L.

    2014-01-01

    Aim The accurate mapping of forest carbon stocks is essential for understanding the global carbon cycle, for assessing emissions from deforestation, and for rational land-use planning. Remote sensing (RS) is currently the key tool for this purpose, but RS does not estimate vegetation biomass directl

  9. Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites

    NARCIS (Netherlands)

    Mitchard, Edward T. A.; Feldpausch, Ted R.; Brienen, Roel J. W.; Lopez-Gonzalez, Gabriela; Monteagudo, Abel; Baker, Timothy R.; Lewis, Simon L.; Lloyd, Jon; Quesada, Carlos A.; Gloor, Manuel; ter Steege, Hans|info:eu-repo/dai/nl/075217120; Meir, Patrick; Alvarez, Esteban; Araujo-Murakami, Alejandro; Aragao, Luiz E. O. C.; Arroyo, Luzmila; Aymard, Gerardo; Banki, Olaf; Bonal, Damien; Brown, Sandra; Brown, Foster I.; Ceron, Carlos E.; Chama Moscoso, Victor; Chave, Jerome; Comiskey, James A.; Cornejo, Fernando; Corrales Medina, Massiel; Da Costa, Lola; Costa, Flavia R. C.; Di Fiore, Anthony; Domingues, Tomas F.; Erwin, Terry L.; Frederickson, Todd; Higuchi, Niro; Honorio Coronado, Euridice N.; Levis, Carolina; Killeen, Tim J.; Laurance, William F.; Magnusson, William E.; Marimon, Beatriz S.; Marimon Junior, Ben Hur; Mendoza Polo, Irina; Mishra, Piyush; Nascimento, Marcelo T.; Neill, David; Nunez Vargas, Mario P.; Palacios, Walter A.; Parada, Alexander; Pardo Molina, Guido; Pena-Claros, Marielos; Pitman, Nigel; Peres, Carlos A.; Prieto, Adriana; Poorter, Lourens; Ramirez-Angulo, Hirma; Restrepo Correa, Zorayda; Roopsind, Anand; Roucoux, Katherine H.; Rudas, Agustin; Salomao, Rafael P.; Schietti, Juliana; Silveira, Marcos; de Souza, Priscila F.; Steininger, Marc K.; Stropp, Juliana; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van Andel, Tinde R.|info:eu-repo/dai/nl/205284868; van der Heijden, Geertje M. F.; Vieira, Ima C. G.; Vieira, Simone; Vilanova-Torre, Emilio; Vos, Vincent A.; Wang, Ophelia; Zartman, Charles E.; Malhi, Yadvinder; Phillips, Oliver L.; Cruz, A.P.; Cuenca, W.P.; Espejo, J.E.; Ferreira, L.; Germaine, A.; Penuela, M.C.; Silva, N.; Valenzuela Gamarra, L.

    2014-01-01

    Aim The accurate mapping of forest carbon stocks is essential for understanding the global carbon cycle, for assessing emissions from deforestation, and for rational land-use planning. Remote sensing (RS) is currently the key tool for this purpose, but RS does not estimate vegetation biomass directl

  10. Biomass and carbon attributes of downed woody materials in forests of the United States

    Science.gov (United States)

    C.W. Woodall; B.F. Walters; S.N. Oswalt; G.M. Domke; C. Toney; A.N. Gray

    2013-01-01

    Due to burgeoning interest in the biomass/carbon attributes of forest downed and dead woody materials (DWMs) attributable to its fundamental role in the carbon cycle, stand structure/diversity, bioenergy resources, and fuel loadings, the U.S. Department of Agriculture has conducted a nationwide field-based inventory of DWM. Using the national DWM inventory, attributes...

  11. A carbon cycle science update since IPCC AR-4.

    Science.gov (United States)

    Dolman, A J; van der Werf, G R; van der Molen, M K; Ganssen, G; Erisman, J-W; Strengers, B

    2010-01-01

    We review important advances in our understanding of the global carbon cycle since the publication of the IPCC AR4. We conclude that: the anthropogenic emissions of CO2 due to fossil fuel burning have increased up through 2008 at a rate near to the high end of the IPCC emission scenarios; there are contradictory analyses whether an increase in atmospheric fraction, that might indicate a declining sink strength of ocean and/or land, exists; methane emissions are increasing, possibly through enhanced natural emission from northern wetland, methane emissions from dry plants are negligible; old-growth forest take up more carbon than expected from ecological equilibrium reasoning; tropical forest also take up more carbon than previously thought, however, for the global budget to balance, this would imply a smaller uptake in the northern forest; the exchange fluxes between the atmosphere and ocean are increasingly better understood and bottom up and observation-based top down estimates are getting closer to each other; the North Atlantic and Southern ocean take up less CO2, but it is unclear whether this is part of the 'natural' decadal scale variability; large-scale fires and droughts, for instance in Amazonia, but also at Northern latitudes, have lead to significant decreases in carbon uptake on annual timescales; the extra uptake of CO2 stimulated by increased N-deposition is, from a greenhouse gas forcing perspective, counterbalanced by the related additional N2O emissions; the amount of carbon stored in permafrost areas appears much (two times) larger than previously thought; preservation of existing marine ecosystems could require a CO2 stabilization as low as 450 ppm; Dynamic Vegetation Models show a wide divergence for future carbon trajectories, uncertainty in the process description, lack of understanding of the CO2 fertilization effect and nitrogen-carbon interaction are major uncertainties.

  12. Trends in nitrogen and phosphorus cycling are consistent and constrained during tropical secondary forest succession: is secondary forest young primary forest from a nutrient perspective?

    Science.gov (United States)

    Sullivan, B. W.; Nasto, M.; Alvarez-Clare, S.; Cole, R. J.; Reed, S.; Chazdon, R.; Davidson, E. A.; Cleveland, C. C.

    2015-12-01

    Extensive deforestation of tropical rainforest often leads to agricultural abandonment and secondary forest regeneration. The land area of secondary rainforest is soon likely to exceed that of primary forest, highlighting the importance of secondary tropical rainforest in the global carbon (C) cycle. Secondary forests often grow rapidly, but the role soil nutrients play in regulating secondary forest productivity remains unsettled. Consistent with biogeochemical theory, a landmark study from a set of sites in the Amazon Basin showed that secondary forests had low nitrogen (N) availability and relatively higher phosphorus (P) availability immediately after abandonment, but that as succession proceeded, N availability "recuperated" and there was relatively less P available. To address whether such changes in N and P availability during secondary forest growth are common, we reviewed 38 studies in lowland tropical rainforest that reported changes in 23 different metrics of N and P cycling during secondary succession. We calculated slopes (rates of change) during secondary succession for each metric in each study, and analyzed patterns in these rates of change. Significant trends during secondary succession were more evident in soils than in plants, but in most cases, the variability among studies was surprisingly low. Both soil N and P availability increased through succession, at least in surface soil. Such consistent changes imply substantial biogeochemical resilience of tropical forest soils in spite of differing land use histories and species compositions among studies. In most cases, slopes were similar whether primary forest was included in, or excluded from, our analysis, suggesting that secondary succession eventually leads to similar biogeochemical conditions as those found in primary forest. Our results suggesting consistent changes in N and P availability during succession provide a biogeochemical rationale for the conservation and restoration value of

  13. Global Carbon Cycle of the Precambrian Earth

    DEFF Research Database (Denmark)

    Wiewióra, Justyna

    The carbon isotopic composition of distinct Archaean geological records provides information about the global carbon cycle and emergence of life on early Earth. We utilized carbon isotopic records of Greenlandic carbonatites, diamonds, graphites, marbles, metacarbonates and ultramafic rocks...... to investigate carbon fluxes between Precambrian Earth’s mantle and crust and to trace the evolution of life in the Eoarchaean oceans. The world’s desire for diamonds gives us a unique opportunity to obtain insight into the nature of metasomatic fluids affecting the subcratonic lithospheric mantle (SCLM) beneath...

  14. Carbon density and distribution of six Chinese temperate forests

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Quantifying forest carbon(C) storage and distribution is important for forest C cycling studies and terrestrial ecosystem modeling.Forest inventory and allometric approaches were used to measure C density and allocation in six representative temperate forests of similar stand age(42-59 years old) and growing under the same climate in northeastern China.The forests were an aspen-birch forest,a hardwood forest,a Korean pine plantation,a Dahurian larch plantation,a mixed deciduous forest,and a Mongolian oak forest.There were no significant differences in the C densities of ecosystem components(except for detritus) although the six forests had varying vegetation compositions and site conditions.However,the differences were significant when the C pools were normalized against stand basal area.The total ecosystem C density varied from 186.9 tC hm-2 to 349.2 tC hm-2 across the forests.The C densities of vegetation,detritus,and soil ranged from 86.3-122.7 tC hm-2,6.5-10.5 tC hm-2,and 93.7-220.1 tC hm-2,respectively,which accounted for 39.7% ± 7.1%(mean ± SD),3.3% ± 1.1%,and 57.0% ± 7.9% of the total C densities,respectively.The overstory C pool accounted for > 99% of the total vegetation C pool.The foliage biomass,small root(diameter < 5mm) biomass,root-shoot ratio,and small root to foliage biomass ratio varied from 2.08-4.72 tC hm-2,0.95-3.24 tC hm-2,22.0%-28.3%,and 34.5%-122.2%,respectively.The Korean pine plantation had the lowest foliage production efficiency(total biomass/foliage biomass:22.6 g g-1) among the six forests,while the Dahurian larch plantation had the highest small root production efficiency(total biomass/small root biomass:124.7 g g-1).The small root C density decreased with soil depth for all forests except for the Mongolian oak forest,in which the small roots tended to be vertically distributed downwards.The C density of coarse woody debris was significantly less in the two plantations than in the four naturally regenerated forests.The variability

  15. Evolution of Sustainable Carbon Cycling Processes in China

    Institute of Scientific and Technical Information of China (English)

    Zhuang Yahui; Zhang Hongxun; Wang Xiaoke; Fang Jinyun

    2004-01-01

    This report summarizes the surveys on carbon inventories and initiatives on sustainable carbon cycling taken by RCEES. The first part of this report deals with the concept of sustainable carbon cycling, the historical evolution of carbon cycling processes in China, carbon pool enhancement, value addition, carbon sequestration and carbon balance.The second part covers the modeling of carbon dynamics, emission inventories of various carboncontaining greenhouse gases and their potential abatement measures.

  16. Carbon in boreal coniferous forest soil

    Energy Technology Data Exchange (ETDEWEB)

    Westman, C.J.; Ilvesniemi, H.; Liski, J.; Mecke, M. [Helsinki Univ. (Finland). Dept. of Forest Ecology; Fritze, H.; Helmisaari, H.S.; Pietikaeinen, J.; Smolander, A. [Finnish Forest Research Inst., Vantaa (Finland)

    1996-12-31

    The working hypothesis of the research was that the soil of boreal forests is a large carbon store and the amount of C is still increasing in young soils, like in the forest soils of Finland, which makes these soils important sinks for atmospheric CO{sub 2}. Since the processes defining the soil C balance, primary production of plants and decomposition, are dependent on environmental factors and site properties, it was assumed that the organic carbon pool in the soil is also dependent on the same factors. The soil C store is therefore likely to change in response to climatic warming. The aim of this research was to estimate the C balance of forest soil in Finland and predict changes in the balance in response to changes in climatic conditions. To achieve the aim (1) intensive empirical experimentation on the density of C in different pools in the soil and on fluxes between the pools was done was done, (2) the effect of site fertility and climate on the amount and properties of organic C in forest soil was investigated and (3) dynamic modelling for investigating dynamics of the soil C storage was used

  17. Modelling the carbon and nitrogen cycles

    Directory of Open Access Journals (Sweden)

    Costas A Varotsos

    2014-04-01

    Full Text Available The issues of air pollution are inextricably linked to the mechanisms underlying the physicochemical functioning of the biosphere which together with the atmosphere, the cryosphere, the lithosphere, and the hydrosphere constitute the climate system. We herewith present a review of the achievements and unresolved problems concerning the modeling of the biochemical cycles of basic chemicals of the climate system, such as carbon and nitrogen. Although the achievements in this area can roughly describe the carbon and nitrogen cycles, serious problems still remain associated with the accuracy and precision of the processes and assessments employed in the relevant modeling.

  18. Carbon cycling in terrestrial environments: Chapter 17

    Science.gov (United States)

    Wang, Yang; Huntington, Thomas G.; Osher, Laurie J.; Wassenaar, Leonard I; Trumbore, Susan E.; Amundson, Ronald; Harden, Jennifer W.; McKnight, Diane M.; Schiff, Sherry L.; Aiken, George R.; Lyons, W. Berry; Aravena, Ramon O.; Baron, Jill S.

    1998-01-01

    This chapter reviews a number of applications of isotopic techniques for the investigation of carbon cycling processes. Carbon dioxide (C02) is an important greenhouse gas. Its concentration in the atmosphere has increased from an estimated 270 ppm at the beginning of the industrial revolution to ∼ 360 ppm at present. Climatic conditions and atmospheric C02 concentration also influence isotopic discrimination during photosynthesis. Natural and anthropogenically induced variations in the carbon isotopic abundance can be exploited to investigate carbon transformations between pools on various time scales. It also discusses one of the isotopes of carbon, the 14C, that is produced in the atmosphere by interactions of cosmic-ray produced neutrons with stable isotopes of nitrogen (N), oxygen (O), and carbon (C), and has a natural abundance in the atmosphere of ∼1 atom 14 C per 1012 atoms 12C. The most important factor affecting the measured 14C ages of soil organic matter is the rate of organic carbon cycling in soils. Differences in the dynamics of soil carbon among different soils or soil horizons will result in different soil organic 14C signatures. As a result, the deviation of the measured 14C age from the true age could differ significantly among different soils or soil horizons.

  19. Implications of carbon dust emission for terrestrail carbon cycling and carbon accounting

    Science.gov (United States)

    Wind erosion preferentially removes the finest carbon- and nutrient-rich soil fractions, and consequently its role may be significant within terrestrial carbon (C) cycles. However, the impacts of wind erosion on soil organic carbon (SOC) redistribution are not considered in most carbon cycle models,...

  20. An assessment of forest landowner interest in selling forest carbon credits in the Lake States, USA

    Science.gov (United States)

    Kristell A. Miller; Stephanie A. Snyder; Michael A. Kilgore

    2012-01-01

    The nation's family forest lands can be an important contributor to carbon sequestration efforts. Yet very little is known about how family forest landowners view programs that enable them to sell carbon credits generated from the growth of their forest and the compensation that would be required to encourage a meaningful level of participation. To address this...

  1. Changes in the carbon cycle of Amazon ecosystems during the 2010 drought

    Energy Technology Data Exchange (ETDEWEB)

    Potter, Christopher [NASA Ames Research Center, Moffett Field, CA (United States); Klooster, Steven; Hiatt, Cyrus; Genovese, Vanessa [California State University Monterey Bay, Seaside, CA (United States); Castilla-Rubio, Juan Carlos, E-mail: chris.potter@nasa.gov [Planetary Skin Institute, Silicon Valley, CA (United States)

    2011-07-15

    Satellite remote sensing was combined with the NASA-CASA (Carnegie Ames Stanford Approach) carbon cycle simulation model to evaluate the impact of the 2010 drought (July through September) throughout tropical South America. Results indicated that net primary production in Amazon forest areas declined by an average of 7% in 2010 compared to 2008. This represented a loss of vegetation CO{sub 2} uptake and potential Amazon rainforest growth of nearly 0.5 Pg C in 2010. The largest overall decline in ecosystem carbon gains by land cover type was predicted for closed broadleaf forest areas of the Amazon river basin, including a large fraction of regularly flooded forest areas. Model results support the hypothesis that soil and dead wood carbon decomposition fluxes of CO{sub 2} to the atmosphere were elevated during the drought period of 2010 in periodically flooded forest areas, compared to those for forests outside the main river floodplains.

  2. Changes in the Carbon Cycle of Amazon Ecosystems During the 2010 Drought

    Science.gov (United States)

    Potter, Christophera; Klooster, Steven; Hiatt, Cyrus; Genovese, Vanessa; Castilla-Rubino, Juan Carlos

    2011-01-01

    Satellite remote sensing was combined with the NASA-CASA carbon cycle simulation model to evaluate the impact of the 2010 drought (July through September) throughout tropical South America. Results indicated that net primary production (NPP) in Amazon forest areas declined by an average of 7% in 2010 compared to 2008. This represented a loss of vegetation CO2 uptake and potential Amazon rainforest growth of nearly 0.5 Pg C in 2010. The largest overall decline in ecosystem carbon gains by land cover type was predicted for closed broadleaf forest areas of the Amazon River basin, including a large fraction of regularly flooded forest areas. Model results support the hypothesis that soil and dead wood carbon decomposition fluxes of CO2 to the atmosphere were elevated during the drought period of 2010 in periodically flooded forest areas, compared to forests outside the main river floodplains.

  3. Carbonizing forest governance: analyzing the consequences of REDD+ for multilevel forest governance

    NARCIS (Netherlands)

    Vijge, M.J.

    2016-01-01

    Carbonizing forest governance: Analyzing the consequences of REDD+ for multilevel forest governance Marjanneke J. Vijge Despite the fifty years of global action to combat deforestation and forest degradation, the world is still losing its forests at great scale. A

  4. Carbonizing forest governance: analyzing the consequences of REDD+ for multilevel forest governance

    NARCIS (Netherlands)

    Vijge, M.J.

    2016-01-01

    Carbonizing forest governance: Analyzing the consequences of REDD+ for multilevel forest governance Marjanneke J. Vijge Despite the fifty years of global action to combat deforestation and forest degradation, the world is still losing its forests at great scale. A

  5. Controls over aboveground forest carbon density on Barro Colorado Island, Panama

    Directory of Open Access Journals (Sweden)

    J. Mascaro

    2010-12-01

    Full Text Available Despite the importance of tropical forests to the global carbon cycle, ecological controls over landscape-level variation in live aboveground carbon density (ACD in tropical forests are poorly understood. Here, we conducted a spatially comprehensive analysis of ACD variation for a mainland tropical forest – Barro Colorado Island, Panama (BCI – and tested site factors that may control such variation. We mapped ACD over 98% of BCI (~1500 ha using airborne Light Detection and Ranging (LiDAR, which was well-correlated with ground-based measurements of ACD in Panamanian forests of various ages (r2 = 0.77, RMSE = 29 Mg C ha−1, P < 0.0001. We used multiple regression to examine controls over LiDAR-derived ACD, including slope angle, bedrock, soil texture, and forest age. Collectively, these variables explained 14% of the variation in ACD at 30-m resolution, and explained 33% at 100-m resolution. At all resolutions, slope (linked to underlying bedrock variation was the strongest driving factor; standing carbon stocks were generally higher on steeper slopes, where erosion rates tend to exceed weathering rates, compared to gentle slopes, where weathering in place produces deep, oxic soils. This result suggests that physiography may be more important in controlling ACD variation in Neotropical forests than currently thought. Although BCI has been largely undisturbed by humans for a century, past land-use over approximately half of the island still influences ACD variation, with younger forests (80–130 years old averaging ~15% less carbon storage than old-growth forests (>400 years old. If other regions of relatively old tropical secondary forests also store less carbon aboveground than primary forests, the effects on the global carbon cycle could be substantial and difficult to detect with satellite monitoring.

  6. Stand age and climate drive forest carbon balance recovery

    Science.gov (United States)

    Besnard, Simon; Carvalhais, Nuno; Clevers, Jan; Herold, Martin; Jung, Martin; Reichstein, Markus

    2016-04-01

    Forests play an essential role in the terrestrial carbon (C) cycle, especially in the C exchanges between the terrestrial biosphere and the atmosphere. Ecological disturbances and forest management are drivers of forest dynamics and strongly impact the forest C budget. However, there is a lack of knowledge on the exogenous and endogenous factors driving forest C recovery. Our analysis includes 68 forest sites in different climate zones to determine the relative influence of stand age and climate conditions on the forest carbon balance recovery. In this study, we only included forest regrowth after clear-cut stand replacement (e.g. harvest, fire), and afforestation/reforestation processes. We synthesized net ecosystem production (NEP), gross primary production (GPP), ecosystem respiration (Re), the photosynthetic respiratory ratio (GPP to Re ratio), the ecosystem carbon use efficiency (CUE), that is NEP to GPP ratio, and CUEclimax, where GPP is derived from the climate conditions. We implemented a non-linear regression analysis in order to identify the best model representing the C flux patterns with stand age. Furthermore, we showed that each C flux have a non-linear relationship with stand age, annual precipitation (P) and mean annual temperature (MAT), therefore, we proposed to use non-linear transformations of the covariates for C fluxes'estimates. Non-linear stand age and climate models were, therefore, used to establish multiple linear regressions for C flux predictions and for determining the contribution of stand age and climate in forest carbon recovery. Our findings depicted that a coupled stand age-climate model explained 33% (44%, average site), 62% (76%, average site), 56% (71%, average site), 41% (59%, average site), 50% (65%, average site) and 36% (50%, average site) of the variance of annual NEP, GPP, Re, photosynthetic respiratory ratio, CUE and CUEclimax across sites, respectively. In addition, we showed that gross fluxes (e.g. GPP and Re) are

  7. Forest biomass carbon stocks and variation in Tibet’s carbon-dense forests from 2001 to 2050

    Science.gov (United States)

    Sun, Xiangyang; Wang, Genxu; Huang, Mei; Chang, Ruiying; Ran, Fei

    2016-01-01

    Tibet’s forests, in contrast to China’s other forests, are characterized by primary forests, high carbon (C) density and less anthropogenic disturbance, and they function as an important carbon pool in China. Using the biomass C density data from 413 forest inventory sites and a spatial forest age map, we developed an allometric equation for the forest biomass C density and forest age to assess the spatial biomass C stocks and variation in Tibet’s forests from 2001 to 2050. The results indicated that the forest biomass C stock would increase from 831.1 Tg C in 2001 to 969.4 Tg C in 2050, with a net C gain of 3.6 Tg C yr−1 between 2001 and 2010 and a decrease of 1.9 Tg C yr−1 between 2040 and 2050. Carbon tends to allocate more in the roots of fir forests and less in the roots of spruce and pine forests with increasing stand age. The increase of the biomass carbon pool does not promote significant augmentation of the soil carbon pool. Our findings suggest that Tibet’s mature forests will remain a persistent C sink until 2050. However, afforestation or reforestation, especially with the larger carbon sink potential forest types, such as fir and spruce, should be carried out to maintain the high C sink capacity. PMID:27703215

  8. Climate change impact on the carbon cycle in Russian peatlands

    Science.gov (United States)

    Zavalishin, N. N.

    2009-04-01

    Dynamic compartment model with annual time resolution of carbon cycle functioning with elements of nitrogen and water cycles for three basic types of peatlands (oligotrophic, mesotrophic, eutrophic) is designed and verified based on data for several peatland ecosystems from Russian European part and Western Siberia as well as on estimates of relative areas occupied by these types in each of wetland provinces marked by Kats (1970). Flows between three main reservoirs and input-output fluxes can have donor-, recipient-, Volterra-controlled forms or be saturation functions of storages in participating reservoirs. Possible steady states of combined cycles allow to distinguish forest, forest-swamp and swamp for each of three types of peatland ecosystems as stable equilibria. Stability and bifurcation analysis of the dynamic model, as well as numerical modeling of transient non-equilibrium dynamic regimes, is carried out in the space of three parameters corresponding to intensities of atmospheric carbon assimilation by vegetation, output runoff from soils and litter, decay of dead organic matter by animals and microorganisms. These parameters depend on climatic magnitudes - annual temperature and total precipitation, soil moisture, availability of nitrogen in the litterfall. Atmospheric CO2 concentration increase can lead to appearance of oscillations in system compartments or to transition into other steady states depending on two other parameter values. Numerical simulations and analytical findings allow establish stability boundaries of each peatland type as an equilibrium of the model, and to calculate critical values of external parameters for which stable functioning of matter cycles is provided. Change in climatic or human perturbation parameters initiates a shift in the model parameter space corresponding to the temporal evolution of carbon cycle capable to change the ecosystem state significantly. Estimations of relative areas occupied by peatland types in some

  9. Potential of forest management to reduce French carbon emissions - regional modelling of the French forest carbon balance from the forest to the wood.

    Science.gov (United States)

    Valade, A.; Luyssaert, S.; Bellassen, V.; Vallet, P.

    2015-12-01

    In France the low levels of forest harvest (40 Mm3 per year over a volume increment of 89Mm3) is frequently cited to push for a more intensive management of the forest that would help reducing CO2 emissions. This reasoning overlooks the medium-to-long-term effects on the carbon uptake at the national scale that result from changes in the forest's structure and delayed emissions from products decay and bioenergy burning, both determinant for the overall C fluxes between the biosphere and the atmosphere. To address the impacts of an increase in harvest removal on biosphere-atmosphere carbon fluxes at national scale, we build a consistent regional modeling framework to integrate the forest-carbon system from photosynthesis to wood uses. We aim at bridging the gap between regional ecosystem modeling and land managers' considerations, to assess the synergistic and antagonistic effects of management strategies over C-based forest services: C-sequestration, energy and material provision, fossil fuel substitution. For this, we built on inventory data to develop a spatial forest growth simulator and design a novel method for diagnosing the current level of management based on stand characteristics (density, quadratic mean diameter or exploitability). The growth and harvest simulated are then processed with a life cycle analysis to account for wood transformation and uses. Three scenarii describe increases in biomass removals either driven by energy production target (set based on national prospective with a lock on minimum harvest diameters) or by changes in management practices (shorter or longer rotations, management of currently unmanaged forests) to be compared with business as usual simulations. Our management levels' diagnostics quantifies undermanagement at national scale and evidences the large weight of ownership-based undermanagement with an average of 26% of the national forest (between 10% and 40% per species) and thus represents a huge potential wood resource

  10. Does increasing rotation length lead to greater forest carbon storage?

    Science.gov (United States)

    Ter-Mikaelian, M. T.; Colombo, S. J.; Chen, J.

    2016-12-01

    Forest management is a key factor affecting climate change mitigation by forests. Increasing the age of harvesting (also referred to as rotation length) is a management practice that has been proposed as a means of increasing forest carbon sequestration and storage. However, studies of the effects of increasing harvest age on forest carbon stocks have mostly been limited to forest plantations. In contrast, this study assesses the effects of increased harvest age of managed natural forests of Ontario (Canada) at two scales. At the stand level, we assess merchantable volume yield curves to differentiate those for which increasing the age of harvest results in an increase in total forest carbon stocks versus those for which increased harvest age reduces carbon stocks. The stand level results are then applied to forest landscapes to demonstrate that the effect of increasing the age of harvest on forest carbon storage is specific to the forest growth rates for a given forest landscape and depends on the average age at which forests are harvested under current (business-as-usual) management practice. We discuss the implications of these results for forest management aimed at mitigating climate change.

  11. Global Carbon Cycle of the Precambrian Earth

    DEFF Research Database (Denmark)

    Wiewióra, Justyna

    to investigate carbon fluxes between Precambrian Earth’s mantle and crust and to trace the evolution of life in the Eoarchaean oceans. The world’s desire for diamonds gives us a unique opportunity to obtain insight into the nature of metasomatic fluids affecting the subcratonic lithospheric mantle (SCLM) beneath...... derived from surface water. Partitioning of carbon between 13C-rich oxidized and 13C-poor reduced species indicates that life in the early ocean had to be well evolved before 3.8 Ga. Therefore, the Isua ultramafic rocks may be considered as an indirect biomarker for ancient life.......The carbon isotopic composition of distinct Archaean geological records provides information about the global carbon cycle and emergence of life on early Earth. We utilized carbon isotopic records of Greenlandic carbonatites, diamonds, graphites, marbles, metacarbonates and ultramafic rocks...

  12. The carbon cycle in oceans; Le cycle du carbone dans les oceans

    Energy Technology Data Exchange (ETDEWEB)

    Dandonneau, Y. [Paris-6 Univ., CNRS, ORSTOM, 75 (France). Laboratoire d`Oceanographie Dynamique et de Climatologie

    1998-10-01

    Because of his activity, the human being increases the carbon dioxide emission and the greenhouse effect resulting. To forecast the consequences resulting from this increase, the scientists have to assess the ocean capacity to stock the carbon. This paper deals with the carbon dioxide emissions and with the possible methods to evaluate the carbon content on the various step of the cycle. (A.L.B.)

  13. Boreal forests and atmosphere - Biosphere exchange of carbon dioxide

    Science.gov (United States)

    D'Arrigo, Rosanne; Jacoby, Gordon C.; Fung, Inez Y.

    1987-01-01

    Two approaches to investigating the role of boreal forests in the global carbon cycle are presented. First, a tracer support model which incorporates the normalized-difference vegetation index obtained from advanced, very high resolution radiometer radiances was used to simulate the annual cycle of CO2 in the atmosphere. Results indicate that the seasonal growth of the combined boreal forests of North America and Eurasia accounts for about 50 percent of the mean seasonal CO2 amplitude recorded at Pt. Barrow, Alaska and about 30 percent of the more globally representative CO2 signal at Mauna Loa, Hawaii. Second, tree-ring width data from four boreal treeline sites in northern Canada were positively correlated with Pt. Barrow CO2 drawdown for the period 1971-1982. These results suggest that large-scale changes in the growth of boreal forests may be contributing to the observed increasing trend in CO2 amplitude. They further suggest that tree-ring data may be applicable as indices for CO2 uptake and remote sensing estimates of photosynthetic activity.

  14. Modelling the soil carbon cycle of pine ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Nakane, K. [Hiroshima, Univ., Dept. of Environ. Studies, Fac. of Integrated Arts and Sciences, Higashi Hiroshima (Japan)

    1994-12-31

    Soil carbon cycling rates and carbon budgets were calculated for stands of four pine species. Pinus sylvestris (at Jaedraaas, Sweden), P. densiflora (Hiroshima, Japan), P. elliottii (Florida, USA) and P. radiata (Canberra, Australia), using a simulation model driven by daily observations of mean air temperature and precipitation. Inputs to soil carbon through litterfall differ considerably among the four pine forests, but the accumulation of the A{sub 0} layer and humus in mineral soil is less variable. Decomposition of the A{sub 0} layer and humus is fastest for P. densiflora and slowest for P. sylvestris stands with P. radiata and P. elliottii intermediate. The decomposition rate is lower for the P. elliottii stand than for P. densiflora in spite of its higher temperatures and slightly higher precipitation. Seasonal changes in simulated soil carbon are observed only for the A{sub 0} layer at the P. densiflora site. Simulated soil respiration rates vary seasonally in three stands (P. sylvestris, P. densiflora and P. radiata). In simulations for pine trees planted on bare soil, all soil organic matter fractions except the humus in mineral soil recover to half their asymptotic values within 30 to 40 years of planting for P. sylvestris and P. densiflora, compared with 10 to 20 years for P. radiata and P. elliottii. The simulated recovery of soil carbon following clear-cutting is fastest for the P. elliottii stand and slowest for P. sylvestris. Management of P. elliottii and P. radiata stands on 40-years rotations is sustainable because carbon removed through harvest is restored in the interval between successive clear-cuts. However p. densiflora and P. sylvestris stands may be unable to maintain soil carbon under such a short rotation. High growth rates of P. elliottii and p. radiata stands in spite of relatively poor soil conditions and slow carbon cycling may be related to the physiological responses of species to environmental conditions. (Abstract Truncated)

  15. Zooplankton and the Ocean Carbon Cycle

    Science.gov (United States)

    Steinberg, Deborah K.; Landry, Michael R.

    2017-01-01

    Marine zooplankton comprise a phylogenetically and functionally diverse assemblage of protistan and metazoan consumers that occupy multiple trophic levels in pelagic food webs. Within this complex network, carbon flows via alternative zooplankton pathways drive temporal and spatial variability in production-grazing coupling, nutrient cycling, export, and transfer efficiency to higher trophic levels. We explore current knowledge of the processing of zooplankton food ingestion by absorption, egestion, respiration, excretion, and growth (production) processes. On a global scale, carbon fluxes are reasonably constrained by the grazing impact of microzooplankton and the respiratory requirements of mesozooplankton but are sensitive to uncertainties in trophic structure. The relative importance, combined magnitude, and efficiency of export mechanisms (mucous feeding webs, fecal pellets, molts, carcasses, and vertical migrations) likewise reflect regional variability in community structure. Climate change is expected to broadly alter carbon cycling by zooplankton and to have direct impacts on key species.

  16. Toward a Mexican eddy covariance network for carbon cycle science

    Science.gov (United States)

    Vargas, Rodrigo; Yépez, Enrico A.

    2011-09-01

    First Annual MexFlux Principal Investigators Meeting; Hermosillo, Sonora, Mexico, 4-8 May 2011; The carbon cycle science community has organized a global network, called FLUXNET, to measure the exchange of energy, water, and carbon dioxide (CO2) between the ecosystems and the atmosphere using the eddy covariance technique. This network has provided unprecedented information for carbon cycle science and global climate change but is mostly represented by study sites in the United States and Europe. Thus, there is an important gap in measurements and understanding of ecosystem dynamics in other regions of the world that are seeing a rapid change in land use. Researchers met under the sponsorship of Red Temática de Ecosistemas and Consejo Nacional de Ciencia y Tecnologia (CONACYT) to discuss strategies to establish a Mexican eddy covariance network (MexFlux) by identifying researchers, study sites, and scientific goals. During the meeting, attendees noted that 10 study sites have been established in Mexico with more than 30 combined years of information. Study sites span from new sites installed during 2011 to others with 9 to 6 years of measurements. Sites with the longest span measurements are located in Baja California Sur (established by Walter Oechel in 2002) and Sonora (established by Christopher Watts in 2005); both are semiarid ecosystems. MexFlux sites represent a variety of ecosystem types, including Mediterranean and sarcocaulescent shrublands in Baja California; oak woodland, subtropical shrubland, tropical dry forest, and a grassland in Sonora; tropical dry forests in Jalisco and Yucatan; a managed grassland in San Luis Potosi; and a managed pine forest in Hidalgo. Sites are maintained with an individual researcher's funds from Mexican government agencies (e.g., CONACYT) and international collaborations, but no coordinated funding exists for a long-term program.

  17. Deadwood biomass: an underestimated carbon stock in degraded tropical forests?

    Science.gov (United States)

    Pfeifer, Marion; Lefebvre, Veronique; Turner, Edgar; Cusack, Jeremy; Khoo, MinSheng; Chey, Vun K.; Peni, Maria; Ewers, Robert M.

    2015-04-01

    Despite a large increase in the area of selectively logged tropical forest worldwide, the carbon stored in deadwood across a tropical forest degradation gradient at the landscape scale remains poorly documented. Many carbon stock studies have either focused exclusively on live standing biomass or have been carried out in primary forests that are unaffected by logging, despite the fact that coarse woody debris (deadwood with ≥10 cm diameter) can contain significant portions of a forest’s carbon stock. We used a field-based assessment to quantify how the relative contribution of deadwood to total above-ground carbon stock changes across a disturbance gradient, from unlogged old-growth forest to severely degraded twice-logged forest, to oil palm plantation. We measured in 193 vegetation plots (25 × 25 m), equating to a survey area of >12 ha of tropical humid forest located within the Stability of Altered Forest Ecosystems Project area, in Sabah, Malaysia. Our results indicate that significant amounts of carbon are stored in deadwood across forest stands. Live tree carbon storage decreased exponentially with increasing forest degradation 7-10 years after logging while deadwood accounted for >50% of above-ground carbon stocks in salvage-logged forest stands, more than twice the proportion commonly assumed in the literature. This carbon will be released as decomposition proceeds. Given the high rates of deforestation and degradation presently occurring in Southeast Asia, our findings have important implications for the calculation of current carbon stocks and sources as a result of human-modification of tropical forests. Assuming similar patterns are prevalent throughout the tropics, our data may indicate a significant global challenge to calculating global carbon fluxes, as selectively-logged forests now represent more than one third of all standing tropical humid forests worldwide.

  18. Accounting for Risk in Valuing Forest Carbon Offsets

    Science.gov (United States)

    Hurteau, M. D.; Hungate, B. A.; Koch, G. W.

    2008-12-01

    Forests can sequester carbon dioxide, thereby reducing atmospheric concentrations and slowing global warming. U.S. Forest carbon stocks have increased as a result of regrowth following land abandonment and in-growth due to fire suppression. Increasing carbon density and reducing emissions from disturbances (fire, pest outbreaks) are two potential strategies for using forests to slow the rise of atmospheric CO2. The recent increase in frequency of large and severe fires due to past fire suppression and ongoing climate change represents risk in forest carbon offset investment. Under current carbon accounting mechanisms, all forest carbon offset projects are equivalent provided they meet additionality and permanence standards. Risk of loss from disturbance is not incorporated into quantifying permanence, even though some forests are at greater risk than others. We used the fire regime condition class (FRCC) departure index and mean fire return interval (mFRI) data products developed for the LANDFIRE project to discount the market value of forest carbon as a function of the risk of loss due to wildfire. Based on our risk assessment valuation method, the value of carbon varies depending on forest type and condition. For example, a unit carbon in fire-prone ponderosa pine forests of the Southwestern U.S. is worth only 24% of that in redwood forest. FRCC departure can be altered, making this equation robust to management actions and allowing for site specific quantification of the carbon market value of a management action. Substitution of FRCC and mFRI with the appropriate metrics would allow application of this approach to discounting market value of forest carbon due to risks of other disturbances such as forest pest outbreaks.

  19. Evaluating carbon fluxes of global forest ecosystems by using an individual tree-based model FORCCHN.

    Science.gov (United States)

    Ma, Jianyong; Shugart, Herman H; Yan, Xiaodong; Cao, Cougui; Wu, Shuang; Fang, Jing

    2017-02-14

    The carbon budget of forest ecosystems, an important component of the terrestrial carbon cycle, needs to be accurately quantified and predicted by ecological models. As a preamble to apply the model to estimate global carbon uptake by forest ecosystems, we used the CO2 flux measurements from 37 forest eddy-covariance sites to examine the individual tree-based FORCCHN model's performance globally. In these initial tests, the FORCCHN model simulated gross primary production (GPP), ecosystem respiration (ER) and net ecosystem production (NEP) with correlations of 0.72, 0.70 and 0.53, respectively, across all forest biomes. The model underestimated GPP and slightly overestimated ER across most of the eddy-covariance sites. An underestimation of NEP arose primarily from the lower GPP estimates. Model performance was better in capturing both the temporal changes and magnitude of carbon fluxes in deciduous broadleaf forest than in evergreen broadleaf forest, and it performed less well for sites in Mediterranean climate. We then applied the model to estimate the carbon fluxes of forest ecosystems on global scale over 1982-2011. This application of FORCCHN gave a total GPP of 59.41±5.67 and an ER of 57.21±5.32PgCyr(-1) for global forest ecosystems during 1982-2011. The forest ecosystems over this same period contributed a large carbon storage, with total NEP being 2.20±0.64PgCyr(-1). These values are comparable to and reinforce estimates reported in other studies. This analysis highlights individual tree-based model FORCCHN could be used to evaluate carbon fluxes of forest ecosystems on global scale.

  20. Understanding Oscillations of the Geological Carbon Cycle

    Science.gov (United States)

    Bachan, A.; Payne, J.; Saltzman, M.; Thomas, E.; Kump, L. R.

    2015-12-01

    The geological cycling of carbon ties together the sedimentary reservoirs with Earth's biosphere and climate. Perturbations to this coupled system are recorded in the carbon isotopic composition of marine limestones (δ13Ccarb). In the past decade numerous intervals of large-amplitude oscillations in δ13Ccarbhave been identified, with a variety of explanations proposed for individual events. Yet, when data spanning the past ~1 Ga are viewed as a whole, it is clear that large-scale oscillations are a common feature of the carbon isotopic record. The ubiquity of oscillations suggests that they may share a single origin rather than having many disparate causes. Here we present a simple two-box model of the geological carbon cycle exhibiting such oscillations: the Carbon-Cycle Oscillator. Analogous to a damped mass-spring system, the burial fluxes of carbonate and phosphate in the model act like friction, whereas P supply and Corg burial act like the restoring force of the spring. When the sensitivities of P supply and Corg burial to the sizes of the C and P reservoirs, respectively, increase above a critical threshold, the model exhibits oscillations upon perturbation. We suggest that intervals with large oscillations in bulk ocean-atmosphere δ13C are characterized by a greater sensitivity of the C:P burial-ratio and ALK:P weathering-ratio to the state of the ocean-atmosphere carbon pool. In addition, moderating of the slope of that dependence in general can account for the observed decrease in the amplitude of oscillations over the past billion years. We hypothesize that factors with a unidirectional trajectory during Earth history (e.g. increased oxygenation of the deep ocean, and evolution of pelagic calcifiers) led to a decrease in the Earth System's gain and increase in its resilience over geologic time, even in the face of continuing perturbations from the solid Earth and extraterrestrial realms.

  1. Soil Carbon and Nitrogen Cycle Modeling

    Science.gov (United States)

    Woo, D.; Chaoka, S.; Kumar, P.; Quijano, J. C.

    2012-12-01

    Second generation bioenergy crops, such as miscanthus (Miscantus × giganteus) and switchgrass (Panicum virgatum), are regarded as clean energy sources, and are an attractive option to mitigate the human-induced climate change. However, the global climate change and the expansion of perennial grass bioenergy crops have the power to alter the biogeochemical cycles in soil, especially, soil carbon storages, over long time scales. In order to develop a predictive understanding, this study develops a coupled hydrological-soil nutrient model to simulate soil carbon responses under different climate scenarios such as: (i) current weather condition, (ii) decreased precipitation by -15%, and (iii) increased temperature up to +3C for four different crops, namely miscanthus, switchgrass, maize, and natural prairie. We use Precision Agricultural Landscape Modeling System (PALMS), version 5.4.0, to capture biophysical and hydrological components coupled with a multilayer carbon and ¬nitrogen cycle model. We apply the model at daily time scale to the Energy Biosciences Institute study site, located in the University of Illinois Research Farms, in Urbana, Illinois. The atmospheric forcing used to run the model was generated stochastically from parameters obtained using available data recorded in Bondville Ameriflux Site. The model simulations are validated with observations of drainage and nitrate and ammonium concentrations recorded in drain tiles during 2011. The results of this study show (1) total soil carbon storage of miscanthus accumulates most noticeably due to the significant amount of aboveground plant carbon, and a relatively high carbon to nitrogen ratio and lignin content, which reduce the litter decomposition rate. Also, (2) the decreased precipitation contributes to the enhancement of total soil carbon storage and soil nitrogen concentration because of the reduced microbial biomass pool. However, (3) an opposite effect on the cycle is introduced by the increased

  2. THE DISTRIBUTION OF ORGANIC CARBON IN MAJOR COMPONENTS OF FORESTS LOCATED IN FIVE LIFE ZONES OF VENEZUELA

    Science.gov (United States)

    One of the major uncertainties concerning the role of tropical forests in the global carbon cycle is the lack of adequate data on the carbon content of all their components. The goal of this study was to contribute to filling this data gap by estimating the quantity of carbon in ...

  3. The decadal state of the terrestrial carbon cycle

    NARCIS (Netherlands)

    Velde, van der I.R.; Bloom, J.; Exbrayat, J.; Feng, L.; Williams, M.

    2015-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  4. The decadal state of the terrestrial carbon cycle

    NARCIS (Netherlands)

    Velde, van der I.R.; Bloom, J.; Exbrayat, J.; Feng, L.; Williams, M.

    2016-01-01

    The terrestrial carbon cycle is currently the least constrained component of the global carbon budget. Large uncertainties stem from a poor understanding of plant carbon allocation, stocks, residence times, and carbon use efficiency. Imposing observational constraints on the terrestrial carbon cycle

  5. Cycling of black carbon in the ocean

    Science.gov (United States)

    Coppola, Alysha I.; Druffel, Ellen R. M.

    2016-05-01

    Black carbon (BC) is a by-product of combustion from wildfires and fossil fuels and is a slow-cycling component of the carbon cycle. Whether BC accumulates and ages on millennial time scales in the world oceans has remained unknown. Here we quantified dissolved BC (DBC) in marine dissolved organic carbon isolated by solid phase extraction at several sites in the world ocean. We find that DBC in the Atlantic, Pacific, and Arctic oceans ranges from 1.4 to 2.6 μM in the surface and is 1.2 ± 0.1 μM in the deep Atlantic. The average 14C age of surface DBC is 4800 ± 620 14C years and much older in a deep water sample (23,000 ± 3000 14C years). The range of DBC structures and 14C ages indicates that DBC is not homogeneous in the ocean. We show that there are at least two distinct pools of marine DBC, a younger pool that cycles on centennial time scales and an ancient pool that cycles on >105 year time scales.

  6. Carbon consequences of forest disturbance and recovery across the conterminous United States

    Science.gov (United States)

    Williams, Christopher A.; Collatz, G. James; Masek, Jeffrey; Goward, Samuel N.

    2012-03-01

    Forests of North America are thought to constitute a significant long-term sink for atmospheric carbon. The United States Forest Service Forest Inventory and Analysis (FIA) program has developed a large database of stock changes derived from consecutive estimates of growing stock volume in the U.S. These data reveal a large and relatively stable increase in forest carbon stocks over the last two decades or more. The mechanisms underlying this national increase in forest stocks may include recovery of forests from past disturbances, net increases in forest area, and growth enhancement driven by climate or fertilization by CO2and Nitrogen. Here we estimate the forest recovery component of the observed stock changes using FIA data on the age structure of U.S. forests and carbon stocks as a function of age. The latter are used to parameterize forest disturbance and recovery processes in a carbon cycle model. We then apply resulting disturbance/recovery dynamics to landscapes and regions based on the forest age distributions. The analysis centers on 28 representative climate settings spread about forested regions of the conterminous U.S. We estimate carbon fluxes for each region and propagate uncertainties in calibration data through to the predicted fluxes. The largest recovery-driven carbon sinks are found in the South Central, Pacific Northwest, and Pacific Southwest regions, with spatially averaged net ecosystem productivity (NEP) of about 100 g C m-2 a-1 driven by forest age structure. Carbon sinks from recovery in the Northeast and Northern Lakes States remain moderate to large owing to the legacy of historical clearing and relatively low modern disturbance rates from harvest and fire. At the continental scale, we find a conterminous U.S. forest NEP of only 0.16 Pg C a-1 from age structure in 2005, or only 0.047 Pg C a-1 of forest stock change after accounting for fire emissions and harvest transfers. Recent estimates of NEP derived from inventory stock change

  7. Simultaneous reproduction of global carbon exchange and storage of terrestrial forest ecosystems

    Science.gov (United States)

    Kondo, M.; Ichii, K.

    2012-12-01

    Understanding the mechanism of the terrestrial carbon cycle is essential for assessing the impact of climate change. Quantification of both carbon exchange and storage is the key to the understanding, but it often associates with difficulties due to complex entanglement of environmental and physiological factors. Terrestrial ecosystem models have been the major tools to assess the terrestrial carbon budget for decades. Because of its strong association with climate change, carbon exchange has been more rigorously investigated by the terrestrial biosphere modeling community. Seeming success of model based assessment of carbon budge often accompanies with the ill effect, substantial misrepresentation of storage. In practice, a number of model based analyses have paid attention solely on terrestrial carbon fluxes and often neglected carbon storage such as forest biomass. Thus, resulting model parameters are inevitably oriented to carbon fluxes. This approach is insufficient to fully reduce uncertainties about future terrestrial carbon cycles and climate change because it does not take into account the role of biomass, which is equivalently important as carbon fluxes in the system of carbon cycle. To overcome this issue, a robust methodology for improving the global assessment of both carbon budget and storage is needed. One potentially effective approach to identify a suitable balance of carbon allocation proportions for each individual ecosystem. Carbon allocations can influence the plant growth by controlling the amount of investment acquired from photosynthesis, as well as carbon fluxes by controlling the carbon content of leaves and litter, both are active media for photosynthesis and decomposition. Considering those aspects, there may exist the suitable balance of allocation proportions enabling the simultaneous reproduction of carbon budget and storage. The present study explored the existence of such suitable balances of allocation proportions, and examines the

  8. Carbon cycle uncertainty in the Alaskan Arctic

    Directory of Open Access Journals (Sweden)

    J. B. Fisher

    2014-02-01

    Full Text Available Climate change is leading to a disproportionately large warming in the high northern latitudes, but the magnitude and sign of the future carbon balance of the Arctic are highly uncertain. Using 40 terrestrial biosphere models for Alaska, we provide a baseline of terrestrial carbon cycle structural and parametric uncertainty, defined as the multi-model standard deviation (σ against the mean (x for each quantity. Mean annual uncertainty (σ/x was largest for net ecosystem exchange (NEE (−0.01± 0.19 kg C m−2 yr−1, then net primary production (NPP (0.14 ± 0.33 kg C m−2 yr−1, autotrophic respiration (Ra (0.09 ± 0.20 kg C m−2 yr−1, gross primary production (GPP (0.22 ± 0.50 kg C m−2 yr−1, ecosystem respiration (Re (0.23 ± 0.38 kg C m−2 yr−1, CH4 flux (2.52 ± 4.02 g CH4 m−2 yr−1, heterotrophic respiration (Rh (0.14 ± 0.20 kg C m−2 yr−1, and soil carbon (14.0± 9.2 kg C m−2. The spatial patterns in regional carbon stocks and fluxes varied widely with some models showing NEE for Alaska as a strong carbon sink, others as a strong carbon source, while still others as carbon neutral. Additionally, a feedback (i.e., sensitivity analysis was conducted of 20th century NEE to CO2 fertilization (β and climate (γ, which showed that uncertainty in γ was 2x larger than that of β, with neither indicating that the Alaskan Arctic is shifting towards a certain net carbon sink or source. Finally, AmeriFlux data are used at two sites in the Alaskan Arctic to evaluate the regional patterns; observed seasonal NEE was captured within multi-model uncertainty. This assessment of carbon cycle uncertainties may be used as a baseline for the improvement of experimental and modeling activities, as well as a reference for future trajectories in carbon cycling with climate change in the Alaskan Arctic.

  9. Drought stress and carbon uptake in an Amazon forest measured with spaceborne imaging spectroscopy.

    Science.gov (United States)

    Asner, Gregory P; Nepstad, Daniel; Cardinot, Gina; Ray, David

    2004-04-20

    Amazônia contains vast stores of carbon in high-diversity ecosystems, yet this region undergoes major changes in precipitation affecting land use, carbon dynamics, and climate. The extent and structural complexity of Amazon forests impedes ground studies of ecosystem functions such as net primary production (NPP), water cycling, and carbon sequestration. Traditional modeling and remote-sensing approaches are not well suited to tropical forest studies, because (i) biophysical mechanisms determining drought effects on canopy water and carbon dynamics are poorly known, and (ii) remote-sensing metrics of canopy greenness may be insensitive to small changes in leaf area accompanying drought. New spaceborne imaging spectroscopy may detect drought stress in tropical forests, helping to monitor forest physiology and constrain carbon models. We combined a forest drought experiment in Amazônia with spaceborne imaging spectrometer measurements of this area. With field data on rainfall, soil water, and leaf and canopy responses, we tested whether spaceborne hyperspectral observations quantify differences in canopy water and NPP resulting from drought stress. We found that hyperspectral metrics of canopy water content and light-use efficiency are highly sensitive to drought. Using these observations, forest NPP was estimated with greater sensitivity to drought conditions than with traditional combinations of modeling, remote-sensing, and field measurements. Spaceborne imaging spectroscopy will increase the accuracy of ecological studies in humid tropical forests.

  10. Forest Carbon Offsets Revisited: Shedding Light on Darkwoods

    NARCIS (Netherlands)

    Kooten, van G.C.; Bogle, T.; Vries, de F.P.

    2015-01-01

    This paper investigates the viability of carbon offset credits created through forest conservation and preservation. A detailed forest management model based on a case study of a forest estate in southeastern British Columbia, owned by The Nature Conservancy of Canada (NCC) is used to demonstrate th

  11. A framework for identifying carbon hotspots and forest management drivers

    Science.gov (United States)

    Nilesh Timilsina; Francisco J. Escobedo; Wendell P. Cropper; Amr Abd-Elrahman; Thomas Brandeis; Sonia Delphin; Samuel Lambert

    2013-01-01

    Spatial analyses of ecosystem system services that are directly relevant to both forest management decision making and conservation in the subtropics are rare. Also, frameworks that identify and map carbon stocks and corresponding forest management drivers using available regional, national, and international-level forest inventory datasets could provide insights into...

  12. The new forest carbon accounting framework for the United States

    Science.gov (United States)

    Grant M. Domke; John W. Coulston; Christopher W. Woodall

    2015-01-01

    The forest carbon accounting system used in recent National Greenhouse Gas Inventories (NGHGI) was developed more than a decade ago when the USDA Forest Service, Forest Inventory and Analysis annual inventory system was in its infancy and contemporary questions regarding the terrestrial sink (e.g., attribution) did not exist. The time has come to develop a new...

  13. Carbon Legacy of Forest Degradation Foregone: can Europe's Forests Contribute to Deep Decarbonization?

    Science.gov (United States)

    Kauppi, P.; Nabuurs, G. J.

    2016-12-01

    Contemporary European forests, comprising 161 Mha, play a large role in mitigation of the EU carbon emissions. These intensively managed forests, roughly compensate 10% of EU emissions in forest carbon, in synchrony with the harvest for lumber, fibre and bioenergy, . But this has not always been the case; European forests are recovering since roughly 1850 from thousands of years of human induced degradation. The impact of more recent management is profound and has stimulated a worldwide unique and unprecedented recovery of this forest biome, partly in terms of area, but mainly in forest density that is, biomass per hectare increases. Based on what we know of the recent historic development, can these forests further contribute to deep decarbonization and how? We outline historic development of European forests since roughly 0 AD. We sketch evidence on degradation and deforestation, and on the impact of forest management on restoring the forest growth thus feeding on biomass recovery. We estimate the historical trajectory of the recovery from forest degradation. We discuss the future pathways of European forest resources, and the prospects for the European-model recovery to occur in degraded forests of the other continents. Based on this evidence from the past, we outline what Climate Smart Forestry could mean in the European circumstances aiming to further strengthen this role of European forests. Big scientific challenges remain to understand and project the future development of these forests under climate change and natural disturbances closely entangled with forest management and new demands of industry in the bio-economy.

  14. The Coupled Nature of C and N Cycles in Forest Ecosystems: Evidence, Implications and Uncertainties

    Science.gov (United States)

    Ollinger, S. V.; Aber, J. D.; Sievering, H.

    2001-12-01

    Cycles of carbon and nitrogen in forest ecosystems are mutually and interactively linked through a shared set of biological processes. A large number of field studies across diverse biomes have documented strong and generalizable relationships between foliar nitrogen concentrations and rates of net photosynthesis. This trend reflects the fact that the majority of N in plant canopies is found in the proteins responsible for CO2 capture (e.g. rubisco). In soils, the accumulation and availability of nitrogen is, in turn, affected by the quality and N content of litter inputs from vegetation. Taken together, these patterns reflect the broadly-coupled nature of terrestrial C and N cycles and suggest that human alteration of any aspect of one cycle can have important implications for the other. Nevertheless, the exact nature of C-N interactions in natural ecosystems can depend on a variety of factors including historical disturbance patterns, the effects of carbon quality on decomposition and N turnover, and the resulting differences in plant-soil feedbacks among species and functional groups. All of these factors greatly complicate efforts to characterize present-day patterns of C and N fluxes across real forested landscapes. Further, human-induced increases in atmospheric CO2 and N deposition hold the potential for either tightening the linkages between C and N cycles, or causing them to become uncoupled. This presentation will build on basic concepts to address several broad questions regarding C-N interactions in forests, both as they occur naturally and as they may be affected by elevated CO2 or N deposition: 1) What evidence is available from the field to demonstrate the coupled nature of C-N cycles in native forest ecosystems? 2) How are C-N interactions in forests influenced by the growth and allocation strategies of different species and/or functional groups? 3) To what degree are current C and N cycles reflected in the chemistry of forest foliage, and 4) Is

  15. A Model-Based Analysis of Nitrogen Deposition: Effects on Forest Carbon Sequestration

    Science.gov (United States)

    Dezi, S.; Medlyn, B. E.; Tonon, G.; Magnani, F.

    2009-04-01

    Over the last 150 years nitrogen deposition has increased, especially in the northern hemisphere, mainly due to the use of fossil fuels, deforestation and agricultural practices. Although the impact of this increase on the terrestrial carbon cycle is still uncertain, it is likely that this large perturbation of the global nitrogen cycle will have important effects on carbon cycling, particularly via impacts on forest carbon storage. In the present work we investigated qualitatively the overall response of forest carbon sequestration to nitrogen deposition, and the relative importance of different mechanisms that bring about this response. For this purpose we used the G'DAY forest carbon-nitrogen cycling model (Comins and McMurtrie 1993), introducing some new assumptions which focus on the effect of nitrogen deposition. Specifically the new assumptions are: (i) foliar litterfall and specific leaf area (SLA) are functions of leaf nitrogen concentration; (ii) belowground C allocation is a function of net primary production (NPP); (iii) forest canopies can directly take up nitrogen; (iv) management of forests occurs; (v) leaching occurs only for nitrate nitrogen. We investigated the effect of each assumption on net ecosystem production (NEP), with a step increase in nitrogen deposition from a steady state of 0.4 gN m-2 yr-1 to 2 gN m-2 yr-1, and then running the old and new model versions for different nitrogen deposition levels. Our analysis showed that nitrogen deposition can have a large effect on forest carbon storage at ecosystem level. In particular the effect of the assumptions (ii), (iii) and (iv) seem to be of greater importance, giving rise to a markedly higher level of forest carbon sequestration than in their absence. On the contrary assumptions (i) and (v) seem not to have any particular effect on the NEP simulated. Finally, running the models for different levels of nitrogen deposition showed that estimating forest carbon exchange without taking into

  16. Participatory Forest Carbon Assessment and REDD+: Learning from Tanzania

    Directory of Open Access Journals (Sweden)

    Kusaga Mukama

    2012-01-01

    Full Text Available Research initiatives and practical experiences have demonstrated that forest-related data collected by local communities can play an essential role in the development of national REDD+ programs and its' measurement, reporting, verification (MRV systems. In Tanzania, the national REDD+ Strategy aims to reward local communities participating in forest management under Participatory Forest Management (PFM. Accessing carbon finances requires among other things, accurate measurements of carbon stock changes through conventional forest inventories, something which is rarely done in PFM forests due to its high cost and limited resources. The main objective of this paper is to discuss experiences of Participatory Forest Carbon Assessment (PFCA in Tanzania. The study revealed that villagers who participated in PFCA were able to perform most steps for carbon assessment in the field. A key challenge in future is how to finance PFCA and ensure the technical capacity at local level.

  17. Aged forests could still act as carbon sinks

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Old-growth forests are traditionally negligible as carbon sinks, but CAS scientists recently reported that the buildup of atmospheric carbon in the top-soils of 400-year-old forests in southern China has increased at an unexpectedly high rate up to nearly 68% from 1979 to 2003.

  18. Carbon, nitrogen cycling and land cover changes during regrowth in African dry tropical forests: integrating perspectives from field and satellite data across a chronosequence in the Miombo Woodlands of western Tanzania

    Science.gov (United States)

    Mayes, M. T.; Melillo, J. M.; Mustard, J. F.; Neill, C.; Nyadzi, G.

    2015-12-01

    Seasonally dry tropical forests in Africa (SDTFs), such as forests in Miombo Woodlands, are experiencing high rates of deforestation, degradation and regrowth. Increasing proportions of forest are disturbed or composed of young regrowth stands (soil mineral N availability with regrowth; (2) How does N demand for tree leaf production compare to indicators of available mineral N in surface soils from young to mature forest sites; (3) How does canopy structure vary with regrowth and disturbance and scale to Landsat-style satellite data? We established a chronosequence of 18 sites with ages 3 to >40 years since abandonment. At each, we inventoried trees to quantify aboveground tree C stocks, sampled soils to 100 cm to measure C, total and mineral N (NH4+, NO3-), and surveyed canopy cover with point-line transects, spherical densiometer and photometric leaf area measures. We also conducted soil incubations to determine nitrogen mineralization potentials. Tree C stocks ranged from 0.4 ± 0.1 Mg C ha-1 for 3-4 year sites to 27.2 ± 5.2 Mg C ha-1 for 30-40 year sites, and were 44.5 ± 7.4 Mg C ha-1 for mature forest sites. Rates of aboveground tree C stock changes (0.78 - 0.89 Mg C ha-1 yr-1) were comparable to the few published for Miombo forests. However, tree C stocks at 10 - 24 year sites (5.2 ± 1.1 Mg C ha -1) were much lower than those reported in comparable studies. Only sites > 30-40 years had C stocks approaching mature forests. Further analyses will compare N dynamics from leaves and soil across the chronosequence, and relate them to the trends in tree C stocks. We use ground and canopy cover data to test remote sensing characterizations of land cover across disturbed and regrowth sites. Such scaling relationships will allow us to improve remote sensing characterization of land cover in African SDTFs and develop landscape-scale estimates of how forest cover changes affect C, N and water cycling regionally.

  19. Perspective of Chinese Forest Carbon Absorption Trade Based on Low-Carbon Economy

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The paper analyzes the basis of forest carbon trade including the feasibility of carbon absorption trade,main body,platform and standard.The purposes of capital of carbon absorption trade is introduced.Caron absorption trade capital can be used to resettle ecological migrants,absorb employment,build forest and increase fund,increase local income,enhance forest science and technology development and launch environmental proportion.The perspective of developing forest carbon absorption trade is pointed out and the practical problems of developing forest carbon trade need to be solved.For example,the property problem of forest resources,value calculation problem of forest resources and sustainable development of forest.

  20. Effects of multiple interacting disturbances and salvage logging on forest carbon stocks

    Science.gov (United States)

    Bradford, J.B.; Fraver, S.; Milo, A.M.; D'Amato, A.W.; Palik, B.; Shinneman, D.J.

    2012-01-01

    Climate change is anticipated to increase the frequency of disturbances, potentially impacting carbon stocks in terrestrial ecosystems. However, little is known about the implications of either multiple disturbances or post-disturbance forest management activities on ecosystem carbon stocks. This study quantified how forest carbon stocks responded to stand-replacing blowdown and wildfire, both individually and in combination with and without post-disturbance salvage operations, in a sub-boreal jack pine ecosystem. Individually, blowdown or fire caused similar decreases in live carbon and total ecosystem carbon. However, whereas blowdown increased carbon in down woody material and forest floor, fire increased carbon in standing snags, a difference that may have consequences for long-term carbon cycling patterns. Fire after the blowdown caused substantial additional reduction in ecosystem carbon stocks, suggesting that potential increases in multiple disturbance events may represent a challenge for sustaining ecosystem carbon stocks. Salvage logging, as examined here, decreased carbon stored in snags and down woody material but had no significant effect on total ecosystem carbon stocks.

  1. Participatory Forest Carbon Assessment and REDD+: Learning from Tanzania

    OpenAIRE

    Kusaga Mukama; Irmeli Mustalahti; Eliakimu Zahabu

    2012-01-01

    Research initiatives and practical experiences have demonstrated that forest-related data collected by local communities can play an essential role in the development of national REDD+ programs and its' measurement, reporting, verification (MRV) systems. In Tanzania, the national REDD+ Strategy aims to reward local communities participating in forest management under Participatory Forest Management (PFM). Accessing carbon finances requires among other things, accurate measurements of carbon s...

  2. Edaphic controls on ecosystem-level carbon allocation in two contrasting Amazon forests

    Science.gov (United States)

    Jiménez, Eliana M.; Peñuela-Mora, María. Cristina; Sierra, Carlos A.; Lloyd, Jon; Phillips, Oliver L.; Moreno, Flavio H.; Navarrete, Diego; Prieto, Adriana; Rudas, Agustín.; Álvarez, Esteban; Quesada, Carlos A.; Grande-Ortíz, Maria Angeles; García-Abril, Antonio; Patiño, Sandra

    2014-09-01

    Studies of carbon allocation in forests provide essential information for understanding spatial and temporal differences in carbon cycling that can inform models and predict possible responses to changes in climate. Amazon forests play a particularly significant role in the global carbon balance, but there are still large uncertainties regarding abiotic controls on the rates of net primary production (NPP) and the allocation of photosynthetic products to different ecosystem components. We evaluated three different aspects of stand-level carbon allocation (biomass, NPP, and its partitioning) in two amazon forests on different soils (nutrient-rich clay soils versus nutrient-poor sandy soils) but otherwise growing under similar conditions. We found differences in carbon allocation patterns between these two forests, showing that the forest on clay soil had a higher aboveground and total biomass as well as a higher aboveground NPP than the sandy forest. However, differences between the two forest types in terms of total NPP were smaller, as a consequence of different patterns in the carbon allocation of aboveground and belowground components. The proportional allocation of NPP to new foliage was relatively similar between them. Our results of aboveground biomass increments and fine-root production suggest a possible trade-off between carbon allocation to fine roots versus aboveground compartments, as opposed to the most commonly assumed trade-off between total aboveground and belowground production. Despite these differences among forests in terms of carbon allocation, the leaf area index showed only small differences, suggesting that this index is more indicative of total NPP than its aboveground or belowground components.

  3. Consequences of climate change for biogeochemical cycling in forests of northeastern North America

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, J.L.; Rustad, L.E. [United States Forest Service, Durham, NH (United States). Northern Research Station; Boyer, E.W. [Pennsylvania State Univ., University Park, PA (United States). School of Forest Resources; Christopher, S.F. [Buffalo State College, Buffalo, NY (United States). Great Lakes Center; Driscoll, C.T.; Kiekbusch, J. [Syracuse Univ., Syracuse, NY (United States). Dept. of Civil and Environmental Engineering; Fernandex, I.J. [Maine Univ., Orono, ME (United States). Dept. of Plant, Soil and Environmental Sciences; Groffman, P.M. [Cary Inst. of Ecosystem Studies, Millbrook, NY (United States); Houle, D. [Quebec Ministere des ressources naturelles et de la Faune, Ste Foy, PQ (Canada). Direction de la recherche forestiere; Ouranos, Montreal, PQ (Canada); Magill, A.H.; Ollinger, S.V. [New Hampshire Univ., Durham, NH (United States). Complex Systems Research Center; Mitchell, M.J. [State Univ. of New York, Syracuse, NY (United States). Dept. of Environmental and Forest Biology

    2009-02-15

    This paper examined the effects of climate change on the biogeochemical cycling of elements in forest ecosystems. The effects of climatic change on plant physiology, forest productivity and soil physical, chemical, and biological processes were evaluated. A case study used the quantitative biogeochemical PneT-BGC model to evaluate assumptions about the impacts of climatic change on a northern hardwood forest ecosystem. The study demonstrated an increase in net primary production as a result of a longer growing season, increases in nitrate leaching caused by increases in net mineralization and nitrification, and declines in mineral weathering as a result of soil moisture reductions. Changes in species composition, hydrology, and the length of the growing season will have have an impact on biogeochemical cycling. Further research is needed to investigate the influence of multiple simultaneous stressors; long-term carbon dioxide (CO{sub 2}) enrichment on vegetation; and changes in forest species composition. It was concluded that the impacts of extreme climatic events and other disturbances on forest ecosystems must also be evaluated. 174 refs., 2 figs.

  4. Buckling-driven delamination of carbon nanotube forests

    Science.gov (United States)

    Pour Shahid Saeed Abadi, Parisa; Hutchens, Shelby B.; Greer, Julia R.; Cola, Baratunde A.; Graham, Samuel

    2013-06-01

    We report buckling-driven delamination of carbon nanotube (CNT) forests from their growth substrates when subjected to compression. Macroscale compression experiments reveal local delamination at the CNT forest-substrate interface. Results of microscale flat punch indentations indicate that enhanced CNT interlocking at the top surface of the forest accomplished by application of a metal coating causes delamination of the forest from the growth substrate, a phenomenon not observed in indentation of as-grown CNT forests. We postulate that the post-buckling tensile stresses that develop at the base of the CNT forests serve as the driving force for delamination.

  5. Carbon, Climate, and Land-use in Ukraine: Forest Sector

    OpenAIRE

    Shvidenko, A.; P. Lakyda; Schepaschenko, D; R. Vasylyshyn; Machuk, Y.

    2014-01-01

    Stabilization of climate and maintenance of ecological stability over the planet within the paradigm of sustainable development underline the role of forests as one of the most effective and appropriate tools for climate change mitigation. This publication attempts to provide a system analysis of carbon budget of Ukrainian forests using internationally examined methods, as well as to analyze the impacts of the forests on climatic change within two potential scenarios of future forest manageme...

  6. National-scale estimates of forest root biomass carbon stocks and associated carbon fluxes in Canada

    Science.gov (United States)

    Smyth, C. E.; Kurz, W. A.; Neilson, E. T.; Stinson, G.

    2013-12-01

    forests play an important role in the global carbon cycle through carbon (C) storage and C exchange with the atmosphere. While estimates of aboveground biomass have been improving, little is known about belowground C storage in root biomass. Here we estimated the contribution of roots to the C budget of Canada's 2.3 × 106 km2 managed forests from 1990 to 2008 using the empirical modeling approach of the Carbon Budget Model of the Canadian Forest Sector (CBM-CFS3) driven by detailed forestry data sets from the National Forest C Monitoring, Accounting and Reporting System. The estimated average net primary production (NPP) during this period was 809 Tg C yr-1 (352 g C m2 yr-1) with root growth and replacement of turnover contributing 39.8 % of NPP. Average heterotrophic respiration (Rh) was 738 Tg C yr-1 (321 g C m-2 yr-1), which resulted in a net ecosystem production (NEP) value of 31 g C m-2 yr-1(71 Tg C yr-1), and on average only 8.7% of NPP remained in the system as NEP. Estimated average root C stocks were 2.38 Pg (1235 g C m-2), mostly in coarse roots (≥ 5 mm diameter), and had an average root to shoot percentage (belowground to aboveground biomass) of 25.6%. Detailed monitoring of C exchange between forests and the atmosphere and an improved understanding of the belowground processes and their response to environmental changes are needed to improve our understanding of the terrestrial C budget.

  7. Diversity and carbon storage across the tropical forest biome

    Science.gov (United States)

    Sullivan, Martin J. P.; Talbot, Joey; Lewis, Simon L.; Phillips, Oliver L.; Qie, Lan; Begne, Serge K.; Chave, Jerôme; Cuni-Sanchez, Aida; Hubau, Wannes; Lopez-Gonzalez, Gabriela; Miles, Lera; Monteagudo-Mendoza, Abel; Sonké, Bonaventure; Sunderland, Terry; Ter Steege, Hans; White, Lee J. T.; Affum-Baffoe, Kofi; Aiba, Shin-Ichiro; de Almeida, Everton Cristo; de Oliveira, Edmar Almeida; Alvarez-Loayza, Patricia; Dávila, Esteban Álvarez; Andrade, Ana; Aragão, Luiz E. O. C.; Ashton, Peter; Aymard C., Gerardo A.; Baker, Timothy R.; Balinga, Michael; Banin, Lindsay F.; Baraloto, Christopher; Bastin, Jean-Francois; Berry, Nicholas; Bogaert, Jan; Bonal, Damien; Bongers, Frans; Brienen, Roel; Camargo, José Luís C.; Cerón, Carlos; Moscoso, Victor Chama; Chezeaux, Eric; Clark, Connie J.; Pacheco, Álvaro Cogollo; Comiskey, James A.; Valverde, Fernando Cornejo; Coronado, Eurídice N. Honorio; Dargie, Greta; Davies, Stuart J.; de Canniere, Charles; Djuikouo K., Marie Noel; Doucet, Jean-Louis; Erwin, Terry L.; Espejo, Javier Silva; Ewango, Corneille E. N.; Fauset, Sophie; Feldpausch, Ted R.; Herrera, Rafael; Gilpin, Martin; Gloor, Emanuel; Hall, Jefferson S.; Harris, David J.; Hart, Terese B.; Kartawinata, Kuswata; Kho, Lip Khoon; Kitayama, Kanehiro; Laurance, Susan G. W.; Laurance, William F.; Leal, Miguel E.; Lovejoy, Thomas; Lovett, Jon C.; Lukasu, Faustin Mpanya; Makana, Jean-Remy; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S.; Junior, Ben Hur Marimon; Marshall, Andrew R.; Morandi, Paulo S.; Mukendi, John Tshibamba; Mukinzi, Jaques; Nilus, Reuben; Vargas, Percy Núñez; Camacho, Nadir C. Pallqui; Pardo, Guido; Peña-Claros, Marielos; Pétronelli, Pascal; Pickavance, Georgia C.; Poulsen, Axel Dalberg; Poulsen, John R.; Primack, Richard B.; Priyadi, Hari; Quesada, Carlos A.; Reitsma, Jan; Réjou-Méchain, Maxime; Restrepo, Zorayda; Rutishauser, Ervan; Salim, Kamariah Abu; Salomão, Rafael P.; Samsoedin, Ismayadi; Sheil, Douglas; Sierra, Rodrigo; Silveira, Marcos; Slik, J. W. Ferry; Steel, Lisa; Taedoumg, Hermann; Tan, Sylvester; Terborgh, John W.; Thomas, Sean C.; Toledo, Marisol; Umunay, Peter M.; Gamarra, Luis Valenzuela; Vieira, Ima Célia Guimarães; Vos, Vincent A.; Wang, Ophelia; Willcock, Simon; Zemagho, Lise

    2017-01-01

    Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity.

  8. Diversity and carbon storage across the tropical forest biome

    Science.gov (United States)

    Sullivan, Martin J. P.; Talbot, Joey; Lewis, Simon L.; Phillips, Oliver L.; Qie, Lan; Begne, Serge K.; Chave, Jerôme; Cuni-Sanchez, Aida; Hubau, Wannes; Lopez-Gonzalez, Gabriela; Miles, Lera; Monteagudo-Mendoza, Abel; Sonké, Bonaventure; Sunderland, Terry; ter Steege, Hans; White, Lee J. T.; Affum-Baffoe, Kofi; Aiba, Shin-ichiro; de Almeida, Everton Cristo; de Oliveira, Edmar Almeida; Alvarez-Loayza, Patricia; Dávila, Esteban Álvarez; Andrade, Ana; Aragão, Luiz E. O. C.; Ashton, Peter; Aymard C., Gerardo A.; Baker, Timothy R.; Balinga, Michael; Banin, Lindsay F.; Baraloto, Christopher; Bastin, Jean-Francois; Berry, Nicholas; Bogaert, Jan; Bonal, Damien; Bongers, Frans; Brienen, Roel; Camargo, José Luís C.; Cerón, Carlos; Moscoso, Victor Chama; Chezeaux, Eric; Clark, Connie J.; Pacheco, Álvaro Cogollo; Comiskey, James A.; Valverde, Fernando Cornejo; Coronado, Eurídice N. Honorio; Dargie, Greta; Davies, Stuart J.; De Canniere, Charles; Djuikouo K., Marie Noel; Doucet, Jean-Louis; Erwin, Terry L.; Espejo, Javier Silva; Ewango, Corneille E. N.; Fauset, Sophie; Feldpausch, Ted R.; Herrera, Rafael; Gilpin, Martin; Gloor, Emanuel; Hall, Jefferson S.; Harris, David J.; Hart, Terese B.; Kartawinata, Kuswata; Kho, Lip Khoon; Kitayama, Kanehiro; Laurance, Susan G. W.; Laurance, William F.; Leal, Miguel E.; Lovejoy, Thomas; Lovett, Jon C.; Lukasu, Faustin Mpanya; Makana, Jean-Remy; Malhi, Yadvinder; Maracahipes, Leandro; Marimon, Beatriz S.; Junior, Ben Hur Marimon; Marshall, Andrew R.; Morandi, Paulo S.; Mukendi, John Tshibamba; Mukinzi, Jaques; Nilus, Reuben; Vargas, Percy Núñez; Camacho, Nadir C. Pallqui; Pardo, Guido; Peña-Claros, Marielos; Pétronelli, Pascal; Pickavance, Georgia C.; Poulsen, Axel Dalberg; Poulsen, John R.; Primack, Richard B.; Priyadi, Hari; Quesada, Carlos A.; Reitsma, Jan; Réjou-Méchain, Maxime; Restrepo, Zorayda; Rutishauser, Ervan; Salim, Kamariah Abu; Salomão, Rafael P.; Samsoedin, Ismayadi; Sheil, Douglas; Sierra, Rodrigo; Silveira, Marcos; Slik, J. W. Ferry; Steel, Lisa; Taedoumg, Hermann; Tan, Sylvester; Terborgh, John W.; Thomas, Sean C.; Toledo, Marisol; Umunay, Peter M.; Gamarra, Luis Valenzuela; Vieira, Ima Célia Guimarães; Vos, Vincent A.; Wang, Ophelia; Willcock, Simon; Zemagho, Lise

    2017-01-01

    Tropical forests are global centres of biodiversity and carbon storage. Many tropical countries aspire to protect forest to fulfil biodiversity and climate mitigation policy targets, but the conservation strategies needed to achieve these two functions depend critically on the tropical forest tree diversity-carbon storage relationship. Assessing this relationship is challenging due to the scarcity of inventories where carbon stocks in aboveground biomass and species identifications have been simultaneously and robustly quantified. Here, we compile a unique pan-tropical dataset of 360 plots located in structurally intact old-growth closed-canopy forest, surveyed using standardised methods, allowing a multi-scale evaluation of diversity-carbon relationships in tropical forests. Diversity-carbon relationships among all plots at 1 ha scale across the tropics are absent, and within continents are either weak (Asia) or absent (Amazonia, Africa). A weak positive relationship is detectable within 1 ha plots, indicating that diversity effects in tropical forests may be scale dependent. The absence of clear diversity-carbon relationships at scales relevant to conservation planning means that carbon-centred conservation strategies will inevitably miss many high diversity ecosystems. As tropical forests can have any combination of tree diversity and carbon stocks both require explicit consideration when optimising policies to manage tropical carbon and biodiversity. PMID:28094794

  9. Terrestrial Carbon Losses from Mountaintop Coal Mining Offsets Regional Forest Carbon Sequestration in the 21ST Century

    Science.gov (United States)

    Acton, P. M.; Campbell, J. E.; Fox, J.

    2012-12-01

    Studies that quantify the spatial and temporal variability of carbon sources and sinks provide process-level information for predicting future levels of atmospheric carbon dioxide as well as verification of current emission agreements. Assessments of carbon sources and sinks for North America that compare top-down atmospheric constraints with bottom-up inventories find particularly large carbon sinks in the southeastern US. However, this southeastern US sink may be impacted by extreme land-use disturbance events due to mountaintop coal mining (MCM). Here we apply ecosystem modeling and field experiment data to quantify the potential impact of future mountaintop coal mining on the carbon budget of the southern Appalachian forest region. For projections based on historical mining rates and the continued regrowth of un-mined forests, we find that the southern Appalachian forests switch from a net carbon sink to a net carbon source by year 2025 to 2033 with a 30% to 35% loss is terrestrial carbon stocks relative to a scenario with no future mining of forest carbon by the year 2100. Alternatively, scenarios of forest sequestration due to the offsetting effects of CO2 fertilization and enhanced soil respiration result in a 15% to 24% loss in terrestrial carbon stocks by the year 2100 for mining scenarios relative to scenarios with no future mining. These results suggest that while stack emissions are the dominant life-cycle in coal-fired electricity, accounting for mountaintop coal mining in bottom-up inventories may be a critical land-use component of regional carbon budgets.

  10. Carbon reservoirs in temperate South American Nothofagus forests.

    Science.gov (United States)

    Böswald, Klaus; Lencinas, José D; Loguercio, Gabriel

    2002-01-08

    Humans are influencing the global carbon (C) cycle due to the combustion of fossil fuels and due to changes in land use management. These activities are fostering the manmade greenhouse effect and thus global climate change. Negative effects for life on earth are accounted for. Among others the international climate debate focused attention on forests and forestry, knowing about their considerable influence on global climate change. Whilst the global C budget is described fairly well, there is a lack of regional data describing the C reservoirs and flows in detail. This has to be constituted especially for forests in developing countries. This paper presents an investigation at regional scale of the C reservoirs in a South American forest ecosystem. The investigation puts emphasis on the area and stand volume estimation and the development of expansion and reduction factors. Vegetation types are classified and stratified, determining the corresponding areas and estimating the stand volume. Converting factors are developed to calculate C in branches and roots as a percentage of standing wood measured by inventories.

  11. The new forest carbon accounting framework for the United States

    Science.gov (United States)

    Domke, G. M.; Woodall, C. W.; Coulston, J.; Wear, D. N.; Healey, S. P.; Walters, B. F.

    2015-12-01

    The forest carbon accounting system used in recent National Greenhouse Gas Inventories (NGHGI) was developed more than a decade ago when the USDA Forest Service, Forest Inventory and Analysis annual inventory system was in its infancy and contemporary questions regarding the terrestrial sink (e.g., attribution) did not exist. The time has come to develop a new framework that can quickly address new questions, enables forest carbon analytics, and uses all the inventory information (e.g., disturbances and land use change) while having the flexibility to engage a wider breadth of stakeholders and partner agencies. The Forest Carbon Accounting Framework (FCAF) is comprised of a forest dynamics module and a land use dynamics module. Together these modules produce data-driven estimates of carbon stocks and stock changes in forest ecosystems that are sensitive to carbon sequestration, forest aging, and disturbance effects as well as carbon stock transfers associated with afforestation and deforestation. The new accounting system was used in the 2016 NGHGI report and research is currently underway to incorporate emerging non-live tree carbon pool data, remotely sensed information, and auxiliary data (e.g., climate information) into the FCAF.

  12. Carbon Stocks of Fine Woody Debris in Coppice Oak Forests at Different Development Stages

    Directory of Open Access Journals (Sweden)

    Ender Makineci

    2017-06-01

    Full Text Available Dead woody debris is a significant component of the carbon cycle in forest ecosystems. This study was conducted in coppice-originated oak forests to determine carbon stocks of dead woody debris in addition to carbon stocks of different ecosystem compartments from the same area and forests which were formerly elucidated. Weight and carbon stocks of woody debris were determined with recent samplings and compared among development stages (diameter at breast height (DBH, D1.3m, namely small-diameter forests (SDF = 0–8 cm, medium diameter forests (MDF = 8–20 cm, and large-diameter forests (LDF = 20–36 cm. Total woody debris was collected in samplings; as bilateral diameters of all woody debris parts were less than 10 cm, all woody parts were in the “fine woody debris (FWD” class. The carbon concentrations of FWD were about 48% for all stages. Mass (0.78–4.92 Mg·ha−1 and carbon stocks (0.38–2.39 Mg·ha−1 of FWD were significantly (p > 0.05 different among development stages. FWD carbon stocks were observed to have significant correlation with D1.3m, age, basal area, and carbon stocks of aboveground biomass (Spearman rank correlation coefficients; 0.757, 0.735, 0.709, and 0.694, respectively. The most important effects on carbon budgets of fine woody debris were determined to be coppice management and intensive utilization. Also, national forestry management, treatments of traditional former coppice, and conversion to high forest were emphasized as having substantial effects.

  13. Effects of Forest Management on Productivity and Carbon Sequestration:A Review and Hypothesis

    Science.gov (United States)

    Noormets, A.; Epron, D.; Domec, J. C.; Nouvellon, Y.; McNulty, S. G.; Chen, J.; Sun, G.; King, J. S.

    2015-12-01

    Forests hold more carbon than other terrestrial ecosystems and are seen as a key element in mitigating anthropogenic CO2 emissions. However, the viability of this assumption is not certain as our understanding of carbon dynamics in the soil is incomplete. Furthermore, as the world's forests are increasingly affected by human activities, and a growing fraction are actively managed, the differences in forest structure and function must be considered when projecting their role in global biogeochemical cycling. Our recent analysis found that managed forests were, on average, 50-years younger and had 2-fold lower C pools. The genetic selection process and cultivation practices (notably fertilization, competition control, and disturbance) also alter allocation patterns that, in combination with the structural differences mentioned above, may affect carbon inputs and outputs from the soil. As the role of managed forests on the landscape increases, distinguishing them from the natural forests becomes increasingly important. The current study demonstrates the importance of accounting for management effects, and proposes a simple technique for tracking soil balance. Our analysis of two global databases found that a large fraction of forest soils lose more C through heterotrophic respiration than they gain through non-harvest fresh litter inputs annually, and that the deficit is greater in managed than unmanaged forests.

  14. Differential sensitivity to climate change of C and N cycling processes across soil horizons in a northern hardwood forest

    Science.gov (United States)

    Jorge Durán; Jennifer L. Morse; Alexandra Rodríguez; John L. Campbell; Lynn M. Christenson; Charles T. Driscoll; Timothy J. Fahey; Melany C. Fisk; Myron J. Mitchell; Pamela H. Templer; Peter M. Groffman

    2017-01-01

    Climate of the northern hardwood forests of North America will become significantly warmer in the coming decades. Associated increases in soil temperature, decreases in water availability and changes in winter snow pack and soil frost are likely to affect soil carbon (C) and nitrogen (N) cycling. Most studies of the effects of climate change on soil function have...

  15. [Variation of forest vegetation carbon storage and carbon sequestration rate in Liaoning Province, Northeast China].

    Science.gov (United States)

    Zhen, Wei; Huang, Mei; Zhai, Yin-Li; Chen, Ke; Gong, Ya-Zhen

    2014-05-01

    The forest vegetation carbon stock and carbon sequestration rate in Liaoning Province, Northeast China, were predicted by using Canadian carbon balance model (CBM-CFS3) combining with the forest resource data. The future spatio-temporal distribution and trends of vegetation carbon storage, carbon density and carbon sequestration rate were projected, based on the two scenarios, i. e. with or without afforestation. The result suggested that the total forest vegetation carbon storage and carbon density in Liaoning Province in 2005 were 133.94 Tg and 25.08 t x hm(-2), respectively. The vegetation carbon storage in Quercus was the biggest, while in Robinia pseudoacacia was the least. Both Larix olgensis and broad-leaved forests had higher vegetation carbon densities than others, and the vegetation carbon densities of Pinus tabuliformis, Quercus and Robinia pseudoacacia were close to each other. The spatial distribution of forest vegetation carbon density in Liaoning Province showed a decrease trend from east to west. In the eastern forest area, the future increase of vegetation carbon density would be smaller than those in the northern forest area, because most of the forests in the former part were matured or over matured, while most of the forests in the later part were young. Under the scenario of no afforestation, the future increment of total forest vegetation carbon stock in Liaoning Province would increase gradually, and the total carbon sequestration rate would decrease, while they would both increase significantly under the afforestation scenario. Therefore, afforestation plays an important role in increasing vegetation carbon storage, carbon density and carbon sequestration rate.

  16. Carbon implications of forest restitution in post-socialist Romania

    Energy Technology Data Exchange (ETDEWEB)

    Olofsson, P; Woodcock, C E [Department of Geography and Environment, Boston University, 675 Commonwealth Avenue, Boston, MA 02215 (United States); Kuemmerle, T [Earth System Analysis, Potsdam Institute for Climate Impact Research (PIK), Telegraphenberg A62, D-14412 Potsdam (Germany); Griffiths, P; Knorn, J [Department of Geography, Humboldt-University Berlin, Unter den Linden 6, 10099 Berlin (Germany); Baccini, A; Houghton, R A [Woods Hole Research Center, 149 Woods Hole Road, Falmouth, MA 02540 (United States); Gancz, V [Forest Research and Management Institute (ICAS), Sos. Stefanesti 128, 077190 Voluntari, Bucharest (Romania); Blujdea, V [European Commission, Joint Research Centre, Institute for Environment and Sustainability, Climate Change and Air Quality Unit, Via Fermi, 21027 Ispra (Italy); Abrudan, I V, E-mail: olofsson@bu.edu [Faculty of Silviculture and Forest Engineering, Transylvania University of Brasov, Street Sirul Beethoven, nr. 1, Brasov (Romania)

    2011-10-15

    The collapse of socialism in 1989 triggered a phase of institutional restructuring in Central and Eastern Europe. Several countries chose to privatize forests or to return them to pre-socialist owners. Here, we assess the implications of forest restitution on the terrestrial carbon balance. New forest owners have strong incentives to immediately clearcut their forests, resulting in increased terrestrial emissions. On the other hand, logging generally decreased after 1989 and forests are expanding on unused or abandoned farmland, both of which may offset increased logging on restituted forests. We mapped changes in forest cover for the entire country of Romania using Landsat satellite images from 1990 to 2010. We use our satellite estimates, together with historic data on logging rates and changes in forest cover, to parameterize a carbon book-keeping model for estimating the terrestrial carbon flux (above and below ground) as a consequence of land use change and forest harvest. High logging rates during socialism resulted in substantial terrestrial carbon emissions and Romania was a net carbon source until the 1980s. After the collapse of the Soviet Union forest harvest rates decreased dramatically, but since restitution laws were implemented they have increased by 60% (from 15 122 {+-} 5397 ha y{sup -1} in 2000 to 23 884 {+-} 11 510 ha y{sup -1} in 2010), but still remain lower than prior to 1989. Romania currently remains a terrestrial carbon sink, offsetting 7.6% {+-} 2.5% of anthropogenic carbon emissions. A further increase in logging could result in net emissions from terrestrial ecosystems during the coming decades. However, forest expansion on degraded land and abandoned farmland offers great potential for carbon sequestration.

  17. Forest and wood products role in carbon sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Sampson, R.N.

    1997-12-31

    An evaluation of the use of U.S. forests and forest products for carbon emission mitigation is presented. The current role of forests in carbon sequestration is described in terms of regional differences and forest management techniques. The potential for increasing carbon storage by converting marginal crop and pasture land, increasing timberland growth, reducing wildfire losses, and changing timber harvest methods is examined. Post-harvest carbon flows, environmental impacts of wood products, biomass energy crops, and increased use of energy-conserving trees are reviewed for their potential in reducing or offsetting carbon emissions. It is estimated that these techniques could offset 20 to 40 percent of the carbon emitted annually in the U.S. 39 refs., 5 tabs.

  18. Carbon stocks and potential carbon storage in the mangrove forests of China.

    Science.gov (United States)

    Liu, Hongxiao; Ren, Hai; Hui, Dafeng; Wang, Wenqing; Liao, Baowen; Cao, Qingxian

    2014-01-15

    Mangrove forests provide important ecosystem services, and play important roles in terrestrial and oceanic carbon (C) cycling. Although the C stocks or storage in terrestrial ecosystems in China have been frequently assessed, the C stocks in mangrove forests have often been overlooked. In this study, we estimated the C stocks and the potential C stocks in China's mangrove forests by combining our own field data with data from the National Mangrove Resource Inventory Report and from other published literature. The results indicate that mangrove forests in China store about 6.91 ± 0.57 Tg C, of which 81.74% is in the top 1 m soil, 18.12% in the biomass of mangrove trees, and 0.08% in the ground layer (i.e. mangrove litter and seedlings). The potential C stocks are as high as 28.81 ± 4.16 Tg C. On average, mangrove forests in China contain 355.25 ± 82.19 Mg C ha(-1), which is consistent with the global average of mangrove C density at similar latitudes, but higher than the average C density in terrestrial forests in China. Our results suggest that C storage in mangroves can be increased by selecting high C-density species for afforestation and stand improvement, and even more by increasing the mangrove area. The information gained in this study will facilitate policy decisions concerning the restoration of mangrove forests in China.

  19. Future forest aboveground carbon dynamics in the central United States: the importance of forest demographic processes

    Science.gov (United States)

    Wenchi Jin; Hong S. He; Frank R. Thompson; Wen J. Wang; Jacob S. Fraser; Stephen R. Shifley; Brice B. Hanberry; William D. Dijak

    2017-01-01

    The Central Hardwood Forest (CHF) in the United States is currently a major carbon sink, there are uncertainties in how long the current carbon sink will persist and if the CHF will eventually become a carbon source. We used a multi-model ensemble to investigate aboveground carbon density of the CHF from 2010 to 2300 under current climate. Simulations were done using...

  20. Forest carbon accounting methods and the consequences of forest bioenergy for national greenhouse gas emissions inventories

    OpenAIRE

    McKechnie, Jon; Colombo, Steve; Heather L. MacLean

    2014-01-01

    While bioenergy plays a key role in strategies for increasing renewable energy deployment, studies assessing greenhouse gas (GHG) emissions from forest bioenergy systems have identified a potential trade-off of the system with forest carbon stocks. Of particular importance to national GHG inventories is how trade-offs between forest carbon stocks and bioenergy production are accounted for within the Agriculture, Forestry and Other Land Use (AFOLU) sector under current and future international...

  1. Accounting for risk in valuing forest carbon offsets

    Directory of Open Access Journals (Sweden)

    Koch George W

    2009-01-01

    Full Text Available Abstract Background Forests can sequester carbon dioxide, thereby reducing atmospheric concentrations and slowing global warming. In the U.S., forest carbon stocks have increased as a result of regrowth following land abandonment and in-growth due to fire suppression, and they currently sequester approximately 10% of annual US emissions. This ecosystem service is recognized in greenhouse gas protocols and cap-and-trade mechanisms, yet forest carbon is valued equally regardless of forest type, an approach that fails to account for risk of carbon loss from disturbance. Results Here we show that incorporating wildfire risk reduces the value of forest carbon depending on the location and condition of the forest. There is a general trend of decreasing risk-scaled forest carbon value moving from the northern toward the southern continental U.S. Conclusion Because disturbance is a major ecological factor influencing long-term carbon storage and is often sensitive to human management, carbon trading mechanisms should account for the reduction in value associated with disturbance risk.

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

    Science.gov (United States)

    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 (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.

  3. The fate of the tropical forest. Carbon or cattle?

    Energy Technology Data Exchange (ETDEWEB)

    Coomes, Oliver T. [Department of Geography, Burnside Hall Rm 705, McGill University, 805 Sherbrooke Street West, Montreal, PQ (Canada); Grimard, Franque [Department of Economics, Leacock Building, Rm. 433, McGill University, Sherbrooke St West, Montreal, PQ (Canada); Potvin, Catherin [Department of Biology, Stewart Biology Building, McGill University, 1205 Ave Docteur Penfield, Montreal, PQ (Canada); Sima, Philip [Philip Sima, School of Architecture, The University of Texas at Austin, 1 University Station B7500, Austin, Texas 78712-0222 (United States)

    2008-04-01

    Small-scale afforestation/reforestation projects under the Clean Development Mechanism (CDM) of the Kyoto Protocol will sequester atmospheric carbon and facilitate carbon trading but they face significant implementation challenges among the rural poor households and communities that are meant to adopt and benefit from them. Avoiding deforestation - a controversial carbon reduction option now under climate policy discussion - shows promise though for both forest conservation and poverty alleviation among indigenous forest peoples. (author)

  4. Estimating carbon stocks based on forest volume-age relationship

    Science.gov (United States)

    Hangnan, Y.; Lee, W.; Son, Y.; Kwak, D.; Nam, K.; Moonil, K.; Taesung, K.

    2012-12-01

    This research attempted to estimate potential change of forest carbon stocks between 2010 and 2110 in South Korea, using the forest cover map and National Forest Inventory (NFI) data. Allometric functions (logistic regression models) of volume-age relationships were developed to estimate carbon stock change during upcoming 100 years for Pinus densiflora, Pinus koraiensis, Pinus rigida, Larix kaempferi,and Quercus spp. The current forest volume was estimated with the developed regression model and 4th forest cover map. The future volume was predicted by developed volume-age models with adding n years to current age. As a result, we found that the total forest volume would increase from 126.89 m^3/ha to 246.61 m^3/ha and the carbon stocks would increase from 90.55 Mg C ha^(-1) to 174.62 Mg C ha^(-1) during 100 years when current forest remains unchanged. The carbon stocks would increase by approximately 0.84 Mg C ha^(-1) yr^(-1), which has high value if considering other northern countries' (Canada, Russia, China) -0.10 ~ 0.28 Mg C ha^(-1) yr^(-1) in pervious study. This can be attributed to the fact that mixed forest and bamboo forest in this study did not considered. Moreover, it must be influenced by that the change of carbon stocks was estimated without the consideration of mortality, thinning, and tree species' change in this study. ;

  5. Toward an integrated monitoring framework to assess the effects of tropical forest degradation and recovery on carbon stocks and biodiversity.

    Science.gov (United States)

    Bustamante, Mercedes M C; Roitman, Iris; Aide, T Mitchell; Alencar, Ane; Anderson, Liana O; Aragão, Luiz; Asner, Gregory P; Barlow, Jos; Berenguer, Erika; Chambers, Jeffrey; Costa, Marcos H; Fanin, Thierry; Ferreira, Laerte G; Ferreira, Joice; Keller, Michael; Magnusson, William E; Morales-Barquero, Lucia; Morton, Douglas; Ometto, Jean P H B; Palace, Michael; Peres, Carlos A; Silvério, Divino; Trumbore, Susan; Vieira, Ima C G

    2016-01-01

    Tropical forests harbor a significant portion of global biodiversity and are a critical component of the climate system. Reducing deforestation and forest degradation contributes to global climate-change mitigation efforts, yet emissions and removals from forest dynamics are still poorly quantified. We reviewed the main challenges to estimate changes in carbon stocks and biodiversity due to degradation and recovery of tropical forests, focusing on three main areas: (1) the combination of field surveys and remote sensing; (2) evaluation of biodiversity and carbon values under a unified strategy; and (3) research efforts needed to understand and quantify forest degradation and recovery. The improvement of models and estimates of changes of forest carbon can foster process-oriented monitoring of forest dynamics, including different variables and using spatially explicit algorithms that account for regional and local differences, such as variation in climate, soil, nutrient content, topography, biodiversity, disturbance history, recovery pathways, and socioeconomic factors. Generating the data for these models requires affordable large-scale remote-sensing tools associated with a robust network of field plots that can generate spatially explicit information on a range of variables through time. By combining ecosystem models, multiscale remote sensing, and networks of field plots, we will be able to evaluate forest degradation and recovery and their interactions with biodiversity and carbon cycling. Improving monitoring strategies will allow a better understanding of the role of forest dynamics in climate-change mitigation, adaptation, and carbon cycle feedbacks, thereby reducing uncertainties in models of the key processes in the carbon cycle, including their impacts on biodiversity, which are fundamental to support forest governance policies, such as Reducing Emissions from Deforestation and Forest Degradation.

  6. Evaluation of forest structure, biomass and carbon sequestration in subtropical pristine forests of SW China.

    Science.gov (United States)

    Nizami, Syed Moazzam; Yiping, Zhang; Zheng, Zheng; Zhiyun, Lu; Guoping, Yang; Liqing, Sha

    2017-03-01

    Very old natural forests comprising the species of Fagaceae (Lithocarpus xylocarpus, Castanopsis wattii, Lithocarpus hancei) have been prevailing since years in the Ailaoshan Mountain Nature Reserve (AMNR) SW China. Within these forest trees, density is quite variable. We studied the forest structure, stand dynamics and carbon density at two different sites to know the main factors which drives carbon sequestration process in old forests by considering the following questions: How much is the carbon density in these forest trees of different DBH (diameter at breast height)? How much carbon potential possessed by dominant species of these forests? How vegetation carbon is distributed in these forests? Which species shows high carbon sequestration? What are the physiochemical properties of soil in these forests? Five-year (2005-2010) tree growth data from permanently established plots in the AMNR was analysed for species composition, density, stem diameter (DBH), height and carbon (C) density both in aboveground and belowground vegetation biomass. Our study indicated that among two comparative sites, overall 54 species of 16 different families were present. The stem density, height, C density and soil properties varied significantly with time among the sites showing uneven distribution across the forests. Among the dominant species, L. xylocarpus represents 30% of the total carbon on site 1 while C. wattii represents 50% of the total carbon on site 2. The average C density ranged from 176.35 to 243.97 t C ha(-1). The study emphasized that there is generous degree to expand the carbon stocking in this AMNR through scientific management gearing towards conservation of old trees and planting of potentially high carbon sequestering species on good site quality areas.

  7. Changes in carbon balance after insect disturbance in Western U.S. forests

    Science.gov (United States)

    Trahan, N. A.; Moore, D. J. P.; Wilkes, P.; Quaife, T.; Desai, A. R.; Negron, J.; Stephens, B. B.; Elder, K.; Brayden, B. H.; Monson, R. K.

    2012-04-01

    Large scale tree mortality changes the balance between gross primary productivity (GPP) and total ecosystem respiration (TER). Mountain pine beetles (Dendroctonus ponderosae) have infested more than 86 million hectares of forest in the U.S.A. since 2000, leading to extensive tree mortality which is predicted to have important carbon, water and energy balance feedbacks on the Earth system. Current projections, based on models linked to changes in live tree stocks, suggest a sharp and prolonged transition of forest ecosystems from carbon sinks to significant carbon sources. We compared 9-year records of GPP and TER fluxes, and parallel disturbance chronosequences in two high elevation lodgepole pine forests in Colorado U.S.A., one impacted by the beetle (Fraser Experimental Forest) and a forest free of the outbreak (Niwot Ridge). We show that on a decadal scale the impact of this tree mortality on the carbon cycle is significantly less pronounced than these predictions because of a sustained suppression of respiration after mortality. We detect no increase in respiration after mortality from scales of several square meters up to an 84 km2 valley; rather we find a decline in both GPP and respiration suggesting a dampening of the carbon cycle. The sharp decline in respiration with GPP reflects the loss of autotrophic respiration and rhizodeposition occurring with tree mortality. We find a partial and transitory recovery of respiration 5-6 years after mortality, de-coupling respiration from concurrent GPP and associated with increased incorporation of C into soil organic matter. At the same time, trees that survive beetle outbreak undergo competitive release, allocating more carbon to growth in response to enhanced resource availability. In contrast to other disturbances like fire or logging, the impact of tree mortality caused by these biotic disturbances in Western North America is likely to have a subtle, long lasting impact on the carbon cycle which will require

  8. Short and Long Term Impacts of Forest Bioenergy Production on Atmospheric Carbon Dioxide Emissions

    Science.gov (United States)

    Hudiburg, T.; Law, B. E.; Luyssaert, S.; Thornton, P. E.

    2011-12-01

    Temperate forest annual net uptake of CO2 from the atmosphere is equivalent to ~16% of the annual fossil fuel emissions in the United States. Mitigation strategies to reduce emissions of carbon dioxide have lead to investigation of alternative sources of energy including forest biomass. The prospect of forest derived bioenergy has led to implementation of new forest management strategies based on the assumption that they will reduce total CO2 emissions to the atmosphere by simultaneously reducing the risk of wildfire and substituting for fossil fuels. The benefit of managing forests for bioenergy substitution of fossil fuels versus potential carbon sequestration by reducing harvest needs to be evaluated. This study uses a combination of Federal Forest Inventory data (FIA), remote sensing, and a coupled carbon-nitrogen ecosystem process model (CLM4-CN) to predict net atmospheric CO2 emissions from forest thinning for bioenergy production in Oregon under varying future management and climate scenarios. We use life-cycle assessment (LCA) incorporating both the forest and forest product sinks and sources of carbon dioxide. Future modeled results are compared with a reduced harvest scenario to determine the potential for increased carbon sequestration in forest biomass. We find that Oregon forests are a current strong sink of 7.5 ± 1.7 Tg C yr-1 or 61 g C m-2 yr-1. (NBP; NEP minus removals from fire and harvest). In the short term, we find that carbon dynamics following harvests for fire prevention and large-scale bioenergy production lead to 2-15% higher emissions over the next 20 years compared to current management, assuming 100% effectiveness of fire prevention. Given the current sink strength, analysis of the forest sector in Oregon demonstrates that increasing harvest levels by all practices above current business-as-usual levels increases CO2 emissions to the atmosphere as long as the region's sink persists. In the long-term, we find that projected changes in

  9. Estimating Forest Carbon Stock in Alpine and Arctic Ecotones of the Urals

    Directory of Open Access Journals (Sweden)

    V. A. Usoltsev

    2014-10-01

    assessing the income part of the carbon cycle in forests of alpine and arctic tree communities of the Ural region, as well as when validating the results of simulation experiments on evaluation of the carbon depositing capacity of forests.

  10. Biogeochemical Cycles of Carbon and Sulfur

    Science.gov (United States)

    DesMarais, David J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The elements carbon (C) and sulfur (S) interact with each other across a network of elemental reservoirs that are interconnected by an array of physical, chemical and biological processes. These networks are termed the biogeochemical C and S cycles. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. The element S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. This presentation describes the modern biogeochemical C and S cycles. Measurements are described whereby stable isotopes can help to infer the nature and quantitative significance of biological and geological processes involved in the C and S cycles. This lecture also summarizes the geological and climatologic aspects of the ancient C and S cycles, as well as the planetary and extraterrestrial processes that influenced their evolution over millions to billions of years.

  11. Biogeochemical Cycles of Carbon and Sulfur

    Science.gov (United States)

    DesMarais, David J.; DeVincenzi, D. (Technical Monitor)

    2002-01-01

    The elements carbon (C) and sulfur (S) interact with each other across a network of elemental reservoirs that are interconnected by an array of physical, chemical and biological processes. These networks are termed the biogeochemical C and S cycles. The compounds of C are highly important, not only as organic matter, but also as atmospheric greenhouse gases, pH buffers in seawater, oxidation-reduction buffers virtually everywhere, and key magmatic constituents affecting plutonism and volcanism. The element S assumes important roles as an oxidation-reduction partner with C and Fe in biological systems, as a key constituent in magmas and volcanic gases, and as a major influence upon pH in certain environments. This presentation describes the modern biogeochemical C and S cycles. Measurements are described whereby stable isotopes can help to infer the nature and quantitative significance of biological and geological processes involved in the C and S cycles. This lecture also summarizes the geological and climatologic aspects of the ancient C and S cycles, as well as the planetary and extraterrestrial processes that influenced their evolution over millions to billions of years.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Soil carbon storage following road removal and timber harvesting in redwood forests

    Science.gov (United States)

    Seney, Joseph; Madej, Mary Ann

    2015-01-01

    Soil carbon storage plays a key role in the global carbon cycle and is important for sustaining forest productivity. Removal of unpaved forest roads has the potential for increasing carbon storage in soils on forested terrain as treated sites revegetate and soil properties improve on the previously compacted road surfaces. We compared soil organic carbon (SOC) content at several depths on treated roads to SOC in adjacent second-growth forests and old-growth redwood forests in California, determined whether SOC in the upper 50 cm of soil varies with the type of road treatment, and assessed the relative importance of site-scale and landscape-scale variables in predicting SOC accumulation in treated road prisms and second-growth redwood forests. Soils were sampled at 5, 20, and 50 cm depths on roads treated by two methods (decommissioning and full recontouring), and in adjacent second-growth and old-growth forests in north coastal California. Road treatments spanned a period of 32 years, and covered a range of geomorphic and vegetative conditions. SOC decreased with depth at all sites. Treated roads on convex sites exhibited higher SOC than on concave sites, and north aspect sites had higher SOC than south aspect sites. SOC at 5, 20, and 50 cm depths did not differ significantly between decommissioned roads (treated 18–32 years previous) and fully recontoured roads (treated 2–12 years previous). Nevertheless, stepwise multiple regression models project higher SOC developing on fully recontoured roads in the next few decades. The best predictors for SOC on treated roads and in second-growth forest incorporated aspect, vegetation type, soil depth, lithology, distance from the ocean, years since road treatment (for the road model) and years since harvest (for the forest model). The road model explained 48% of the variation in SOC in the upper 50 cm of mineral soils and the forest model, 54%

  14. Wood energy fuel cycle optimization in beech and spruce forests

    Science.gov (United States)

    Meyer, Nickolas K.; Mina, Marco

    2012-03-01

    A novel synergistic approach to reducing emissions from residential wood combustion (RWC) is presented. Wood energy fuel cycle optimization (FCO) aims to provide cleaner burning fuels through optimization of forestry and renewable energy management practices. In this work, beech and spruce forests of average and high quality were modelled and analysed to determine the volume of fuel wood and its associated bark fraction produced during typical forestry cycles. Two separate fuel wood bark production regimes were observed for beech trees, while only one production regime was observed for spruce. The single tree and stand models were combined with existing thinning parameters to replicate existing management practices. Utilizing estimates of initial seedling numbers and existing thinning patterns a dynamic model was formed that responded to changes in thinning practices. By varying the thinning parameters, this model enabled optimization of the forestry practices for the reduction of bark impurities in the fuel wood supply chain. Beech forestry cycles responded well to fuel cycle optimization with volume reductions of bark from fuel wood of between ˜10% and ˜20% for average and high quality forest stands. Spruce, on the other hand, was fairly insensitive to FCO with bark reductions of 0-5%. The responsiveness of beech to FCO further supports its status as the preferred RWC fuel in Switzerland. FCO could easily be extended beyond Switzerland and applied across continental Europe and North America.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

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

    2008-01-01

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

  17. [Carbon storage of forest stands in Shandong Province estimated by forestry inventory data].

    Science.gov (United States)

    Li, Shi-Mei; Yang, Chuan-Qiang; Wang, Hong-Nian; Ge, Li-Qiang

    2014-08-01

    Based on the 7th forestry inventory data of Shandong Province, this paper estimated the carbon storage and carbon density of forest stands, and analyzed their distribution characteristics according to dominant tree species, age groups and forest category using the volume-derived biomass method and average-biomass method. In 2007, the total carbon storage of the forest stands was 25. 27 Tg, of which the coniferous forests, mixed conifer broad-leaved forests, and broad-leaved forests accounted for 8.6%, 2.0% and 89.4%, respectively. The carbon storage of forest age groups followed the sequence of young forests > middle-aged forests > mature forests > near-mature forests > over-mature forests. The carbon storage of young forests and middle-aged forests accounted for 69.3% of the total carbon storage. Timber forest, non-timber product forest and protection forests accounted for 37.1%, 36.3% and 24.8% of the total carbon storage, respectively. The average carbon density of forest stands in Shandong Province was 10.59 t x hm(-2), which was lower than the national average level. This phenomenon was attributed to the imperfect structure of forest types and age groups, i. e., the notably higher percentage of timber forests and non-timber product forest and the excessively higher percentage of young forests and middle-aged forest than mature forests.

  18. Decadally cycling soil carbon is more sensitive to warming than faster-cycling soil carbon.

    Science.gov (United States)

    Lin, Junjie; Zhu, Biao; Cheng, Weixin

    2015-12-01

    The response of soil organic carbon (SOC) pools to globally rising surface temperature crucially determines the feedback between climate change and the global carbon cycle. However, there is a lack of studies investigating the temperature sensitivity of decomposition for decadally cycling SOC which is the main component of total soil carbon stock and the most relevant to global change. We tackled this issue using two decadally (13) C-labeled soils and a much improved measuring system in a long-term incubation experiment. Results indicated that the temperature sensitivity of decomposition for decadally cycling SOC (>23 years in one soil and >55 years in the other soil) was significantly greater than that for faster-cycling SOC (<23 or 55 years) or for the entire SOC stock. Moreover, decadally cycling SOC contributed substantially (35-59%) to the total CO2 loss during the 360-day incubation. Overall, these results indicate that the decomposition of decadally cycling SOC is highly sensitive to temperature change, which will likely make this large SOC stock vulnerable to loss by global warming in the 21st century and beyond.

  19. Soil carbon model alternatives for ECHAM5/JSBACH climate model: Evaluation and impacts on global carbon cycle estimates

    Science.gov (United States)

    Thum, T.; RäIsäNen, P.; Sevanto, S.; Tuomi, M.; Reick, C.; Vesala, T.; Raddatz, T.; Aalto, T.; JäRvinen, H.; Altimir, N.; Pilegaard, K.; Nagy, Z.; Rambal, S.; Liski, J.

    2011-06-01

    The response of soil organic carbon to climate change might lead to significant feedbacks affecting global warming. This response can be studied by coupled climate-carbon cycle models but so far the description of soil organic carbon cycle in these models has been quite simple. In this work we used the coupled climate-carbon cycle model ECHAM5/JSBACH (European Center/Hamburg Model 5/Jena Scheme for Biosphere-Atmosphere Coupling in Hamburg) with two different soil carbon modules, namely (1) the original soil carbon model of JSBACH called CBALANCE and (2) a new soil carbon model Yasso07, to study the interaction between climate variability and soil organic carbon. Equivalent ECHAM5/JSBACH simulations were conducted using both soil carbon models, with freely varying atmospheric CO2 for the last 30 years (1977-2006). In this study, anthropogenic CO2 emissions and ocean carbon cycle were excluded. The new model formulation produced soil carbon stock estimates that were much closer to measured values. It also captured better the seasonal cycle of the direct CO2 exchange measurements at the three grassland sites considered (RMS error reduced by 12%), while for the five forest sites also analyzed, the results were ambiguous and the RMS error was 12% larger for Yasso07 than for CBALANCE. As a response to climatic changes, Yasso07 showed greater release of soil carbon to the atmosphere than the original model formulation during the years 1977-2006. This emphasizes the need for better understanding the processes affecting soil carbon stocks and their turnover rates to predict the climatic feedbacks.

  20. Ewing Symposium in Honor of Taro Takahashi: The controversial aspects of the contemporary [carbon] cycle

    Energy Technology Data Exchange (ETDEWEB)

    Broecker, Wallace Smith

    2001-12-31

    This Ewing Symposium in honor of Taro Takahashi's work on the carbon cycle was held at Lamont-Doherty Earth Observatory, Palisades, New York, on October 26-27, 2000. A program and set of abstracts are appended to this report. A summary of the meeting (included in this report) will be published in Global Biogeochemical Cycles. The theme of the symposium was the magnitude and cause of excess carbon storage on the north temperate continents. Disagreement exists on the relative roles of forest regrowth and fertilization by excess fixed nitrogen and carbon dioxide, as well as the distribution of this storage. Phenomena playing important roles include pre-anthropogenic gradients in carbon dioxide, the so-called rectification effect, uptake and release of carbon dioxide by the ocean, soil nitrogen dynamics, atmospheric carbon-13 gradients, and the role of fire.

  1. Ewing Symposium in Honor of Taro Takahashi: The controversial aspects of the contemporary [carbon] cycle

    Energy Technology Data Exchange (ETDEWEB)

    Broecker, Wallace Smith

    2001-12-31

    This Ewing Symposium in honor of Taro Takahashi's work on the carbon cycle was held at Lamont-Doherty Earth Observatory, Palisades, New York, on October 26-27, 2000. A program and set of abstracts are appended to this report. A summary of the meeting (included in this report) will be published in Global Biogeochemical Cycles. The theme of the symposium was the magnitude and cause of excess carbon storage on the north temperate continents. Disagreement exists on the relative roles of forest regrowth and fertilization by excess fixed nitrogen and carbon dioxide, as well as the distribution of this storage. Phenomena playing important roles include pre-anthropogenic gradients in carbon dioxide, the so-called rectification effect, uptake and release of carbon dioxide by the ocean, soil nitrogen dynamics, atmospheric carbon-13 gradients, and the role of fire.

  2. Variability of carbon and water fluxes following climate extremes over a tropical forest in southwestern Amazonia.

    Directory of Open Access Journals (Sweden)

    Marcelo Zeri

    Full Text Available The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010 and a flooding year (2009. The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha(-1 year(-1, but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change.

  3. Variability of carbon and water fluxes following climate extremes over a tropical forest in southwestern Amazonia.

    Science.gov (United States)

    Zeri, Marcelo; Sá, Leonardo D A; Manzi, Antônio O; Araújo, Alessandro C; Aguiar, Renata G; von Randow, Celso; Sampaio, Gilvan; Cardoso, Fernando L; Nobre, Carlos A

    2014-01-01

    The carbon and water cycles for a southwestern Amazonian forest site were investigated using the longest time series of fluxes of CO2 and water vapor ever reported for this site. The period from 2004 to 2010 included two severe droughts (2005 and 2010) and a flooding year (2009). The effects of such climate extremes were detected in annual sums of fluxes as well as in other components of the carbon and water cycles, such as gross primary production and water use efficiency. Gap-filling and flux-partitioning were applied in order to fill gaps due to missing data, and errors analysis made it possible to infer the uncertainty on the carbon balance. Overall, the site was found to have a net carbon uptake of ≈5 t C ha(-1) year(-1), but the effects of the drought of 2005 were still noticed in 2006, when the climate disturbance caused the site to become a net source of carbon to the atmosphere. Different regions of the Amazon forest might respond differently to climate extremes due to differences in dry season length, annual precipitation, species compositions, albedo and soil type. Longer time series of fluxes measured over several locations are required to better characterize the effects of climate anomalies on the carbon and water balances for the whole Amazon region. Such valuable datasets can also be used to calibrate biogeochemical models and infer on future scenarios of the Amazon forest carbon balance under the influence of climate change.

  4. Estimating national forest carbon stocks and dynamics: combining models and remotely sensed information

    Science.gov (United States)

    Smallman, Thomas Luke; Exbrayat, Jean-François; Bloom, Anthony; Williams, Mathew

    2017-04-01

    Forests are a critical component of the global carbon cycle, storing significant amounts of carbon, split between living biomass and dead organic matter. The carbon budget of forests is the most uncertain component of the global carbon cycle - it is currently impossible to quantify accurately the carbon source/sink strength of forest biomes due to their heterogeneity and complex dynamics. It has been a major challenge to generate robust carbon budgets across landscapes due to data scarcity. Models have been used for estimating carbon budgets, but outputs have lacked an assessment of uncertainty, making a robust assessment of their reliability and accuracy challenging. Here a Metropolis Hastings - Markov Chain Monte Carlo (MH-MCMC) data assimilation framework has been used to combine remotely sensed leaf area index (MODIS), biomass (where available) and deforestation estimates, in addition to forest planting information from the UK's national forest inventory, an estimate of soil carbon from the Harmonized World Database (HWSD) and plant trait information with a process model (DALEC) to produce a constrained analysis with a robust estimate of uncertainty of the UK forestry carbon budget between 2000 and 2010. Our analysis estimates the mean annual UK forest carbon sink at -3.9 MgC ha-1 yr-1 with a 95 % confidence interval between -4.0 and -3.1 MgC ha-1yr-1. The UK national forest inventory (NFI) estimates the mean UK forest carbon sink to be between -1.4 and -5.5 MgC ha-1 yr-1. The analysis estimate for total forest biomass stock in 2010 is estimated at 229 (177/232) TgC, while the NFI an estimated total forest biomass carbon stock of 216 TgC. Leaf carbon area (LCA) is a key plant trait which we are able to estimate using our analysis. Comparison of median estimates for (LCA) retrieved from the analysis and a UK land cover map show higher and lower values for LCA are estimated areas dominated by needle leaf and broad leaf forests forest respectively, consistent with

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

    NARCIS (Netherlands)

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

    2016-01-01

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

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

    NARCIS (Netherlands)

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

    2016-01-01

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

  7. Life Cycle Analysis of Carbon Flow and Carbon Footprint of Harvested Wood Products of Larix principis-rupprechtii in China

    Directory of Open Access Journals (Sweden)

    Fei Lun

    2016-03-01

    Full Text Available Larix principis-rupprechtii is a native tree species in North China with a large distribution; and its harvested timbers can be used for producing wood products. This study focused on estimating and comparing carbon flows and carbon footprints of different harvested wood products (HWPs from Larix principis-ruppechtii based on the life cycle analysis (from seedling cultivation to HWP final disposal. Based on our interviews and surveys, the system boundary in this study was divided into three processes: the forestry process, the manufacturing process, and the use and disposal process. By tracking carbon flows of HWPs along the entire life cycle, we found that, for one forest rotation period, a total of 26.81 tC/ha sequestered carbon was transferred into these HWPs, 66.2% of which were still stored in the HWP when the rotation period had ended; however, the HWP carbon storage decreased to 0.25 tC/ha (only 0.9% left in the 100th year after forest plantation. The manufacturing process contributed more than 90% of the total HWP carbon footprint, but it was still smaller than the HWP carbon storage. In terms of the carbon storage and the carbon footprint, construction products had the largest net positive carbon balance compared to furniture and panel products. In addition, HWP are known to have a positive impact on global carbon mitigation because they can store parts of the sequestered carbon for a certain period of time and they have a substitution effect on carbon mitigation. Furthermore, there still exist great opportunities for carbon mitigation from HWPs through the use of cleaner energy and increasing the utilization efficiency of wood fuel.

  8. Carbon cycle dynamics during recent interglacials

    Directory of Open Access Journals (Sweden)

    T. Kleinen

    2015-05-01

    Full Text Available Trends in the atmospheric concentration of CO2 during three recent interglacials, the Holocene, the Eemian and Marine Isotope Stage (MIS 11, are investigated using an Earth system Model of Intermediate Complexity, which we extended with modules to dynamically determine two slow carbon cycle processes – peat accumulation and shallow-water CaCO3 sedimentation (coral reef formation. For all three interglacials, model simulations considering peat accumulation and shallow water CaCO3 sedimentation substantially improve the agreement between model results and ice core CO2 reconstructions in comparison to a carbon cycle setup neglecting these processes. This enables us to model the trends in atmospheric CO2, with modelled trends similar to the ice core data, forcing the model only with orbital and sea level changes. During the Holocene, anthropogenic CO2 emissions are required to match the observed rise in atmospheric CO2 after 3 ka BP, but are not relevant before this time. Therefore our model experiments show for the first time how the CO2 evolution during the Holocene and two recent interglacials can be explained consistently using an identical model setup.

  9. An isopycnic ocean carbon cycle model

    Directory of Open Access Journals (Sweden)

    K. M. Assmann

    2010-02-01

    Full Text Available The carbon cycle is a major forcing component in the global climate system. Modelling studies, aiming to explain recent and past climatic changes and to project future ones, increasingly include the interaction between the physical and biogeochemical systems. Their ocean components are generally z-coordinate models that are conceptually easy to use but that employ a vertical coordinate that is alien to the real ocean structure. Here, we present first results from a newly-developed isopycnic carbon cycle model and demonstrate the viability of using an isopycnic physical component for this purpose. As expected, the model represents well the interior ocean transport of biogeochemical tracers and produces realistic tracer distributions. Difficulties in employing a purely isopycnic coordinate lie mainly in the treatment of the surface boundary layer which is often represented by a bulk mixed layer. The most significant adjustments of the ocean biogeochemistry model HAMOCC, for use with an isopycnic coordinate, were in the representation of upper ocean biological production. We present a series of sensitivity studies exploring the effect of changes in biogeochemical and physical processes on export production and nutrient distribution. Apart from giving us pointers for further model development, they highlight the importance of preformed nutrient distributions in the Southern Ocean for global nutrient distributions. The sensitivity studies show that iron limitation for biological particle production, the treatment of light penetration for biological production, and the role of diapycnal mixing result in significant changes of nutrient distributions and liniting factors of biological production.

  10. Forest conservation, afforestation and reforestation in India: Implications for forest carbon stocks

    Energy Technology Data Exchange (ETDEWEB)

    Ravindranath, N.H.; Chaturvedi, R.K.; Murthy, I.K. [Indian Institute of Science, Bangalore (India)

    2008-07-25

    India is a large developing country with a high population density and low forest area per capita. The livestock population density is among the highest in the world. Further, nearly 70% of the population residing in rural areas depends on forest and other biomass resources for fuel-wood, timber and non-timber forest products for its energy needs and livelihood. In such a socio-economic scenario, one would have expected the forest area to decline, leading to large emissions of CO{sub 2} from the forest sector. The analysis of forest cover, afforestation and reforestation has shown that the forest cover has stabilized in the past 15 years. The progressive conservation-oriented forest policies and afforestation programs are contributing to reduction in CO{sub 2} emissions to the atmosphere, stabilization of carbon stocks in forests and conservation of biodiversity. Thus, the Indian forest sector is projected to keep making positive contributions to global change and sustainable development. This article presents an assessment of the implications of past and current forest conservation and regeneration policies and programs for forest carbon sink in India. The area under forests, including part of the area afforested, is increasing and currently 67.83 mha of area is under forest cover. Assuming that the current trend continues, the area under forest cover is projected to reach 72 mha by 2030. Estimates of carbon stock in Indian forests in both soil and vegetation range from 8.58 to 9.57 GtC. The carbon stock in existing forests is projected to be nearly stable over the next 25 year period at 8.79 GtC. However, if the current rate of afforestation and reforestation is assumed to continue, the carbon stock could increase from 8.79 GtC in 2006 to 9.75 GtC by 2030 -- an increase of 11%. The estimates made in this study assume that the current trend will continue and do not include forest degradation and loss of carbon stock due to biomass extraction, fire, grazing and

  11. Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

    Directory of Open Access Journals (Sweden)

    X. Yang

    2010-04-01

    Full Text Available We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades

  12. Drought impact on forest carbon dynamics and fluxes in Amazonia.

    Science.gov (United States)

    Doughty, Christopher E; Metcalfe, D B; Girardin, C A J; Amézquita, F Farfán; Cabrera, D Galiano; Huasco, W Huaraca; Silva-Espejo, J E; Araujo-Murakami, A; da Costa, M C; Rocha, W; Feldpausch, T R; Mendoza, A L M; da Costa, A C L; Meir, P; Phillips, O L; Malhi, Y

    2015-03-05

    In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the

  13. Carbon and nitrogen isotope variations in tree-rings as records of perturbations in regional carbon and nitrogen cycles.

    Science.gov (United States)

    Bukata, Andrew R; Kyser, T Kurtis

    2007-02-15

    Increasing anthropogenic pollution from urban centers and fossil fuel combustion can impact the carbon and nitrogen cycles in forests. To assess the impact of twentieth century anthropogenic pollution on forested system carbon and nitrogen cycles, variations in the carbon and nitrogen isotopic compositions of tree-rings were measured. Individual annual growth rings in trees from six sites across Ontario and one in New Brunswick, Canada were used to develop site chronologies of tree-ring delta 15N and delta 13C values. Tree-ring 615N values were approximately 0.5% per hundred higher and correlated with contemporaneous foliar samples from the same tree, but not with delta 15N values of soil samples. Temporal trends in carbon and nitrogen isotopic compositions of these tree-rings are consistent with increasing anthropogenic influence on both the carbon and nitrogen cycles since 1945. Tree-ring delta 13C values and delta 15N values are correlated at both remote and urban-proximal sites, with delta 15N values decreasing since 1945 and converging on 1% per hundred at urban-proximal sites and decreasing but not converging on a single delta 15N value in remote sites. These results indicate that temporal trends in tree-ring nitrogen and carbon isotopic compositions record the regional extent of pollution.

  14. Correlation analysis between forest carbon stock and spectral vegetation indices in Xuan Lien Nature Reserve, Thanh Hoa, Viet Nam

    Science.gov (United States)

    Dung Nguyen, The; Kappas, Martin

    2017-04-01

    In the last several years, the interest in forest biomass and carbon stock estimation has increased due to its importance for forest management, modelling carbon cycle, and other ecosystem services. However, no estimates of biomass and carbon stocks of deferent forest cover types exist throughout in the Xuan Lien Nature Reserve, Thanh Hoa, Viet Nam. This study investigates the relationship between above ground carbon stock and different vegetation indices and to identify the most likely vegetation index that best correlate with forest carbon stock. The terrestrial inventory data come from 380 sample plots that were randomly sampled. Individual tree parameters such as DBH and tree height were collected to calculate the above ground volume, biomass and carbon for different forest types. The SPOT6 2013 satellite data was used in the study to obtain five vegetation indices NDVI, RDVI, MSR, RVI, and EVI. The relationships between the forest carbon stock and vegetation indices were investigated using a multiple linear regression analysis. R-square, RMSE values and cross-validation were used to measure the strength and validate the performance of the models. The methodology presented here demonstrates the possibility of estimating forest volume, biomass and carbon stock. It can also be further improved by addressing more spectral bands data and/or elevation.

  15. Expanding the Long-term Carbon Sequestration Capacity of Terrestrial Forests: Restoring the Balance.

    Science.gov (United States)

    Scher, S.

    2008-12-01

    For millions of years, the Global Carbon Cycle maintained a balance between energy absorbed from the sun and emitted to space. With the advent of the industrial revolution, changes in land use, deforestation, and emissions from combustion of carbon-based fossil fuels contributed to the current imbalance estimated at 0.85 Watts per meter squared. The long residence time of carbon dioxide in the atmosphere and thermal inertia of the oceans provide compelling reasons to expect the current imbalance to persist for centuries, possibly millennia. Proposed reductions in future emissions fail to address the historic accumulation and persistence of CO2 in the atmosphere. Expanding the carbon sequestration capacity of terrestrial forests represents a long-term approach to restoring the balance. The only proven forest resources with the capacity to store carbon over time-scales of centuries to millennia are the old-growth forests of the Pacific Northwest, ancient redwood/sequoia forests native to California, and possibly a few other conifers. Restoring the balance compels us to prevent further deforestation, conserve existing stands of old-growth and ancient redwoods, establish global programs of reforestation with long-lived trees and promote longer rotation periods for existing forests.

  16. Estimating national forest carbon stocks and dynamics: combining models and remotely sensed information

    Science.gov (United States)

    Smallman, Luke; Williams, Mathew

    2016-04-01

    Forests are a critical component of the global carbon cycle, storing significant amounts of carbon, split between living biomass and dead organic matter. The carbon budget of forests is the most uncertain component of the global carbon cycle - it is currently impossible to quantify accurately the carbon source/sink strength of forest biomes due to their heterogeneity and complex dynamics. It has been a major challenge to generate robust carbon budgets across landscapes due to data scarcity. Models have been used but outputs have lacked an assessment of uncertainty, making a robust assessment of their reliability and accuracy challenging. Here a Metropolis Hastings - Markov Chain Monte Carlo (MH-MCMC) data assimilation framework has been used to combine remotely sensed leaf area index (MODIS), biomass (where available) and deforestation estimates, in addition to forest planting and clear-felling information from the UK's national forest inventory, an estimate of soil carbon from the Harmonized World Database (HWSD) and plant trait information with a process model (DALEC) to produce a constrained analysis with a robust estimate of uncertainty of the UK forestry carbon budget between 2000 and 2010. Our analysis estimates the mean annual UK forest carbon sink at -3.9 MgC ha-1yr-1 with a 95 % confidence interval between -4.0 and -3.1 MgC ha-1 yr-1. The UK national forest inventory (NFI) estimates the mean UK forest carbon sink to be between -1.4 and -5.5 MgC ha-1 yr-1. The analysis estimate for total forest biomass stock in 2010 is estimated at 229 (177/232) TgC, while the NFI an estimated total forest biomass carbon stock of 216 TgC. Leaf carbon area (LCA) is a key plant trait which we are able to estimate using our analysis. Comparison of median estimates for LCA retrieved from the analysis and a UK land cover map show higher and lower values for LCA are estimated areas dominated by needle leaf and broad leaf forests forest respectively, consistent with ecological

  17. Terrestrial carbon losses from mountaintop coal mining offset regional forest carbon sequestration in the 21st century

    Science.gov (United States)

    Campbell, J. Elliott; Fox, James F.; Acton, Peter M.

    2012-12-01

    Studies that quantify the spatial and temporal variability of carbon sources and sinks provide process-level information for the prediction of future levels of atmospheric carbon dioxide as well as verification of current emission agreements. Assessments of carbon sources and sinks for North America that compare top-down atmospheric constraints with bottom-up inventories find particularly large carbon sinks in the southeastern US. However, this southeastern US sink may be impacted by extreme land-use disturbance events due to mountaintop coal mining (MCM). Here we apply ecosystem modeling and field experiment data to quantify the potential impact of future mountaintop coal mining on the carbon budget of the southern Appalachian forest region. For projections based on historical mining rates, grassland reclamation, and the continued regrowth of un-mined forests, we find that the southern Appalachian forests switch from a net carbon sink to a net carbon source by year 2025-33 with a 30%-35% loss in terrestrial carbon stocks relative to a scenario with no future mining by the year 2100. Alternatively, scenarios of forest sequestration due to the effect of CO2 fertilization result in a 15%-24% loss in terrestrial carbon stocks by the year 2100 for mining scenarios relative to scenarios with no future mining. These results suggest that while power plant stack emissions are the dominant life-cycle stage in coal-fired electricity, accounting for mountaintop coal mining in bottom-up inventories may be a critical component of regional carbon budgets.

  18. Carbon balance of rewetted peatland forests in low mountain range areas, Germany

    Science.gov (United States)

    Krüger, Jan Paul; Dotterweich, Markus; Kopf, Christoph; Schüler, Gebhard; Scherzer, Jörg

    2017-04-01

    Peatland soils store a great proportion of the global soil carbon pool and are an important component of the global carbon cycle. Drainage of peatlands, for agricultural or forestry usage, leads to a loss of carbon from the soil to the atmosphere and the former carbon sink becomes a carbon source. Peatland rewetting has become a well applicable management tool to reduce the greenhouse gas emissions from peatland soils. However, the impact of rewetting on the carbon balance of drained peatland forest in low mountain range is rare. The aim of this project is to quantify the carbon balance of rewetted peatlands in the Hunsrück-Hochwald National Park. Worth protecting peatland's with forest called "Brücher" are characteristic of nature in the Hunsrück. Since the 19th century these peatlands have been drained by ditches for spruce forests. The survey of surface area of the peatlands is the first important part of the project. Furthermore, a peatland land register for the national park and adjacent areas will be developed. Based on peatland area and carbon stocks the carbon pools of different degradation stages of these peatland can be investigated. Furthermore, terrestrial laser scan data and geoelectrical measurements will be applied for estimating the carbon pool of the vegetation and the soil. This approach enables us to quantify the whole ecosystem carbon pool. A space-for-time substitution allows for a first estimation of the carbon balance of the rewetted peatlands in the Hunsrück-Hochwald National Park. The main aim of a comprehensive carbon balancing will be achieved based upon the peatland characteristics and upscaling of carbon stocks from peatlands with different restoration/degradation scenarios. Moreover, the obtained data will be used for a long-term carbon balance monitoring of the rewetted peatlands in this region.

  19. Human impacts on soil carbon dynamics of deep-rooted Amazonian forests

    Science.gov (United States)

    Nepstad, Daniel C.; Stone, Thomas A.; Davidson, Eric A.

    1994-01-01

    Deforestation and logging degrade more forest in eastern and southern Amazonia than in any other region of the world. This forest alteration affects regional hydrology and the global carbon cycle, but our current understanding of these effects is limited by incomplete knowledge of tropical forest ecosystems. It is widely agreed that roots are concentrated near the soil surface in moist tropical forests, but this generalization incorrectly implies that deep roots are unimportant in water and C budgets. Our results indicate that half of the closed-canopy forests of Brazilian Amazonic occur where rainfall is highly seasonal, and these forests rely on deeply penetrating roots to extract soil water. Pasture vegetation extracts less water from deep soil than the forest it replaces, thus increasing rates of drainage and decreasing rates of evapotranspiration. Deep roots are also a source of modern carbon deep in the soil. The soils of the eastern Amazon contain more carbon below 1 m depth than is present in above-ground biomass. As much as 25 percent of this deep soil C could have annual to decadal turnover times and may be lost to the atmosphere following deforestation. We compared the importance of deep roots in a mature, evergreen forest with an adjacent man-made pasture, the most common type of vegetation on deforested land in Amazonia. The study site is near the town of Paragominas, in the Brazilian state of Para, with a seasonal rainfall pattern and deeply-weathered, kaolinitic soils that are typical for large portions of Amazonia. Root distribution, soil water extraction, and soil carbon dynamics were studied using deep auger holes and shafts in each ecosystem, and the phenology and water status of the leaf canopies were measured. We estimated the geographical distribution of deeply-rooting forests using satellite imagery, rainfall data, and field measurements.

  20. Annual carbon balance of Canada's forests during 1895–1996

    National Research Council Canada - National Science Library

    Chen, Jing; Chen, Wenjun; Liu, Jane; Cihlar, Josef; Gray, Stephen

    2000-01-01

    This paper reports annual carbon (C) balance of Canada's forests during 1895–1996 estimated using the Integrated Terrestrial Ecosystem C‐budget model (InTEC) [ Chen et al. this issue]. During 1895...

  1. Black silicon maskless templates for carbon nanotube forests

    DEFF Research Database (Denmark)

    Wierzbicki, Rafal; Schmidt, Michael Stenbæk; Boisen, Anja

    2013-01-01

    We present here a proof of concept for a novel fabrication method of vertically aligned carbon nanotube forests, utilizing black silicon nanograss (a forest of silicon nanometer-sized spikes created with reactive ion etching) coated with titanium tungsten diffusion barrier as a template. The meth...

  2. Energy dissipation in intercalated carbon nanotube forests with metal layers

    Science.gov (United States)

    Vertically aligned carbon nanotube (CNT) forests were synthesized to study their quasi-static mechanical properties in a layered configuration with metallization. The top and bottom surfaces of CNT forests were metalized with Ag, Fe, and In using paste, sputtering, and thermal evaporation, respectiv...

  3. Effects of fuel and forest conservation on future levels of atmospheric carbon dioxide.

    Science.gov (United States)

    Walker, J C; Kasting, J F

    1992-01-01

    We develop a numerical simulation of the global biogeochemical cycles of carbon that works over time scales extending from years to millions of years. The ocean is represented by warm and cold shallow water reservoirs, a thermocline reservoir, and deep Atlantic, Indian, and Pacific reservoirs. The atmosphere is characterized by a single carbon reservoir and the global biota by a single biomass reservoir. The simulation includes the rock cycle, distinguishing between shelf carbonate and pelagic carbonate precipitation, with distinct lysocline depths in the three deep ocean reservoirs. Dissolution of pelagic carbonates in response to decrease in lysocline depth is included. The simulation is tuned to reproduce the observed radiocarbon record resulting from atomic weapon testing. It is tuned also to reproduce the distribution of dissolved phosphate and total dissolved carbon between the ocean reservoirs as well as the carbon isotope ratios for both 13C and 14C in ocean and atmosphere. The simulation reproduces reasonably well the historical record of carbon dioxide partial pressure as well as the atmospheric isotope ratios for 13C and 14C over the last 200 yr as these have changed in response to fossil fuel burning and land use changes, principally forest clearance. The agreements between observation and calculation involves the assumption of a carbon dioxide fertilization effect in which the rate of production of biomass increases with increasing carbon dioxide partial pressure. At present the fertilization effect of increased carbon dioxide outweighs the effects of forest clearance, so the biota comprises an overall sink of atmospheric carbon dioxide sufficiently large to bring the budget approximately into balance. This simulation is used to examine the future evolution of carbon dioxide and its sensitivity to assumptions about the rate of fossil fuel burning and of forest clearance. Over times extending up to thousands of years, the results are insensitive to the

  4. Carbon carry capacity and carbon sequestration potential in China based on an integrated analysis of mature forest biomass.

    Science.gov (United States)

    Liu, YingChun; Yu, GuiRui; Wang, QiuFeng; Zhang, YangJian; Xu, ZeHong

    2014-12-01

    Forests play an important role in acting as a carbon sink of terrestrial ecosystem. Although global forests have huge carbon carrying capacity (CCC) and carbon sequestration potential (CSP), there were few quantification reports on Chinese forests. We collected and compiled a forest biomass dataset of China, a total of 5841 sites, based on forest inventory and literature search results. From the dataset we extracted 338 sites with forests aged over 80 years, a threshold for defining mature forest, to establish the mature forest biomass dataset. After analyzing the spatial pattern of the carbon density of Chinese mature forests and its controlling factors, we used carbon density of mature forests as the reference level, and conservatively estimated the CCC of the forests in China by interpolation methods of Regression Kriging, Inverse Distance Weighted and Partial Thin Plate Smoothing Spline. Combining with the sixth National Forest Resources Inventory, we also estimated the forest CSP. The results revealed positive relationships between carbon density of mature forests and temperature, precipitation and stand age, and the horizontal and elevational patterns of carbon density of mature forests can be well predicted by temperature and precipitation. The total CCC and CSP of the existing forests are 19.87 and 13.86 Pg C, respectively. Subtropical forests would have more CCC and CSP than other biomes. Consequently, relying on forests to uptake carbon by decreasing disturbance on forests would be an alternative approach for mitigating greenhouse gas concentration effects besides afforestation and reforestation.

  5. Intact tropical forests, new evidence they uptake carbon actively

    Directory of Open Access Journals (Sweden)

    2009-03-01

    Full Text Available According to a paper recently published on Nature, tropical forests play as active carbon sink, absorbing 1.3·109 tons of carbon per year on a global scale. Functional interpretation is not clear yet, but a point is quite easy to realize: tropical forests accumulate and contain more carbon than any other vegetation cover and, if their disruption goes on at current rates, these ecosystems could revert to be a “carbon bomb”, releasing huge amount of CO2 to the atmosphere.

  6. Iron, phytoplankton growth, and the carbon cycle.

    Science.gov (United States)

    Street, Joseph H; Paytan, Adina

    2005-01-01

    Iron is an essential nutrient for all living organisms. Iron is required for the synthesis of chlorophyll and of several photosynthetic electron transport proteins and for the reduction of CO2, SO4(2-), and NO3(-) during the photosynthetic production of organic compounds. Iron concentrations in vast areas of the ocean are very low (iron in oxic seawater. Low iron concentrations have been shown to limit primary production rates, biomass accumulation, and ecosystem structure in a variety of open-ocean environments, including the equatorial Pacific, the subarctic Pacific and the Southern Ocean and even in some coastal areas. Oceanic primary production, the transfer of carbon dioxide into organic carbon by photosynthetic plankton (phytoplankton), is one process by which atmospheric CO2 can be transferred to the deep ocean and sequestered for long periods of time. Accordingly, iron limitation of primary producers likely plays a major role in the global carbon cycle. It has been suggested that variations in oceanic primary productivity, spurred by changes in the deposition of iron in atmospheric dust, control atmospheric CO2 concentrations, and hence global climate, over glacial-interglacial timescales. A contemporary application of this "iron hypothesis" promotes the large-scale iron fertilization of ocean regions as a means of enhancing the ability of the ocean to store anthropogenic CO2 and mitigate 21st century climate change. Recent in situ iron enrichment experiments in the HNLC regions, however, cast doubt on the efficacy and advisability of iron fertilization schemes. The experiments have confirmed the role of iron in regulating primary productivity, but resulted in only small carbon export fluxes to the depths necessary for long-term sequestration. Above all, these experiments and other studies of iron biogeochemistry over the last two decades have begun to illustrate the great complexity of the ocean system. Attempts to engineer this system are likely to

  7. Influence of soil moisture-carbon cycle interactions on the terrestrial carbon cycle over Europe

    Science.gov (United States)

    Mystakidis, Stefanos; Davin, Edouard L.; Gruber, Nicolas; Seneviratne, Sonia I.

    2016-04-01

    Water availability is a crucial limiting factor for terrestrial ecosystems, but relatively few studies have quantitatively assessed the influence of soil moisture variability on the terrestrial carbon cycle. Here, we investigate the role of soil moisture variability and state in the contemporary terrestrial carbon cycle over Europe. For this we use a Regional Earth System Model (RESM) based on the COSMO-CLM Regional Climate Model, coupled to the Community Land Model version 4.0 (CLM4.0) and its carbon-nitrogen module. The simulation setup consists of a control simulation over the period 1979-2010 in which soil moisture is interactive and three sensitivity simulations in which soil moisture is prescribed to a mean, a very dry or a very wet seasonal cycle without inter-annual variability. The cumulative net biome productivity varies markedly between the different experiments ranging from a strong sink of up to 6PgC in the wet experiment to a source of up to 1.2PgC in the dry experiment. Changes in the land carbon uptake are driven by a combination of two factors: the direct impact of soil moisture on plant's carbon uptake (essentially in southern Europe) and an indirect effect through changes in temperature affecting ecosystem respiration (mainly in central and northern Europe). We find that removing temporal variations in soil moisture dampens interannual variations in terrestrial carbon fluxes (Gross Primary Productivity, respiration, Net Biome Productivity) by more than 50% over most of Europe. Moreover, the analysis reveals that on annual scale about two-thirds of central Europe and about 70% of southern Europe display statistically significant effect of drying and/or wetting on the terrestrial carbon budget and its components. Our findings confirm the crucial role of soil moisture in determining the magnitude and the inter-annual variability in land CO2 uptake which is a key contributor to the year-to-year variations in atmospheric CO2 concentration.

  8. Calculating Organic Carbon Stock from Forest Soils

    Directory of Open Access Journals (Sweden)

    Lucian Constantin DINCĂ

    2015-12-01

    Full Text Available The organic carbon stock (SOC (t/ha was calculated in different approaches in order to enhance the differences among methods and their utility regarding specific studies. Using data obtained in Romania (2000-2012 from 4,500 profiles and 9,523 soil horizons, the organic carbon stock was calculated for the main forest soils (18 types using three different methods: 1 on pedogenetical horizons, by soil bulk density and depth class/horizon thickness; 2 by soil type and standard depths; 3 using regression equations between the quantity of organic C and harvesting depths. Even though the same data were used, the differences between the values of C stock obtained from the three methods were relatively high. The first method led to an overvaluation of the C stock. The differences between methods 1 and 2 were high (and reached 33% for andosol, while the differences between methods 2 and 3 were smaller (a maximum of 23% for rendzic leptosol. The differences between methods 2 and 3 were significantly lower especially for andosol, arenosol and vertisol. A thorough analysis of all three methods concluded that the best method to evaluate the organic C stock was to distribute the obtained values on the following standard depths: 0 - 10 cm; 10 - 20 cm; 20 - 40 cm; > 40 cm. For each soil type, a correlation between the quantity of organic C and the sample harvesting depth was also established. These correlations were significant for all types of soil; however, lower correlation coefficients were registered for rendzic leptosol, haplic podzol and fluvisol.

  9. A framework for assessing global change risks to forest carbon stocks in the United States.

    Science.gov (United States)

    Woodall, Christopher W; Domke, Grant M; Riley, Karin L; Oswalt, Christopher M; Crocker, Susan J; Yohe, Gary W

    2013-01-01

    Among terrestrial environments, forests are not only the largest long-term sink of atmospheric carbon (C), but are also susceptible to global change themselves, with potential consequences including alterations of C cycles and potential C emission. To inform global change risk assessment of forest C across large spatial/temporal scales, this study constructed and evaluated a basic risk framework which combined the magnitude of C stocks and their associated probability of stock change in the context of global change across the US. For the purposes of this analysis, forest C was divided into five pools, two live (aboveground and belowground biomass) and three dead (dead wood, soil organic matter, and forest floor) with a risk framework parameterized using the US's national greenhouse gas inventory and associated forest inventory data across current and projected future Köppen-Geiger climate zones (A1F1 scenario). Results suggest that an initial forest C risk matrix may be constructed to focus attention on short- and long-term risks to forest C stocks (as opposed to implementation in decision making) using inventory-based estimates of total stocks and associated estimates of variability (i.e., coefficient of variation) among climate zones. The empirical parameterization of such a risk matrix highlighted numerous knowledge gaps: 1) robust measures of the likelihood of forest C stock change under climate change scenarios, 2) projections of forest C stocks given unforeseen socioeconomic conditions (i.e., land-use change), and 3) appropriate social responses to global change events for which there is no contemporary climate/disturbance analog (e.g., severe droughts in the Lake States). Coupling these current technical/social limits of developing a risk matrix to the biological processes of forest ecosystems (i.e., disturbance events and interaction among diverse forest C pools, potential positive feedbacks, and forest resiliency/recovery) suggests an operational forest C

  10. A framework for assessing global change risks to forest carbon stocks in the United States.

    Directory of Open Access Journals (Sweden)

    Christopher W Woodall

    Full Text Available Among terrestrial environments, forests are not only the largest long-term sink of atmospheric carbon (C, but are also susceptible to global change themselves, with potential consequences including alterations of C cycles and potential C emission. To inform global change risk assessment of forest C across large spatial/temporal scales, this study constructed and evaluated a basic risk framework which combined the magnitude of C stocks and their associated probability of stock change in the context of global change across the US. For the purposes of this analysis, forest C was divided into five pools, two live (aboveground and belowground biomass and three dead (dead wood, soil organic matter, and forest floor with a risk framework parameterized using the US's national greenhouse gas inventory and associated forest inventory data across current and projected future Köppen-Geiger climate zones (A1F1 scenario. Results suggest that an initial forest C risk matrix may be constructed to focus attention on short- and long-term risks to forest C stocks (as opposed to implementation in decision making using inventory-based estimates of total stocks and associated estimates of variability (i.e., coefficient of variation among climate zones. The empirical parameterization of such a risk matrix highlighted numerous knowledge gaps: 1 robust measures of the likelihood of forest C stock change under climate change scenarios, 2 projections of forest C stocks given unforeseen socioeconomic conditions (i.e., land-use change, and 3 appropriate social responses to global change events for which there is no contemporary climate/disturbance analog (e.g., severe droughts in the Lake States. Coupling these current technical/social limits of developing a risk matrix to the biological processes of forest ecosystems (i.e., disturbance events and interaction among diverse forest C pools, potential positive feedbacks, and forest resiliency/recovery suggests an operational

  11. Simulation and comparison of forest carbon sequestration in the United States and China in recent decades

    Science.gov (United States)

    Liu, Jinxun; Sleeter, Benjamin; Zhu, Zhiliang; Hawbaker, Todd; Zhu, Qiuan; Ju, Weimin; Wilson, Tamara; Sherba, Jason; Xin, Xiaoping; Gong, Peng; Chen, Jing

    2016-04-01

    Terrestrial ecosystems sequester roughly 30% of anthropogenic carbon emissions globally. While climate change is believed to drive ecosystem carbon cycles, land use and land cover (LULC) changes are becoming increasingly recognized as dominant drivers as well. The United States and China are the top two CO2 emitting countries in the world. On the other hand, the two countries both have tremendous land extent and thus enormous potential to sequester carbon. In this study, we focused on quantifying and comparing the climate effect and the LULC change effect on forest carbon sequestration in the two countries. The process-based Integrated Biosphere Simulator (IBIS) was used to simulate the effects of atmospheric CO2 fertilization, nitrogen deposition, climate change, fire disturbance, logging, and deforestation/reforestation on ecosystem carbon changes. Output variables included carbon stocks, such as live and dead biomass, and carbon fluxes, such as fire carbon combustion, logging removal, net ecosystem productivity (NPP) and net biome productivity (NBP). A comprehensive environmental input spatial dataset (1-km to 10-km resolution) was developed and used in IBIS, which included land cover change information derived from the Landsat data archive (1973 -2010), wildland fire scar and burn severity information (1984-2010), forest canopy percentage and live biomass (~2000), spatially heterogeneous atmospheric CO2 concentration and nitrogen deposition (2003-2009), and newly available climate and soil variables. In addition, forest field inventory data were used to calibrate the IBIS model. Initial comparison of results indicate that although the two countries have significant differences in forest land area, forest age structure, biomass stock level, and disturbance type, the overall annual carbon sequestration rates are comparable.

  12. Carbon allocation patterns in boreal and hemiboreal forest ecosystems along the gradient of soil fertility

    Science.gov (United States)

    Kriiska, Kaie; Uri, Veiko; Frey, Jane; Napa, Ülle; Kabral, Naima; Soosaar, Kaido; Rannik, Kaire; Ostonen, Ivika

    2017-04-01

    Carbon (C) allocation plays a critical role in forest ecosystem carbon cycling. Changes in C allocation alter ecosystems carbon sequestration and plant-soil-atmosphere gas exchange, hence having an impact on the climate. Currently, there is lack of reliable indicators that show the direction of C accumulation patterns in forest ecosystems on regional scale. The first objective of our study was to determine the variability of carbon allocation in hemiboreal coniferous forests along the gradient of soil fertility in Estonia. We measured C stocks and fluxes, such as litter, fine root biomass and production, soil respiration etc. in 8 stands of different site types - Scots pine (Cladonia, Vaccinium, Myrtillus, Fragaria) and Norway spruce (Polytrichum, Myrtillus, Oxalis, Calamagrostis alvar). The suitability of above- and belowground litter production (AG/BG) ratio was analysed as a carbon allocation indicator. The second aim of the study was to analyse forest C allocation patterns along the north-south gradient from northern boreal Finland to hemiboreal Estonia. Finally, C sequestration in silver birch and grey alder stands were compared with coniferous stands in order to determine the impact of tree species on carbon allocation. Preliminary results indicate that estimated AG/BG ratio (0.5 ... 3.0) tends to decrease with increasing soil organic horizon C/N ratio, indicating that in less fertile sites more carbon is allocated into belowground through fine root growth and in consequence the soil organic carbon stock increases. Similar trends were found on the north-south forest gradient. However, there was a significant difference between coniferous and broadleaf stands in C allocation patterns. Net ecosystem exchange in Estonian coniferous stands varied from -1.64 ... 3.95 t C ha-1 yr-1, whereas older stands tended to be net carbon sources.

  13. Carbon neutral? No change in mineral soil carbon stock under oil palm plantations derived from forest or non-forest in Indonesia

    NARCIS (Netherlands)

    Khasanah, N.; Noordwijk, van M.; Ningsih, H.; Rahayu, S.

    2015-01-01

    Sustainability criteria for palm oil production guide new planting toward non-forest land cover on mineral soil, avoiding carbon debts caused by forest and peat conversion. Effects on soil carbon stock (soil Cstock) of land use change trajectories from forest and non-forest to oil palm on mineral so

  14. A Tale of Two “Forests”: Random Forest Machine Learning Aids Tropical Forest Carbon Mapping

    Science.gov (United States)

    Mascaro, Joseph; Asner, Gregory P.; Knapp, David E.; Kennedy-Bowdoin, Ty; Martin, Roberta E.; Anderson, Christopher; Higgins, Mark; Chadwick, K. Dana

    2014-01-01

    Accurate and spatially-explicit maps of tropical forest carbon stocks are needed to implement carbon offset mechanisms such as REDD+ (Reduced Deforestation and Degradation Plus). The Random Forest machine learning algorithm may aid carbon mapping applications using remotely-sensed data. However, Random Forest has never been compared to traditional and potentially more reliable techniques such as regionally stratified sampling and upscaling, and it has rarely been employed with spatial data. Here, we evaluated the performance of Random Forest in upscaling airborne LiDAR (Light Detection and Ranging)-based carbon estimates compared to the stratification approach over a 16-million hectare focal area of the Western Amazon. We considered two runs of Random Forest, both with and without spatial contextual modeling by including—in the latter case—x, and y position directly in the model. In each case, we set aside 8 million hectares (i.e., half of the focal area) for validation; this rigorous test of Random Forest went above and beyond the internal validation normally compiled by the algorithm (i.e., called “out-of-bag”), which proved insufficient for this spatial application. In this heterogeneous region of Northern Peru, the model with spatial context was the best preforming run of Random Forest, and explained 59% of LiDAR-based carbon estimates within the validation area, compared to 37% for stratification or 43% by Random Forest without spatial context. With the 60% improvement in explained variation, RMSE against validation LiDAR samples improved from 33 to 26 Mg C ha−1 when using Random Forest with spatial context. Our results suggest that spatial context should be considered when using Random Forest, and that doing so may result in substantially improved carbon stock modeling for purposes of climate change mitigation. PMID:24489686

  15. Capacity of US Forests to Maintain Existing Carbon Sequestration will be affected by Changes in Forest Disturbances and to a greater extent, the Economic and Societal Influences on Forest Management and Land Use

    Science.gov (United States)

    Joyce, L. A.; Running, S. W.; Breshears, D. D.; Dale, V.; Malmsheimer, R. W.; Sampson, N.; Sohngen, B.; Woodall, C. W.

    2012-12-01

    -growing planting stock and shorter rotations, and weed, disease, and insect control, and increasing the interval between harvests or decreasing harvest intensity. Economic drivers will affect future carbon cycle of forests such as shifts in forest age class structure in response to markets, land-use changes such as urbanization, and forest type changes. Future changes in forestland objectives include the potential for bioenergy based on forestland resources, which is as large as 504 million acres of timberland and 91 million acres of other forest land out of the 751 million acres of U.S. forestland. Implications of forest product use for bioenergy depend on the context of specific locations such as feedstock type and prior management, land conditions, transport and storage logistics, conversion processes used to produce energy, distribution and use. Markets for energy from biomass appear to be ready to grow in response to energy pricing, policy and demand, although recent increases in the supply of natural gas have reduced urgency for new biomass projects. Beyond use in the forest industry and some residences, biopower is not a large-scale enterprise in the United States. Societal choices about forest policy will also affect the carbon cycles on public and private forestland.

  16. State and Potential of Forest Carbon Market in China

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    China has been making efforts to improve climate changes which have drawn international attentions since China formally signed UN Climate Change Framework in 1992 and ratified Kyoto Protocol in August 2002. The area of China’s forest plantation ranks the first at present so global close attention is paid to forest carbon market in China. This article introduces that 5 110 million t of carbon dioxide equivalent have been sequestrated by China’s forest during 1980 to 2005, China will have 4.2 billion t of car...

  17. Influence of bark beetles outbreaks on the carbon balance of western United States forests

    Science.gov (United States)

    Ghimire, B.; Williams, C. A.; Collatz, G. J.; Masek, J. G.

    2011-12-01

    Recently bark beetle outbreaks have been increasing in western United States forests due to increases in temperatures and prolonged occurrence of droughts. Bark beetle outbreaks transfer carbon from the live photosynthesizing pools to the dead respiring pool where carbon slowly decomposes into the atmosphere causing landscapes to change from a net sink to source of carbon. Previous studies have usually been conducted at small localized areas, focused only on one or two bark beetle types or encompass a single outbreak event. The literature largely ignores the influence of bark beetle mortality on carbon balance at both local and regional scales by focusing on multiple bark beetles types and events. This study uses a combination of the Carnegie Ames Stanford Approach (CASA) carbon cycle model driven by remotely sensed biophysical observations, Forest Inventory and Analysis (FIA) derived post-disturbance biomass regeneration trajectories, and mortality rates obtained from Aerial Detection Survey (ADS) insect outbreak polygons. The synthesis of the carbon cycle based modeling approach and different data products results in characteristic carbon trajectories for Net Ecosystem Productivity (NEP), Net Primary Productivity (NPP) and heterotrophic respiration associated with insect outbreaks. This study demonstrates that bark beetle events change landscapes from a sink to source of carbon at a local scale but at a larger regional level the influence of bark beetle outbreaks are not prominent compared to other disturbance agents.

  18. Assessment of carbon pools in production forest, Pahang, Malaysia

    Science.gov (United States)

    Azian, M.; Nizam, M. S.; Samsudin, M.; Ismail, P.

    2016-11-01

    Forest is one of the main sources of carbon stock. Forest plays a key role in sustainable management by providing different aspects of forest ecosystem such as source of timber products, provide of clean water, food sources, etc. A study was conducted to assess carbon pools in selected production forest of Pahang, Malaysia. There are five main types of carbon pools that are recognized available in the forest, i.e. aboveground biomass (AGB), belowground biomass (BGB), deadwood, litter and soil; that these components of carbon pools can accumulate and release carbon into the atmosphere. Five sites with different years of logging period representing status of the forest were selected (i.e. before logging (PU), immediate after logging (P0), after 10 (P10), 20 (P20) and 30 (P30) years of logging). Twenty plots of 0.25 ha (50 m × 50 m) each were established with a total sampling area of 1.0 ha at each site. All trees with ≥10 cm diameter at breast height (dbh) were tagged, identified and measured. Soil at 0-30 cm, litter and dead wood were sampled and collected in every each of sub-plots to determine and assess carbon stocks within sites. The results indicated that AGB carbon had highest portion of carbon compared to soil, BGB, deadwood and litter, which comprised about 63% of the total carbon pools. It was followed by soil and BGB that comprised about 22% and 13%, respectively. Deadwood and litter contributes the same percentage which is about 1%. In terms of status of the forest, AGB contained the highest carbon which is range from 110.49 tC ha-1 to 164.49 tC ha-1 compared with soil (33.72 tC ha-1 to 68.51 tC ha-1), BGB tC ha-1 to 34 tC ha-1), deadwood (1.57 tC ha-1 to 5.55 tC ha-1) and litter (1.42 tC ha-1 to 2.19 tC ha-1). Results from this study will be very helpful as baseline of carbon storage in different status of forest from before harvesting to logged-over forest and the impact of harvesting on the carbon stock in Pahang and Peninsular Malaysia as a whole.

  19. Carbon accounting of forest bioenergy: from model calibrations to policy options (Invited)

    Science.gov (United States)

    Lamers, P.

    2013-12-01

    Programs to stimulate biomass use for the production of heating/cooling and electricity have been implemented in many countries as part of their greenhouse gas emission reduction strategies. Critiques claim however that the use of forest biomass, e.g. as a replacement of hard-coal in large-scale power plants or mineral oil fuelled residential heating boilers, countervails carbon saving and thus also climate change mitigation strategies, at least in the short-term, as forest biomass combustion releases previously stored biogenic carbon back into the atmosphere. While there seems general agreement that carbon emitted from bioenergy combustion was and will again be sequestered from the atmosphere given a sustainable biomass management system, there is inherent concern that carbon release and sequestration rates may not be in temporal balance with each other and eventually jeopardize mid-century carbon/temperature/climate targets. So far, biomass carbon accounting systems (including those that are part of regulatory standards) have not incorporated this potential temporal imbalance or ';carbon debt'. The potential carbon debt caused by wood harvest and the resulting time spans needed to reach pre-harvest carbon levels (payback) or those of a reference case (parity) have become important parameters for climate and bioenergy policy developments. The present range of analyses however varies in assumptions, regional scopes, and conclusions. Policy makers are confronted with this portfolio while needing to address the temporal carbon aspect in current regulations. In order to define policies for our carbon constrained world, it is critical to better understand the dimensions and regional differences of these carbon cycles. This paper/presentation discusses to what extent and under which circumstances (i.e. bioenergy systems) a temporal forest carbon imbalance could jeopardize future temperature and eventually climate targets. It further reviews the current state of

  20. Higher subsoil carbon storage in species-rich than species-poor temperate forests

    Science.gov (United States)

    Schleuß, Per-Marten; Heitkamp, Felix; Leuschner, Christoph; Fender, Ann-Catrin; Jungkunst, Hermann F.

    2014-01-01

    Forest soils contribute ca. 70% to the global soil organic carbon (SOC) pool and thus are an important element of the global carbon cycle. Forests also harbour a large part of the global terrestrial biodiversity. It is not clear, however, whether tree species diversity affects SOC. By measuring the carbon concentration of different soil particle size fractions separately, we were able to distinguish between effects of fine particle content and tree species composition on the SOC pool in old-growth broad-leaved forest plots along a tree diversity gradient (1-, 3- and 5-species). Variation in clay content explained part of the observed SOC increase from monospecific to mixed forests, but we show that the carbon concentration per unit clay or fine silt in the subsoil was by 30-35% higher in mixed than monospecific stands indicating a significant species identity or species diversity effect on C stabilization. Underlying causes may be differences in fine root biomass and turnover, in leaf litter decomposition rate among the tree species, and/or species-specific rhizosphere effects on soil. Our findings may have important implications for forestry offering management options through preference of mixed stands that could increase forest SOC pools and mitigate climate warming.

  1. Current and potential carbon stocks in Moso bamboo forests in China.

    Science.gov (United States)

    Li, Pingheng; Zhou, Guomo; Du, Huaqiang; Lu, Dengsheng; Mo, Lufeng; Xu, Xiaojun; Shi, Yongjun; Zhou, Yufeng

    2015-06-01

    Bamboo forests provide important ecosystem services and play an important role in terrestrial carbon cycling. Of the approximately 500 bamboo species in China, Moso bamboo (Phyllostachys pubescens) is the most important one in terms of distribution, timber value, and other economic values. In this study, we estimated current and potential carbon stocks in China's Moso bamboo forests and in their products. The results showed that Moso bamboo forests in China stored about 611.15 ± 142.31 Tg C, 75% of which was in the top 60 cm soil, 22% in the biomass of Moso bamboos, and 3% in the ground layer (i.e., bamboo litter, shrub, and herb layers). Moso bamboo products store 10.19 ± 2.54 Tg C per year. The potential carbon stocks reach 1331.4 ± 325.1 Tg C, while the potential C stored in products is 29.22 ± 7.31 Tg C a(-1). Our results indicate that Moso bamboo forests and products play a critical role in C sequestration. The information gained in this study will facilitate policy decisions concerning carbon sequestration and management of Moso bamboo forests in China.

  2. Soil Organic Carbon Responses to Forest Expansion on Mountain Grasslands

    DEFF Research Database (Denmark)

    Guidi, Claudia

    Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties...... involved into long-term stability are largely unknown. The aim of this PhD thesis was to explore changes in: (i) SOC stocks; (ii) physical SOC fractions; and (iii) labile soil carbon components following forest expansion on mountain grasslands. A land-use gradient located in the Southern Alps (Italy....... Changes in labile soil C were assessed by carbohydrate and thermal analyses of soil samples and fractions. Forest expansion on mountain grasslands caused a decrease in SOC stocks within the mineral soil. The SOC accumulation within the organic layers following forest establishment could not fully...

  3. Organic carbon efflux from a deciduous forest catchment in Korea

    Directory of Open Access Journals (Sweden)

    S. J. Kim

    2010-04-01

    Full Text Available Soil infiltration and surface discharge of precipitation are critical processes that affect the efflux of Dissolved Organic Carbon (DOC and Particulate Organic Carbon (POC in forested catchments. Concentrations of DOC and POC can be very high in the soil surface in most forest ecosystems and their efflux may not be negligible particularly under the monsoon climate. In East Asia, however, there are little data available to evaluate the role of such processes in forest carbon budget. In this paper, we address two basic questions: (1 how does stream discharge respond to storm events in a forest catchment? and (2 how much DOC and POC are exported from the catchment particularly during the summer monsoon period? To answer these questions, we collected hydrological data (e.g., precipitation, soil moisture, runoff discharge, groundwater level and conducted hydrochemical analyses (including DOC, POC, and six tracers in a deciduous forest catchment in Gwangneung National Arboretum in west-central Korea. Based on the end-member mixing analysis of the six storm events during the summer monsoon in 2005, the surface discharge was estimated as 30 to 80% of the total runoff discharge. The stream discharge responded to precipitation within 12 h during these storm events. The annual efflux of DOC and POC from the catchment was estimated as 0.04 and 0.05 t C ha−1 yr−1, respectively. Approximately 70% of the annual organic carbon efflux occurred during the summer monsoon period. Overall, the annual efflux of organic carbon was estimated to be about 10% of the Net Ecosystem carbon Exchange (NEE obtained by eddy covariance measurement at the same site. Considering the current trends of increasing intensity and amount of summer rainfall and the large interannual variability in NEE, ignoring the organic carbon efflux from forest catchments would result in an inaccurate estimation of the carbon sink strength of forest ecosystems in the monsoon

  4. Towards a quantitative understanding of the late Neoproterozoic carbon cycle

    DEFF Research Database (Denmark)

    Bjerrum, Christian Jannik; Canfield, Donald Eugene

    2011-01-01

    The cycles of carbon and oxygen at the Earth surface are intimately linked, where the burial of organic carbon into sediments represents a source of oxygen to the surface environment. This coupling is typically quantified through the isotope records of organic and inorganic carbon. Yet, the late...... Neoproterozoic Eon, the time when animals first evolved, experienced wild isotope fluctuations which do not conform to our normal understanding of the carbon cycle and carbon-oxygen coupling. We interpret these fluctuations with a new carbon cycle model and demonstrate that all of the main features...... of the carbonate and organic carbon isotope record can be explained by the release of methane hydrates from an anoxic dissolved organic carbon-rich ocean into an atmosphere containing oxygen levels considerably less than today....

  5. Towards a quantitative understanding of the late Neoproterozoic carbon cycle

    DEFF Research Database (Denmark)

    Bjerrum, Christian J.; Canfield, Donald Eugene

    2011-01-01

    The cycles of carbon and oxygen at the Earth surface are intimately linked, where the burial of organic carbon into sediments represents a source of oxygen to the surface environment. This coupling is typically quantified through the isotope records of organic and inorganic carbon. Yet, the late...... Neoproterozoic Eon, the time when animals first evolved, experienced wild isotope fluctuations which do not conform to our normal understanding of the carbon cycle and carbon-oxygen coupling. We interpret these fluctuations with a new carbon cycle model and demonstrate that all of the main features...... of the carbonate and organic carbon isotope record can be explained by the release of methane hydrates from an anoxic dissolved organic carbon-rich ocean into an atmosphere containing oxygen levels considerably less than today....

  6. Estimation of the carbon storage of forest vegetation and carbon emission from forest fires in Heilongjiang Province, China

    Institute of Scientific and Technical Information of China (English)

    HU Hai-qing; LIU Yuan-chun; JIAO Yan

    2007-01-01

    The forest resource of Heilongjiang province has important position in china. On the basis of the six times of national forest inventory data (1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003) surveyed by the Forestry Ministry of P. R. China from 1973 to 2003, the carbon storage of forests in Heilongjiang Province are estimated by using the method of linear relationship of each tree species between biomass and volume. The results show that the carbon storage of Heilongjiang forests in the six periods (1973-1976,1977-1981, 1985-1988, 1989-1993, 1994-1998, 1999-2003) are 7.164×108 t, 4.871×108 t, 5.094×108 t, 5.292×108 t, 5.594×108 t and 5.410×108 t, respectively., which showed a trend of decreasing in early time and then increasing. It indicated that Heilongjiang forests play an important role as a sink of atmospheric carbon dioxide during past 30 years. Based on the data of forest fires from 1980 to 1999 and ground biomass estimation for some forest types in Heilongjiang Province, it is estimated that the amount of mean annual consumed biomass of forests is 391758.65t-522344.95t, accounting for 6.4%-8.4% of total national consummation from forest fires, and the amount of carbon emission is 176 291.39t-235 055.23t, about 8% of total national emission from forest fires. The emission of CO2, CO, CH4 and NMHC from forest fires in Heilongjiang Province are estimated at 581761.6-775682.25 t, 34892.275-46523.04 t, 14091.11-18788.15 t and 6500-9000 t, respectively, every year.

  7. [Regional and global estimates of carbon stocks and carbon sequestration capacity in forest ecosystems: A review].

    Science.gov (United States)

    Liu, Wei-wei; Wang, Xiao-ke; Lu, Fei; Ouyang, Zhi-yun

    2015-09-01

    As a dominant part of terrestrial ecosystems, forest ecosystem plays an important role in absorbing atmospheric CO2 and global climate change mitigation. From the aspects of zonal climate and geographical distribution, the present carbon stocks and carbon sequestration capacity of forest ecosystem were comprehensively examined based on the review of the latest literatures. The influences of land use change on forest carbon sequestration were analyzed, and factors that leading to the uncertainty of carbon sequestration assessment in forest ecosystem were also discussed. It was estimated that the current forest carbon stock was in the range of 652 to 927 Pg C and the carbon sequestration capacity was approximately 4.02 Pg C · a(-1). In terms of zonal climate, the carbon stock and carbon sequestration capacity of tropical forest were the maximum, about 471 Pg C and 1.02-1.3 Pg C · a(-1) respectively; then the carbon stock of boreal forest was about 272 Pg C, while its carbon sequestration capacity was the minimum, approximately 0.5 Pg C · a(-1); for temperate forest, the carbon stock was minimal, around 113 to 159 Pg C and its carbon sequestration capacity was 0.8 Pg C · a(-1). From the aspect of geographical distribution, the carbon stock of forest ecosystem in South America was the largest (187.7-290 Pg C), then followed by European (162.6 Pg C), North America (106.7 Pg C), Africa (98.2 Pg C) and Asia (74.5 Pg C), and Oceania (21.7 Pg C). In addition, carbon sequestration capacity of regional forest ecosystem was summed up as listed below: Tropical South America forest was the maximum (1276 Tg C · a(-1)), then were Tropical Africa (753 Tg C · a(-1)), North America (248 Tg C · a(-1)) and European (239 Tg C · a(-1)), and East Asia (98.8-136.5 Tg C · a(-1)) was minimum. To further reduce the uncertainty in the estimations of the carbon stock and carbon sequestration capacity of forest ecosystem, comprehensive application of long-term observation, inventories

  8. Modelling nutrient cycling in forest ecosystems; Modellering av naeringssyklus i skogoekosystemer

    Energy Technology Data Exchange (ETDEWEB)

    Kvindesland, Sheila H.S.B.

    1997-12-31

    Acid deposition`s threat to fresh water and forest environments became an issue in the late 1960s. Acid deposition and forest nutrient cycling then began to be researched in greater co-operation. This thesis studies nutrient cycling processes in Norway spruce forests, emphasizing the effects on soil chemical properties, soil solution chemistry and streamwater chemistry. It investigates the effects of different aged stands on nutrient cycling and sets up nutrient budgets of the base cations and nitrogen at two sites in Norway. It also selects, documents, calibrates, tests and improves nutrient cycling models for use in Norwegian forests. 84 refs., 44 figs., 46 tabs.

  9. A meta-analysis on forest bioenergy carbon greenhouse gas accounting

    Science.gov (United States)

    Buchholz, T.

    2013-12-01

    Many recent comprehensive biogenic GHG emissions studies of forest biomass energy systems relative to fossil fuel energy system have been published in the peer reviewed and gray literature challenging the assumption of the immediate carbon neutrality of biomass energy. We conducted a quantitative meta-analysis of these studies to document common assumptions and conclusions related to the atmospheric benefits of switching from fossil fuels to forest-based woody biomass energy. We summarized the temporal component of lifecycle GHG emissions and sequestration for bioenergy systems. The analytical matrix included elements such as: Baseline Definition, Energy Type Considered (fossil and biomass), Life Cycle Boundary Definition, Carbon Pools Considered, Regional Differences, Forest Management Practices, and Land Use Change.

  10. Beyond the Calvin Cycle: Autotrophic Carbon Fixation in the Ocean

    Science.gov (United States)

    Hügler, Michael; Sievert, Stefan M.

    2011-01-01

    Organisms capable of autotrophic metabolism assimilate inorganic carbon into organic carbon. They form an integral part of ecosystems by making an otherwise unavailable form of carbon available to other organisms, a central component of the global carbon cycle. For many years, the doctrine prevailed that the Calvin-Benson-Bassham (CBB) cycle is the only biochemical autotrophic CO2 fixation pathway of significance in the ocean. However, ecological, biochemical, and genomic studies carried out over the last decade have not only elucidated new pathways but also shown that autotrophic carbon fixation via pathways other than the CBB cycle can be significant. This has ramifications for our understanding of the carbon cycle and energy flow in the ocean. Here, we review the recent discoveries in the field of autotrophic carbon fixation, including the biochemistry and evolution of the different pathways, as well as their ecological relevance in various oceanic ecosystems.

  11. Forest carbon stocks and fluxes in physiographic zones of India

    Directory of Open Access Journals (Sweden)

    Sheikh Mehraj A

    2011-12-01

    Full Text Available Abstract Background Reducing carbon Emissions from Deforestation and Degradation (REDD+ is of central importance to combat climate change. Foremost among the challenges is quantifying nation's carbon emissions from deforestation and degradation, which requires information on forest carbon storage. Here we estimated carbon storage in India's forest biomass for the years 2003, 2005 and 2007 and the net flux caused by deforestation and degradation, between two assessment periods i.e., Assessment Period first (ASP I, 2003-2005 and Assessment Period second (ASP II, 2005-2007. Results The total estimated carbon stock in India's forest biomass varied from 3325 to 3161 Mt during the years 2003 to 2007 respectively. There was a net flux of 372 Mt of CO2 in ASP I and 288 Mt of CO2 in ASP II, with an annual emission of 186 and 114 Mt of CO2 respectively. The carbon stock in India's forest biomass decreased continuously from 2003 onwards, despite slight increase in forest cover. The rate of carbon loss from the forest biomass in ASP II has dropped by 38.27% compared to ASP I. Conclusion With the Copenhagen Accord, India along with other BASIC countries China, Brazil and South Africa is voluntarily going to cut emissions. India will voluntary reduce the emission intensity of its GDP by 20-25% by 2020 in comparison to 2005 level, activities like REDD+ can provide a relatively cost-effective way of offsetting emissions, either by increasing the removals of greenhouse gases from the atmosphere by afforestation programmes, managing forests, or by reducing emissions through deforestation and degradation.

  12. Biochar and biological carbon cycling in temperate soils

    Science.gov (United States)

    McCormack, S. A.; Vanbergen, A. J.; Bardgett, R. D.; Hopkins, D. W.; Ostle, N.

    2012-04-01

    Production of biochar, the recalcitrant residue formed by pyrolysis of plant matter, is suggested as a means of increasing storage of stable carbon (C) in the soil (1). Biochar has also been shown to act as a soil conditioner, increasing the productivity of certain crops by reducing nutrient leaching and improving soil water-holding capacity. However, the response of soil carbon pools to biochar addition is not yet well understood. Studies have shown that biochar has highly variable effects on microbial C cycling and thus on soil C storage (2,3,4). This discrepancy may be partially explained by the response of soil invertebrates, which occupy higher trophic levels and regulate microbial activity. This research aims to understand the role of soil invertebrates (i.e. Collembola and nematode worms) in biochar-mediated changes to soil C dynamics across a range of plant-soil communities. An open-air, pot-based mesocosm experiment was established in May, 2011 at the Centre for Ecology and Hydrology, Edinburgh. Three treatments were included in a fully-factorial design: biochar (presence [2 % w/w] or absence), soil type (arable sandy, arable sandy loam, grassland sandy loam), and vegetation type (Hordeum vulgare, Lolium perenne, unvegetated). Monitored parameters include: invertebrate and microbial species composition, soil C fluxes (CO2 and trace gas evolution, leachate C content, primary productivity and soil C content), and soil conditions (pH, moisture content and water-holding capacity). Preliminary results indicate that biochar-induced changes to soil invertebrate communities and processes are affected by pre-existing soil characteristics, and that soil texture in particular may be an important determinant of soil response to biochar addition. 1. Lehmann, 2007. A handful of carbon. Nature 447, 143-144. 2. Liang et al., 2010. Black carbon affects the cycling of non-black carbon in soil. Organic Geochemistry 41, 206-213. 3. Van Zwieten et al., 2010. Influence of

  13. Effect of land use change on the carbon cycle in Amazon soils

    Science.gov (United States)

    Trumbore, Susan E.; Davidson, Eric A.

    1994-01-01

    The overall goal of this study was to provide a quantitative understanding of the cycling of carbon in the soils associated with deep-rooting Amazon forests. In particular, we wished to apply the understanding gained by answering two questions: (1) what changes will accompany the major land use change in this region, the conversion of forest to pasture? and (2) what is the role of carbon stored deeper than one meter in depth in these soils? To construct carbon budgets for pasture and forest soils we combined the following: measurements of carbon stocks in above-ground vegetation, root biomass, detritus, and soil organic matter; rates of carbon inputs to soil and detrital layers using litterfall collection and sequential coring to estimate fine root turnover; C-14 analyses of fractionated SOM and soil CO2 to estimate residence times; C-13 analyses to estimate C inputs to pasture soils from C-4 grasses; soil pCO2, volumetric water content, and radon gradients to estimate CO2 production as a function of soil depth; soil respiration to estimate total C outputs; and a model of soil C dynamics that defines SOM fractions cycling on annual, decadal, and millennial time scales.

  14. Priming alters soil carbon dynamics during forest succession

    Science.gov (United States)

    Qiao, Na; Xu, Xingliang; Wang, Juan; Kuzyakov, Yakov

    2017-04-01

    The mechanisms underlying soil carbon (C) dynamics during forest succession remain challenged. We examined priming of soil organic matter (SOM) decomposition along a vegetation succession: grassland, young and old-growth forests. Soil C was primed much more strongly in young secondary forest than in grassland or old-growth forest. Priming resulted in large C losses (negative net C balance) in young-forest soil, whereas C stocks increased in grassland and old-growth forest. Microbial composition assessed by phospholipid fatty acids (PLFA) and utilization of easily available organics (13C-PLFA) indicate that fungi were responsible for priming in young-forest soils. Consequently, labile C inputs released by litter decomposition and root exudation determine microbial functional groups that decompose SOM during forest succession. These findings provide novel insights into connections between SOM dynamics and stabilization with microbial functioning during forest succession and show that priming is an important mechanism for contrasting soil C dynamics in young and old-growth forests.

  15. Land Use and Land Cover Change in Forest Frontiers: The Role of Household Life Cycles

    Science.gov (United States)

    Walker, Robert

    2002-01-01

    Tropical deforestation remains a critical issue given its present rate and a widespread consensus regarding its implications for the global carbon cycle and biodiversity. Nowhere is the problem more pronounced than in the Amazon basin, home to the world's largest intact, tropical forest. This article addresses land cover change processes at household level in the Amazon basin, and to this end adapts a concept of domestic life cycle to the current institutional environment of tropical frontiers. In particular, it poses a risk minimization model that integrates demography with market-based factors such as transportation costs and accessibility. In essence, the article merges the theory of Chayanov with the household economy framework, in which markets exist for inputs (including labor), outputs, and capital. The risk model is specified and estimated, using survey data for 261 small producers along the Transamazon Highway in the eastern sector of the Brazilian Amazon.

  16. Land Use and Land Cover Change in Forest Frontiers: The Role of Household Life Cycles

    Science.gov (United States)

    Walker, Robert

    2002-01-01

    Tropical deforestation remains a critical issue given its present rate and a widespread consensus regarding its implications for the global carbon cycle and biodiversity. Nowhere is the problem more pronounced than in the Amazon basin, home to the world's largest intact, tropical forest. This article addresses land cover change processes at household level in the Amazon basin, and to this end adapts a concept of domestic life cycle to the current institutional environment of tropical frontiers. In particular, it poses a risk minimization model that integrates demography with market-based factors such as transportation costs and accessibility. In essence, the article merges the theory of Chayanov with the household economy framework, in which markets exist for inputs (including labor), outputs, and capital. The risk model is specified and estimated, using survey data for 261 small producers along the Transamazon Highway in the eastern sector of the Brazilian Amazon.

  17. Economics of forest and forest carbon projects. Translating lessons learned into national REDD+ implementation

    Energy Technology Data Exchange (ETDEWEB)

    Zaballa Romero, M.; Traerup, S.; Wieben, E.; Ravnkilde Moeller, L.; Koch, A.

    2013-01-15

    The financial implications of implementing a new forest management paradigm have not been well understood and have often been underestimated. Resource needs for e.g., stakeholder consultation, capacity building and addressing the political economy are seldom fully accounted for in the resource needs estimates put forward in connection to REDD+. This report investigates the economics of implementing forest and REDD+ projects through eight case studies from Africa, Latin America and Asia, analyzing real forest and REDD+ investments. The report is part of efforts to share financial experiences and lessons learned with policymakers, project developers and stakeholders, with the objective to inform forest project and strategy development. It presents experiences and advice on the risks, costs and revenues of forest projects, thereby informing not only the development of future REDD+ initiatives but also the testing of advanced market commitments as a finance option for sustainable forest management. The findings in the report underline the fact that only through sound and transparent financial information will forest projects and national forest initiatives become interesting for private financial institutions and comparable with other investment opportunities. It is therefore important to include robust analysis of the operations business case and its financial attractiveness to commercial investors, early in the design process. As for the economics of forest and forest carbon projects, it appears that REDD+ payments alone, especially at current prices, will not deliver the revenues that cover all expenses of transparent and long-term mitigation of forest carbon emissions. Instead the findings underline the importance of building up forest operations which effectively manages risk and delivers several revenue streams. These findings are aligned with the advocacy efforts of UNEP and the UN-REDD Programme on multiple benefits and the combination of various funding and

  18. Legacies of an ice storm on the long-term carbon exchange of a temperate forest

    Science.gov (United States)

    Dunn, A. L.; Morgan, K.

    2010-12-01

    Atmosphere-biosphere exchange of carbon is governed by processes operating on a variety of timescales, from diurnal to seasonal to decadal and beyond. Disturbance events, such as fire, insect outbreaks, and ice storms, are infrequent but exert an impact on atmosphere-biosphere exchanges that may persist for many years. Quantification of the role of these biophysical pulses on carbon exchange is therefore critical to accurately model the global carbon cycle. In this study, we investigate the long-term effect of an ice storm on forest-atmosphere carbon exchange. In December 2008, an ice storm affected Harvard Forest, a temperate forest located in north-central Massachusetts. As a result of this ice storm, tree mortality rates were elevated above the background mortality rate of 0.6 Mg C ha-1 yr-1 measured by Barford et al. (2001). Mortality rates in the year of the ice storm in the study area ranged from 1.1 Mg C ha-1 yr-1 in a 19-year-old forest stand to 8.7 Mg C ha-1 yr-1 in an 84-year-old red pine plantation. The woody debris generated by this disturbance event represented a significant increase in the pool of respirable aboveground carbon. The woody debris respiration model of Liu et al (2006) is used to estimate the legacy of this disturbance event on fluxes of carbon to the atmosphere in future years. Results from this study have implications for modeling carbon cycle response to infrequent, large-scale disturbance events.

  19. Carbon cycle: Global warming then and now

    Science.gov (United States)

    Stassen, Peter

    2016-04-01

    A rapid warming event 55.8 million years ago was caused by extensive carbon emissions. The rate of change of carbon and oxygen isotopes in marine shelf sediments suggests that carbon emission rates were much slower than anthropogenic emissions.

  20. A New U.S. Carbon Cycle Science Plan

    Science.gov (United States)

    Michalak, A. M.; Jackson, R.; Marland, G.; Sabine, C.

    2009-05-01

    The report "A U.S. carbon cycle science plan" (J. L. Sarmiento and S. C. Wofsy, U.S. Global Change Res. Program, Washington, D. C., 1999) outlined research priorities and promoted coordinated carbon cycle research across federal agencies in the United States for nearly a decade. Building on this framework and subsequent reports (http://www.carboncyclescience.gov/docs.php), a working group comprised of 27 scientists was formed in 2008 under the United States Carbon Cycle Science Program to review the 1999 Science Plan, and to develop an updated strategy for carbon cycle research for the period from 2010 to 2020. This comprehensive review is being conducted with wide input from the research and stakeholder communities. The recommendations of the Carbon Cycle Science Working Group (CCSWG) will go to U.S. agency managers who have collective responsibility for setting national carbon cycle science priorities and for sponsoring much of the carbon cycle research in the United States. This presentation will provide an update on the ongoing planning process, will outline the steps that the CCSWG is undertaking in building consensus towards an updated U.S. Carbon Cycle Science Plan, and will seek input on the best ways in which to coordinate efforts with ongoing and upcoming research in Canada and Mexico, as well as with ongoing work globally.

  1. Grass invasion effects on forest soil carbon depend on landscape-level land use patterns.

    Science.gov (United States)

    Craig, Matthew E; Pearson, Scott M; Fraterrigo, Jennifer M

    2015-08-01

    Plant invasions can alter the quality and quantity of detrital and root-derived inputs entering a system, thereby influencing the activities of microbial decomposers and affecting the soil carbon cycle. The effect of these inputs on soil carbon storage is often conflicting, suggesting strong context dependency in the plant-decomposer relationship. Whether there is a generalizable pattern that explains this dependency remains relatively unexplored. Here, we (1) examine how invasion by the exotic grass Microstegium vimineum affects carbon cycling across a land use gradient, and (2) evaluate the importance of inorganic nitrogen availability and other environmental variables for explaining patterns in soil carbon. Using paired invaded and uninvaded plots, we quantified invasion effects on belowground carbon pools, extracellular enzyme activities, and native leaf litter decomposition in forests embedded in an urban, agricultural, or forested landscape matrix. Compared to the urban matrix, invasion-associated declines in total soil organic carbon in the forested and agricultural landscapes were 3.5 and 2.5 times greater, respectively. Inorganic nitrogen availability and M. vimineum biomass interacted to explain these patterns: when both nitrogen availability and M. vimineum biomass were high, invaded soils exhibited higher total organic carbon, unchanged particulate organic matter carbon, and higher mineral-associated organic matter carbon compared to adjacent uninvaded soils. Consistent with these patterns, activities of carbon-mineralizing enzymes were lower in invaded than in uninvaded soils when both nitrogen availability and M. vimineum biomass were high. By contrast,. decomposition of native leaf litter was faster when inorganic nitrogen availability and M. vimineum biomass were high. Our findings suggest that, although this invader may accelerate carbon cycling in forest soils, its effects on soil carbon storage largely depend on nitrogen availability and invader

  2. Subsurface Carbon Cycling Below the Root Zone

    Science.gov (United States)

    Wan, J.; Dong, W.; Kim, Y.; Tokunaga, T. K.; Bill, M.; Conrad, M. E.; Williams, K. H.; Long, P. E.; Hubbard, S. S.

    2014-12-01

    Carbon in the subsurface below the root zone is an important yet poorly understood link in the terrestrial C cycle, interfacing between overlying soil and downstream aquatic systems. Thus, the nature and behavior of C in the vadose zone and groundwater, particularly the dynamics of mobile dissolved and suspended aqueous species, need to be understood for predicting C cycling and responses to climate change. This study is designed to understand the C balance (influxes, effluxes, and sequestration) and mechanisms controlling subsurface organic and inorganic C transport and transformation. Our initial investigations are being conducted at the Rifle Site floodplain along the Colorado River, in Colorado (USA). Within this floodplain, sediment samples were collected and sampling/monitoring instruments were installed down to 7 m depth at three sites. Pore water and gas samplers at 0.5 m depth intervals within the ~3.5 m deep vadose zone, and multilevel aquifer samplers have yielded depth- and time-resolved profiles of dissolved and suspended organic and inorganic C, and CO2 for over 1.5 years. Analyses conducted to determine seasonally and vertically resolved geochemical profiles show that dissolved organic matter (DOM) characteristics vary among three distinct hydrobiogeochemical zones; the vadose zone, capillary fringe, and saturated zone. The concentrations of dissolved organic matter (DOM) are many times higher in the vadose zone and the capillary fringe than in groundwater, and vary seasonally. The DOM speciation, aqueous geochemistry, solid phase analyses, and d13C isotope data show the importance of both biotic and abiotic C transformations during transport through the vertical gradients of moisture and temperature. In addition to DOM, suspended organic C and bacteria have been collected from samplers within the capillary fringe. Based on the field-based findings, long-term laboratory column experiments are being conducted under simulated field moisture

  3. Organic carbon stock in some forest soils in Serbia

    OpenAIRE

    Kadovic Ratko; Belanovic Snežana; Kneževic Milan; Danilovic Milorad; Košanin Olivera; Beloica Jelena

    2012-01-01

    The content of organic carbon (C) was researched in topsoil layers (0-20 cm) in the most represented soils of forest ecosystems in central Serbia: eutric ranker, eutric cambisol and dystric cambisol. The soils were sampled during 2003, 2004 and 2010. Laboratory analyses included the soil physical and chemical properties necessary for the quantification of the soil organic carbon in organic and mineral layers. Mean values of the soil organic carbon (SOC) sto...

  4. Effectiveness of management interventions on forest carbon stock in planted forests in Nepal.

    Science.gov (United States)

    Dangal, Shambhu Prasad; Das, Abhoy Kumar; Paudel, Shyam Krishna

    2017-07-01

    Nepal has successfully established more than 370,000 ha of plantations, mostly with Pinus patula, in the last three and a half decades. However, intensive management of these planted forests is very limited. Despite the fact that the Kyoto Convention in 1997 recognized the role of plantations for forest-carbon sequestration, there is still limited knowledge on the effects of management practices and stand density on carbon-sequestration of popular plantation species (i.e. Pinus patula) in Nepal. We carried out case studies in four community forests planted between 1976 and 1990 to assess the impacts of management on forest carbon stocks. The study found that the average carbon stock in the pine plantations was 217 Mg C ha(-1), and was lower in forests with intensively managed plantations (214.3 Mg C ha(-1)) than in traditionally managed plantations (219 Mg C ha(-1)). However, it was the reverse in case of soil carbon, which was higher (78.65 Mg C ha(-1)) in the forests with intensive management. Though stand density was positively correlated with carbon stock, the proportionate increment in carbon stock was lower with increasing stand density, as carbon stock increased by less than 25% with a doubling of stand density (300-600). The total carbon stock was higher in plantations aged between 25 and 30 years compared to those aged between 30 and 35 years. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. The Lifestyle Carbon Dividend: Assessment of the Carbon Sequestration Potential of Grasslands and Pasturelands Reverted to Native Forests

    Science.gov (United States)

    Rao, S.; Jain, A. K.; Shu, S.

    2015-12-01

    What is the potential of a global transition to a vegan lifestyle to sequester carbon and mitigate climate change? To answer this question, we use an Earth System Model (ESM), the Integrated Science Assessment Model (ISAM). ISAM is a fully coupled biogeochemistry (carbon and nitrogen cycles) and biogeophysics (hydrology and thermal energy) ESM, which calculates carbon sources and sinks due to land cover and land use change activities, such as reforestation and afforestation. We calculate the carbon sequestration potential of grasslands and pasturelands that can be reverted to native forests as 265 GtC on 1.96E+7 km2 of land area, just 41% of the total area of such lands on Earth. The grasslands and pasturelands are assumed to revert back to native forests which existed prior to any human intervention and these include tropical, temperate and boreal forests. The results are validated with above ground regrowth measurements. Since this carbon sequestration potential is greater than the 240 GtC of that has been added to the atmosphere since the industrial era began, it shows that such global lifestyle transitions have tremendous potential to mitigate and even reverse climate change.

  6. Development of Low-carbon Forest Tourism with Emphasis on Construction of Urban Forest Park

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper mainly points out that the urban forest tourism has so many advantages and it will hopefully become the support industry of low-carbon forestry, and the development of urban forestparks in low-carbon economy is extraordinarily important, especially when faced with some serious traditional problems. A series of proposals about revolutionary measures are put forwards.

  7. Forest biodiversity, carbon and other ecosystem services: relationships and impacts of deforestation and forest degradation

    Science.gov (United States)

    Ian D. Thompson; Joice Ferreira; Toby Gardner; Manuel Guariguata; Lian Pin Koh; Kimiko Okabe; Yude Pan; Christine B. Schmitt; Jason Tylianakis; Jos Barlow; Valerie Kapos; Werner A. Kurz; John A. Parrotta; Mark D. Spalding; Nathalie. van Vliet

    2012-01-01

    REDD+ actions should be based on the best science and on the understanding that forests can provide more than a repository for carbon but also offer a wide range of services beneficial to people. Biodiversity underpins many ecosystem services, one of which is carbon sequestration, and individual species’ functional traits play an important role in determining...

  8. Carbon Sequestration Potential in Aboveground Biomass of Hybrid Eucalyptus Plantation Forest

    Directory of Open Access Journals (Sweden)

    Siti Latifah

    2013-04-01

    Full Text Available Forests are a significant part of the global carbon cycle. Forests sequester carbon by conducting photosynthesis, which is the process of converting light energy to chemical energy and storing it in the chemical bonds of sugar. Carbon sequestration through forestry has the potential to play a significant role in ameliorating global environmental problems such as atmospheric accumulation of GHG's and climate change.  The present investigation was carried out to determine carbon sequestration potential of hybrid Eucalyptus. This study was conducted primarily to develop a prediction model of carbon storage capacity for plantation forest of hybrid Eucalyptus in Aek Nauli, Simalungun District, North Sumatera. Models were tested and assessed for statistical validity and accuracy in predicting biomass and carbon, based on determination coefficient (R and correlation coefficient (r, aggregative deviation percentage (AgD, and the average deviation percentage (AvD. The best general model to estimate the biomass of hybrid Eucalyptus was Y = 1351,09x^0,876. e^(0,094.  Results showed that hybrid Eucalyptus had an average above-ground biomass in year 0 (the land without the eucalyptus trees up to year 3 as large as 1.36, 11.56, 43.18, and 63.84 t ha. The carbon content of hybrid Eucalyptus were 0.61, 5.2, 19.43 t^(-1, and 28,73  t^(-1 C ha while the carbon sequestration potential were 2.23, 19.08, 71.31, and 105.43 t^(-1 CO  ha^(-1 respectively.Keywords: biomass, carbon stock, model, hybrid Eucalyptus, plantation forest

  9. Biomass burning in boreal forests and peatlands: Effects on ecosystem carbon losses and soil carbon stabilization as black carbon

    Science.gov (United States)

    Turetsky, M. R.; Kane, E. S.; Benscoter, B.

    2011-12-01

    Climate change has increased both annual area burned and the severity of biomass combustion in some boreal regions. For example, there has been a four-fold increase in late season fires in boreal Alaska over the last decade relative to the previous 50 years. Such changes in the fire regime are expected to stimulate ecosystem carbon losses through fuel combustion, reduced primary production, and increased decomposition. However, biomass burning also will influence the accumulation of black carbon in soils, which could promote long-term soil carbon sequestration. Variations in slope and aspect regulate soil temperatures and drainage conditions, and affect the development of permafrost and thick peat layers. Wet soil conditions in peatlands and permafrost forests often inhibit combustion during wildfires, leading to strong positive correlations between pre- and post- fire organic soil thickness that persist through multiple fire cycles. However, burning can occur in poorly drained ecosystems through smouldering combustion, which has implications for emission ratios of CO2:CH4:CO as well as black carbon formation. Our studies of combustion severity and black carbon concentrations in boreal soils show a negative relationship between concentrations of black carbon and organic carbon in soils post-fire. Relative to well drained stands, poorly drained sites with thick peat layers (such as north-facing stands) had less severe burning and low concentrations of black carbon in mineral soils post-fire. Conversely, drier forests lost a greater proportion of their organic soils during combustion but retained larger black carbon stocks following burning. Overall, we have quantified greater black carbon concentrations in surface mineral soil horizons than in organic soil horizons. This is surprising given that wildfires typically do not consume the entire organic soil layer in boreal forests, and could be indicative of the vulnerability of black carbon formed in organic horizons

  10. Widespread Tree Mortality from the 2011 Texas Drought: Consequences for Forest Structure and Carbon Stocks

    Science.gov (United States)

    Moore, G. W.; Edgar, C.; Vogel, J. G.; Washington-Allen, R. A.; March, R.; Zehnder, R.

    2013-12-01

    Larger and more frequent drought-related tree mortality events can alter the carbon cycling of terrestrial ecosystems; however, the carbon cycling implications of drought in forest ecosystems is poorly understood because the effects are not discrete in time, tree species have varying survival tolerances, and tree mortality from drought is often diffusely distributed across the landscape masking its effect from satellite observation. Widespread tree mortality was caused by the exceptional 2011 drought in Texas. In the summer following the drought, we used a statewide survey of 599 plots and satellite imagery (pre/post drought) to estimate the impact of the 2011 Texas Drought on forest C storage and cycling. In each 0.16 ha plot, dead trees were identified to the genus level and diameters were recorded. Normalized Difference Vegetation Index (ΔNDVI = May 2012 NDVI - May 2011 NDVI) derived from the MODIS satellite sensor was calibrated to the field plots to produce a 2011 tree mortality map for Texas. We estimate that 301 million trees died in Texas from the exceptional drought of 2011 (6.2% of live trees), which resulted in a conversion of 24-30 Tg C from live to dead tree carbon pools. This event was notable in that it affected a wide assemblage of species throughout the state across distinct ecoregions. The largest trees experienced disproportionately higher mortality; large angiosperms from historically wetter regions suffered the greatest losses. Gymnosperms thought to be drought-hardy also experienced unexpectedly high levels of mortality, with significant regional variation in whether the mortality was concentrated in large trees. The concentration of mortality in large trees likely had a disproportionate effect on forest net primary productivity, which is a key constraint on estimating the full effect of this drought on future forest C capture. In an effort toward full accounting of this event, we modeled its cumulative effects on regional C cycling and

  11. Mechanisms of below-ground carbon cycling in subarctic ecosystems

    Energy Technology Data Exchange (ETDEWEB)

    Olsrud, Maria

    2004-10-01

    Some components of the below-ground carbon cycle in terrestrial ecosystems are still poorly understood. A better understanding will be necessary to predict adequately the impacts of global change factors on C cycling and storage, especially in high-latitude ecosystems, where much of the C is stored below-ground. In this work some of the mechanisms of the below-ground C cycle in subarctic ecosystems were studied and responses to present and potential future environmental conditions assessed. Using {sup 14}C pulse-labelling, C allocation to above-ground biomass, rhizomes, coarse roots, fine roots, hair roots, ericoid mycorrhizas, microbes and dissolved organic C (DOC) was determined repeatedly over the growing season in four of the most common vegetation types of the Scandinavian subarctic: (1) Dry dwarf shrub tundra; (2) Semi-wet mire; (3) Wet mire; and (4) the understorey of subarctic birch forest. Effects of increased temperatures, increased atmospheric CO{sub 2} concentrations and both factors in combination on below-ground C allocation, ericoid mycorrhizal colonisation and functioning were studied in an full-factorial open-top chamber experiment. Furthermore, responses of ericoid mycorrhizal colonisation rates to environmental variation during the growing season were investigated. Ecosystem C partitioning varied temporally in all studied ecosystems, possibly indicating changes in growth, nutrient uptake or C storage by vegetation. The relative importance of C pools with 'fast' versus 'slow' turnover rates varied spatially, among vegetation types. Therefore it is important for global change studies to consider the possible effects of vegetation changes on ecosystem C dynamics. Allocation of recent assimilates to fast-turnover C pools such as hair roots and DOC was particularly high in a dwarf shrub tundra making them quantitatively interesting pools to consider in studies of ecosystem C dynamics. Furthermore, a significant proportion of

  12. Scenario analysis of the impacts of forest management and climate change on the European forest sector carbon budget

    NARCIS (Netherlands)

    Karjalainen, T.; Pusinen, A.; Liski, J.; Nabuurs, G.J.; Eggers, T.; Lapveteläinen, T.; Kaipainen, T.

    2003-01-01

    Analysis of the impacts of forest management and climate change on the European forest sector carbon budget between 1990 and 2050 are presented in this article. Forest inventory based carbon budgeting with large scale scenario modelling was used. Altogether 27 countries and 128.5 million hectare of

  13. Final Technical Report Interannual Variations in the Rate of Carbon Storage by a Mid-Latitude Forest

    Energy Technology Data Exchange (ETDEWEB)

    Wofsy, Steven; Munger, J W

    2012-07-31

    The time series of Net Ecosystem Exchange (NEE) of carbon by an entire forest ecosystem on time scales from hourly to decadal was measured by eddy-covariance supplemented with plot-level measurements of biomass and tree demography. The results demonstrate the response of forest carbon fluxes and long-term budgets to climatic factors and to successional change. The data from this project have been extensively used worldwide by the carbon cycle science community in support of model development and validation of remote sensing observations.

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

    Science.gov (United States)

    Ahmad Dar, Javid; Somaiah, Sundarapandian

    2015-02-01

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

  15. Element cycling in forest soils - modelling the effects of a changing environment

    Energy Technology Data Exchange (ETDEWEB)

    Walse, C.

    1998-11-01

    Element cycling and nutrient supply in forest ecosystems are of vital importance for short-term productivity and for longer-term land management in terms of nutrient leaching and CO{sub 2} fixation. This thesis includes a series of studies with the objective of modelling some aspects of the effect of acidification and climate change on element cycling and nutrient supply in forest soil. A reconstruction model of atmospheric deposition and nutrient uptake and cycling, MAKEDEP, was developed. An existing model of soil chemistry, SAFE, was analyzed and applied. SAFE+MAKEDEP were then applied in combination with the RAINS model to perform scenario analyses of soil acidification/recovery for six European forest sites. A decomposition model intended to run in conjunction with the SAFE model was developed. Key elements were N, Ca, K, Mg, S and Al. In the decomposition model, only carbon release was included to date.The results show, that understanding the history of soil geochemistry is important for modelling the system and for projecting the future impact of acidification on nutrient supply in forest soils. The applied reconstruction models of acid deposition (MAKEDEP, RAINS) seem to generate reasonable and consistent estimates of historic acid deposition, so that present day conditions can be simulated starting from pre-acidification conditions. From applications of the SAFE model to large-scale forest manipulation experiments, we conclude that the geochemical processes and the degree of detail in process descriptions included in SAFE are adequate to capture the most important aspects of soil solution dynamics of forest soils in northern and central Europe. Therefore, SAFE is appropriate for the simulation of acidification and recovery scenarios for these soils. The precision in model prediction on a more general scale is often limited by factors other than model formulation, such as consistency and representativity of input data. It is shown that the physical

  16. Iron cycling at corroding carbon steel surfaces.

    Science.gov (United States)

    Lee, Jason S; McBeth, Joyce M; Ray, Richard I; Little, Brenda J; Emerson, David

    2013-01-01

    Surfaces of carbon steel (CS) exposed to mixed cultures of iron-oxidizing bacteria (FeOB) and dissimilatory iron-reducing bacteria (FeRB) in seawater media under aerobic conditions were rougher than surfaces of CS exposed to pure cultures of either type of microorganism. The roughened surface, demonstrated by profilometry, is an indication of loss of metal from the surface. In the presence of CS, aerobically grown FeOB produced tight, twisted helical stalks encrusted with iron oxides. When CS was exposed anaerobically in the presence of FeRB, some surface oxides were removed. However, when the same FeOB and FeRB were grown together in an aerobic medium, FeOB stalks were less encrusted with iron oxides and appeared less tightly coiled. These observations suggest that iron oxides on the stalks were reduced and solubilized by the FeRB. Roughened surfaces of CS and denuded stalks were replicated with culture combinations of different species of FeOB and FeRB under three experimental conditions. Measurements of electrochemical polarization resistance established different rates of corrosion of CS in aerobic and anaerobic media, but could not differentiate rate differences between sterile controls and inoculated exposures for a given bulk concentration of dissolved oxygen. Similarly, total iron in the electrolyte could not be used to differentiate treatments. The experiments demonstrate the potential for iron cycling (oxidation and reduction) on corroding CS in aerobic seawater media.

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

    Science.gov (United States)

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

    2012-01-01

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

  18. Responses of aboveground and belowground forest carbon stocks to disturbances in boreal forests of Northeastern China

    Science.gov (United States)

    Huang, Chao; He, Hong S.; Hawbaker, Todd J.; Liang, Yu; Gong, Peng; Wu, Wuzhiwei; Zhu, Zhiliang

    2016-04-01

    Boreal forests represents about 1/3 of forest area and 1/3 of forest carbon on earth. Carbon dynamics of boreal forests are sensitive to climate change, natural (e.g., fire) and anthropogenic (e.g., harvest) disturbances. Field-based studies suggest that disturbances alter species composition, stand structure, and litter decomposition, and have significant effects on boreal forest carbon dynamics. Most of these studies, however, covered a relatively short period of time (e.g., few decades), which is limited in revealing such long-term effects of disturbances. Models are therefore developed as important tools in exploring the long-term (e.g., hundreds of years) effects of disturbances on forest carbon dynamics. In this study, we applied a framework of coupling forest ecosystem and landscape model to evaluating the effect of fire, harvest and their interactions on carbon stocks in a boreal forest landscape of Northeastern China. We compared the simulation results under fire, harvest and fire-harvest interaction scenarios with the simulated value of succession scenario at 26 landtypes over 150 years at a 10-year time step. Our results suggest that aboveground and belowground carbon are significantly reduced by fire and harvest over 150years. Fire reduced aboveground carbon by 2.3±0.6 ton/ha, harvest by 6.0±1.4 ton/ha, and fire and harvest interaction by 8.0±1.9 tons/ha. Fire reduced belowground carbon by 4.6±3.4 ton/ha, harvest by 5.0±3.5 ton/ha, and fire-harvest interaction by 5.7±3.7 tons/ha. The divergent response of carbon stocks among landtypes and between disturbance scenarios was due to the spatial interactions between fire, harvest, and species composition. Our results indicated that boreal forests carbon stocks prediction needs to consider the effects of fire and harvest for improving the estimation accuracy.

  19. Uncertainties in mapping forest carbon in urban ecosystems.

    Science.gov (United States)

    Chen, Gang; Ozelkan, Emre; Singh, Kunwar K; Zhou, Jun; Brown, Marilyn R; Meentemeyer, Ross K

    2017-02-01

    Spatially explicit urban forest carbon estimation provides a baseline map for understanding the variation in forest vertical structure, informing sustainable forest management and urban planning. While high-resolution remote sensing has proven promising for carbon mapping in highly fragmented urban landscapes, data cost and availability are the major obstacle prohibiting accurate, consistent, and repeated measurement of forest carbon pools in cities. This study aims to evaluate the uncertainties of forest carbon estimation in response to the combined impacts of remote sensing data resolution and neighborhood spatial patterns in Charlotte, North Carolina. The remote sensing data for carbon mapping were resampled to a range of resolutions, i.e., LiDAR point cloud density - 5.8, 4.6, 2.3, and 1.2 pt s/m(2), aerial optical NAIP (National Agricultural Imagery Program) imagery - 1, 5, 10, and 20 m. Urban spatial patterns were extracted to represent area, shape complexity, dispersion/interspersion, diversity, and connectivity of landscape patches across the residential neighborhoods with built-up densities from low, medium-low, medium-high, to high. Through statistical analyses, we found that changing remote sensing data resolution introduced noticeable uncertainties (variation) in forest carbon estimation at the neighborhood level. Higher uncertainties were caused by the change of LiDAR point density (causing 8.7-11.0% of variation) than changing NAIP image resolution (causing 6.2-8.6% of variation). For both LiDAR and NAIP, urban neighborhoods with a higher degree of anthropogenic disturbance unveiled a higher level of uncertainty in carbon mapping. However, LiDAR-based results were more likely to be affected by landscape patch connectivity, and the NAIP-based estimation was found to be significantly influenced by the complexity of patch shape.

  20. Nitrogen Deposition to and Cycling in a Deciduous Forest

    Directory of Open Access Journals (Sweden)

    Sara C. Pryor

    2001-01-01

    Full Text Available The project described here seeks to answer questions regarding the role increased nitrogen (N deposition is playing in enhanced carbon (C sequestration in temperate mid-latitude forests, using detailed measurements from an AmeriFlux tower in southern Indiana (Morgan-Monroe State Forest, or MMSF. The measurements indicate an average atmosphere-surface N flux of approximately 6 mg-N m-2 day-1 during the 2000 growing season, with approximately 40% coming from dry deposition of ammonia (NH3, nitric acid (HNO3, and particle-bound N. Wet deposition and throughfall measurements indicate significant canopy uptake of N (particularly NH4+ at the site, leading to a net canopy exchange (NCE of –6 kg-N ha-1 for the growing season. These data are used in combination with data on the aboveground C:N ratio, litterfall flux, and soil net N mineralization rates to indicate the level of potential perturbation of C sequestration at this site.

  1. Estimation of Direct Carbon Emissions from Chinese Forest Fires

    Institute of Scientific and Technical Information of China (English)

    TIANXiaorui; GAOChengde; SHULifu; WANGMingyu; YANGXiaohui

    2004-01-01

    Many studies indicated that the products of biosphere burning have short and long-term effects on the atmosphere. Vegetation burning can produce some gases which have significant influence on environment, including some greenhouse gases as CO2 and CH4, etc. Smoke aerosols produced from burning also influence global climate and atmospheric chemistry. The paper calculates the consumed biomass due to forest fires according to the statistics of forest fires from 1991 to 2000 and research results of biomass of Chinese forests. During the study period, forest fires burned average 5Tg-7Tg biomass each year and directly emitted 20.24 Tg-28.56 Tg carbon. In 1991-2000, average emission of carbon dioxide and CH4 account for 2.7%-3.9% and 3.3%-4.7% of the total emission of China (calculating with the data of 2000), respectively.

  2. Modeling carbon cycle dynamics and response to drought in semi-arid ecosystems

    Science.gov (United States)

    Hilton, T. W.; Fox, A. M.; Krofcheck, D. J.; Litvak, M. E.

    2012-12-01

    The southwestern United States is presently experiencing a multi-year drought. Though the carbon uptake per unit area of the semi-arid biomes in this region is smaller than that of more temperate biomes, these biomes cover roughly 40 percent of the world's land surface, and thus make a significant contribution to the global terrestrial biological carbon cycle. Here we test the ability of two land surface model structures to diagnose the carbon cycle dynamics of semi-arid landscapes during the ongoing extreme drought. We use the New Mexico Elevation Gradient (NMEG) as a testbed for these modeling experiments. The NMEG comprises eight eddy covariance towers observing ecosystems ranging from desert grassland ( 1600 m elevation) to alpine mixed coniferous forest ( 3000 m elevation). During the drought the ecosystems observed by these towers saw their annual net carbon uptake decline between 33 and 100 percent (50 to 150 gC m^{-2} year^{-1}), with two of the eight sites becoming net sources of carbon to the atmosphere and one transitioning from a net carbon sink to carbon-neutral. We parametrize a simple light-use efficiency (LUE)-based model (Vegetation Photosynthesis and Respiration Model, VPRM) and a complex model which simulates many land surface processes (Community Land Model, CLM). We explore the capacity of both models to diagnose the terrestrial carbon cycle in semi-arid biomes where water availability is highly episodic.

  3. [Forest carbon storage and fuel carbon emission in Tanjiang River basin].

    Science.gov (United States)

    Chen, Zhiliang; Xia, Nianhe; Wu, Zhifeng; Cheng, Jiong; Liu, Ping

    2006-10-01

    The investigation on the forest carbon storage and fuel carbon emission in Tanjiang River basin showed that since 1990, the forests in Tanjiang River basin acted as a carbon sink, and this action was increased with time and with economic development. The net carbon uptake by the forests was 1.0579 x 10 (7) t in 1990 and 1.28061 x 10 (7) t in 2002, with an annual increment of 1.856 x 10(5) t, while the fuel carbon emission was 9. 508 x 10(5) t in 1990 and 1.8562 x 10(6) t in 2002, with an annual increment of 7.0 x 10(4) t. In 2003, the fuel carbon emission was up to 2.1968 x 10(6) t, 3.406 x 105 t more than that in 2002. In 2002, the energy consumption per 10(4) yuan GDP in Tanjiang River basin was 2.21 t standard coal, higher than the average consumption (1.81 t standard coal) in the Pearl River delta. If the fuel consumption decreased to the average level, the carbon emission in Tanjiang River basin would be reduced by 3.360 x 10(5) t, which was higher than the annual increment of forest net carbon uptake in the basin. From the viewpoint of net carbon uptake and emission in a basin, more attention should be paid to the relations between forest carbon sink and human activities.

  4. Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

    Energy Technology Data Exchange (ETDEWEB)

    Cusack, D.; Silver, W.L.; Torn, M.S.; McDowell, W.H.

    2011-04-15

    Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and upper elevation tropical rain forests in Puerto Rico to explore the responses of above- and belowground C pools to N addition. As expected, tree stem growth and litterfall productivity did not respond to N fertilization in either of these Nrich forests, indicating a lack of N limitation to net primary productivity (NPP). In contrast, soil C concentrations increased significantly with N fertilization in both forests, leading to larger C stocks in fertilized plots. However, different soil C pools responded to N fertilization differently. Labile (low density) soil C fractions and live fine roots declined with fertilization, while mineral-associated soil C increased in both forests. Decreased soil CO2 fluxes in fertilized plots were correlated with smaller labile soil C pools in the lower elevation forest (R2 = 0.65, p\\0.05), and with lower live fine root biomass in the upper elevation forest (R2 = 0.90, p\\0.05). Our results indicate that soil C storage is sensitive to N deposition in tropical forests, even where plant productivity is not N-limited. The mineral-associated soil C pool has the potential to respond relatively quickly to N additions, and can drive increases in bulk soil C stocks in tropical forests.

  5. Lakes and reservoirs as regulators of carbon cycling and climate

    NARCIS (Netherlands)

    Tranvik, L.J.; Downing, J.A.; Cotner, J.B.; Loiselle, S.A.; Striegl, R.G.; Ballatore, T.J.; Dillon, P.; Knoll, L.B.; Kutser, T.; Larsen, S.; Laurion, I.; Leech, D.M.; McAllister, S.L.; McKnight, D.M.; Melack, J.; Overholt, E.; Porter, J.A.; Prairie, Y.T.; Renwick, W.H.; Roland, F.; Sherman, B.S.; Schindler, D.W.; Sobek, S.; Tremblay, A.; Vanni, M.J.; Verschoor, A.M.; von Wachenfeldt, E.; Weyhenmeyer, G.

    2009-01-01

    We explore the role of lakes in carbon cycling and global climate, examine the mechanisms influencing carbon pools and transformations in lakes, and discuss how the metabolism of carbon in the inland waters is likely to change in response to climate. Furthermore, we project changes as global climate

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

    Science.gov (United States)

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

    2016-01-01

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

  7. Cross-continental comparison of the functional composition and carbon allocation of two altitudinal forest transects in Ecuador and Rwanda.

    Science.gov (United States)

    Bauters, Marijn; Bruneel, Stijn; Demol, Miro; Taveirne, Cys; Van Der Heyden, Dries; Boeckx, Pascal; Kearsley, Elizabeth; Cizungu, Landry; Verbeeck, Hans

    2016-04-01

    Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Africa, focussing on shifts in carbon allocation, forest structure and functional composition. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed adaption mechanisms are.

  8. Energy dissipation in intercalated carbon nanotube forests with metal layers

    Science.gov (United States)

    Boddu, Veera M.; Brenner, Matthew W.

    2016-02-01

    Vertically aligned carbon nanotube (CNT) forests were synthesized to study their quasi-static mechanical properties in a layered configuration with metallization. The top and bottom surfaces of CNT forests were metalized with Ag, Fe, and In using paste, sputtering, and thermal evaporation, respectively. Stacks of one, two, and three layers of these forests were assembled and compressed to measure their mechanical properties. The samples were strain limited to 0.7, and the results indicate that energy dissipation is approximately linear with respect to the number of layers and relatively independent of metal type. The energy per unit volume was approximately the same for all samples. Successive stacking of CNT forests reduces local buckling events, which is enhanced with a thick Ag deposition on the CNT forest surface. Young's modulus was also observed to increase as the number of layers was increased. These results are useful in the design of composite materials for high energy absorption and high stiffness applications.

  9. Impact response by a foamlike forest of coiled carbon nanotubes

    Science.gov (United States)

    Daraio, Chiara; Nesterenko, Vitali F.; Jin, Sungho; Wang, Wei; Rao, Apparao M.

    2006-09-01

    We studied the dynamic response of a foamlike forest of coiled carbon nanotubes under high strain rate deformation using a simple drop-ball test. The method is based on measuring the dynamic force between the ball and the foam on the substrate during the stages of penetration and restitution. The analysis of the forest's morphology after impact has shown no trace of plastic deformation and a full recovery of the foamlike layer of coiled carbon nanotubes under various impact velocities. The contact force exhibits a strongly nonlinear dependence on displacement and appears fundamentally different from the response of a forest of straight carbon nanotubes, and from the Hertzian type of plane-sphere interaction. "Brittle" fracture of the foamlike layer is observed after repeated high velocity impacts. Such layers of coiled nanotubes may be used as a strongly nonlinear spring in discrete systems for monitoring their dynamic behavior and as a nanostructure for localized microimpact protection.

  10. Vegetation carbon sequestration in Chinese forests from 2010 to 2050.

    Science.gov (United States)

    He, Nianpeng; Wen, Ding; Zhu, Jianxing; Tang, Xuli; Xu, Li; Zhang, Li; Hu, Huifeng; Huang, Mei; Yu, Guirui

    2016-08-26

    Forests store a large part of the terrestrial vegetation carbon (C) and have high C sequestration potential. Here, we developed a new forest C sequestration (FCS) model based on the secondary succession theory, to estimate vegetation C sequestration capacity in China's forest vegetation. The model used the field measurement data of 3161 forest plots and three future climate scenarios. The results showed that logistic equations provided a good fit for vegetation biomass with forest age in natural and planted forests. The FCS model has been verified with forest biomass data, and model uncertainty is discussed. The increment of vegetation C storage in China's forest vegetation from 2010 to 2050 was estimated as 13.92 Pg C, while the average vegetation C sequestration rate was 0.34 Pg C yr(-1) with a 95% confidence interval of 0.28-0.42 Pg C yr(-1) , which differed significantly between forest types. The largest contributor to the increment was deciduous broadleaf forest (37.8%), while the smallest was deciduous needleleaf forest (2.7%). The vegetation C sequestration rate might reach its maximum around 2020, although vegetation C storage increases continually. It is estimated that vegetation C sequestration might offset 6-8% of China's future emissions. Furthermore, there was a significant negative relationship between vegetation C sequestration rate and C emission rate in different provinces of China, suggesting that developed provinces might need to compensate for undeveloped provinces through C trade. Our findings will provide valuable guidelines to policymakers for designing afforestation strategies and forest C trade in China.

  11. Fluxes of CO2, CH4, CO, BVOCs, NOx, and O3 in an Old Growth Amazonian Forest: Ecosystem Processes, Carbon Cycle, Atmospheric Chemistry, and Feedbacks on Climate

    Energy Technology Data Exchange (ETDEWEB)

    Wofsy, Steven C. [Harvard Univ., Cambridge, MA (United States)

    2016-12-20

    part of the cycling processes occurring in the top layers. Methane fluxes showed no statistical difference between 2015 wet and dry seasons, and the forest at this site appear to be a methane sink throughout the year. The vertical profiles suggest that if a methane source exists in this forest, it might be in the canopy. Next steps include modeling and analysis using the Master Chemical Mechanism (Jenkin et al., 1997; Saunders et al., 2003 (A/B); http://mcm.leeds.ac.uk/MCM/) and the Ecosystem Demography-2 (ED-2) model. A final manuscript with the results from this work is in preparation and expected to be submitted for publication within the next several months. Publications to date are listed below.

  12. Markedly divergent estimates of Amazon forest carbon density from ground plots and satellites

    Science.gov (United States)

    Mitchard, Edward T A; Feldpausch, Ted R; Brienen, Roel J W; Lopez-Gonzalez, Gabriela; Monteagudo, Abel; Baker, Timothy R; Lewis, Simon L; Lloyd, Jon; Quesada, Carlos A; Gloor, Manuel; ter Steege, Hans; Meir, Patrick; Alvarez, Esteban; Araujo-Murakami, Alejandro; Aragão, Luiz E O C; Arroyo, Luzmila; Aymard, Gerardo; Banki, Olaf; Bonal, Damien; Brown, Sandra; Brown, Foster I; Cerón, Carlos E; Chama Moscoso, Victor; Chave, Jerome; Comiskey, James A; Cornejo, Fernando; Corrales Medina, Massiel; Da Costa, Lola; Costa, Flavia R C; Di Fiore, Anthony; Domingues, Tomas F; Erwin, Terry L; Frederickson, Todd; Higuchi, Niro; Honorio Coronado, Euridice N; Killeen, Tim J; Laurance, William F; Levis, Carolina; Magnusson, William E; Marimon, Beatriz S; Marimon Junior, Ben Hur; Mendoza Polo, Irina; Mishra, Piyush; Nascimento, Marcelo T; Neill, David; Núñez Vargas, Mario P; Palacios, Walter A; Parada, Alexander; Pardo Molina, Guido; Peña-Claros, Marielos; Pitman, Nigel; Peres, Carlos A; Poorter, Lourens; Prieto, Adriana; Ramirez-Angulo, Hirma; Restrepo Correa, Zorayda; Roopsind, Anand; Roucoux, Katherine H; Rudas, Agustin; Salomão, Rafael P; Schietti, Juliana; Silveira, Marcos; de Souza, Priscila F; Steininger, Marc K; Stropp, Juliana; Terborgh, John; Thomas, Raquel; Toledo, Marisol; Torres-Lezama, Armando; van Andel, Tinde R; van der Heijden, Geertje M F; Vieira, Ima C G; Vieira, Simone; Vilanova-Torre, Emilio; Vos, Vincent A; Wang, Ophelia; Zartman, Charles E; Malhi, Yadvinder; Phillips, Oliver L

    2014-01-01

    Aim The accurate mapping of forest carbon stocks is essential for understanding the global carbon cycle, for assessing emissions from deforestation, and for rational land-use planning. Remote sensing (RS) is currently the key tool for this purpose, but RS does not estimate vegetation biomass directly, and thus may miss significant spatial variations in forest structure. We test the stated accuracy of pantropical carbon maps using a large independent field dataset. Location Tropical forests of the Amazon basin. The permanent archive of the field plot data can be accessed at: http://dx.doi.org/10.5521/FORESTPLOTS.NET/2014_1 Methods Two recent pantropical RS maps of vegetation carbon are compared to a unique ground-plot dataset, involving tree measurements in 413 large inventory plots located in nine countries. The RS maps were compared directly to field plots, and kriging of the field data was used to allow area-based comparisons. Results The two RS carbon maps fail to capture the main gradient in Amazon forest carbon detected using 413 ground plots, from the densely wooded tall forests of the north-east, to the light-wooded, shorter forests of the south-west. The differences between plots and RS maps far exceed the uncertainties given in these studies, with whole regions over- or under-estimated by > 25%, whereas regional uncertainties for the maps were reported to be < 5%. Main conclusions Pantropical biomass maps are widely used by governments and by projects aiming to reduce deforestation using carbon offsets, but may have significant regional biases. Carbon-mapping techniques must be revised to account for the known ecological variation in tree wood density and allometry to create maps suitable for carbon accounting. The use of single relationships between tree canopy height and above-ground biomass inevitably yields large, spatially correlated errors. This presents a significant challenge to both the forest conservation and remote sensing communities

  13. Forest carbon budgets in Southeast Asia following harvesting and land cover change

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Terrestrial ecosystems play an important role in the global carbon (C)cycle. Tropical forests in Southeast Asia are constantly changing as a result of harvesting and conversion to other land cover. As a result of these changes, research on C budgets of forest ecosystems has intensified in the region over thelast few years. This paper reviews and synthesizes the available information. Natural forests in SE Asia typically contain a high C density (up to 500 Mg/ha). Logging activities are responsible for at least 50% decline in forest C density.Complete deforestation (conversion from forest to grassland or annual crops) results in C density of less than 40 Mg/ha. Conversion to tree plantations and other woody perennial crops also reduces C density to less than 50% of the originalC forest stocks. While much information has been generated recently, there are still large gaps of information on C budgets of tropical forests and its conversion to other land uses in SE Asia. There is therefore a need to intensify research in this area.

  14. Quantifying above- and belowground biomass carbon loss with forest conversion in tropical lowlands of Sumatra (Indonesia).

    Science.gov (United States)

    Kotowska, Martyna M; Leuschner, Christoph; Triadiati, Triadiati; Meriem, Selis; Hertel, Dietrich

    2015-10-01

    Natural forests in South-East Asia have been extensively converted into other land-use systems in the past decades and still show high deforestation rates. Historically, lowland forests have been converted into rubber forests, but more recently, the dominant conversion is into oil palm plantations. While it is expected that the large-scale conversion has strong effects on the carbon cycle, detailed studies quantifying carbon pools and total net primary production (NPPtotal ) in above- and belowground tree biomass in land-use systems replacing rainforest (incl. oil palm plantations) are rare so far. We measured above- and belowground carbon pools in tree biomass together with NPPtotal in natural old-growth forests, 'jungle rubber' agroforests under natural tree cover, and rubber and oil palm monocultures in Sumatra. In total, 32 stands (eight plot replicates per land-use system) were studied in two different regions. Total tree biomass in the natural forest (mean: 384 Mg ha(-1) ) was more than two times higher than in jungle rubber stands (147 Mg ha(-1) ) and >four times higher than in monoculture rubber and oil palm plantations (78 and 50 Mg ha(-1) ). NPPtotal was higher in the natural forest (24 Mg ha(-1)  yr(-1) ) than in the rubber systems (20 and 15 Mg ha(-1)  yr(-1) ), but was highest in the oil palm system (33 Mg ha(-1)  yr(-1) ) due to very high fruit production (15-20 Mg ha(-1)  yr(-1) ). NPPtotal was dominated in all systems by aboveground production, but belowground productivity was significantly higher in the natural forest and jungle rubber than in plantations. We conclude that conversion of natural lowland forest into different agricultural systems leads to a strong reduction not only in the biomass carbon pool (up to 166 Mg C ha(-1) ) but also in carbon sequestration as carbon residence time (i.e. biomass-C:NPP-C) was 3-10 times higher in the natural forest than in rubber and oil palm plantations. © 2015 John Wiley & Sons Ltd.

  15. A large and persistent carbon sink in the world's forests

    Science.gov (United States)

    Pan, Y.; Birdsey, R.A.; Fang, J.; Houghton, R.; Kauppi, P.E.; Kurz, W.A.; Phillips, O.L.; Shvidenko, A.; Lewis, S.L.; Canadell, J.G.; Ciais, P.; Jackson, R.B.; Pacala, S.W.; McGuire, A.D.; Piao, S.; Rautiainen, A.; Sitch, S.; Hayes, D.

    2011-01-01

    The terrestrial carbon sink has been large in recent decades, but its size and location remain uncertain. Using forest inventory data and long-term ecosystem carbon studies, we estimate a total forest sink of 2.4 ?? 0.4 petagrams of carbon per year (Pg C year-1) globally for 1990 to 2007. We also estimate a source of 1.3 ?? 0.7 Pg C year-1 from tropical land-use change, consisting of a gross tropical deforestation emission of 2.9 ?? 0.5 Pg C year-1 partially compensated by a carbon sink in tropical forest regrowth of 1.6 ?? 0.5 Pg C year-1. Together, the fluxes comprise a net global forest sink of 1.1 ?? 0.8 Pg C year-1, with tropical estimates having the largest uncertainties. Our total forest sink estimate is equivalent in magnitude to the terrestrial sink deduced from fossil fuel emissions and land-use change sources minus ocean and atmospheric sinks.

  16. An Assessment of Carbon Storage in China’s Arboreal Forests

    Directory of Open Access Journals (Sweden)

    Weiwei Shao

    2017-04-01

    Full Text Available In the years 2009–2013, China carried out its eighth national survey of forest resources. Based on the survey data, this paper used a biomass conversion function method to evaluate the carbon stores and carbon density of China’s arboreal forests. The results showed that: (1 By age group, the largest portion of carbon stores in China’s arboreal forests are in middle-aged forests. Over-mature forests have the least carbon storage; (2 By origin, natural forests of all age groups have higher carbon storage and carbon density than man-made forest plantations. The carbon density of natural forests and forest plantations increases gradually with the age of the trees; (3 By type (dominant tree species, the 18 most abundant types of arboreal forest in China account for approximately 94% of the nation’s total arboreal forest biomass and carbon storage. Among these, broadleaf mixed and Quercus spp. form the two largest portions. Taxus spp. forests, while comprising a very small portion of China’s forested area, have very high carbon density; (4 By region, the overall arboreal forest carbon storage is highest in the southwest part of China, and lowest in the northwest. However, because of differences in land use and forest coverage ratios, regions with arboreal forests of high carbon density are not necessarily the same regions that have high overall carbon storage; (5 By province, Heilongjiang, Yunnan, Tibet, Sichuan, Inner Mongolia, and Jilin have rather high carbon storage. The arboreal forests in Tibet, Jilin, Xinjiang, Sichuan, Yunnan, and Hainan have a rather high carbon density. This paper’s evaluation of carbon storage in China’s arboreal forests is a valuable reference for interpreting the role and function of Chinese ecosystems in coping with global climate change.

  17. Carbon stock and carbon turnover in boreal and temperate forests - Integration of remote sensing data and global vegetation models

    Science.gov (United States)

    Thurner, Martin; Beer, Christian; Carvalhais, Nuno; Forkel, Matthias; Tito Rademacher, Tim; Santoro, Maurizio; Tum, Markus; Schmullius, Christiane

    2016-04-01

    Long-term vegetation dynamics are one of the key uncertainties of the carbon cycle. There are large differences in simulated vegetation carbon stocks and fluxes including productivity, respiration and carbon turnover between global vegetation models. Especially the implementation of climate-related mortality processes, for instance drought, fire, frost or insect effects, is often lacking or insufficient in current models and their importance at global scale is highly uncertain. These shortcomings have been due to the lack of spatially extensive information on vegetation carbon stocks, which cannot be provided by inventory data alone. Instead, we recently have been able to estimate northern boreal and temperate forest carbon stocks based on radar remote sensing data. Our spatially explicit product (0.01° resolution) shows strong agreement to inventory-based estimates at a regional scale and allows for a spatial evaluation of carbon stocks and dynamics simulated by global vegetation models. By combining this state-of-the-art biomass product and NPP datasets originating from remote sensing, we are able to study the relation between carbon turnover rate and a set of climate indices in northern boreal and temperate forests along spatial gradients. We observe an increasing turnover rate with colder winter temperatures and longer winters in boreal forests, suggesting frost damage and the trade-off between frost adaptation and growth being important mortality processes in this ecosystem. In contrast, turnover rate increases with climatic conditions favouring drought and insect outbreaks in temperate forests. Investigated global vegetation models from the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), including HYBRID4, JeDi, JULES, LPJml, ORCHIDEE, SDGVM, and VISIT, are able to reproduce observation-based spatial climate - turnover rate relationships only to a limited extent. While most of the models compare relatively well in terms of NPP, simulated

  18. Current systematic carbon cycle observations and needs for implementing a policy-relevant carbon observing system

    Directory of Open Access Journals (Sweden)

    P. Ciais

    2013-07-01

    Full Text Available A globally integrated carbon observation and analysis system is needed to improve the fundamental understanding of the global carbon cycle, to improve our ability to project future changes, and to verify the effectiveness of policies aiming to reduce greenhouse gas emissions and increase carbon sequestration. Building an integrated carbon observation system requires transformational advances from the existing sparse, exploratory framework towards a dense, robust, and sustained system in all components: anthropogenic emissions, the atmosphere, the ocean, and the terrestrial biosphere. The goal of this study is to identify the current state of carbon observations and needs for a global integrated carbon observation system that can be built in the next decade. A key conclusion is the substantial expansion (by several orders of magnitude of the ground-based observation networks required to reach the high spatial resolution for CO2 and CH4 fluxes, and for carbon stocks for addressing policy relevant objectives, and attributing flux changes to underlying processes in each region. In order to establish flux and stock diagnostics over remote areas such as the southern oceans, tropical forests and the Arctic, in situ observations will have to be complemented with remote-sensing measurements. Remote sensing offers the advantage of dense spatial coverage and frequent revisit. A key challenge is to bring remote sensing measurements to a level of long-term consistency and accuracy so that they can be efficiently combined in models to reduce uncertainties, in synergy with ground-based data. Bringing tight observational constraints on fossil fuel and land use change emissions will be the biggest challenge for deployment of a policy-relevant integrated carbon observation system. This will require in-situ and remotely sensed data at much higher resolution and density than currently achieved for natural fluxes, although over a small land area (cities, industrial

  19. Long-term soil warming and Carbon Cycle Feedbacks to the Climate System

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry M.

    2014-04-30

    The primary objective of the proposed research was to quantify and explain the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem. The research was done at an established soil warming experiment at the Harvard Forest in central Massachusetts – Barre Woods site established in 2001. In the field, a series of plant and soil measurements were made to quantify changes in C storage in the ecosystem and to provide insights into the possible relationships between C-storage changes and nitrogen (N) cycling changes in the warmed plots. Field measurements included: 1) annual woody increment; 2) litterfall; 3) carbon dioxide (CO2) efflux from the soil surface; 4) root biomass and respiration; 5) microbial biomass; and 6) net N mineralization and net nitrification rates. This research was designed to increase our understanding of how global warming will affect the capacity of temperate forest ecosystems to store C. The work explored how soil warming changes the interactions between the C and N cycles, and how these changes affect land-atmosphere feedbacks. This core research question framed the project – What are the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem? A second critical question was addressed in this research – What are the effects of a sustained in situ 5{degrees}C soil temperature increase on nitrogen (N) cycling in a northeastern deciduous forest ecosystem?

  20. Long-term soil warming and Carbon Cycle Feedbacks to the Climate System

    Energy Technology Data Exchange (ETDEWEB)

    Melillo, Jerry M.

    2014-04-30

    The primary objective of the proposed research was to quantify and explain the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem. The research was done at an established soil warming experiment at the Harvard Forest in central Massachusetts – Barre Woods site established in 2001. In the field, a series of plant and soil measurements were made to quantify changes in C storage in the ecosystem and to provide insights into the possible relationships between C-storage changes and nitrogen (N) cycling changes in the warmed plots. Field measurements included: 1) annual woody increment; 2) litterfall; 3) carbon dioxide (CO2) efflux from the soil surface; 4) root biomass and respiration; 5) microbial biomass; and 6) net N mineralization and net nitrification rates. This research was designed to increase our understanding of how global warming will affect the capacity of temperate forest ecosystems to store C. The work explored how soil warming changes the interactions between the C and N cycles, and how these changes affect land-atmosphere feedbacks. This core research question framed the project – What are the effects of a sustained in situ 5oC soil temperature increase on net carbon (C) storage in a northeastern deciduous forest ecosystem? A second critical question was addressed in this research – What are the effects of a sustained in situ 5{degrees}C soil temperature increase on nitrogen (N) cycling in a northeastern deciduous forest ecosystem?

  1. Monitoring coniferous forest biomass change using a Landsat trajectory-based approach

    Science.gov (United States)

    Magdalena Main-Knorn; Warren B. Cohen; Robert E. Kennedy; Wojciech Grodzki; Dirk Pflugmacher; Patrick Griffiths; Patrick Hostert

    2013-01-01

    Forest biomass is a major store of carbon and thus plays an important role in the regional and global carbon cycle. Accurate forest carbon sequestration assessment requires estimation of both forest biomass and forest biomass dynamics over time. Forest dynamics are characterized by disturbances and recovery, key processes affecting site productivity and the forest...

  2. Effect of disturbance on biomass, production and carbon dynamics in moist tropical forest of eastern Nepal

    Directory of Open Access Journals (Sweden)

    Tilak Prasad Gautam

    2016-04-01

    Full Text Available Background: Forest biomass is helpful to assess its productivity and carbon (C sequestration capacity. Several disturbance activities in tropical forests have reduced the biomass and net primary production (NPP leading to climate change. Therefore, an accurate estimation of forest biomass and C cycling in context of disturbances is required for implementing REDD (Reducing Emissions from Deforestation and Forest Degradation policy. Methods: Biomass and NPP of trees and shrubs were estimated by using allometric equations while herbaceous biomass was estimated by harvest method. Fine root biomass was determined from soil monolith. The C stock in vegetation was calculated by multiplying C concentration to dry weight. Results: Total stand biomass (Mg∙ha–1 in undisturbed forest stand (US was 960.4 while in disturbed forest stand (DS it was 449.1. The biomass (Mg∙ha–1 of trees, shrubs and herbs in US was 948.0, 4.4 and 1.4, respectively, while in DS they were 438.4, 6.1 and 1.2, respectively. Total NPP (Mg∙ha–1∙yr–1 was 26.58 (equivalent to 12.26 Mg C∙ha–1∙yr–1 in US and 14.91 (6.88 Mg C∙ha–1∙yr–1 in DS. Total C input into soil through litter plus root turnover was 6.78 and 3.35 Mg∙ha–1∙yr–1 in US and DS, respectively. Conclusions: Several disturbance activities resulted in the significant loss in stand biomass (53 %, NPP (44 %, and C sequestration capacity of tropical forest in eastern Nepal. The net uptake of carbon by the vegetation is far greater than that returned to the soil by the turnover of fine root and litter. Therefore, both stands of present forest act as carbon accumulating systems. Moreover, disturbance reflects higher C emissions which can be reduced by better management. Keywords: Tropical forest, Disturbance, Biomass, Production, Carbon cycling, Nepal

  3. Total carbon accumulation in a tropical forest landscape.

    Science.gov (United States)

    Sierra, Carlos A; Del Valle, Jorge I; Restrepo, Hector I

    2012-12-19

    Regrowing tropical forests worldwide sequester important amounts of carbon and restore part of the C emissions emitted by deforestation. However, there are large uncertainties concerning the rates of carbon accumulation after the abandonment of agricultural and pasture land. We report here accumulation of total carbon stocks (TCS) in a chronosequence of secondary forests at a mid-elevation landscape (900-1200 m asl) in the Andean mountains of Colombia. We found positive accumulation rates for all ecosystem pools except soil carbon, which showed no significant trend of recovery after 36 years of secondary succession. We used these data to develop a simple model to predict accumulation of TCS over time. This model performed remarkably well predicting TCS at other chronosequences in the Americas (Root Mean Square Error < 40 Mg C ha-1), which provided an opportunity to explore different assumptions in the calculation of large-scale carbon budgets. Simulations of TCS with our empirical model were used to test three assumptions often made in carbon budgets: 1) the use of carbon accumulation in tree aboveground biomass as a surrogate for accumulation of TCS, 2) the implicit consideration of carbon legacies from previous land-use, and 3) the omission of landscape age in calculating accumulation rates of TCS. Our simulations showed that in many situations carbon can be released from regrowing secondary forests depending on the amount of carbon legacies and the average age of the landscape. In most cases, the rates used to predict carbon accumulation in the Americas were above the rates predicted in our simulations. These biome level rates seemed to be realistic only in landscapes not affected by carbon legacies from previous land-use and mean ages of around 10 years.

  4. Forest Carbon-Storage as a Peacebuilding Strategy

    DEFF Research Database (Denmark)

    Nunez, Augusto Carlos Castro

    carbon biomass and armed conflicts. With this in mind, the present dissertation utilizes household-level surveys and data at the municipal-scale to assess potential for the integration of forest-carbon storage and peacebuilding efforts. Specifically, household surveys were used to identify factors....... Results suggest high potential for adoption of REDD+ among conflict affected farmers and that peacebuilding efforts, such as land tenure programs, predispose farmers toward forest conservation. Nonetheless, deforestation is still present in the study area. Similarly, our results show potential national...

  5. Carbon cycle: Ocean dissolved organics matter

    Science.gov (United States)

    Amon, Rainer M. W.

    2016-12-01

    Large quantities of organic carbon are stored in the ocean, but its biogeochemical behaviour is elusive. Size-age-composition relations now quantify the production of tiny organic molecules as a major pathway for carbon sequestration.

  6. Carbon cycle: New pathways in the sand

    Science.gov (United States)

    Rao, Alexandra

    2017-01-01

    Organic carbon decomposition in anoxic marine sediments was thought to be dominated by bacteria, but experimental data and microbial culture studies now show that microalgae buried in coastal sands may also play an important role in carbon turnover.

  7. The production of phytolith-occluded carbon in China's forests: implications to biogeochemical carbon sequestration.

    Science.gov (United States)

    Song, Zhaoliang; Liu, Hongyan; Li, Beilei; Yang, Xiaomin

    2013-09-01

    The persistent terrestrial carbon sink regulates long-term climate change, but its size, location, and mechanisms remain uncertain. One of the most promising terrestrial biogeochemical carbon sequestration mechanisms is the occlusion of carbon within phytoliths, the silicified features that deposit within plant tissues. Using phytolith content-biogenic silica content transfer function obtained from our investigation, in combination with published silica content and aboveground net primary productivity (ANPP) data of leaf litter and herb layer in China's forests, we estimated the production of phytolith-occluded carbon (PhytOC) in China's forests. The present annual phytolith carbon sink in China's forests is 1.7 ± 0.4 Tg CO2  yr(-1) , 30% of which is contributed by bamboo because the production flux of PhytOC through tree leaf litter for bamboo is 3-80 times higher than that of other forest types. As a result of national and international bamboo afforestation and reforestation, the potential of phytolith carbon sink for China's forests and world's bamboo can reach 6.8 ± 1.5 and 27.0 ± 6.1 Tg CO2  yr(-1) , respectively. Forest management practices such as bamboo afforestation and reforestation may significantly enhance the long-term terrestrial carbon sink and contribute to mitigation of global climate warming. © 2013 John Wiley & Sons Ltd.

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

    Directory of Open Access Journals (Sweden)

    Gaoyang Cui

    Full Text Available 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.

  9. Remote sensing assessment of carbon storage by urban forest

    Science.gov (United States)

    Kanniah, K. D.; Muhamad, N.; Kang, C. S.

    2014-02-01

    Urban forests play a crucial role in mitigating global warming by absorbing excessive CO2 emissions due to transportation, industry and house hold activities in the urban environment. In this study we have assessed the role of trees in an urban forest, (Mutiara Rini) located within the Iskandar Development region in south Johor, Malaysia. We first estimated the above ground biomass/carbon stock of the trees using allometric equations and biometric data (diameter at breast height of trees) collected in the field. We used remotely sensed vegetation indices (VI) to develop an empirical relationship between VI and carbon stock. We used five different VIs derived from a very high resolution World View-2 satellite data. Results show that model by [1] and Normalized Difference Vegetation Index are correlated well (R2 = 0.72) via a power model. We applied the model to the entire study area to obtain carbon stock of urban forest. The average carbon stock in the urban forest (mostly consisting of Dipterocarp species) is ~70 t C ha-1. Results of this study can be used by the Iskandar Regional Development Authority to better manage vegetation in the urban environment to establish a low carbon city in this region.

  10. Disturbance and the carbon balance of US forests: A quantitative review of impacts from harvests, fires, insects, and droughts

    Science.gov (United States)

    Williams, Christopher A.; Gu, Huan; MacLean, Richard; Masek, Jeffrey G.; Collatz, G. James

    2016-08-01

    Disturbances are a major determinant of forest carbon stocks and uptake. They generally reduce land carbon stocks but also initiate a regrowth legacy that contributes substantially to the contemporary rate of carbon stock increase in US forestlands. As managers and policy makers increasingly look to forests for climate protection and mitigation, and because of increasing concern about changes in disturbance intensity and frequency, there is a need for synthesis and integration of current understanding about the role of disturbances and other processes in governing forest carbon cycle dynamics, and the likely future of this and other sinks for atmospheric carbon. This paper aims to address that need by providing a quantitative review of the distribution, extent and carbon impacts of the major disturbances active in the US. We also review recent trends in disturbances, climate, and other global environmental changes and consider their individual and collective contributions to the US carbon budget now and in the likely future. Lastly, we identify some key challenges and opportunities for future research needed to improve current understanding, advance predictive capabilities, and inform forest management in the face of these pressures. Harvest is found to be the most extensive disturbance both in terms of area and carbon impacts, followed by fire, windthrow and bark beetles, and lastly droughts. Collectively these lead to the gross loss of about 200 Tg C y- 1 in live biomass annually across the conterminous US. At the same time, the net change in forest carbon stocks is positive (190 Tg C y- 1), indicating not only forest resilience but also an apparently large response to growth enhancements such as fertilization by CO2 and nitrogen. Uncertainty about disturbance legacies, disturbance interactions, likely trends, and global change factors make the future of the US forest carbon sink unclear. While there is scope for management to enhance carbon sinks in US forests

  11. Economics of forest and forest carbon projects. Translating lessons learned into national REDD+ implementation

    DEFF Research Database (Denmark)

    Zaballa Romero, Mauricio Ernesto; Trærup, Sara Lærke Meltofte; Wieben, Emilie

    The financial implications of implementing a new forest management paradigm have not been well understood and have often been underestimated. Resource needs for e.g., stakeholder consultation, capacity building and addressing the political economy are seldom fully accounted for in the resource...... and lessons learned with policymakers, project developers and stakeholders, with the objective to inform forest project and strategy development. It presents experiences and advice on the risks, costs and revenues of forest projects, thereby informing not only the development of future REDD+ initiatives......, it appears that REDD+ payments alone, especially at current prices, will not deliver the revenues that cover all expenses of transparent and long-term mitigation of forest carbon emissions. Instead the findings underline the importance of building up forest operations which effectively manages risk...

  12. The role of urbanization in the global carbon cycle

    Directory of Open Access Journals (Sweden)

    Galina eChurkina

    2016-01-01

    Full Text Available Urban areas account for more than 70% of CO2 emissions from burning fossil fuels. Urban expansion in tropics is responsible for 5% of the annual emissions from land use change. Here I show that the effect of urbanization on the global carbon cycle extends beyond these emissions. I quantify the contribution of urbanization to the major carbon fluxes and pools globally and identify gaps crucial for predicting the evolution of the carbon cycle in the future. Urban residents currently control ~22 (12-40 % of the land carbon uptake (112 PgC/yr and ~24 (15-39 % of the carbon emissions (117 PgC/yr from land globally. Urbanization resulted in the creation of new carbon pools on land such as buildings (~6.7 PgC and landfills (~30 PgC. Together these pools store 1.6 (±0.3 % of the total vegetation and soil carbon pools globally. The creation and maintenance of these new pools has been associated with high emissions of CO2, which are currently better understood than the processes associated with the dynamics of these pools and accompanying uptake of carbon. Predictions of the future trajectories of the global carbon cycle will require a much better understanding of how urban development affects the carbon cycle over the long term.

  13. Carbon accumulation in European forests: among evidences and uncertainties

    Directory of Open Access Journals (Sweden)

    Ripullone F

    2008-09-01

    Full Text Available A summary on findings recently published on Nature Geoscience (Ciais et al. 2008 is provided. This research, according with the latest studies, confirms the trend of European forests to form a sink of carbon. The sustained accumulation of carbon may result from the combined positive effects of the new favourable environmental conditions and changed forest management in the last five decades. Although this result seems encouragingly, numerous uncertainties still remain on the estimate, on the determinant processes and on the capacity that positive carbon balance could be maintained in the future. For example an increase of renewable energies demand by 2020, as proposed by EU, should double the wood demand for biomass energy, lowering considerably the carbon gains achieved in the last fifty years.

  14. Belowground carbon trade among tall trees in a temperate forest.

    Science.gov (United States)

    Klein, Tamir; Siegwolf, Rolf T W; Körner, Christian

    2016-04-15

    Forest trees compete for light and soil resources, but photoassimilates, once produced in the foliage, are not considered to be exchanged between individuals. Applying stable carbon isotope labeling at the canopy scale, we show that carbon assimilated by 40-meter-tall spruce is traded over to neighboring beech, larch, and pine via overlapping root spheres. Isotope mixing signals indicate that the interspecific, bidirectional transfer, assisted by common ectomycorrhiza networks, accounted for 40% of the fine root carbon (about 280 kilograms per hectare per year tree-to-tree transfer). Although competition for resources is commonly considered as the dominant tree-to-tree interaction in forests, trees may interact in more complex ways, including substantial carbon exchange.

  15. Carbon dynamics in the future forest: the importance of long-term successional legacy and climate-fire interactions.

    Science.gov (United States)

    Loudermilk, E Louise; Scheller, Robert M; Weisberg, Peter J; Yang, Jian; Dilts, Thomas E; Karam, Sarah L; Skinner, Carl

    2013-11-01

    Understanding how climate change may influence forest carbon (C) budgets requires knowledge of forest growth relationships with regional climate, long-term forest succession, and past and future disturbances, such as wildfires and timber harvesting events. We used a landscape-scale model of forest succession, wildfire, and C dynamics (LANDIS-II) to evaluate the effects of a changing climate (A2 and B1 IPCC emissions; Geophysical Fluid Dynamics Laboratory General Circulation Models) on total forest C, tree species composition, and wildfire dynamics in the Lake Tahoe Basin, California, and Nevada. The independent effects of temperature and precipitation were assessed within and among climate models. Results highlight the importance of modeling forest succession and stand development processes at the landscape scale for understanding the C cycle. Due primarily to landscape legacy effects of historic logging of the Comstock Era in the late 1880s, C sequestration may continue throughout the current century, and the forest will remain a C sink (Net Ecosystem Carbon Balance > 0), regardless of climate regime. Climate change caused increases in temperatures limited simulated C sequestration potential because of augmented fire activity and reduced establishment ability of subalpine and upper montane trees. Higher temperatures influenced forest response more than reduced precipitation. As the forest reached its potential steady state, the forest could become C neutral or a C source, and climate change could accelerate this transition. The future of forest ecosystem C cycling in many forested systems worldwide may depend more on major disturbances and landscape legacies related to land use than on projected climate change alone.

  16. Changes in the use and management of forests for abating carbon emissions: issues and challenges under the Kyoto Protocol.

    Science.gov (United States)

    Brown, Sandra; Swingland, Ian R; Hanbury-Tenison, Robin; Prance, Ghillean T; Myers, Norman

    2002-08-15

    The global carbon cycle is significantly influenced by changes in the use and management of forests and agriculture. Humans have the potential through changes in land use and management to alter the magnitude of forest-carbon stocks and the direction of forest-carbon fluxes. However, controversy over the use of biological means to absorb or reduce emissions of CO(2) (often referred to as carbon 'sinks') has arisen in the context of the Kyoto Protocol. The controversy is based primarily on two arguments: sinks may allow developed nations to delay or avoid actions to reduce fossil fuel emissions, and the technical and operational difficulties are too threatening to the successful implementation of land use and forestry projects for providing carbon offsets. Here we discuss the importance of including carbon sinks in efforts to address global warming and the consequent additional social, environmental and economic benefits to host countries. Activities in tropical forest lands provide the lowest cost methods both of reducing emissions and reducing atmospheric concentrations of greenhouse gases. We conclude that the various objections raised as to the inclusion of carbon sinks to ameliorate climate change can be addressed by existing techniques and technology. Carbon sinks provide a practical available method of achieving meaningful reductions in atmospheric concentrations of carbon dioxide while at the same time contribute to national sustainable development goals.

  17. Carbon stocks and dynamics at different successional stages in an Afromontane tropical forest

    Science.gov (United States)

    Nyirambangutse, Brigitte; Zibera, Etienne; Uwizeye, Félicien K.; Nsabimana, Donat; Bizuru, Elias; Pleijel, Håkan; Uddling, Johan; Wallin, Göran

    2017-03-01

    As a result of different types of disturbance, forests are a mixture of stands at different stages of ecological succession. Successional stage is likely to influence forest productivity and carbon storage, linking the degree of forest disturbance to the global carbon cycle and climate. Although tropical montane forests are an important part of tropical forest ecosystems (ca. 8 %, elevation > 1000 m a.s.l.), there are still significant knowledge gaps regarding the carbon dynamics and stocks of these forests, and how these differ between early (ES) and late successional (LS) stages. This study examines the carbon (C) stock, relative growth rate (RGR) and net primary production (NPP) of ES and LS forest stands in an Afromontane tropical rainforest using data from inventories of quantitatively important ecosystem compartments in fifteen 0.5 ha plots in Nyungwe National Park in Rwanda. The total C stock was 35 % larger in LS compared to ES plots due to significantly larger above-ground biomass (AGB; 185 and 76 Mg C ha-1 in LS and ES plots), while the soil and root C stock (down to 45 cm depth in the mineral soil) did not significantly differ between the two successional stages (178 and 204 Mg C ha-1 in LS and ES plots). The main reasons for the difference in AGB were that ES trees had significantly lower stature and wood density compared to LS trees. However, ES and LS stands had similar total NPP (canopy, wood and roots of all plots ˜ 9.4 Mg C ha-1) due to counterbalancing effects of differences in AGB (higher in LS stands) and RGR (higher in ES stands). The AGB in the LS plots was considerably higher than the average value reported for old-growth tropical montane forest of south-east Asia and Central and South America at similar elevations and temperatures, and of the same magnitude as in tropical lowland forest of these regions. The results of this study highlight the importance of accounting for disturbance regimes and differences in wood density and allometry of

  18. Implication of Forest-Savanna Dynamics on Biomass and Carbon Stock: Effectiveness of an Amazonian Ecological Station

    Science.gov (United States)

    Couto-Santos, F. R.; Luizao, F. J.

    2014-12-01

    The forests-savanna advancement/retraction process seems to play an important role in the global carbon cycle and in the climate-vegetation balance maintenance in the Amazon. To contribute with long term carbon dynamics and assess effectiveness of a protected area in reduce carbon emissions in Brazilian Amazon transitional areas, variations in forest-savanna mosaics biomass and carbon stock within Maraca Ecological Station (MES), Roraima/Brazil, and its outskirts non-protected areas were compared. Composite surface soil samples and indirect methods based on regression models were used to estimate aboveground tree biomass accumulation and assess vegetation and soil carbon stock along eleven 0.6 ha transects perpendicular to the forest-savanna limits. Aboveground biomass and carbon accumulation were influenced by vegetation structure, showing higher values within protected area, with great contribution of trees above 40 cm in diameter. In the savanna environments of protected areas, a higher tree density and carbon stock up to 30 m from the border confirmed a forest encroachment. This pointed that MES acts as carbon sink, even under variations in soil fertility gradient, with a potential increase of the total carbon stock from 9 to 150 Mg C ha-1. Under 20 years of fire and disturbance management, the results indicated the effectiveness of this protected area to reduce carbon emissions and mitigate greenhouse and climate change effects in a forest-savanna transitional area in Brazilian Northern Amazon. The contribution of this study in understanding rates and reasons for biomass and carbon variation, under different management strategies, should be considered the first approximation to assist policies of reducing emissions from deforestation and forest degradation (REDD) from underresearched Amazonian ecotone; despite further efforts in this direction are still needed. FINANCIAL SUPPORT: Boticário Group Foundation (Fundação Grupo Boticário); National Council for

  19. Temporal dynamics and sPatial variations of forest vegetation carbon stock in Liaoning Province, China

    Institute of Scientific and Technical Information of China (English)

    LI Qing; TANG Li-Na; REN Yin

    2011-01-01

    There are many uncertainties in the estimation of forest carbon sequestration in China,especially in Liaoning Province where various forest inventory data have not been fully utilized.By using forest inventory data,we estimated forest vegetation carbon stock of Liaoning Province between 1993 and 2005.Results showed that forest biomass carbon stock increased from 68.91 Tg C in 1993 to 97.51 Tg C in 2005,whereas mean carbon density increased from 18.48 Mg.ha-1 C to 22.33 Mg·ha-1 C.The carbon storage of young- and middle-aged forests increased by 22.1 Tg C and 5.95 Tg C,but that of mature forests has decreased by 0.25 Tg C.The carbon stock and density of forests in Liaoning Province varied greatly in space:larger carbon storage and higher carbon density were primarily found in the east area.The spatial distribution of carbon density was determined by many factors,of which human activities played an important role.The forests in Liauning Province played a positive role as a sink of atmospheric carbon dioxide.The carbun fixation ability of forests in this area was primarily derived from forest plantation and the total forest carbon sequestration can be enhanced by expanding young- and middle-aged forests.

  20. Forest carbon sinks in the northern hemisphere

    NARCIS (Netherlands)

    Goodale, C.L.; Apps, M.J.; Birdsey, R.A.; Field, C.B.; Heath, L.S.; Houghton, R.A.; Jenkins, J.C.; Kohlmaier, G.H.; Kurz, W.; Liu, S.R.; Nabuurs, G.J.; Nilsson, S.; Shvidenko, A.Z.

    2002-01-01

    There is general agreement that terrestrial systems in the Northern Hemisphere provide a significant sink for atmospheric CO2; however, estimates of the magnitude and distribution of this sink vary greatly. National forest inventories provide strong, measuretment-based constraints on the magnitude o

  1. Soil Organic Carbon Responses to Forest Expansion on Mountain Grasslands

    DEFF Research Database (Denmark)

    Guidi, Claudia

    Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties ...... grasslands, which can be explained by lower accumulation of binding agents of microbial origin. This can have implications for the accumulation of atmospheric CO2 in soil and for the susceptibility of SOC to external disturbances such as management and environmental changes.......Grassland abandonment followed by progressive forest expansion is the dominant land-use change in the European Alps. Contrasting trends in soil organic carbon (SOC) stocks have been reported for mountainous regions following forest expansion on grasslands. Moreover, its effects on SOC properties...... involved into long-term stability are largely unknown. The aim of this PhD thesis was to explore changes in: (i) SOC stocks; (ii) physical SOC fractions; and (iii) labile soil carbon components following forest expansion on mountain grasslands. A land-use gradient located in the Southern Alps (Italy...

  2. Impacts of tropical cyclones on U.S. forest tree mortality and carbon flux from 1851 to 2000.

    Science.gov (United States)

    Zeng, Hongcheng; Chambers, Jeffrey Q; Negrón-Juárez, Robinson I; Hurtt, George C; Baker, David B; Powell, Mark D

    2009-05-12

    Tropical cyclones cause extensive tree mortality and damage to forested ecosystems. A number of patterns in tropical cyclone frequency and intensity have been identified. There exist, however, few studies on the dynamic impacts of historical tropical cyclones at a continental scale. Here, we synthesized field measurements, satellite image analyses, and empirical models to evaluate forest and carbon cycle impacts for historical tropical cyclones from 1851 to 2000 over the continental U.S. Results demonstrated an average of 97 million trees affected each year over the entire United States, with a 53-Tg annual biomass loss, and an average carbon release of 25 Tg y(-1). Over the period 1980-1990, released CO(2) potentially offset the carbon sink in forest trees by 9-18% over the entire United States. U.S. forests also experienced twice the impact before 1900 than after 1900 because of more active tropical cyclones and a larger extent of forested areas. Forest impacts were primarily located in Gulf Coast areas, particularly southern Texas and Louisiana and south Florida, while significant impacts also occurred in eastern North Carolina. Results serve as an important baseline for evaluating how potential future changes in hurricane frequency and intensity will impact forest tree mortality and carbon balance.

  3. Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere

    Science.gov (United States)

    Ram Oren; David S. Ellsworth; Kurt H. Johnsen; Nathan Phillips; Brent E. Ewers; Chris Maier; Karina V.R. Schafer; Heather McCarthy; George Hendrey; Steven G. McNulty; Gabriel G. Katul

    2001-01-01

    Northern mid-latitude forests are a large terrestrial carbon sink. Ignoring nutrient limitations, large increases in carbon sequestration from carbon dioxide (CO2) fertilization are expected in these forests. Yet, forests are usually relegated to sites of moderate to poor fertility, where tree growth is often limited by nutrient supply, in...

  4. Magnitude and Carbon Consequences of Forest Management in North America

    Science.gov (United States)

    Masek, J.; Kurz, W.; de Jong, B. H.

    2009-12-01

    The carbon balance of forests depends on the type, frequency and severity of recent disturbances (carbon source) and the rate of recovery from past disturbance (carbon sink). Harvest and land cover conversion represent significant forest disturbance agents over much of North America. For example, pine forests in the southeastern US are typically harvested at ~20 year intervals, and may occupy about half the regional landscape, resulting in regional landscape turnover rates of 2-3% per year. Inventory data are the primary source for quantifying information on harvest and conversion in the U.S., Mexico, and Canada. Recent inventory data from these countries indicate timber production of 424 million cu m, 163 million cu m, and 7 million cu m, respectively, with significant year-to-year variability associated with wood products demand and timber price. Areas affected by harvest activity vary as well, with 3.97 Mha (million hectares) and 1.04 Mha affected by harvest in the US and Canada, respectively. Forest cover conversion (deforestation) is thought to be relatively minor in the US and Canada, but recent estimates suggest that forest and woodland cover in Mexico declined by 300-500 Kha/yr during the 1990’s. Recently, satellite remote sensing data products on forest change have been generated that complement the traditional inventory approach. These products are particularly useful for “wall-to-wall” estimates of forest conversion and tracking small disturbances. The type and severity of disturbance cannot be easily determined using satellite observations, however, and therefore some care must be taken to reconcile these products with ground-based data. In this talk we review available resources for characterizing “carbon relevant” information on the magnitude (area, type of activity) of forest management in North America, and attempt a first-order comparison between remote sensing and inventory estimates. We also discuss strategies that might be employed to

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

    Science.gov (United States)

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

    2015-02-01

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

  6. Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts.

    Science.gov (United States)

    Frank, Dorothea; Reichstein, Markus; Bahn, Michael; Thonicke, Kirsten; Frank, David; Mahecha, Miguel D; Smith, Pete; van der Velde, Marijn; Vicca, Sara; Babst, Flurin; Beer, Christian; Buchmann, Nina; Canadell, Josep G; Ciais, Philippe; Cramer, Wolfgang; Ibrom, Andreas; Miglietta, Franco; Poulter, Ben; Rammig, Anja; Seneviratne, Sonia I; Walz, Ariane; Wattenbach, Martin; Zavala, Miguel A; Zscheischler, Jakob

    2015-08-01

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global

  7. Vegetation change impacts on soil organic carbon chemical composition in subtropical forests

    Science.gov (United States)

    Guo, Xiaoping; Meng, Miaojing; Zhang, Jinchi; Chen, Han Y. H.

    2016-07-01

    Changes in the chemical composition of soil organic carbon (SOC) might strongly affect the global carbon cycle as it controls the SOC decomposition rate. Vegetation change associated with long-term land use changes is known to strongly impact the chemical composition of SOC; however, data on the impacts of vegetation change following disturbance events of short durations and succession that occur frequently in forest ecosystems via diverse management objectives on SOC chemical composition are negligible. Here we examined the impacts of vegetation changes on the chemical composition of SOC by sampling soils of native broad-leaved forests, planted mixed broad-leaved and coniferous forests, and tea gardens in eastern China. We used nuclear magnetic resonance spectroscopy to quantify SOC chemical composition. We found that among all components of SOC chemical composition, alkyl carbon (C) and aryl C were more liable to change with vegetation than other SOC components. Soil pH was negatively correlated to the relative abundances of alkyl C and N-alkyl C, and Shannon’s index of overstory plant species was positively correlated to the relative abundances of phenolic C and aromaticity. Our results suggest that vegetation changes following short disturbance events and succession may strongly alter SOC chemical composition in forest ecosystems.

  8. Carbon exchange between the atmosphere and subtropical forested cypress and pine wetlands

    Science.gov (United States)

    Shoemaker, W. Barclay; Anderson, Frank E.; Barr, Jordan G.; Graham, Scott L.; Botkin, Daniel B.

    2015-01-01

    Carbon dioxide exchange between the atmosphere and forested subtropical wetlands is largely unknown. Here we report a first step in characterizing this atmospheric–ecosystem carbon (C) exchange, for cypress strands and pine forests in the Greater Everglades of Florida as measured with eddy covariance methods at three locations (Cypress Swamp, Dwarf Cypress and Pine Upland) for 2 years. Links between water and C cycles are also examined at these three sites, as are methane emission measured only at the Dwarf Cypress site. Each forested wetland showed net C uptake from the atmosphere both monthly and annually, as indicated by the net ecosystem exchange (NEE) of carbon dioxide (CO2). For this study, NEE is the difference between photosynthesis and respiration, with negative values representing uptake from the atmosphere that is retained in the ecosystem or transported laterally via overland flow (unmeasured for this study). Atmospheric C uptake (NEE) was greatest at the Cypress Swampp (−900 to −1000 g C m2 yr−1), moderate at the Pine Upland (−650 to −700 g C m2 yr−1) and least at the Dwarf Cypress (−400 to −450 g C m2 yr−1). Changes in NEE were clearly a function of seasonality in solar insolation, air temperature and flooding, which suppressed heterotrophic soil respiration. We also note that changes in the satellite-derived enhanced vegetation index (EVI) served as a useful surrogate for changes in NEE at these forested wetland sites.

  9. Belowground carbon flux links biogeochemical cycles and resource-use efficiency at the global scale.

    Science.gov (United States)

    Gill, Allison L; Finzi, Adrien C

    2016-12-01

    Nutrient limitation is pervasive in the terrestrial biosphere, although the relationship between global carbon (C) nitrogen (N) and phosphorus (P) cycles remains uncertain. Using meta-analysis we show that gross primary production (GPP) partitioning belowground is inversely related to soil-available N : P, increasing with latitude from tropical to boreal forests. N-use efficiency is highest in boreal forests, and P-use efficiency in tropical forests. High C partitioning belowground in boreal forests reflects a 13-fold greater C cost of N acquisition compared to the tropics. By contrast, the C cost of P acquisition varies only 2-fold among biomes. This analysis suggests a new hypothesis that the primary limitation on productivity in forested ecosystems transitions from belowground resources at high latitudes to aboveground resources at low latitudes as C-intensive root- and mycorrhizal-mediated nutrient capture is progressively replaced by rapidly cycling, enzyme-derived nutrient fluxes when temperatures approach the thermal optimum for biogeochemical transformations. © 2016 John Wiley & Sons Ltd/CNRS.

  10. Final Technical Report. Supporting carbon cycle and earth systems modeling with measurements and analysis from the Howland AmeriFlux Site

    Energy Technology Data Exchange (ETDEWEB)

    Hollinger, David [USDA Forest Service, Washington, DC (United States); Davidson, E. [Woods Hole Research Center, Falmouth, MA (United States); Dail, D. B. [Univ. of Maine, Orono, ME (United States); Richardson, A. [Harvard Univ., Cambridge, MA (United States)

    2016-01-11

    This report provides and overview of the work carried out and lists the products produced under the terms of agreement SC0005578 with the USDA Forest Service. This relates to scientific investigation of the carbon cycle at the Howland Forest AmeriFlux site located in central Maine, USDA. The overall goal of this work was to understand the various (and interacting) impacts of a changing climate on carbon cycling at the Howland AmeriFlux site, representative of an important component of the North American boreal forest.

  11. Where did the US forest biomass/carbon go?

    Science.gov (United States)

    Christopher William. Woodall

    2012-01-01

    In Apr. 2012, with the submission of the 1990-2010 US Greenhouse Gas (GHG) Inventory to the United Nations Framework Convention on Climate Change (UNFCCC), the official estimates of aboveground live tree carbon stocks within managed forests of the United States will drop by approximately 14%, compared with last year's inventory. It does not stop there, dead wood...

  12. Site Productivity and Forest Carbon Stocks in the United States: Analysis and Implications for Forest Offset Project Planning

    Directory of Open Access Journals (Sweden)

    James E. Smith

    2012-06-01

    Full Text Available The documented role of United States forests in sequestering carbon, the relatively low cost of forest-based mitigation, and the many co-benefits of increasing forest carbon stocks all contribute to the ongoing trend in the establishment of forest-based carbon offset projects. We present a broad analysis of forest inventory data using site quality indicators to provide guidance to managers planning land acquisition for forest-based greenhouse gas mitigation projects. Specifically, we summarize two condition class indicators of site productivity within the FIA forest inventory database—physclcd and siteclcd—as they relate to current aboveground live tree carbon stocks. Average carbon density is higher on more productive sites, but compared to the overall variability among sites, the differences are relatively small for all but the highest and lowest site classes. Some minor differences in eastern- versus western-forests were apparent in terms of how carbon on the least productive sites differed from most other forest land over time. Overall results suggest that xeric sites in most regions as well as sites that correspond to the lowest, non-productive classifications of forest land should preferentially not be used forestry-based greenhouse gas mitigation projects, but all other forest areas appear to be suitable.

  13. Effect of Forest Fire on Regional Carbon Dioxide Exchange Over Boreal Forest in Interior Alaska

    Science.gov (United States)

    Iwata, H.; Otsuki, M.; Harazono, Y.; Ueyama, M.; Iwata, T.

    2010-12-01

    Forest fire is a major disturbance in boreal forest ecosystems and significantly influences carbon exchange processes by combustion of vegetation and surface organic soils. In Interior Alaska, area of 7.6x106 ha was burned during 2000-2009 by forest fires. Fire occurrence frequency in the next decade may increase with current warming trend. Hence, it is important to include carbon dioxide (CO2) exchange at fire scars to accurately estimate regional CO2 exchange. To quantify CO2 exchange, CO2 flux and meteorological data were obtained at an undisturbed black spruce forest and a fire scar (five years after fire) in Interior Alaska, and responses of photosynthesis and respiration to meteorological variables were examined in each site. Photosynthesis at the fire scar was reduced to approximately 50 % of photosynthesis at the undisturbed black spruce forest due to loss of vegetation. Respiration at the fire scar was also reduced to 50 % of the undisturbed black spruce forest. This is attributable to decrease of biomass and surface organic matter. Annual net exchanges of CO2 at both sites were uptake of 519 and 256 gCO2/m2/year for the undisturbed black spruce forest and the fire scar, respectively. We used light-use efficiency model to estimate spatial distributions of photosynthesis and respiration using remote sensing imagery, NCEP/NCAR reanalysis meteorology and NASA solar radiation. The model was parameterized using observations at the undisturbed black spruce forest and the fire scar. Estimated regional average of CO2 uptake was reduced by 10 % compared to an estimated value with which fire scars were not included. Further improvement is expected by incorporating severity of forest fires that determine reduction of photosynthesis and respiration after fires.

  14. Comparative Study of Carbon Storage and Allocation Characteristics of Mature Evergreen Broad-leaved Forest

    Institute of Scientific and Technical Information of China (English)

    Zhangquan; ZENG; Canming; ZHANGY; Yandong; NIU; Xiquan; LI; Zijian; WU; Jia; LUO

    2014-01-01

    Evergreen broad-leaved forest is an important forest type in China.This paper analyzes the allocation characteristics of vegetation and soil carbon pool of evergreen broad-leaved forest,to understand the current status of research on the carbon storage of evergreen broadleaved forest as well as shortcomings.In the context of global climate change,it is necessary to carry out the long-term research of evergreen broad-leaved forest,in order to grasp the formation mechanism of evergreen broad-leaved forest productivity,and the impact of climate change on the carbon sequestration function of evergreen broad-leaved forest ecosystem.

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

    Science.gov (United States)

    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

  16. The Role of Carbon Cycle Observations and Knowledge in Carbon Management

    Energy Technology Data Exchange (ETDEWEB)

    Dilling, Lisa; Doney, Scott; Edmonds, James A.; Gurney, Kevin R.; Harriss, Robert; Schimel, David; Stephens, Britton; Stokes, Gerald M.

    2003-08-14

    Agriculture and industrial development have led to inadvertent changes in the natural carbon cycle. As a consequence, concentrations of carbon dioxide and other greenhouse gases have increased in the atmosphere, leading to potential changes in climate. The current challenge facing society is to develop options for future management of the carbon cycle. A variety of approaches has been suggested: direct reduction of emissions, deliberate manipulation of the natural carbon cycle to enhance sequestration, and capture and isolation of carbon from fossil fuel use. Policy development to date has laid out some of the general principles to which carbon management should adhere. These can be summarized as: how much carbon is stored, by what means, and for how long. To successfully manage carbon for climate purposes requires increased understanding of carbon cycle dynamics and improvement to the scientific capabilities available for measurement as well as policy needs. Specific needs for scientific information to underpin carbon cycle management decisions are not yet broadly known. A stronger dialogue between decision makers and scientists must be developed to foster improved application of scientific knowledge to decisions. This paper reviews the current state of knowledge of the carbon cycle and measurement capabilities, with an emphasis on the continental-scale, and its relevance to carbon sequestration goals.

  17. Holocene carbon dynamics at the forest-steppe ecotone of southern Siberia.

    Science.gov (United States)

    Mackay, Anson William; Seddon, Alistair W R; Leng, Melanie J; Heumann, Georg; Morley, David W; Piotrowska, Natalia; Rioual, Patrick; Roberts, Sarah; Swann, George E A

    2016-12-09

    The forest-steppe ecotone in southern Siberia is highly sensitive to climate change; global warming is expected to push the ecotone northwards, at the same time resulting in degradation of the underlying permafrost. To gain a deeper understanding of long-term forest-steppe carbon dynamics, we use a highly resolved, multiproxy, palaeolimnological approach, based on sediment records from Lake Baikal. We reconstruct proxies that are relevant to understanding carbon dynamics including carbon mass accumulation rates (CMAR; g C m(-2)  yr(-1) ) and isotope composition of organic matter (δ(13) CTOC ). Forest-steppe dynamics were reconstructed using pollen, and diatom records provided measures of primary production from near- and off-shore communities. We used a generalized additive model (GAM) to identify significant change points in temporal series, and by applying generalized linear least-squares regression modelling to components of the multiproxy data, we address (1) What factors influence carbon dynamics during early Holocene warming and late Holocene cooling? (2) How did carbon dynamics respond to abrupt sub-Milankovitch scale events? and (3) What is the Holocene carbon storage budget for Lake Baikal. CMAR values range between 2.8 and 12.5 g C m(-2)  yr(-1) . Peak burial rates (and greatest variability) occurred during the early Holocene, associated with melting permafrost and retreating glaciers, while lowest burial rates occurred during the neoglacial. Significant shifts in carbon dynamics at 10.3, 4.1 and 2.8 kyr bp provide compelling evidence for the sensitivity of the region to sub-Milankovitch drivers of climate change. We estimate that 1.03 Pg C was buried in Lake Baikal sediments during the Holocene, almost one-quarter of which was buried during the early Holocene alone. Combined, our results highlight the importance of understanding the close linkages between carbon cycling and hydrological processes, not just temperatures, in southern Siberian

  18. Cross-continental comparison of the functional composition and carbon allocation of two altitudinal forest transects in Ecuador and Rwanda.

    Science.gov (United States)

    Verbeeck, Hans; Bauters, Marijn; Bruneel, Stijn; Demol, Miro; Taveirne, Cys; Van Der Heyden, Dries; Kearsley, Elizabeth; Cizungu, Landry; Boeckx, Pascal

    2017-04-01

    Tropical forests are key actors in the global carbon cycle. Predicting future responses of these forests to global change is challenging, but important for global climate models. However, our current understanding of such responses is limited, due to the complexity of forest ecosystems and the slow dynamics that inherently form these systems. Our understanding of ecosystem ecology and functioning could greatly benefit from experimental setups including strong environmental gradients in the tropics, as found on altitudinal transects. We setup two such transects in both South-America and Central Africa, focussing on shifts in carbon allocation, forest structure, nutrient cycling and functional composition. The Ecuadorian transect has 16 plots (40 by 40 m) and ranges from 400 to 3000 m.a.s.l., and the Rwandan transect has 20 plots (40 by 40 m) from 1500 to 3000 m.a.s.l. All plots were inventoried and canopy, litter and soil were extensively sampled. By a cross-continental comparison of both transects, we will gain insight in how different or alike both tropical forests biomes are in their responses, and how universal the observed altitudinal adaption mechanisms are. This could provide us with vital information of the ecological responses of both biomes to future global change scenarios. Additionally, comparison of nutrient shifts and trait-based functional composition allows us to compare the biogeochemical cycles of African and South-American tropical forests.

  19. Review of study on mineralization, saturation and cycle of Nitrogen in forest ecosystems

    Institute of Scientific and Technical Information of China (English)

    YANG Jin-yan; FAN Jing

    2003-01-01

    Nitrogen is one of the most important elements that can limit plant growth in forest ecosystems. Studies of nitrogen mineralization, nitrogen saturation and nitrogen cycle in forest ecosystems is very necessary for understanding the productivity of stand, nutrient cycle and turnover of nitrogen of forest ecosystems. Based on comparison and analysis of domestic and international academic references related to studies on nitrogen mineralization, nitrogen saturation and nitrogen cycle in recent 10 years, the current situation and development of the study on these aspects, and the problems existed in current researches were reviewed. At last, some advices were given for future researches.

  20. Carbon pool densities and a first estimate of the total carbon pool in the Mongolian forest-steppe.

    Science.gov (United States)

    Dulamsuren, Choimaa; Klinge, Michael; Degener, Jan; Khishigjargal, Mookhor; Chenlemuge, Tselmeg; Bat-Enerel, Banzragch; Yeruult, Yolk; Saindovdon, Davaadorj; Ganbaatar, Kherlenchimeg; Tsogtbaatar, Jamsran; Leuschner, Christoph; Hauck, Markus

    2016-02-01

    The boreal forest biome represents one of the most important terrestrial carbon stores, which gave reason to intensive research on carbon stock densities. However, such an analysis does not yet exist for the southernmost Eurosiberian boreal forests in Inner Asia. Most of these forests are located in the Mongolian forest-steppe, which is largely dominated by Larix sibirica. We quantified the carbon stock density and total carbon pool of Mongolia's boreal forests and adjacent grasslands and draw conclusions on possible future change. Mean aboveground carbon stock density in the interior of L. sibirica forests was 66 Mg C ha(-1) , which is in the upper range of values reported from boreal forests and probably due to the comparably long growing season. The density of soil organic carbon (SOC, 108 Mg C ha(-1) ) and total belowground carbon density (149 Mg C ha(-1) ) are at the lower end of the range known from boreal forests, which might be the result of higher soil temperatures and a thinner permafrost layer than in the central and northern boreal forest belt. Land use effects are especially relevant at forest edges, where mean carbon stock density was 188 Mg C ha(-1) , compared with 215 Mg C ha(-1) in the forest interior. Carbon stock density in grasslands was 144 Mg C ha(-1) . Analysis of satellite imagery of the highly fragmented forest area in the forest-steppe zone showed that Mongolia's total boreal forest area is currently 73 818 km(2) , and 22% of this area refers to forest edges (defined as the first 30 m from the edge). The total forest carbon pool of Mongolia was estimated at ~ 1.5-1.7 Pg C, a value which is likely to decrease in future with increasing deforestation and fire frequency, and global warming.

  1. Glassy carbon supercapacitor: 100,000 cycles demonstrated

    Energy Technology Data Exchange (ETDEWEB)

    Baertsch, M.; Braun, A.; Schnyder, B.; Koetz, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    A 5 V glassy carbon capacitor stack was built consisting of four bipolar and two end-plate electrodes. More than 100,000 charging/discharging cycles were applied to test the stability of the double-layer capacitor. Low and high frequency resistances were measured as a function of the number of cycles. (author) 2 figs., 1 ref.

  2. Carbon cycle observations: gaps threaten climate mitigation policies

    Science.gov (United States)

    Richard Birdsey; Nick Bates; MIke Behrenfeld; Kenneth Davis; Scott C. Doney; Richard Feely; Dennis Hansell; Linda Heath; et al.

    2009-01-01

    Successful management of carbon dioxide (CO2) requires robust and sustained carbon cycle observations. Yet key elements of a national observation network are lacking or at risk. A U.S. National Research Council review of the U.S. Climate Change Science Program earlier this year highlighted the critical need for a U.S. climate observing system to...

  3. Interglacials, Milankovitch Cycles, Solar Activity, and Carbon Dioxide

    Directory of Open Access Journals (Sweden)

    Gerald E. Marsh

    2014-01-01

    Full Text Available The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent work challenges the fundamental basis of these conceptions.

  4. Interglacials, Milankovitch Cycles, Solar Activity, and Carbon Dioxide

    OpenAIRE

    Marsh, Gerald E.

    2014-01-01

    The existing understanding of interglacial periods is that they are initiated by Milankovitch cycles enhanced by rising atmospheric carbon dioxide concentrations. During interglacials, global temperature is also believed to be primarily controlled by carbon dioxide concentrations, modulated by internal processes such as the Pacific Decadal Oscillation and the North Atlantic Oscillation. Recent work challenges the fundamental basis of these conceptions.

  5. Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

    Science.gov (United States)

    Hommeltenberg, J.; Schmid, H. P.; Drösler, M.; Werle, P.

    2014-07-01

    This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-Alpine region of southern Germany. The sites are separated by only 10 km, they share the same soil formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo ssp. rotundata) grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies) grows on drained and degraded peat (3.4 m). The net ecosystem exchange of CO2 (NEE) at both sites has been investigated for 2 years (July 2010-June 2012), using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (-130 ± 31 and -300 ± 66 g C m-2 a-1 in the first and second year, respectively) than the natural bog forest at Schechenfilz (-53 ± 28 and -73 ± 38 g C m-2 a-1). The strong net CO2 uptake can be explained by the high gross primary productivity of the 44-year old spruces that over-compensates the two-times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger plant area index (PAI) of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source when the whole life-cycle since forest planting is considered. It is important to access this result in terms of the long-term biome balance. To do so, we used historical data to estimate the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. This rough estimate indicates a strong carbon release of +134 t C ha-1 within the last 44 years. Thus, the spruces would need to grow for another 100 years at about the current rate, to compensate the potential peat loss of the former years. In

  6. Can a bog drained for forestry be a stronger carbon sink than a natural bog forest?

    Directory of Open Access Journals (Sweden)

    J. Hommeltenberg

    2014-02-01

    Full Text Available This study compares the CO2 exchange of a natural bog forest, and of a bog drained for forestry in the pre-alpine region of southern Germany. The sites are separated by only ten kilometers, they share the same formation history and are exposed to the same climate and weather conditions. In contrast, they differ in land use history: at the Schechenfilz site a natural bog-pine forest (Pinus mugo rotundata grows on an undisturbed, about 5 m thick peat layer; at Mooseurach a planted spruce forest (Picea abies grows on drained and degraded peat (3.4 m. The net ecosystem exchange of CO2 (NEE at both sites has been investigated for two years (July 2010 to June 2012, using the eddy covariance technique. Our results indicate that the drained, forested bog at Mooseurach is a much stronger carbon dioxide sink (−130 ± 31 and −300 ± 66 g C m−2 a−1 in the first and second year respectively than the natural bog forest at Schechenfilz (−53 ± 28 and −73±38 g C m−2 a−1. The strong net CO2 uptake can be explained by the high gross primary productivity of the spruces that over-compensates the two times stronger ecosystem respiration at the drained site. The larger productivity of the spruces can be clearly attributed to the larger LAI of the spruce site. However, even though current flux measurements indicate strong CO2 uptake of the drained spruce forest, the site is a strong net CO2 source, if the whole life-cycle, since forest planting is considered. We determined the difference between carbon fixation by the spruces and the carbon loss from the peat due to drainage since forest planting. The estimate resulted in a strong carbon release of +156 t C ha−1 within the last 44 yr, means the spruces would need to grow for another 100 yr, at the current rate, to compensate the peat loss of the former years. In contrast, the natural bog-pine ecosystem has likely been a small but consistent carbon sink for decades, which our results suggest is very

  7. The Importance of Uncertainty and Sensitivity Analysis in Process-based Models of Carbon and Nitrogen Cycling in Terrestrial Ecosystems with Particular Emphasis on Forest Ecosystems — Selected Papers from a Workshop Organized by the International Society for Ecological Modelling (ISEM) at the Third Biennal Meeting of the International Environmental Modelling and Software Society (IEMSS) in Burlington, Vermont, USA, August 9-13, 2006

    Science.gov (United States)

    Larocque, Guy R.; Bhatti, Jagtar S.; Liu, Jinxun; Ascough, James C.; Gordon, Andrew M.

    2008-01-01

    Many process-based models of carbon (C) and nitrogen (N) cycles have been developed for terrestrial ecosystems, including forest ecosystems. They address many basic issues of ecosystems structure and functioning, such as the role of internal feedback in ecosystem dynamics. The critical factor in these phenomena is scale, as these processes operate at scales from the minute (e.g. particulate pollution impacts on trees and other organisms) to the global (e.g. climate change). Research efforts remain important to improve the capability of such models to better represent the dynamics of terrestrial ecosystems, including the C, nutrient, (e.g. N) and water cycles. Existing models are sufficiently well advanced to help decision makers develop sustainable management policies and planning of terrestrial ecosystems, as they make realistic predictions when used appropriately. However, decision makers must be aware of their limitations by having the opportunity to evaluate the uncertainty associated with process-based models (Smith and Heath, 2001 and Allen et al., 2004). The variation in scale of issues currently being addressed by modelling efforts makes the evaluation of uncertainty a daunting task.

  8. Carbon, energy and forest biomass: new opportunities and needs for forest management in Italy

    Directory of Open Access Journals (Sweden)

    2005-01-01

    Full Text Available Forest biomass provides a relevant fraction of world energy needs, not only in developing Countries. In Italy, several factors are presently contributing to a new interest for this resource, ranging from regulatory quotas for renewables to the increasing price of fossil fuel to the emergence of a European carbon stock exchange. This focus on renewable resources constitutes an important opportunity for the forest sector and for society by and large, but because of the potential dimensions of the emerging market it also requires new planning instruments, in order to avoid a sudden and widespread resumption of coppice management and a reduction of standing carbon stock in forest ecosystems, which would run contrary to the objectives of the Kyoto Protocol. An example of the future demand for biomasses in Central Italy is presented, based on the possible use of fuelwood in new coal-fired power plants by the 'co-firing' technology.

  9. The urban forest and ecosystem services: impact on urban water, heat, and pollution cycles at the tree, street, and city scale

    Science.gov (United States)

    S. J. Livesley; E. G. McPherson; C. Calfapietra

    2016-01-01

    Many environmental challenges are exacerbated within the urban landscape, such as stormwater runoff and flood risk, chemical and particulate pollution of urban air, soil and water, the urban heat island, and summer heat waves. Urban trees, and the urban forest as a whole, can be managed to have an impact on the urban water, heat, carbon and pollution cycles. However,...

  10. Strong carbon sink of monsoon tropical seasonal forest in Southern Vietnam

    Science.gov (United States)

    Deshcherevskaya, Olga; Anichkin, Alexandr; Avilov, Vitaly; Duy Dinh, Ba; Luu Do, Phong; Huan Tran, Cong; Kurbatova, Julia

    2014-05-01

    -1, from carbon source to the strong sink. Storage total for all the year was near-zero, but in our case including of storage resulted in gap-filling regression changes with corresponding change in total carbon balance. Probably the only way for proper net carbon balance evaluation for NCT site is chamber-measurements of night respiration of different ecosystem components, as used at Pasoh EC station, Malaysia. Ciais P., Piao S.L., Cadule P., Friedlingstein P., & Chedin A. Variability and recent trends in the African carbon balance. Biogeosciences Discussions, 5(4), 2008. Pp. 3497-3532. Clark D.A. Sources or sinks? The responses of tropical forests to current and future climate and atmospheric composition. Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences, 359(1443), 2004. Pp. 477-491. Gifford, R. M. (1994). The global carbon cycle: a viewpoint on the missing sink. Functional Plant Biology, 21(1), 1-15. Kosugi Y., Takanashi S., Tani M., Ohkubo S., Matsuo N., Itoh M., Noguchi S. & Nik A.R. Effect of inter-annual climate variability on evapotranspiration and canopy CO2 exchange of a tropical rainforest in Peninsular Malaysia. Journal of forest research, 17(3), 2012. Pp. 227-240. Malhi, Y. (2010). The carbon balance of tropical forest regions, 1990-2005. Current Opinion in Environmental Sustainability, 2(4), 237-244. Saigusa, N., Yamamoto, S., Hirata, R., Ohtani, Y., Ide, R., Asanuma, J., ... & Wang, H. (2008). Temporal and spatial variations in the seasonal patterns of CO2 flux in boreal, temperate, and tropical forests in East Asia. Agricultural and forest meteorology, 148(5), 700-713.

  11. Ecosystem services of boreal forests - Carbon budget mapping at high resolution.

    Science.gov (United States)

    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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Bedrock Nitrogen Contributes to Increased Carbon Storage in Temperate Conifer Forests of Northern California, USA

    Science.gov (United States)

    Morford, S. L.; Houlton, B. Z.; Dahlgren, R. A.

    2010-12-01

    Identifying mechanisms by which nitrogen (N) enters ecosystems is crucial to modeling carbon (C) storage and earth system responses to rising CO2 emissions. Paradigms of nutrient cycling posit that N enters ecosystems solely from the atmosphere; however, rocks contain 99% of all fixed N on Earth, implying a potentially widespread source of ecologically available N. We tested the hypothesis that bedrock N contributes to increased N fertility and C storage of temperate conifer forests underlain by N-rich bedrock in northern California, USA. We used a paired sampling design to measure total N and C, and N stable isotope ratios (15N/14N) of surface mineral soils, bedrock, and foliage from similar forests that differed in parent material: the first site on N-rich (680 ppm N) metasedimentary rock, the second site on N-poor (55 ppm N) igneous rock. In addition, we performed a regional analysis of C storage in aboveground tree biomass using Forest Inventory and Analysis (FIA) plot data (n = 82) from conifer forests on N-rich and N-poor bedrock to examine for C by N interactions at the regional scale. The N content of soils and conifer needles was elevated by more than 50% in the forest underlain by N-rich bedrock, with soil C pools elevated by 60% in N-rich sites. Further, 15N/14N of rock, soils, and plants were indistinguishable in sites underlain by N-rich lithology, whereas foliar 15N/14N from N-poor site was depleted 20‰ relative to rock. Finally, the regional data pointed to substantial effects of N-rich rock on total forest C storage; ecosystem C pools were 40% higher in forests with geologic N than sites with N-poor bedrock minerals. These results suggest that rock weathering can profoundly alter ecosystem N and C cycles, implying an overlooked pathway of N input to terrestrial ecosystems.

  13. Modeling the uncertainty of estimating forest carbon stocks in China

    Directory of Open Access Journals (Sweden)

    T. X. Yue

    2015-12-01

    Full Text Available Earth surface systems are controlled by a combination of global and local factors, which cannot be understood without accounting for both the local and global components. The system dynamics cannot be recovered from the global or local controls alone. Ground forest inventory is able to accurately estimate forest carbon stocks at sample plots, but these sample plots are too sparse to support the spatial simulation of carbon stocks with required accuracy. Satellite observation is an important source of global information for the simulation of carbon stocks. Satellite remote-sensing can supply spatially continuous information about the surface of forest carbon stocks, which is impossible from ground-based investigations, but their description has considerable uncertainty. In this paper, we validated the Lund-Potsdam-Jena dynamic global vegetation model (LPJ, the Kriging method for spatial interpolation of ground sample plots and a satellite-observation-based approach as well as an approach for fusing the ground sample plots with satellite observations and an assimilation method for incorporating the ground sample plots into LPJ. The validation results indicated that both the data fusion and data assimilation approaches reduced the uncertainty of estimating carbon stocks. The data fusion had the lowest uncertainty by using an existing method for high accuracy surface modeling to fuse the ground sample plots with the satellite observations (HASM-SOA. The estimates produced with HASM-SOA were 26.1 and 28.4 % more accurate than the satellite-based approach and spatial interpolation of the sample plots, respectively. Forest carbon stocks of 7.08 Pg were estimated for China during the period from 2004 to 2008, an increase of 2.24 Pg from 1984 to 2008, using the preferred HASM-SOA method.

  14. Analysing the uncertainty of estimating forest carbon stocks in China

    Science.gov (United States)

    Yue, Tian Xiang; Wang, Yi Fu; Du, Zheng Ping; Zhao, Ming Wei; Li Zhang, Li; Zhao, Na; Lu, Ming; Larocque, Guy R.; Wilson, John P.

    2016-07-01

    Earth surface systems are controlled by a combination of global and local factors, which cannot be understood without accounting for both the local and global components. The system dynamics cannot be recovered from the global or local controls alone. Ground forest inventory is able to accurately estimate forest carbon stocks in sample plots, but these sample plots are too sparse to support the spatial simulation of carbon stocks with required accuracy. Satellite observation is an important source of global information for the simulation of carbon stocks. Satellite remote sensing can supply spatially continuous information about the surface of forest carbon stocks, which is impossible from ground-based investigations, but their description has considerable uncertainty. In this paper, we validated the Kriging method for spatial interpolation of ground sample plots and a satellite-observation-based approach as well as an approach for fusing the ground sample plots with satellite observations. The validation results indicated that the data fusion approach reduced the uncertainty of estimating carbon stocks. The data fusion had the lowest uncertainty by using an existing method for high-accuracy surface modelling to fuse the ground sample plots with the satellite observations (HASM-S). The estimates produced with HASM-S were 26.1 and 28.4 % more accurate than the satellite-based approach and spatial interpolation of the sample plots respectively. Forest carbon stocks of 7.08 Pg were estimated for China during the period from 2004 to 2008, an increase of 2.24 Pg from 1984 to 2008, using the preferred HASM-S method.

  15. Seasonal variation of carbon uptake in a primary forest ecosystem in southwestern Amazon

    Science.gov (United States)

    Garcia, S.; Gonçalves, J. F.; Cirino, G. G.; Artaxo, P.

    2013-05-01

    Tropical rainforests possess a large carbon stock and their dynamics are strongly dependent on climatic factors. Carbon assimilation by tropical forests can be meaningfully altered by seasonal changes in rainfall regime. Considering the interactions of the plant-atmosphere system, this study evaluated the effect of the precipitation seasonality on the photosynthesis of a primary forest, located in the state of Rondônia (Rebio Jaru), southwest of the Amazon, Brazil. Precipitation data from Instituto Nacional de Metereologia (INMET) from five years (2006-2010) were analyzed and the NEE (Net Ecosystem Exchange) of CO2 was calculated for ten years (1999-2009) using data from the Large Scale Biosphere-Atmosphere Experiment in the Amazon (LBA). Furthermore, leaves gas exchanges were measured in 48 individual in three forest strata (canopy, sub-canopy and understory) using a infrared gas analyzer (IRGA model LI-6400, Li-cor, USA) during two distinct precipitation periods: at the end of the wet (May) and dry (Sept.) seasons. The climatological data exhibited an accentuated dry season between the months of June and August. The lower water availability inhibited the forest primary production and altered the CO2 assimilation observed in the variation in the NEE values (Fig. 1). The NEE values were larger in the dry season and showed a smaller carbon uptake in the ecosystem, when compared with the values from the wet season. In the period that succeeds the dry season, the photosynthetic rates measured in canopy leaves were 44,49% lower than the values measured in the period prior to the dry season. Therefore, it is possible to conclude that the accentuated dry season strongly controls the seasonal photosynthesis variation in the studied area, decreasing the carbon uptake into the ecosystem. Fig. 1: Seasonal cycle of Net Ecosystem Exchange (NEE) of CO2 between the forest and atmosphere, in Rebio Jaru (1999-2009, monthly averages).

  16. Multifunctional composites using reinforced laminae with carbon-nanotube forests

    Science.gov (United States)

    Veedu, Vinod P.; Cao, Anyuan; Li, Xuesong; Ma, Kougen; Soldano, Caterina; Kar, Swastik; Ajayan, Pulickel M.; Ghasemi-Nejhad, Mehrdad N.

    2006-06-01

    Traditional fibre-reinforced composite materials with excellent in-plane properties fare poorly when out-of-plane through-thickness properties are important. Composite architectures with fibres designed orthogonal to the two-dimensional (2D) layout in traditional composites could alleviate this weakness in the transverse direction, but all of the efforts so far have only produced limited success. Here, we unveil an approach to the 3D composite challenge, without altering the 2D stack design, on the basis of the concept of interlaminar carbon-nanotube forests that would provide enhanced multifunctional properties along the thickness direction. The carbon-nanotube forests allow the fastening of adjacent plies in the 3D composite. We grow multiwalled carbon nanotubes on the surface of micro-fibre fabric cloth layouts, normal to the fibre lengths, resulting in a 3D effect between plies under loading. These nanotube-coated fabric cloths serve as building blocks for the multilayered 3D composites, with the nanotube forests providing much-needed interlaminar strength and toughness under various loading conditions. For the fabricated 3D composites with nanotube forests, we demonstrate remarkable improvements in the interlaminar fracture toughness, hardness, delamination resistance, in-plane mechanical properties, damping, thermoelastic behaviour, and thermal and electrical conductivities making these structures truly multifunctional.

  17. What Carbon Sources Support Groundwater Microbial Activity in Riparian Forests?

    Science.gov (United States)

    Gurwick, N. P.; Groffman, P. M.; McCorkle, D. C.; Stolt, M. H.; Kellogg, D. Q.; Gold, A. J.

    2004-05-01

    A major question in riparian research is the source of energy to support subsurface microbial denitrification activity. The supply of microbially-available carbon frequently limits microbial activity in the subsurface. Therefore, identifying the relative importance of carbon sources in the riparian subsurface helps explain the sustainability and spatial heterogeneity of denitrification rates. We have investigated the importance of buried, carbon-rich soil horizons, deep roots and dissolved organic carbon as potential carbon sources to support groundwater denitrification in riparian forests in Rhode Island. We used field observations, laboratory incubations and in-situ experiments to evaluate these sources at four sites in different geomorphic settings. In particular, we measured the 14C-DIC signature and DIC concentration of ambient groundwater and groundwater that had been degassed, re-introduced into the well, and incubated in-situ. Buried horizons appear to be an important source of carbon in the subsurface, as shown by active respiration in laboratory incubations; greater microbial biomass in buried carbon-rich soils compared to surrounding carbon-poor soils; and the presence of very old carbon (>1,000 ybp) in DIC 225 cm beneath the surface. DIC collected from shallower wells showed no clear evidence of ancient carbon. Roots also appear to be important, creating hotspots of carbon availability and denitrification in the generally carbon poor subsurface matrix. Dissolved organic carbon did not stimulate denitrification in aquifer microcosms in the laboratory, suggesting that this was not an important carbon source for denitrification in our sites. Determining which carbon source is fueling denitrification has practical implications. Where buried horizons are the key source, surface management of the riparian zone will likely have little direct influence on groundwater denitrification. Where roots are the key source, changes in the plant community are likely to

  18. Organic carbon concentrations and stocks in Romanian mineral forest soils

    Directory of Open Access Journals (Sweden)

    Lucian C. Dincă

    2012-12-01

    Full Text Available Estimating soils organic carbon stock and its change in time is an actual concern for scientists and climate change policy makers. The present article firstly focus on determination of C stocks in Romania on forest soil types, as well as development of the spatial distribution mapping using a Geographic Information System (GIS and also the secondly on the quantification of uncertainty associated with currently available data on C concentration on forest soils geometrical layers. Determination of C stock was done based on forest management plans database created over 2000-2006. Unlike original database, the data for this study was harmonized on following depths: 0-10 cm, 10-20 cm, 20-40 cm, and > 40 cm. Then, the obtained values were grouped by soil types, resulting average values for the main forest