Download or read book Modeling the Carbon and Nitrogen Dynamics Following Disturbance in Eastern U S Forests written by Shree Ram Sharma Dangal and published by . This book was released on 2011 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: Key words: Disturbance, Net Ecosystem Productivity (NEP), Biometric NEP, Eddy Co-variance.

Download or read book Carbon and Nitrogen Dynamics of Northeastern U S Forests in Response to Environmental Stress written by Scott V. Ollinger and published by . This book was released on 2000 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The Impact of Disturbance on Carbon Stores and Dynamics in Forests of Coastal Alaska written by Mikhail A. Yatskov and published by . This book was released on 2016 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: Changes in climate caused by increased concentrations of carbon dioxide (CO2) in the Earth’s atmosphere have led land and ocean surface temperatures to increase by 0.85°C and sea level to increase by 19 cm relative to preindustrial times. Global climate change will lead to further alterations in mean temperature and precipitation, as well as their extremes that are likely to influence disturbance regimes. Disturbance play an important role in forest dynamics and succession, by influencing forest ecosystems structure and function, reorganizing forests by reducing live and increasing dead matter, and thus affecting ecosystem carbon (C) balances. Under a changing climate disturbances are likely to cause widespread tree mortality across forested landscapes, creating vast amounts of coarse woody debris (CWD) that will emit C to the atmosphere to a degree that regional C balances and future C dynamics are likely to change. C balance of forested regions depends on inputs in form of C sequestered by live components during growth and outputs in form of C emitted from dead components through decomposition and combustion. Live trees in many forest ecosystems represent the largest aboveground C pool and the dynamics of this pool, as controlled by growth and mortality, have been extensively studied. In contrast, few have examined either the post-disturbance fate of CWD C or assessed C storage potential of salvaged biomass despite the occurrence of multiple recent large-scale disturbance events. Biomass and C stores and their uncertainty were estimated in the Temperate and the Boreal ecoregions of Coastal Alaska using the empirical data from the Forest Inventory and Analysis (FIA) program, literature data, and modeling using standard methods employed by the FIA program. The average aboveground woody live (218.9±4.6 Mg/ha) and log (28.1±1.8 Mg/ha) biomass in the Temperate ecoregion were among the lowest in the Pacific Northwest, whereas snag biomass (30.5±1.0 Mg/ha) was among the highest. In the Boreal ecoregion, CWD biomass comprised almost 50% of the regional aboveground woody store (76.7±3.8 Mg/ha) with bark beetle damaged stands containing 82% of the total CWD biomass. In contrast, in the Temperate ecoregion, CWD comprised 20% of the regional aboveground woody store (277.5 ±5.4 Mg/ha) with 76% of total CWD biomass in undisturbed stands. Total C stores estimates in Coastal Alaska ranged between 1523.6 and 1892.8 Tg with the highest contribution from soils and the largest potential reductions in uncertainty related to the tree and soils C pools. The impact of a large-scale spruce bark beetle (SBB) outbreak on aboveground dead wood C dynamics on the Kenai Peninsula was modeled utilizing data from the FIA program and CWD decomposition rate-constants from a chronosequence and decomposition-vectors analysis. Decomposition rate-constants from the chronosequence ranged between -0.015 yr−1 and -0.022 yr−1 for logs and -0.003 yr−1 and +0.002 yr−1 for snags. Decomposition rate-constants from the decomposition-vectors ranged between -0.045 yr−1 and +0.003 yr−1 among decomposition phases and -0.048 yr−1 and +0.006 yr−1 among decay classes. Relative to log generating disturbances those creating snags delayed C flux from CWD to the atmosphere, produced a smaller magnitude C flux, and had the potential to store 10% to 66% more C in a disturbed system over time. The effect of several management strategies ranging from "leave-as-is" to "salvage-and-utilization" on C stores and emissions following SBB outbreak on Kenai Peninsula, Alaska was evaluated. A forest with immediate post-disturbance regeneration reached pre-disturbance C stores faster than one with delayed regeneration. Lack of regeneration, representing a loss of tree cover on the disturbed portion of the landscape, caused a permanent decrease in wood C stores. Among the "salvage-and-utilization" scenarios considered, biomass fuel production with substitution for fossil fuels created the largest long-term C storage assuming the substitution was permanent. Given that reduction in near-term emissions may be a more robust strategy than long-term ones, the "leave-as-is" scenarios may represent the most feasible way to mitigate global climate change following disturbance.

Download or read book Carbon and Nitrogen in Forest Ecosystems Series I written by Yowhan Son and published by MDPI. This book was released on 2021-01-20 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding the differences in carbon and nitrogen distribution and cycling both spatially and temporally using various approaches is essential in forest ecosystems. In addition, the influence of biotic and abiotic factors as well as natural and artificial disturbances on carbon and nitrogen cycling need to first be understood before drawing their implications to forest management practices. This Special Issue aims to understand carbon and nitrogen distribution and cycling in forest ecosystems for ecosystem-based forest management under different natural and artificial disturbances.

Download or read book Effects of Drought on Forests and Rangelands in the United States written by James M. Vose and published by . This book was released on 2016 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences for forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed; however, even moderate drought can have long-lasting impacts on the structure and function of forests and rangelands without these obvious large-scale changes. Large, stand-level impacts of drought are already underway in the West, but all U.S. forests are vulnerable to drought. Drought-associated forest disturbances are expected to increase with climatic change. Management actions can either mitigate or exacerbate the effects of drought. A first principal for increasing resilience and adaptation is to avoid management actions that exacerbate the effects of current or future drought. Options to mitigate drought include altering structural or functional components of vegetation, minimizing drought-mediated disturbance such as wildfire or insect outbreaks, and managing for reliable flow of water.

Download or read book Advancing Toward Closed Forest Ecosystem Models written by Merrill R. Kaufmann and published by . This book was released on 1990 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Changes in Carbon Dynamics Following Wildfire in Soils of Interior Alaska written by Katherine P. O'Neill and published by . This book was released on 2000 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Boreal forests contain large amounts of soil carbon and are susceptible to periodic wildfires. Predicting the response of soil carbon dynamics to fire disturbance requires understanding: (1) the environmental factors governing CO2 efflux; (2) the extent to which fire alters these factors; and, (3) the length of time over which these perturbations persist. In interior Alaska seasonal patterns of CO2 efflux, soil temperature. and soil moisture potential were measured in burned and control pairs of aspen, white spruce, and black spruce stands. Averaged over the growing season, mean CO2 efflux from burned stands (0.51 ± 0.26 g CO2 m−2 hr−1) was two-thirds that of control stands (0.77 ± 0.44 g CO2 M−2 hr1). Soil temperature explained 85 to 90% of the seasonal variability in the control, whereas moisture was a more important determinant in burned stands. Laboratory incubations of recently burned and control humic material indicate that changes in substrate chemistry and increased temperature may enhance rates of decomposition by a factor of 2.2 to 2.8 in the first decade after fire, resulting in a release of 6.3 to 13.4 Mg C ha−1 to the atmosphere. Under saturated moisture conditions, respiration from mosses may contribute 16 to 50% of total soil CO2 emissions. In a 140-year age-sequence of burned black spruce stands, CO2 efflux increased at an average rate of 8.3 kg C ha−1 yr1 up to a maximum of 1.83 Mg C ha−1 yr1. During this same time, accumulation of carbon in organic horizons ranges from 0.34 to 0.50 Mg C ha−1 yr1 and the ratio of microbial to root respiration decreased from 76:24 to 13:87. Numerical modeling of carbon accumulation suggests that these soils functioned as a net source of carbon for the first 7 to 15 years after fire and released 1.8 to 11.0 Mg C ha−1 to the atmosphere. Although conservative, these estimates of post-fire biogenic emissions are on the same order of magnitude as carbon losses during combustion itself, suggesting that current models may underestimate the impact of fire in northern latitudes by as much as a factor of two"--Leaves iv-v.

Download or read book Modeling the Nitrogen Dynamics of Sludge amended Forests written by David Michael Crohn and published by . This book was released on 1992 with total page 570 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Productivity of America s Forests and Climate Change written by and published by . This book was released on 1995 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The North American Carbon Budget and Implications for the Global Carbon Cycle written by and published by . This book was released on 2007 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accompanying CD-ROM contains full text of book and appendixes. Cf. menu frames of CD-ROM.

Download or read book Assessment of the Influence of Disturbance Management Activities and Environmental Factors on Carbon Stocks of U S National Forests written by and published by . This book was released on 2019 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report assesses how carbon stocks at regional scales and in individual national forests are affected by factors such as timber harvesting, natural disturbances, climate variability, increasing atmospheric carbon dioxide concentrations, and nitrogen deposition. Previous baseline assessments of carbon stocks (https://www.fs.fed.us/managing-land/sc/carbon) evaluated observed trends based on forest inventory data but were limited in ability to reveal detailed causes of these trends. The expanded assessments reported here are based on an extensive disturbance and climate history for each national forest, and two forest carbon models, to estimate the relative impacts of disturbance (e.g., fires, harvests, insect outbreaks, disease) and nondisturbance factors (climate, carbon dioxide concentration, nitrogen deposition). Results are summarized for each region of the National Forest System in the main document. A set of regional appendices to this report provides more detailed information about individual national forests within each region. Results are highly variable across the United States. Generally, carbon stocks are increasing in forests of the eastern United States as these forests continue to recover and grow older after higher historical harvesting rates and periods of nonforest land use. In contrast, carbon stocks in forests of the western United States may be either increasing or decreasing, depending on recent effects of natural disturbances and climate change. The information supports national forest units in assessing carbon stocks, quantifying carbon outcomes of broad forest management strategies and planning, and meeting carbon assessment requirements of the 2012 Planning Rule and directives. Results of these expanded assessments will provide context for project-level decisions, separated from the effects of factors that are beyond land managers' control.

Download or read book Spatial Modeling of Carbon Sequestraton by Forest Ecosystems in the Hudson River Valley New York written by Mary Elizabeth Killilea and published by . This book was released on 2005 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Assessment of the Influence of Disturbance Management Activities and Environmental Factors on Carbon Stocks of United States National Forests written by Richard A. Birdsey and published by . This book was released on 2019 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Model of Carbon and Nitrogen Dynamics for Temparate Grasslands and Forests written by Enrique Gomezdelcampo and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades, the importance of hydrological processes for ecosystem dynamics and the effects of plants on hydrological processes has become increasingly apparent. A better understanding of the relationship between plant growth (carbon and nitrogen distribution) and the hydrological characteristics of a catchment would improve ecological assessments and management of forests and grasslands. TOPDNDC, developed for this study, is a detailed, semi-distributed, quantitative, ecohydrological model for predicting carbon and nitrogen dynamics in small temperate catchments. TOPDNDC establishes an explicit linkage between the biogeochemical process and the hydrology of catchments using the well-known and tested biogeochemical model DNDC and hydrological model TOPMODEL. The new model's ability to predict is assessed against field data. The TOPDNDC computer model does not require use of high performance computers or large and expensive datasets, but it allows investigation in detail of how the locations and spatial patterns of biogeochemical processes shift across watershed topography in response to antecedent conditions and multiple temporal scales. Application of the model to annual biomass production from a grassland shows very good agreement with the field data. The temperate forest simulation showed lesser agreement with field data collected along a transect in a watershed, but was able to reproduce the same patterns found in the field and with high correlations. The difference in the results between the grassland and forest simulations may result, in part, from the intentionally simple link between the lateral and vertical water distribution components of the model.

Download or read book Analysis of the Regional Carbon Balance of Pacific Northwest Forests Under Changing Climate Disturbance and Management for Bioenergy written by Tara W. Hudiburg and published by . This book was released on 2012 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric carbon dioxide levels have been steadily increasing from anthropogenic energy production, development and use. Carbon cycling in the terrestrial biosphere, particularly forest ecosystems, has an important role in regulating atmospheric concentrations of carbon dioxide. US West coast forest management policies are being developed to implement forest bioenergy production while reducing risk of catastrophic wildfire. Modeling and understanding the response of terrestrial ecosystems to changing environmental conditions associated with energy production and use are primary goals of global change science. Coupled carbon-nitrogen ecosystem process models identify and predict important factors that govern long term changes in terrestrial carbon stores or net ecosystem production (NEP). By quantifying and reducing uncertainty in model estimates using existing datasets, this research provides a solid scientific foundation for evaluating carbon dynamics under conditions of future climate change and land management practices at local and regional scales. Through the combined use of field observations, remote sensing data products, and the NCAR CESM/CLM4-CN coupled carbon-climate model, the objectives of this project were to 1) determine the interactive effects of changing environmental factors (i.e. increased CO2, nitrogen deposition, warming) on net carbon uptake in temperate forest ecosystems and 2) predict the net carbon emissions of West Coast forests under future climate scenarios and implementation of bioenergy programs. West Coast forests were found to be a current strong carbon sink after accounting for removals from harvest and fire. Net biome production (NBP) was 26 ± 3 Tg C yr−1, an amount equal to 18% of Washington, Oregon, and California fossil fuel emissions combined. Modeling of future conditions showed increased net primary production (NPP) because of climate and CO2 fertilization, but was eventually limited by nitrogen availability, while heterotrophic respiration (R[subscript h]) continued to increase, leading to little change in net ecosystem production (NEP). After accounting for harvest removals, management strategies which increased harvest compared to business-as-usual (BAU) resulted in decreased NBP. Increased harvest activity for bioenergy did not reduce short- or long-term emissions to the atmosphere regardless of the treatment intensity or product use. By the end of the 21st century, the carbon accumulated in forest regrowth and wood product sinks combined with avoided emissions from fossil fuels and fire were insufficient to offset the carbon lost from harvest removals, decomposition of wood products, associated harvest/transport/manufacturing emissions, and bioenergy combustion emissions. The only scenario that reduced carbon emissions compared to BAU over the 90 year period was a 'No Harvest' scenario where NBP was significantly higher than BAU for most of the simulation period. Current and future changes to baseline conditions that weaken the forest carbon sink may result in no change to emissions in some forest types.

Download or read book Forest Ecosystems written by David A. Perry and published by JHU Press. This book was released on 2008-07-24 with total page 631 pages. Available in PDF, EPUB and Kindle. Book excerpt: 2009 Outstanding Academic Title, Choice This acclaimed textbook is the most comprehensive available in the field of forest ecology. Designed for advanced students of forest science, ecology, and environmental studies, it is also an essential reference for forest ecologists, foresters, and land managers. The authors provide an inclusive survey of boreal, temperate, and tropical forests with an emphasis on ecological concepts across scales that range from global to landscape to microscopic. Situating forests in the context of larger landscapes, they reveal the complex patterns and processes observed in tree-dominated habitats. The updated and expanded second edition covers • Conservation • Ecosystem services • Climate change • Vegetation classification • Disturbance • Species interactions • Self-thinning • Genetics • Soil influences • Productivity • Biogeochemical cycling • Mineralization • Effects of herbivory • Ecosystem stability

Download or read book Effects of Climate Change on Agriculture Land Resources Water Resources and Biodiversity in the United States written by Peter Backlund and published by DIANE Publishing. This book was released on 2009-05 with total page 250 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report by the Nat. Science and Tech. Council¿s U.S. Climate Change Science Program (CCSP) is part of a series of 21 reports aimed at providing current assessments of climate change science to inform public debate, policy, and operational decisions. These reports are also intended to help the CCSP develop future program research priorities. The CCSP¿s guiding vision is to provide the Nation and the global community with the science-based knowledge needed to manage the risks and capture the opportunities associated with climate and related environmental changes. This report assesses the effects of climate change on U.S. land resources, water resources, agriculture, and biodiversity. It was developed with broad scientific input. Illus.