Land Use and Carbon Sequestration in Eastern Deciduous Forests: Complex Interactions Between Human Activities and Ecosystem Processes

点击翻译按钮获取中文摘要

ABSTRACTObserved warming at the Earth's surface has raised concerns about the effects of increased carbon dioxide in the global environment, and understanding the role of forests as potential carbon sinks is becoming a national and global priority. The objective of this project is to investigate the role of recent past, current, and future land use change on carbon dynamics in eastern deciduous forests of North America. Eastern deciduous forests may have played a major role in past carbon dioxide uptake due to regrowth following major cutting at the turn of the century. Current rates of timber harvest in eastern deciduous forests are high, so future land use and cover changes may again affect carbon cycling. These forests are managed under a diverse set of public and private management regimes, with each group possessing different motivations for land management and potentially responding differently to economic incentives. The project's research questions address the interactions between human activities (forest management) and an ecosystem process (carbon sequestration) in temperate deciduous forests of West Virginia: 1) How do carbon stocks differ between forests with different land use practices? 2) How have changes in land management (1989-2000) affected carbon stocks, and what were the human drivers of this land use change? 3) How might the ability of central hardwood forests to store carbon change under future conditions? To address these research questions, an ecosystem model (Pnet-CN) will be calibrated and validated at two spatial scales (watershed and state). At the watershed level, PnET-CN will be calibrated for four management treatments: mature forest, young forest, and two types of diameter limit cuts. At the state level, PnET-CN will be run for 1989 and 2000 at USDA Forest Service, Forest Inventory and Analysis (FIA) plot locations classified by management strategy to match those of the experimental watersheds. This model of productivity will be linked to an econometric model that investigates correlations between land-use/land-management categories and their potential drivers, using FIA plot data combined with information on plot accessibility, management regime, and local hardwood timber prices. The econometric model will be coupled with the ecosystem model to conduct scenario analysis linking changes in drivers of land use and cover change to changes in carbon storage. Scenarios holding drivers of land use and cover change fixed, but varying climate parameters, will also be developed. Understanding the human causes of land use and cover change and their consequences for the carbon cycle is critical given elevated levels of carbon dioxide in the atmosphere. This research addresses the important interaction between drivers of land use change, terrestrial ecosystems, and carbon balance by directly linking economic causes of timber harvest to details of forest biomass and productivity. Results from this project will help state and national agencies manage temperate deciduous forests in the context of future economic and climatic changes. This research will also enhance scientific understanding of the role of deciduous forests in the carbon cycle through broad dissemination of results in scientific journals and conferences, through the support of graduate research assistants, undergraduate field assistants, and through the development of graduate and undergraduate teaching modules.