Forest Succession and Climatic Change: Coupling Land-Surface Processes andEcological Dynamics

摘要

Growing evidence supports the hypothesis that humans are in the process ofinadvertently modifying the Earth's climate by increasing the atmospheric concentrations of carbon dioxide and other radiatively active trace gases. The present man-induced climatic change, often referred to as the 'greenhouse effect,' is different from natural changes because of its unprecedented pace and one's incomplete knowledge of its consequences. As some scientists put it, humanity is performing on itself a 'global experiment' which may entail a number of surprises. The potential changes in the behavior of atmosphere/biosphere interactions are of particular importance. Such changes could affect atmospheric dynamics, the local and regional hydrology, the global biogeochemistry, and, therefore, human societies. In the present thesis, five distinct aspects of climate/vegetation interactions are examined. The main part of the thesis focuses on the response of forests to climatic changes using a model treating the physics of energy and water exchange in detail. Because the Energy, water, and momentum eXchange, and Ecological dynamics model (EXE), couples the land-surface processes and the ecological dynamics of forests of northeast America, new insights are gained into the behavior of forests, in general, and the possible consequences of a greenhouse effect on forest hydrology and vegetation succession, in particular.