Robert A. Mickler - Böcker

This book summarizes a five-year research program on the impact of air pollution on southern commercial forests. Topics covered include: the condition of southern commercial forests, abiotic and biotic stress factors on southern pine forests, growth and physiological effects of regional air pollutants on southern pines, and impacts of atmospheric deposition and ozone on southern commercial pines. The book will be of interest to scientists working on the effects of air pollution on trees, as well as environmentalists, policymakers, and resource managers.

In the Global Change Research Act of 1990, "global change" is defined as "changes in the global environment (including alterations in climate, land productivity, oceans or other water resources, atmospheric chemistry, and ecological systems) that may alter the capacity of the Earth to sustain life. " For the purposes of this book, we interpret the definition of global change broadly to include physical and chemical environmental changes that are likely to affect the productivity and health of forest ecosystems over the long term. Important environmental changes in the Northern United States include steadily increasing atmospheric carbon dioxide, tropospheric ozone, wet and dry deposition of nitrogen and sulfur compounds, acidic precipitation and clouds, and climate variability. These environmental factors interact in complex ways to affect plant physiological functions and soil processes in the context of forest landscapes derived from centuries of intensive land use and natural disturbances. Research in the North has begun to unravel some key questions about how environmental changes will impact the productivity and health of forest ecosystems, species distributions and abundance, and associations of people and forests. Initial research sponsored by the USDA Forest Service under the United States Global Change Research Program (USGCRP) was focused on basic process-level understanding of tree species and forest v VI Preface ecosystem responses to environmental stress. Chemical pollution stresses received equal emphasis with climate change concerns.

The public's attitude toward air pollution in the United States evolved substantially during the 1960s. One of the results of the nation's emerging environmental ethic was the creation of the U. S. Environmental Protection Agency (EPA) in December of 1970. Prior to this time, research was focused on the impacts of air pollution on human health and welfare and was largely conducted by several federal research agencies, which included the Department of Health, Education, and Welfare; the National Oceanic and Atmospheric Administration; and the U. S. Department of Agricul­ ture. After the creation of the EPA, much of this work was consolidated in one regulatory agency, which resulted in periodic evaluations of the various effects of atmospheric pollution on human health, materials, agriculture, and forest ecosystems. At the same time that environmental interest was growing in the United States, concern increased in the European scientific community and public over the ecological impacts of acidic deposition. As the magnitude of the damage to European lakes and streams and the widespread decline in Norway spruce and silver fir was reported, concern that similar problems were occurring in the United States increased substantially. This concern was heightened by press reports of high elevation spruce-fir forest declines in the Adirondack and Appalachian Mountains and the decline and death of sugar maples in the northeastern United States and Canada.