Five years of research carried out by the U.S. Department of Agriculture Forest Services' Northern Global Change Program, contributing to our understanding of the effects of multiples stresses on forest ecosystems over multiple spatial and temporal scales. At the physiological level, reports explore changes in growth and biomass, species composition, and wildlife habitat; at the landscape scale, the abundance distribution, and dynamics of species, populations, and communities are addressed. Chapters include studies of nutrient depletion, climate and atmospheric deposition, carbon and nitrogen cycling, insect and disease outbreaks, biotic feedbacks with the atmosphere, interacting effects of multiple stresses, and modeling the regional effects of global change. The book provides sound ecological information for policymakers and land-use planners as well as for researchers in ecology, forestry, atmospheric science, soil science and biogeochemistry.

The chapters in this book present a snapshot of the state of knowledge of air pollution effects at the beginning of the 21st century. From their different disciplines, a distinguished collection of authors document their understanding of how leaves, trees, and forests respond to air pollutants and climate change. Scenarios of global change and air pollution are described. The authors describe responses of forests to climate variability, tropospheric ozone, rising atmospheric CO2, the combination of CO2 and ozone, and deposition of acidic compounds and heavy metals. The responses to ozone receive particular attention because of increasing concern about its damaging effects and increasing concentrations in rural areas. Scaling issues are addressed - from leaves to trees, from juvenile trees to mature trees, from short-term responses to long-term responses, and from small-scale experiments and observations to large-scale forest ecosystems. This book is one major product of a conference sponsored by the International Union of Forestry Research Organizations, the USDA Forest Service Global Change Northern Stations Program, the Arthur Ross Foundation, NCASI, the Canadian Forest Service, and Michigan Technological University. The conference, held in May 2000 in Houghton, Michigan, USA, was appropriately titled "Air Pollution, Global Change, and Forests in the New Millennium". The Editors, David Karnosky, Kevin Percy, Art Chappelka, Caroline Simpson, and Janet Pikkarainen organized the conference and edited this book.

This volume offers a scientific assessment of the effects of climatic variability and change on forest resources in the United States. Derived from a report that provides technical input to the 2013 U.S. Global Change Research Program National Climate Assessment, the book serves as a framework for managing U.S. forest resources in the context of climate change. The authors focus on topics having the greatest potential to alter the structure and function of forest ecosystems, and therefore ecosystem services, by the end of the 21st century. Part I provides an environmental context for assessing the effects of climate change on forest resources, summarizing changes in environmental stressors, followed by state-of-science projections for future climatic conditions relevant to forest ecosystems. Part II offers a wide-ranging assessment of vulnerability of forest ecosystems and ecosystem services to climate change. The authors anticipate that altered disturbance regimes and stressors will have the biggest effects on forest ecosystems, causing long-term changes in forest conditions. Part III outlines responses to climate change, summarizing current status and trends in forest carbon, effects of carbon management, and carbon mitigation strategies. Adaptation strategies and a proposed framework for risk assessment, including case studies, provide a structured approach for projecting and responding to future changes in resource conditions and ecosystem services. Part IV describes how sustainable forest management, which guides activities on most public and private lands in the United States, can provide an overarching structure for mitigating and adapting to climate change.

Large-scale experimentation allows scientists to test the specific responses of ecosystems to changing environmental conditions. Researchers at Oak Ridge National Laboratory together with other Federal and University scientists conducted a large-scale climatic change experiment at the Walker Branch Watershed in Tennessee, a model upland hardwood forest in North America. This volume synthesizes mechanisms of forest ecosystem response to changing hydrologic budgets associated with climatic change drivers. The authors explain the implications of changes at both the plant and stand levels, and they extrapolate the data to ecosystem-level responses, such as changes in nutrient cycling, biodiversity and carbon sequestration. In analyzing data, they also discuss similarities and differences with other temperate deciduous forests. Source data for the experiment has been archived by the authors in the U.S. Department of Energy's Carbon Dioxide Information and Analysis Center (CDIAC) for future analysis and modeling by independent investigators.

Proceedings of the First European Symposium on Terrestrial Ecosystems: Forests and Woodland, held at Florence, Italy, 20-24 May 1991

Abstract: "This report documents trends and impacts of climate change on America's forests as required by the Renewable Resources Planning Act of 1974. Recent research on the impact of climate and elevated atmospheric carbon dioxide on plant productivity is synthesized. Modeling analyses explore the potential impact of climate changes on forests, wood products, and carbon in the United States."

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.

This book arises out of a symposium on forest and woodland terrestrial ecosystems which was held in Florence on 20-24th May 1991. It was organised jointly by the Commission of the European Communities (CEC) and the European Science Foundation (ESF) in association with the Italian Research Council (CNR). The symposium brQughUogether most -Of the internationally recognized groups working on forest ecosystems including biologists, botanists, ecologists, soil scientists, modellers, foresters and policy makers. All the CEC countries were represented. In addition, there was a broad audience from Eastern and Central Europe and from EFfA countries. Outstanding experts from outside Europe (US, Australia, Canada, Japan, China, etc.) were also present. In total, the symposium was attended by more than 500 participants. The structure of this book reflects the main elements of the meeting. As such it includes three main sections. The first consists of six major state-of-the-art reviews corresponding to the six plenary sessions, each followed by a discussion which has been summarized by rapporteurs. The reviews were prepared to assess critically the state of current knowledge in ecosystem research and to provide a scientific basis both for policy decisions and for further research.