Effects Of Acid Rain On Forest Processes

A detailed analysis of acidification effects on forest soil, rhizosphere and plant life and on the processes connecting them such as nutrient uptake and mineral cycling. Presents findings from the Solling project, an important long-term study on acid rain results in Germany's Black Forest, as well as other European forests which have experienced severe acid rain damage as a means of evaluating and predicting similar harm to U.S. forests.

This volume contains papers presented at a NATO Advanced Research Institute, sponsored by their Eco-Sciences Panel, on "The effects of acid precipitation on vegetation and soils," held at Toronto, Canada from May 22-26, 1978. The organizing expenses and greater part of the expenses of the speakers and chair~en were provided by N.A.T.O. The scientific programme was planned by T. C. Hutchinson together with an international planning committee of G. Abrahamsen (Norway), G. Likens (U.S.A.), F.E. Last (U.K.), C.O. Tamm (Sweden) and B. Ulrich (W. Germany). Many of the dimensions of the 'acid rain' problem are common to countries of northern Europe and North America. The developing awareness over the past ten years of the international nature of the acid rain phenomenon has lead to studies documenting damaging effects on susceptible freshwater bodies. Large areas of the Canadian Pre-Cambrian Shield, with its extension into the United States, and the granitic areas of southern Norwayand Sweden contain lakes which are in the process of acidification. The biological resources of these affected areas are of considerable national concern. However, while clearly damaging effects of acidification on freshwater systems have been well documented, the impact of acid precipitation on terrestrial systems has not been so well understood.

This book traces centuries of human use and abuse of forest ecosystems by discussing past decades of intense burning, grazing, and timber cutting that added to the natural acidification of the soil. Air pollutants and acids generated by industrial activities worldwide are also considered. Many forests in Europe and North America now receive as much as 30 times more acidity than they would if rain or snow were falling through a pristine atmosphere; ozone levels in many rural areas of Europe and North America are now regularly in the range known to damage trees. The book is organized into six sections, an introduction and bibliography of cited references. Major topic areas discussed include: (1) signs of forest destruction worldwide; (2) pathways of pollution that in most cases are traced back to sulfur and nitrogen oxides emitted during the burning of fossil fuels; (3) economic and ecological reality of forest destruction; (4) controlling emissions through requirements for effective technology; (5) international cooperation as an essential factor in controlling a wholesale continental pollution trade; and (6) the emerging realization of the potential economic and ecological consequences of acid rain and air pollution. (BC)

There is no shortage of general books on the subject of acid rain, or of symposium proceedings reviewing work ranging from atmospheric chemistry and deposition processes to freshwater acidification and effects on vegetation. In contrast, the collection of papers from this Workshop is focussed on a much smaller subject, the processes of acid deposition at high altitude sites. Interest in deposition at high elevation sites comes largely from observed vertical gradients in the degree of forest damage at sites in the Federal Republic of Germany and the eastern United States. These gradients show that damage to Norway spruce and fir increases with altitude at sites in Bavaria and the Black Forest, and that Red spruce are declining at high elevation sites in the Appalachian Mountains. With the large scale of scientific interest in forest decline, cany research groups, during the last five years, have been examining atmospheric chemistry, deposition processes, and effects on vegetation and soils at upland sites. In particular there have been many recent studies of cloud and precipitation chemistry, which show much larger concentrations of all ions in cloud water than in rain or snow. These studies have also shown that processes of wet and dry deposition and also the chemistry of the air at hill tops are modified strongly by orographic effects.

A unique contribution to the literature on acidic deposition, this volume offers a collection of in-depth analysis of the key mechanisms governing forest response to acidic inputs. Among the mechanisms reviewed here are foliage leaching, aluminum mobilization, mineral weathering, soil organisms, and rhizosphere processes. Researchers and students in soil science, forest ecology, and environmental science, as well as policy makers and forest managers concerned with assessment of acidic deposition effects will value this concise monograph for its detailed examination of selected technical issues and its comprehensive reference sections.

The objective of this book is to outline the serious dangers to the soil and forest as a result of continuing emissions of acid-producing gases, thus pointing to the urgent need of their reduction. This volume reviews relevant information dealing with changes due to acidification of the soil and with the physiological processes of the tree involved in nutrient uptake, transfer, and utilization as well as with the nature and degree of damage that has occurred. Written in a comprehensive format, it discusses the importance of viable forests, the vital role of nutrients in the structure and physiology of the tree, and the relevance of prior dieback episodes. This is a valuable resource for those interested in forestry, environmental science, and the pulp and paper industry.