Forest decline became a matter of public and scientific concern in France in 1983 when conifers in the Vosges mountains were found to exhibit unusual crown deterioration. An impassioned controversy on a supposedly large scale forest health problem was then in full swing in Central Europe. A co-ordinated research programme entitled DEFORPA ("Deperissement des For~ts et Pollution AtmospMrique") was launched in 1984. This programme ran from 1984 to 1991 and a number of projects are still in progress. The Programme was sponsored by three French ministries (Enviroument, Agriculture and Forestry, Research and Technologyl), several state agencies, various regional authorities and the Commission of the European Communities (DO xn and DG VI). Initially, emphasis was solely laid on the understanding of forest decline in the mountainous areas - because damage was most obvious there - in relation to natural and man-made factors. Air pollution was given high but not overwhelming priority. Thus, the DEFORPA Programme was not in its essence a nation-wide assessment of air pollution effects, unlike a number of national acidification research programmes in Europe and North America. During. the programme, however, the areas of concern expanded. In particular, research into water acidification in the Vosges mountains was developed in parallel with the DEFORPA Programme, and possible eutrophication of the ground flora in northeastern France became the subject of new research.

R. F. HUTTL AND W. SCHAAF Brandenburg Technical University Cottbus, Chair of Soil Protection and Recultivation, P.O. Box 10 13 44, 03013 Cottbus, Germany The health status of forest trees and stands is determined by numerous site factors such as chemical, physical, and biological soil factors, water supply, climate, weather conditions, management history as well as atmospheric deposition impacts. In this context, the nutrient supply is an important evaluation parameter. Forest trees well supplied with nutrients are more resistant to stresses that affect the forest ecosystem than other trees. This is true for both biotic and abiotic influences. Therefore the investigation of the so-called 'new type forest damage' was aimed at the exact determination of the health status of damaged trees. When considering the complete forest ecosystem, health (=vitality) means the sustainable ability to withstand negative environmental influences and still remain stable and productive. From this viewpoint, an optimal nutritional status is a prerequisite for an optimal health status. The term 'new type forest damage' comprises a number of damage symptoms which have been observed in various tree species on very different sites since the mid-1970s, particularly in Europe and North America. However, they occurred much more intensively in the 1980s. Generally, this forest damage was thought to be related to negative impacts of air pollutants.

This book looks at the sources and composition of the atmosphere and rainfall, with particular attention on acidifying components and those that affect ecosystems. It further widens the subject to look at trace metals. It includes papers on the impact of deposition on soils and forests and the recovery of the natural environment. Work on critical loads makes a contribution to understanding the degree to which deposition must be reduced to limit its impact.

Accompanying CD-ROM "provides a complete database of all flux, storage and species observations for modellers."--Page 4 of cover.

This Special Issue of Water, Air and Soil Pollution offers original contributions from BIOGEOMON, an international symposium on ecosystem behavior and the evaluation of integrated monitoring of small catchments, held in Prague, Czech Republic, in September 1993. The meeting attracted nearly 200 scientists from 27 countries on five continents. BIOGEOMON was a loose continuation of another international meeting, GEOMON, which was held in Prague in 1987. Both sym posia provided a forum for the discussion of ideas on environmental problems in western and eastern Europe, with important contributions from the American continent. With the dramatic collapse of the iron curtain, it was our hope that more so than GEOMON, BIOGEOMON would provide opportunities for the free exchange of ideas, fostering the development of research collaborations between its participants. With international openness comes the increasing realization that every indus trialized nation has its own legacy of environmental degradation. Anthropogenic impacts differ in severity and scale; air and water transport of pollutants transform local impacts into regional and global ones, ignoring political boundaries and eco nomic differences. Environmental consequences of anthropogenic activities often are detectable at the ecosystem level. Thus, the challenge of ecosystem science, and to the individuals who practice it, is to develop a comprehensive understanding of ecosystem function in the past and at present, and to apply such understanding toward minimizing future insults to the local, regional, and global environment.

This volume contains a selection of scientific papers which were presented at an international workshop on the impacts of climatic variability held in Wengen, Switzerland, September 1997. For the first time, an assessment is made of the interactions between physical and biological elements of the Earth System on the basis of shifts in extreme climatic conditions, rather than simply changes in mean atmospheric conditions which research has tended to focus on until recently. Natural ecosystems and forests are typical examples of systems which, while constrained within certain ranges of mean climate, can undergo rapid and often irreversible damage in the face of short-lived but intense extreme events.

Used by humans since ancient times, evergreen oak forests still cover extensive mountain areas of the Mediterranean Basin. These broadleaved evergreen forests occupy a transitional zone between the cool-temperate deciduous forest biome and the drier Mediterranean pine forests and shrublands. Slow growing and casting a deep shade, the sclerophyllous holm oak (Quercus ilex) absolutely dominates the closed canopy of many Mediterranean evergreen oak forests. This is a synthesis of 20 years of research on the structure, function, and dynamics of holm oak forests in two intensively studied experimental areas in Spain. By combining observational measurements at the leaf, tree, plot, and catchment scales with field experiments and modelling, the authors explore how these forests cope with strong water limitation and repeated disturbances.