1 Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf, Switzerland
Environmental changes induced by mankind are numerous in nature and in effects. Changes affecting the hydrosphere and the atmosphere are spread geographically by water and air circulation, with the potential of creating not only local but also regional and global problems. Ecosystems far from pollution sources are thus also affected, which is the case of many forests. The biggest concern at the beginning of this twenty-first century is certainly the global climatic change driven by human activities. This change includes not only physical components like temperature and precipitation, but also chemical components like air quality and deposition of pollutants.