On the research program forest decline at the site 'Postturm', forest district Farchau/Ratzeburg

The Federal Ministry of Research and Technology, Bonn, supports since 1985 an interdisciplinary research project on forest decline at the forest district Farchau/Ratzeburg in northern Germany. There is a damaged old growth of mainly spruce (Picea abies (L.) Karst.) located at 60-80 m NN and 30 km apart of Hamburg. There are field stations for continuous measurement of concentrations and depositions of anorganic air pollutants and determination of organic compounds. Biological experiments are carried out to examine the interrelation between air pollutants and tree response. The stress exserted on fine roots via the soil is also considered. In addition, growth and wood characteristics are investigated, and genetic aspects are studied within this program. So far it turned out that above all short periods of exposure to gaseous pollutants may cause stress reactions of the trees. Dry depositions, particularly lead, are considerably high. An insufficient availability of divalent mineral nutrients parallel to an increased Al-antagonism in the mineral soil and a high lead content in the humus layer may seriously contribute to the stress shown by the spruce trees at that site. The program will be continued for several years. (orig.)