Das Projekt "Auswaschung phytotoxischer Verbindungen aus den Nadeln der Gemeinen Fichte und den Blaettern der europaeischen Buche im Verhaeltnis zum Fortschreiten der Krankheit des Waldes" wird vom Umweltbundesamt gefördert und von Technische Universität München, Forstwissenschaftliche Fakultät, Lehrstuhl für Forstbotanik durchgeführt. Objective: To check if the leaching of phytotoxic compounds from the canopy of trees affected by air pollution can affect the soil vegetation. General Information: It is not excluded that immissions may lead to production and accumulation of substances, which may affect the soil vegetation and the affected tree itself after their release from leaves of the diseased trees by leaching processes. This possibility is planned to be proved by the following experiments: 1. Isolating and analysing substances leached out of foliage of healthy and diseased trees. 2. Testing these substances in bioassays with several test species (triticum, nasturtium, picea). 3. Testing the activity of these substances on the plants constituting the soil vegetation, in vitro and in situ. 4. Testing the activity of these substances on seedlings of different tree species (in vitro and in situ). 5. Establishing field plots with several test species under and away from canopies of diseased and apparent healthy trees. 6. Testing the influence of ph on leaching intensity (in quantity and quality). 7. Laboratory tests with different soil substrates: Partly from under the crowns of health and of diseased trees.