MODELING ASPECTS OF FOREST DECLINE IN GERMANY - I - THEORETICAL ASPECTS AND CAUSE-EFFECT RELATIONSHIPS

In 1993 the German Federal Environmental Agency initiated a project to evaluate the forest decline research of the period 1982-1992 in Germa ny. The development of the symptoms of the 'new type of forest decline ' is the effect of direct and indirect impacts on trees and ecosystems . The cause-effect relationships concerning the soil/plant interface a re discussed shortly. One aim of the project was the integration of qu antitative and qualitative research results in a simulation model. Acc ording to the manifold site conditions in Germany and possible combina tions of direct and indirect stress factors a flexible model structure with a modular construction was chosen. The modules can operate indiv idually or together. This enables the user to test hypotheses, or calc ulate scenarios. Thus, the model acts as a link between empiricism and theory. The practical and theoretical constraints and problem solutio ns are discussed. In a second paper the model performance and its appl icability range are shown [1, this volume]. (C) 1998 Elsevier Science Ltd.