Diagnosis of damage in forest trees by integrated biochemical parameters

Abstract

Bioindication can be carried out at different levels, ranging from cell metabolism up to the whole ecosystem. The annual forest damage surveys in several European states are based on bioindication procedures that chiefly use the visual parameters like foliage loss and yellowing. While the visible monitoring of damage is related to the level of the organism as a whole, some biochemical parameters may serve as damage indicators on the level of cell metabolism These indicators may be components of the photosynthetic apparatus, antioxidants, phytohormons, phenolic compounds and parameters that relate to water status. Because of their difference in spatial and temporal dimensions these two methods of bioindication complement each other to a complete picture of the state of vitality of forest trees. Because of their non-uniform assignation to different metabolic processes, an integration of the individual biochemical indicators is necessary. Therefore an index, the biochemical damage index (BDI), was calculated from the estimated threshold values deduced from comparative data from well-known sites and experiments under controlled conditions. In the present study visible damage symptoms and the BDI as an integrated biochemical indicator of tree vitality from six variously damaged trees from each of ten Norway spruce permanent-observation sites located in SW-Germany were compared with six trees from an undamaged reference site during a time-span of three years. Our results confirm that biochemical indication is a reliable tool for diagnosis of damage of forest trees.