Effect of Air Pollution on Forest Growth in Southwestern Germany - Hunting for a Phantom? -

1990

S. 388-395

4 Abb., 12 Lit. Ang.

Unselbständiges Werk

200085929

Air pollution effects on forest ecosystems depend on types of pollution, site conditions and sensitivity of trees and stands. The question is: Have tree growth rates been influenced? First results of growth analysis on trees with different needle losses suffered widely from problems with methods and interpretation of measurement results. Differences in growth rates due to stand dynamics were misunderstood as "forest damages". There is evidence for widely better growth in Southwest-Germany and the adjoining regions of France and Switzerland, which means improved site conditions. The reasons were assumed in a combination of atmospheric depositions, especially nitrogen mineralisation due to climate and silviculture, CO2-increase in the atmosphere and more favourable climatic conditions for decades. Today we become aware of the methodic problems when testing growth and its correlation with forest damages. A reliable interpretation of dendrometric data seems possible if longer lasting measurement series of characteristics of the ecosystem's performance will be available.