Ozonbelastung von Waldbäumen in der Schweiz und damit verbundene Wachstumseinbussen

Ozone impact on forest trees in Switzerland and resulting growth reductions Ozone (O3) is highly phytotoxic. Basing on dose-effect relationships resulting from fumigation experiments, the United Nations Economic Commission for Europe (UNECE) has set critical levels for protection of the vegetation. The present article compares the AOT40 (accumulated ozone over a threshold of 40 ppb) summing up hourly ozone concentrations with a flux-based risk assessment taking into account stomatal ozone uptake. Both ozone quantifications were calculated for rural monitoring stations in Switzerland, mapped and compared to the corresponding critical levels. The data suggest that the ozone load in Switzerland is high enough to provoke clear reductions in forest growth.