Occurrence of Gaseous Pollutants in Forest Stands

Abstract

As a contribution to the investigation of the causes of the forest-damage measurements of air pollution are carried out in the forest area “Schönbuch” 30 km south of Stuttgart and in the Black Forest near Freudenstadt. At the Schönbuch site the influence of the metropolitan area of Stuttgart can be clearly concluded from the nitrogen oxide immissions observed. In the Black Forest, mountain-valley-systems may lead to the accumulation of gaseous pollutants resulting in relatively high concentrations. There the influences of atmospheric barrier layers are of special significance. In the winter during east and northeast wind episodes long range transport of SO₂ is registered. Measurements of the concentration differences between above the canopy and in the forest stand provide information about the pollutant uptake by the trees. E.g. the concentration differences depend on the reactivity and the water solubility of the gases.