Assessment of total nitrogen and proton deposition in selected ecosystems in Switzerland

Using the 'critical loads' approach, an attemp is made to estimate the concentrations of nitrogen and acid in the forest stands of the Swiss low mountain country; it is compared with the critical freights which were set by the UN ECE. The total freights are estimated from the sum of the freight of the outdoor precipitation and the products from measured concentrations and experimental deposition velocities. One finds that most ecosystems are endangered on a long-term basis, in particular through the nitrogen deposition of 27 to 71 kg (N)/ha year. The acid entry is probably less relevant than nitrogen on the basic rocks of the low mountain ranges. (orig.)