General methods and materials

In the winter of 1982-83 an experiment was initiated at the University of Hohenheim to investigate the long-term effects of near ambient concentrations of O(3), SO(2), and simulated acidic rain and fog, alone and in combination, on mineral cycling, physiology, biochemistry and anatomy of Norway spruce (Picea abies L. Karst.), Silver fir (Abies alba Mill.) and European beech (Fagus silvatica L.) seedlings in model ecosystems. Open-top chambers above soil lysimeters were protected with shelters 1 m above the open-top against intrusion of ambient dust and rain. The soil, a replaced acid brown earth with a base saturation of 20-30% was from the Black Forest region of the Federal Republic of Germany. This paper describes the technical design aspects of the study, including chamber construction and ventilation, SO(2) and O(3) application and monitoring, simulated precipitation forms and dispensing features, and the environmental parameters monitored. A short description of the plants used and the soil status is also presented. Chamber climatic and edaphic conditions allowed tree seedling normal growth over the five years of study. The pollutant levels within the appropriate chambers were comparable to ambient concentrations found at southwest German forest sites and varied with weather conditions.