The "Zöbelboden" in the Reichraminger Hintergebirge is a centerpiece of long-term ecological research in Europe. The mountain forest habitat on carbonate rock is particularly sensitive to climate change and air pollution. Many pollutants are transported over long distances, but some of the pollution is also "home-made". Since 1992, the Federal Environment Agency has been investigating the influence of pollutants in forests at Zöbelboden. The results of the measurements show the air quality at Kalkalpen National Park, the effectiveness of international clean air agreements and the effects of climate change on mountain forests.