In 1984, our institute started to establish permanent forest observation plots on behalf of the Swiss cantons Aargau, Bern, Basel-City, Basel Country, Solothurn, Zug and Zurich. Thurgau joined the programme in 2007, Graubünden as well as a consortium of the central Swiss cantons Luzern, Nidwalden, Obwalden, Schwyz and Uri joined in 2015. In behalf of the Swiss Federal Office for the Environment, the forest observation programme is supplemented by specific case studies and field experiments.
Permanent forest observation involves the investigation of tree health, growth, nutrient cycle, soil parameters and soil organisms, ground vegetation, effects of pollutants and extreme weather events.
Our 188 permanent observation plots have more than 14’000 trees on. A large range of site conditions and pollution levels, enable epidemiologic data analysis and a transfer of experimental knowledge to forest ecosystems. Our results show that Swiss forests are strongly influenced by air pollution, including nitrogen deposition and ozone; and by increased drought stress due to climate change.