Swiss forests are exposed to changing environmental conditions. The consequences of air pollution and climate change on the forest are important questions which the Long-term Forest Ecosystem Research Programme LWF seeks to answer. Within a legally set framework of the LWF programme, Switzerland partakes in international research programmes such as The International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests ICP-Forests or the Long-Term Ecosystem Research LTER-Europe.