International Day of Forests

Air pollution not only endangers human health but also affects forests. Scientists at the Thünen Institute of Forest Ecosystems are investigating the consequences for trees. As part of the ICP Forests research program, Thünen researcher Kai Schwärzel heads the Programme Co-ordinating Centre in Eberswalde. This is where Europe-wide forest monitoring data is collected and analyzed. Based on these results, policymakers can make decisions in line with the Convention on Long-range Transboundary Air Pollution. At the annual meetings of the UNECE Air Convention in Geneva, Kai Schwärzel presents the latest status report, including next week at the Extended Bureaux Meeting.

The latest results from long-term measurements in European forests show that the air pollution control measures of the past decades have been successful. For example, sulfur deposition from the air in the Eastern Ore Mountains has decreased by more than 94 percent since the 1970s. This has also altered the nutrient balance in the forests. “Plants need sulfur to maintain their metabolism and defense mechanisms. That is why it is important to monitor the supply of sulfur and other nutrients to our forests and provide targeted support,” explains Kai Schwärzel. Since the 1990s, the ICP Forests network has been providing data on the nutrient composition of tree leaves and needles, thereby offering one of the world’s highest-quality long-term datasets on the nutritional status of European forests.

The International Co-operative Programme ICP Forests was founded in 1985. Its goal is to make information about the condition of forests accessible to the scientific community, policymakers, and the public—based on high-quality, freely available data. To this end, researchers use standardized methods to assess the condition of forests in approximately 6,000 study sites across 40 European countries, as well as the United States and Canada. In addition, the team at the Programme Co-ordinating Centre supports expert panels with technical questions and conferences and contributes its expertise to international studies.