International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests-ICP Forests-

Abstract

ICP Forests was launched in 1985 under the Working Group on Effects of the Convention on Long-range Transboundary Air Pollution of UN/ECE. As part of the Programme, forest condition is surveyed annually on up to 33,600 sample plots with about 622,000 sample trees in 35 countries, representing about 225 million hectares of forest. Results of the national surveys are reported as country related mean values, split into tree species and age groups. A special transnational survey is performed in cooperation with the European Commission, based on a uniform 16 × 16 km grid of 4,800 plots with 103,000 trees in 27 countries. Results show that large scale forest decline has been less dramatic than was suggested in the early 1980s. Nevertheless, a general worsening of forest condition can be shown in many parts of Europe. In some areas, particularly in Central and Eastern Europe, several thousand hectares of forest have died. Whilst the most important probable causes reported for the observed forest damage are adverse weather conditions, insects and fungi, most countries consider air pollution as a threatening to forest health.