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ICP Forests

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

Chair: Mr. Michael Köhl

Head of Programme Co-ordinating Centre: Mr. Walter Seidling


ICP Forests was launched in 1985 in response to wide public and political concern over extensive forest damage that had been observed in Europe in the beginning of the 1980s.

The objectives of the Programme are:

•    To provide a periodic overview on the spatial and temporal variation of tree crown condition (an indicator of forest health) and foliar element concentrations of forest trees, as well as forest soil condition (solid phase) in relation to anthropogenic (in particular air pollution) and natural stressors across the UNECE region.
•    To gain a better understanding of the cause-effect relationships between the condition of forest ecosystems in terms of health, productivity, diversity and nutrition, and anthropogenic (in particular air pollution) as well as natural stressors in forest ecosystems across the UNECE region.

ICP Forests is steered by a Task Force in which at present 42 participating Parties are represented. It operates under the leadership of Germany and is coordinated by the Programme Co-ordinating Centre at the Thünen Institute of Forest Ecosystems, Eberswalde.

ICP Forests monitors and evaluates forest condition in Europe at two monitoring intensity levels:

•    The Level I monitoring is based on around 6000 observation plots on a systematic transnational grid of 16 x 16 km throughout Europe to gain insight into the geographic and temporal variations in forest condition.
•    The Level II intensive monitoring is carried out on around 500 permanent observation plots installed in selected forest ecosystems distributed across the UNECE region. Surveys to assess cause-effect-relationships include: ambient air quality, crown condition, deposition, foliar chemistry, ground vegetation, leaf area index (LAI), litterfall, meteorology, phenology, visible ozone injury, tree growth, soil condition, soil solution chemistry.

All data are available for research purposes on request. For further information, please contact the Programme Coordinating Centre (PCC).