Forest condition survey (1987-2006)

The Forest Condition Survey has been carried out since 1984 and, in addition to providing comprehensive information on tree health in Britain, it contributes to an EU programme monitoring the health of a forest area of over 150 million hectares. As well as detecting, quantifying and determining the causes of short-term damage to trees, the presence of long-term trends in the condition of particular tree species can also be detected by the survey. The Forest Condition Survey therefore plays an important role not only in the immediate identification of particular tree health problems but provides information of relevance to studies of pollution effects, climate change and sustainable forest management.
The Forestry Commission initiated the first survey of forest health in Britain in 1984, assessing the condition of Sitka spruce, Norway spruce and Scots pine. By 1987, the programme had been expanded to include oak and beech and the age range of the trees assessed in the survey had been widened to incorporate older crops of the coniferous species. Plots were also established on private land to increase the survey’s geographical coverage and to provide a more representative sample of British forests.
Forest decline was linked with air pollution by certain scientists and foresters during the 1980s. Concern over atmospheric pollution had already given rise to the Convention on Long-Range Trans-boundary Air Pollution (CLRTAP) in 1979 and, under its auspices, an International Cooperative Programme on Assessment and Monitoring of Air-Pollution Effects on Forests (ICP-Forests) was set up in 1985. In co-operation with the European Commission (EC), which introduced legislation requiring member states to undertake forest health monitoring programmes in 1986 (Regulation EEC No. 3528/86), an extensive network of forest monitoring plots (the Level I network) was established. By 2002, 17 countries from outwith the EU and 15 EU member states including the United Kingdom were contributing to an ICPForests Level I network consisting of approximately 132 000 trees located in 5900 plots and representing a forest area of over 150 million hectares.
The Forest Condition Survey, including its Level I component, provides a national overview of forest health in Great Britain. Focussing on a key selection of forest tree species over a wide geographical range, the survey continues to gather a unique time series of forest health data.
This information not only fulfils the UK’s international obligations to provide data on forest condition and indicators of sustainable forestry but also supports national forestry policy, the UK Forestry Standard and the UK Woodland Assurance Scheme. Whilst originally established to address the potential effects of air pollution on forests, the Forest Condition Survey was responsive to changing requirements for data on tree health.
See also Hendry (2004) “Monitoring of forest health in Britain: The Forest Condition Survey and Level I networks” Forest Research Annual Report and Accounts 2003-2004 Attribution statement: © Forestry Commission copyright and/or database right 2025.  All rights reserved.

Tags: Tree condition, Tree health, UK, damage, environment, plant health care, pollution, research, survey
Organization: Forestry Commission