Background to the intensive long term monitoring of forest ecosystems programme

 

First national survey of tree health

In the early 1980s, widespread forest decline became a matter of concern for foresters and scientists across Europe. Many countries established surveys to assess the condition of their forests. The Forestry Commission embarked on the first national survey of tree health in 1984 (Binns et al., 1985). This survey has been repeated annually, and currently assesses a total of 8735 trees of five species in 364 plots (Redfern et al., 1999). The results are reported in Information Notes issued by the Forestry Commission.

Level I programme

Under initiatives by the United Nations Economic Commission for Europe (UN/ECE), the various national surveys were incorporated into a large-scale pan-European survey of forest condition in 1987. This became known as the 'Level I' programme, with the major aim of monitoring crown condition changes over a long period of time in a large number of forest plots. There are now 15 European Union (EU) and 19 non-EU country participants in the Level I programme. In total, the crown condition of almost 100 000 trees are assessed annually in around 5400 plots, representing almost 200 million hectares of forest in Europe.

Level II programme

The Level I network provides accurate information on the extent and spatial distribution of crown condition in Britain and Europe, and a database for analysis of changes over time. However, it cannot identify cause-effect relationships. It does not determine the extent to which air pollution and other stress factors are responsible for the health, or ill health, of forest systems. To achieve this, a second series of plots for intensive monitoring of forest growth and condition, and the environmental conditions which cause them, was initiated under European legislation in 1994. This is known as the 'Level II' programme (European Commission and ICP Forests of UN/ECE,1996).