Large-scale forest condition monitoring (Level I)

Level I monitoring provides an annual overview on forest condition based on a 16x16 km gridnet covering around 6000 plots in Europe. In addition soil and foliar analyses are carried out

Crown condition assessments

Crown condition at Level I has proven to be a valuable tool for detecting status and trends of tree condition in Europe. It is assessed annually at the European level on all 16 * 16 km Level I points. The main parameters to be assessed are:

• Defoliation (percentage of leaf or needle loss)
• Discolouration
• Damages visible on the trees

Soil condition assessments

There are clear correlations between the deposition of air pollutants and forest soil chemistry. Its condition is essential for many organisms living in the soil and for forest functions like water storage and filtering. Nutrient imbalances in the soil are linked to tree health and condition. Soil condition has been asessed on around 5300 plots in the 1990s. A new assessment is presently carried out within the BioSoil demonstration project.

Foliar survey

Changes in environmental conditions may may affect foliar nutrient concentrations. The monitoring of tree nutrition is thus essential for assessing forest condition. A foliar survey in the 1990s has covered appoximately 1400 plots. A number of countries are carrying out repeated foliar surveys.