Monitoring

The active participating countries gather data of the crown condition of forest trees on about 6,000 plots every year. In addition, they examine the forest soils approximately every 10-15 years and measure the nutrient balance of trees. This is called Level I monitoring.

Since 1995, intensive Level II monitoring has also been carried out on more than 600 plots across Europe. The surveys cover air quality, deposition, soil water chemistry, weather conditions, ground vegetation, tree growth, phenology, litterfall composition and visible ozone damage. Level II monitoring helps to identify the influence of air pollutants and climate change on the condition of forests and their spatial and temporal changes.