Forest ecosystem conditions

Major pressures affect the forest and their ecosystems. The European member states record the following forest health indicators in a harmonised way: tree crown condition, soil condition and foliar nutrient content.

Foliar nutrient condition


Tree crown condition, %

Defoliation is defined as needle/leaf loss in the assessable crown as compared to a reference tree. Defoliation is observed regardless of the cause of foliage loss.

Trees are moderately to severely defoliated when defoliation exceeds 25%.


Main disturbances on forest ecosystems

The main disturbances on forests comprise forest fires, diseases, insects and storms.

Forest area affected by fires, k ha

The occurrences of forest fires have varied over the last 20 years with high occurrences in 2000, 2003, 2012 and 2017.


Forest area affected by pathogens, k ha

Damage from disease increased in the last few years.


Forest area affected by insects, k ha

Damages from insects have increased steadily. In 2017, it affected 10 times more forest area than ten years ago.


Forest area affected by severe weather, k ha



Deforestation is defined as the permanent conversion of forest land to agriculture, grassland, wetland and urban areas. Deforestation covers forest areas where the impacts of disturbance, over-utilisation or changing environmental conditions affect the forest to an extent that it cannot sustain a canopy cover larger than 10 percent.

Deforestation, k ha


Forest fragmentation

Forest fragmentation is breaking large, contiguous forested areas into smaller forest patches, separated by roads, agriculture, utility corridors or other anthropological developments.

Fragmentation is one of many factors that threaten forest health and vitality. Large and intact forest ecosystems are essential to maintaining a good forest condition and biodiversity. Increased fragmentation means that the forest area in the largest patch sizes will decrease and that the small size classes will increase.

Share of different forest patch sizes in 2018, % of total forest cover