Increasing forest connectivity is crucial for supporting biodiversity. Fragmentation of forests is the main factor limiting their connectivity. In 2018, the EU’s average forest connectivity was 79%. The indicator is, at present, limited to that year. Forest connectivity shows no significant changes from 2000 to 2018. The EU Forest Strategy for 2030 and the EU Biodiversity Strategy for 2030, which includes a pledge to plant at least three billion additional trees by 2030, promote forest connectivity. However, the effects of these policies will take time to become visible, making an increase in forest connectivity somewhat unlikely by 2030.

Figure 1. Forest connectivity in EU member states
Forest connectivity in EU member states

Forests have significant cultural and economic value and are vital in supporting biodiversity and human well-being. Historically, forests have become fragmented due to conversion to cropland and pastures, urbanisation and infrastructure developments .

Maintaining forest connectivity and avoiding forest fragmentation benefit species that thrive in a larger area and enable species dispersal . Forest patches and woody features such as hedges and tree lines can play a key role in bridging gaps between forests, enhancing connectivity and movement of species between suitable habitats.

The EU Forest Strategy for 2030 , the EU Biodiversity Strategy for 2030 and the pledge to plant at least three billion additional trees by 2030 , highlight the importance of expanding tree and forest cover to safeguard biodiversity.

The forest connectivity indicator measures the degree of forest density. The indicator shows the percentage of forested land not covered by any forest or woody features within a 10-hectare area surrounding a 100m2 forest grid cell . The indicator assesses the forest’s structural connectivity on a grid, meaning it provides a general insight into the environment’s capability to connect local habitats regardless of the type and quality of the forest, rather than to specifically account for the needs of individual species or species groups.

In 2018, the average forest connectivity index for the EU was 79%. This indicates that on average, 79% of the 10ha area surrounding a 100m2 forest pixel was covered by forest or other woody features. The indicator is calculated only on cells of the grid covered by or adjacent to forest land. The indicator shows an average degree of forest connectivity (see Figure 2). However, any statistically averaged indicator value averages out spatial variability and conceals instances where forests can be disconnected or poorly connected. Consequently, regions with large extents of continuous forest cover highly influence the EU average value.

This indicator does not provide a historical trend as data are available only for 2018. However, it uses a similar methodology as the fragmentation indicator reported in Forest Europe , Vogt et al. , Maes et al. , and Vogt and Caudullo . Although these indicators are calculated using different underlying data and resolution, they provide insights into past trends in forest connectivity, which remained relatively stable between 2000 and 2018.

Assessing the prospects for improved forest connectivity by 2030 is challenging and past findings do not show significant changes . The effects of implementing the EU’s forest and biodiversity strategies - such as promoting afforestation, reforestation, and restoring forest ecosystems - will most likely only become visible after 2030 due to the time lag between actions in the field and increased connectivity. However, actions to increase forest fragmentation, such as deforestation or removing connecting hedges and tree lines, can have immediate effects.

Figure 2. Share of forest area by forest connectivity classes and average forest connectivity in the EU Member States
Share of forest area by forest connectivity classes and average forest connectivity in the EU Member States
CountryVery low (<10%)Low (10% to <40%)Intermediate (40% to <60%)High (60% to <90%)Very high (≥ 90%)Average forest connectivity across the country

Forest connectivity in the EU Member States correlates strongly to the presence of large forest areas (displayed by the class ‘very high connectivity’). In Member States with smaller and fewer continuous forest patches, forest strips play an important role in maintaining connectivity (classes ‘low’ and ‘intermediate’ connectivity).

This indicator relies on a map of forest area density at fixed observation scale, prepared following a methodology developed by the European Commission’s Joint Research Centre. With this approach, large forest patches show high connectivity (includes not only forest, but also woody features such as treelines). Therefore, most connectivity estimates at the country level range from 70% to 86%. Based on the country quintiles, an indicator above 84% may be considered very high and an indicator below 72% may be considered very low connectivity. The EU average is highly influenced by areas with large continuous forest blocks, mainly in Slovenia, Romania, Finland and Sweden. Few countries show average connectivity below 70%. Experts from a number of EEA Eionet countries have, however, expressed significant reservations concerning the methodology of this current indicator and its ability to properly assess progress towards policy objectives concerning forest connectivity. Reflecting these concerns, the EEA is working to develop an improved indicator to better represent connectivity at both country and EU level.