Europe’s record forest biomass loss comes with hidden risks for slopes, roads and drainage systems

Europe’s forests are losing above-ground biomass at an increasing rate, with a clear deterioration recorded since 2018. An ESA-supported study published in Nature Geoscience found that forest disturbances are now removing more biomass per hectare than previously understood, especially in older and biomass-rich forests.

Europe’s forests cover about 39 percent of the continent’s land area and store around 10.6 billion tonnes of carbon in above-ground biomass, including trunks, branches and leaves. Between 1985 and 2023, disturbances such as logging, wildfire, pests and wind damage caused an estimated 6.5 billion tonnes of above-ground biomass loss across Europe, although some of this has since been offset by forest regrowth.

The important change in the new research is that it does not only measure the area of forest affected. It also estimates how much biomass was lost. This distinction matters because two disturbed areas of the same size can have very different carbon impacts. A fire in open Mediterranean woodland may remove far less biomass than a disturbance affecting a dense, mature forest in central Europe.

The study found that, for each hectare of disturbed forest, biomass losses have increased by 46 percent since 2018. Across Europe, annual biomass losses from harvesting and natural disturbances were 30.8 percent higher in 2018 to 2023 than in 1985 to 2017. Losses from natural disturbances alone increased by 45.5 percent.

The strongest increase was recorded in temperate forests of central Europe, particularly in Germany, Czechia and Poland. Severe drought between 2018 and 2022 weakened trees and contributed to large bark beetle outbreaks, especially in forests dominated by susceptible species such as Norway spruce.

Logging still accounted for the largest share of biomass loss, around 82 percent over the full study period. However, natural disturbances were responsible for much of the recent acceleration. This is why the trend is significant. Even where the disturbed area does not increase dramatically, biomass losses can rise sharply when high-carbon forests are affected.

A second ESA-supported study published in National Science Review reached a related conclusion. It found that Europe’s forest carbon sink may decline by 39 percent between 2010 and 2030 because disturbances and harvesting are outpacing natural regrowth and recovery.

Earth observation is central to this work. The study combined annual tree-cover loss maps derived from the Landsat archive with high-resolution biomass data to reconstruct forest biomass losses over nearly four decades. ESA also reports that Copernicus missions are now widely used to monitor wildfires, drought and heatwaves.

In 2026, extreme heat, dry ground and low soil moisture have created favourable wildfire conditions across parts of Europe. Since 1 May 2026, the Copernicus Emergency Management Service has been activated more than 30 times for wildfire mapping in countries including Croatia, France, Germany, Greece, Italy, Portugal, Spain and the UK.

The final implication is that forest disturbance can also become a ground stability issue. After wildfires or severe vegetation loss, slopes may lose root reinforcement and protective ground cover, while rainfall runoff and erosion can increase. In steep terrain, this can raise the risk of debris flows, shallow landslides, blocked culverts and sediment impacts on roads, railways and settlements below burned catchments.