Satellite data shows: 900,000 hectares of forest lost

According to the latest satellite data, the tree population in Germany is continuing to shrink dramatically. According to the German Aerospace Center (DLR), more than 900,000 hectares of forest were lost between autumn 2017 and autumn 2024. This corresponds to around 8.5 percent of the total German forest area. The losses have almost doubled since 2021, as the DLR demonstrated. However, according to the DLR, the data does not take into account possible re-growth, as the young plants were still too small during the seven-year observation period.

According to the satellite data, the Harz Mountains, south-westphalia, the south-east of Thuringia and the border region between Saxony and the Czech Republic were particularly badly affected by forest damage. There, the proportion of so-called "canopy loss" in relation to the entire forest was well over 50 percent in some municipalities. In some municipalities, such as the town of Oberharz am Brocken, it was even over 61 percent.

Central Germany is particularly affected

"Environmental influences and pest infestations have left their mark on our forests," said Anke Kaysser-Pyzalla, Chairwoman of the DLR Executive Board. Unusually severe periods of drought, heat waves and storms have taken their toll on Germany's forests in recent years. The stressed trees are also susceptible to pests, so that in many places trees are dying and in some cases large areas have to be felled. The German Aerospace Center has launched a new online platform that gives the timber industry, local authorities and politicians access to the data so that they can respond better to the decline in the forest.

A study conducted by the Helmholtz Institute for Environmental Research (UFZ) last year also showed that central Germany is particularly affected. According to the analysis, regions such as the Harz Mountains, the Thuringian Forest, the Sauerland and Saxon Switzerland showed increased forest damage from 2019 onwards. The damage was particularly severe in the forests of the low mountain regions where spruce trees were planted after 1945. However, pine, beech and oak trees also suffered heavy losses in some regions. However, the new DLR satellite data also shows that forest losses were not only recorded in the drought years between 2018 and 2021, but that the forest loss also continued afterwards.

Only one in five trees without crown damage

However, there are different figures for forest loss in Germany based on the area of damage. The Thünen Institute, which compiles the annual forest condition report, put the area to be reforested after damage at around 490,000 hectares. Last year, the Association of Forest Owners estimated around 600,000 hectares. According to experts, the 900,000 hectares determined by the DLR also includes areas that have either already been reforested or where trees have been felled by human intervention, for example by forestry or to prevent the spread of pests.

The satellite data now published supplements the annual forest condition survey carried out by the Thünen Institute on behalf of the Federal Ministry of Agriculture. Each year, the crown condition and thus the vitality of German forests is assessed in a systematic sampling network. According to the most recent report, only around one in five trees in Germany had no crown damage.

Weather stress for forests remains high - adapted measures necessary

In the opinion of the DLR, extreme weather events such as unusually severe droughts and heat waves will continue to increase in view of global change. The spruce forests that dominate Germany, for example, have already suffered drastic losses due to the dry heat and the resulting bark beetle populations - this trend is expected to continue in the coming years.

It is therefore essential for forest management to predict such trends. Long-term satellite data time series make it possible to continuously monitor the large forest areas and recognize changes. "The data to date clearly shows that pure cultures of spruce, pine and beech are particularly at risk," the DLR reported. Mixed forests, on the other hand, are more resilient and have a better risk distribution. Biodiversity and a mixed forest structure with both young and old trees are therefore key to healthy forests.