Over the past decade, extreme events such as heat, drought, storms and pests have taken a heavy toll on Swiss forests. In order for forests to continue to fulfil their functions for people and the environment in the future, they must be made more resilient to climate change. This is the conclusion of the 2025 Forest Report published by the Federal Office for the Environment FOEN and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL.

Switzerland's forests fulfil a wide range of functions that benefit both humans and the environment. They protect people, property and infrastructure from natural hazards such as landslides, avalanches and rockfalls by preventing or slowing them down. They clean water and currently store more CO₂ from the atmosphere than they release. Wood can be used to replace energy-intensive building materials such as reinforced concrete. Furthermore, the forestry and timber industry employs a significant workforce.

In order to obtain a comprehensive picture of Switzerland's forests, they are monitored on a long-term basis. On 18 March 2025, the Federal Office for the Environment FOEN and the Swiss Federal Institute for Forest, Snow and Landscape Research WSL published the Forest Report 2025, which is the result of the last ten years of monitoring. The report provides information on the state of and developments in the forest and highlights the challenges (see box).

Forest health weakened in many places

Over the past ten years, there have been more extreme weather events, which is one of the effects of climate change. The increased frequency of droughts, storms and forest fires, in combination with harmful organisms and high nitrogen inputs, are affecting forests, so that their overall condition is now considered to be weakened. In some regions, such as the Jura, it is even classified as ‘critical’.

This also has consequences for forest management and thus for the entire value chain of the timber industry. Weakened forests lose their resilience and are more susceptible to diseases and pests such as bark beetles. As a result, there has been an increase in the number of cases of forced utilisation, in which damaged or fallen trees have to be harvested earlier than originally planned, e.g. for energy generation by incineration instead of being used to manufacture wood products.

Forest biodiversity is trending positively

Forests are an important habitat for animals and plants. Around 40 per cent of the species recorded in Switzerland live in or off the forest. Biodiversity in the forest has trended slightly positively, with increases particularly in the number of forest birds, snails and mosses. Storms and drought have led to more deadwood, which is vital for many species. In addition, forest owners are leaving more of it in the forest. The protected areas in the forest have been expanded from 5 per cent to 7 per cent of the forest area over the past ten years.

Despite this positive development, 13 per cent of forest plants and almost half of the wood-dwelling beetle species are endangered. It is therefore important to promote biological diversity. To do this, forests must be used in a near-natural way, endangered habitats must be protected and forest areas must be better connected.

Adaptation is the greatest challenge

In order to maintain the forest as a healthy and resilient ecosystem and timber supplier in the long term, tree species are needed that are resistant to climate change and harmful organisms. In addition, forest management should promote the diversity of forest structures, for example by choosing sustainable, climate-adapted tree species or through forest rejuvenation. To reduce game browsing (such as deer eating of young plants or parts of them), game populations must be regulated.

The Forest Report provides a scientifically sound basis for the development of the Integral Forest and Wood Strategy 2050, on which the Federal Council will decide in 2025.

About the Forest Report 2025