Forest Report 2025 ¶

Swiss forests perform a variety of services, including storing carbon and supplying renewable raw materials. The forest area has increased only slightly in the past decade, mainly at high altitudes where Alpine farming has been abandoned. The growing stock nationwide has remained constant at 420 million cubic metres. However, trends have varied from region to region. In the Alps and on the southern side of the Alps, the growing stock has increased, whereas there has been a slight decrease in the Jura and on the Plateau. These developments are due in particular to different intensities of use and to losses caused by climatic changes. The latter has resulted in a high mortality and increased salvage logging, with spruce and beech in climate-sensitive locations hit particularly hard. Structurally diverse forests and species-rich mixed stands can adapt better to climatic changes. They will also result in changes in the quantity and quality of timber supply. Young trees are the forest of the future. In order to maintain resilient forests with sustainable forest regeneration, the diversity of forest structures should be actively promoted. Adapting to climate change, for example by means of suitable tree species and forest structures, is a challenge that has to be addressed, because only a forest that is able to adapt can continue to provide its diverse services in the future.

Forest health and vitality is a valuable asset that can be jeopardised by environmental influences. Climate change is putting forests under pressure. In Switzerland, the average annual temperature has risen by 2 °C since pre-industrial times. Nitrogenous air pollutants and ozone still exceed critical loads and can make forests even more susceptible to drought. Extreme events such as heatwaves, droughts, hailstorms, storms and forest fires are on the rise, and the effects on forests are manifold. Earlier budburst, the risk of frost and lack of water impair vitality, i.e. the ability of trees to adapt and compete, with beech, fir and spruce particularly affected. Forests are becoming more susceptible to insect infestation and tree diseases, and trees are dying more frequently, in some cases over large areas. Globalised trade in goods is increasingly introducing non-native harmful organisms that can pose a significant threat to the forest ecosystem. Early detection is key to preventing their spread. Other measures can help make forests more adaptable, including planting suitable tree species, promoting site-appropriate mixed forests and increasing genetic diversity. Carefully planned test plantings provide important insights in this regard. A deeper understanding of processes and scientifically sound information about forest health and vitality are needed in order to develop suitable measures for sustainable management. This will enable forests to provide their ecosystem services in the future, even under changed climatic conditions.

Wood is the most important raw material in forests for humans. Forests also provide other products and services whose sustainable use needs to be carefully planned in view of climate change. Since 2015, some 5 million cubic metres of wood have been harvested and sold annually, around 66% of it coniferous (softwood) and 34% broadleaved (hardwood). The net increment, which in simple terms represents the growth of living trees, is declining for the first time in some regions due to increasing mortality, especially in spruce and beech. The proportion of salvage logging has risen significantly, especially at lower altitudes. As climate change leads to more frequent dry periods, the proportion of softwood in the timber harvest is also expected to increase in the future. In addition to wood production, forests provide a variety of other supply, regulatory and cultural services. Providing these services incurs costs that have so far only been partially covered. Forest ecosystem services include non-wood forest products such as forest mushrooms, game meat, forest honey and Christmas trees. These are gaining in importance and can be converted ever more effectively into financial value. Climate change and society’s growing demands on forests mean that forest planning is becoming more complex. It requires sound data collection and planning tools that are able to factor in all aspects of forest use.

The past decade has seen a slight improvement in forest biodiversity. Both the state and the development of biodiversity are generally better in forests than on open land. The diversity of gastropod (snail and slug), moss and tree species and the populations of most forest bird species have increased, while the situation of endangered forest species is  stable to slightly improved. This progress is due to the positive development of the overall ecosystem. Unnatural stands have decreased, while structural diversity and deadwood volume have increased. Forest reserves are approaching the target of 10% of forest area. Nevertheless, regional differences and deficiencies remain. On the Plateau, for example, 70% of stands have an unnatural proportion of spruce and are susceptible to disturbances. Meanwhile, 41% of forest communities – and thus the habitats of numerous species – are endangered. A high level of genetic diversity in trees would offer potential for adapting forests to climate change and should be taken into account in silvicultural strategies. The opportunities and risks of cultivating non-native tree species and of increased use of energy wood must be carefully weighed up with regard to the consequences for biodiversity. Biodiversity is the basis of forest resilience and is therefore essential for maintaining forest functions. However, climate change poses a challenge for maintaining biodiversity. Connecting forests in the landscape to allow species communities to adapt more easily to climate change is becoming increasingly important.

In Switzerland, 44% of forest protects people and infrastructure from gravitational natural hazards such as rockfall, avalanches and debris flows. Protective forests have become denser over the past decade, improving the protective effect. However, they have also got darker as a result. The lack of light and high levels of ungulate browsing prevent regeneration, meaning that in many places the protective effect is not guaranteed in the long term and takes longer to restore after a disturbance. Targeted regeneration interventions and adapted wildlife management can counteract this by achieving greater tree-species diversity, thereby ensuring protection against natural hazards even in a changing climate. Forests also protect groundwater, an important source of drinking water, from contamination. Groundwater from forest areas usually contains so few pollutants that it can be used as drinking water without treatment. However, in some places even forest groundwater exceeds the nitrate concentration limit of 25 milligrams per litre. To lower the nitrate concentration in groundwater and thus in drinking water, nitrogen deposition from the air must be reduced.

The forestry and wood industries provide a wide range of services for the Swiss economy and public. Equally, people and the economy greatly influence the use of forests and wood resources. The growing demands placed by the population on private and public forest owners and on forest multifunctionality have both advantages and disadvantages. On the one hand, additional sources of income become available, for example through carbon storage certificates. On the other hand, there may be trade-offs if multiple forest ecosystem services need to be provided simultaneously, e.g. raw wood production, recreational opportunities and protection against natural hazards. A further complicating factor is climate change, the effects of which require investments in forest adaptation. The increasing use of natural resources as part of the energy transition is also a challenge for forest management. Better cross-sector coordination and integration of policy is required to address this situation.