1. Traffic, agriculture, climate change, deforestation (drivers)

Increasing traffic volumes pollute the Swiss forest through emissions of nitrogen and other air pollutants, either directly from the air or indirectly through pollutant deposits in the soil.

Agriculture also contributes to the problem of nitrogen pollution, inter alia through the use of fertilisers.

Due to climate warming and the associated gradual and continuous changes in the climate, extreme weather events, for example heavy storms and summer heat waves, are likely to become more frequent in the future.

In the interest of forest conservation, deforestation is fundamentally prohibited in Switzerland; exceptional deforestation permits may, however, be granted if important interests are at stake that outweigh those of forest conservation. Examples include road and railway construction, landfill and mining projects. If deforestation is authorised, the deforested area must be compensated for through the afforestation of an equivalent area.

2. Nitrogen inputs, ozone, drought, insect infestation, recreation (pressures)

In 95% of forest area, the nitrogen inputs from the air are too high. Nitrogen causes the acidification of the forest and gives rise to an imbalanced supply of nutrients to the trees.

Leaf cells are also subject to attack from highly concentrated ozone in summer.

Higher temperatures and lower precipitation levels in the summer months combined with increased precipitation in the winter months have a direct effect on forests. Forest fires pose a risk during periods of drought, particularly in the Alps and Southern Alps. The risk of forest fires may change and proliferate due to climate change.

An unfavourable stand structure, in terms of the near-naturalness of the tree species and vertical structure, extreme weather impacts and newly introduced insect species can increase the vulnerability of the forest to pest infestation. The bark beetle, for example, can proliferate rapidly in storm damage areas.

Excessive recreational use of the forest in urban areas and in tourism areas can have impacts on forest regeneration and, hence also, on sustainable forest development and the behaviour of wild animals. 

3. Forest area increase, forest health, development of standing volume (state)

At approximately 1.3 million hectares, around one third of Switzerland is under forest cover. Switzerland's forest area increased by 4.9% between 1995 and 2006. This is due to the reclamation by forest of agricultural and alpine pasture areas in the Alpine region and the Southern Alps. Only 2% of the increase in forest area is accounted for by the afforestation of non-forest area. The pressure on forest area in the heavily populated Central Plateau remains high.

Models already exist that show how the forest line is retreating as a result of climate change and this will also lead to an increase in forest area.

Whereas the standing volume in the Southern Alps has increased by almost 20%, it has declined by around 7% in the Central Plateau. In the period 1995 to 2006, wood increment was 9.7 million m3. The total volume of harvested and fallen trees for the same period was 9.1 million m3.

Long-term studies have shown that the nutrient supply available to trees has deteriorated and trees are stressed as a result. This makes them more vulnerable to diseases and the impact of extreme meteorological events. This is evidenced, for example, by crown thinning which increased slightly form 1998. The heavy storms Vivian (1990) and Lothar (1999) caused windfall and wind damage over large areas. The heat wave of summer 2003 also weakened many trees considerably. Damage caused by harmful insects, in particular the bark beetle, arose as a result. 

The forest is very important for species diversity. Almost half of the flora and fauna in Switzerland, i.e. 20,000 species, depend on it. The maintenance of a balanced and near-natural distribution of tree species has positive effects on both biodiversity and the stability of the forests.

Despite its generally positive situation, the Swiss forest also has ecological deficits. There is too little dead wood in some areas which is essential to the survival of thousands of species.

4. Less stability, change in forest biodiversity, CO2 sinks (impacts)

The undesired input of nutrients from the air causes trees to grow faster in height without forming correspondingly deep roots. This reduces the stability of the forests.

Ozone pollution causes leave and needle damage to trees in the forest. Some polluted forests cannot adequately fulfil their function as groundwater filters. In many locations, the forest structure does not provide optimal conditions for the conservation of biodiversity.

Climate change affects forests as ecosystems and the growth of individual tree species: forest communities change and the forest line shifts to higher altitudes. Although forests and tree species can adapt to altered conditions over the generations, this capacity is coming under pressure due to the speed at which climate change is taking place.

The increase in forest area can have both positive and negative effects, the impacts of which are mainly felt at local and regional levels. Together with the segregation of agricultural production land, this results, for example, in the disappearance of traditional landscape forms which are perceived as particularly attractive, such as the wooded pastures (Wytweiden) in the Jura region.

On the other hand, large forest areas can absorb more CO2 from the atmosphere, a process that counteracts the greenhouse effect. Forests act as carbon sinks and contain four to five times more carbon than the atmosphere over our country.

Increasing forest areas in the mountain regions can also provide greater protection against natural hazards.

5. Deforestation ban, forest development plans, certificates and forest reserves (responses)

The most important forest protection measure in terms of forest area is the legally prescribed ban on deforestation.

The cantonal forest development plans are intended to ensure that the sustainability of forest management is guaranteed.

The awarding of certificates (FSC label at international level and Q label at national level) by the international label organisations for wood that is produced in an environmentally-friendly and socially-responsible way contributes to the protection of the forest.

Biodiversity is protected in forest reserves. Switzerland has 800 forest reserves, which represent 3.5% of the total forest area. The federal authorities and cantons aim to increase this to 10% by 2030. Wood harvesting is severely limited or prohibited in these forest reserves in accordance with their protection aims.

Measures for the protection of the air and regulations on pollutant emissions from heating systems, industrial plants and motor vehicles and on the quality of motor fuels and heating fuels contribute to the conservation of the  good health of the forest. In order to stabilise the state of the forest, nitrogen and ammonia emissions should be reduced at source in accordance with and through the application of the relevant legal provisions.