Clean drinking water thanks to intact forests

Without forests, Switzerland's drinking water supply would be at risk: This is reminded by the Association of forest owners on the occasion of Forest Day on March 21. Around 40% of Switzerland's drinking water comes from the forest. This acts on the one hand as a rainwater reservoir and on the other hand as a drinking water filter.

Compared to groundwater from agricultural or settlement areas, drinking water has fewer pollutants. According to the association, this is due on the one hand to the renunciation of fertilizers and pesticides as well as rarer incidents involving pollutants in the forest, and on the other hand to the sustainable management of the Swiss forest by its owners: For example, domestic forestry uses biodegradable and low-pollutant fuels and lubricants, does not carry out large-scale logging, and takes care of the forest floor, e.g., by driving through the forest only on defined paths as a matter of principle.

Stable forests ensure water quality
Forest soils are therefore not very compacted and, with their high humus layer and good root penetration, contribute significantly to water treatment. In complex mechanisms and chemical processes, the water is purified from possible pollutants such as pesticides, fertilizer substances, but also germs. In addition, the widely ramified and multi-layered root system of the forest plants ensures that water can penetrate well into the soil and be stored there - up to 2 million liters of water per hectare.

In order for the soil to fulfill its filtering and storage capacity optimally, active and prudent forest management is advantageous. For example, an appropriate proportion of hardwoods influences the positive effect. In addition, regular maintenance and harvesting interventions keep forests stable and less vulnerable to storm events. The tearing up of the forest floor by falling trees can thus be avoided and extensive collapses with subsequent nitrate release in water protection zones can be prevented; the overall structure of the natural filter remains intact and efficient.

Compensation demanded

However, according to the Association of Forest Owners, the efforts made by the Swiss forestry sector to protect drinking water are not sufficiently compensated. It therefore advocates compensation for the forest's drinking water services and the associated additional expenditure. Because, it concludes, the beneficiaries (drinking water catchments) save millions in treatment costs every year, while the majority of forestry operations make losses in the forest.