Leaching

Increased leaching, a problem in Finland

Most of the river basins in Finland drain to the Baltic Sea, where the water quality is poor due to the eutrophication, caused mainly by agriculture, industry and housing. .

Forest operations have a minor role, for example, 7percent of the phosphorus and 5 percent of the nitrogen load into water courses results from forest operations.

On national scale the background leaching of nitrogen and phosphorus from the large forest areas has a bigger importance than the increased leaching caused by the forest operations. However, the forest operations have a significant impact on the water quality in headwater streams and lakes, especially in the areas where forestry is the main land use.

Cuttings and maintenance of ditches affects the water

Final cuttings associated with soil scarification, and ditch network maintenance are the forest operations which have major impacts on water quality in Finland. The increased leaching of suspended solids, nitrogen and phosphorus are causing the biggest problems in waters.

The ecological status in 85 percent of the lakes is classified as good or better according to the classification system developed for the implementation the EU Water Framework Directive. Only in 68percent of the rivers the ecological status is good and it is poor in many rivers draining to the Baltic Sea.

Water protection is planned before forest operations

Measures to decrease leaching

Several measures are carried out to decrease nutrient leaching and soil erosion after forest operations. Water protection is planned before the operations. In harvesting and soil scarification buffer zones are left between the managed areas and water bodies. In ditch network maintenance sedimentation ponds and pits, peak runoff control and surface runoff areas are used to stop the sediment transport and to some extent also the transport of dissolved nutrients.

WAMBAF will provide us new tools for planning water protection in harvesting and ditch network maintenance operations. We will also demonstrate and train their use in practice. It is important for us to work together with the other Baltic Sea countries in developing water protection measures and guidelines, and to implement the best available water protection practices within the Baltic Sea Region.

Facts about lakes and forests in Finland

Number of Inland lakes: 56 000

Length of rivers: 53 000 km
Annually final cuttings: 140 000 ha
Ditch network maintenance: 60 000 hectares, covering <1percent of the forest area.

Forests in Finland cover 74 percent, of the land area and they are mostly managed for forestry purposes. Protected and maintained pristine forests: 12 percent, 1/3 of the land area (9 Mha) is covered by peatlands. Half of the peatlands are drained for improving forest growth.

Lena Finér

  • Last Updated: 4/6/2017