Water quality effects of final felling in Finland and Scandinavia - a review

Swedish Skogforsk and Finnish LUKE will review current literature on final fellings’ effects on hydrology and water chemistry. The study is funded by Swedish Skogssällskapet and focus on Finnish and Scandinavian forestry.

Forest biomass is generally considered sustainable, and the demand for renewables increases to substitute fossil fuel dependency. Clearcut forestry with final felling is the dominating harvesting method in Sweden and Finland. Environmental consequences have been studied here and across the world.

Final felling affects various aspects of the local environment, for example regarding hydrology, soil- and water chemistry, as well as microclimate. Final felling can alter hydrological flow paths, runoff volume and regime, often leading to leakage of humus, nutrients and metals.

Sustainability in the forestry sector is necessary to secure the needs of future generations in terms of monetary values, biodiversity, as well as recreational demands, as noticed by the United Nations in the 1987 report Our Common Future.

Studies have indicated different magnitudes of impact from final felling in different landscapes and at different seasons. Felling methods and mitigation measures have also generated various results for the environment. By comparing these studies, we attempt to identify patterns and seek explanations to the variations in results, e.g. among methods and seasons, soil disturbances, previous fertilization, local differences in geology, meteorology, and biological conditions.

The objectives of this study are to review and synthesise the current knowledge about the environmental impacts of final felling and identify knowledge gaps.