The restoration of drained peatlands aims to restore peatland ecosystems damaged or destroyed by drainage to a condition similar to their natural state. This is achieved by filling ditches and removing trees, which helps to raise the water level in peat and the succession of species.

Photo: Anne Tolvanen, Luke
Photo: Anne Tolvanen, Luke

Studies have shown that, in most cases, the water level in peatlands is rapidly restored to that of undrained mires, but processes in peat and vegetation are triggered at a slower pace. However, progress is heading towards the desired direction:  slower decomposition releases nitrogen more slowly for plants, the coverage of forest species decreases and that of mire species increases. Blocked ditches are overgrown by mire mosses.

After restoration, young peatlands on the coastal land uplift region recover faster compared to peatlands which developed after the end of the Ice Age along the current eastern border.

Restoration has adverse impacts on the environment, at least in the short term. Disturbances in nutrient cycling caused by the blockage of ditches increase the nutrient loading to nearby waters. Greenhouse gas emissions may also increase in the short term. Little information exists so far on the long-term restoration success. It is therefore not known, whether restoration returns the slow processes typical for mires or whether it forms totally new mire types.

Many peatlands require restoration

More than half of the almost 10 million hectares of peatlands in Finland have been drained for forestry use. However, timber production has remained low on almost one fifth of these peatlands, mainly due to the nutrient-poor soil.

The Natural Resources Institute Finland is involved in activities such as the large-scale LIFEPeatLandUse project, funded by the EU LIFE+ Environment programme, which produces information on alternative uses for the low-productive drained peatlands, and their environmental and economic impacts. Luke is coordinating the project, in which the universities of Helsinki and Oulu, Metsähallitus, the Finnish Environment Institute and Vapo Oy are partners. The project receives additional funding from the Ministry of the Environment and Turveruukki Oy.

Picture on top of the page: Juha Siekkinen