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Size: 3343 hectares
Conservation status: NATURA 2000, SPA, Läänemaa-Suursoo Landscape Protection Area
Habitat types: Degraded Calcareous fen (7230), Transitional and quaking mires (7140), Active raised bogs (7110*), Bog Forests (91D0*), Fennoscandian deciduous swamp woods (9080*), Western Taïga (9010*)
Climate: Cool temperate climate
Temperatures: Ø January: -3°C, Ø July: 17°C
Precipitation: Ø 696 mm/year

Project site

The degraded Suursoo fen forms the eastern part of the Läänemaa Suursoo mire complex, which is located in northwestern Estonia and covers over 20.000 ha. All mire habitat types within the project site were strongly damaged by drainage, and their ability to accumulate peat was affected. Only the very northern section (200 hectares) continued with peat accumulation. The peat forming mosses were scarcely distributed. Dominating purple moor-grass (Molinia caerulea) indicated the significant seasonal water level fluctuation amplitude (over 0.5 meters). Near the ditches, which extended for over 38 kilometres, the growth and density of the tree coverage increased, as can be observed in the aerial image from 2016, prior to the restoration measures. Before drainage, the project site was a wet and seasonally flooded alkaline fen with up to 4.8 m layer of fen peat.

Restoration measures

A total of 173 dams and 12.4 km of peat dikes were built to block the 45 km long ditch network. Additionally, a 2.7 km long overgrown section of the Kaldemäe strem was opened for fish migration. The dams and peat-dikes is expected to reduce the effect of drainage by raising the groundwater level and shortening the dry period. Find a more detailed overview of the restoration works implemented in the project site here.



Estonia is situated in the nemoral-submeridional fen and raised bog region. According to Ilomets (2017) the total mire area is 310,000 to 340,000 hectares. Peatlands with more than 30 centimeters depth are covering an area of about 915,000 hectares (1).

Peatland use

Exploitation of mires for agriculture and peat extraction started in the 17th century (4) but intensified by the end of the 19th and the beginning of the 20th century, when over 350,000 hectares of organic and wet mineral soil was drained (Ratt 1985). As the hand-cut ditches were only 50 centimeters deep, the drainage impact was modest (6). After the World War II drainage for agricultural purposes was intensified.

Draining of mires for forestry commenced at the beginning of the 19th century, became more systematic after 1830-1840, but remained at a low level until after World War II. In 1918-1940 forestry accounted for some 15,000 hectares of drained peatlands. After the 1950 there was a significant increase in mire drainage. By 1992 560,000 hectares of peatland forests were drained (Pikk 1997) that makes up to 90 percent of former peatland forests.

Mire conservation

Mire conservation dates back about 100 years ago. Since then several mire reserves have been established. The most comprehensive was the conservation efforts in the 1970s, when 30 mire reserves (largely bogs) with a total area of 122,000 hectares were established. As all fens belonged to the ‘potential amelioration fund’, they were not included except for one – the largest (6,000 hectares) yet undrained fen site, the Avaste fen (Kask 1965).

Considerable parts of the fens disappeared due to economic usage. All together 610–650 x 10³ hectares of Estonian mires (~ 65 percent of the total area) have been strongly affected or destroyed by human activities (6).

Photo: Raimo Pajula

Open fen area with moderate drainage impact in the northern part of the project area. Young pines establish rapidly on the previously open sedge fen.

Photo: Raimo Pajula

Degraded and forested fen communities with strong drainage impact in the south-eastern part of the project area. Drainage ditches are still functioning.

Picture: Raimo Pajula

Land cover map with tree height classes shows that afforestation started on the most heavily drained ditch banks and expanded towards areas with open fen vegetation. Also, availability of nutrients accelerated (meiotrophication) by drainage, which supports vegetation change – precipitation-fed vegetation and woodlands replaced earlier groundwater-fed fen vegetation. The height of trees (Betula pubescens, Picea abies, Pinus sylvestris) is mainly about 12-17 meters, partly up to 20-25 meters

Aerial photograph: Estonian Land Board, 2014

Aerial photograph of central part of the project area, prior to the restoration measures. Large old ditches caused strong drainage and resulted in degradation and forestation of mire communities.

Peatlands & Greenhouse gas emissions

Nowadays about 70 percent of Estonian mires are directly or indirectly affected by degradation. About 5000 hectares are abandoned peat mining areas, on 11,000 hectares peat mining is still being in progress (2).

Today about 70 percent of the mires are impacted by drainage, thereof 84 percent of fens and 64 percent of transitional mires. The annual CO2 emissions of Estonian mires are 7.7 megatons CO2 (1 Mt = 1 Mio. t) in which

  • 1.5 megatons derive from bogs,
  • 1.2 megatons from transitional mires and
  • 4.8 megatons from fens (2).

If the CO2 emissions from degraded peatlands are focussed, Estonia is with 2.11 tons behind Indonesia on rank 2 at the global scale (3).


  • Mati Ilomets

    National Coordinator and ecology expert Mati Ilomets has extensive knowledge of telmatology, his work has always been related to mires.
  • Laimdota Truus

    Habitat expert and PR expert Laimdota Truus is plant ecologist with long practice in fieldwork, also an editor of a popular orchid protection journal.
  • Kairi Sepp

    Field and lab assistant Kairi Sepp has experienced in bryophyte ecology and participated in mire vegetation monitoring and inventories.
  • Raimo Pajula

    Remote sensing expert and peat expert Raimo Pajula has long experience in peat composition identification and map analyses.
  • Anna-Helena Purre

    Anna-Helena Purre is a Ph.D. student and specialist in the greenhouse gas emission study.
  • Elve Lode

    Elve Lode is a hydrologist specialized in the mire hydrology.
  • Martin Küttim

    Martin Küttim is a plant ecologist, whos research is currently addressed to the phenology of peatland vegetation and the effect of climate change on peatland ecosystems.
  • Galina Kapanen

    Galina is a researcher of the water bodies, who has had a great deal of laboratory experience, especially in geochemistry and lithology of sediments investigation, both indoors and in the field. She likes analyzing relations between different things and areas, for example past and present ecosystem processes; last years actively deals with...

Partner & Co-Financer

The University of Tallinn has six different schools, with more than 10,000 students enrolled. The Institute of Ecology is part of the School of Natural Sciences and Health. A focus of the work lies on the function and the mass flow in wetland ecosystems. The employees develop research methods and scientific principles for restoring these ecosystems.

The Environmental Investment Centre is the Estonian Co-Financer of the LIFE project.


  1. Paal, J. & Leibak, E. (2011): Estonian Mires: Inventory of habitats. Publication of the project “Estonian mires inventory completion for maintaining biodiversity”. Tartu.
  2. Barthelmes, A., Couwenberg, J., Risager, M. Tegetmeyer, C. & Joosten, H. (2015): Peatlands and Climate in a Ramsar context. A Nordic-Baltic Perspective. Copenhagen.
  3. Joosten, H. (2011): The global peatland CO2 picture. In: Tanneberger, F. & Wichtmann, W. (2011): Carbon credits from peatland rewetting. Climate – biodiversity – land use. Science, policy, implementation and recommendations of a pilot project in Belarus. Stuttgart. pp. 20-30.
  4. Valk, U. (1988): Utilization of peatlands in Estonia: a historical review. Proc. 8th Int.
  5. Peat Congress, Sect. 1, Leningrad. pp. 78–82.
  1. Ilomets, M. (2015): Estonia. In: Joosten H., Tanneberger F. & Moen, A. (eds.): Mires and peatlands of Europe: Status, distribution, and nature conservation. Schweizerbart Science Publishers. Stuttgart.
  2. Kask, M. (1965) – Каск, М. (1965) Растительность болота Авасте в западной Эстонии. [Vegetation of the Avaste mire in West Estonia] Tartu: Akademiya Nauk Estonskoy SSR.
  3. Pikk, J. (1997): Metsaparanduse tulemused turvasmuldadel. [Results of forest drainage on peat soils] Akadeemilise Metsaseltsi Toimetised, IX. S. 12-16.
  4. Ratt, A. (1985): Mõnda maaviljeluse arengust Eestis läbi aegade. [About the development of land cultivation in Estonia over centuries] Tallinn: Valgus.