Metsähallitus (Forest Service) decided to protect two areas around Hiisijärvi lake in Eastern Finland already in 1916. Later, a natural park was suggested to be established in the area. A survey of the vegetation in the area was composed in 1931-1932. The total land area of the protected area was 3.5 km3. A vegetation map was drawn based on a nature inventory. A detailed description of the forest site types, peatland types, aquatic flora and the vegetation of the area are included in the article. The calcareous soil promotes rich vegetation. Typical for the area are also rich fens. The area can be divided to a eutrophic and a oligotrophic part.
The PDF includes a summary in German.