Isojärvi Environmentally Valuable Forest

The Environmentally Valuable Forest (a specific land-use category) is situated in Central Finland near Jämsä. It contains 689 hectares of forest land. The stand age class structure is typical for managed forests in the region - with one substantial divergence: regeneration cuttings have not been conducted for 10 years. Consequently, the proportion of young stands is small. Most of the stands are middle-aged (28 % early middle age, 47 % late middle age).

Sites are generally rather fertile in the forest. 58 % are assigned to the Myrtillus type (submesic) and 12 % to the Oxalis-Myrtillus Type (mesic). Norway spruce is the dominant species on 40 % and Scots pine on 44 % of the area. Stands with a mixture of species are characteristic.

Topographically the area is rather diverse with hills, rocky outcrops and small patches of peatland intermingling with numerous lakes. Major lakes (Pitkäjärvi, Nuorajärvi, Saaresjärvi and Särkijärvi) break up the area into smaller blocks. The forest has been in commercial use for a long time, and management has thoroughly modified the stand characteristics throughout the forest. Peatlands have been drained with few exceptions.

The bird fauna in forests and wetlands of Isojärvi is rich. The most common breeding species are Willow Warbler, Chaffinch, Siskin, Robin, Tree Pipit, Fieldfare, Redwing, Song Thrush and Spotted Flycatcher. The area also hosts populations of Lesser Black-backed Gull and Chiffchaff that both are nationally vulnerable. Other noteworthy or near threatened species in the area include Red-throated and Arctic Loon, Honey Buzzard, Osprey, Black Grouse, Capercaillie and Cuckoo. Additionally, some species listed in the EU Bird Directive also occur there, such as Hazel Grouse, Crane and Black Woodpecker. Species associated with old-growth forests and occurring in Isojärvi area include Mistle Thrush, Treecreeper and Crested Tit.

Flying squirrels occur in the lush spruce-dominated forests of Isojärvi in at least three locations. Considering other taxa, the rare polypore Phellinus populicola occurs in at least one site. Moreover, Alpine Currant Ribes alpinum and Hedge Woundwort Stachys sylvatica that both require specific grove conditions can be found in the area.