Forests

Judging by both the total area and number of species, forests are the most important major habitat type in Finland. Forests on mineral soil cover almost 15 million hectares of land. This corresponds to 36% of the country's total area and 49% of land area. The share of species which primarily inhabit forests corresponds to 42% of all well-known species in Finland. Several forest species also occur in for example wooded mires and rocky habitats.

Herb-rich forests are the most species rich forest habitats. Almost one third of all well-known forest species inhabit herb-rich forests, even though the share of these habitats in only 1% of the total forest area. The amount of species is generally decreased in dryer and nutrient-poorer habitats. In addition to herb-rich forests, old forest are important for species diversity. Approximately 13% of all forest-species occur in these habitats. At present, almost all forests in their natural state are old forest, since few natural state forests have developed during the last decades.

What and where?

The definition of forest often varies with context. In forestry, a forest has traditionally been defined based on annual production of wood. In national forest inventory (NFI) all wooded habitats with annual growth potential of more than one cubic meter of wood per hectare were included in forests. Another generally used method is classification based on tree canopy coverage. Forests are then all areas which have for example 30% canopy coverage. According to the Food and Agriculture Organization of United Nations (FAO), forests include all areas with more than 10% canopy coverage and tree length of at least 5 meters.

From the ecological point of view, however, it is more appropriate to determine forests by their soil type and ground vegetation. In that case, forests are mineral soil sites which are able to host communities characterized by tall tree stand. According to this definition forests on peatlands are classified into mires (spruce and pine mires), and wooded sites with rock exposures into rocky habitats.

Forests dominate the Finnish landscape quite evenly in the whole country. Only in parts of the fell area in northern Lapland, the share of forests of the total area is less than 30%. Also in coastal areas and Kainuu there are a little less forests than the average. In southern and south-western Finland there are more population centers and agriculture than elsewhere. Ostrobothnia and Kainuu are instead rich in mires. The abundance of old forest in their natural state is decreasing in the whole country. Their share of all forests is less than 5%. Most natural state forests are found in Lapland, Kainuu and North Karelia.