Unspoilt old-growth forests are few and far between in most parts of Europe today. Even in Finland most forests have been exploited for their timber at some time in the past, especially in the south.
True old-growth forests can be recognised by their mixture of trees of different species and ages, and by the abundance of dead and decaying wood. These ecologically valuable features provide habitat for many mosses, lichens and fungi - and also attract many rare insects, woodpeckers, owls, capercaillies, and other birds that cannot thrive in more uniform commercially managed forests.
Many older forests are also home to the endangered flying squirrel (Pteromys volans).
Many of Finland's national parks feature extensive remnants of old-growth forest, including Seitseminen, Pyhä-Häkki and Syöte.