Diversity

The main tree species occurring in Swedish forestry are spruce and pine. Birch often occurs within spruce and pine forests, and is the third most common tree species. Together, these make up about 90 percent of the trees found within the boreal forest. 

The current felling cycle in Swedish forestry is approximately 70–100 years. Some imported coniferous species occur within the nation’s forestry. Among them is the North American Contorta pine—a distinct pioneer tree species with rapid growth in its youth.

A forest is comprised by more than its trees. The biological diversity of the coniferous forest belt has developed since the ice age, but boreal forests can be considered as relatively limited in species compared to forests in tropical climates.

Biological diversity has to do with each species ability for dispersal. The life conditions of a species correlates to other species within the same ecosystem. If one species in an area is eliminated, one generation of trees is rarely enough time for that species to re-establish itself.

The biological diversity in the boreal forests of Sweden is rapidly diminishing. 50 percent of all red-listed, threatened species have their habitat in forests. Many of these species are dependent on the presence of dead wood in the forest. 

The development of forestry during the last centuries contrasts with nature's ability to self-heal and also the question whether the changes within the biological diversity are irreversible or not.