Management and biodiversity in Fennoscandian timberline forests

Northern forests grow slowly, and many of the species and ecological relationships found in them take time to develop. In Fennoscandia, economic pressures have pushed the logging industry northward into the timberline forests. The impacts of this expansion are extensive and long-lasting, but new management approaches may help.

In Finland, for example, 41% of all threatened species are rare because of forestry operations. Loss of habitats and fragmentation of forests together with hunting have caused declines in the number of large predators. Species requiring old-growth coniferous forests, such as Siberian tit, Siberian jay, and capercaillie, have declined in number as the area of virgin forest has shrunk.

Intensive forestry has changed the forest structure in many ways:

  • Tree species composition has changed, because coniferous trees are favored over broadleaf trees in forest regeneration. Many invertebrate species, such as butterflies, moths, and beetles, that live on deciduous trees have declined.
  • As a result of suppressing forest fires, pyrophilous (firedependent) species have become rare.
  • Plowing of soil and ditch digging have increased the leaching of nutrients from soil and increased humus in waters.
  • More silt has accumulated on river and lake bottoms, destroying the spawning areas of fish species. Salmonids, which are especially sensitive to changes in water quality, have been the first to disappear.

A decrease in the amount of decaying wood or coarse woody debris is another of the impacts of intensive forestry. A large number of invertebrates and lower plants such as mosses, lichens, and wood-decomposing fungi have declined in number or become threatened. These species play an important role in the decomposition of woody material. Many of these species require large-diameter logs to live on, and cannot survive on the small branches left after logging.

New forest management guidelines in many Fennoscandian countries attempt to address these problems. These methods include:

  • Smaller regeneration areas and favoring of natural regeneration whenever possible
  • Protective measures for wetlands and freshwater systems
  • Forestry management at the landscape level.

Landscape ecological management planning, or LEMP, takes into account larger units than single stands, and considers the balance between cut and uncut stands as well as connections with other areas. Under this approach, areas of special ecological significance are left untouched, such as key biotopes with specific species compositions, corridors that allow movements of animals between uncut stands and protection zones around waters and other sensitive areas. Dead and living trees are also left in logged areas to maintain species that depend on decaying wood.

Anna-Liisa Sippola, Arctic Centre, Rovaniemi, Finland. From CAFF publication: Arctic Flora and Fauna