Silvicultural models to maintain and restore natural stand structures in Swedish boreal forests

Almost all productive Swedish forests have been managed for timber production for a long period of time. More sensitive so-called red-listed species are today restricted to small remnant habitats in a managed landscape matrix. It has been hypothesized that natural biodiversity can be maintained if forest management mimics natural processes, blends natural structures and includes natural composition into the production forest. The most important restoration measures in Swedish boreal forests for promoting biodiversity are to increase the number and quality of undisturbed forests, the amounts of coarse woody debris, the number of deciduous trees, and to introduce fire as an ecological process. On the basis of current knowledge of natural forest dynamics, we here present management options for three major site types in boreal Sweden which mimic natural dynamics better than traditional forestry. In the natural stages, the sites carried (1) Scots pine forest, (2) deciduous or Norway spruce dominated forest, and (3) Norway spruce forest regenerated by so-called gap dynamics, respectively. The flora and fauna that characterize the first two, fire-influenced sites are considered relatively well-adapted to the kind of large-scale disturbances characterizing forestry. On these sites, therefore, the modifications proposed are within today's approach to applying the clear felling system. Sites that seldom experience fire may host species extremely sensitive to large-scale disturbances. If such sites are to be used for timber production, modified forestry practices using selection or shelterwood systems with relatively dense shelterwoods are suggested. (C) 1997 Elsevier Science B.V.