Human Transformations of the Swedish Boreal Forestry

A successful production-oriented forestry has influenced nearly all Swedish boreal forests. Accordingly, the standing volume has increased continuously since official data became available in the 1920s. On the other hand, there is very little natural forest left, except in the sub-alpine area. In the pre-industrial era, probably the most important human impact on the Swedish boreal forests (around two-thirds of the country's productive forest land may be considered as boreal) was the conversion of forests to arable land, e.g. on sediments around lakes and in river valleys. In the 19th century, fire suppression had become effective in the whole area. Until the beginning of the present century, the iron industry in the southern part of boreal Sweden needed large quantities of wood and charcoal. To ensure this supply, forest management based on the clear-felling harvest system was introduced in the middle of the 19th century. Today, most sites in this region carry their second or third rotation. North of the mining district, i.e. the major part of boreal Sweden, a logging frontier moved northwards during the 19th century. Initially, large diameter Scots pine was cut in a purely exploitive manner. The standing volume was substantially reduced, probably from a level higher than today's. This selective cutting was replaced by the clear-felling system around 1950, when the state launched a restoration program to regenerate low-stocked sites. Since 1950, around 44% of the productive forest land in boreal Sweden has been cleared. Intensive regeneration measures and stand treatments have generated rather homogeneous stands dominated by conifers. Since 1970, lodgepole pine, introduced from western Canada, has been planted on 4% of the productive forest land in boreal Sweden. These radical changes in the Swedish boreal forests have heavily altered the natural processes and structures at different spatial scales. Fragments of woodland key habitats containing red-listed plants (mainly cryptogams as fungi, lichens, and mosses) and animals (mainly insects) are embedded in a matrix of well-managed forests. From a biodiversity point of view, the most important management measures probably are to increase the number and quality of undisturbed forests and the amounts of coarse woody debris and deciduous trees, and to reintroduce fire