Epsilon Archive for Student Projects

Abstract

Forestry and forest products are vital components of the Swedish economy but the forest is also important for recreation, hunting, out-door life and conserving biodiversity. The Swedish Forest Act has two equally important objectives, production and environmental protection. Polytax is the Swedish Forest Agency´s inventory programme which monitors progress toward the two objectives in connection with regeneration fellings. It includes data on environmental protection measures taken in connection with regeneration fellings. 30 § of the Swedish Forestry Act and related regulations specify the demands for conserva-tion of nature. Modern forestry creates monocultures and to counteract that Swedish fore-stry has introduced a number of biodiversity-orientated management practices. One of them is Green-tree retention cutting (GTR) which is a modification of traditional clear-cutting and implies that some living trees are left on the cut area.

The Swedish model of forestry builds on three different levels of conservation, general conservation consideration in all forest operations, voluntarily protected areas and site pro-tection. The purpose of the general conservation consideration is to pay attention to natural and historical environments and social values. It is based on § 30 of the Swedish Forestry Act. One category of the general conservation is nature trees, which is trees that have an obvious nature- or culture-value. The category involves living trees, dead trees, logs and natural or created snags. Nature trees are supposed to function as “lifeboats” for species and processes during the regeneration phase. The density of nature trees in mature forests reflects the management history during the last 80-100 years. For the formulation of guide-lines and requirements for tree retention it is important to be aware of changes in this den-sity, because it affects both the conservation possibilities and the conservation value of tree retention.

The first purpose of this study is to evaluate how the density of nature trees varies over time (1999-2009). The second purpose is to see how much consideration has been given to these trees at regeneration felling during the same time period.

The results show that it is a significant difference between the first five year-period and the last five years. The average number of nature trees before regenerations felling was 2,97 (1999-2003) and 2,33 (2005-2009). The degree of complete taken consideration dur-ing regeneration felling was high during the whole period with about 60 %.