Det svenska trakthyggesbrukets miljöpåverkan - En litteraturstudie med fokus på biologisk mångfald
Sammanfattning: 80% of all forest in Sweden is considered to be in active use and since the mid 20th century, clear-cutting is the dominating forestry management method. The implication of clear-cutting is that large areas (up to 200 hectare) are being harvested at once and leaving bare ground as a result. The purpose of this master’s thesis was to compile the current knowledge about the effect of clear-cutting on biodiversity and more specifically the species groups vascular plants, cryptogams, beetles and birds. The thesis was performed as a qualitative literature review and the result shows that clear-cutting can affect the biodiversity in both positive and negative ways, depending on what species or species group being focused on. Species holding a limited ability to disperse is negatively affected by a clear-cut, e.g. the orchid fairy slipper (Calypso bulbosa), tree lungwort (Lobaria pulmonaria) and the lucanid beetle Ceruchus chrysomelinus. On the other hand, species thriving in sunny environments and not being sensitive to disturbances is positively affected by a clear-cut, e.g. wavy hair grass (Deschampsia flexuosa), raspberry (Rubus idaeus) and meadow pipit (Anthus pratensis). Many species are dependent on forests with long continuity and high amounts of dead wood. Those structures are often found in natural forests and not in the managed monocultures. Therefore, it is of great importance to protect and retain the remaining natural forests. Leaving retention trees and high stumps on clear-cuts is one way of reducing the negative effects of clear-cutting and it could create suitable habitats for many species. However, this practice is relatively new in Sweden and more long term studies are needed to evaluate whether the practice is enough to maintain the biodiversity alongside forestry dominated by clear-cutting.
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