Detaljhänsyn efter slutavverkning : kvantitet och inverkan på framtida produktion hos SCA i Västerbotten

Abstract: According to FSC (Forest Stewardship Council) shall at least a mean of 10 trees per hectare including riparian zones and other areas with high biological values be left in final felling. In addition large clear areas should not be created and all retained trees with high environmental value shall be spared. To leave trees in final felling means a lower cutting volume and hence a lower income from the cutting, but it also means that the production in the next generation becomes less because of competition. The aim of this study was to evaluate the effect retained trees have on the production in the new generation of forest, and to investigate if there is any way to lower this effect. The environmental care has also been estimated by the amount left in final felling. This project was done on SCAs initiative, comprised the forest administration of Västerbotten and was limited to the districts Åsele and Kusten. The project only includes trees and groups of trees left in final felling. Thirteen objects which were harvested under the year of 2003 were inventoried during the autumn of 2004. All trees and groups of trees with a commercial value were measured, and compared to SCAs instructions for environmental care in final felling. The volume measured was estimated to 3.3 m3 ha-1 of which 0.7 m3 ha-1 was judged to be above the demand according to the level that FSC require. The production loss was calculated to 1.8 % or 6.6 m3 ha-1 during a whole rotation. The possibilities to lower these losses were judged as limited.