Vindfällning i naturliga och skapade bryn och kanter

Abstract: The aim of this work was to study if the edge of the forest is more resistant to heavy winds than the trees located further in from the edge, and how this edge effect changes between different types of tree species and site types. The data was collected from an electric power line going from the north to the south of Sweden. The mean value of the clearcutted area around the power line was 120 meters. The main direction of the storm in January 2005 was west-southwest and thus the power line was a perfect place for gathering a large data set. The main parameter studied was the damage frequency at the edge of the forest compared to the trees located further in from the edge (up to 100 m from the power line). Tree species mixture, soil moisture class, soil type, topography, stand height, stand height of the stand on the other side of the power line and wind exposition was estimated. The results showed a distinct edge effect. The edge of the forest had clearly lower damage frequency for all tree species. A marked difference was observed between tree species and damage frequency. The spruce stands was most severely damaged followed by pine stands, mixed spruce and pine stands, broadleaved stands and noble broadleaved stands. Among other parameters studied, the height of the trees was found to be very important for the damage frequency. Higher trees were more severely damaged by heavy winds, both at the edge and at the inner zone of the forest.