Stormskador i lärk och gran : en jämförelse efter stormen Gudrun

Sammanfattning: The storm Gudrun January 8-9 2005 felled about 70 millions cubic metres forest in southern Sweden. The majority of the wind damaged forest was spruce (Picea abies). In order to decrease the risk of wind damages in the future other trees species are of interest for forestry in southern Sweden. The purpose of this master thesis was to study if larch were more wind tolerant than spruce. The method was to compare larch, Japanese larch (Larix kaempferi Lamb.), European larch (L. decidua Mill.) and hybrid larch, (L. x eurolepis A. Henry) and spruce growing side by side and with equivalent premises. Totally 26 pairs of larch and 34 stands of spruce were used. Of the larch stands 15 was hybrid larch, 9 Japanese larch and 2 European larch. This study showed that larch was damaged by wind to a smaller extent than spruce. In the larch stands 23% of basal area was felled by the storm compared to 32% for spruce. The difference was not significant. No difference in wind damages between the larch species was found, but there was a trend that hybrid larch hade more damage than Japanese larch. The relationships between wind damage and studied stand properties were generally weak. For spruce wind damage increased with increasing age and dominant height. For larch there were no such trend. Spruce had increased wind damages with increased numbers of thinning. Larch however, showed no significant relationship between wind damages and number of thinning. The local comparisons between larch and spruce showed that the selection of the material agreed with the criteria that were set up with regard to similar phase development and previously thinning. Different treatments in a thinning experiment with hybrid larch showed severe wind damage in untreated and intensively thinned stands. However, treatments with low density shelterwood stands were not damaged by the wind.