ASSESSING THE RISK OF SNOW AND WIND DAMAGE FROM TREE PHYSICAL CHARACTERISTICS

The study was carried out in a Scots pine (Pinus sylvestris L.) stand in northern Sweden. The stand was heavily damaged by wind and snow in the 1989-1991 period. Height, clear bole height, and d.b.h. were measu red on 72 sample trees. D.b.h. was also measured on all trees within 3 m of each sample tree. Differences in physical characteristics betwee n damaged and undamaged trees were assessed by discriminant and logit analysis. Damage class was best predicted by clear bole height and sur rounding stand density, expressed as number of stems ha-1. The predict ive ability of the discriminant model was improved by the inclusion of relative sample tree basal area. The results of the simulated thinnin gs suggested that wind and snow damage could be reduced by up to 40 pe r cent if high-risk trees were removed when thinning.