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 measured on 72 sample trees. D.b.h. was also measured on all trees within 3 m of each sample tree. Differences in physical characteristics between damaged and undamaged trees were assessed by discriminant and logit analysis. Damage class was best predicted by clear bole height and surrounding stand density, expressed as number of stems ha −1 . The predictive ability of the discriminant model was improved by the inclusion of relative sample tree basal area. The results of the simulated thinnings suggested that wind and snow damage could be reduced by up to 40 per cent if high-risk trees were removed when thinning.