Modelling the risk of snow damage to forests under short-term snow loading

• Published in: Forest ecology and management 1999-04, Vol.116 (1), p.51-70
• Main Authors: Päätalo, Marja-Leena, Peltola, Heli, Kellomäki, Seppo
• Format: Article
• Language: English
• Subjects: Betula; Biological and medical sciences; biological resistance; Birch; Critical snow load; Critical windspeed; diameter; forest borders; forest management; Fundamental and applied biological sciences. Psychology; height; mathematical models; Mechanistic wind and snow damage model; Norway spruce; Phytopathology. Animal pests. Plant and forest protection; Picea abies; Pinus sylvestris; plant characteristics; Regression models; Risk assessment; risk reduction; Scots pine; simulation models; snow; snow cover; snow damage; species differences; stand density; Stand management; Stem breakage; thinning; Uprooting; Weather damages; Weather damages. Fires; wind damage; wind speed
• ISSN: 0378-1127; 1872-7042
• DOI: 10.1016/S0378-1127(98)00446-0

Regression models are developed to assess the risk of snow damage to Scots pine ( Pinus sylvestris L.), Norway spruce ( Picea abies (L.) Karst) and birch ( Betula spp.) stands based on simulated data, employing a mechanistic wind and snow damage model developed by Peltola et al., 1998a. The risk is predicted in terms of the critical windspeed needed to cause stem breakage and uprooting of trees at forest edges under short-term snow loading. Separate regression models are developed for each tree species using stem taper (breast height diameter of stem relative to tree height, d 1.3/ h), stand density, snow loading and distance from the stand edge as variables, and a general model for stem breakage and uprooting is also proposed having tree species as an additional dummy variable. The overall risk of stem breakage and uprooting is shown to increase with snow loading and decrease with increasing stem taper and stand density for all three tree species, although Scots pines and Norway spruces are predicted to be much more susceptible to snow damage than birches, which, being leafless, had much less crown area for snow attachment and wind loading. The greatest susceptibility to stem breakage and uprooting is seen at the stand edge, where the risk due to wind loading is much greater than inside the stand. Under these circumstances, slightly tapering Scots pines and Norway spruces are found to be the most vulnerable under a snow load of 60 kg m −2, suffering damage at windspeeds of