Analysis of the November 7, 1994, windthrow in the regions of Charlevoix and Gaspesie (Quebec, Canada)

This paper examines the factors involved in important windthrows that occured in November 1994 in two regions of Quebec. Windthrown areas were mapped from aerial photos. The storm was reconstituted at different scales by using the MC2 model developed by Environment Canada and results were overlayed with windthrow mapping and forest-ecological maps. Logistic regression was used for the main combinations of variables to test the effect of wind speed, surface deposit, stand type and age. No effect of wind speed could be demonstrated. However, the damage level increased with increasing stand proportion of balsam fir in Charlevoix and with age of balsam fir stands in both regions. Damage also increased when surface deposits restricted rooting depth in the Gaspe peninsula. Much of the damage in both regions appears to be linked with an abundance of mature and overmature stands.