The influence of windthrow area and timber characteristics on colonization of wind-felled spruces by Ips typographus (L.)

In the first summer (2002) after the wind-felling 71% of studied windthrow areas were colonized by I. typographus. Only 1 of the 19 areas not colonized in 2002 was colonized in 2003. The number and mean diameter of wind-felled spruces and the basal area of recently dead standing spruces were the most important windthrow characteristics influencing colonization. The models showed that an increase in these characteristics also increased the values of the response variables. This study shows that local population levels of I. typographus varied greatly within the study area (appox. 200 km × 200 km) and that this variation should be included in models predicting the colonization risks of windthrown areas.