Predisposition assessment of mountainous forests to bark peeling by red deer (Cervus elaphus L.) as a strategy in preventive forest habitat management.

A method to assess the predisposition of mountainous forests to bark peeling by red deer (Cervus elaphus) is presented. It illustrates options in preventive forest habitat management to reduce the risk of bark peeling damage. This Predisposition Assessment System (PAS) is developed as an expert system, based on expert interviews and literature analyses. We selected the most important site- and stand-related predisposing factors for bark peeling of red deer, considering the relation of food dependent and food independent settling stimuli. The mechanistic expert system works as an award-penalty point system. The verification of the system was taken with data of the Limestone Alps National Park (Upper Austria). Three site-related indicators, i.e. terrain features, roughness/smoothness of relief, and local climate, and six stand-related indicator, i.e. tree age, canopy cover, proportion of conifers, cover of herb layer, method of final cutting, and harassment, were included in the verification. Both the chosen indicators and the overall assessment clearly reflected the predisposition in terms of relative frequencies of peeled and unpeeled sample plots. A supplemental logistic regression run with the occurrence/absence of bark peeling as response variable and the assessed predisposition scores from the PAS as explanatory variable proved the discriminatory value of the PAS.