Risk factors for bark stripping damage on Norway spruce by red deer

Norway spruce Picea abies is an economically important tree species in Europe, actively managed for forestry. Among the most negative biotic factors for growth and hence forest production is damage caused by wildlife, such as damage through bark stripping by red deer Cervus elaphus . We quantified bark stripping damage on Norway spruce trees in across 450 stands (aged 20–72 years) spanning a 400 km latitudinal range along Norway's west coast and analysed the underlying mechanisms driving increased probability of bark stripping by red deer. A total of 74% of tree stands had bark stripping damage. The mean percentage of damaged trees was 16.0%, but 50 stands (11.1% of the stands) had more than 50.0% damaged trees. The most important factor determining probability for bark stripping was broad‐scale red deer density, where the probability increased markedly when density reached approximately two harvested red deer per km 2 . In addition, proximity to agricultural farmland, distance from roads, site productivity, distance between twig whorls and terrain ruggedness index increased the probability of bark stripping. Our study on bark stripping on Norway spruce highlights the importance of red deer population control, but also the importance of evaluating environmental factors as well as site factors and tree characteristics in forestry planning to mitigate damage from red deer.