Factors affecting beech bark stripping by red deer (Cervus elaphus) in a mixed forest

Abstract

Bark stripping by large herbivores is widespread, yet poorly understood. Our study was carried out in a 2000-ha area situated in the Vosges Mountains, France, where beech Fagus sylvatica bark is heavily bark stripped by red deer Cervus elaphus. We tested whether the seasonal variation in the frequency of beech bark stripping by red deer was correlated with bark nutritive value or bark mechanical properties (using an index of bark detachability). We also evaluated whether red deer selected beech trees based on the chemical composition of their bark (e.g. carbohydrates and minerals). Bark-stripped trees had slightly higher carbohydrate contents than non-stripped trees, but this difference resulted from a physiological reaction of the tree to bark stripping. Bark composition was similar between stripped and non-stripped trees spring and summer, but was easier to detach during these periods than during autumn and winter. Therefore, beech bark stripping by red deer in the Vosges Mountains does not appear to be driven by nutritional needs, but it may help deer in improving digestion efficiency.