The causes of browsing, bark stripping, and fraying damage by deer are examined by reviewing the available literature. Trees species differ in vulnerability and each form of damage occurs within certain age and size classes. Stem morphology has an important influence on bark stripping; lower branches and bark thickening tend to deter stripping in any one species. Site related factors such as hiding cover, snow and soil fertility also influence damage. The data relating deer population density to damage are imprecise and there is a need for improved density estimation methods to demonstrate the benefit of culling in different habitats. Vegetation affects both habitat and diet selection in deer, and can create both positive and negative relationships with damage. Computer models are proposed as an aid to damage prediction and forest protection decision making.