Bark Beetles in North American ConifersBecause they prey upon a wide variety of conifers, bark beetles have a major impact upon western forests. In most of the western states, for example, we have witnessed bark beetles in epidemic outbreaks, attacking and damaging ponderosa pine, limber pine, and other hosts. The ecosystem of bark beetle and host tree is a highly coevolved community of organisms in which the evolution of one member of the community significantly influences the evolution