Cavities are created when physical wounding of the trunk occurs whether by human, weather or wildlife action. These wounds are then expanded by wood decaying fungi, bacteria or wildlife and can occur anywhere on the tree, but are most critical when they occur in the trunk or in major stems and branches.

The purpose of this manual is to inform landowners, foresters, timber buyers, loggers, site preparation and reforestation contractors, and others involved with silvicultural operations about common-sense, economical and effective practices to minimize non-point source pollution (soil erosion and stream sedimentation) and thermal pollution. These minimum practices are called BEST MANAGEMENT PRACTICES and are commonly referred to as BMPs.