An old-growth forest — also termed primary forest or late seral forest — is a forest that has attained great age without significant disturbance and thereby exhibits unique ecological features and might be classified as a climax community.[1] Old-growth features include diverse tree-related structures that provide diverse wildlife habitat that increases the biodiversity of the forested ecosystem. The concept of diverse tree structure includes multi-layered canopies and canopy gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debris.