Old-growth forest

An old-growth forest (also called primary forest, virgin forest, primeval forest, late seral forest, or in Britain, ancient woodland) is a forest that has reached a great age without much disturbance.
It has unique ecological features, and might be classified as a climax community. Old-growth features include various tree-related structures. These provide wildlife habitats which increase the bio-diversity of the forested ecosystem.
Usually old-growth forests have multi-layered, open canopies. The interwoven canopy often blocks sunlight from reaching lower trees or the forest floor. The old forests also include varied tree heights and diameters, with large fallen logs (or tree trunks) across the forest floor. In Europe, less than 7% of forests are old-growth, as mainly due to industrial logging in the 20th century. In the United States, estimates are that only 10% of old-growth forests remain. In Asia old-growth forests are sometimes lost in regional conflicts.