old growth

A forest that has reached an advanced age without catastrophic disturbance or harvest — typically 200 years or more, though the definition varies by region and forest type. Old-growth forests are characterized by large, old trees, a multi-layered canopy, abundant standing dead trees (snags), fallen logs, and a deep, complex accumulation of organic debris on the forest floor. They are not static — they are dynamic systems in which individual trees die and are replaced, gaps open and close, and the forest continuously remakes itself. Old growth is not the absence of change; it is the presence of time.