Old-Growth Forests

Old-growth forests are natural ecosystems dominated by large, old trees, usually of a mixed species composition, and with all ages present in the community. Old-growth forests also contain many scattered, dead trees, both standing and lying on the forest floor. In the tropics, these forests are threatened by conversion to agriculture and by other disturbances, while old-growth forests in the temperate zones are mostly threatened by forestry. Losses of these old-growth ecosystems are the most important of the modern threats to biodiversity because of the extinctions that are caused. The special values of old-growth forests are best preserved through the designation of large, landscape-scale, protected areas.