Old-growth forest
An old-growth forest is a mature forest with long ecological continuity and structures shaped by many decades or centuries of growth.
Forest succession: The sequence of changes in species composition and structure as a forest develops over time. Long periods of succession build the layered canopies and varied tree sizes found in old-growth stands.
Gap dynamics: The cycle in which a tree dies, opens a canopy gap, and allows new plants to grow. Small gaps replace individual trees while preserving much of the surrounding old forest.
Forest conservation: The protection and sustainable stewardship of forest ecosystems and their biodiversity. Conservation policy often prioritizes remaining old-growth stands because their structures take centuries to develop.
Temperate rainforest: A forest in a temperate climate with high rainfall and abundant moisture-dependent vegetation. Some temperate rainforests contain exceptionally large trees, deep moss, and extensive dead wood.
Secondary forest: A forest that regrows after a major disturbance or the removal of its previous vegetation. A secondary forest may become mature without yet having the continuity and structures of old growth.
Ecological continuity: The persistence of habitat conditions and ecological processes at a site across generations. Continuity helps distinguish old-growth forests from mature stands that followed recent clearing.
Tree mortality: The death of trees through aging, competition, disease, or environmental stress. Mortality creates snags, fallen logs, and openings that sustain varied forest structure.
Forest carbon sink: A forest that absorbs and stores more carbon than it releases over a given period. Large trees and dead wood hold substantial carbon, though storage varies with forest type and disturbance.
Białowieża Forest: A lowland forest on the Poland–Belarus border that includes some of Europe's best-preserved natural woodland. Its long-continuity stands preserve European forest structures rarely found elsewhere.
Primary forest: A forest that has not been cleared and subsequently regrown through human activity. Primary forest and old-growth forest overlap, but the terms emphasize different histories and criteria.