treeline
Treeline is the upper elevational or northernmost limit at which trees can maintain a self-sustaining population. It marks the transition between forest and treeless tundra or alpine ecosystems, and its position is not a fixed line but a zone that varies with climate, species, geography, and land-use history. In mountain regions the treeline ascends with latitude and descends with increasing aridity and wind exposure, while in polar regions it lies near the limit of suitable growing-season warmth.
The primary controls on treeline position are climate and soil. Growing-season warmth, particularly the length and
Treelines occur worldwide, including latitudinal treelines near high latitudes and altitudinal treelines on mountains. The term
Climate change is affecting treelines in many regions, with observed and projected shifts poleward or upward