| What it is | Elevation where trees stop growing |
| Caused by | Cold, wind, short growing season |
| Above it | Open, exposed alpine terrain |
| Difficulty | Beginner concept |
Treeline (or timberline) is the elevation above which trees can no longer grow, due to cold, wind, and a short growing season. Above treeline the landscape becomes open alpine terrain — more exposed to weather, harder to navigate, and ecologically fragile — so hikers take extra care there.
What changes above it
You lose forest shelter and gain exposure to wind, sun, and lightning; navigation relies on cairns rather than blazes; and you enter the fragile alpine zone where Leave No Trace matters most.
Frequently asked questions
What is treeline?
Treeline, also called timberline, is the elevation (or latitude) above which the climate is too harsh for trees to grow. Below it you're in forest; above it the landscape opens into alpine terrain of low plants, rock, and meadow.
Why don't trees grow above treeline?
The combination of intense cold, fierce wind, a very short growing season, and thin soils prevents trees from surviving and reproducing. The exact elevation varies with latitude, aspect, and local climate.
What changes above treeline?
You lose the shelter of forest, so you're far more exposed to wind, sun, cold, and lightning; navigation gets harder without trees; and the fragile alpine vegetation demands that you stay on rock or trail. Trails above treeline are often marked with cairns.
Sources
- Alpine environments — National Park Service