The subalpine zone is the biotic zone immediately below tree line around the world. Species that occur in this zone depend on the location of the zone on the Earth, for example, Snow Gum in Australia, or Subalpine Larch, Mountain Hemlock and Subalpine Fir in western North America.

Trees in the subalpine zone often become krummholz, that is, crooked wood, stunted and twisted in form. At treeline, tree seedlings may germinate on the lee side of rocks and grow only as high as the rock provides wind protection. Further growth is more horizontal than vertical, and additional rooting may occur where branches contact the soil. Snow cover may protect krummholz trees during the winter, but branches higher than wind-shelters or snow cover are usually destroyed. Well-established krummholz trees may be several hundred to a thousand years old.

Montane grasslands and shrublands may be found in the subalpine zone. Tuolumne Meadows in the Sierra Nevada of California, USA, is an example of a subalpine meadow.