How does altitude affect vegetation on mountains?

Altitude has a strong effect on mountain vegetation because as elevation increases, temperature, oxygen levels, and air pressure decrease. Near the base, warm climates support dense forests with a wide variety of trees and plants. As one climbs higher, temperatures drop and vegetation changes to coniferous forests, shrubs, and grasses adapted to cooler conditions. In the alpine zone, only hardy mosses and lichens survive, while at the highest altitudes, snow and ice prevent most plant growth. This gradual change in vegetation across different heights is called altitudinal zonation. It creates diverse ecosystems that support unique species at every mountain level.