Alpine plants are plants that grow in an alpine climate, which occurs at high elevation and above the tree line. Alpine plants grow together as a plant community in alpine tundra. Alpine plants are not a single taxon. Rather, many different plant species live in the alpine environment. These include perennial grasses, sedges, forbs, cushion plants, mosses, and lichens. Alpine plants must adapt to the harsh conditions of the alpine environment, which include low temperatures, dryness, ultraviolet radiation, and a short growing season.