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 taxonomy. 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.
Alpine plants are not limited to higher latitudes. These areas have different ecology than those located at higher latitudes.  One of the biggest distinctions is that the lower bound of a tropical alpine area is difficult to define due to a mixture of human disturbances, dry climates, and a naturally lacking tree line.  The other major difference between tropical and arctic alpine ecology is the temperature differences. The tropics have a summer/winter cycle every day, where as the higher latitudes stay cold both day and night. In the northern latitudes, the main factor to overcome is the cold. Intense frost action processes have a profound effect on what little soil there is and the vegetation of arctic alpine regions.  Tropical alpine regions are subject to these conditions as well, but they seldom happen. Because northern alpine areas cover a massive area it can be difficult to generalize the characteristics that define the ecology.  One factor in alpine ecology is wind in an area. Wind pruning is a common sight within northern alpine regions. Along with wind pruning, wind erosion of vegetation mats is a common sight throughout Alaska.