In physical geography, tundra is a type of biome where tree growth is hindered by frigid temperatures and short growing seasons. The term is a Russian word adapted from Sámi languages. There are three regions and associated types of tundra: Arctic tundra, alpine tundra, and Antarctic tundra.

Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation, with an associated harsh climate. As the latitude of a location approaches the poles, the threshold elevation for alpine tundra gets lower until it reaches sea level, and alpine tundra merges with polar tundra.