Tundra can only exist in areas of extreme cold, limiting the countries which include it to those in the northernmost reaches of the globe. Russia, Greenland, Canada, Finland and the United States all have significant stretches of tundra. In the southern hemisphere, small patches of tundra can be found on some Antarctica islands, such as South Georgia and the Kerguelen Islands.
Aside from a few small isolated patches, tundra is confined to a belt of land that runs along the northern edge of the European and North American continents. These are some of the coldest areas on Earth, as the tundra is the coldest of the five major biomes. One of the defining features of the tundra is an almost complete lack of trees, as it is generally too cold and dry for them to grow. Plants on the tundra are limited to small shrubs, flowers and grasses that can endure the short growing season. Underneath the topsoil that allows for plant growth, the tundra has a layer of permanently frozen soil called permafrost.
Tundras share many characteristics with deserts, including low precipitation and extremely dry conditions. However, whereas deserts tend to form between the equator and the poles, the tundra is only located close to the North Pole.