Tundra is a polar desert, with low rainfall and precipitation.
There are two main types, arctic tundra and alpine tundra. The northernmost limits of plant growth occur in the arctic tundra, limited to shrubby or matlike vegetation. This area encircles the North Pole and extends to the taiga to the south. Alpine tundra is found high on mountains above the altitudes that trees can grow.
Decomposition takes place slowly, because of the low temperatures. The ground is frozen year-round, known as permafrost. The winters are long and cold, and there is a short growing season, of less than 60 days. There is an annual 0 to 24 hour change in day length - there is constant darkness in the winter, and constant sunlight during the summer.
Plant life consists of low shrubs, sedges, grasses, mosses and lichens, with special adaptations. Because of the very low temperatures they are slow to recover from disturbances. Plant growth and reproduction occur in a very short period of time during the brief summer.
There is a low diversity of animals in the tundra. Blackflies, deerflies and mosquitoes are abundant during the short summer. Herbivores include caribou, musk ox, polar bears, and birds.