permafrost
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View of a typical tundra environment in Greenland, with a glacier visible in the background. Tundra is the name given to a region spreading across North America and Eurasia where the ground is frozen all year (permafrost). With too severe a climate for trees to grow, tundra lands support hardy vegetation such as moss and lichen, although during the brief summer many flowering plants appear when the top few centimetres of soil thaw.
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Denali National Park and Preserve in Alaska, USA. Opened in 1917 as Mount McKinley National Park (North America's highest mountain lies within its 6 million acres/2.4 million ha), this sub-arctic landscape of tundra, waterlogged ground, and permafrost was designated an International Biosphere Reserve in 1976.
Condition in which a deep layer of soil does not thaw out during the summer. Permafrost occurs under periglacial conditions. It is claimed that 26% of the world's land surface is permafrost.
Permafrost gives rise to a poorly drained form of grassland typical of northern Canada, Siberia, and Alaska known as tundra.
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