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Tundra vegetation is composed of dwarf shrubs, sedges, grasses, mosses, and lichens. Scattered trees grow in some tundra regions. The ecotone (or ecological boundary region) between the tundra and the forest is known as the tree line or timberline. The tundra soil is rich in nitrogen and phosphorus. [2]
The tundra is an extremely harsh, cold, windy, and unique ecosystem found on the extreme north and south latitudes of our Earth. The soil consists mostly of frozen permafrost, which makes it difficult for extended root systems to grow, and water to drain and support a wide variety of plant life.
Arctic vegetation is largely controlled by the mean temperature in July, the warmest month. Arctic vegetation occurs in the tundra climate, where trees cannot grow.Tundra climate has two boundaries: the snow line, where permanent year-round snow and ice are on the ground, and the tree line, where the climate becomes warm enough for trees to grow. [7]
The southern edge of the Canadian Arctic tundra is met by an arboreal tree line - the Arctic forest tundra transition zone. In order to adapt to the extreme conditions of the Arctic, plants have: reduced leaf size to minimize water loss to wind; fuzzy hair-like structures or alternatively grow in mats to protect themselves from snow and wind damage
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 .
Plants have several avoidance mechanisms to prevent freezing. They can build up insulation, have their stems close to the ground, use the insulation from snow cover, and supercool. When supercooling, water is able to remain in its liquid state down to −38 °C or −36 °F (compared to its usual 0 °C or 32 °F freezing point). After water ...
South Georgia supports a rich tundra with 50 species of vascular plants. The colder South Orkney and South Shetland islands support only simple mosses, lichens, and algae. The islands have no native land animals, but support a marine fauna that include sea birds and seals. [8]
Taiga trees tend to have shallow roots to take advantage of the thin soils, while many of them seasonally alter their biochemistry to make them more resistant to freezing, called "hardening". [36] The narrow conical shape of northern conifers, and their downward-drooping limbs, also help them shed snow.