In physical geography, tundra can be defined as a kind of biome in which cooler temperatures and short growing seasons lead to hindrance in the growth of trees.
Dwarf shrubs, mosses, sedges and grasses, and lichens are composed of tundra vegetation. In some regions of tundra, the growth of scattered trees is observed. The ecotone (or ecological boundary region) is referred to as the timberline or tree line and is present in between the tundra and the forest. Further, the tundra soil is found to be highly rich in phosphorus and nitrogen. There exist three regions and associated kinds of tundra, namely, Arctic tundra, alpine tundra, and Antarctic tundra.
The Arctic tundra is found in the Arctic regions of the northern hemisphere, located north to the subarctic boreal forest. The term "tundra" commonly applies to the regions whereby permanently frozen soil or permafrost is the subsoil. (In general, it can also apply to the barren plain, wherein it might include northern Sapmi.) Permafrost tundra covers large areas of Canada and northern Russia. Many groups are mainly nomadic reindeer herders throughout the polar tundra, including the Nganasan and Nenets in the permafrost zone.
There are regions of solid landscape in the Arctic tundra where it is frozen for most of the year. From 25 to 90 cm (10 to 35 in) down there, the soil is frozen, making it difficult for trees to grow. Rather, only certain forms of Arctic vegetation, low-growing plants including the heath (varieties of Ericaceae including certain crowberry and black bearberry), moss, and lichen, can withstand bare and often rocky ground.
In the polar tundra zones, there have been two primary seasons, summer and winter. It is quite cold and dark throughout the winter, with a mean temperature at about -28° C (-18° F), often dipping as low as -50° C (-58° F). Severe winter temperatures on the tundra, however, do not fall as deep as those encountered further south in the taiga areas.
Temperature goes up somewhat during summers, and the upper layers of seasonally-frozen soil disappear due to melting. This leaves the earth very moist and soggy. During the warmer seasons, the tundra is covered in marshes, wetlands, bogs and streams. During the season of summers, daytime temperatures usually rise to approximately 12° C (54° F), but may sometimes drop to 3° C (37° F) or maybe even below zero.
Antarctic tundra is found to happen on the Antarctic as well as in the subantarctic islands. These islands may include South Georgia and the Kerguelen Islands and the South Sandwich Islands. Much of Antarctica is highly cold yet dry for supporting the vegetation. Moreover, the polar tundra covers much of the continent there.
Some parts of the globe, however, specifically the Antarctic Peninsula, carries the areas of rocky soil which is highly preferable and supportive for the life of plants. Actually, the flora comprises almost 25 liverworts, 100 mosses, 300-400 lichens, and approximately 700 species of aquatic and terrestrial algae that live in uncovered rock and soil regions along the continent's coast.
In the western and northern parts of the Antarctic Peninsula, Antarctica carries two different kinds of flowering plant plants, namely, the Antarctic pearl (Colobanthus quitensis) and the Antarctic hair grass (Deschampsia antarctica). The Antarctic tundra, in comparison to the Arctic tundra, lacks a large mammal fauna. And this is mainly because of the physical isolation from the other major continents.
Since the weather and soils at higher elevations obstruct tree growth, alpine tundra does not carry trees. The alpine tundra's cold climate or snowy tundra is characterised by reduced temperatures throughout the air and is close to that of the polar climate. Alpine tundra is distinct from arctic tundra such that there is normally no permafrost seen in alpine tundra, however, alpine soils are usually better drained than arctic soils.
Stunted forests growing at the forest-tundra ecotone (the treeline) are recognized as Krummholz. Alpine tundra converts to subalpine forests below the tree line.
Alpine tundra tends to occur in mountains worldwide. The plants growing close to the ground, like sedges, perennial grasses, cushion plants, forbes, mosses, and lichens, define the flora of the alpine tundra.
The tundra forest or flora is suited to the alpine environment's harsh and unfavourable conditions, including dryness, snowy tundra, ultraviolet radiation and a limited growing season.
Fun Facts about Tundra World
In summer seasons, polar bears travel to the tundra to have their infants.
In tundra, Animals appear to have short ears and tails. In the cold, this allows them to drain little heat. They also appear to have big feet, so they can climb on top of the snow.
During the winter seasons, Lemmings, small mammals of the tundra world, burrow underneath the ice to eat grass and moss.
The term tundra comes from the word tunturi in Finnish, meaning treeless plain or barren ground.