The greatest extent of taiga occurs in the Northern Hemisphere because of the greater expanse of land between northern latitudes 50 degrees N and 70 degrees N as compared with the domination of ocean in equivalently located southern latitudes. The taiga forms a forest belt across North America and Eurasia, with the tundra on its northern border and the temperate forests and grasslands to the south.
Soil Features in Taiga Biome
Taiga conifer litter is highly acidic. Soils of the more humid and southern taiga are highly leached spodosols, which are characterized by the leaching of iron, aluminum, and organic matter from the chemically and biologically distinct surface layer—horizon A—to the next layer—horizon B.
Much of the soil of central and eastern Canada—granitic Canadian Shield—has been repeatedly scraped clean by glacial advances. Thus, productive forests often are restricted to portions of the landscape where soil material has been deposited by glaciers. Peaty wetlands occur where surface drainage is impeded by permafrost, youthful glacial topography, or aggraded rivers; their soils are characteristically organic soils, or histosols. Soils in much of boreal western North America and Asia are inceptisols, which have little horizon development. Very thin surface salt deposits are found in the most arid portions of the taiga.
Cold soils are characteristic of taiga regions, which overlaps the zone of permafrost. Permafrost is soil or earth material that remains below 0 °C (32 °F) for at least two years. The surface, or active, layer of permafrost thaws in the warm season and freezes in the winter, but the soil below the active layer remains continuously frozen. Because the plant rooting zone is restricted to the active layer, nutrient supply is limited and secure anchoring for roots is lacking. Some trees and other plants of the taiga (especially black spruce [Picea mariana] and tamarack [Larix laricina] in North America and larches in Siberia) can grow on permafrost if the active layer is sufficiently deep, but several species are eliminated from permafrost.
Key Features of Taiga Biome
The taiga is the biome of the needleleaf forest. Living in the taiga is cold and lonely. Coldness and food shortages make things very difficult, mostly in the winter. Some of the animals in the taiga hibernate in the winter, some fly south if they can, while some just cooperate with the environment, which is very difficult.
Taiga is the Russian word for forest and is the largest biome in the world. It stretches over Eurasia and North America. The taiga is located near the top of the world, just below the tundra biome. The winters in the taiga are very cold with only snowfall. The summers are warm, rainy, and humid. A lot of coniferous trees grow in the taiga. The taiga is also known as the boreal forest.
The taiga doesn’t have as many plant and animal species as the tropical or the deciduous forest biomes. It does have millions of insects in the summertime. Birds migrate there every year to nest and feed.
The average temperature is below freezing for six months out of the year. The winter temperature range is -54 to -1° C (-65 to 30° F). The winters, as you can see, are really cold, with lots of snow. Temperature range in the summer gets as low as -7° C (20° F). The high in summer can be 21° C (70° F). The summers are mostly warm, rainy and humid. They are also very short with about 50 to 100 frost free days. The total precipitation in a year is 30 – 85 cm (12 – 33 in) . The forms the precipitation comes in are rain, snow and dew. Most of the precipitation in the taiga falls as rain in the summer.
The main seasons in the taiga are winter and summer. The spring and autumn are so short, you hardly know they exist. It is either hot and humid or very cold in the taiga. There are not a lot of species of plants in the taiga because of the harsh conditions. Not many plants can survive the extreme cold of the taiga winter. There are some lichens and mosses, but most plants are coniferous trees like pine, white spruce, hemlock and douglas fir.
Coniferous trees are also known as evergreens. They have long, thin waxy needles. The wax gives them some protection from freezing temperatures and from drying out. Evergreens don’t loose their leaves in the winter like deciduous trees. They keep their needles all year long. This is so they can start photosynthesis as soon as the weather gets warm. The dark color of evergreen needles allows them to absorb heat from the sun and also helps them start photosynthesis early. Evergreens in the taiga tend to be thin and grow close together. This gives them protection from the cold and wind. Evergreens also are usually shaped like an upside down cone to protects the branches from breaking under the weight of all that snow. The snow slides right off the slanted branches.
The taiga is susceptible to many wildfires. Trees have adapted by growing thick bark. The fires will burn away the upper canopy of the trees and let sunlight reach the ground. New plants will grow and provide food for animals that once could not live there because there were only evergreen trees.
Animals of the taiga tend to be predators like the lynx and members of the weasel family like wolverines, bobcat, minks and ermine. They hunt herbivores like snowshoe rabbits, red squirrels and voles. Red deer, elk, and moose can be found in regions of the taiga where more deciduous trees grow. Many insect eating birds come to the taiga to breed. They leave when the breeding season is over. Seed eaters like finches and sparrows, and omnivorous birds like crows stay all year long.
Economically, the taiga forests are very important. They provide the raw materials for forestry industries in Canada, the US, Scandinavia, and Russia and are the source of considerable wealth generation. The major products are roundwood, sawnwood and pulp for paper making. Canada is the leading producer of wood products from its forests.
However, much forest exploitation is unsustainable, especially where large tracts of land are left treeless by clear felling. The situation is particularly serious in eastern Siberian forests, which are diminishing rapidly. The plight of the taiga rarely achieves the publicity attention or media interest garnered by tropical Rainforests.
Wildfire activity in the boreal forest biome, which is also known as taiga, plays a crucial role in the globe’s carbon budget, since these forests represent nearly 10 percent of the planet’s land surface and contain more than 30 percent of the carbon that is stored on land, in plants and soils. Globally, the boreal forest covers 6.41 million square miles, forming a ring along and just below the Arctic Circle.
Increased burning in recent years has meant that more stored carbon has been freed from these ecosystems, which acts as a feedback, leading to more global warming, and hence more wildfires. In addition, the black carbon, or soot, emitted from the fires can land on snow and ice in the Arctic, hastening melting.
Alaska has seen a significant increase in wildfire activity in recent years, which has been linked to the effects of a warming climate, including warmer, drier summers with greater thunderstorm activity. The new study found that while global warming is likely to lead to even greater wildfire activity in the coming decades, vegetation changes as a result of such fires may keep a lid on the magnitude of the surge in wildfire activity, as apparently occurred during the so-called “Medieval Warm Period” between about 800 to 1400 AD.
The researchers found that recent wildfire activity exceeded the range of natural variability during the past 10,000 years, which they attributed to climatic warming during the past few decades and “the legacy effect” of the Little Ice Age, which occurred from about 1350 to 1850 AD, and brought cold and wet conditions to Alaska that encouraged the growth of trees and plants in the boreal forests. Such vegetation is now serving as fuel for wildfires. Most climate projections show that wildfire frequency, size, and severity are likely to increase as the northern climate becomes warmer and drier than it is today. Studies show that there may be a fivefold increase in annual area burned during the 21st century in Alaska and Western Canada, for example. Already, the boreal forest biome has seen some of the most rapid and largest amount of warming of anywhere on earth, with a significant decline in the number of days with extremely cold temperatures, and increases in summertime overnight low temperatures and the length of the frost-free season.