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Ecoregion: Taiga
4/16/03 3:51 PM
Taiga
INTRODUCTION
Taigas are boreal forests, or northern coniferous forests. (Taiga is Russian for " marshy pine forest.") They stretch across the
northern parts of North America, Europe, and Asia. They are usually located south of tundra and north of temperate deciduous
forests and grasslands. Taigas also extend south in the alpine regions of the Rocky Mountains and the Sierras in the western
United States. The taiga is the largest biome on Earth. It covers about 20 million hectares (50 million acres) of land, about 17%
of Earth's land area.
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There is always abundant water in taigas,
even in areas of dense trees
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Some sections of taiga have space between conifer
trees, where grasses, wildflowers, shrubs, and
deciduous trees, such as aspens, grow.
There are two types of taiga: open woodlands with widely spaced trees, and dense forests whose floor is usually in shade.
ABIOTIC DATA
The taiga is characterized by a cold, harsh climate, low rate of precipitation (snow and rain), and short growing season. Long,
severe winters last up to 6 months, with average temperatures below freezing. Summers are short, lasting maybe 50 to 100 days
without frost.
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Winters in the taiga are long and cold.
Heavy snowfall is common.
Courtesy of Teri Dannenberg
Melting snow feeds lakes and streams and provides much of the water spring and
summer.
The taiga is very, very cold in the winter. Temperatures vary widely. For example, Verkhoyansk, Russia, has recorded extremes
of –67°C to 32°C (–90°F to 90°F). When the warmer temperatures of summer come, ice and snow melt. The hours of daylight are
much longer during the summer.
Data from Missouri Botanical Garden
Yearly rainfall in taiga is 38–85 cm (15–33 in.)
Average annual precipitation is 38 to 85 centimeters (15 to 33 inches). Most precipitation comes in the summer months.
Summers are rainy, warm, and humid. The evaporation rates are low, so the air is usually humid during the summer.
BIOTIC DATA
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Many conifer trees (evergreens with needles) grow in the taiga. These include evergreen spruce, fir, pine, and deciduous larch, or
tamarack. In North America, one or two species of fir and one or two species of spruce are dominant. Across Scandinavia and
western Russia the Scotch pine is a common inhabitant of the taiga.
Some broadleaf deciduous trees and shrubs also grow in the early development of a taiga. Most common are alder, birch, and
aspen. Scientists recognize a 200-year cycle of growth in taiga forests. The cycle goes between nitrogen-adding aspen forests
and nitrogen-using spruce-fir forests. Aspens quickly grow in newly formed meadows. They provide shelter for the slower-growing
pines. As the aspens age and begin to die, the pines take over as the dominate tree. This cycle is called forest succession.
Courtesy of U.S. Fish and Wildlife Service
The brown bear, also called grizzly bear, is one of the
largest North American land mammals.
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An aspen tree grows at the edge of a dense stand
of conifer trees. Notice the young pine trees
nearby.
Taigas are relatively low in animal diversity because of the harsh winters. They have fewer animal species than tropical or
temperate deciduous forests. Some taiga animals cope with the cold winter environment, but many migrate south to warmer
climates during the winter. Others hibernate until warmer temperatures return.
Fur-bearing predators like the lynx and members of the weasel family (e.g. wolverine, fisher, pine martin, mink, ermine, and
sable) live in taigas. They prey on herbivores like snowshoe or varying hares, red squirrels, lemmings, and voles.
Courtesy of John and Karen Hollingsworth , U.S. Fish and Wildlife Service
The gray wolf is a top predator in the taiga of North
America. Humans have moved in and eliminated wolves
as predators that threaten livestock.
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The rare Siberian tiger is found
in the taiga of northern Russia
and China. It has been hunted
for its striking fur.
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Large herbivores graze in the taiga on deciduous trees and shrubs. These herbivores include elk and moose. The beaver, the
basis for the early North American fur trade, also thrive when deciduous trees and shrubs are plentiful.
Thousands of bird species migrate to the taiga in the summer to nest. Insect eaters, like the wood warblers, migrate south after
the breeding season. Seed eaters (finches and sparrows) and omnivores (ravens) are usually year-round residents. During years
when food is scarse birds like the evening grosbeak, pine siskin, and red crossbill leave the taiga in winter and may be seen at
bird feeders as far south as Virginia.
ISSUES
One of the issues that affect the health of the taiga is human development, which reduces habitat for the plants and animals that
live there. Humans kills predators that threaten livestock. We build roads and power lines, and explore for minerals. The natural
succession of the forest is disrupted when forest fires are suppressed to protect human dwellings.
Many of the taigas of the world are what is called old growth forests. Their large trees are desirable for the lumber industry. Old
growth forests have virtually disappeared in Norway, Sweden, Finland, and Russia; few are left in North America. The removal of
all the large trees affects the natural rate of succession.
Courtesy of Joe Frobister, Taiga Rescue Network
This part of the Whiskey Jack Forest Management Area, Ontario,
has been clear-cut for many years. After this type of logging the
soil is exposed to much higher rates of erosion.
Waste products from mining and development may pollute the land and water. Industrial contaminants from around the world
have accumulated in taiga food webs. These contaminants along with naturally occurring substances, such as some metals and
radioactive material, are transported in by wind and rain.
Climate change is also an issue. Scientists continue to track and compare temperature data to determine whether it has affected
taiga. Warming temperatures can affect habitats, by melting permafrost areas, raising lake levels, and changing vegetation
growth patterns. In addition, the maximum and minimum temperatures might be higher and the precipitation patterns might
change. Worldwide, precipitation has increased in high latitude areas where the taiga is located. There is not enough data to
determine whether changes have occured.
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