Taiga (; rus, тайга́, p=tɐjˈɡa; relates to Mongolic and

Turkic Turkic may refer to: * anything related to the country of Turkey * Turkic languages, a language family of at least thirty-five documented languages ** Turkic alphabets (disambiguation) ** Turkish language, the most widely spoken Turkic language * ...

languages), generally referred to in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

as a boreal forest or snow forest, is a biome characterized by

coniferous Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...

forests consisting mostly of pines,

spruce A spruce is a tree of the genus ''Picea'' (), a genus of about 35 species of coniferous evergreen trees in the family Pinaceae, found in the northern temperate and boreal (taiga) regions of the Earth. ''Picea'' is the sole genus in the subfami ...

s, and larches. The taiga or boreal forest has been called the world's largest land biome. In North America, it covers most of inland Canada, Alaska, and parts of the northern contiguous United States. In Eurasia, it covers most of

Sweden Sweden, formally the Kingdom of Sweden,The United Nations Group of Experts on Geographical Names states that the country's formal name is the Kingdom of SwedenUNGEGN World Geographical Names, Sweden./ref> is a Nordic country located on ...

, Finland, much of Russia from

Karelia Karelia ( Karelian and fi, Karjala, ; rus, Каре́лия, links=y, r=Karélija, p=kɐˈrʲelʲɪjə, historically ''Korjela''; sv, Karelen), the land of the Karelian people, is an area in Northern Europe of historical significance for ...

in the west to the Pacific Ocean (including much of Siberia), much of Norway and Estonia, some of the Scottish Highlands, some lowland/coastal areas of Iceland, and areas of northern Kazakhstan, northern Mongolia, and northern

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

(on the island of

Hokkaidō is Japan's second largest island and comprises the largest and northernmost prefecture, making up its own region. The Tsugaru Strait separates Hokkaidō from Honshu; the two islands are connected by the undersea railway Seikan Tunnel. The la ...

The main tree species, depending on the length of the growing season and summer temperatures, vary across the world. The taiga of North America is mostly spruce, Scandinavian and Finnish taiga consists of a mix of

, pines and birch, Russian taiga has spruces, pines and larches depending on the region, while the

Eastern Siberian taiga The East Siberian taiga ecoregion, in the Taiga, Taiga and boreal forests biome, is a very large biogeographic region in eastern Russia. Setting This vast ecoregion is located in the heart of Siberia, stretching over 20° of latitude and 50° of ...

is a vast larch forest. Taiga in its current form is a relatively recent phenomenon, having only existed for the last 12,000 years since the beginning of the Holocene epoch, covering land that had been mammoth steppe or under the

Scandinavian Ice Sheet The Weichselian glaciation was the last glacial period and its associated glaciation in northern parts of Europe. In the Alpine region it corresponds to the Würm glaciation. It was characterized by a large ice sheet (the Fenno-Scandian ice sheet) ...

in Eurasia and under the Laurentide Ice Sheet in North America during the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of ...

. Although at high elevations taiga grades into

alpine tundra Alpine tundra is a type of natural region or biome that does not contain trees because it is at high elevation, with an associated alpine climate, harsh climate. As the latitude of a location approaches the poles, the threshold elevation for alp ...

through Krummholz, it is not exclusively an alpine biome, and unlike subalpine forest, much of taiga is lowlands. The term "taiga" is not used consistently by all cultures. In the English language, "boreal forest" is used in the United States and Canada in referring to more southerly regions, while "taiga" is used to describe the more northern, barren areas approaching the tree line and the tundra. Hoffman (1958) discusses the origin of this differential use in North America and how this differentiation distorts established Russian usage. Climate change is a threat to taiga, and how the carbon dioxide absorbed or emitted should be treated by carbon accounting is controversial. Picea glauca taiga

Climate and geography

Taiga covers or 11.5% of the Earth's land area, second only to deserts and xeric shrublands. The largest areas are located in Russia and Canada. In

taiga is associated with the Norrland terrain.

Temperature

After the permanent ice caps and tundra, taiga is the terrestrial biome with the lowest annual average temperatures, with mean annual temperature generally varying from . Extreme winter minimums in the northern taiga are typically lower than those of the tundra. There are taiga areas of eastern Siberia and interior Alaska- Yukon where the mean annual reaches down to , and the lowest reliably recorded temperatures in the

Northern Hemisphere The Northern Hemisphere is the half of Earth that is north of the Equator. For other planets in the Solar System, north is defined as being in the same celestial hemisphere relative to the invariable plane of the solar system as Earth's Nort ...

were recorded in the taiga of northeastern Russia. Talkessel von Werchojansk

Taiga has a

subarctic climate The subarctic climate (also called subpolar climate, or boreal climate) is a climate with long, cold (often very cold) winters, and short, warm to cool summers. It is found on large landmasses, often away from the moderating effects of an ocean, ge ...

with very large temperature range between seasons. would be a typical winter day temperature and an average summer day, but the long, cold winter is the dominant feature. This climate is classified as ''Dfc'', ''Dwc'', ''Dsc'', ''Dfd'' and ''Dwd'' in the Köppen climate classification scheme, meaning that the short summers (24 h average or more), although generally warm and humid, only last 1–4 months, while winters, with average temperatures below freezing, last 5–7 months. In Siberian taiga the average temperature of the coldest month is between and .''Encyclopedia Universalis'' édition 1976 Vol. 2 ASIE – Géographie physique, p. 568 There are also some much smaller areas grading towards the oceanic ''Cfc'' climate with milder winters, whilst the extreme south and (in Eurasia) west of the taiga reaches into humid continental climates (''Dfb'', ''Dwb'') with longer summers. According to some sources, the boreal forest grades into a temperate mixed forest when mean annual temperature reaches about . Discontinuous permafrost is found in areas with mean annual temperature below freezing, whilst in the ''Dfd'' and ''Dwd'' climate zones continuous permafrost occurs and restricts growth to very shallow-rooted trees like Siberian larch.

Growing season

The

growing season A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. Whil ...

, when the vegetation in the taiga comes alive, is usually slightly longer than the climatic definition of summer as the plants of the boreal biome have a lower temperature threshold to trigger growth than other plants. Some sources claim 130 days growing season as typical for the taiga. In Canada and Scandinavia, the growing season is often estimated by using the period of the year when the 24-hour average temperature is or more. For the Taiga Plains in Canada, growing season varies from 80 to 150 days, and in the Taiga Shield from 100 to 140 days. Other sources define growing season by frost-free days. Data for locations in southwest Yukon gives 80–120 frost-free days. The closed canopy boreal forest in Kenozersky National Park near Plesetsk, Arkhangelsk Province, Russia, on average has 108 frost-free days. The longest growing season is found in the smaller areas with oceanic influences; in coastal areas of Scandinavia and Finland, the growing season of the closed boreal forest can be 145–180 days. The shortest growing season is found at the northern taiga–tundra ecotone, where the northern taiga forest no longer can grow and the tundra dominates the landscape when the growing season is down to 50–70 days, and the 24-hr average of the warmest month of the year usually is or less. High latitudes mean that the sun does not rise far above the horizon, and less

solar energy Solar energy is radiant light and heat from the Sun that is harnessed using a range of technologies such as solar power to generate electricity, solar thermal energy (including solar water heating), and solar architecture. It is an essenti ...

is received than further south. But the high latitude also ensures very long summer days, as the sun stays above the horizon nearly 20 hours each day, or up to 24 hours, with only around 6 hours of daylight, or none, occurring in the dark winters, depending on latitude. The areas of the taiga inside the

Arctic Circle The Arctic Circle is one of the two polar circles, and the most northerly of the five major circles of latitude as shown on maps of Earth. Its southern equivalent is the Antarctic Circle. The Arctic Circle marks the southernmost latitude at w ...

have midnight sun in mid-summer and polar night in mid-winter. Helvetinjärvi

Precipitation

The taiga experiences relatively low precipitation throughout the year (generally annually, in some areas), primarily as rain during the summer months, but also as snow or

fog Fog is a visible aerosol consisting of tiny water droplets or ice crystals suspended in the air at or near the Earth's surface. Reprint from Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influ ...

. Snow may remain on the ground for as long as nine months in the northernmost extensions of the taiga biome. The fog, especially predominant in low-lying areas during and after the thawing of frozen Arctic seas, stops sunshine from getting through to plants even during the long summer days. As

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when humidi ...

is consequently low for most of the year, annual precipitation exceeds evaporation, and is sufficient to sustain the dense vegetation growth including large trees. This explains the striking difference in biomass per square metre between the Taiga and the

Steppe In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes. Steppe biomes may include: * the montane grasslands and shrublands biome * the temperate grasslands, ...

biomes, (in warmer climates), where evapotranspiration exceeds precipitation, restricting vegetation to mostly grasses. Skjomtinden & Kongsbakktinden from Bogen, 2010 September

Skjomtinden & Kongsbakktinden from Bogen, 2010 September

In general, taiga grows to the south of the July isotherm, occasionally as far north as the July isotherm, with the southern limit more variable. Depending on rainfall, and taiga may be replaced by forest steppe south of the July isotherm where rainfall is very low, but more typically extends south to the July isotherm, and locally where rainfall is higher, such as in eastern Siberia and adjacent Outer Manchuria, south to the July isotherm. In these warmer areas the taiga has higher species diversity, with more warmth-loving species such as Korean pine, Jezo spruce, and

Manchurian fir ''Abies holophylla'', also called needle fir or Manchurian fir, is a species of fir native to mountainous regions of northern Korea, southern Ussuriland, and China in the provinces of Heilongjiang, Jilin, and Liaoning. It is an evergreen conif ...

, and merges gradually into mixed temperate forest or, more locally (on the Pacific Ocean coasts of North America and Asia), into coniferous temperate rainforests where oak and hornbeam appear and join the conifers, birch and Populus tremula.

Glaciation

The area currently classified as taiga in Europe and North America (except Alaska) was recently glaciated. As the glaciers receded they left depressions in the topography that have since filled with water, creating lakes and

bog A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; a ...

s (especially

muskeg Muskeg (Ojibwe: mashkiig; cr, maskīk; french: fondrière de mousse, lit. ''moss bog'') is a peat-forming ecosystem found in several northern climates, most commonly in Arctic and boreal areas. Muskeg is approximately synonymous with bog or ...

soil) found throughout the taiga. Yukon River near Carmacks, Yukon -a

Soils

Taiga soil tends to be young and poor in nutrients, lacking the deep, organically enriched profile present in temperate deciduous forests.Sayre, 19. The colder climate hinders development of soil, and the ease with which plants can use its nutrients. The relative lack of deciduous trees, which drop huge volumes of leaves annually, and grazing animals, which contribute significant manure, are also factors. The diversity of soil organisms in the boreal forest is high, comparable to the tropical rainforest. Fallen leaves and

moss Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) '' sensu stricto''. Bryophyta (''sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and hor ...

can remain on the forest floor for a long time in the cool, moist climate, which limits their organic contribution to the soil.

Acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a sequ ...

s from evergreen needles further leach the soil, creating spodosol, also known as podzol, and the acidic forest floor often has only lichens and some mosses growing on it. In clearings in the forest and in areas with more boreal deciduous trees, there are more herbs and berries growing, and soils are consequently deeper.

Flora

Since

and Eurasia were originally connected by the Bering land bridge, a number of animal and plant species (more animals than plants) were able to colonize both land masses, and are globally-distributed throughout the taiga biome (see Circumboreal Region). Others differ regionally (typically with each genus having several distinct species), each occupying different regions of the taiga. Taigas also have some small-leaved deciduous trees, like birch, alder, willow, and poplar; these grow mostly in areas further south of the most extreme winter weather. However, the Dahurian larch tolerates the coldest winters of the Northern Hemisphere, in eastern Siberia. The very southernmost parts of the taiga may have trees such as oak, maple, elm and lime scattered among the conifers, and there is usually a gradual transition into a temperate, mixed forest, such as the

eastern forest-boreal transition Eastern may refer to: Transportation *China Eastern Airlines, a current Chinese airline based in Shanghai *Eastern Air, former name of Zambia Skyways *Eastern Air Lines, a defunct American airline that operated from 1926 to 1991 *Eastern Air Li ...

of eastern Canada. In the interior of the continents, with the driest climates, the boreal forests might grade into temperate grassland. There are two major types of taiga. The southern part is the closed canopy forest, consisting of many closely-spaced trees and mossy groundcover. In clearings in the forest, shrubs and wildflowers are common, such as the fireweed and lupine. The other type is the lichen woodland or sparse taiga, with trees that are farther-spaced and

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.ice-pruned, asymmetric black spruce (in North America) are often seen, with diminished foliage on the windward side. In Canada, Scandinavia and Finland, the boreal forest is usually divided into three subzones: The high boreal (northern boreal/taiga zone), the middle boreal (closed forest), and the southern boreal, a closed-canopy, boreal forest with some scattered temperate, deciduous trees among the conifers. Commonly seen are species such as maple, elm and oak. This southern boreal forest experiences the longest and warmest growing season of the biome; in some regions (including Scandinavia and western Russia), this subzone is commonly used for agricultural purposes. The boreal forest is home to many types of berries. Some species are confined to the southern and middle closed-boreal forest (such as wild strawberry and partridgeberry); others grow in most areas of the taiga (such as cranberry and

cloudberry ''Rubus chamaemorus'' is a species of flowering plant in the rose family Rosaceae, native to cool temperate regions, alpine and arctic tundra and boreal forest. This herbaceous perennial produces amber-colored edible fruit similar to the blackbe ...

). Some berries can grow in both the taiga and the lower arctic (southern regions) tundra, such as bilberry, bunchberry and lingonberry. SevenlakesAlaska

The forests of the taiga are largely

, dominated by larch,

fir Firs (''Abies'') are a genus of 48–56 species of evergreen coniferous trees in the family (biology), family Pinaceae. They are found on mountains throughout much of North America, North and Central America, Europe, Asia, and North Africa. The ...

and pine. The woodland mix varies according to geography and climate; for example, the Eastern Canadian forests ecoregion (of the higher elevations of the Laurentian Mountains and the northern Appalachian Mountains) in Canada is dominated by balsam fir '' Abies balsamea'', while further north, the Eastern Canadian Shield taiga (of northern Quebec and Labrador) is mostly black spruce '' Picea mariana'' and tamarack larch ''

Larix laricina ''Larix laricina'', commonly known as the tamarack, hackmatack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland, and als ...

''. Evergreen species in the taiga (spruce, fir, and pine) have a number of adaptations specifically for survival in harsh taiga winters, although larch, which is extremely cold-tolerant, is deciduous. 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".Sayre, 23. The narrow conical shape of northern conifers, and their downward-drooping limbs, also help them shed snow. Because the sun is low in the horizon for most of the year, it is difficult for plants to generate energy from photosynthesis. Pine, spruce and fir do not lose their leaves seasonally and are able to photosynthesize with their older leaves in late winter and spring when light is good but temperatures are still too low for new growth to commence. The adaptation of evergreen needles limits the water lost due to transpiration and their dark green color increases their absorption of sunlight. Although precipitation is not a limiting factor, the ground freezes during the winter months and plant roots are unable to absorb water, so desiccation can be a severe problem in late winter for evergreens. Ptilium crista-castrensis

Although the taiga is dominated by coniferous forests, some

broadleaf trees A broad-leaved, broad-leaf, or broadleaf tree is any tree within the diverse botanical group of angiosperms that has flat leaves and produces seeds inside of fruits. It is one of two general types of trees, the other being a conifer, a tree with n ...

also occur, including birch, aspen, willow, and

rowan The rowans ( or ) or mountain-ashes are shrubs or trees in the genus ''Sorbus ''Sorbus'' is a genus of over 100 species of trees and shrubs in the rose family, Rosaceae. Species of ''Sorbus'' (''s.l.'') are commonly known as whitebeam, r ...

. Many smaller

herbaceous Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition of t ...

plants, such as ferns and occasionally ramps grow closer to the ground. Periodic stand-replacing wildfires (with return times of between 20 and 200 years) clear out the tree canopies, allowing sunlight to invigorate new growth on the forest floor. For some species, wildfires are a necessary part of the life cycle in the taiga; some, e.g. jack pine have cones which only open to release their seed after a fire, dispersing their seeds onto the newly cleared ground; certain species of fungi (such as

morels ''Morchella'', the true morels, is a genus of edible sac fungi closely related to anatomically simpler cup fungi in the order Pezizales (division Ascomycota). These distinctive fungi have a honeycomb appearance due to the network of ridges with ...

) are also known to do this. Grasses grow wherever they can find a patch of sun;

es and

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship. Coniferous trees are the dominant plants of the taiga biome. Very few species, in four main genera, are found: the evergreen spruce, fir and pine, and the deciduous larch. In North America, one or two species of fir, and one or two species of spruce, are dominant. Across Scandinavia and western Russia, the Scots pine is a common component of the taiga, while taiga of the Russian Far East and Mongolia is dominated by larch. Rich in spruce and Scots pine (in the western Siberian plain), the taiga is dominated by larch in Eastern Siberia, before returning to its original floristic richness on the Pacific shores. Two deciduous trees mingle throughout southern Siberia: birch and '' Populus tremula''.

Fauna

The boreal forest/taiga supports a relatively small variety of highly-specialized and adapted animals, due to the harshness of the climate. Canada's boreal forest includes 85 species of mammals, 130 species of fish, and an estimated 32,000 species of insects. Insects play a critical role as

pollinator A pollinator is an animal that moves pollen from the male anther of a flower to the female stigma of a flower. This helps to bring about fertilization of the ovules in the flower by the male gametes from the pollen grains. Insects are the maj ...

s, decomposers, and as a part of the food web. Many nesting birds, rodents, and small carnivorous mammals rely on them for food in the summer months. The cold winters (and short summers) make the taiga a challenging biome for

reptile Reptiles, as most commonly defined are the animals in the class Reptilia ( ), a paraphyletic grouping comprising all sauropsids except birds. Living reptiles comprise turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians ( ...

s and

amphibian Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...

s, which depend on environmental conditions to regulate their body temperatures; there are only a few species in the boreal forest, including

red-sided garter snake The red-sided garter snake (''Thamnophis sirtalis parietalis'') is a subspecies of the common garter snake, in the subfamily Natricinae of the family Colubridae. This slender subspecies of natricine snake is indigenous to North America and i ...

common European adder ''Vipera berus'', the common European adderMallow D, Ludwig D, Nilson G. (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. . or common European viper,Stidworthy J. (1974). ...

, blue-spotted salamander,

northern two-lined salamander The northern two-lined salamander (''Eurycea bislineata'') is a species of salamander in the family Plethodontidae found in Canada and the United States. Its natural habitats are temperate forests, temperate shrubland, rivers, intermittent river ...

, Siberian salamander, wood frog, northern leopard frog,

boreal chorus frog The boreal chorus frog (''Pseudacris maculata'') is a species of chorus frog native to Canada from central Quebec to eastern British Columbia and north to the Northwest Territories and the southern portion of the Yukon.Bee, M. A., Cook, J. M., L ...

, American toad, and

Canadian toad The Canadian toad (''Anaxyrus hemiophrys''), also known as the Dakota toad, is a species of toad that ranges from the prairie regions of western Canada south to parts of the United States upper midwest. It belongs to the family Bufonidae, the "tr ...

. Most hibernate underground in winter. Fish of the taiga must be able to withstand cold water conditions and be able to adapt to life under ice-covered water. Species in the taiga include Alaska blackfish, northern pike, walleye, longnose sucker, white sucker, various species of cisco, lake whitefish, round whitefish,

pygmy whitefish The pygmy whitefish (''Prosopium coulterii'') is a freshwater whitefish of the genus ''Prosopium'' in the family Salmonidae. Found in the mountain streams and lakes in western North America, it also has isolated populations in Lake Superior and i ...

Arctic lamprey The Arctic lamprey (''Lethenteron camtschaticum''), also known as the Japanese river lamprey or Japanese lampern (''Petromyzon japonicus'' Martens 1868, ''Lampetra fluviatilis japonica'' (Martens 1868), '' Lampetra japonica'' (Martens 1868), '' L ...

, various

grayling Grayling or Greyling may refer to: Animals Fish * Grayling, generically, any fish of the genus ''Thymallus'' in the family Salmonidae ** European grayling (''Thymallus thymallus''), the European species of the genus ''Thymallus'' ** Arctic grayli ...

species,

brook trout The brook trout (''Salvelinus fontinalis'') is a species of freshwater fish in the char genus ''Salvelinus'' of the salmon family Salmonidae. It is native to Eastern North America in the United States and Canada, but has been introduced elsewhere ...

(including sea-run brook trout in the Hudson Bay area),

chum salmon The chum salmon (''Oncorhynchus keta''), also known as dog salmon or keta salmon, is a species of anadromous salmonid fish from the genus '' Oncorhynchus'' (Pacific salmon) native to the coastal rivers of the North Pacific and the Beringian A ...

, Siberian taimen, lenok and lake chub. Snowscape (6701322581)

The taiga is mainly home to a number of large herbivorous

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

s, such as ''Alces alces'' ( moose), and a few subspecies of ''Rangifer tarandus'' ( reindeer in Eurasia);

caribou Reindeer (in North American English, known as caribou if wild and ''reindeer'' if domesticated) are deer in the genus ''Rangifer''. For the last few decades, reindeer were assigned to one species, ''Rangifer tarandus'', with about 10 subspe ...

in North America). Some areas of the more southern closed boreal forest have populations of other Cervidae species, such as the maral,

elk The elk (''Cervus canadensis''), also known as the wapiti, is one of the largest species within the deer family, Cervidae, and one of the largest terrestrial mammals in its native range of North America and Central and East Asia. The common ...

, Sitka black-tailed deer, and roe deer. While normally a polar species, some southern herds of muskoxen reside in the taiga of Russia's Far East and North America. The Amur-Kamchatka region of far eastern Russia also supports the snow sheep, the Russian relative of the American bighorn sheep, wild boar, and long-tailed goral. The largest animal in the taiga is the

wood bison The wood bison (''Bison bison athabascae'') or mountain bison (often called the wood buffalo or mountain buffalo), is a distinct northern subspecies or ecotype of the American bison. Its original range included much of the boreal forest regions ...

of northern Canada/Alaska; additionally, some numbers of the American plains bison have been introduced into the Russian far-east, as part of the taiga regeneration project called '' Pleistocene Park'', in addition to Przsewalski's horse. Small mammals of the taiga biome include rodent species such as the

beaver Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers ar ...

squirrel Squirrels are members of the family Sciuridae, a family that includes small or medium-size rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrels. Squ ...

, chipmunk, marmot, lemming, North American porcupine and vole; as well as a small number of lagomorph species, such as the pika, snowshoe hare and

mountain hare The mountain hare (''Lepus timidus''), also known as blue hare, tundra hare, variable hare, white hare, snow hare, alpine hare, and Irish hare, is a Palearctic hare that is largely adapted to polar and mountainous habitats. Evolution The mountai ...

. These species have adapted to survive the harsh winters in their native ranges. Some larger mammals, such as

bear Bears are carnivoran mammals of the family Ursidae. They are classified as caniforms, or doglike carnivorans. Although only eight species of bears are extant, they are widespread, appearing in a wide variety of habitats throughout the Nor ...

s, eat heartily during the summer in order to gain weight, and then go into

hibernation Hibernation is a state of minimal activity and metabolic depression undergone by some animal species. Hibernation is a seasonal heterothermy characterized by low body-temperature, slow breathing and heart-rate, and low metabolic rate. It most ...

during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold. Predatory mammals of the taiga must be adapted to travel long distances in search of scattered prey, or be able to supplement their diet with vegetation or other forms of food (such as raccoons). Mammalian predators of the taiga include Canada lynx, Eurasian lynx, stoat, Siberian weasel,

least weasel The least weasel (''Mustela nivalis''), little weasel, common weasel, or simply weasel is the smallest member of the genus '' Mustela,'' family Mustelidae and order Carnivora. It is native to Eurasia, North America and North Africa, and has bee ...

sable The sable (''Martes zibellina'') is a species of marten, a small omnivorous mammal primarily inhabiting the forest environments of Russia, from the Ural Mountains throughout Siberia, and northern Mongolia. Its habitat also borders eastern Kaza ...

American marten The American marten (''Martes americana''), also known as the American pine marten, is a species of North American mammal, a member of the family Mustelidae. The species is sometimes referred to as simply the pine marten. The name "pine marten" ...

, North American river otter, European otter, American mink, wolverine, Asian badger,

fisher Fisher is an archaic term for a fisherman, revived as gender-neutral. Fisher, Fishers or The Fisher may also refer to: Places Australia *Division of Fisher, an electoral district in the Australian House of Representatives, in Queensland *Elect ...

, timber wolf, Mongolian wolf,

coyote The coyote (''Canis latrans'') is a species of canis, canine native to North America. It is smaller than its close relative, the wolf, and slightly smaller than the closely related eastern wolf and red wolf. It fills much of the same ecologica ...

red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the Order (biology), order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe ...

, Arctic fox,

grizzly bear The grizzly bear (''Ursus arctos horribilis''), also known as the North American brown bear or simply grizzly, is a population or subspecies of the brown bear inhabiting North America. In addition to the mainland grizzly (''Ursus arctos horri ...

American black bear The American black bear (''Ursus americanus''), also called simply a black bear or sometimes a baribal, is a medium-sized bear endemic to North America. It is the continent's smallest and most widely distributed bear species. American black bear ...

, Asiatic black bear, Ussuri brown bear,

polar bear The polar bear (''Ursus maritimus'') is a hypercarnivorous bear whose native range lies largely within the Arctic Circle, encompassing the Arctic Ocean, its surrounding seas and surrounding land masses. It is the largest extant bear specie ...

(only small areas of northern taiga), Siberian tiger, and Amur leopard. More than 300 species of birds have their nesting grounds in the taiga. Siberian thrush, white-throated sparrow, and black-throated green warbler

migrate Migration, migratory, or migrate may refer to: Human migration * Human migration, physical movement by humans from one region to another ** International migration, when peoples cross state boundaries and stay in the host state for some minimum le ...

to this habitat to take advantage of the long summer days and abundance of insects found around the numerous bogs and lakes. Of the 300 species of birds that summer in the taiga, only 30 stay for the winter. These are either

carrion Carrion () is the decaying flesh of dead animals, including human flesh. Overview Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters (or scavengers) include crows, vultures, c ...

-feeding or large

raptor Raptor or RAPTOR may refer to: Animals The word "raptor" refers to several groups of bird-like dinosaurs which primarily capture and subdue/kill prey with their talons. * Raptor (bird) or bird of prey, a bird that primarily hunts and feeds on v ...

s that can take live mammal prey, such as the golden eagle, rough-legged buzzard (also known as the rough-legged hawk), Steller's sea eagle (in coastal northeastern Russia-Japan),

great gray owl The great grey owl (''Strix nebulosa'') (also great gray owl in American English) is a very large owl, documented as the world's largest species of owl by length. It is distributed across the Northern Hemisphere, and it is the only species in th ...

, snowy owl, barred owl, great horned owl, crow and

raven A raven is any of several larger-bodied bird species of the genus ''Corvus''. These species do not form a single taxonomic group within the genus. There is no consistent distinction between "crows" and "ravens", common names which are assigned t ...

. The only other viable adaptation is seed-eating birds, which include several species of grouse,

capercaillie ''Tetrao'' is a genus of birds in the grouse subfamily known as capercaillies. They are some of the largest living grouse. Taxonomy The genus ''Tetrao'' was introduced in 1758 by the Swedish naturalist Carl Linnaeus in the tenth edition of his ...

and crossbills.

Fire

Fire has been one of the most important factors shaping the composition and development of boreal forest stands; it is the dominant stand-renewing disturbance through much of the Canadian boreal forest. The fire history that characterizes an ecosystem is its ''fire regime'', which has 3 elements: (1) fire type and intensity (e.g., crown fires, severe surface fires, and light surface fires), (2) size of typical fires of significance, and (3) frequency or return intervals for specific land units. The average time within a fire regime to burn an area equivalent to the total area of an ecosystem is its ''fire rotation'' (Heinselman 1973) or ''fire cycle'' (Van Wagner 1978). However, as Heinselman (1981) noted, each physiographic site tends to have its own return interval, so that some areas are skipped for long periods, while others might burn two-times or more often during a nominal fire rotation. The dominant fire regime in the boreal forest is high-intensity crown fires or severe surface fires of very large size, often more than 10,000 ha (100 km²), and sometimes more than 400,000 ha (4000 km²). Such fires kill entire stands. Fire rotations in the drier regions of western Canada and Alaska average 50–100 years, shorter than in the moister climates of eastern Canada, where they may average 200 years or more. Fire cycles also tend to be long near the tree line in the subarctic spruce-lichen woodlands. The longest cycles, possibly 300 years, probably occur in the western boreal in floodplain white spruce. Amiro et al. (2001) calculated the mean fire cycle for the period 1980 to 1999 in the Canadian boreal forest (including taiga) at 126 years. Increased fire activity has been predicted for western Canada, but parts of eastern Canada may experience less fire in future because of greater precipitation in a warmer climate. The mature boreal forest pattern in the south shows balsam fir dominant on well-drained sites in eastern Canada changing centrally and westward to a prominence of white spruce, with

black spruce ''Picea mariana'', the black spruce, is a North American species of spruce tree in the pine family. It is widespread across Canada, found in all 10 provinces and all 3 territories. It is the official tree of the province of Newfoundland and Labra ...

and

tamarack ''Larix laricina'', commonly known as the tamarack, hackmatack, eastern larch, black larch, red larch, or American larch, is a species of larch native to Canada, from eastern Yukon and Inuvik, Northwest Territories east to Newfoundland, and als ...

forming the forests on peats, and with jack pine usually present on dry sites except in the extreme east, where it is absent.

3680, Coates et al. 1994 Year 368 ( CCCLXVIII) was a leap year starting on Tuesday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Augustus and Valens (or, less frequently, year 1121 ''Ab urbe co ...

/ref> The effects of fires are inextricably woven into the patterns of vegetation on the landscape, which in the east favour black spruce, paper birch, and jack pine over balsam fir, and in the west give the advantage to aspen, jack pine, black spruce, and birch over white spruce. Many investigators have reported the ubiquity of charcoal under the forest floor and in the upper soil profile. Charcoal in soils provided Bryson et al. (1965) with clues about the forest history of an area 280 km north of the then-current tree line at Ennadai Lake, District Keewatin, Northwest Territories. Shanta2 7-8-2009

Two lines of evidence support the thesis that fire has always been an integral factor in the boreal forest: (1) direct, eye-witness accounts and forest-fire statistics, and (2) indirect, circumstantial evidence based on the effects of fire, as well as on persisting indicators. The patchwork mosaic of forest stands in the boreal forest, typically with abrupt, irregular boundaries circumscribing homogenous stands, is indirect but compelling testimony to the role of fire in shaping the forest. The fact is that most boreal forest stands are less than 100 years old, and only in the rather few areas that have escaped burning are there stands of white spruce older than 250 years. The prevalence of fire-adaptive morphologic and reproductive characteristics of many boreal plant species is further evidence pointing to a long and intimate association with fire. Seven of the ten most common trees in the boreal forest— jack pine, lodgepole pine, aspen, balsam poplar (''Populus balsamifera''), paper birch,

– can be classed as pioneers in their adaptations for rapid invasion of open areas. White spruce shows some pioneering abilities, too, but is less able than black spruce and the pines to disperse seed at all seasons. Only balsam fir and alpine fir seem to be poorly adapted to reproduce after fire, as their cones disintegrate at maturity, leaving no seed in the crowns. The oldest forests in the northwest boreal region, some older than 300 years, are of white spruce occurring as pure stands on moist floodplains. Here, the frequency of fire is much less than on adjacent uplands dominated by pine, black spruce and aspen. In contrast, in the Cordilleran region, fire is most frequent in the valley bottoms, decreasing upward, as shown by a mosaic of young pioneer pine and broadleaf stands below, and older spruce–fir on the slopes above. Without fire, the boreal forest would become more and more homogeneous, with the long-lived white spruce gradually replacing pine, aspen, balsam poplar, and birch, and perhaps even black spruce, except on the peatlands.

Climate change

During the last quarter of the twentieth century, the zone of latitude occupied by the boreal forest experienced some of the greatest temperature increases on Earth. Winter temperatures have increased more than summer temperatures. In summer, the daily low temperature has increased more than the daily high temperature. The number of days with extremely cold temperatures (e.g., −20 to −40 °C (−4 to −40 °F) has decreased irregularly but systematically in nearly all the boreal region, allowing better survival for tree-damaging insects. In Fairbanks, Alaska, the length of the frost-free season has increased from 60 to 90 days in the early twentieth century to about 120 days a century later. It has been hypothesized that the boreal environments have only a few states which are stable in the long term - a treeless tundra/steppe, a forest with >75% tree cover and an open woodland with ∼20% and ∼45% tree cover. Thus, continued climate change would be able to force at least some of the presently existing taiga forests into one of the two woodland states or even into a treeless steppe - but it could also shift tundra areas into woodland or forest states as they warm and become more suitable for tree growth. In keeping with this hypothesis, several studies published in the early 2010s found that there was already a substantial drought-induced tree loss in the western Canadian boreal forests since the 1960s: although this trend was weak or even non-existent in the eastern forests, it was particularly pronounced in the western coniferous forests. However, in 2016, a study found no overall Canadian boreal forest trend between 1950 and 2012: while it also found improved growth in some southern boreal forests and dampened growth in the north (contrary to what the hypothesis would suggest), those patterns were statistically weak. A 2018 Landsat reanalysis confirmed that there was a drying trend and a loss of forest in western Canadian forests and some greening in the wetter east, but it had also concluded that most of the forest loss attributed to climate change in the earlier studies had instead constituted a delayed response to anthropogenic disturbance. Subsequent research found that even in the forests where biomass trends did not change, there was a substantial shift towards the deciduous broad-leaved trees with higher drought tolerance over the past 65 years, and another Landsat analysis of 100,000 undisturbed sites found that the areas with low tree cover became greener in response to warming, but tree mortality (browning) became the dominant response as the proportion of existing tree cover increased. While the majority of studies on boreal forest transitions have been done in Canada, similar trends have been detected in the other countries. Summer warming has been shown to increase water stress and reduce tree growth in dry areas of the southern boreal forest in central Alaska and portions of far eastern Russia.In Siberia, the taiga is converting from predominantly needle-shedding larch trees to evergreen conifers in response to a warming climate. This is likely to further accelerate warming, as the evergreen trees will absorb more of the sun's rays. Given the vast size of the area, such a change has the potential to affect areas well outside of the region. In much of the boreal forest in Alaska, the growth of white spruce trees are stunted by unusually warm summers, while trees on some of the coldest fringes of the forest are experiencing faster growth than previously. Lack of moisture in the warmer summers are also stressing the birch trees of central Alaska. 2018 boreal tree species trends

In addition to these observations, there has also been work on projecting future forest trends. A 2018 study of the seven tree species dominant in the Eastern Canadian forests found that while 2°C warming alone increases their growth by around 13% on average, water availability is much more important than temperature and further warming of up to 4°C would result in substantial declines unless matched by increases in precipitation. A 2019 study suggested that the forest plots commonly used to evaluate boreal forest response to climate change tend to have less evolutionary competition between trees than the typical forest, and that with strong competition, there was little net growth in response to warming. Climatic change only stimulated growth for trees under weak competition in central boreal forests. A 2021 paper had confirmed that the boreal forests are much more strongly affected by climate change than the other forest types in Canada and projected that most of the eastern Canadian boreal forests would reach a tipping point around 2080 under the RCP 8.5 scenario which represents the largest potential increase in anthropogenic emissions. Another 2021 study projected that under the "moderate" SSP2-4.5 scenario, boreal forests would experience a 15% worldwide increase in biomass by the end of the century, but this would be more than offset by the 41% biomass decline in the tropics. In 2022, the results of a 5-year warming experiment in North America had shown that the juveniles of tree species which currently dominate the southern margins of the boreal forests fare the worst in response to even 1.5°C or +3.1 °C of warming and the associated reductions in precipitation. While the temperate species which would benefit from such conditions are also present in the southern boreal forests, they are both rare and have slower growth rates. A 2022 assessment of tipping points in the climate system designated two inter-related tipping points associated with climate change - the die-off of taiga at its southern edge and the area's consequent reversion to grassland (similar to the

Amazon rainforest The Amazon rainforest, Amazon jungle or ; es, Selva amazónica, , or usually ; french: Forêt amazonienne; nl, Amazoneregenwoud. In English, the names are sometimes capitalized further, as Amazon Rainforest, Amazon Forest, or Amazon Jungle. ...

dieback) and the opposite process to the north, where the rapid warming of the adjacent tundra areas converts them to taiga. While both of these processes can already be observed today, the assessment believes that they would likely not become unstoppable (and thus meet the definition of a tipping point) until global warming of around 4 °C. However, the certainty level is still limited and it is possible that 1.5 °C would be sufficient for either tipping point; on the other hand, the southern die-off may not be inevitable until 5 °C, while the replacement of tundra with taiga may require 7.2°C. Once the "right" level of warming is met, either process would take at least 40-50 years to finish, and is more likely to unfold over a century or more. While the southern die-off would involve the loss of around 52 billion tons of carbon, the net result is ''cooling'' of around 0.18°C globally and between 0.5°C to 2°C regionally. Likewise, boreal forest expansion into tundra has a net global warming effect of around 0.14°C globally and 0.5°C to 1°C regionally, even though new forest growth captures around 6 billion tons of carbon. In both cases, this is due to the snow-covered ground having a much greater albedo than the forests.

Other threats

Human activities

Plesetsk satellite assembling facilities

Some of the larger cities situated in this biome are Murmansk, Arkhangelsk, Yakutsk,

Anchorage Anchorage () is the largest city in the U.S. state of Alaska by population. With a population of 291,247 in 2020, it contains nearly 40% of the state's population. The Anchorage metropolitan area, which includes Anchorage and the neighboring Ma ...

, Yellowknife, Tromsø,

Luleå Luleå ( , , locally ; smj, Luleju; fi, Luulaja) is a city on the coast of northern Sweden, and the capital of Norrbotten County, the northernmost county in Sweden. Luleå has 48,728 inhabitants in its urban core (2018) and is the seat of Lu ...

, and

Oulu Oulu ( , ; sv, Uleåborg ) is a city, municipality and a seaside resort of about 210,000 inhabitants in the region of North Ostrobothnia, Finland. It is the most populous city in northern Finland and the fifth most populous in the country after: ...

. Large areas of Siberia's taiga have been harvested for lumber since the collapse of the Soviet Union. Previously, the forest was protected by the restrictions of the Soviet Forest Ministry, but with the collapse of the Union, the restrictions regarding trade with Western nations have vanished. Trees are easy to harvest and sell well, so loggers have begun harvesting Russian taiga evergreen trees for sale to nations previously forbidden by Soviet law. In Canada, only eight percent of the taiga is protected from development, and the provincial governments allows

clearcutting Clearcutting, clearfelling or clearcut logging is a forestry/ logging practice in which most or all trees in an area are uniformly cut down. Along with shelterwood and seed tree harvests, it is used by foresters to create certain types of fore ...

to occur on Crown land, which destroys the forest in large blocks. The blocks are replanted with monocrop seedlings in the following season, but the trees do not grow back for many years, and the forest ecosystem is radically changed for hundreds of years. Products from logged boreal forests include toilet paper,

copy paper Copy may refer to: * Copying or the product of copying (including the plural "copies"); the duplication of information or an artifact ** Cut, copy and paste, a method of reproducing text or other data in computing ** File copying **Photocopying, a ...

newsprint Newsprint is a low-cost, non-archival paper consisting mainly of wood pulp and most commonly used to print newspapers and other publications and advertising material. Invented in 1844 by Charles Fenerty of Nova Scotia, Canada, it usually has an ...

, and lumber. More than 90% of boreal forest products from Canada are exported for consumption and processing in the United States. Most companies that harvest in Canadian forests use some certification by agencies such as the Forest Stewardship Council (FSC), Sustainable Forests Initiative (SFI), or the Canadian Standards Association (CSA), in their marketing. While the certification process differs between these groups, all of them include some mention of undefined "forest stewardship", "respect for aboriginal peoples", and compliance with local, provincial or national environmental laws, forest worker safety, education and training, and other issues. The certification is largely about tracking, to ensure traceability, and does not de-certify lumber obtained from clearcuts, or taken without the consent of aboriginal peoples.

Insects

Recent years have seen outbreaks of insect pests in forest-destroying plagues: the spruce-bark beetle ('' Dendroctonus rufipennis'') in Yukon and Alaska; the mountain pine beetle in British Columbia; the aspen-leaf miner; the

larch sawfly ''Pristiphora erichsonii'', the larch sawfly, is a species of sawfly. The adult sawfly resembles a black wasp A wasp is any insect of the narrow-waisted suborder Apocrita of the order Hymenoptera which is neither a bee nor an ant; this ...

; the spruce budworm ('' Choristoneura fumiferana''); the spruce coneworm.

Pollution

The effect of

sulphur dioxide Sulfur dioxide (IUPAC-recommended spelling) or sulphur dioxide (traditional Commonwealth English) is the chemical compound with the formula . It is a toxic gas responsible for the odor of burnt matches. It is released naturally by volcanic activ ...

on woody boreal forest species was investigated by Addison et al. (1984),Addison, P.A.; Malhotra, S.S.; Khan, A.A. 1984. "Effect of sulfur dioxide on woody boreal forest species grown on native soils and tailings". ''J. Environ. Qual.'' 13(3):333–36. who exposed plants growing on native soils and tailings to 15.2 μmol/m³ (0.34 ppm) of SO₂ on CO₂ assimilation rate (NAR). The Canadian maximum acceptable limit for atmospheric SO₂ is 0.34 ppm. Fumigation with SO₂ significantly reduced NAR in all species and produced visible symptoms of injury in 2–20 days. The decrease in NAR of deciduous species (trembling aspen 'Populus tremuloides'' willow 'Salix'' green alder 'Alnus viridis'' and white birch 'Betula papyrifera'' was significantly more rapid than of

conifers Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extan ...

(white spruce, black spruce 'Picea mariana'' and jack pine 'Pinus banksiana'' or an evergreen angiosperm (Labrador tea) growing on a fertilized Brunisol. These metabolic and visible injury responses seemed to be related to the differences in S uptake owing in part to higher gas exchange rates for deciduous species than for

. Conifers growing in oil sands tailings responded to SO₂ with a significantly more rapid decrease in NAR compared with those growing in the Brunisol, perhaps because of predisposing toxic material in the tailings. However,

sulphur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

uptake and visible symptom development did not differ between conifers growing on the 2 substrates. Acidification of precipitation by anthropogenic, acid-forming emissions has been associated with damage to vegetation and reduced forest productivity, but 2-year-old white spruce that were subjected to simulated

acid rain Acid rain is rain or any other form of precipitation that is unusually acidic, meaning that it has elevated levels of hydrogen ions (low pH). Most water, including drinking water, has a neutral pH that exists between 6.5 and 8.5, but acid ...

(at pH 4.6, 3.6, and 2.6) applied weekly for 7 weeks incurred no statistically significant (P 0.05) reduction in growth during the experiment compared with the background control (pH 5.6) (Abouguendia and Baschak 1987).Abouguendia, Z.M.; Baschak, L.A. 1987. "Response of two western Canadian conifers to simulated acidic precipitation". ''Water, Air and Soil Pollution'' 33:15–22. However, symptoms of injury were observed in all treatments, the number of plants and the number of needles affected increased with increasing rain acidity and with time. Scherbatskoy and Klein (1983)Scherbatskoy, T.; Klein, R.M. 1983. "Response of spruce Picea glauca and birch Betula alleghaniensis foliage to leaching by acidic mists". ''J. Environ. Qual.'' 12:189–95. found no significant effect of

chlorophyll Chlorophyll (also chlorophyl) is any of several related green pigments found in cyanobacteria and in the chloroplasts of algae and plants. Its name is derived from the Greek words , ("pale green") and , ("leaf"). Chlorophyll allow plants to a ...

concentration in white spruce at pH 4.3 and 2.8, but Abouguendia and Baschak (1987) found a significant reduction in white spruce at pH 2.6, while the foliar sulphur content significantly greater at pH 2.6 than any of the other treatments.

Protection

The taiga stores enormous quantities of carbon, more than the world's temperate and tropical forests combined, much of it in wetlands and peatland. In fact, current estimates place boreal forests as storing twice as much carbon per unit area as tropical forests. Wildfires could use up a significant part of the global carbon budget, so fire management at about 12 dollars per tonne of carbon not released is very cheap compared to the social cost of carbon. Some nations are discussing protecting areas of the taiga by prohibiting

logging Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidding, on-site processing, and loading of trees or logs onto trucks or skeleton cars. Logging is the beginning of a supply chain ...

, mining, oil and gas production, and other forms of development. Responding to a letter signed by 1,500 scientists calling on political leaders to protect at least half of the boreal forest, two Canadian provincial governments, Ontario and Quebec, offered election promises to discuss measures in 2008 that might eventually classify at least half of their northern boreal forest as "protected". Although both provinces admitted it would take decades to plan, working with Aboriginal and local communities and ultimately mapping out precise boundaries of the areas off-limits to development, the measures were touted to create some of the largest protected areas networks in the world once completed. Since then, however, very little action has been taken. For instance, in February 2010 the Canadian government established limited protection for 13,000 square kilometres of boreal forest by creating a new 10,700-square-kilometre park reserve in the Mealy Mountains area of eastern Canada and a 3,000-square-kilometre waterway provincial park that follows alongside the Eagle River from headwaters to sea.

Natural disturbance

One of the biggest areas of research and a topic still full of unsolved questions is the recurring disturbance of fire and the role it plays in propagating the lichen woodland.Kurkowski, 1911. The phenomenon of wildfire by lightning strike is the primary determinant of understory vegetation, and because of this, it is considered to be the predominant force behind community and ecosystem properties in the lichen woodland.Nilsson, 421. The significance of fire is clearly evident when one considers that understory vegetation influences tree seedling germination in the short term and decomposition of biomass and nutrient availability in the long term. The recurrent cycle of large, damaging fire occurs approximately every 70 to 100 years. Understanding the dynamics of this ecosystem is entangled with discovering the successional paths that the vegetation exhibits after a fire. Trees, shrubs, and lichens all recover from fire-induced damage through vegetative reproduction as well as invasion by propagules.Johnson, 200 Seeds that have fallen and become buried provide little help in re-establishment of a species. The reappearance of lichens is reasoned to occur because of varying conditions and light/nutrient availability in each different microstate. Several different studies have been done that have led to the formation of the theory that post-fire development can be propagated by any of four pathways: self replacement, species-dominance relay, species replacement, or gap-phase self replacement. Self-replacement is simply the re-establishment of the pre-fire dominant species. Species-dominance relay is a sequential attempt of tree species to establish dominance in the canopy. Species replacement is when fires occur in sufficient frequency to interrupt species dominance relay. Gap-Phase Self-Replacement is the least common and so far has only been documented in Western Canada. It is a self replacement of the surviving species into the canopy gaps after a fire kills another species. The particular pathway taken after fire disturbance depends on how the landscape is able to support trees as well as fire frequency. Fire frequency has a large role in shaping the original inception of the lower forest line of the lichen woodland taiga. It has been hypothesized by Serge Payette that the spruce-moss forest ecosystem was changed into the lichen woodland biome due to the initiation of two compounded strong disturbances: large fire and the appearance and attack of the spruce budworm.Payette, 289. The spruce budworm is a deadly insect to the spruce populations in the southern regions of the taiga. J.P. Jasinski confirmed this theory five years later stating, "Their ichen woodlandspersistence, along with their previous moss forest histories and current occurrence adjacent to closed moss forests, indicate that they are an

alternative stable state In ecology, the theory of alternative stable states (sometimes termed alternate stable states or alternative stable equilibria) predicts that ecosystems can exist under multiple "states" (sets of unique biotic and abiotic conditions). These alterna ...

to the spruce–moss forests".Jasinski, 561.

Taiga ecoregions

References

;General references * * * * * * * *

External links

The Conservation Value of the North American Boreal Forest from an Ethnobotanical perspective
a report by th
Boreal Songbird InitiativeBoreal Canadian InitiativeBoreal Forests
Project Regeneration
International Boreal Conservation campaignThreats to Boreal Forests
Greenpeace
Campaign against lumber giant Weyerhaeuser's logging practices in the Canadian boreal forest
Rainforest Action Network
Arctic and Taiga
Canadian Geographic
Terraformers
Canadian Taiga Conservation Foundation

NASA
Taiga Rescue Network (TRN)
A network of NGOs, indigenous peoples or individuals that works to protect the boreal forests.

at bioimages.vanderbilt.edu

The Nature Conservancy and its partners
Slater museum of natural history: Taiga
founded by Dr. William (Bill) Pruitt, Jr., University of Manitoba. {{Authority control Terrestrial biomes Forests Köppen climate types Physiographic provinces Subarctic Turkic words and phrases