Taiga

Taiga

Overview
Taiga also known as the boreal forest, is a biome
Biome
Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a...

 characterized by coniferous forests.

Taiga is the world's largest terrestrial biome. In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 it covers most of inland Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 and Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 as well as parts of the extreme northern continental United States and is known as the Northwoods. It also covers most of Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

, Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

, inland and northern Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

, much of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 (especially Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

), northern Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...

, northern Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

, and northern Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 (on the island of Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...

).

The term boreal forest is sometimes, particularly in Canada, used to refer to the more southerly part of the biome, while the term taiga is often used to describe the more barren areas of the northernmost part of the taiga approaching the tree line.


Taiga is the world's largest land biome, and makes up 29% of the world's forest cover; the largest areas are located in Russia and Canada.
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Encyclopedia
Taiga also known as the boreal forest, is a biome
Biome
Biomes are climatically and geographically defined as similar climatic conditions on the Earth, such as communities of plants, animals, and soil organisms, and are often referred to as ecosystems. Some parts of the earth have more or less the same kind of abiotic and biotic factors spread over a...

 characterized by coniferous forests.

Taiga is the world's largest terrestrial biome. In North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 it covers most of inland Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 and Alaska
Alaska
Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 as well as parts of the extreme northern continental United States and is known as the Northwoods. It also covers most of Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

, Finland
Finland
Finland , officially the Republic of Finland, is a Nordic country situated in the Fennoscandian region of Northern Europe. It is bordered by Sweden in the west, Norway in the north and Russia in the east, while Estonia lies to its south across the Gulf of Finland.Around 5.4 million people reside...

, inland and northern Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

, much of Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...

 (especially Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

), northern Kazakhstan
Kazakhstan
Kazakhstan , officially the Republic of Kazakhstan, is a transcontinental country in Central Asia and Eastern Europe. Ranked as the ninth largest country in the world, it is also the world's largest landlocked country; its territory of is greater than Western Europe...

, northern Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

, and northern Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 (on the island of Hokkaidō
Hokkaido
, formerly known as Ezo, Yezo, Yeso, or Yesso, is Japan's second largest island; it is also the largest and northernmost of Japan's 47 prefectural-level subdivisions. The Tsugaru Strait separates Hokkaido from Honshu, although the two islands are connected by the underwater railway Seikan Tunnel...

).

The term boreal forest is sometimes, particularly in Canada, used to refer to the more southerly part of the biome, while the term taiga is often used to describe the more barren areas of the northernmost part of the taiga approaching the tree line.

Climate and geography


Taiga is the world's largest land biome, and makes up 29% of the world's forest cover; the largest areas are located in Russia and Canada. The taiga is the terrestrial biome with the lowest annual average temperatures after the tundra
Tundra
In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...

 and permanent ice caps. However, extreme minimums in the taiga are typically lower than those of the tundra. The lowest reliably recorded temperatures in the Northern Hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...

 were recorded in the taiga of northeastern Russia. The taiga or boreal forest has a subarctic climate
Subarctic climate
The subarctic climate is a climate characterized by long, usually very cold winters, and short, cool to mild summers. It is found on large landmasses, away from the moderating effects of an ocean, generally at latitudes from 50° to 70°N poleward of the humid continental climates...

 with very large temperature range between seasons, but the long and cold winter is the dominant feature. This climate is classified as Dfc, Dwc, Dsc, Dfd and Dwd in the Köppen climate classification
Köppen climate classification
The Köppen climate classification is one of the most widely used climate classification systems. It was first published by Crimea German climatologist Wladimir Köppen in 1884, with several later modifications by Köppen himself, notably in 1918 and 1936...

 scheme, meaning that the short summer (24-hr average 10 °C or more) lasts 1–3 months and always less than 4 months. 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 climate
Humid continental climate
A humid continental climate is a climatic region typified by large seasonal temperature differences, with warm to hot summers and cold winters....

s (Dfb, Dwb) with longer summers. The mean annual temperature generally varies from -5 °C to 5 °C, but there are taiga areas in eastern Siberia and interior Alaska-Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....

 where the mean annual reaches down to -10 °C. According to some sources, the boreal forest grades into a temperate mixed forest when mean annual temperature reaches about 3 °C. Discontinuous permafrost is found in areas with mean annual temperature below 0 °C, whilst in the Dfd and Dwd climate zones continuous permafrost occurs and restricts growth to very shallow-rooted trees like Siberian larch
Siberian Larch
The Siberian Larch or Russian Larch is a frost-hardy tree native to western Russia, from close to the Finnish border east to the Yenisei valley in central Siberia, where it hybridises with the Dahurian Larch L...

. The winters, with average temperatures below freezing, last five to seven months. Temperatures vary from −54 °C to 30 °C (-65 °F to 86 °F) throughout the whole year. The summers, while short, are generally warm and humid. In much of the taiga, -20 °C would be a typical winter day temperature and 18 °C an average summer day.
The growing season
Growing season
In botany, horticulture, and agriculture the growing season is the period of each year when native plants and ornamental plants grow; and when crops can be grown....

, 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 threshold to trigger growth. In Canada, Scandinavia and Finland, the growing season is often estimated by using the period of the year when the 24-hr average temperature is 5 °C 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. Some sources claim 130 days growing season as typical for the taiga. Other sources mention that 50–100 frost-free days are characteristic. Data for locations in southwest Yukon gives 80–120 frost-free days. The closed canopy boreal forest in Kenozyorsky National Park
Kenozyorsky National Park
Kenozyorsky National Park is the national park in the north of Russia, located in Kargopolsky and Plesetsky Districts of Arkhangelsk Oblast. It was established December 28, 1991. Since 2004, the National Park has the status of the UNESCO Biosphere Reserve.- History :Kenozero was always a...

 near Plesetsk
Plesetsk
Plesetsk is an urban locality Plesetsk is an urban locality Plesetsk is an urban locality (a work settlement and the administrative center of Plesetsky District, Arkhangelsk Oblast, Russia, situated about northeast of Moscow and south of Arkhangelsk. Municipally, it is the administrative...

, Arkhangelsk Province
Arkhangelsk Oblast
Arkhangelsk Oblast is a federal subject of Russia . It includes the Arctic archipelagos of Franz Josef Land and Novaya Zemlya, as well as the Solovetsky Islands in the White Sea....

, 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
Ecotone
An ecotone is a transition area between two biomes but different patches of the landscape, such as forest and grassland. It may be narrow or wide, and it may be local or regional...

, 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 10 °C or less. High latitude
Latitude
In geography, the latitude of a location on the Earth is the angular distance of that location south or north of the Equator. The latitude is an angle, and is usually measured in degrees . The equator has a latitude of 0°, the North pole has a latitude of 90° north , and the South pole has a...

s mean that the sun
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...

 does not rise far above the horizon, and less solar energy 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, with only around 6 hours of daylight occurring in the dark winters, depending on latitude. The areas of the taiga inside the Arctic circle
Arctic Circle
The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. For Epoch 2011, it is the parallel of latitude that runs north of the Equator....

 have midnight sun
Midnight sun
The midnight sun is a natural phenomenon occurring in summer months at latitudes north and nearby to the south of the Arctic Circle, and south and nearby to the north of the Antarctic Circle where the sun remains visible at the local midnight. Given fair weather, the sun is visible for a continuous...

 in mid-summer and polar night
Polar night
The polar night occurs when the night lasts for more than 24 hours. This occurs only inside the polar circles. The opposite phenomenon, the polar day, or midnight sun, occurs when the sun stays above the horizon for more than 24 hours.-Description:...

 in mid-winter.
The taiga experiences relatively low precipitation
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...

 throughout the year (generally 200–750 mm annually, 1,000 mm in some areas), primarily as rain
Rain
Rain is liquid precipitation, as opposed to non-liquid kinds of precipitation such as snow, hail and sleet. Rain requires the presence of a thick layer of the atmosphere to have temperatures above the melting point of water near and above the Earth's surface...

 during the summer months, but also as fog
Fog
Fog is a collection of water droplets or ice crystals suspended in the air at or near the Earth's surface. While fog is a type of stratus cloud, the term "fog" is typically distinguished from the more generic term "cloud" in that fog is low-lying, and the moisture in the fog is often generated...

 and snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...

. This fog, especially predominant in low-lying areas during and after the thawing of frozen Arctic seas, means that sunshine is not abundant in the taiga even during the long summer days. As evaporation
Evaporation
Evaporation is a type of vaporization of a liquid that occurs only on the surface of a liquid. The other type of vaporization is boiling, which, instead, occurs on the entire mass of the liquid....

 is consequently low for most of the year, precipitation exceeds evaporation, and is sufficient to sustain the dense vegetation growth. Snow may remain on the ground for as long as nine months in the northernmost extensions of the taiga ecozone.

In general, taiga grows to the south of the 10 °C July isotherm, but occasionally as far north as the 9 °C July isotherm. The southern limit is more variable, depending on rainfall; taiga may be replaced by forest steppe
Forest steppe
A forest steppe is a temperate-climate ecotone and habitat type composed of grassland interspersed with areas of woodland or forest.-Locations:...

 south of the 15 °C July isotherm where rainfall is very low, but more typically extends south to the 18 °C July isotherm, and locally where rainfall is higher (notably in eastern Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

 and adjacent northern Manchuria
Manchuria
Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast...

) south to the 20 °C July isotherm. In these warmer areas the taiga has higher species diversity, with more warmth-loving species such as Korean Pine
Korean Pine
The tree species Pinus koraiensis is commonly called Korean Pine. It is native to eastern Asia, Korea, Manchuria, far eastern Russia, and central Japan. In the north of its range, it grows at moderate altitudes, typically to , whereas further south, it is a mountain tree, growing at to altitude...

, Jezo Spruce
Jezo Spruce
The Jezo spruce or Yezo spruce is a large evergreen tree growing to 30-50 m tall and with a trunk diameter of up to 2 m...

, and Manchurian Fir
Manchurian Fir
Manchurian Fir , also called Needle 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....

, and merges gradually into mixed temperate forest
Temperate broadleaf and mixed forests
Mixed forests are a temperate and humid biome. The typical structure of these forests includes four layers. The uppermost layer is the canopy composed of tall mature trees ranging from 33 to 66 m high. Below the canopy is the three-layered, shade-tolerant understory that is roughly 9 to...

 or, more locally (on the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...

 coasts of North America and Asia), into coniferous temperate rainforests.

The area currently classified as taiga in Europe and North America (except Alaska) was recently glaciated
Wisconsin glaciation
The last glacial period was the most recent glacial period within the current ice age occurring during the last years of the Pleistocene, from approximately 110,000 to 10,000 years ago....

. As the glaciers receded they left depressions
Kettle (geology)
A kettle is a shallow, sediment-filled body of water formed by retreating glaciers or draining floodwaters.-Overview:...

 in the topography that have since filled with water, creating lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

s and bog
Bog
A bog, quagmire or mire is a wetland that accumulates acidic peat, a deposit of dead plant material—often mosses or, in Arctic climates, lichens....

s (especially muskeg
Muskeg
Muskeg is an acidic soil type common in Arctic and boreal areas, although it is found in other northern climates as well. Muskeg is approximately synonymous with bogland but muskeg is the standard term in Western Canada and Alaska, while 'bog' is common elsewhere. The term is of Cree origin, maskek...

 soil) found throughout the taiga.

Soils


Taiga soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...

 tends to be young and poor in nutrients. It lacks the deep, organically enriched profile present in temperate deciduous forests. The thinness of the soil is due largely to the cold, which hinders the development of soil and the ease with which plants can use its nutrients. Fallen leaves and moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...

 can remain on the forest floor
Forest floor
The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...

 for a long time in the cool, moist climate, which limits their organic contribution to the soil; acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s from evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 needles further leach the soil, creating spodosol, also known as podzol. Since the soil is acidic due to the falling pine needles, the forest floor 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. Diversity of soil organisms in the boreal forest is high, comparable to the tropical rainforest. .

Flora



Since North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...

 and Asia
Asia
Asia is the world's largest and most populous continent, located primarily in the eastern and northern hemispheres. It covers 8.7% of the Earth's total surface area and with approximately 3.879 billion people, it hosts 60% of the world's current human population...

 used to be connected by the Bering land bridge
Bering land bridge
The Bering land bridge was a land bridge roughly 1,000 miles wide at its greatest extent, which joined present-day Alaska and eastern Siberia at various times during the Pleistocene ice ages. Like most of Siberia and all of Manchuria, Beringia was not glaciated because snowfall was extremely light...

, a number of animal and plant species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 (more animals than plants) were able to colonize both continents and are distributed throughout the taiga biome (see Circumboreal Region
Circumboreal Region
The Circumboreal Region is a floristic region within the Holarctic Kingdom in Eurasia and North America, as delineated by such geobotanists as Josias Braun-Blanquet and Armen Takhtajan....

). Others differ regionally, typically with each genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 having several distinct species, each occupying different regions of the taiga. Taigas also have some small-leaved deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

 trees like birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...

, alder
Alder
Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...

, willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...

, and poplar; mostly in areas escaping the most extreme winter cold. However, the Dahurian Larch tolerates the coldest winters in the northern hemisphere in eastern Siberia. The very southernmost parts of the taiga may have trees such as oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...

, maple
Maple
Acer is a genus of trees or shrubs commonly known as maple.Maples are variously classified in a family of their own, the Aceraceae, or together with the Hippocastanaceae included in the family Sapindaceae. Modern classifications, including the Angiosperm Phylogeny Group system, favour inclusion in...

, elm
Elm
Elms are deciduous and semi-deciduous trees comprising the genus Ulmus in the plant family Ulmaceae. The dozens of species are found in temperate and tropical-montane regions of North America and Eurasia, ranging southward into Indonesia. Elms are components of many kinds of natural forests...

, and tilia
Tilia
Tilia is a genus of about 30 species of trees native throughout most of the temperate Northern Hemisphere. The greatest species diversity is found in Asia, and the genus also occurs in Europe and eastern North America, but not western North America...

 scattered among the conifers, and there is usually a gradual transition into a temperate mixed forest, such as the Eastern forest-boreal transition
Eastern forest-boreal transition
The Eastern forest-boreal transition is a temperate broadleaf and mixed forests ecoregion of North America, mostly in eastern Canada.-Setting:...

 of eastern Canada. In the interior of the continents with the driest climate, 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 with mossy ground cover. In clearings in the forest, shrubs and wildflowers are common, such as the fireweed
Fireweed
Epilobium angustifolium, commonly known as Fireweed , Great Willow-herb , or Rosebay Willowherb , is a perennial herbaceous plant in the willowherb family Onagraceae...

. The other type is the lichen woodland or sparse taiga, with trees that are farther-spaced and lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

 ground cover; the latter is common in the northernmost taiga. In the northernmost taiga the forest cover is not only more sparse, but often stunted in growth form; moreover, ice pruned
Ice pruning
Ice pruning is the natural process of selective vegetative pruning on the windward side of a plant, executed by the impact of ice and snow particles driven by wind. The process is sometimes termed snow pruning...

 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 (north boreal) or 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, such as maple, elm and oak. This southern boreal forest has the longest and warmest growing season of the biome, and in some regions (including Scandinavia, Finland and western Russia) this subzone is commonly used for agricultural purposes. The boreal forest is home to many types of berries; some are confined to the southern and middle closed boreal forest (such as raspberry
Raspberry
The raspberry or hindberry is the edible fruit of a multitude of plant species in the genus Rubus, most of which are in the subgenus Idaeobatus; the name also applies to these plants themselves...

), others grow in most areas of the taiga (such as cranberry
Cranberry
Cranberries are a group of evergreen dwarf shrubs or trailing vines in the subgenus Oxycoccus of the genus Vaccinium. In some methods of classification, Oxycoccus is regarded as a genus in its own right...

 and cloudberry
Cloudberry
Rubus chamaemorus is a rhizomatous herb native to alpine and arctic tundra and boreal forest, producing amber-colored edible fruit similar to the raspberry or blackberry...

), and some can grow in both the taiga and the low arctic (southern part of) tundra (such as bilberry
Bilberry
Bilberry is any of several species of low-growing shrubs in the genus Vaccinium , bearing edible berries. The species most often referred to is Vaccinium myrtillus L., but there are several other closely related species....

 and lingonberry).

The forests of the taiga are largely coniferous
Pinophyta
The conifers, division Pinophyta, also known as division Coniferophyta or Coniferae, are one of 13 or 14 division level taxa within the Kingdom Plantae. Pinophytes are gymnosperms. They are cone-bearing seed plants with vascular tissue; all extant conifers are woody plants, the great majority being...

, dominated by larch
Larch
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...

, spruce
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 regions of the earth. Spruces are large trees, from tall when mature, and can be distinguished by their whorled branches and conical...

, fir
Fir
Firs are a genus of 48–55 species of evergreen conifers in the family Pinaceae. They are found through much of North and Central America, Europe, Asia, and North Africa, occurring in mountains over most of the range...

, and pine
Pine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

. The woodland mix varies according to geography and climate so for example the Eastern Canadian forests
Eastern Canadian forests
The Eastern Canadian forests is an ecoregion of Canada as defined by the World Wildlife Fund categorization system.-Setting:This ecoregion contains a number of mountainous areas on the east coast of Canada and along the Saint Lawrence River in eastern Quebec The Eastern Canadian forests is an...

 ecoregion of the higher elevations of the Laurentian Mountains
Laurentian mountains
The Laurentian Mountains are a mountain range in southern Quebec, Canada, north of the St. Lawrence River and Ottawa River, rising to a highest point of 1166 metres at Mont Raoul Blanchard, north east of Quebec City in the Reserve Faunique des Laurentides. The Gatineau, L'Assomption, Lièvre,...

 and the northern Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...

 in Canada is dominated by balsam fir Abies balsamea, while further north the Eastern Canadian Shield taiga
Eastern Canadian Shield taiga
The Eastern Canadian Shield taiga is an ecoregion of Canada as defined by the World Wildlife Fund categorization system.-Setting:Located in northeastern Canada, this ecoregion covers a large part of northern Quebec and most of Labrador, reaching from Hudson Bay and James Bay in the west, across to...

 of northern Quebec and Labrador is notably black spruce Picea mariana and tamarack larch Larix laricina.

Evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...

 species in the taiga (spruce, fir, and pine) have a number of adaptations specifically for survival in harsh taiga winters, although larch, the most cold-tolerant of all trees, is deciduous
Deciduous
Deciduous means "falling off at maturity" or "tending to fall off", and is typically used in reference to trees or shrubs that lose their leaves seasonally, and to the shedding of other plant structures such as petals after flowering or fruit when ripe...

. Taiga trees tend to have shallow roots to take advantage of the thin soils, while many of them seasonally alter their biochemistry
Biochemistry
Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

 to make them more resistant to freezing, called "hardening". 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
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...

. 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
Transpiration
Transpiration is a process similar to evaporation. It is a part of the water cycle, and it is the loss of water vapor from parts of plants , especially in leaves but also in stems, flowers and roots. Leaf surfaces are dotted with openings which are collectively called stomata, and in most plants...

 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.
Although the taiga is dominated by coniferous forests, some broadleaf trees
Flowering plant
The flowering plants , also known as Angiospermae or Magnoliophyta, are the most diverse group of land plants. Angiosperms are seed-producing plants like the gymnosperms and can be distinguished from the gymnosperms by a series of synapomorphies...

 also occur, notably birch
Birch
Birch is a tree or shrub of the genus Betula , in the family Betulaceae, closely related to the beech/oak family, Fagaceae. The Betula genus contains 30–60 known taxa...

, aspen
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...

, willow
Willow
Willows, sallows, and osiers form the genus Salix, around 400 species of deciduous trees and shrubs, found primarily on moist soils in cold and temperate regions of the Northern Hemisphere...

, and rowan
Rowan
The rowans or mountain-ashes are shrubs or small trees in genus Sorbus of family Rosaceae. They are native throughout the cool temperate regions of the Northern Hemisphere, with the highest species diversity in the mountains of western China and the Himalaya, where numerous apomictic microspecies...

. Many smaller herbaceous
Herbaceous
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...

 plants grow closer to the ground. Periodic stand-replacing wildfire
Wildfire
A wildfire is any uncontrolled fire in combustible vegetation that occurs in the countryside or a wilderness area. Other names such as brush fire, bushfire, forest fire, desert fire, grass fire, hill fire, squirrel fire, vegetation fire, veldfire, and wilkjjofire may be used to describe the same...

s (with return times of between 20–200 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
Jack Pine
Jack pine is a North American pine with its native range in Canada east of the Rocky Mountains from Northwest Territories to Nova Scotia, and the northeast of the United States from Minnesota to Maine, with the southernmost part of the range just into northwest Indiana...

 have cones which only open to release their seed after a fire, dispersing their seeds onto the newly cleared ground. Grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...

es grow wherever they can find a patch of sun, and moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...

es and lichen
Lichen
Lichens are composite organisms consisting of a symbiotic organism composed of a fungus with a photosynthetic partner , usually either a green alga or cyanobacterium...

s thrive on the damp ground and on the sides of tree trunks. In comparison with other biomes, however, the taiga has low biological diversity.

Coniferous trees are the dominant plants of the taiga biome. A 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
Russian Far East
Russian Far East is a term that refers to the Russian part of the Far East, i.e., extreme east parts of Russia, between Lake Baikal in Eastern Siberia and the Pacific Ocean...

 and Mongolia
Mongolia
Mongolia is a landlocked country in East and Central Asia. It is bordered by Russia to the north and China to the south, east and west. Although Mongolia does not share a border with Kazakhstan, its western-most point is only from Kazakhstan's eastern tip. Ulan Bator, the capital and largest...

 is dominated by larch
Larch
Larches are conifers in the genus Larix, in the family Pinaceae. Growing from 15 to 50m tall, they are native to much of the cooler temperate northern hemisphere, on lowlands in the north and high on mountains further south...

.

Wildlife



The boreal forest, or taiga, supports a large range of animals. Canada's boreal forest includes 85 species of mammals, 130 species of fish, and an estimated 32,000 species of insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s. Insects play a critical role as pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...

s, decomposers, and as a part of the food web. Many nesting birds rely on them for food. The cold winters and short summers make the taiga a challenging biome for reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...

s and amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...

s, which depend on environmental conditions to regulate their body temperatures, and there are only a few species in the boreal forest. Some hibernate underground in winter.

The taiga is home to a number of large herbivorous
Herbivore
Herbivores are organisms that are anatomically and physiologically adapted to eat plant-based foods. Herbivory is a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria. More generally, organisms that feed on autotrophs in...

 mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...

s, such as moose
Moose
The moose or Eurasian elk is the largest extant species in the deer family. Moose are distinguished by the palmate antlers of the males; other members of the family have antlers with a dendritic configuration...

 and reindeer
Reindeer
The reindeer , also known as the caribou in North America, is a deer from the Arctic and Subarctic, including both resident and migratory populations. While overall widespread and numerous, some of its subspecies are rare and one has already gone extinct.Reindeer vary considerably in color and size...

/caribou. Some areas of the more southern closed boreal forest also have populations of other deer species such as the elk
Elk
The Elk is the large deer, also called Cervus canadensis or wapiti, of North America and eastern Asia.Elk may also refer to:Other antlered mammals:...

 (wapiti) and roe deer
Roe Deer
The European Roe Deer , also known as the Western Roe Deer, chevreuil or just Roe Deer, is a Eurasian species of deer. It is relatively small, reddish and grey-brown, and well-adapted to cold environments. Roe Deer are widespread in Western Europe, from the Mediterranean to Scandinavia, and from...

. There is also a range of rodent
Rodent
Rodentia is an order of mammals also known as rodents, characterised by two continuously growing incisors in the upper and lower jaws which must be kept short by gnawing....

 species including beaver
Beaver
The beaver is a primarily nocturnal, large, semi-aquatic rodent. Castor includes two extant species, North American Beaver and Eurasian Beaver . Beavers are known for building dams, canals, and lodges . They are the second-largest rodent in the world...

, squirrel
Squirrel
Squirrels belong to a large family of small or medium-sized rodents called the Sciuridae. The family includes tree squirrels, ground squirrels, chipmunks, marmots , flying squirrels, and prairie dogs. Squirrels are indigenous to the Americas, Eurasia, and Africa and have been introduced to Australia...

, mountain hare
Mountain Hare
The Mountain Hare , also known as Blue Hare, Tundra Hare, Variable Hare, White Hare, Alpine Hare and Irish Hare, is a hare, which is largely adapted to polar and mountainous habitats. It is distributed from Fennoscandia to eastern Siberia; in addition there are isolated populations in the Alps,...

, snowshoe hare
Snowshoe Hare
The Snowshoe Hare , also called the Varying Hare, or Snowshoe Rabbit, is a species of hare found in North America. It has the name "snowshoe" because of the large size of its hind feet and the marks its tail leaves. The animal's feet prevent it from sinking into the snow when it hops and walks...

, and vole
Vole
A vole is a small rodent resembling a mouse but with a stouter body, a shorter hairy tail, a slightly rounder head, smaller ears and eyes, and differently formed molars . There are approximately 155 species of voles. They are sometimes known as meadow mice or field mice in North America...

. These species have evolved to survive the harsh winters in their native ranges. Some larger mammals, such as bear
Bear
Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...

s, eat heartily during the summer in order to gain weight, and then go into hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...

 during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold.

A number of wildlife species threatened or endangered with extinction can be found in the Canadian boreal forest, including woodland caribou, American black bear
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...

, grizzly bear
Grizzly Bear
The grizzly bear , also known as the silvertip bear, the grizzly, or the North American brown bear, is a subspecies of brown bear that generally lives in the uplands of western North America...

, and wolverine
Wolverine
The wolverine, pronounced , Gulo gulo , also referred to as glutton, carcajou, skunk bear, or quickhatch, is the largest land-dwelling species of the family Mustelidae . It is a stocky and muscular carnivore, more closely resembling a small bear than other mustelids...

. Habitat loss, mainly due to logging, is the primary cause of decline for these species.

Due to the climate, carnivorous
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...

 diets are an inefficient means of obtaining energy; energy is limited, and most energy is lost between trophic level
Trophic level
The trophic level of an organism is the position it occupies in a food chain. The word trophic derives from the Greek τροφή referring to food or feeding. A food chain represents a succession of organisms that eat another organism and are, in turn, eaten themselves. The number of steps an organism...

s. Predatory birds (owl
Owl
Owls are a group of birds that belong to the order Strigiformes, constituting 200 bird of prey species. Most are solitary and nocturnal, with some exceptions . Owls hunt mostly small mammals, insects, and other birds, although a few species specialize in hunting fish...

s and eagle
Eagle
Eagles are members of the bird family Accipitridae, and belong to several genera which are not necessarily closely related to each other. Most of the more than 60 species occur in Eurasia and Africa. Outside this area, just two species can be found in the United States and Canada, nine more in...

s) and other smaller carnivores, including fox
Fox
Fox is a common name for many species of omnivorous mammals belonging to the Canidae family. Foxes are small to medium-sized canids , characterized by possessing a long narrow snout, and a bushy tail .Members of about 37 species are referred to as foxes, of which only 12 species actually belong to...

es and weasel
Weasel
Weasels are mammals forming the genus Mustela of the Mustelidae family. They are small, active predators, long and slender with short legs....

s, feed on the rodents. Larger carnivores, such as lynx
Lynx
A lynx is any of the four Lynx genus species of medium-sized wildcats. The name "lynx" originated in Middle English via Latin from Greek word "λύγξ", derived from the Indo-European root "*leuk-", meaning "light, brightness", in reference to the luminescence of its reflective eyes...

 and wolves, prey on the larger animals. Omnivore
Omnivore
Omnivores are species that eat both plants and animals as their primary food source...

s, such as bear
Bear
Bears are mammals of the family Ursidae. Bears are classified as caniforms, or doglike carnivorans, with the pinnipeds being their closest living relatives. Although there are only eight living species of bear, they are widespread, appearing in a wide variety of habitats throughout the Northern...

s and raccoon
Raccoon
Procyon is a genus of nocturnal mammals, comprising three species commonly known as raccoons, in the family Procyonidae. The most familiar species, the common raccoon , is often known simply as "the" raccoon, as the two other raccoon species in the genus are native only to the tropics and are...

s are fairly common, sometimes picking through human garbage.

More than 300 species of bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

s have their nest
Nest
A nest is a place of refuge to hold an animal's eggs or provide a place to live or raise offspring. They are usually made of some organic material such as twigs, grass, and leaves; or may simply be a depression in the ground, or a hole in a tree, rock or building...

ing grounds in the taiga. Siberian Thrush
Siberian Thrush
The Siberian Thrush, Zoothera sibirica, is a member of the Thrush family Turdidae.It breeds in taiga in Siberia. It is strongly migratory, with most birds moving to southeastern Asia during the winter. It is a very rare vagrant to western Europe. It is very secretive.The Siberian Thrush is similar...

, White-throated Sparrow
White-throated Sparrow
The White-throated Sparrow is a passerine bird of the American sparrow family Emberizidae.-Description:The White-throated Sparrow is a passerine bird of the American sparrow family Emberizidae...

, and Black-throated Green Warbler
Black-throated Green Warbler
The Black-throated Green Warbler, Setophaga virens, is a small songbird of the New World warbler family.It is 12 cm long and weighs 9 g, and has an olive-green crown, a yellow face with olive markings, a thin pointed bill, white wing bars, an olive-green back and pale underparts with...

 migrate
Bird migration
Bird migration is the regular seasonal journey undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. Sometimes, journeys are not termed "true migration" because they are irregular or in only one direction...

 to this habitat
Habitat (ecology)
A habitat is an ecological or environmental area that is inhabited by a particular species of animal, plant or other type of organism...

 to take advantage of the long summer days and abundance of insect
Insect
Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s 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
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...

-feeding or large raptor
Bird of prey
Birds of prey are birds that hunt for food primarily on the wing, using their keen senses, especially vision. They are defined as birds that primarily hunt vertebrates, including other birds. Their talons and beaks tend to be relatively large, powerful and adapted for tearing and/or piercing flesh....

s that can take live mammal prey, including Golden Eagle
Golden Eagle
The Golden Eagle is one of the best known birds of prey in the Northern Hemisphere. Like all eagles, it belongs to the family Accipitridae. Once widespread across the Holarctic, it has disappeared from many of the more heavily populated areas...

, Rough-legged Buzzard
Rough-legged Buzzard
The Rough-legged Buzzard , called the Rough-legged Hawk in North America, is a medium-large bird of prey. It is found in Arctic and Subarctic regions of North America and Eurasia during the breeding season and migrates south for the winter.The species exhibits a wide variety of plumage patterns...

 (also known as the Rough-legged Hawk), and Raven
Raven
Raven is the common name given to several larger-bodied members of the genus Corvus—but in Europe and North America the Common Raven is normally implied...

, or else seed-eating birds, including several species of grouse
Grouse
Grouse are a group of birds from the order Galliformes. They are sometimes considered a family Tetraonidae, though the American Ornithologists' Union and many others include grouse as a subfamily Tetraoninae in the family Phasianidae...

 and crossbill
Crossbill
The crossbill is a bird in the finch family . The three to five species are all classified in the genus Loxia. These birds are characterised by the mandibles crossing at their tips, which gives the group its English name...

s.

Human activities


Large areas of Siberia
Siberia
Siberia is an extensive region constituting almost all of Northern Asia. Comprising the central and eastern portion of the Russian Federation, it was part of the Soviet Union from its beginning, as its predecessor states, the Tsardom of Russia and the Russian Empire, conquered it during the 16th...

’s taiga have been harvested for lumber since the collapse of the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

. In Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

, eight percent of the boreal forest is protected from development, the provincial government allows forest management to occur on Crown land under rigorous constraints. The main forestry practice in the boreal forest of Canada is clearcutting
Clearcutting
Clearcutting, or clearfelling, is a controversial forestry/logging practice in which most or all trees in an area are uniformly cut down. Clearcutting, along with shelterwood and seed tree harvests, is used by foresters to create certain types of forest ecosystems and to promote select species that...

, which involves cutting down most of the trees in a given area, then replanting the forest as a monocrop (one species of tree) the following season. Industry officials claim that this process emulates the natural effects of a forest fire, which they claim clearcutting suppresses, protecting infrastructure, communities and roads. However, from an ecological perspective, this is a falsehood, for several reasons, including: a) Removing most of the trees in a given area is usually done using large machines which disrupt the soil greatly, and the dramatic diminution of ground cover permits large-scale erosion and avalanches, which further damage the habitat and sometimes endangers infrastructure, roads, and communities. b) Clearcutting removes most of the biomass from an area, and the various macro and micro-nutrients it contains. This sudden decrease in nutrients in an area contrasts with a forest fire, which returns most of the nutrients to the soil. c) Forest fires leave standing snags, and leave patches of unburned trees. This helps preserve structure and micro-habitats within the area, whereas clearcutting destroys most of these habitats. In the past, clearcuts upwards of 110 km² have been recorded in the Canadian boreal forest. However, today 80% of clearcuts are less than 260 hectares(2.6 square km). Some of the products from logged boreal forests include toilet paper
Toilet paper
Toilet paper is a soft paper product used to maintain personal hygiene after human defecation or urination. However, it can also be used for other purposes such as blowing one's nose when one has a cold or absorbing common spills around the house, although paper towels are more used for the latter...

, copy paper, newsprint, and lumber. More than 90% of boreal forest products from Canada are exported for consumption and processing in the United States, however with the recession and fewer US homes being built that has changed. Some of the larger cities situated in this biome are Murmansk
Murmansk
Murmansk is a city and the administrative center of Murmansk Oblast, Russia. It serves as a seaport and is located in the extreme northwest part of Russia, on the Kola Bay, from the Barents Sea on the northern shore of the Kola Peninsula, not far from Russia's borders with Norway and Finland...

, Arkhangelsk
Arkhangelsk
Arkhangelsk , formerly known as Archangel in English, is a city and the administrative center of Arkhangelsk Oblast, Russia. It lies on both banks of the Northern Dvina River near its exit into the White Sea in the north of European Russia. The city spreads for over along the banks of the river...

, Yakutsk
Yakutsk
With a subarctic climate , Yakutsk is the coldest city, though not the coldest inhabited place, on Earth. Average monthly temperatures range from in July to in January. The coldest temperatures ever recorded on the planet outside Antarctica occurred in the basin of the Yana River to the northeast...

, Anchorage, Yellowknife, Tromsø
Tromsø
Tromsø is a city and municipality in Troms county, Norway. The administrative centre of the municipality is the city of Tromsø.Tromsø city is the ninth largest urban area in Norway by population, and the seventh largest city in Norway by population...

, Luleå
Luleå
- Transportation :Local buses are run by .A passenger train service is available from Luleå Centralstation on Sweden's national SJ railway service northbound to Narvik on the Norwegian coast, or southbound to Stockholm. See Rail transport in Sweden....

, and Oulu
Oulu
Oulu is a city and municipality of inhabitants in the region of Northern Ostrobothnia, in Finland. It is the most populous city in Northern Finland and the sixth most populous city in the country. It is one of the northernmost larger cities in the world....

.

Most companies that harvest in Canadian forests are certified by an independent third party agency such as the Forest Stewardship Council (FSC), Sustainable Forests Initiative (SFI), or the Canadian Standards Association (CSA). While the certification process differs between these groups, all of them include forest stewardship, respect for aboriginal peoples, compliance with local, provincial or national environmental laws, forest worker safety, education and training, and other environmental, business, and social requirements. The prompt renewal of all harvest sites by planting or natural renewal is also required.

Climate change


The zone of latitude occupied by the boreal forest has experienced some of the greatest temperature increases on Earth, especially during the last quarter of the twentieth century. Winter temperatures have increased more than summer temperatures. The number of days with extremely cold temperatures (e.g., −20 to −40 °C) has decreased irregularly but systematically in nearly all the boreal region, allowing better survival for tree-damaging insects. In summer, the daily low temperature has increased more than the daily high temperature. In Fairbanks, Alaska, the length of the frost-free season has increased from 60–90 days in the early twentieth century to about 120 days a century later. Summer warming has been shown to increased water stress and reduce tree growth in dry areas of the southern boreal forest in central Alaska, western Canada and portions of far eastern Russia. Precipitation is relatively abundant in Scandinavia, Finland, northwest Russia and eastern Canada, where warmer summers accelerate tree growth. As a consequence of this warming trend, the warmer parts of the boreal forests are susceptible to replacement by grassland, parkland or temperate forest.
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.

Insects


Recent years have seen outbreaks of insect pests in forest-destroying plagues: the spruce-bark beetle (Dendroctonus rufipennis
Dendroctonus rufipennis
The Spruce Beetle is a species of bark beetle native to British Columbia, Newfoundland and Labrador, Nova Scotia, Ontario, Quebec, the Yukon, and Maine. They are known to destroy forests of spruce trees including Englemann, White, Sitka, and Colorado blue spruce...

) in the Yukon Territory, Canada, and Alaska; the aspen
Aspen
Populus section Populus, of the Populus genus, includes the aspen trees and the white poplar Populus alba. The five typical aspens are all native to cold regions with cool summers, in the north of the Northern Hemisphere, extending south at high altitudes in the mountains. The White Poplar, by...

-leaf miner; the larch sawfly
Larch sawfly
The larch sawfly is a species of sawfly. The adult sawfly resembles a black wasp, is about ½ inch in length with a thick waist and has brown to orangish markings on the abdomen. Larvae have black heads, gray-green bodies with white undersides, and are about 15–18 mm long when full grown...

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

Protection


Many nations are taking direct steps to protect the ecology of the taiga by prohibiting logging, mining, oil and gas production, and other forms of development. In February 2010 the Canadian government established 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.
The taiga stores enormous quantities of carbon
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...

, possibly more than the temperate and tropical forests combined, much of it in peatland.

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. The phenomenon of wildfire by lightning strike is the primary determinant of understory vegetation and because of this, it is considered to be predominate driving force behind community and ecosystem properties in the lichen woodland. 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. 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 a 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. 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 [lichen woodlands] persistence, along with their previous moss forest histories and current occurrence adjacent to closed moss forests, indicate that they are an alternative stable state
Alternative stable state
In ecology, the theory of alternative stable states predicts that ecosystems can exist under multiple “states” . These alternative states are non-transitory and therefore considered stable over ecologically-relevant timescales...

 to the spruce–moss forests”.

See also


  • Birds of North American boreal forests
    Birds of North American boreal forests
    The boreal forest or taiga of the North American continent stretches through a majority of Canada and most of central Alaska, extending spottily into the beginning of the Rocky Mountain range in Northern Montana and into New England and the Adirondack Mountains of New York...

  • Boreal Forest Conservation Framework
    Boreal Forest Conservation Framework
    The Boreal Forest Conservation Framework, was adopted December 1, 2003 to protect the Canadian boreal forest. The vision set out in the Framework is "to sustain the ecological and cultural integrity of the Canadian boreal region, in perpetuity." Its goal is to conserve the boreal region by:...

  • Boreal forest of Canada
    Boreal forest of Canada
    Canada's boreal forest comprises about one third of the circumpolar boreal forest that rings the northern hemisphere, mostly north of the 50th parallel. Other countries with boreal forest include Russia, which contains the majority, and the Scandinavian and Nordic countries . The boreal region in...

  • Intact forest landscape
    Intact forest landscape
    An Intact Forest Landscape—IFL is an unbroken natural landscape of a forest ecosystem and its habitat—plant community components, in a current extant forest zone...

  • Scandinavian and Russian taiga
    Scandinavian and Russian taiga
    The Scandinavian and Russian taiga is an ecoregion within the Taiga and Boreal forests Biome as defined by the WWF classification...

  • Success of fire suppression in northern forests
  • Taiga Rescue Network (TRN)
    Taiga Rescue Network
    Taiga Rescue Network is an international network of more than 200 non-governmental organizations, indigenous peoples and individuals working to defend the world's boreal forests, also known as Taiga. TRN was established in 1992 to give a voice to support, link and publicize local struggles...


External links