The taiga is found throughout the high northern latitudes, just below the tundra, and just above the steppes.

Taiga (IPA pronunciation: /'taɪgə/ or /taɪ 'ga/, from Mongolian) is a biome characterized by coniferous forests. Covering most of inland Alaska, Canada, Sweden, Finland, inland Norway, northern Kazakhstan and Russia (especially Siberia), as well as parts of the extreme northern continental United States, the taiga is the world's largest terrestrial biome. In Canada, boreal forest is the term used to refer to the southern part of this biome, while "taiga" is used to describe the more barren northern areas south of the Arctic tree-line. Image File history File links Download high resolution version (1262x628, 28 KB) Based on map located on commons by user Vzb83. ... Image File history File links Download high resolution version (1262x628, 28 KB) Based on map located on commons by user Vzb83. ... Latitude, usually denoted symbolically by the Greek letter φ, gives the location of a place on Earth north or south of the Equator. ... In physical geography, tundra is an area where the tree growth is hindered by low temperatures and short growing seasons. ... A steppe in Western Kazakhstan in early spring In physical geography, a steppe (Russian: - step, Ukrainian: - step, Kazakh: - dala), pronounced in English as step, is a plain without trees (apart from those near rivers and lakes); it is similar to a prairie, although a prairie is generally considered as being... For information on how to read IPA transcriptions of English words see here. ... In ecology, a biome is a major regional group of distinctive plant and animal communities best adapted to the regions physical natural environment, latitude, altitude, and terrain. ... Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, are one of 13 or 14 division level taxa within the Kingdom Plantae. ... Official language(s) English Capital Juneau Largest city Anchorage Area  Ranked 1st  - Total 663,267 sq mi (1,717,855 km²)  - Width 808 miles (1,300 km)  - Length 1,479 miles (2,380 km)  - % water 13. ... Siberian Federal District (dark red) and the broadest definition of Siberia (red) Udachnaya pipe Siberia (Russian: , Sibir; Tatar: ) is a vast region of Russia constituting almost all of Northern Asia. ... Depending on usage, the term continental United States can refer to either: the 48 contiguous states plus the District of Columbia; or the 48 contiguous states plus the District of Columbia and Alaska. ... A sign along the Dalton Highway marking the location of the Arctic Circle The Arctic Circle is one of the five major circles of latitude that mark maps of the Earth. ... In this view of an alpine tree-line, the distant line looks particularly sharp. ...

Since North America and Eurasia were recently connected by the Bering land bridge, a number of animal and plant species (more animals than plants) were able to colonise both continents and are distributed throughout the taiga biome. 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 aspen; mostly in areas escaping the most extreme winter cold. However, the deciduous Larch is coping with the coldest winters on the northern hemisphere in eastern Siberia. The southernmost part of the taiga also have trees like oak, maple and elm scattered among the conifers. World map showing North America A satellite composite image of North America. ... Eurasia African-Eurasian aspect of Earth Eurasia is the landmass composed of Europe and Asia. ... Nautical chart of Bering Strait, site of former land bridge between Asia and North America The Bering land bridge, also known as Beringia, was a land bridge roughly 1600 km (1000 miles) north to south at its greatest extent, which joined present-day Alaska and eastern Siberia at various times... Species About 12; see text Siberian larch Male (above) and female (below right) cones of Japanese Larch emerging in spring Larches are conifers in the genus Larix, in the family Pinaceae. ...

Climate and geography

White Spruce taiga, Denali Highway, Alaska Range, Alaska.

The taiga biome has a harsh continental climate with a very large temperature range between summer and winter, classified as "Dfc" or "Dfb" in the Köppen climate classification scheme. Aside from the tundra and permanent ice caps, it is the coldest biome on Earth. High latitudes mean that, for much of the year the sun does not rise far above the horizon; winters last at least 5-6 months, with average temperatures below freezing. Temperatures vary from -50 °C to 30 °C throughout the whole year, with 8 or more months of temperatures averaging below 10 °C. The summers, while short, are generally warm and humid. In general, taiga grows north to the 10 °C July isotherm, occasionally to the 9 °C July isotherm (Arno & Hammerly 1984, Arno et al. 1995). The southern limit is more variable, depending on rainfall; taiga may be replaced by open steppe woodland 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 and adjacent northern Manchuria) 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, Jezo Spruce and Manchurian Fir, and merges gradually into mixed temperate forest, or more locally (on the Pacific Ocean coasts of North America and Asia) into coniferous temperate rainforests. Image File history File links Picea_glauca_taiga. ... Image File history File links Picea_glauca_taiga. ... Binomial name Picea glauca (Moench) Voss The White Spruce (Picea glauca) is a medium-sized evergreen tree growing to 15-30 m tall, rarely to 40 m tall, and with a trunk diameter of up to 1 m. ... The Köppen climate classification is one of the most widely used climate classification systems. ... The Köppen climate classification is one of the most widely used climate classification systems. ... In physical geography, tundra is an area where the tree growth is hindered by low temperatures and short growing seasons. ... The Sun is the star of our solar system. ... An isotherm is a line of equal or constant temperature on a graph, plot, or map; an isopleth of temperature. ... A steppe in Western Kazakhstan in early spring In physical geography, a steppe (Russian: - step, Ukrainian: - step, Kazakh: - dala), pronounced in English as step, is a plain without trees (apart from those near rivers and lakes); it is similar to a prairie, although a prairie is generally considered as being... Siberian Federal District (dark red) and the broadest definition of Siberia (red) Udachnaya pipe Siberia (Russian: , Sibir; Tatar: ) is a vast region of Russia constituting almost all of Northern Asia. ... Manchuria (Manchu: Manju; Traditional Chinese: 滿洲; Simplified Chinese: 满洲; pinyin: MÇŽnzhōu, Russian: ) is a vast territorial region in northeast Asia. ... Binomial name Pinus koraiensis The Korean Pine (Pinus koraiensis; family Pinaceae) is a species of pine tree that occurs in eastern Asia, in Manchuria in northeast China, Primorsky Krai and Khabarovsk Krai in the far east of Russia, Korea and central Japan. ... Binomial name Picea jezoensis (Siebold & Zucc. ... Binomial name Abies holophylla Maxim. ... Temperate broadleaf and mixed forests are a temperate and humid biome. ... Temperate rain forests are coniferous or broadleaf forests that occur in the mid-latitudes in areas of high rainfall. ...

The taiga experiences relatively low precipitation throughout the year (200-750 mm annually), primarily as rain during the summer months, but also as fog and snow; as evaporation is also low for most of the year, precipitation exceeds evaporation and is sufficient for dense vegetation growth. Snow may remain on the ground for as long as nine months in the northernmost extensions of the taiga ecozone (Sayre, 16).

Much of the area currently classified as taiga was recently glaciated. As the glaciers receded, they left depressions in the topography that have since filled with water, creating lakes and bogs (especially muskeg soil), found throughout the taiga. The Wisconsin (in North America), Weichsel (in Scandinavia), Devensian (in the British Isles), Midlandian (in Ireland) and Würm glaciation (in the Alps) are the most recent glaciations of the Pleistocene, which ended around 10,000 BC. The general glacial advance began about 70,000 BC, and reached its maximum... A kettle is a landform feature in glaciated terrain. ... Muskeg is a soil type (also a peatland or wetland type called a bog) common in arctic and boreal areas. ...

Soils

Taiga soil tends to be young and nutrient-poor; it lacks the deep, organically-enriched profile present in temperate deciduous forests (Sayre, 19). The thinness of the soil is due largely to the cold; it hinders the development of soil, as well as the ease with which plants can use its nutrients (Sayre, 19). Fallen leaves and moss can remain on the forest floor for a long time in the cool, moist climate, which limits their organic contribution to the soil; acids from evergreen needles further leach the soil, creating spodosol (Sayre, 19-20). Since the soil is acidic, the forest floor has only lichens and some mosses growing on it. Loess field in Germany Soil horizons are formed by combined biological, chemical and physical alterations. ... A soil profile is a cross section through the soil which reveals its horizons (layers). ... An acid (often represented by the generic formula HA) is traditionally considered any chemical compound that, when dissolved in water, gives a solution with a pH of less than 7. ... Podsol (also spelled Podzol, or known as Spodosol) is the typical soil of coniferous, or Boreal forests. ... For other things named Lichen, see: Lichen (disambiguation). ... Subclasses Sphagnidae Andreaeidae Tetraphidae Polytrichidae Archidiidae Buxbaumiidae Bryidae Mosses are small, soft plants that are typically 1-10 cm tall, occasionally more. ...

Flora

Black Spruce taiga, Copper River, Alaska.

There are two major types of taiga, closed forest, consisting of many closely-spaced trees with mossy ground cover, and lichen woodland, with trees that are farther-spaced and lichen ground cover; the latter is more common in the northernmost taiga (Sayre, 12-3). Image File history File links Picea_mariana_taiga. ... Image File history File links Picea_mariana_taiga. ... Binomial name Picea mariana The Black Spruce (Picea mariana) is a common coniferous tree in North America. ... Lichenes from Ernst Haeckels Artforms of Nature, 1904 Crustose and foliose lichens on a wall A foliose lichen on basalt. ...

The forests of the taiga are largely coniferous, dominated by larch, spruce, fir, and pine. Evergreen species in the taiga (spruce, fir, and pine) have a number of adaptations specifically for survival in harsh taiga winters, though larch, the most cold-tolerant of all trees, 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 (Sayre, 23). Orders & Families Cordaitales † Pinales   Pinaceae - Pine family   Araucariaceae - Araucaria family   Podocarpaceae - Yellow-wood family   Sciadopityaceae - Umbrella-pine family   Cupressaceae - Cypress family   Cephalotaxaceae - Plum-yew family   Taxaceae - Yew family Vojnovskyales † Voltziales † The conifers, division Pinophyta, also known as division Coniferae, are one of 13 or 14 division level taxa within the... Species About 12; see text Siberian larch Male (above) and female (below right) cones of Japanese Larch emerging in spring Larches are conifers in the genus Larix, in the family Pinaceae. ... Species About 35; see text. ... FIR may stand for: finite impulse response (a property of some digital filters) far infrared, i. ... Species About 115 species Pines are coniferous trees of the genus Pinus, in the family Pinaceae. ... A Silver Fir shoot showing three successive years of retained leaves In botany, an evergreen plant is a plant which retains its leaves year-round, with each leaf persisting for more than 12 months. ... Deciduous means temporary or tending to fall off (deriving from the Latin word decidere, to fall off). ... Biochemistry is the study of the chemical processes and transformations in living organisms. ...

Because the sun is low in the horizon for most of the year, it is difficult for plants to generate energy from photosynthesis. Pine and spruce 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. The leaf is the primary site of photosynthesis in plants. ... Transpiration is the evaporation of water from aerial parts of plants, especially leaves but also stems, flowers and fruits. ...

Although the taiga is dominated by coniferous forests, some broadleaf trees also occur, notably birch, aspen, willow, and rowan. Many smaller herbaceous plants grow closer to the ground. Periodic stand-replacing wildfires (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 have cones which only open to release their seed after a fire, dispersing their seeds onto the newly cleared ground. Grasses grow wherever they can find a patch of sun, and mosses and lichens thrive on the damp ground and on the sides of tree trunks. In comparison with other biomes, however, the taiga has a low biological diversity. It has been suggested that Angiospermae, and Anthophyta be merged into this article or section. ... Species Many species; see text and classification Birch is the name of any tree of the genus Betula, in the family Betulaceae, closely related to the beech/oak family, Fagaceae. ... Species Populus adenopoda Populus alba Populus grandidentata Populus sieboldii Populus tremula Populus tremuloides Aspens are trees of the willow family and comprise a section of the poplar genus, Populus sect. ... Species About 350, including: Salix acutifolia - Violet Willow Salix alaxensis - Alaska Willow Salix alba - White Willow Salix alpina - Alpine Willow Salix amygdaloides - Peachleaf Willow Salix arbuscula - Mountain Willow Salix arbusculoides - Littletree Willow Salix arctica - Arctic Willow Salix atrocinerea Salix aurita - Eared Willow Salix babylonica - Peking Willow Salix bakko Salix barrattiana... Species The rowans are plants of the Family Rosaceae, in the Genus Sorbus, Subgenus Sorbus. ... This article is about the plants used in cooking and medicine. ... {{alternateuses}} The Old Fire burning in the San Bernardino Mountains (image taken from the International Space Station) A wildfire, also known as a forest fire, vegetation fire, grass fire, brush fire, peat fire (gambut in Indonesia), bushfire (in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland... Binomial name Pinus banksiana Lamb. ... An area of grass-like plants Grass generally describes a monocotyledonous green plant in the family Poaceae, botanically regarded as true grasses. ... Subclasses Sphagnidae Andreaeidae Tetraphidae Polytrichidae Archidiidae Buxbaumiidae Bryidae Mosses are small, soft plants that are typically 1-10 cm tall, occasionally more. ... Lichenes from Ernst Haeckels Artforms of Nature, 1904 Crustose and foliose lichens on a wall A foliose lichen on basalt. ...

Fauna

The taiga is home to a number of large herbivorous mammals and smaller rodents. These animals have also adapted to survive the harsh climate. Some of the larger mammals, such as bears, eat during the summer in order to gain weight and then go into hibernation during the winter. Other animals have adapted layers of fur or feathers to insulate them from the cold. A deer and two fawns feeding on some foliage A herbivore is often defined as any organism that eats only plants[1]. By that definition, many fungi, some bacteria, many animals, about 1% of flowering plants and some protists can be considered herbivores. ... Orders Multituberculata (extinct) Palaeoryctoides (extinct) Triconodonta (extinct) Subclass Australosphenida Ausktribosphenida Monotremata Subclass Eutheria (excludes extinct ancestors) Afrosoricida Anagaloidea (extinct) Arctostylopida (extinct) Artiodactyla Carnivora Cetacea Chiroptera Cimolesta (extinct) Cingulata Creodonta (extinct) Condylarthra (extinct) Dermoptera Desmostylia (extinct) Dinocerata (extinct) Embrithopoda (extinct) Hyracoidea Insectivora Lagomorpha Leptictida (extinct) Litopterna (extinct) Macroscelidea Mesonychia (extinct) Notoungulata... Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia is an order of mammals also known as rodents. ... Genera Ailuropoda Ailurus Helarctos Melursus Ursus Tremarctos Arctodus (extinct) A bear is a large mammal in the family Ursidae of the order Carnivora. ... Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate, to conserve energy, especially during winter. ...

Due to the climate, carnivorous diets are an inefficient means of obtaining energy; energy is limited, and most energy is lost between trophic levels. However, predatory birds (owls and eagles) and other smaller carnivores, including foxes and weasels, feed on the rodents. Larger carnivores, such as lynxes and wolves, prey on the larger animals. Omnivores, such as bears and raccoons are fairly common, sometimes picking through human garbage. This tigers sharp teeth and strong jaws are the classical physical traits expected from carnivorous mammalian predators A carnivore (IPA: ), meaning meat eater (Latin carne meaning flesh and vorare meaning to devour), is an animal that eats a diet consisting mainly of meat, whether it comes from live animals... In ecology, the trophic level is the position that an organism occupies in a food chain - what it eats, and what eats it. ... This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ... Families Strigidae Tytonidae The owl is a solitary, mainly nocturnal bird of prey. ... // This article is about the bird. ... A fox is a member of any of 27 species of small omnivorous canids. ... Species Mustela africana Mustela altaica Mustela erminea Mustela eversmannii Mustela felipei Mustela frenata Mustela kathiah Mustela lutreola Mustela lutreolina Mustela nigripes Mustela nivalis Mustela nudipes Mustela putorius Mustela sibirica Mustela strigidorsa Mustela vison Weasels are mammals in the genus Mustela of the Mustelidae family. ... poopTaxobox | color = pink | name = Lynx | image = lynx-canadensis. ... Wolf Wolf Man Mount Wolf Wolf Prizes Wolf Spider Wolf 424 Wolf 359 Wolf Point Wolf-herring Frank Wolf Friedrich Wolf Friedrich August Wolf Hugo Wolf Johannes Wolf Julius Wolf Max Franz Joseph Cornelius Wolf Maximilian Wolf Rudolf Wolf Thomas Wolf As Name Wolf Breidenbach Wolf Hirshorn Other The call... Pigs are omnivores. ... Genera Ailuropoda Ailurus Helarctos Melursus Ursus Tremarctos Arctodus (extinct) A bear is a large mammal in the family Ursidae of the order Carnivora. ... Type Species Procyon lotor Linnaeus, 1758 Species Procyon cancrivorus Procyon insularis Procyon lotor Raccoons are nocturnal mammals in the genus Procyon of the Procyonidae family. ...

A considerable number of birds such as Siberian Thrush, White's Thrush and Dark-throated Thrush, migrate to this habitat to take advantage of the long summer days and abundance of insects found around the numerous bogs and lakes. Of the perhaps 300 species of birds that summer in the taiga, only 30 stay for the winter (Sayre, 28). These are either carrion-feeding or large raptors that can take live mammal prey, including Golden Eagle, Rough-legged Buzzard, and Raven, or else seed-eating birds, including several species of grouse and crossbills. Orders Many - see section below. ... Binomial name Zoothera sibirica (Pallas, 1776) The Siberian Thrush, Zoothera sibirica, is a member of the Thrush family Turdidae. ... Binomial name Zoothera dauma (Latham, 1790) The Whites Thrush (Zoothera dauma) is a member of the Thrush family Turdidae. ... Binomial name Turdus ruficollis Pallas, 1776 The Dark-throated Thrush (Turdus ruficollis) is a passerine bird in the thrush family. ... Flock of Barnacle Geese during autumn migration Many species of birds undertake seasonal journeys of various lengths, a phenomenon known as Bird migration. ... Habitat (from the Latin for it inhabits) is the place where a particular species lives and grows. ... Orders See taxonomy Insects are invertebrates that are taxonomically referred to as the class Insecta. ... Titan arum For other uses, see Carrion (disambiguation). ... Look up raptor in Wiktionary, the free dictionary. ... Binomial name Aquila chrysaetos Linnaeus, 1758 World distribution of the golden eagle Light green = Nesting area Blue = Wintering area Dark green = All year distribution The Golden Eagle (Aquila chrysaetos) is one of the best known birds of prey in the Northern Hemisphere. ... Binomial name Buteo lagopus (Pontoppidan, 1763) The Rough-legged Buzzard (Buteo lagopus), called the Rough-legged Hawk in North America, is a medium-large bird of prey. ... Species See text. ... Genera Tetrao Lagopus Falcipennis Centrocercus Bonasa Dendrapagus Tympanuchus Grouse are from the order Galliformes which inhabit temperate and subarctic regions of the northern hemisphere. ... Species Loxia pytyopsittacus Loxia scotia Loxia curvirostra Loxia leucoptera Loxia megaplaga The crossbills are birds in the finch family Fringillidae. ...

Fire

Fire is the dominant natural disturbance in the taiga, as well as being an important disturbance mechanism in many other forest types, such as temperate, sub-alpine and chaparral forests. Large, stand-replacing fires, particularly in the taiga, determine the age distribution and spatial age mosaic of the forested landscape.

Fire suppression

This section may stray from the topic of the article into the topic of another article, Wildfire#Fire suppression. Please help improve this section or discuss this issue on the talk page. (help)

It has been suggested that this article or section be merged into wildfire#Fire suppression. (Discuss)

In North America, the belief that fire suppression has substantially reduced the average annual area burned is widely held by resource managers and is often thought to be self-evident. Direct empirical evidence however is essentially limited to just two studies by Stocks (1991) and Ward and Tithecott (1993), that use Ontario government fire records to make comparisons of average annual area burned between areas with and without aggressive fire suppression policies. Numerous subsequent studies have presented the same information, often in a different format (Martell 1994, Martell 1996, Weber & Stocks 1998, Li 2000, Ward & Mawdsley 2000). The proponents of these studies argue that areas without aggressive fire suppression policies have larger average fire sizes and greater average annual area burned and a longer interval between fires and that this is evidence of the effect of fire suppression. Image File history File links Information_icon. ... {{alternateuses}} The Old Fire burning in the San Bernardino Mountains (image taken from the International Space Station) A wildfire, also known as a forest fire, vegetation fire, grass fire, brush fire, peat fire (gambut in Indonesia), bushfire (in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland... Wikipedia does not have an article with this exact name. ... {{alternateuses}} The Old Fire burning in the San Bernardino Mountains (image taken from the International Space Station) A wildfire, also known as a forest fire, vegetation fire, grass fire, brush fire, peat fire (gambut in Indonesia), bushfire (in Australasia), or hill fire, is an uncontrolled fire often occurring in wildland... Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages None Flower White Trillium Tree Eastern White Pine Bird Common Loon Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation  - House seats  - Senate seats 106 24 Area Total...

However, the idea that fire suppression can effectively reduce the average annual area burned is the focus of a vocal debate in the scientific literature. In particular, several recent papers have argued against this idea (Miyanishi & Johnson 2001, Miyanishi et al. 2002, Bridge et al 2005). These papers claim that statistically rigorous techniques for estimating the average annual area burned, called the fire cycle, do not show changes in the fire cycle associated with fire suppression and that the evidence used to support the effect of fire suppression is biased and has been presented in a way that is flawed. Note that none of these papers criticize fire management agencies for being anything less than completely committed to their mandate. Nor do they suggest that fire personnel are not well trained, efficiently deployed or well managed. Instead, these papers simply suggest that despite the resources employed, fire management agencies are simply unable to effectively reduce the average annual area burned.

The impact that effective fire suppression may have on the average annual area burned is important for many reasons, but in particular, its impact is key to the current paradigm of sustainable forest management in many jurisdictions. One of the core aspects of SFM in many jurisdictions is the use of wood supply models to determine sustainable harvest levels. This determination of sustainable harvest levels often assumes that fire suppression has been effective at reducing the average annual area burned. Thus, if current assumptions about the effect of fire suppression are wrong, the impact on SFM could be substantial.

Evidence that fire suppression has been effective

For the most part, studies that support the effects of fire suppression compare either the number of fires or the average fire size between areas with and without aggressive fire suppression policies. Typically, these studies use the same or similar data from provincial fire records for Ontario covering a span of about 20 years. Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages None Flower White Trillium Tree Eastern White Pine Bird Common Loon Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation  - House seats  - Senate seats 106 24 Area Total...

Proponents of these studies have argued that, firstly, fires are, on average, much larger in areas without aggressive fire suppression policies than in areas with aggressive fire suppression policies because these fires are allowed to spread freely. Secondly, the proponents have argued that far more lightning caused fires are detected in areas with aggressive fire suppression and yet, the average annual area burned is much higher in areas without aggressive fire suppression. It is implied that fire suppression must, therefore, be reducing the area burned by lightning fires.

Recently, Cumming (2005) used novel approaches to analyze multiple components of fire management activity in greater detail than previously done, and confirmed the effectiveness of fire suppression.

Evidence that fire suppression has not been effective

On the other side of the debate, the evidence that fire suppression has not been effective at reducing the average annual area burned has come primarily in two forms. Firstly, in the form of time-since-fire studies, which, it has been argued, do not show detectable changes in the fire cycle that can be associated with fire suppression. Secondly, in the form of criticism of the way that provincial fire records have been used to support the effect of fire suppression.

Numerous time-since fire studies have been done in the temperate, boreal and sub-alpine forests across Canada and the U.S. (reviewed in Johnson 1992, see also Bergeron & Archambault 1993, Johnson & Wowchuck 1993, Johnson et al. 1995, Weir et al. 2000). The techniques used in these studies are felt to be well founded in statistical theory (Johnson & Van Wagner 1985, Johnson & Gutsell 1994, Reed 1994, Reed et al 1998) and recent improvements offer a way to statistically compare different periods of time to see if they possess significantly different fire cycles (Reed 1994, Reed et al 1998). While these studies often show a change in the fire cycle at the beginning of the 20th century, this change is usually associated with large-scale climatic factors, such as the end of the little ice age (Johnson 1992, Bergeron & Archambault 1993, Weir et al. 2000), and not fire suppression. In particular, around Ontario there have been at least six time-since-fire studies that show there has been no change in the fire cycle since 1920 (Heinselmann 1973, Woods & Day 1977, Suffling et al. 1982, Bergeron 1991, Gauthier et al. 2000, and Bridge et al. 2005). In Ontario, active fire suppression activities began sometime in the late 1910's, but these suppression activities are generally thought to be minimal compared with post 1950 when fire suppression began in earnest and technological advances made fire fighting much more effective (OMNR 2002, Thompson 2000). Motto: Ut Incepit Fidelis Sic Permanet (Latin: Loyal she began, loyal she remains) Official languages None Flower White Trillium Tree Eastern White Pine Bird Common Loon Capital Toronto Largest city Toronto Lieutenant-Governor James K. Bartleman Premier Dalton McGuinty (Liberal) Parliamentary representation  - House seats  - Senate seats 106 24 Area Total...

Comparisons of the average annual area burned between areas with and without aggressive fire suppression policies, it is argued, are biased by the fact that small fires are virtually unreported in areas without aggressive fire suppression policies, where detection often relies on reports from settlements or commercial aircraft. Critics have argued that the number of lightning caused fires in areas with and without aggressive fire suppression policies are in fact quite similar and that the smaller average fire size, and the lower proportion of fires in larger size classes in areas with aggressive fire suppression is clearly a consequence of this bias (Miyanishi & Johnson 2001, Miyanishi et al. 2001).

Critics have also argued that despite suppression attempts the actual number of large fires in both areas is quite similar (Miyanishi & Johnson 2001, Miyanishi et al 2001). It has been argued that if fire suppression cannot impact the large fires, then it cannot impact the average annual area burned since almost all of the area is burned by only a few large fires.

Finally, studies that compare areas are also often based on averages of annual area burned made over periods of 12 to 17 years (Martell 1994, 1996, Ward & Tithecott 1993, Li 2000). Some have argued that this is too short a time period because the extreme year to year variation in area burned makes such averages highly variable and difficult to interpret (Johnson et al. 1996, Weir et al. 2000).

Reasons why fire suppression may not have affected the fire cycle

Several people (Weir et al. 1995, Johnson et al. 1995, 1998) have explored reasons why fire suppression may not have affected the fire cycle. In general, they feel that in closed-canopied forests, like the boreal, as little as 3% of the lightning caused fires account for up to 95% of the area burned (Stocks & Street 1993, Johnson & Wowchuck 1993). Most fires remain small, but a few occur under conditions that allow them to increase rapidly in size. It is this small proportion of large lightning caused fires which has the most influence on the area burned and the fire cycle.

In years with a large area burned, fires in these closed-canopied forests characteristically have high intensities, high rates of spread and high duff consumption. In these years, extreme fire behaviour is preceded by a persistent anomalous high pressure system which produces prolonged periods of above normal temperatures and below normal precipitation (Newark 1975, Harrington & Flannigan 1987), and leads to the severe drying of both medium and heavy fuels. Under these extreme conditions, fire behaviour exhibits little difference between aspect, elevation and vegetation type (Anderson 1968, Alexander et al. 1983, Nimchuck 1983, Janz & Nimchuck 1983, Street 1985, Flannigan & Harrington 1988, Fryer & Johnson 1988). In years with only a small area burned, differences in aspect, slope, elevation and vegetation composition can have a significant effect on the fire behaviour (Alexander & McAlpine 1987, Johnson et al 1998), however, the area burned in these years is insignificant. Duff may refer to: // Wildfire terminology The layer of decomposing organic materials that resides between the mineral soil and the litter layer of freshly fallen twigs, needles, and leaves. ...

The extreme fire behaviour associated with persistent high pressure systems results in large areas burned. It has been argued that during these years, it is unlikely that fire suppression can significantly influence the total area burned because under these conditions fire management agencies are quickly overwhelmed (Weir et al. 1995).

See also

• Boreal Forest Conservation Framework

Wikisource has original text related to this article: Boreal Forest Conservation Framework The Boreal Forest Conservation Framework, was adopted December 1, 2003 to preserve the Canadian boreal forest. ...

References

• Arno, S. F. & Hammerly, R. P. 1984. Timberline. Mountain and Arctic Forest Frontiers. The Mountaineers, Seattle. ISBN 0-89886-085-7
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External links

• Boreal Forests/Taiga (WWF)
• Terraformers Canadian Taiga Conservation Foundation
• Arctic and Taiga (Canadian Geographic)
• Coniferous Forest. Earth Observatory. NASA. [1].
• Taiga Rescue Network (TRN) A network of NGOs, indigenous peoples or individuals that works to protect the boreal forests.
• Index of Boreal Forests/Taiga ecoregions at bioimages.vanderbilt.edu
• The Nature Conservancy and its partners work to protect the Canadian Boreal Forest
• Slater museum of natural history: Taiga