Editing Taiga (section)

==Climate and geography==
[[File:Siberian autumn in taiga..JPG|thumb|[[Siberia]]n taiga]]
Taiga covers {{convert|abbr=off|17|e6km2|e6sqmi}} or 11.5% of the Earth's land area,<ref>{{cite web|url=http://www.wilds.mb.ca/taiga/tbsfaq.html |title=Taiga biological station: FAQ |publisher=Wilds.m.ca |access-date=21 February 2011}}</ref> second only to [[deserts and xeric shrublands]].<ref name="Berkeley"/> The largest areas are located in Russia and Canada. In [[Sweden]] taiga is associated with the [[Norrland terrain]].<ref>{{cite book |last=Sporrong |first=Ulf |chapter=The Scandinavian landscape and its resources |editor-last=Helle |editor-first=Knut|date=2003 |title=The Cambridge History of Scandinavia |url=https://archive.org/details/cambridgehistory01hell |url-access=limited |publisher=Cambridge University Press |issue=1 |pages=[https://archive.org/details/cambridgehistory01hell/page/n655 22] |isbn=9780521472999 }}</ref>

===Temperature===
After the permanent ice caps and [[tundra]], taiga is the terrestrial [[biome]] with the lowest annual average temperatures, with mean annual temperature generally varying from {{cvt|−5|to|5|C|F}}.<ref>{{cite web|url=http://www.marietta.edu/~biol/biomes/boreal.htm |title=Marietta the Taiga and Boreal forest |publisher=Marietta.edu |access-date=21 February 2011}}</ref> Extreme winter minimums in the northern taiga are typically lower than those of the tundra. There are taiga areas of eastern Siberia and interior Alaska-[[Yukon]] where the mean annual temperature reaches down to {{cvt|−10|C|F}},<ref>{{cite web|url=http://www.worldclimate.com/cgi-bin/data.pl?ref=N62E129+1102+24959W |title=Yakutsk climate |publisher=Worldclimate.com |date=4 February 2007 |access-date=21 February 2011}}</ref><ref>{{WWF ecoregion|id=na0607 |name= Interior Alaska-Yukon lowland taiga |access-date=21 February 2011}}</ref> and the [[Oymyakon|lowest reliably recorded temperatures]] in the [[Northern Hemisphere]] were recorded in the taiga of northeastern Russia.

Taiga has a [[subarctic climate]] with very large temperature range between seasons. {{cvt|−20|C|F}} would be a typical winter day temperature and {{cvt|18|C|F}} an average summer day, but the long, cold winter is the dominant feature. This climate is classified as ''Dfc'', ''Dwc'', ''Dsc'', ''Dfd'' and ''Dwd'' in the [[Köppen climate classification]] scheme,<ref>{{cite web |url=http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/taiga/taiga.html |title=radford:Taiga climate |publisher=Radford.edu |access-date=21 February 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110609021800/http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/taiga/taiga.html |archive-date=9 June 2011 }}</ref> meaning that the short summers (24&nbsp;h average {{cvt|10|C|F}} or more), although generally warm and humid, only last 1–3 months, while winters, with average temperatures below freezing, last 5–7 months.

In Siberian taiga the average temperature of the coldest month is between {{convert|-6|°C}} and {{convert|-50|°C}}.<ref name="VOL page 568">''Encyclopedia Universalis'' édition 1976 Vol. 2 ASIE – Géographie physique, p. 568 {{in lang|fr}}</ref> 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]]s (''Dfb'', ''Dwb'') with longer summers.

According to some sources, the boreal forest grades into a temperate mixed forest when mean annual temperature reaches about {{cvt|3|C|F}}.<ref>{{WWF ecoregion|id=na0406 |name=The eastern forest – boreal transition|access-date=21 February 2011}}</ref> [[Discontinuous permafrost]] is found in areas with mean annual temperature below freezing, whilst in the ''Dfd'' and ''Dwd'' climate zones [[continuous permafrost]] occurs and restricts growth to very shallow-rooted trees like [[Siberian larch]].

===Growing season===
[[File:Shovel Point1.jpg|thumb|Boreal forest near Shovel Point in [[Tettegouche State Park]], along the northern shore of Lake Superior in [[Minnesota]].]]
The [[growing season]], when the vegetation in the taiga comes alive, is usually slightly longer than the climatic definition of summer as the plants of the boreal biome have a lower temperature threshold to trigger growth than other plants. Some sources claim 130 days growing season as typical for the taiga.<ref name="Berkeley"/>

In Canada and Scandinavia, the growing season is often estimated by using the period of the year when the 24-hour average temperature is {{convert|+5|C}} or more.<ref>{{Cite web|url=http://www.enr.gov.nt.ca/_live/documents/documentManagerUpload/Taiga_Shield_References.pdf|title=Canada: Taiga Shield reference|website=Enr.gov.nt.ca|access-date=28 February 2022}}{{Dead link|date=March 2022 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> For the Taiga Plains in Canada, growing season varies from 80 to 150 days, and in the Taiga Shield from 100 to 140 days.<ref>{{cite web |url=http://geography.ridley.on.ca/CGC1D/Students/NORTH/Geography%20Project/Ecozones.htm |title=Climate of Canadian ecozones |publisher=Geography.ridley.on.ca |access-date=21 February 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110505201153/https://geography.ridley.on.ca/CGC1D/Students/NORTH/Geography%20Project/Ecozones.htm |archive-date=5 May 2011 }}</ref>

Other sources define growing season by frost-free days.<ref>{{cite web |url=http://www.blueplanetbiomes.org/taiga.htm |title=Taiga |publisher=Blueplanetbiomes |access-date=21 February 2011 |archive-url=https://web.archive.org/web/20110410093754/http://www.blueplanetbiomes.org/taiga.htm |archive-date=10 April 2011 |url-status=dead }}</ref> Data for locations in southwest Yukon gives 80–120 frost-free days.<ref>{{cite web |url=http://yukon.taiga.net/swyukon/frost.cfm |title=Southwest Yukon:Frost-free days |publisher=Yukon.taiga.net |access-date=21 February 2011 |url-status=usurped |archive-url=https://web.archive.org/web/20110724091601/https://yukon.taiga.net/swyukon/frost.cfm |archive-date=24 July 2011 }}</ref> The closed canopy boreal forest in [[Kenozersky National Park]] near [[Plesetsk]], [[Arkhangelsk Oblast|Arkhangelsk Province]], Russia, on average has 108 frost-free days.<ref>{{cite web|url=http://www.wild-russia.org/bioregion2/2-KenozerskyNP/2_kenoz.htm |title=Kenozersky National Park |publisher=Wild-russia.org |access-date=21 February 2011}}</ref>

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.<ref>{{cite web|url=http://www.sekj.org/PDF/anzf31/anz31-123-129.pdf |title=University of Helsinki: Carabid diversity in Finnish taiga |access-date=21 February 2011}}</ref> The shortest growing season is found at the northern taiga–tundra [[ecotone]], where the northern taiga forest no longer can grow and the tundra dominates the landscape when the growing season is down to 50–70 days,<ref>{{cite web|url=http://www.blueplanetbiomes.org/tundra.htm |title=Tundra |publisher=Blueplanetbiomes |access-date=21 February 2011}}</ref><ref>{{cite web|url=http://www.nhptv.org/NatureWorks/nwep8a.htm |title=NatureWorks:Tundra |publisher=Nhptv.org |access-date=21 February 2011}}</ref> and the 24-hr average of the warmest month of the year usually is {{cvt|10|C|F}} or less.<ref>{{cite web |url=http://www.saskschools.ca/~gregory/arctic/Aintro.html |title=The Arctic |publisher=saskschools.ca |access-date=21 February 2011 |url-status=dead |archive-url=https://web.archive.org/web/20110410080512/https://www.saskschools.ca/~gregory/arctic/Aintro.html |archive-date=10 April 2011 }}</ref>

High [[latitude]]s mean that the [[sun]] 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, or up to 24 hours, with only around 6 hours of daylight, or none, occurring in the dark winters, depending on latitude. The areas of the taiga inside the [[Arctic Circle]] have [[midnight sun]] in mid-summer and [[polar night]] in mid-winter.

===Precipitation===
The taiga experiences relatively low [[Precipitation (meteorology)|precipitation]] throughout the year (generally {{cvt|200|–|750|mm|in}} annually, {{cvt|1,000|mm|in}} in some areas), primarily as [[rain]] during the summer months, but also as [[snow]] or [[fog]]. Snow may remain on the ground for as long as nine months in the northernmost extensions of the taiga biome.<ref>A.P. Sayre, ''Taiga'', (New York: Twenty-First Century Books, 1994) 16.</ref>

The fog, especially predominant in low-lying areas during and after the thawing of frozen Arctic seas, stops sunshine from getting through to plants even during the long summer days. As [[evaporation]] is consequently low for most of the year, annual precipitation exceeds evaporation, and is sufficient to sustain the dense vegetation growth including large trees. This explains the striking difference in biomass per square metre between the Taiga and the [[Steppe]] biomes, (in warmer climates), where evapotranspiration exceeds precipitation, restricting vegetation to mostly grasses.

[[File:Skjomtinden & Kongsbakktinden from Bogen, 2010 September.JPG|thumb|Late September in the [[fjord]]s near [[Narvik]], Norway. This oceanic part of the forest can see more than {{cvt|1,000|mm|in}} precipitation annually and has warmer winters than the vast inland taiga.]]

In general, taiga grows to the south of the {{cvt|10|C|F}} July [[Isotherm (contour line)|isotherm]], occasionally as far north as the {{cvt|9|C|F}} July isotherm,<ref>Arno & Hammerly 1984, Arno ''et al.'' 1995</ref> with the southern limit more variable. Depending on rainfall, and taiga may be replaced by [[forest steppe]] south of the {{cvt|15|C|F}} July isotherm where rainfall is very low, but more typically extends south to the {{cvt|18|C|F}} July isotherm, and locally where rainfall is higher, such as in eastern [[Siberia]] and adjacent [[Outer Manchuria]], south to the {{cvt|20|C|F}} 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 [[Temperate broadleaf and mixed forests|mixed temperate forest]] or, more locally (on the [[Pacific Ocean]] coasts of North America and Asia), into coniferous [[temperate rainforest]]s where oak and hornbeam appear and join the conifers, birch and [[Populus tremula]].

===Glaciation===
The area currently classified as taiga in Europe and North America (except Alaska) was [[Wisconsin glaciation|recently glaciated]]. As the glaciers receded they left [[Kettle (geology)|depressions]] in the topography that have since filled with water, creating [[lake]]s and [[bog]]s (especially [[muskeg]] soil) found throughout the taiga.

[[File:Yukon River near Carmacks, Yukon -a.jpg|thumb|right|[[Yukon River]], Canada. Several of the world's longest rivers go through the taiga, including [[Ob River|Ob]], [[Yenisei River|Yenisei]], [[Lena River|Lena]], and [[Mackenzie River|Mackenzie]].]]

<gallery widths="200px" heights="160px">
File:Talkessel von Werchojansk.JPG|The taiga in the river valley near [[Verkhoyansk]], [[Russia]], at 67°N, experiences the coldest winter temperatures in the northern hemisphere, but the extreme continentality of the climate gives an average daily high of {{cvt|22|C|F}} in July
File:Helvetinjärvi.JPG|Lakes and other water bodies are common in the taiga. The [[Helvetinjärvi National Park]], Finland, is situated in the closed canopy taiga (mid-boreal to south-boreal)<ref>{{cite web|url=http://131.95.113.139/courses/multivariate/Diatom_community.pdf|title=Finland vegetation zone and freshwater biome|website=113.139|access-date=19 April 2018|archive-date=11 September 2011|archive-url=https://web.archive.org/web/20110911201301/http://131.95.113.139/courses/multivariate/Diatom_community.pdf|url-status=dead}}</ref> with mean annual temperature of {{cvt|4|C|F}}.<ref>{{cite web|url=http://www.worldclimate.com/cgi-bin/data.pl?ref=N61E023+1102+02944W |title=Tampere/Pirkkala, Finland Weather History and Climate Data |publisher=Worldclimate.com |date=2007-02-04 |access-date=2011-02-21}}</ref>
</gallery>