Editing Tree line (section)

==Worldwide distribution==

===Alpine tree lines===
[[File:Treeline elevation.gif|thumb|right|Treeline elevation by latitude<ref>{{cite journal|last1=Testolin|first1=Riccardo|last2=Attorre|first2=Fabio|last3=Jiménez-Alfaro|first3=Borja|year=2020|title=Global distribution and bioclimatic characterization of alpine biomes|journal=Ecography|volume=43|issue=6 |pages=779–788 |doi=10.1111/ecog.05012|bibcode=2020Ecogr..43..779T |hdl=11585/896830|hdl-access=free}}</ref>]]

The alpine tree line at a location is dependent on local variables, such as [[aspect (geography)|aspect]] of slope, [[rain shadow]] and proximity to either [[geographical pole]]. In addition, in some tropical or island localities, the lack of biogeographical access to species that have evolved in a [[subalpine zone|subalpine]] environment can result in lower tree lines than one might expect by climate alone.{{cn|date=July 2023}}

Averaging over many locations and local [[microclimate]]s, the treeline rises {{convert|75|m|ft|round=5}} when moving 1 degree south from 70 to 50°N, and {{convert|130|m|ft}} per degree from 50 to 30°N. Between 30°N and 20°S, the treeline is roughly constant, between {{convert|3500|and|4000|m|ft}}.<ref name=korner/>

Here is a list of approximate tree lines from locations around the globe:
{{clear right}}
{| class="wikitable sortable"
|-
! style="text-align:left;" rowspan="2" class="unsortable"|Location
! style="text-align:left;" rowspan="2"|Approx. latitude
!colspan=2|Approx. elevation of tree line
!rowspan="2" class="unsortable"|Notes
|-
! style="text-align:center;"|(m)
! style="text-align:center;"|(ft)
|-
|[[Finnmarksvidda]], Norway
|data-sort-value="69"|69°N
| {{convert|500|m|ft|-2|disp=table}}
|At 71°N, near the coast, the tree-line is below sea level (Arctic tree line).
|-
|[[Abisko]], Sweden
|data-sort-value="68"|68°N
| {{convert|650|m|ft|-2|disp=table}}
|<ref name=korner/>
|-
|[[Chugach Mountains|Chugach Mountains, Alaska]]
|data-sort-value="61"|61°N
| {{convert|700|m|ft|-2|disp=table}}
|Tree line around {{convert|1500|ft|m}} or lower in coastal areas
|-
|Southern Norway
|data-sort-value="61"|61°N
| {{convert|1100|m|ft|-2|disp=table}}
|Much lower near the coast, down to {{convert|500|–|600|m|ft}}.
|-
|Scotland, United Kingdom
|data-sort-value="57"|57°N
| {{convert|500|m|ft|-2|disp=table}}
|Strong maritime influence serves to cool summer and restrict tree growth<ref name="Scotland">{{Cite web |title=Action For Scotland's Biodiversity |url=http://www.scotland.gov.uk/Resource/Doc/314275/0099822.pdf}}</ref>{{rp|79}}
|-
|[[Northern Quebec]]
|data-sort-value="56"|56°N
| {{convert|0|m|ft|-2|disp=table}}
| The cold [[Labrador Current]] originating in the arctic makes eastern Canada the sea-level region with the most southern tree-line in the northern hemisphere.
|-
|Southern [[Ural Mountains|Urals]]
|data-sort-value="55"|55°N
| {{convert|1100|m|ft|-2|disp=table}}
|
|-
|[[Canadian Rockies]]
|data-sort-value="51"|51°N
| {{convert|2400|m|ft|-2|disp=table}}
|
|-
|[[Tatra Mountains]]
|data-sort-value="49"|49°N
| {{convert|1600|m|ft|-2|disp=table}}
|
|-
|[[Olympic Mountains]], Washington, United States
|data-sort-value="47"|47°N
| {{convert|1500|m|ft|-2|disp=table}}
|Heavy winter snowpack buries young trees until late summer
|-
|[[Swiss Alps]]
|data-sort-value="47"|47°N
| {{convert|2200|m|ft|-2|disp=table}}
|<ref name=korner1/>
|-
|[[Mount Katahdin]], [[Maine]], United States
|data-sort-value="46"|46°N
| {{convert|1150|m|ft|-2|disp=table}}
|
|-
|[[Eastern Alps]], Austria, Italy
|data-sort-value="46"|46°N
| {{convert|1750|m|ft|-2|disp=table}}
| More exposure to [[Siberian High|cold Russian winds]] than Western Alps
|-
|[[Sikhote-Alin]], Russia
|data-sort-value="46"|46°N
| {{convert|1600|m|ft|-2|disp=table}}
| <ref name="Sikhote">{{Cite web |title=Physiogeography of the Russian Far East |url=http://geobotanica.ru/PH_GEO/phys.html}}</ref>
|-
|Alps of [[Piedmont]], Northwestern Italy
|data-sort-value="45"|45°N
| {{convert|2100|m|ft|-2|disp=table}}
|-
|[[New Hampshire]], United States
|data-sort-value="44"|44°N
| {{convert|1350|m|ft|-2|disp=table}}
| <ref>{{Cite web |title=Mount Washington State Park |url=http://www.nhstateparks.com/washington.html |archive-url=https://web.archive.org/web/20130403200610/http://nhstateparks.com/washington.html |archive-date=2013-04-03 |access-date=2013-08-22 |publisher=New Hampshire State Parks |quote=Tree line, the elevation above which trees do not grow, is about 4,400 feet in the White Mountains, nearly 2,000 feet below the summit of Mt. Washington.}}</ref> Some peaks have even lower treelines because of fire and subsequent loss of soil, such as [[Grand Monadnock]] and [[Mount Chocorua]].
|-
|[[Wyoming]], United States
|data-sort-value="43"|43°N
| {{convert|3000|m|ft|-2|disp=table}}
|
|-
|[[Caucasus Mountains]]
|data-sort-value="42"|42°N
| {{convert|2400|m|ft|-2|disp=table}}
| <ref>{{Cite web |title=Georgia's natural resources and conservation |url=https://www.geostat.ge/media/19691/saqarTvelos-bunebrivi-resursebi-da-garemos-dacva_2008.pdf |access-date=2023-04-13 |website=geostat.ge |publisher=National Statistic Office of Georgia |language=ka}}</ref>
|-
|[[Rila]] and [[Pirin]] Mountains, [[Bulgaria]]
|data-sort-value="42"|42°N
| {{convert|2300|m|ft|-2|disp=table}}
| Up to {{convert|2600|m|ft|abbr=on}} on favorable locations. [[Mountain Pine]] is the most common tree line species.
|-
|[[Pyrenees]] Spain, France, [[Andorra]]
|data-sort-value="42"|42°N
| {{convert|2300|m|ft|-2|disp=table}}
| [[Mountain Pine]] is the tree line species
|-
|[[Steens Mountain]], [[Oregon]], US
|data-sort-value="42"|42°N
|{{convert|2500|m|ft|-2|disp=table}}
|-
|[[Wasatch Mountains]], [[Utah]], United States
|data-sort-value="40"|40°N
| {{convert|2900|m|ft|-2|disp=table}}
|Higher (nearly {{convert|11,000|ft|m|disp=or}} in the [[Uintas]])
|-
| rowspan="2" |[[Rocky Mountain National Park|Rocky Mountain NP]], [[Colorado|CO]], United States
| rowspan="2" data-sort-value="40"|40°N
| {{convert|3550|m|ft|-2|disp=table}}
|<ref name=korner/> On warm southwest slopes
|-
| {{convert|3250|m|ft|-2|disp=table}}
|On northeast slopes
|-
| rowspan="2" | [[Yosemite National Park|Yosemite]], [[California|CA]], United States
| rowspan="2" data-sort-value="38"|38°N
| {{convert|3200|m|ft|-2|disp=table}}
|<ref name="Schoenherr">{{Cite book |last=Schoenherr |first=Allan A. |title=A Natural History of California |title-link=A Natural History of California |publisher=UC Press |year=1995 |isbn=978-0-520-06922-0}}</ref> West side of [[Sierra Nevada (U.S.)|Sierra Nevada]]
|-
| {{convert|3600|m|ft|-2|disp=table}}
|<ref name=Schoenherr/> East side of Sierra Nevada
|-
|[[Sierra Nevada (Spain)|Sierra Nevada]], Spain
|data-sort-value="37"|37°N
| {{convert|2400|m|ft|-2|disp=table}}
|Precipitation low in summer
|-
|[[Japanese Alps]]
|data-sort-value="36"|36°N
| {{convert|2900|m|ft|-2|disp=table}}
|
|-
|[[Khumbu]], [[Himalaya]]
|data-sort-value="28"|28°N
| {{convert|4200|m|ft|-2|disp=table}}
|<ref name=korner/>
|-
|[[Yushan (mountain)|Yushan]], [[Taiwan]]
|data-sort-value="23"|23°N
|{{convert|3600|m|ft|-2|disp=table}}
|<ref name="Yushan">{{Cite web |title=台灣地帶性植被之區劃與植物區系之分區 |url=http://conservation.forest.gov.tw/public/Data/5111513445271.PDF |archive-url=https://web.archive.org/web/20141129065554/http://conservation.forest.gov.tw/public/Data/5111513445271.PDF |archive-date=2014-11-29}}</ref> Strong winds and poor soil restrict further grow of trees.
|-
|[[Hawaii]], United States
|data-sort-value="20"|20°N
| {{convert|3000|m|ft|-2|disp=table}}
|<ref name=korner/> Geographic isolation and no local tree species with high tolerance to cold temperatures.
|-
|[[Pico de Orizaba]], Mexico
|data-sort-value="19"|19°N
| {{convert|4000|m|ft|-2|disp=table}}
|<ref name="korner1">{{Cite web |last=Körner |first=Ch |title=High Elevation Treeline Research |url=http://pages.unibas.ch/botschoen/treeline_elevation/index.shtml |archive-url=https://web.archive.org/web/20110927151628/http://pages.unibas.ch/botschoen/treeline_elevation/index.shtml |archive-date=2011-09-27 |access-date=2010-06-14}}</ref>
|-
|[[Costa Rica]]
|data-sort-value="9.5"|9.5°N
| {{convert|3400|m|ft|-2|disp=table}}
|
|-
|[[Mount Kinabalu]], [[Borneo]]
|data-sort-value="6.1"|6.1°N
| {{convert|3400|m|ft|-2|disp=table}}
|<ref name="mount_kinabalu">{{Cite web |date=4 September 2016 |title=Mount Kinabalu National Park |url=http://www.ecologyasia.com/html-loc/mount-kinabalu.htm |access-date=6 September 2016 |website=www.ecologyasia.com |publisher=Ecology Asia}}</ref>
|-
|[[Mount Kilimanjaro]], [[Tanzania]]
|data-sort-value="-3"|3°S
| {{convert|3100|m|ft|-2|disp=table}}
|<ref name="korner">{{Cite journal |last=Körner |first=Ch |year=1998 |title=A re-assessment of high elevation treeline positions and their explanation |journal=Oecologia |volume=115 |issue=4 |pages=445–459 |bibcode=1998Oecol.115..445K |citeseerx=10.1.1.454.8501 |doi=10.1007/s004420050540 |pmid=28308263 |s2cid=8647814}}</ref> Upper limit of forest trees; woody ericaeous scrub grows up to 3900m
|-
|[[New Guinea]]
|data-sort-value="-6"|6°S
| {{convert|3850|m|ft|-2|disp=table}}
|<ref name=korner/>
|-
|[[Andes]], [[Peru]]
|data-sort-value="-11"|11°S
| {{convert|3900|m|ft|-2|disp=table}}
|East side; on west side tree growth is restricted by dryness
|-
| rowspan="2" |[[Andes]], [[Bolivia]]
| rowspan="2" data-sort-value="-18" |18°S
| {{convert|5200|m|ft|disp=table}}
|Western Cordillera; highest treeline in the world on the slopes of [[Sajama Volcano]] (Polylepis tarapacana)
|-
| {{convert|4100|m|ft|-2|disp=table}}
|Eastern Cordillera; treeline is lower because of lower solar radiation (more humid climate)
|-
|[[Sierra de Córdoba]], [[Argentina]]
|data-sort-value="-31"|31°S
| {{convert|2000|m|ft|-2|disp=table}}
|Precipitation low above [[trade winds]], also high exposure
|-
| rowspan="2" |[[Australian Alps]], [[New South Wales]], [[Australia]]
| rowspan="2" data-sort-value="-36"|36°S
|-
| {{convert|1800|m|ft|-2|disp=table}}
|Despite the far inland location, summers are cool relative to the latitude, with occasional summer snow; and heavy springtime snowfalls are common<ref>{{Cite web |title=Alpine trees &#124; ANU Research School of Biology |url=https://biology.anu.edu.au/news-events/news/alpine-trees}}</ref>
|-
|[[Andes]], [[Laja Lake|Laguna del Laja]], [[Chile]]
|data-sort-value="-37"|37°S
| {{convert|1600|m|ft|-2|disp=table}}
|Temperature rather than precipitation restricts tree growth<ref name="Lara">{{Cite journal |last1=Lara |first1=Antonio |last2=Villalba |first2=Ricardo |author-link2=Ricardo Villalba |last3=Wolodarsky-Franke |first3=Alexia |last4=Aravena |first4=Juan Carlos |last5=Luckman |first5=Brian H. |last6=Cuq |first6=Emilio |year=2005 |title=Spatial and temporal variation in Nothofagus pumilio growth at tree line along its latitudinal range (35°40′–55° S) in the Chilean Andes |url=http://www.osara.org/darwin_2009/articles/Lara%20et%20al%202005.pdf |journal=[[Journal of Biogeography]] |volume=32 |issue=5 |pages=879–893 |doi=10.1111/j.1365-2699.2005.01191.x |bibcode=2005JBiog..32..879L |s2cid=51845387}}</ref>
|-
|[[Mount Taranaki]], [[North Island]], New Zealand
|data-sort-value="-39"|39°S
| {{convert|1500|m|ft|-2|disp=table}}
|Strong maritime influence serves to cool summer and restrict tree growth
|-
| Northeast [[Tasmania]], [[Australia]]
| data-sort-value="-41" |41°S
| {{convert|1200|m|ft|disp=table}}
|Although sheltered on the [[Southeast Australian foehn|leeward]] side of the island, summers are still cool for the latitude.
|-
| Southwest [[Tasmania]], [[Australia]]
| data-sort-value="-43" |43°S
| {{convert|750|m|ft|-2|disp=table}}
|Exposed to the [[Roaring Forties|westerly storm track]], summer is extraordinarily cool for the latitude, with frequent summer snow. Springtime receives an extreme amount of cold, heavy precipitation; winds are likewise extreme.
|-
|[[Fiordland]], [[South Island]], New Zealand
|data-sort-value="-45"|45°S
| {{convert|950|m|ft|-2|disp=table}}
|Very snowy springs, strong cold winds and cool summers with frequent summer snow restrict tree growth{{citation needed|date=July 2014}}
|-
|[[Lago Argentino]], Argentina
|data-sort-value="-50"|50°S
| {{convert|1000|m|ft|-2|disp=table}}
|''[[Nothofagus pumilio]]''<ref>{{Cite journal |last1=Sottile |first1=Gonzalo D. |last2=Echeverría |first2=Marcos E. |last3=Tonello |first3=Marcela S. |last4=Marcos |first4=María A. |last5=Bamonte |first5=Florencia P. |last6=Rayó |first6=Cecilia |last7=Mancini |first7=María V. |year=2020 |title=Dinámica de la vegetación andina del lago Argentino (50° S, 72° O) desde el retiro de los glaciares (ca. 12.000 años cal AP) |url=http://www.andeangeology.cl/index.php/revista1/article/view/V47n3-3303/html |journal=[[Andean Geology]] |language=es |volume=47 |issue=3 |pages=599–627 |doi=10.5027/andgeoV47n3-3303 |doi-access=free |bibcode=2020AndGe..47..599S |hdl-access=free |hdl=11336/141218}}</ref>
|-
|[[Torres del Paine National Park|Torres del Paine]], [[Chile]]
|data-sort-value="-51"|51°S
| {{convert|950|m|ft|-2|disp=table}}
|Strong influence from the [[Southern Patagonian Ice Field]] serves to cool summer and restrict tree growth<ref name="Patagonia">{{Cite journal |last1=Aravena |first1=Juan C. |last2=Lara |first2=Antonio |last3=Wolodarsky-Franke |first3=Alexia |last4=Villalba |first4=Ricardo |author-link4=Ricardo Villalba |last5=Cuq |first5=Emilio |year=2002 |title=Tree-ring growth patterns and temperature reconstruction from Nothofagus pumilio (Fagaceae) forests at the upper tree line of southern, Chilean Patagonia |journal=[[Revista Chilena de Historia Natural]] |volume=75 |issue=2 |doi=10.4067/S0716-078X2002000200008 |doi-access=free |hdl-access=free |hdl=11336/40918}}</ref>
|-
|[[Navarino Island]], [[Chile]]
|data-sort-value="-55"|55°S
| {{convert|600|m|ft|-2|disp=table}}
|Strong maritime influence serves to cool summer and restrict tree growth<ref name=Patagonia/>
|}

===Arctic tree lines===
[[File:Canada tree line map.png|thumb|right|Map of tree line in Canada]]
Like the alpine tree lines shown above, polar tree lines are heavily influenced by local variables such as [[aspect (geography)|aspect]] of slope and degree of shelter. In addition, [[permafrost]] has a major impact on the ability of trees to place roots into the ground. When roots are too shallow, trees are susceptible to [[windthrow]] and erosion. Trees can often grow in river [[valleys]] at latitudes where they could not grow on a more exposed site. Maritime influences such as [[ocean currents]] also play a major role in determining how far from the equator trees can grow as well as the warm summers experienced in extreme continental climates.{{cn|date=July 2023}} In northern inland [[Scandinavia]] there is substantial maritime influence on high parallels that keep winters relatively mild, but enough inland effect to have summers well above the threshold for the tree line. Here are some typical polar treelines:
{{Clear}}
{| class="wikitable sortable"
|-
!align="left" class="unsortable"|Location
!align="left"|Approx. longitude
!Approx. latitude of tree line
!class="unsortable"|Notes
|-
|Norway
|{{sort|024|24°E}}
| style="text-align:center;"|70°N
|The [[North Atlantic current]] makes Arctic climates in this region warmer than other coastal locations at comparable latitude. In particular the mildness of winters prevents [[permafrost]].
|-
|[[West Siberian Plain]]
|{{sort|075|75°E}}
| style="text-align:center;"|66°N
|
|-
|[[Central Siberian Plateau]]
|{{sort|102|102°E}}
| style="text-align:center;"|72°N
|Extreme [[continental climate]] means the summer is warm enough to allow tree growth at higher latitudes, extending to northernmost forests of the world at 72°28'N at [[Ary-Mas]] (102° 15' E) in the [[Novaya River]] valley, a tributary of the [[Khatanga River]] and the more northern [[Lukunsky grove]] at 72°31'N, 105° 03' E east from Khatanga River.
|-
|[[Russian Far East]] ([[Kamchatka Peninsula|Kamchatka]] and [[Chukchi Peninsula|Chukotka]])
|{{sort|160|160°E}}
| style="text-align:center;"|60°N
|The [[Oyashio Current]] and strong winds affect summer temperatures to prevent tree growth. The [[Aleutian Islands]] are almost completely treeless.
|-
|[[Alaska]], United States
|{{sort|208|152°W}}
| style="text-align:center;"|68°N
|Trees grow north to the south-facing slopes of the Brooks Range. The mountains block cold air coming off of the Arctic Ocean.
|-
|[[Northwest Territories]], Canada
|{{sort|228|132°W}}
| style="text-align:center;"|69°N
|Reaches north of the Arctic Circle because of the continental nature of the climate and warmer summer temperatures.
|-
|[[Nunavut]]
|{{sort|265|95°W}}
| style="text-align:center;"|61°N
|Influence of the very cold [[Hudson Bay]] moves the treeline southwards.
|-
|[[Labrador Peninsula]]
|{{sort|293|72°W}}
| style="text-align:center;"|56°N
|Very strong influence of the Labrador Current on summer temperatures as well as altitude effects (much of Labrador is a plateau). In parts of [[Labrador]], the treeline extends as far south as 53°N. Along the coast the northernmost trees are at 58°N in [[Napartok Bay]].
|-
|[[Greenland]]
|{{sort|315|50°W}}
| style="text-align:center;"|69°N
|Determined by experimental tree planting in the absence of native trees because of isolation from natural seed sources; a very few trees are surviving, but growing slowly, at [[Kangerlussuaq Fjord|Søndre Strømfjord]], 67°N. There is one natural forest in the [[Qinngua Valley]].
|}

===Antarctic tree lines===
Trees exist on [[Tierra del Fuego]] (55°S) at the southern end of South America, but generally not on [[List of Antarctic and subantarctic islands|subantarctic islands]] and not in Antarctica. Therefore, there is no explicit Antarctic tree line.{{cn|date=September 2024}}

[[Kerguelen Island]] (49°S), [[South Georgia Island|South Georgia]] (54°S), and other subantarctic islands are all so heavily wind-exposed and with a too-cold summer climate (tundra) that none have any indigenous tree species. The [[Wildlife of the Falkland Islands|Falkland Islands]] (51°S) summer temperature is near the limit, but the islands are also treeless, although some planted trees exist.{{cn|date=September 2024}}

[[Antarctic Peninsula]] is the northernmost point in Antarctica (63°S) and has the mildest weather—it is located {{convert|1080|km|mi}} from [[Cape Horn]] on [[Tierra del Fuego]]—yet no trees survive there; only a few mosses, lichens, and species of grass do so. In addition, no trees survive on any of the subantarctic islands near the peninsula.{{cn|date=September 2024}}

[[File:BeagleChannelGlacier.jpg|thumb|Trees growing along the north shore of the [[Beagle Channel]], 55°S.]]
Southern [[Metrosideros|Rata]] forests exist on [[Enderby Island]] and [[Auckland Islands]] (both 50°S) and these grow up to an elevation of {{convert|1200|ft|m|order=flip}} in sheltered valleys. These trees seldom grow above {{convert|3|m|ft|abbr=on}} in height and they get smaller as one gains altitude, so that by {{convert|600|ft|m|abbr=on|order=flip}} they are waist-high. These islands have only between 600 and 800 hours of sun annually. [[Campbell Island, New Zealand|Campbell Island]] (52°S) further south is treeless, except for one stunted Spruce, probably planted in 1907.<ref>{{Cite news |last=Morwood |first=Maddy |date=4 Sep 2022 |title=How the world's loneliest tree is helping scientists advance climate change research |url=https://www.abc.net.au/news/2022-09-05/the-worlds-loneliest-tree-advance-climate-change-research/101247300 |publisher=Australian Broadcasting Company}}</ref> The climate on these islands is not severe, but tree growth is limited by almost continual rain and wind. Summers are very cold with an average January temperature of {{convert|9|C|F|abbr=on}}. Winters are mild {{convert|5|C|F|abbr=on}} but wet. [[Macquarie Island]] (Australia) is located at 54°S and has no vegetation beyond snow grass and alpine grasses and mosses.{{Citation needed|date=October 2011}}