Editing Betula pendula

{{Short description|Species of birch}}
{{Redirect|Silver Birch|the racehorse|Silver Birch (horse)}}
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{{Speciesbox
|name = Silver birch<br />''Betula pendula''
|image_caption = Silver birch forest, [[Inari, Finland|Inari]], Finland
|image = Betula pendula Finland.jpg
|status = LC
|status_system = IUCN3.1
|status_ref = <ref name=IUCN>{{cite iucn | vauthors = Stritch L, Shaw K, Roy S, Wilson B |date=2014 |title=''Betula pendula'' |volume=2014 |page=e.T62535A3115662 |doi=10.2305/IUCN.UK.2014-3.RLTS.T62535A3115662.en |access-date=12 November 2021}}</ref>
|genus = Betula
|parent = Betula subg. Betula
|species = pendula
|authority = [[Albrecht Wilhelm Roth|Roth]]
|subdivision_ranks = Subspecies
|subdivision = See text
|range_map = Betula pendula range.svg
|range_map_caption = Distribution map
|synonyms = See text
}}

'''''Betula pendula''''', commonly known as '''silver birch''', '''warty birch''', '''European white birch''',<ref>[https://treebee.ca/trees/european-white-birch/ European white birch], TD Tree Bee</ref> or '''East Asian white birch''',<ref>{{Cite book |url=http://www.forest.go.kr/kna/special/download/English_Names_for_Korean_Native_Plants.pdf |title=English Names for Korean Native Plants|publisher=[[Korea National Arboretum]]|year=2015|isbn=978-89-97450-98-5|location=Pocheon|pages=373|access-date=26 January 2017|via=[[Korea Forest Service]]|url-status=dead|archive-url=https://web.archive.org/web/20170525105020/http://www.forest.go.kr/kna/special/download/English_Names_for_Korean_Native_Plants.pdf|archive-date=25 May 2017}}</ref> is a [[species]] of tree in the [[family (biology)|family]] [[Betulaceae]], [[native plant|native]] to Europe and parts of Asia, though in southern Europe, it is only found at higher altitudes. Its range extends into Siberia, China, and southwest Asia in the mountains of northern Turkey, the Caucasus, and northern Iran. It has been introduced into North America, where it is known as the '''European white birch''' or '''weeping birch'''<ref>[https://calgaryherald.com/life/homes/tuesday-june-29-2010-whats-wrong-with-your-birch What's Wrong With Your Birch?] Calgary Herald, 29 June 2010</ref> and is considered [[Invasive species|invasive]] in some states in the United States and parts of Canada.

The silver birch is a medium-sized [[deciduous]] tree that owes its common name to the white peeling bark on the trunk. The twigs are slender and often pendulous and the leaves are roughly triangular with [[Glossary of leaf morphology#Edge|doubly serrate]] margins and turn yellow and brown in autumn before they fall. The flowers are [[catkin]]s and the light, winged seeds get widely scattered by the wind. The silver birch is a hardy tree, a [[pioneer species]], and one of the first trees to appear on bare or fire-swept land. Many species of birds and animals are found in birch woodland, the tree supports a wide range of insects and the light shade it casts allows shrubby and other plants to grow beneath its [[Canopy (biology)|canopy]]. It is planted decoratively in parks and gardens and is used for forest products such as joinery timber, firewood, tanning, racecourse jumps, and brooms. Various parts of the tree are used in [[traditional medicine]] and the bark contains [[triterpene]]s, which have been shown to have medicinal properties.

==Description==
[[File:Illustration Betula pendula0.jpg|thumb|left|upright|Silver birch]]
[[File:B. pendula, Koivu Birch, end of August 2.jpg|thumb|right|upright|Silver birch has often pendulous twigs, after which the tree has received its scientific name.]]
The silver birch typically reaches {{convert|15|to|25|m|ft|0|abbr=on}} tall (exceptionally up to {{convert|31|m|ft|abbr=on}}),<ref name=Vedel/> with a slender trunk usually under {{convert|40|cm|in|0|abbr=on}} diameter. The bark on the trunk and branches is golden-brown at first, but later this turns to white as a result of papery tissue developing on the surface and peeling off in flakes, in a similar manner to the closely related [[paper birch]] (''B. papyrifera''). The bark remains smooth until the tree gets quite large, but in older trees, the bark thickens, becoming irregular, dark, and rugged. Young branches have whitish [[resin]] warts and the twigs are slender, hairless, and often [[wikt:pendulous|pendulous]]. The buds are small and sticky, and development is [[sympodial]] – the terminal bud dies away and growth continues from a lateral bud. The species is [[monoecious]] with male and female catkins found on the same tree.<ref name=Vakkari09>{{cite journal| vauthors = Vakkari P |title=Silver birch (''Betula pendula'')|date=2009|journal=EUFORGEN Technical Guidelines for Genetic Conservation and Use|url=http://www.euforgen.org/fileadmin/templates/euforgen.org/upload/Publications/Technical_guidelines/1372_Silver_birch__Betula_pendula_.pdf|access-date=17 January 2017|archive-url=https://web.archive.org/web/20170118051714/http://www.euforgen.org/fileadmin/templates/euforgen.org/upload/Publications/Technical_guidelines/1372_Silver_birch__Betula_pendula_.pdf|archive-date=18 January 2017|url-status=dead}}</ref> Some [[Shoot (botany)|shoot]]s are long and bear the male [[catkin]]s at the tip, while others are short and bear female catkins. The immature male catkins are present during the winter, but the female catkins develop in the spring, soon after the leaves unfurl.<ref name=Vedel/>

The [[leaf|leaves]] have short, slender stalks and are {{convert|3|to|7|cm|in|1|abbr=on}} long, triangular with broad, untoothed, wedge-shaped bases, slender pointed tips, and coarsely double-toothed, serrated margins. They are sticky with resin at first, but this dries as they age, leaving small, white scales. The foliage is a pale to medium green and turns yellow early in the autumn before the leaves fall. In midsummer, the female catkins mature and the male catkins expand and release pollen, and wind pollination takes place. A catkin of Silver birch could produce an average of 1.66 million pollen grains.<ref>{{cite journal | vauthors = Ranpal S, Sieverts M, Wörl V, Kahlenberg G, Gilles S, Landgraf M, Köpke K, Kolek F, Luschkova D, Heckmann T, Traidl-Hoffmann C, Büttner C, Damialis A, Jochner-Oette S | title = Is Pollen Production of Birch Controlled by Genetics and Local Conditions? | journal = International Journal of Environmental Research and Public Health | volume = 19 | issue = 13 | page = 8160 | date = July 2022 | pmid = 35805818 | pmc = 9266428 | doi = 10.3390/ijerph19138160 | doi-access = free }}</ref> The small, 1- to 2-mm winged [[seed]]s ripen in late summer on pendulous, cylindrical catkins {{convert|2|to|4|cm|in|1|abbr=on}} long and {{convert|7|mm|1|abbr=on}} broad. The seeds are very numerous and are separated by scales, and when ripe, the whole catkin disintegrates and the seeds are spread widely by the wind.<ref name=Vedel/><ref name=tfl/>

Silver birch can easily be confused with the similar [[downy birch]] (''Betula pubescens''). Yet, downy birches are characterised by hairy leaves and young shoots, whereas the same parts on silver birch are hairless. The leaf base of silver birch is usually a right angle to the stalk, while for downy birches, it is rounded. In terms of [[genetic structure]], the trees are quite different, but do, however, occasionally [[Hybridization (biology)|hybridize]].<ref name=Vakkari09/>
[[File:Betula pendula - Childwall Woods & Fields 01.jpg|thumb|upright|''Betula pendula'' silver birch catkins and leaves, Childwall Woods & Fields, [[Merseyside]]]]

==Distribution and habitat==
The silver birch grows naturally from western Europe eastwards to [[Kazakhstan]], the [[Sakha Republic]] in [[Siberia]], Mongolia, and the [[Xinjiang]] province in China, and southwards to the mountains of the Caucasus and northern Iran, Iraq, and Turkey. It is also native to northern Morocco and has become naturalised in some other parts of the world.<ref name=GRIN>{{GRIN | access-date=2014-05-29}}</ref> In the southern parts of its range, it is mainly found in mountainous regions. Its light seeds are easily blown by the wind and it is a pioneer species, one of the first trees to sprout on bare land or after a forest fire. It needs plenty of light and does best on dry, acid soils and is found on heathland, mountainsides, and clinging to crags.<ref name=Vedel>{{cite book |title=Trees and Bushes | vauthors = Vedel H, Lange J |year=1971 |publisher=Methuen |isbn=978-0-416-61780-1 |pages=[https://archive.org/details/treesbushesinwoo0000vede/page/141 141–143] |url=https://archive.org/details/treesbushesinwoo0000vede/page/141 }}</ref> Its tolerance to pollution make it suitable for planting in industrial areas and exposed sites.<ref name=Forestry>{{cite web |url=http://www.forestry.gov.uk/forestry/INFD-5NLDXL |title=Silver birch: ''Betula pendula'' |publisher=Forestry Commission |access-date=2014-05-28 |archive-date=29 May 2014 |archive-url=https://web.archive.org/web/20140529051546/http://www.forestry.gov.uk/forestry/INFD-5NLDXL |url-status=dead }}</ref> It has been introduced into North America, where it is known as the European white birch, and is considered [[Invasive species|invasive]] in the states of [[Kentucky]], [[Maryland]], [[Washington (state)|Washington]], and [[Wisconsin]].<ref name=USDA>{{cite web |url=http://www.na.fs.fed.us/fhp/invasive_plants/weeds/european-white-birch.pdf |title=European White Birch – ''Betula pendula'' |date=2006-09-01 |publisher=USDA Forest Service |access-date=2014-05-29}}</ref> It is [[naturalisation (biology)|naturalised]] and locally invasive in parts of [[Canada]].<ref>{{cite journal | vauthors = Diamond J, Browning M, Williams A, Middleton J |year=2003 |title=Lack of Evidence for Impact of the European White Birch, ''Betula pendula'', on the Hydrology of Wainfleet Bog, Ontario |journal=Canadian Field-Naturalist |volume=117 |issue=3 |page=393 |doi=10.22621/cfn.v117i3.741 |url=http://canadianfieldnaturalist.ca/index.php/cfn/article/view/741 |doi-access=free }}</ref>

==Taxonomy==
{{See also|List of Betula species}}
[[File:Breza na jesen.jpg|thumb|right|upright|Tree in autumn]]
[[File:Betula pendula winter.jpg|thumb|right|upright|Tree in winter]]
Three [[subspecies]] of silver birch are accepted:<ref name=powo>{{cite web|title=''Betula pendula'' Roth.|url=https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:295174-1|website=Plants of the World Online|publisher=Royal Botanical Gardens Kew |access-date=2018-10-28}}</ref><ref name=IUCN/>
* ''Betula pendula'' subsp. ''pendula'' – Europe and eastwards to central Asia
* ''Betula pendula'' subsp. ''mandshurica'' <small>(Regel) Ashburner & McAll.</small> – eastern Asia and western North America; treated by some botanists as ''[[Betula platyphylla]]''<ref name=hunt1993>{{cite book | veditors = Hunt D | date = 1993 | chapter = Betula | title = Proceedings of the IDS Betula Symposium 2–4 October 1992 | page = 51 | publisher = International Dendrology Society | isbn = 0-9504544-5-1}}</ref>
* ''Betula pendula'' subsp. ''szechuanica'' <small>(C.K.Schneid.) Ashburner & McAll.</small> – western China, from [[Qinghai]] and [[Gansu]] to [[Yunnan]] and southeast [[Xizang]] ([[Tibet]]), treated by some botanists as ''[[Betula szechuanica]]''<ref name=hunt1993/>

''B. pendula'' is distinguished from the related ''B. pubescens'', the other common European birch, in having hairless, warty shoots (hairy and without warts in downy birch), more triangular leaves with double serration on the margins (more ovoid and with single serrations in downy birch), and whiter bark often with scattered black fissures (greyer, less fissured, in downy birch). It is also distinguished [[cell biology|cytologically]], silver birch being [[diploid]] (with two sets of chromosomes), whereas downy birch is [[tetraploid]] (four sets of chromosomes). Hybrids between the two are known, but are very rare, and being triploid, are sterile.<ref>{{cite book|author=OECD|title=Novel Food and Feed Safety SET 1: Safety Assessment of Transgenic Organisms OECD Consensus Documents Volumes 1 and 2 |url=https://books.google.com/books?id=JMW8UloBZqMC&pg=RA1-PA58 |year=2008 |publisher=OECD Publishing |isbn=978-92-64-05346-5|pages=58}}</ref> The two have differences in [[habitat (ecology)|habitat]] requirements, with silver birch found mainly on dry, [[sand]]y soils, and downy birch more common on wet, poorly drained sites such as [[clay]] soils and [[peat bog]]s. Silver birch also demands slightly more summer warmth than does downy birch, which is significant in the cooler parts of Europe. Many North American texts treat the two species as conspecific (and cause confusion by combining the downy birch's alternative vernacular name 'white birch', with the scientific name ''B. pendula'' of the other species), but they are regarded as distinct species throughout Europe.<ref name=tfl/>

Several [[variety (botany)|varieties]] of ''B. pendula'' are no longer accepted, including ''B. pendula'' var. ''carelica'', ''fontqueri'', ''laciniata'', ''lapponica'', ''meridionalis'', ''microlepis'', and ''parvibracteata'', as well as [[form (botany)|forms]] ''Betula pendula'' f. ''bircalensis'', ''crispa'', and ''palmeri''.<ref name=powo/> Other synonyms include:<ref name=powo/><ref>{{cite web |url=http://linnaeus.nrm.se/flora/di/betula/betul/betupen.html |title=''Betula pendula'' Roth | vauthors = Anderberg A |date=1999-10-14 |work=Den virtuella floran |publisher=Naturhistoriska riksmuseet |access-date=2014-05-29}}</ref> 
{{columns-list|colwidth=25em|
* The rejected name ''Betula alba'' <small>L.</small> also applied in part to ''B. pendula'', though also to ''B. pubescens''<ref>{{Cite journal | vauthors = Govaerts R | year = 1996 | title = Proposal to reject the name ''Betula alba'' (Betulaceae) | journal = Taxon | volume = 45 | pages = 697–698 | doi=10.2307/1224262| jstor = 1224262 }}</ref>
* ''Betula brachylepis'' <small>V.N.Vassil.</small>
* ''Betula cajanderi f. fruticans'' <small>Kozhevn.</small>
* ''Betula carpatica var. sudetica'' <small>Rchb.</small>
* ''Betula coriacea'' <small>Pamp.</small>
* ''Betula cycoviensis'' <small>Steud.</small>
* ''Betula ellipticifolia'' <small>V.N.Vassil.</small>
* ''Betula etnensis'' <small>Raf.</small>, sometimes spelled ''B. aetnensis''<ref name=IUCN/>
* ''Betula ferganensis'' <small>V.N.Vassil.</small>
* ''Betula fontqueri'' <small>Rothm.</small>
* ''Betula gummifera'' <small>Bertol.</small>
* ''Betula hybrida'' <small>Blom</small>
* ''Betula insularis'' <small>V.N.Vassil.</small>
* ''Betula kossogolica'' <small>V.N.Vassil.</small>
* ''Betula laciniata'' <small>(Wahlenb.) Rchb.</small>
* ''Betula lobulata'' <small>Kit.</small>
* ''Betula ludmilae'' <small>V.N.Vassil.</small>
* ''Betula microlepis'' <small>I.V.Vassil.</small>
* ''Betula mongolica'' <small>V.N.Vassil.</small>
* ''Betula montana'' <small>V.N.Vassil.</small>
* ''Betula oycowiensis'' <small>Besser</small>, sometimes spelled ''B. oycoviensis''<ref name=IUCN/>
* ''Betula palmata'' <small>Borkh.</small>
* ''Betula parvibracteata'' <small>Peinado, G.Moreno & A.Velasco</small>
* ''Betula platyphylloides'' <small>V.N.Vassil.</small>
* ''Betula pseudopendula'' <small>V.N.Vassil.</small>
* ''Betula szaferi'' <small>Jent.-Szaf. ex Staszk.</small>
* ''Betula talassica'' <small>Poljakov</small>
* ''Betula tiulinae'' <small>V.N.Vassil.</small>
* ''Betula transbaicalensis'' <small>V.N.Vassil.</small>
* ''Betula tristis'' <small>Dippel</small>
* ''Betula verrucosa'' <small>Ehrh.</small>
* ''Betula virgultosa'' <small>Fr. ex Regel</small>
* ''Betula vladimirii'' <small>V.N.Vassil.</small>
}}

==Ecology==
The silver birch has an open canopy which allows plenty of light to reach the ground. This allows a variety of mosses, grasses, and flowering plants to grow beneath, which in turn attract insects. Flowering plants often found in birch woods include [[Primula vulgaris|primrose]] (''Primula vulgaris''), [[Viola riviniana|violet]] (''Viola riviniana''), [[Hyacinthoides non-scripta|bluebell]] (''Hyacinthoides non-scripta''), [[Anemone nemorosa|wood anemone]] (''Anemone nemorosa''), and [[Oxalis acetosella|wood sorrel]] (''Oxalis acetosella''). Small shrubs that grow on the forest floor include [[blaeberry]] (''Vaccinium myrtillus'') and [[cowberry]] (''Vaccinium vitis-idaea'').<ref name=tfl>{{cite web |url=http://treesforlife.org.uk/forest/birch/ |title=Silver birch, downy birch | vauthors = Featherstone AW |publisher=Trees for Life |access-date=2014-05-28}}</ref>
Birds found in birch woodland include the [[Common chaffinch|chaffinch]], [[tree pipit]], [[willow warbler]], [[Common nightingale|nightingale]], [[European robin|robin]], [[Eurasian woodcock|woodcock]], [[Common redpoll|redpoll]], and [[European green woodpecker|green woodpecker]].<ref name=Forestry/>

The branches of the silver birch often have tangled masses of twigs known as [[witch's broom]]s growing among them, caused by the fungus ''[[Taphrina]] betulina''. Old trees are often killed by the decay fungus ''[[Fomitopsis betulina]]'' and fallen branches rot rapidly on the forest floor. This tree commonly grows with the [[mycorrhiza]]l fungus ''[[Amanita muscaria]]'' in a [[Mutualism (biology)|mutualistic]] relationship. This applies particularly to acidic or nutrient-poor soils. Other mycorrhizal associates include ''[[Leccinum scabrum]]'' and ''[[Cantharellus cibarius]]''.<ref name=tfl/> In addition to mycorrhiza, the presence of microfauna in the soil assists the growth of the tree, as it enhances the mobilization of nutrients.<ref>{{cite journal | vauthors = Setälä H, Huhta V |year=1991 |title=Soil Fauna Increase ''Betula pendula'' Growth: Laboratory Experiments With Coniferous Forest Floor |journal=Ecology |volume=72 |issue=2 |pages=665–671 |jstor=2937206 |doi=10.2307/2937206|bibcode=1991Ecol...72..665S }}</ref>

[[File:Sawfly larvae on silver birch 140701 (Tony Holkham).JPG|thumb|Birch [[sawfly]] (''[[Craesus septentrionalis]]''<!--[[Nematinae]]<ref>[http://eol.org/pages/3766113/overview EOL]</ref>-->) larvae feeding on silver birch, West Wales, July 2014]]
The larvae of a large number of species of butterflies, moths, and other insects feed on the leaves and other parts of the silver birch.<ref>{{cite web |url=http://www.nhm.ac.uk/research-curation/research/projects/hostplants/ |title=HOSTS – a Database of the World's Lepidopteran Hostplants [Data set] |date=2023 | location = London, England | publisher = Natural History Museum |doi=10.5519/havt50xw |access-date=2014-05-29 | vauthors = Robinson GS, Ackery PR, Kitching IJ, Beccaloni GW, Hernández LM }}</ref> In Germany, almost 500 species of insects have been found on silver and downy birch including 106 beetles and 105 [[lepidoptera]]ns, with 133 insect species feeding almost exclusively on birch.<ref>{{cite journal | vauthors = Brändle M, Brandl R |year=2001 |title=Species richness of insects and mites on trees: expanding Southwood |journal=Journal of Animal Ecology |volume=70 |issue=3 |pages=491–504 |doi=10.1046/j.1365-2656.2001.00506.x |doi-access=free |bibcode=2001JAnEc..70..491B }}</ref> [[Birch dieback]] disease can affect planted trees, while naturally regenerated trees seem less susceptible.<ref name=WoodlandTrust>{{cite web |url=https://www.woodlandtrust.org.uk/visiting-woods/trees-woods-and-wildlife/british-trees/native-trees/downy-birch/ |title=Birch, downy (''Betula pubescens'') |publisher=Woodland Trust |access-date=10 May 2016 |archive-url=https://web.archive.org/web/20190220143319/http://www.woodlandtrust.org.uk/visiting-woods/trees-woods-and-wildlife/british-trees/native-trees/downy-birch/ |archive-date=20 February 2019 |url-status=dead }}</ref> This disease also affects ''B. pubescens'' and in 2000 was reported at many of the sites planted with birch in Scotland during the 1990s.<ref>{{cite web |url=http://www.forestry.gov.uk/fr/infd-67uerg |title=Dieback of birch |publisher= Forestry Commission |access-date=10 May 2016}}</ref> In the United States, the wood is attacked by the bronze birch borer (''[[Agrilus anxius]]''), an insect pest to which it has no natural resistance.<ref name=USDA/>

==Conservation==
''Betula pendula'' is considered a species of least concern by the [[IUCN Red List]].<ref name=IUCN/> The synonym ''Betula oycowiensis'' (as ''B. oycoviensis'') was previously listed on the Red List as vulnerable,<ref name=iucnboycoviensis>{{citation |title=''Betula oycoviensis'' in IUCN 2009 | vauthors = Boratynski A |work=IUCN Red List of Threatened Species. Version 2009.1 |publisher=[[International Union for Conservation of Nature and Natural Resources]] |year=1998}}</ref> though it is now considered a synonym of ''B. pendula'' subsp. ''pendula''.<ref name=IUCN/><ref name=powo/> ''B. szaferi'' was previously considered extinct in the wild on the Red List, but is now considered a form of ''B. pendula'' with the presence of a mutant gene, causing it to grow weakly and fruit heavily.<ref name=IUCN/>

==Uses==
{{See also|Birch bark|Curly birch}}
[[File:2014-10-30 09 58 18 Birch foliage during autumn along Terrace Boulevard in Ewing, New Jersey.jpg|thumb|Foliage coloring in autumn]]
[[File:HAZELIUS(1881) Vol.1, Abb.9, p037.jpg|thumb|A pair of Finnish traditional shoes woven from strips of birch bark]]

The silver birch is Finland's [[List of national trees|national tree]].<ref>{{cite web|title=Suomen kansallistunnukset (Finland's national emblems) |year=2005 | vauthors = Anttila K |url=http://www.kolumbus.fi/webweaver/tunnus.html|access-date=2014-05-30}}</ref> Leafy, fragrant bunches of young silver birch boughs (called ''vihta'' or ''vasta'') are used to gently beat oneself while bathing in the Finnish [[sauna]].<ref>{{cite web |title=Perinteinen saunavihta (Traditional sauna vihta) |publisher=Visit sauna |url=http://www.visitsauna.fi/fi/sauna/saunavihta/saunavihta |access-date=2014-05-30 |archive-url=https://web.archive.org/web/20141102041416/http://www.visitsauna.fi/fi/sauna/saunavihta/saunavihta |archive-date=2 November 2014 |url-status=dead |language=fi}}</ref> Silver birch is often planted in parks and gardens, grown for its white bark and gracefully drooping shoots, sometimes even in warmer-than-optimum places such as [[Los Angeles]] and [[Sydney]].  In Scandinavia and other regions of northern Europe, it is grown for forest products such as lumber and pulp, as well as for aesthetic purposes and [[ecosystem services]].  It is sometimes used as a [[Pioneer species|pioneer]] and nurse tree elsewhere.<ref name=Vedel/>

Silver birch wood is pale in colour with a light reddish-brown heartwood and is used in making furniture, plywood, veneers, parquet blocks, skis, and kitchen utensils, and in [[turnery]]. It makes a good firewood, but is quickly consumed by the flames. Slabs of bark are used for making [[Wood shingle|roof shingles]] and strips are used for handicrafts such as [[bast shoe]]s and small containers.<ref name=Vedel/> Historically, the bark was used for [[Tanning (leather)|tanning]]. Bark can be heated and the resin collected; the resin is an excellent waterproof glue and useful for starting fires. The thin sheets of bark that peel off young wood contain a waxy resin and are easy to ignite even when wet. The dead twigs are also useful as kindling for outdoor fires.<ref name=Cox>{{cite web |url=http://www.woodstovewizard.com/firewood-types-silver-birch.html |title=Firewood types: silver birch | vauthors = Cox MD |publisher=WoodstoveWizard.com |access-date=2014-05-29}}</ref> The removal of bark was at one time so widespread that [[Carl Linnaeus]] expressed his concern for the survival of the woodlands.<ref>{{cite web |url=http://www.nordicwellbeing.com/Julies_Kitchen/2011/01/09/bark-bread-is-back/ |title=Bark Bread is back |date=2011-01-09 |work=Nordic Wellbeing | vauthors = Lindahl J |access-date=2011-07-21}}</ref>

Birch brushwood is used for [[Steeplechase (horse racing)|racecourse jumps]] and [[besom]] brooms. In the spring, large quantities of sap rise up the trunk and this can be tapped. It contains around 1% sugars and can be used in a similar way to [[maple syrup]], being drunk fresh, concentrated by evaporation, or fermented into a "wine".<ref name=Cox/>

===Phytochemicals===
The outer part of the [[bark (botany)|bark]] contains up to 20% [[betulin]]. The main components in the essential oil of the [[buds]] are [[α-copaene]] (~10%), [[germacrene D]] (~15%), and [[δ-cadinene]] (~13%).<ref>{{cite journal | vauthors = Demirci B, Paper DH, Demirci F, Can Başer KH, Franz G | title = Essential Oil of Betula pendula Roth. Buds | journal = Evidence-Based Complementary and Alternative Medicine | volume = 1 | issue = 3 | pages = 301–303 | date = December 2004 | pmid = 15841263 | pmc = 538512 | doi = 10.1093/ecam/neh041 }}</ref> Also present in the bark are other [[triterpene]] substances which have been used in laboratory research to identify its possible biological properties.<ref>{{cite journal | vauthors = E Kovac-Besović E, Durić K, Kalodera Z, Sofić E | title = Identification and isolation of pharmacologically active triterpenes in Betuale cortex, Betula pendula Roth., Betulaceae | journal = Bosnian Journal of Basic Medical Sciences | volume = 9 | issue = 1 | pages = 31–38 | date = February 2009 | pmid = 19284392 | pmc = 5645545 | doi = 10.17305/bjbms.2009.2853 }}</ref>

=== Medical uses ===
{{anchor|Medical uses}}
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| legal_CA_comment  = <ref>{{cite web|url=https://pdf.hres.ca/dpd_pm/00064325.PDF |title=ITULATEK : Standardized Allergen Extract, White Birch (Betula Verrucosa)|website=Pdf.hres.ca|access-date=8 June 2022}}</ref>
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Standardized allergen extract, white birch, sold under the brand name '''Itulatek''', is [[indicated]] for the treatment of allergy to tree pollen from birch, alder and/or hazel and have allergic rhinitis (with or without conjunctivitis).<ref>{{cite web | title=Regulatory Decision Summary – Itulatek | website=Health Canada | date=23 October 2014 | url=https://hpr-rps.hres.ca/reg-content/regulatory-decision-summary-detail.php?linkID=RDS00632 | access-date=7 June 2022}}</ref><ref>{{cite web | title=Itulatek Product information | website=Health Canada | date=25 April 2012 | url=https://health-products.canada.ca/dpd-bdpp/info.do?lang=en&code=98787 | access-date=7 June 2022}}</ref>

The combination of [[Birch bark#Medical uses|''Betula pendula''/''Betula pubescens'']] is used to treat [[epidermolysis bullosa]].<ref name="Filsuvez EPAR">{{cite web | title=Filsuvez EPAR | website=[[European Medicines Agency]] (EMA) | date=13 April 2022 | url=https://www.ema.europa.eu/en/medicines/human/EPAR/filsuvez | access-date=6 July 2022 | archive-date=6 July 2022 | archive-url=https://web.archive.org/web/20220706033550/https://www.ema.europa.eu/en/medicines/human/EPAR/filsuvez | url-status=live }} Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.</ref> The combination of these is also used to make Episalvan gel, which is used to treat wounds in upper layers of the skin.<ref>{{cite journal | vauthors = Rastogi S, Pandey MM, Kumar Singh Rawat A | title = Medicinal plants of the genus Betula--traditional uses and a phytochemical-pharmacological review | journal = Journal of Ethnopharmacology | volume = 159 | pages = 62–83 | date = January 2015 | pmid = 25449458 | pmc = 7126499 | doi = 10.1016/j.jep.2014.11.010 }}</ref>

Leaf extracts of ''Betula pendula'' have been used to treat both [[rheumatoid arthritis]] and [[osteoarthritis]]. The extracts inhibit cell growth and cell division of the activated [[T cell|T lymphocytes]] by inducing apoptosis in the cell. This causes a decrease in inflammation caused by arthritis.<ref>{{cite journal | vauthors = Gründemann C, Gruber CW, Hertrampf A, Zehl M, Kopp B, Huber R | title = An aqueous birch leaf extract of Betula pendula inhibits the growth and cell division of inflammatory lymphocytes | journal = Journal of Ethnopharmacology | volume = 136 | issue = 3 | pages = 444–451 | date = July 2011 | pmid = 21619918 | doi = 10.1016/j.jep.2011.05.018 | series = Immunomodulators }}</ref>

Betula pendula and Betula pubescens have the potential to treat cancer because of anti-carcinogenic properties. These buds contain stantin and cirsimaritin. Santin is a flavonol that expresses anti-inflammatory characteristics, which suppresses genes associated with cancer. Both santin and cirsimaritin induce [[apoptosis]] of cancer cells.<ref>{{cite journal | vauthors = Szoka L, Nazaruk J, Stocki M, Isidorov V | title = Santin and cirsimaritin from Betula pubescens and Betula pendula buds induce apoptosis in human digestive system cancer cells | journal = Journal of Cellular and Molecular Medicine | volume = 25 | issue = 24 | pages = 11085–11096 | date = December 2021 | pmid = 34755444 | pmc = 8650031 | doi = 10.1111/jcmm.17031 }}</ref> ''Betula pendula'' bark extracts inhibit growth of in vitro malignant human cell lines: skin epidermoid carcinoma, ovarian carcinoma, cervix adenocarcinoma, and breast adenocarcinoma. ''Betula pendula'' bark extract is also effective for treating [[actinic keratosis]].<ref>{{cite journal | vauthors = Rastogi S, Pandey MM, Kumar Singh Rawat A | title = Medicinal plants of the genus Betula--traditional uses and a phytochemical-pharmacological review | journal = Journal of Ethnopharmacology | volume = 159 | pages = 62–83 | date = January 2015 | pmid = 25449458 | pmc = 7126499 | doi = 10.1016/j.jep.2014.11.010 }}</ref>

==Cultivation==
[[Image:Betula pendula laciniata0.jpg|thumb|upright|right|''B. pendula'' 'Laciniata']]
Successful birch cultivation requires a climate cool enough for at least the occasional winter snowfall. As they are shallow-rooted, they may require water during dry periods. They grow best in full sun planted in deep, well-drained soil.<ref>{{cite book |title=Botanica's Trees & Shrubs  |year=1999 |publisher=Laurel Glen Publishing | location = San Diego, Calif. |page=139 |isbn=978-1-57145-649-6 }}</ref>

===Cultivars and varieties===
* 'Carelica' or "[[curly birch]]" is called ''visakoivu'' in Finland. The wood is hard and [[burl]]ed throughout; it is prized for its decorative appearance and is used in wood-carving and as veneer.<ref>{{cite web |title=''Betula pendula'' var. carelica – curly birch |date=24 April 2013 |url=http://www.mustila.fi/en/plants/betula/pendula/carelica |publisher=Arboretum Mustila |access-date=2014-11-12 |archive-date=18 December 2014 |archive-url=https://web.archive.org/web/20141218003605/http://www.mustila.fi/en/plants/betula/pendula/carelica |url-status=dead }}</ref>
* 'Laciniata' {{smallcaps|agm}}<ref>{{cite web | url = https://www.rhs.org.uk/Plants/91605/Betula-pendula-Laciniata/Details
| title = ''Betula pendula'' 'Laciniata' | publisher = RHS | access-date = 12 April 2020}}</ref> (commonly misidentified as [[Ornäs Birch|'Dalecarlica']]) has deeply incised leaves and weeping branches
* 'Purpurea' has dark purple leaves<ref>{{cite web|title=RHS Plant Selector – ''Betula pendula'' 'Purpurea'|url=https://www.rhs.org.uk/Plants/97920/i-Betula-pendula-i-Purpurea/Details |publisher=Royal Horticultural Society |access-date=2014-11-12}}</ref>
* 'Tristis' {{smallcaps|agm}}<ref>{{cite web | url = https://www.rhs.org.uk/Plants/92577/Betula-pendula-Tristis/Details
| title = ''Betula pendula'' 'Tristis' | publisher = RHS | access-date = 12 April 2020}}</ref> has an erect trunk with weeping branchlets
* 'Youngii' has dense, twiggy, weeping growth with no central leader and requires being grafted onto a standard stem of normal silver birch.<ref>{{cite web|title=RHS Plant Selector – ''Betula pendula'' 'Youngii'|url=https://www.rhs.org.uk/Plants/92990/i-Betula-pendula-i-Youngii/Details |publisher=Royal Horticultural Society |access-date=2014-11-12}}</ref>

The cultivars marked {{smallcaps|agm}} above have gained the [[Royal Horticultural Society]]'s [[Award of Garden Merit]].
[[File:Birch-Betula-pendula-Tromsø.JPG|thumb|right|200px|''Betula pendula'' in [[Tromsø]] in May, [[Northern Norway]].]]

== References ==
{{Reflist}}

== External links ==
{{Commons category}}
* [http://www.euforgen.org/species/betula-pendula/ ''Betula pendula''] – distribution map, genetic conservation units and related resources. [[European Forest Genetic Resources Programme]] (EUFORGEN)
* {{PFAF|Betula pendula}}
* {{CalPhotos|Betula|pendula}}

{{Taxonbar|from=Q156895}}
{{Authority control}}

[[Category:Betula|pendula]]
[[Category:Flora of Europe]]
[[Category:Trees of Europe]]
[[Category:Trees of Russia]]
[[Category:Trees of humid continental climate]]
[[Category:National symbols of Finland]]
[[Category:Trees of continental subarctic climate]]
[[Category:Plants described in 1788]]
[[Category:Taxa named by Albrecht Wilhelm Roth]]