View source for Quercus tomentella

{{Short description|Species of tree}}
{{redirect|Island oak}}
{{speciesbox
| image = Island Oak in Santa Rosa Island.jpg
| image_caption = island oak, [[Santa Rosa Island, California|Santa Rosa Island]]
| status = EN
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author=Beckman, E. |author2=Jerome, D. |date=2017 |title=''Quercus tomentella'' |volume=2017 |page=e.T30959A2799049 |doi=10.2305/IUCN.UK.2017-2.RLTS.T30959A2799049.en |access-date=19 November 2021}}</ref>
| genus = Quercus
| display_parents = 2
| parent = Quercus sect. Protobalanus
| species = tomentella
| authority = [[George Engelmann|Engelm.]]
| range_map = Quercus tomentella range map 1.png
| range_map_caption = Natural range of ''Quercus tomentella''
| synonyms_ref = <ref>{{ThePlantList |id=kew-175505 |taxon=Quercus tomentella |authority=Engelm.}}</ref>
| synonyms = {{collapsible list|bullets = true
|''Quercus chrysolepis'' subsp. ''tomentella'' <small>(Engelm.) [[A.E.Murray]]</small>
|''Quercus chrysolepis'' var. ''tomentella'' <small>(Engelm.) A.E.Murray</small>
|''Quercus tomentella'' var. ''conjungens'' <small>[[Trel.]]</small>
|''Quercus tomentella'' f. ''conjungens'' <small>(Trel.) Trel.</small>
}}}}

[[Image:Quercustomentella2.JPG|thumb|right|Foliage]]
'''''Quercus tomentella''''', the '''island oak''',<ref name=jeps>{{Jepson eFlora|40764|Quercus tomentella |first1=Thomas J. |last1=Rosatti |first2=John M. |last2=Tucker |date=2014}}</ref> '''island live oak''',<ref name=usda>{{PLANTS |symbol=QUTO |taxon=Quercus tomentella}}</ref> or '''Channel Island oak''',<ref name=fna>{{eFloras|1|233501090|Quercus tomentella |first=Kevin C. |last=Nixon |volume=3}}</ref> is an [[oak]] in the section [[Quercus section Protobalanus|''Protobalanus'']]. It is native to six islands: five of the [[Channel Islands of California]] and [[Guadalupe Island]], part of [[Baja California]].

It is placed in [[Quercus sect. Protobalanus|''Quercus'' section ''Protobalanus'']].<ref>{{Cite web |last1=Denk |first1=Thomas |last2=Grimm |first2=Guido W. |last3=Manos |first3=Paul S. |last4=Deng |first4=Min |last5=Hipp |first5=Andrew L. |date=2017 |title=Appendix 2.1: An updated infrageneric classification of the oaks |website=figshare |doi=10.6084/m9.figshare.5547622.v1 |url=https://figshare.com/articles/dataset/Appendix_2_1_________An_updated_infrageneric_classification_of_the_oaks/5547622/1 |access-date=2023-02-18 |format=xls |name-list-style=amp }}</ref>

==Description==
Island oak is a [[tree]] growing up to {{convert|20|m|ft|abbr=off}} in height.<ref name=fna/> The mature tree has a grayish to reddish brown trunk with scaly, furrowed [[Bark (botany)|bark]].<ref name=jeps/> The twigs are reddish and covered in woolly hairs. The leathery [[leaf]] blades are often concave and are an oblong lance shape or oval with pointed or rounded tips. The edges are smooth or toothed.<ref name=fna/> The upper surfaces are dark green and lightly hairy when new, losing the hairs over time. The undersides are gray-green and coated in woolly hairs, becoming less woolly with age.<ref name=jeps/> They are usually {{Convert|7 to 10|cm|abbr=off|frac=4}} long, sometimes up to {{Convert|12|cm|abbr=on|frac=4}}. The [[acorn]] grows singly or in pairs. The cup has thick scales and woolly hairs and is up to {{Convert|3|cm|abbr=on|frac=8}} wide. The nut is up to 3.5''&nbsp;''cm with a rounded tip.<ref name=jeps/><ref name=fna/>

==Distribution and habitat==
It is native to six islands: five of the [[Channel Islands of California]] ([[Anacapa Island]], [[San Clemente Island]], [[Santa Catalina Island (California)|Santa Catalina Island]], [[Santa Cruz Island]], and [[Santa Rosa Island (California)|Santa Rosa Island]]) and [[Guadalupe Island]], part of the State of [[Baja California]].<ref name="cnps">{{cite web |date=2013 |title=Quercus tomentella |url=http://www.rareplants.cnps.org/detail/1760.html |work=Inventory of Rare and Endangered Plants |publisher=California Native Plant Society}}</ref>

This species is a [[Relict (biology)|relict]]. Though it is now limited to the islands, it was once widespread in mainland California, as evidenced by the many [[Tertiary|late Tertiary]] [[fossil]]s of the species found there.<ref name="fna" /> Recently, it was found that there was a high genetic variability across many of the ''Q.&nbsp;tomentella'' populations, but this variation was not evenly distributed.<ref>Ashley, M.V., J. R. Backs, L. Kindsvater and S. T. Abraham. 2018. Genetic variation and structure in an endemic island oak, Quercus tomentella and mainland canyon oak, Quercus chrysolepis. International Journal of Plant Science 179</ref>

==Ecology==
Island oak [[Hybrid (biology)|hybridizes]] with [[canyon live oak]] (''Quercus chrysolepis'').<ref name="fna" />

==Conservation==
The island oak was listed as an [[endangered species]] by the [[International Union for Conservation of Nature]].<ref name="iucn status 19 November 2021" />

The species is threatened by [[overgrazing]] from nonnative ungulates. The most rapid declines have occurred on Guadalupe Island.<ref name="iucn status 19 November 2021" /> The trees there are apparently no longer reproducing.<ref name=dela>de la Luz, J. L. L., et al. (2003). [http://www.ingentaconnect.com/content/klu/bioc/2003/00000012/00000005/05094501 On the urgency of conservation on Guadalupe Island, Mexico: is it a lost paradise?] ''Biodiversity and Conservation'' 12(5), 1073-82.</ref> [[Feral goat]]s have been abundant on the island for at least 150 years. The animals have eliminated much of the native vegetation and caused extensive soil [[erosion]]. Fenced enclosures have been helpful in the early recovery of some of the local flora.<ref>Junak, S., et al. (2003). [http://www2.inecc.gob.mx/publicaciones/libros/477/cap6.html Esfuerzos recientes de conservación y apuntes sobre el estado actual de la flora de Isla Guadalupe, Baja California, México.] {{Webarchive|url=https://web.archive.org/web/20160304231607/http://www2.inecc.gob.mx/publicaciones/libros/477/cap6.html |date=2016-03-04 }} (Spanish) Presentation at ''Taller sobre la Restauración y Conservación de Isla Guadalupe'' [Workshop on Restoration and Conservation of Guadalupe Island]. Instituto Nacional de Ecología, November 13–14, 2003. [http://www.ine.gob.mx/ueajei/publicaciones/libros/477/abstracts.html HTML abstract] {{webarchive|url=https://web.archive.org/web/20070819075824/http://www.ine.gob.mx/ueajei/publicaciones/libros/477/abstracts.html |date=August 19, 2007 }} (English)</ref>

==References==
{{Reflist}}

==External links==
*{{Calflora|Quercus tomentella |link=1}}
*{{CalPhotos|Quercus|tomentella}}
*[http://www.tropicos.org/Image/56241 photo of herbarium specimen at Missouri Botanical Garden, collected in Guadalupe Island in 1875]
{{Commons category|Quercus tomentella|position=left}}

{{Taxonbar|from=Q2715180}}

[[Category:Quercus|tomentella]]
[[Category:Flora of California]]
[[Category:Natural history of the Channel Islands of California]]
[[Category:Natural history of the California chaparral and woodlands]]
[[Category:Trees of Northern America]]
[[Category:Trees of mild maritime climate]]
[[Category:Trees of Mediterranean climate]]
[[Category:Garden plants of North America]]
[[Category:Drought-tolerant trees]]
[[Category:Ornamental trees]]
[[Category:Oaks of Mexico]]
[[Category:Trees of Mexican Pacific Islands]]
[[Category:Flora of Guadalupe Island]]