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
| status = EN
| status_system = IUCN3.1
| genus = Quercus
| display_parents = 2
| parent = Quercus sect. Protobalanus
| species = tomentella
| authority = Engelm.
| range_map = Quercus tomentella range map 1.png
| range_map_caption = Natural range of Quercus tomentella
| synonyms_ref = {{ThePlantList |id=kew-175505 |taxon=Quercus tomentella |authority=Engelm.}}
| synonyms = {{collapsible list|bullets = true
|Quercus chrysolepis subsp. tomentella (Engelm.) A.E.Murray
|Quercus chrysolepis var. tomentella (Engelm.) A.E.Murray
|Quercus tomentella var. conjungens Trel.
|Quercus tomentella f. conjungens (Trel.) Trel.
}}}}
Quercus tomentella, the island oak,{{Jepson eFlora|40764|Quercus tomentella |first1=Thomas J. |last1=Rosatti |first2=John M. |last2=Tucker |date=2014}} island live oak,{{PLANTS |symbol=QUTO |taxon=Quercus tomentella}} or Channel Island oak,{{eFloras|1|233501090|Quercus tomentella |first=Kevin C. |last=Nixon |volume=3}} is an oak in the section 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 section Protobalanus.{{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 }}
Description
Island oak is a tree growing up to {{convert|20|m|ft|abbr=off}} in height. The mature tree has a grayish to reddish brown trunk with scaly, furrowed bark. 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. 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. 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 cm with a rounded tip.
Distribution and habitat
It is native to six islands: five of the Channel Islands of California (Anacapa Island, San Clemente Island, Santa Catalina Island, Santa Cruz Island, and Santa Rosa Island) and Guadalupe Island, part of the State of Baja California.{{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}}
This species is a relict. Though it is now limited to the islands, it was once widespread in mainland California, as evidenced by the many late Tertiary fossils of the species found there. Recently, it was found that there was a high genetic variability across many of the Q. tomentella populations, but this variation was not evenly distributed.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
Ecology
Island oak hybridizes with canyon live oak (Quercus chrysolepis).
Conservation
The island oak was listed as an endangered species by the International Union for Conservation of Nature.
The species is threatened by overgrazing from nonnative ungulates. The most rapid declines have occurred on Guadalupe Island. The trees there are apparently no longer reproducing.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. Feral goats 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.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)
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: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