- Quercus tomentella
Taxobox
name = Island Oak
image_width = 200px
image_caption = Island Oak grove,Santa Rosa Island
status = VU
status_system = iucn2.3
regnum =Plant ae
divisio =Magnoliophyta
classis =Magnoliopsida
subclassis =Rosidae
unranked_ordo =Eurosids I
ordo =Fagales
familia =Fagaceae
genus = "Quercus "
sectio = "Protobalanus"
species = "Q. tomentella"
binomial = "Quercus tomentella"
binomial_authority = Engelm.The Island Oak ("Quercus tomentella"), also known as Island Live Oak or Channel Islands Oak, is an
oak in the section "Protobalanus". Island Oak is endemic to six islands off the coast ofCalifornia , Santa Rosa, Santa Cruz, Anacapa, Santa Catalina, San Clemente, and Guadalupe islands. The first five islands areChannel Islands of California ; Guadalupe Island is located to the west ofBaja California ,Mexico .Island Oak is a
tree usually less than 20 meters in height. Its bark is usually gray and becomes furrowed with age. Thespecific name "tomentella",Latin for "beset withtomentum (fuzz)", references the dense hairs found on the undersides of its leaves. Leaves, which areevergreen , are usually 5-8 cm in length, oblong to oblong-obvate in shape, with a toothed margin, deeply indented.Acorns take 2 years to mature and are saucer- to bowl-shaped with a rounded tip, and large in size (cup 20-30 mm wide, 6-8 mm deep, nut 20-35 mm).Island Oak can hybridize with all other members of the section "Protobalanus", although its natural range overlaps only with "Q. chrysolepis", the
Canyon Live Oak .Fossil s of Island Oak have been found in mainland California; the youngest known fossils are two to ten million years old and were found near St. Mary's College, somewhat near the Oakland hills. The oldest known fossils are 30 to 60 million years old and were found in theMojave desert . Island Oak is no longer native to mainland California, and is thought to be a relict of a climate that was warmer and wetter than today's. However, it will grow readily in mainland California if planted and regularly watered.The Island Oak is listed as Vulnerable (VU B1+2ce) by the
IUCN . Many populations are in need of immediate restoration due to severe impacts of grazing by non-nativeherbivore s. TheNational Park Service has classified Island Oak as a species of special environmental concern.On Guadalupe, the local population is probably doomed. It has declined some 80-90% since the 1950s, and one or two dozen trees are all that remains. These do not seem to be reproducing any more. [León de la Luz "et al." (2003), though as oaks have pronounced
mast year cycles, this may just be observational error.] While the Island Oak was once an important part of the localecosystem , its decline was caused by tens of thousands offeral goat s swarming the island since the mid-19th century. Removal of the goats was finally all but complete in 2005 and fenced enclosures have been built since 2001, permitting an amazing comeback of localflora . [Junak "et al." (2003)] Even if the local oaks should disappear, the population could probably be reestablished soon from Channel Islands stock.Footnotes
References
* (2003): "Recent conservation efforts and current status of the flora of Guadalupe Island, Baja California, Mexico". 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]
* (2003): On the urgency of conservation on Guadalupe Island, Mexico: is it a lost paradise? "Biodiversity and Conservation" 12(5): 1073–1082. doi|10.1023/A:1022854211166 (HTML abstract)
* (1997): 39. [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233501090 "Quercus tomentella"] . "In:" aut|Flora of North America Editorial Committee (eds.): "Flora of North America North of Mexico" vol. 3.
*|year=1998|id=30959|title=Quercus tomentella|downloaded=11 May 2006
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