- Quercus chrysolepis
Taxobox
name = "Quercus chrysolepis"
image_caption = Leaves and acorn
status_system = iucn2.3
regnum =Plant ae
divisio = Magnoliophyta
classis =Magnoliopsida
ordo =Fagales
familia =Fagaceae
genus = "Quercus"
sectio = "Protobalanus"
species = "Q. chrysolepis"
binomial = "Quercus chrysolepis"
binomial_authority = Liebm."Quercus chrysolepis", commonly termed Canyon live oak, is a
species ofevergreen oak that is found in the southwestern part ofNorth America , notably in theCalifornia Coast Ranges . This tree is often found near creeks and drainage swales growing in moist cool microhabitats. Its leaves are a glossy dark green on the upper surface with prominent spines; a further rapid identification arises from the leaves of Canyon live oak being geometrically flat. They are often sympatric with "Quercus agrifolia " and several other oak species.Fossil data supports a much wider distribution throughout thewestern United States during the earlyHolocene period.Native Americans used the
acorn s of this species as a food staple, afterleaching of thetannin s; moreover, its roasted seed is acoffee substitute. After forest fires, Canyon live oak regenerates vigorously by basal sprouting, and the clonal diversity of this species has been shown to be high. [A.M. Montalvo, S.G. Conard, M.T. Conkle and P.D. Hodgskiss, "Population structure, genetic diversity, and clone formation in Quercus chrysolepis (Fagaceae)", American Journal of Botany, Vol 84, 1553, (1997)] Alternate common names for this taxon are Canyon oak and "Golden-Cup Oak".Morphology
"Quercus chrysolepis" is an evergreen tree with significant-sized spreading, horizontal branches, and a broad, rounded crown; it attains a height of six to thirty meters and is often found in a shrubby growth form. The trunk diameter can range from 30 to 100 centimeters. The elliptical to oblong leaves are 2.5 to 8.0 centimeters in length with widths of about half that dimension; moreover, leaves are short-pointed at the tip, but rounded or blunt at base. Although the leaves appear generally flat, they may have edge margins slightly turned under, typically with spiny teeth, particularly on young twigs. These leathery leaves are a glossy dark green above, with a nether surface a dull golden down, [Bruce M. Pavlik, Pamela C. Muick, Sharon Johnson and Marjorie Popper, "Oaks of California", Cachuma Press (1992) ISBN 0-9628505-1-9] often becoming gray and nearly
glabrous the second year.Bark of the Canyon live oak is of a light gray coloration, and is rather smooth or sometimes scaly.
Acorn s occur solitarily or in pairs, exhibiting lengths of two to five centimeters; these fruits are variable in size and shape, but generallyovoid , turban-like with a shallow, thick cup of scales densely covered with yellowish hairs; the stalk is barely evident.Range and habitat
Canyon live oak is found in a variety of
forest communities in thesouthwestern United States . It is found in 1.12 million acres (4,500 km²) of forest inCalifornia alone, including coast ranges and discontinuous occurrence on the eastern slopes of the southern and central Sierra Nevada. This tree is rare east of theCascade-Sierra crest. Scattered, disjunct populations are found in the mountainous regions of southwestNevada and in portions of western and centralArizona , and northwestMexico .Canyon live oak is tolerant of a variety of
soil types, including very rocky or cobbly environments. It is hardy to cold temperatures down to - 11 °F, and will grow in neutral to moderatelyacid ic soils withpH ranges of 4.5 to 7.5. Canyon live oak grows at elevations of about 500 to 1500 meters in southwesternOregon ; inNorthern California , from 100 to 1400 meters; and inSouthern California , up to approximately 2700 meters. "Quercus chrysolepis" can be the dominant tree on steep canyon walls, especially in locations of shallow rocky soils. [McDonald, Philip M., and Edward E. Littrell, 1976. "The bigcone Douglas-fir-canyon live oak community in southern California", Madroño 23:310-320] In areas of moderate to highrainfall , it occurs on south facing slopes, and in the hotter, drier parts of its distribution, on northerly slope faces.Ecology
Besides the prehistoric use of Canyon live oaks as a human food source, the acorns are consumed by a variety of
wildlife as diverse asAcorn woodpecker ,California ground squirrel ,Dusky-Footed Woodrat ,Western harvest mouse andBlack-tailed deer . Surprisingly there seems little difference in food preference by wildlife among different oak species. [Peter G. Kennedy, "Post-dispersal seed predation varies by habitat not acorn size for Quercus chrysolepis" {"Fagaceae") and "Lithocarpus Densiflora" ("Fagaceae") in central coastal California", Madrono: Vol. 52, No. 1, pp. 30–34] .Extensive hybridization of Canyon live oaks has been documented with several other sympatric oak species, probably to a greater extent than for any other "Quercus" species. [Kevin C. Brown, "Biodiversity of Oak ("Quercus") Species in California and Adjacent Regions", Fifth Symposium on Oak Woodlands, San Diego, Ca., Oct. 22-25, 2001"] The ability of "Quercus chrysolepis" to compete with other dominant trees within its range has been analyzed from the standpoint of leafarchitecture and photosynthetic capability. The study results explain that, in low light environments, "Q. chrysolepis" out-competes species with superior leaf size and crown mass per unit volume by its greater photosynthetic efficiency and leaf lifespan. [J. C. Hunter, "Correspondence of environmental tolerances with leaf and branch attributes for six co-occurring species ofbroadleaf evergreen trees in northern California", Journal: Trees - Structure and Function, Volume 11, Number 3, Pages 169-175, January, 1997; Springer, Berlin / Heidelberg, ISSN 0931-1890]Canyon live oak gives functional habitat for many
fauna by providing perching, nesting, resting, or foraging sites for numerous species of birds, and shade and cover for diverse other mammals. Young "Q. chrysolepis" readily available browse. Canyon live oak woodlands serve as excellentmountain lion habitat because of the large population of deer frequenting these areas. Many species forage on Canyon live oak foliage includingblack-tailed jackrabbit ,beaver ,brush rabbit ,red-backed vole ,Sonoma chipmunk , cactus mouse,deer mouse , andporcupine .Pocket gopher s often feed on the cambium of young canyon live oaks.References
ee also
*
California oak woodland
*Riparian woodlandExternal links
* [http://www.ibiblio.org/pfaf/cgi-bin/arr_html?Quercus+chrysolepis "Quercus chrysolepis" fact sheet]
* [http://www.calflora.org/cgi-bin/species_query.cgi?where-taxon=Quercus+chrysolepis California distribution and taxon sheet]
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