|Leaves and acorns|
|Subgenus:||Quercus subg. Quercus|
|Section:||Quercus sect. Protobalanus|
|Natural range of Quercus chrysolepis|
Quercus chrysolepis, commonly termed canyon live oak, canyon oak, golden cup oak or maul oak, is a North American species of evergreen oak that is found in Mexico and in the western United States, notably in the California 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 identification arises from the leaves of canyon live oak being geometrically flat.
Quercus chrysolepis is an evergreen tree with significant-sized spreading, horizontal branches, and a broad, rounded crown; it attains a height of 6–30 meters (20–100 feet) and often forms as a shrub. The trunk diameter typically ranges from 30 to 100 centimeters (12 to 39 inches). Exceptionally large specimens are found in the mountains of Southern California, and rank among the largest oaks in North America. The largest known in the San Bernardino Mountains measures 38 m (124 ft) high, with a trunk circumference of 12 m (39 ft 4 in) and a crown spread of 30 m (98 ft).
The elliptical to oblong leaves are 2.5 to 8 cm (1 to 3+1⁄4 in) in length and about half as wide; they are short-pointed at the tip, and 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, often becoming gray and nearly glabrous the second year.
The bark of the canyon live oak is grayish brown, and rather smooth or sometimes scaly. Acorns occur solitarily or in pairs, exhibiting lengths of 2–5 cm; these fruits are variable in size and shape, but generally ovoid, turban-like with a shallow, thick cup of scales densely covered with yellowish hairs; the stalk is barely evident.
Distribution and habitat
Q. chrysolepis is found in a variety of forest communities in the southwestern United States. It is common in the mountainous regions of California (Sierra Nevada, Coast Ranges, Klamath Mountains, Cascades, San Gabriel Mountains, etc.) with additional populations in the Siskiyou Mountains of southwestern Oregon, western Nevada, northern Baja California, Arizona, southwestern New Mexico, and Chihuahua. Southwestern New Mexico population are most likely the result of introgression from Quercus palmeri to Q. chrysolepis. Those populations tend to be intermediate in overall morphology, but all lack the diagnostic trichomes and biochemical markers of Q. palmeri; they are best classified as Q. chrysolepis affinity Q. palmer.
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 moderately acidic soils with pH ranges of 4.5 to 7.5. An example of very rocky and serpentine soil tolerance is the species occurrence at the Cedars of Sonoma County, California. Canyon live oak grows at elevations of about 500 to 1,500 meters in southwestern Oregon; in Northern California, from 100 to 1,400 meters; and in Southern California, up to approximately 2,700 meters. Q. chrysolepis can be the dominant tree on steep canyon walls, especially in locations of shallow rocky soils. In areas of moderate to high rainfall, it occurs on south facing slopes, and in the hotter, drier parts of its distribution, on northerly slope faces.
The species is often sympatric with Quercus agrifolia and several other oak species. It is more shade tolerant than Pacific madrone but not as much as the associated Douglas-fir, tanoak, and golden chinkapin. After forest fires, canyon live oak regenerates vigorously by basal sprouting, and the clonal diversity of this species has been shown to be high. It is typically succeeded by other species except in more extreme dry and rocky climates, being exceptionally drought tolerant.
The acorns are consumed by a variety of wildlife as diverse as acorn woodpecker, California ground squirrel, dusky-footed wood rat, western harvest mouse and black-tailed deer. There seems to be little difference in food preference by wildlife among different oaks. Extensive hybridization of Q. chrysolepis has been documented with several other sympatric oak species, probably to a greater extent than for any other Quercus species. The ability of Q. chrysolepis to compete with other dominant trees within its range has been analyzed from the standpoint of leaf architecture 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.
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 is a readily available browse. Canyon live oak woodlands serve as excellent mountain lion habitat because of the large population of deer frequenting these areas. Many species forage on canyon live oak foliage including black-tailed jackrabbit, beaver, brush rabbit, red-backed vole, Sonoma chipmunk, cactus mouse, deer mouse, and porcupine. Pocket gophers often feed on the cambium of young canyon live oaks.
In southern California Q. chrysolepis is the food plant of a small moth, Neocrania bifasciata.
The pollen of the canyon live oak is a severe allergen. Pollination occurs in spring.
- Beckman, E. (2016). "Quercus chrysolepis". IUCN Red List of Threatened Species. 2016: e.T194076A2296502. doi:10.2305/IUCN.UK.2016-1.RLTS.T194076A2296502.en. Retrieved 12 November 2021.
- "Quercus chrysolepis Liebm.". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew – via The Plant List.
- Arno, Stephen F.; Hammerly, Ramona P. (2020) . Northwest Trees: Identifying & Understanding the Region's Native Trees (field guide ed.). Seattle: Mountaineers Books. pp. 239–241. ISBN 978-1-68051-329-5. OCLC 1141235469.
- "Canyon live Oak (Quercus chrysolepis)". 4 January 2017.
- Bruce M. Pavlik, Pamela C. Muick, Sharon Johnson and Marjorie Popper, Oaks of California, Cachuma Press (1992) ISBN 0-9628505-1-9
- Nixon, Kevin C. (1997). "Quercus chrysolepis". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 3. New York and Oxford – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
- "Quercus chrysolepis". Calflora. Berkeley, California: The Calflora Database.
- "Quercus chrysolepis". County-level distribution map from the North American Plant Atlas (NAPA). Biota of North America Program (BONAP). 2014.
- SEINet, Southwestern Biodiversity, Arizona chapter
- J. M. Tucker and H. S. Haskell 1960
- "Quercus palmeri in Flora of North America @". Efloras.org. Retrieved 2022-05-01.
- C.Michael Hogan. 2010. Leather oak. eds. Mark McGinley & C.J.Cleveland. Encyclopedia of Earth. National Council for Science and the Environment. Washington DC Archived July 16, 2011, at the Wayback Machine
- McDonald, Philip M., and Edward E. Littrell, 1976. The bigcone Douglas-fir-canyon live oak community in southern California, Madroño 23:310–320
- 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)
- 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
- 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
- J. C. Hunter, Correspondence of environmental tolerances with leaf and branch attributes for six co-occurring species of broadleaf 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 (Quercus chrysolepis) Species Details and Allergy Info, Santa clara county, California".