''Quercus chrysolepis'', commonly termed canyon live oak, canyon oak, golden cup oak or maul oak, is a North American

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, whic ...

oak that is found in Mexico and in the western United States, notably in the

California Coast Ranges The Coast Ranges of California span from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains. ...

. This tree is often found near creeks and drainage swales growing in moist cool

microhabitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s. 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.

Description

''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 A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from tree ...

. The trunk diameter typically ranges from . Exceptionally large specimens are found in the mountains of

Southern California Southern California (commonly shortened to SoCal) is a geographic and cultural region that generally comprises the southern portion of the U.S. state of California. It includes the Los Angeles metropolitan area, the second most populous urban ...

, and rank among the largest oaks in North America. The largest known in the

San Bernardino Mountains The San Bernardino Mountains are a high and rugged mountain range in Southern California in the United States. Situated north and northeast of San Bernardino and spanning two California counties, the range tops out at at San Gorgonio Mountain ...

measures high, with a trunk circumference of and a crown spread of . The elliptical to oblong

leaves A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, st ...

are 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 Glabrousness (from the Latin '' glaber'' meaning "bald", "hairless", "shaved", "smooth") is the technical term for a lack of hair, down, setae, trichomes or other such covering. A glabrous surface may be a natural characteristic of all or part of ...

the second year. The

bark Bark may refer to: * Bark (botany), an outer layer of a woody plant such as a tree or stick * Bark (sound), a vocalization of some animals (which is commonly the dog) Places * Bark, Germany * Bark, Warmian-Masurian Voivodeship, Poland Arts, e ...

of the canyon live oak is grayish brown, and rather smooth or sometimes scaly.

Acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera '' Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and b ...

s occur solitarily or in pairs, exhibiting lengths of 2–5 cm; these fruits are variable in size and shape, but generally

ovoid An oval () is a closed curve in a plane which resembles the outline of an egg. The term is not very specific, but in some areas ( projective geometry, technical drawing, etc.) it is given a more precise definition, which may include either o ...

, 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 A forest is an area of land dominated by trees. Hundreds of definitions of forest are used throughout the world, incorporating factors such as tree density, tree height, land use, legal standing, and ecological function. The United Nations' ...

communities in the

southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, N ...

. It is common in the mountainous regions of

California California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...

(

Sierra Nevada The Sierra Nevada () is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primar ...

Coast Ranges The Pacific Coast Ranges (officially gazetted as the Pacific Mountain System in the United States) are the series of mountain ranges that stretch along the West Coast of North America from Alaska south to Northern and Central Mexico. Although ...

Klamath Mountains The Klamath Mountains are a rugged and lightly populated mountain range in northwestern California and southwestern Oregon in the western United States. As a mountain system within both the greater Pacific Coast Ranges and the California Coast ...

, Cascades,

San Gabriel Mountains The San Gabriel Mountains ( es, Sierra de San Gabriel) are a mountain range located in northern Los Angeles County and western San Bernardino County, California, United States. The mountain range is part of the Transverse Ranges and lies betw ...

, etc.) with additional populations in the

Siskiyou Mountains The Siskiyou Mountains are a coastal subrange of the Klamath Mountains, and located in northwestern California and southwestern Oregon in the United States. They extend in an arc for approximately from east of Crescent City, California, nort ...

of southwestern

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, western

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

, northern

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

, southwestern

New Mexico ) , population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano) , seat = Santa Fe, New Mexico, Santa Fe , LargestCity = Albuquerque, New Mexico, Albuquerque , LargestMetro = Albuquerque metropolitan area, Tiguex , Offi ...

, and

Chihuahua Chihuahua may refer to: Places * Chihuahua (state), a Mexican state **Chihuahua (dog), a breed of dog named after the state **Chihuahua cheese, a type of cheese originating in the state **Chihuahua City, the capital city of the state **Chihuahua Mu ...

. 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 Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

types, including very rocky or cobbly environments. It is hardy to cold temperatures down to −11 °F, and will grow in neutral to moderately

acid In computer science, ACID ( atomicity, consistency, isolation, durability) is a set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps. In the context of databases, a se ...

ic 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 Sonoma County () is a county located in the U.S. state of California. As of the 2020 United States Census, its population was 488,863. Its county seat and largest city is Santa Rosa. It is to the north of Marin County and the south of Mendoci ...

. Canyon live oak grows at elevations of about 500 to 1,500 meters in southwestern Oregon; in

Northern California Northern California (colloquially known as NorCal) is a geographic and cultural region that generally comprises the northern portion of the U.S. state of California. Spanning the state's northernmost 48 counties, its main population centers incl ...

, 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 Rain is water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water f ...

, it occurs on south facing slopes, and in the hotter, drier parts of its distribution, on northerly slope faces.

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

data supports a much wider distribution throughout the

western United States The Western United States (also called the American West, the Far West, and the West) is the region comprising the westernmost states of the United States. As American settlement in the U.S. expanded westward, the meaning of the term ''the We ...

during the early

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

period.

Ecology

The species is often

sympatric In biology, two related species or populations are considered sympatric when they exist in the same geographic area and thus frequently encounter one another. An initially interbreeding population that splits into two or more distinct species s ...

with '' Quercus agrifolia'' and several other oak species. It is more

shade tolerant In ecology, shade tolerance is a plant's ability to tolerate low light levels. The term is also used in horticulture and landscaping, although in this context its use is sometimes imprecise, especially in labeling of plants for sale in commercial ...

than

Pacific madrone ''Arbutus menziesii'' or Pacific madrone (commonly madrone or madrona in the United States and arbutus in Canada), is a species of broadleaf evergreen tree in the family Ericaceae, native to the western coastal areas of North America, from Br ...

but not as much as the associated

Douglas-fir The Douglas fir (''Pseudotsuga menziesii'') is an evergreen conifer species in the pine family, Pinaceae. It is native to western North America and is also known as Douglas-fir, Douglas spruce, Oregon pine, and Columbian pine. There are three va ...

, 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 Drought tolerance is the ability to which a plant maintains its biomass production during arid or drought conditions. Some plants are naturally adapted to dry conditions'','' surviving with protection mechanisms such as desiccation tolerance, deto ...

. The acorns are consumed by a variety of

wildlife Wildlife refers to undomesticated animal species, but has come to include all organisms that grow or live wild in an area without being introduced by humans. Wildlife was also synonymous to game: those birds and mammals that were hunted ...

as diverse as acorn woodpecker,

California ground squirrel The California ground squirrel (''Otospermophilus beecheyi''), also known as the Beechey ground squirrel, is a common and easily observed ground squirrel of the western United States and the Baja California Peninsula; it is common in Oregon and ...

, dusky-footed wood rat,

western harvest mouse The western harvest mouse (''Reithrodontomys megalotis'') is a small neotomine mouse native to most of the western United States. Many authorities consider the endangered salt marsh harvest mouse to be a subspecies, but the two are now usually ...

and black-tailed deer. There seems to be little difference in food preference by wildlife among different oaks. Extensive

hybridization Hybridization (or hybridisation) may refer to: *Hybridization (biology), the process of combining different varieties of organisms to create a hybrid *Orbital hybridization, in chemistry, the mixing of atomic orbitals into new hybrid orbitals *Nu ...

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 Architecture is the art and technique of designing and building, as distinguished from the skills associated with construction. It is both the process and the product of sketching, conceiving, planning, designing, and constructing buildings ...

and

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in ...

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 of broadleaf

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 Fauna is all of the animal life present in a particular region or time. The corresponding term for plants is '' flora'', and for fungi, it is '' funga''. Flora, fauna, funga and other forms of life are collectively referred to as '' biota''. ...

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 Beavers are large, semiaquatic rodents in the genus ''Castor'' native to the temperate Northern Hemisphere. There are two extant species: the North American beaver (''Castor canadensis'') and the Eurasian beaver (''C. fiber''). Beavers a ...

brush rabbit The brush rabbit (''Sylvilagus bachmani''), or western brush rabbit, or Californian brush rabbit, is a species of cottontail rabbit found in western coastal regions of North America, from the Columbia River in Oregon to the southern tip of the ...

, red-backed vole,

Sonoma chipmunk The Sonoma chipmunk (''Neotamias sonomae'') is a species of rodent in the squirrel family Sciuridae. It is endemic to northwestern California in the United States. Members of Neotamias are characterized by having 2 premolars. ''N. sonomae'' has ...

cactus mouse The cactus mouse (''Peromyscus eremicus'') is a species of rodent in the family Cricetidae. It is a species of the genus ''Peromyscus'', a closely related group of New World mice often called "deermice" (although the term more commonly refers sp ...

, deer mouse, and

porcupine Porcupines are large rodents with coats of sharp spines, or quills, that protect them against predation. The term covers two families of animals: the Old World porcupines of family Hystricidae, and the New World porcupines of family, Erethiz ...

. 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''.

Allergenicity

The pollen of the canyon live oak is a severe allergen. Pollination occurs in spring.

Uses

Native Americans used the

acorn The acorn, or oaknut, is the nut of the oaks and their close relatives (genera '' Quercus'' and '' Lithocarpus'', in the family Fagaceae). It usually contains one seed (occasionally two seeds), enclosed in a tough, leathery shell, and b ...

s of this species as a food staple, after leaching the

tannin Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids. The term ''tannin'' (from Anglo-Norman ''tanner'' ...

s. Its roasted seed is also used as a

coffee substitute Coffee substitutes are non- coffee products, usually without caffeine, that are used to imitate coffee. Coffee substitutes can be used for medical, economic and religious reasons, or simply because coffee is not readily available. Roasted grain ...

. The wood is strong, being referred to as 'maul oak' by European-American settlers who employed it for sledgehammers and wedges. It is sometimes used in paneling and especially as firewood.

References

External links

*
Record Canyon Live Oaks of Southern California's Transverse Ranges
{{Taxonbar, from=Q138446

chrysolepis ''Chrysolepis'' is a small genus of plants in the family Fagaceae, endemic to the western United States. Its two species have the common name chinquapin. The genus occurs from western Washington south to the Transverse Ranges in Southern Calif ...

Trees of Northwestern Mexico Trees of the Western United States Trees of the Southwestern United States Flora of California Flora of the Klamath Mountains Flora of the Sierra Nevada (United States) Natural history of the California chaparral and woodlands Natural history of the California Coast Ranges Natural history of the Channel Islands of California Natural history of the Peninsular Ranges Natural history of the San Francisco Bay Area Natural history of the Santa Monica Mountains Natural history of the Transverse Ranges Trees of mild maritime climate Trees of Mediterranean climate Plants described in 1854 Taxa named by Albert Kellogg Garden plants of North America Drought-tolerant trees Ornamental trees Oaks of Mexico