Coast Live Oak
Encyclopedia
Quercus agrifolia, the Coast Live Oak, is an evergreen
oak
(highly variable and often shrubby), native to the California Floristic Province
. It grows west of the Sierra Nevada from Mendocino County
, California
, south to northern Baja California
in Mexico
. It is classified in the red oak section (Quercus sect. Lobatae).
This species is commonly sympatric with Canyon Live Oak
, and the two may be hard to distinguish because their spinose leaves are superficially similar.
estate in San Mateo County
.
The trunk, particularly for older individuals, may be highly contorted, massive and gnarled. The crown is broadly rounded and dense, especially when aged 20 to 70 years; in later life the trunk and branches are more well defined and the leaf density lower.
are dark green, oval, often convex in shape, 2–7 cm long and 1–4 cm broad; the leaf margin is spiny-toothed (spinose), with sharp thistly fibers that extend from the lateral leaf veins. The outer layers of leaves are designed for maximum solar
absorption, containing two to three layers of photosynthetic cells.
These outer leaves are deemed to be small in size to more efficiently re-radiate the heat gained from solar capture. Shaded leaves are generally broader and thinner, having only a single layer of photosynthetic cells. The convex leaf shape may be useful for interior leaves which depend on capturing reflected light scattered in random directions from the outer canopy.
s are produced in early-to-mid spring; the male flowers are pendulous catkin
s 5–10 cm long, the female flowers inconspicuous, less than 0.5 cm long, with 1-3 clustered together. The fruit
is a slender reddish brown acorn
2-3.5 cm long and 1-1.5 cm broad, with the basal quarter enclosed in a cupule
; unusually for a red oak, the acorns mature about 7–8 months after pollination (most red oak acorns take 18 months to mature).
of Quercus agrifolia:
(Q. wislizenii) are known in many areas in northern California. Coast live oak also hybridizes with Nuttall's Scrub Oak (Q. dumosa) and Shreve Oak (Q. parvula var. shrevii). All these oak species show evidence of introgression
with one another.
It is the dominant overstory plant of the Coast Live Oak woodland
habitat, often joined by California Bay Laurel
and California Buckeye
north of Big Sur
. Associated understory plants include Toyon
, various manzanita
s and Western Poison-oak
.
Normally the tree is found on well drained soils of coastal hills and plains, often near year round or perennial stream
s. It may be found in several natural communities including Coast Live Oak woodland, Engelmann Oak
woodland, Valley Oak
woodland and both northern and southern mixed evergreen forests. While normally found within 100 kilometers of the Pacific Ocean
at elevations less than 700 meters, in southern California it occasionally occurs at up to 1,500 meters in altitude.
The California Oak Moth (Phryganidia californica
) caterpillar subsists entirely on living and fallen leaves of the Coast Live Oak. In 8-10 year cycles, the caterpillar will appear in sufficient abundance to denude healthy trees. The trees recover, and botanists speculate that the species provide mutual benefit, possibly in the form of fertilizer for the oak http://trees.stanford.edu/ENCYC/QUERCUS.htm. The Coast Live Oak is also the only known foodplant of Chionodes vanduzeei caterpillar
s.
are known to have consumed the acorns as a dietary staple. In the 18th century Spaniards
in the San Fernando Valley
used the wood for charcoal to fire kiln
s in making adobe
. Later this form of charcoal would be utilized in the baking, gunpowder
and electric power
industries.
In the 18th and 19th centuries shipbuilders sought out the odd angular branches to make special joints. Pioneer
s moving west would harvest small amounts for making farm implements and wagon wheels, but the greatest impact was the wholesale clearing of oak woodlands to erect sprawling cities such as San Diego and San Francisco. The irregular shape often let the tree escape widespread harvest for building timbers, and also led the early settlers to endow the Coast Live Oak with mystical qualities. Its stateliness has made it a subject of historical landscape painter
s throughout California modern history since the mid-19th century.
. It is however sensitive to changes in grading and drainage; in particular, it is important to respect the root crown level and avoid adding soil near the trunk when construction or landscaping
occurs.
Also, if incorporating it into a landscaping scheme with artificial irrigation, it is important not to water within the oak's drip line
(canopy), as wet soil in the summer increases infection rates by soil-borne Phytophthora
diseases like sudden oak death
.
forms encino or encina, encinitas "little oaks", and encinal "oak grove", gave its name to seven land grants across California and to many communitities and geographic features.
These include Rancho Los Encinos
, the community of Encino
near Los Angeles, Encinitas
near San Diego
, and Encinal del Temescal, now the city of Oakland
.
Paso Robles ('Pass of the Oaks') also refers to oaks as a geographical place name.
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
oak
Oak
An oak is a tree or shrub in the genus Quercus , of which about 600 species exist. "Oak" may also appear in the names of species in related genera, notably Lithocarpus...
(highly variable and often shrubby), native to the California Floristic Province
California Floristic Province
The California Floristic Province is a floristic province with a Mediterranean climate located on the Pacific Coast of North America with a distinctive flora that bears similarities to floras found in other regions experiencing a winter rainfall, summer drought climate like the Mediterranean...
. It grows west of the Sierra Nevada from Mendocino County
Mendocino County, California
Mendocino County is a county located on the north coast of the U.S. state of California, north of the greater San Francisco Bay Area and west of the Central Valley. As of the 2010 census, the population was 87,841, up from 86,265 at the 2000 census...
, California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, south to northern Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...
in Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. It is classified in the red oak section (Quercus sect. Lobatae).
This species is commonly sympatric with Canyon Live Oak
Quercus chrysolepis
Quercus chrysolepis, commonly termed Canyon Live Oak, or Golden Cup Oak, is a species of evergreen oak that is found in the southwestern part of North America, notably in the California Coast Ranges. This tree is often found near creeks and drainage swales growing in moist cool microhabitats...
, and the two may be hard to distinguish because their spinose leaves are superficially similar.
Description
Coast Live Oak typically has a much-branched trunk and reaches a mature height of 10–25 meters. Some specimens may attain an age exceeding 250 years, with trunk diameters up to three or four meters, such as the magnificent specimens on the FiloliFiloli
Filoli is a country house set in of formal gardens surrounded by estate, located in Woodside, California, about 25 miles south of San Francisco, at the southern end of Crystal Springs Lake, on the eastern slope of the Santa Cruz Mountains....
estate in San Mateo County
San Mateo County, California
San Mateo County is a county located in the San Francisco Bay Area of the U.S. state of California. It covers most of the San Francisco Peninsula just south of San Francisco, and north of Santa Clara County. San Francisco International Airport is located at the northern end of the county, and...
.
The trunk, particularly for older individuals, may be highly contorted, massive and gnarled. The crown is broadly rounded and dense, especially when aged 20 to 70 years; in later life the trunk and branches are more well defined and the leaf density lower.
Leaves
The leavesLeaf
A leaf is an organ of a vascular plant, as defined in botanical terms, and in particular in plant morphology. Foliage is a mass noun that refers to leaves as a feature of plants....
are dark green, oval, often convex in shape, 2–7 cm long and 1–4 cm broad; the leaf margin is spiny-toothed (spinose), with sharp thistly fibers that extend from the lateral leaf veins. The outer layers of leaves are designed for maximum solar
Sun
The Sun is the star at the center of the Solar System. It is almost perfectly spherical and consists of hot plasma interwoven with magnetic fields...
absorption, containing two to three layers of photosynthetic cells.
These outer leaves are deemed to be small in size to more efficiently re-radiate the heat gained from solar capture. Shaded leaves are generally broader and thinner, having only a single layer of photosynthetic cells. The convex leaf shape may be useful for interior leaves which depend on capturing reflected light scattered in random directions from the outer canopy.
Inflorescence and acorns
The flowerFlower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s are produced in early-to-mid spring; the male flowers are pendulous catkin
Catkin
A catkin or ament is a slim, cylindrical flower cluster, with inconspicuous or no petals, usually wind-pollinated but sometimes insect pollinated . They contain many, usually unisexual flowers, arranged closely along a central stem which is often drooping...
s 5–10 cm long, the female flowers inconspicuous, less than 0.5 cm long, with 1-3 clustered together. The fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
is a slender reddish brown acorn
Acorn
The acorn, or oak nut, is the nut of the oaks and their close relatives . It usually contains a single seed , enclosed in a tough, leathery shell, and borne in a cup-shaped cupule. Acorns vary from 1–6 cm long and 0.8–4 cm broad...
2-3.5 cm long and 1-1.5 cm broad, with the basal quarter enclosed in a cupule
Cupule
The calybium and the cupule make up the accessory fruit of flowering plants in the family Fagaceae. These two parts derive from different flower components....
; unusually for a red oak, the acorns mature about 7–8 months after pollination (most red oak acorns take 18 months to mature).
Recognized varieties
There are two varietiesVariety (biology)
In botanical nomenclature, variety is a taxonomic rank below that of species: as such, it gets a three-part infraspecific name....
of Quercus agrifolia:
- Quercus agrifolia var. agrifolia. Throughout the range of the species. Leaves that are glabrous to slightly hairy on the abaxial side, especially near the leaf vein axils. Hybrids with Q. kelloggii, Quercus parvula var. shevei, and Q. wislizenii are known.
- Quercus agrifolia var. oxyadenia. Southwesternmost California (San Diego area), Baja California. Leaves that are tomentose abaxially, with densely interwoven hairs. It prefers granitic soils; hybrids with Q. kelloggii known.
Hybridity
Several hybrids between Coast Live Oak and other red oak species have been documented. Hybrids with Interior Live OakInterior Live Oak
Quercus wislizeni, known by the common names Interior Live Oak, and Sierra Live Oak, is an evergeen oak, highly variable and often shrubby, found in areas of California in the United States. It also occurs south into northern Baja California in Mexico...
(Q. wislizenii) are known in many areas in northern California. Coast live oak also hybridizes with Nuttall's Scrub Oak (Q. dumosa) and Shreve Oak (Q. parvula var. shrevii). All these oak species show evidence of introgression
Introgression
Introgression, also known as introgressive hybridization, in genetics is the movement of a gene from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species...
with one another.
Etymology
The name Quercus agrifolia literally means "sharp-leaved oak", not "field-leaved oak" as is sometimes thought, nor is it an error by the describing botanist for "aquifolia", "holly-leaved". This species is sometimes known by the name "California Live Oak".Habitat and ecology
Coast Live Oak is the only California native oak that actually thrives in the coastal environment, although it is rare on the immediate shore; it enjoys the mild winter and summer climate afforded by ocean proximity, and it is somewhat tolerant of aerosol-borne sea salt. The coastal fog supplies relief from the rainless California summer heat.It is the dominant overstory plant of the Coast Live Oak woodland
Woodland
Ecologically, a woodland is a low-density forest forming open habitats with plenty of sunlight and limited shade. Woodlands may support an understory of shrubs and herbaceous plants including grasses. Woodland may form a transition to shrubland under drier conditions or during early stages of...
habitat, often joined by California Bay Laurel
Umbellularia
Umbellularia californica is a large tree native to coastal forests of California and slightly extended into Oregon.It is the sole species in the genus Umbellularia....
and California Buckeye
Aesculus californica
Aesculus californica is a species of buckeye that is native [ |] to California and southwest Oregon [Jackson, County], and the only buckeye native to these states.-Description:...
north of Big Sur
Big Sur
Big Sur is a sparsely populated region of the Central Coast of California where the Santa Lucia Mountains rise abruptly from the Pacific Ocean. The name "Big Sur" is derived from the original Spanish-language "el sur grande", meaning "the big south", or from "el país grande del sur", "the big...
. Associated understory plants include Toyon
Toyon
Heteromeles arbutifolia , and commonly known as Toyon, is a common perennial shrub native to California down to Baja California....
, various manzanita
Manzanita
Manzanita is a common name for many species of the genus Arctostaphylos. They are evergreen shrubs or small trees present in the chaparral biome of western North America, where they occur from southern British Columbia, Washington to California, Arizona and New Mexico in the United States, and...
s and Western Poison-oak
Western Poison-oak
Toxicodendron diversilobum, western poison oak or Pacific poison-oak is in the Anacardiaceae family and is a plant best known for its ability to cause allergic rashes after contact...
.
Normally the tree is found on well drained soils of coastal hills and plains, often near year round or perennial stream
Perennial stream
A perennial stream or perennial river is a stream or river that has continuous flow in parts of its bed all year round during years of normal rainfall. "Perennial" streams are contrasted with "intermittent" streams which normally cease flowing for weeks or months each year, and with "ephemeral"...
s. It may be found in several natural communities including Coast Live Oak woodland, Engelmann Oak
Engelmann Oak
Quercus engelmannii, the Engelmann Oak or Pasadena Oak, is a species of oak in the white oak section Quercus sect. Quercus, native to Southern California and northwestern Baja California, Mexico.-Description:...
woodland, Valley Oak
Valley Oak
Quercus lobata, commonly called the Valley oak, grows into the largest of North American oaks. It is endemic to California, growing in the interior valleys and foothills. Mature specimens may attain an age of up to 600 years. This deciduous oak requires year-round access to groundwater.Its thick,...
woodland and both northern and southern mixed evergreen forests. While normally found within 100 kilometers of the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
at elevations less than 700 meters, in southern California it occasionally occurs at up to 1,500 meters in altitude.
The California Oak Moth (Phryganidia californica
Phryganidia californica
The California Oakworm or California Oak Moth is a moth of the Notodontidae family. It is found along the coasts of California and Oregon.The wingspan is about 30 mm. They are tan to gray moths with prominent wing veins....
) caterpillar subsists entirely on living and fallen leaves of the Coast Live Oak. In 8-10 year cycles, the caterpillar will appear in sufficient abundance to denude healthy trees. The trees recover, and botanists speculate that the species provide mutual benefit, possibly in the form of fertilizer for the oak http://trees.stanford.edu/ENCYC/QUERCUS.htm. The Coast Live Oak is also the only known foodplant of Chionodes vanduzeei caterpillar
Caterpillar
Caterpillars are the larval form of members of the order Lepidoptera . They are mostly herbivorous in food habit, although some species are insectivorous. Caterpillars are voracious feeders and many of them are considered to be pests in agriculture...
s.
Historical usage
At least twelve distinct cultures of Native AmericansNative Americans in the United States
Native Americans in the United States are the indigenous peoples in North America within the boundaries of the present-day continental United States, parts of Alaska, and the island state of Hawaii. They are composed of numerous, distinct tribes, states, and ethnic groups, many of which survive as...
are known to have consumed the acorns as a dietary staple. In the 18th century Spaniards
Spanish colonization of the Americas
Colonial expansion under the Spanish Empire was initiated by the Spanish conquistadores and developed by the Monarchy of Spain through its administrators and missionaries. The motivations for colonial expansion were trade and the spread of the Christian faith through indigenous conversions...
in the San Fernando Valley
San Fernando Valley
The San Fernando Valley is an urbanized valley located in the Los Angeles metropolitan area of southern California, United States, defined by the dramatic mountains of the Transverse Ranges circling it...
used the wood for charcoal to fire kiln
Kiln
A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced. Uses include the hardening, burning or drying of materials...
s in making adobe
Adobe
Adobe is a natural building material made from sand, clay, water, and some kind of fibrous or organic material , which the builders shape into bricks using frames and dry in the sun. Adobe buildings are similar to cob and mudbrick buildings. Adobe structures are extremely durable, and account for...
. Later this form of charcoal would be utilized in the baking, gunpowder
Gunpowder
Gunpowder, also known since in the late 19th century as black powder, was the first chemical explosive and the only one known until the mid 1800s. It is a mixture of sulfur, charcoal, and potassium nitrate - with the sulfur and charcoal acting as fuels, while the saltpeter works as an oxidizer...
and electric power
Electric power
Electric power is the rate at which electric energy is transferred by an electric circuit. The SI unit of power is the watt.-Circuits:Electric power, like mechanical power, is represented by the letter P in electrical equations...
industries.
In the 18th and 19th centuries shipbuilders sought out the odd angular branches to make special joints. Pioneer
Settler
A settler is a person who has migrated to an area and established permanent residence there, often to colonize the area. Settlers are generally people who take up residence on land and cultivate it, as opposed to nomads...
s moving west would harvest small amounts for making farm implements and wagon wheels, but the greatest impact was the wholesale clearing of oak woodlands to erect sprawling cities such as San Diego and San Francisco. The irregular shape often let the tree escape widespread harvest for building timbers, and also led the early settlers to endow the Coast Live Oak with mystical qualities. Its stateliness has made it a subject of historical landscape painter
Landscape art
Landscape art is a term that covers the depiction of natural scenery such as mountains, valleys, trees, rivers, and forests, and especially art where the main subject is a wide view, with its elements arranged into a coherent composition. In other works landscape backgrounds for figures can still...
s throughout California modern history since the mid-19th century.
Modern usage
Coast Live Oak has also become a common addition to landscapingLandscaping
Landscaping refers to any activity that modifies the visible features of an area of land, including:# living elements, such as flora or fauna; or what is commonly referred to as gardening, the art and craft of growing plants with a goal of creating a beautiful environment within the landscape.#...
. It is however sensitive to changes in grading and drainage; in particular, it is important to respect the root crown level and avoid adding soil near the trunk when construction or landscaping
Landscaping
Landscaping refers to any activity that modifies the visible features of an area of land, including:# living elements, such as flora or fauna; or what is commonly referred to as gardening, the art and craft of growing plants with a goal of creating a beautiful environment within the landscape.#...
occurs.
Also, if incorporating it into a landscaping scheme with artificial irrigation, it is important not to water within the oak's drip line
Drip line
Drip line may refer to:* Neutron drip line* Proton drip line* Tree drip line, the area defined by the outermost circumference of a tree canopy where water drips from and onto the ground* Drip irrigation line, where the tubes and hoses are laid-See also:...
(canopy), as wet soil in the summer increases infection rates by soil-borne Phytophthora
Phytophthora
Phytophthora is a genus of plant-damaging Oomycetes , whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. The genus was first described by Heinrich Anton de Bary in 1875...
diseases like sudden oak death
Sudden oak death
Sudden Oak Death is the common name of a disease caused by the oomycete plant pathogen Phytophthora ramorum. The disease kills oak and other species of tree and has had devastating effects on the oak populations in California and Oregon as well as also being present in Europe...
.
Geographical monikers
The Coast Live Oak, especially in its SpanishSpanish language
Spanish , also known as Castilian , is a Romance language in the Ibero-Romance group that evolved from several languages and dialects in central-northern Iberia around the 9th century and gradually spread with the expansion of the Kingdom of Castile into central and southern Iberia during the...
forms encino or encina, encinitas "little oaks", and encinal "oak grove", gave its name to seven land grants across California and to many communitities and geographic features.
These include Rancho Los Encinos
Rancho Los Encinos
Rancho Los Encinos was a Spanish grazing concession, and later Mexican land granted cattle and sheep rancho and travelers way-station on the El Camino Real in the San Fernando Valley, in present day Encino, Los Angeles County, California...
, the community of Encino
Encino, Los Angeles, California
Encino is a hilly district of the city of Los Angeles, California, United States. Specifically, it is located in the central portion of the southern San Fernando Valley and on the north slope of the Santa Monica Mountains...
near Los Angeles, Encinitas
Encinitas, California
Encinitas is a coastal beach city in San Diego County, California. Located within Southern California, it is approximately north of San Diego in North County and about south of Los Angeles. As of the 2010 census, the city had a population of 59,518, up from 58,014 at the 2000 census. Encinitas is...
near San Diego
San Diego, California
San Diego is the eighth-largest city in the United States and second-largest city in California. The city is located on the coast of the Pacific Ocean in Southern California, immediately adjacent to the Mexican border. The birthplace of California, San Diego is known for its mild year-round...
, and Encinal del Temescal, now the city of Oakland
Oakland, California
Oakland is a major West Coast port city on San Francisco Bay in the U.S. state of California. It is the eighth-largest city in the state with a 2010 population of 390,724...
.
Paso Robles ('Pass of the Oaks') also refers to oaks as a geographical place name.