Quercus agrifolia

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Coast Live Oak
)

Coast live oak
Coast live oak foliage with new spring growth

Secure  (NatureServe)[1]
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fagales
Family: Fagaceae
Genus: Quercus
Subgenus: Quercus subg. Quercus
Section:
Quercus sect. Lobatae
Species:
Q. agrifolia
Binomial name
Quercus agrifolia
Natural range
Synonyms[2]
List
  • Quercus acroglandis Kellogg
  • Quercus acutiglandis Sarg.
  • Quercus agrifolia var. frutescens Engelm.
  • Quercus agrifolia var. oxyadenia (Torr.) J.T.Howell
  • Quercus oxyadenia Torr.
  • Quercus pricei Sudw.

Quercus agrifolia, the California live oak,

red oak section of oaks (Quercus sect. Lobatae).[6]

This species is commonly

spinose leaves
are superficially similar.

Description

Coast live oak typically has a much-branched trunk and reaches a mature height of 10–25 metres (33–82 feet). Some specimens may attain an age exceeding 1,000 years. Examples of this include the Grand Oak of Cherry Valley, California,[7] the Encino Oak Tree, which died in the 1990s (part of the stump has been preserved)[8] and the Pechanga Great Oak.[9]

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.[6] The oldest specimens might exceed 6 m (20 ft) in trunk circumference and 30 m (100 ft) in height.[9][10]

The

photosynthetic cells.[6]

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.[6] The leaf shape may be also useful as condensation surfaces for "dew and mist, which would allow the tree to survive years with limited rainfall".[11]

The flowers are produced in early-to-mid spring; the male flowers are pendulous catkins 5–10 cm (2–4 in) long, the female flowers inconspicuous, less than 0.5 cm (1⁄4 in) long, with 1–3 clustered together. The fruit is a slender reddish brown acorn 2–3.5 cm (3⁄4–1+1⁄2 in) long and 1–1.5 cm (3⁄8–5⁄8 in) 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).[6]

  • Coast live oak, Sonoma County
    Coast live oak, Sonoma County
  • Acorns and leaves
    Acorns and leaves

Recognized varieties

There are two varieties of Quercus agrifolia:

Image Scientific name Description Distribution
Quercus agrifolia var. agrifolia Leaves that are glabrous to slightly hairy on the abaxial side, especially near the leaf vein axils. Hybrids with Q. kelloggii, Q. parvula var. shevei, and Q. wislizeni are known. Throughout the range of the species.
Quercus agrifolia var. oxyadenia Leaves that are
tomentose
abaxially, with densely interwoven hairs. It prefers granitic soils; hybrids with Q. kelloggii known.		 Southwesternmost California (San Diego area), Baja California.

Hybridity

Several hybrids between coast live oak and other red oak species have been documented. Hybrids with

Shreve oak (Q. parvula var. shrevei). All these oak species show evidence of introgression
with one another.

Etymology

In naming the species, Née compared it to a species illustrated in Leonard Plukenet's Phytographia under the descriptive name "Ilex folio agrifolii americana, forte agria, vel aquifolia glandifera" which Plukenet had compared, in his Almagestum botanicum, to Luigi Anguillara's Agrifolia glandifera, the noun 'Agrifolia' being a Medieval Latin form of 'Aquifolium' meaning a holly or holly-leaved oak, and related to the Modern Italian 'Agrifoglio,' meaning 'holly.'[12][13][14]

Distribution and habitat

Tree growing by a roadside in California
Coast live oak, San Luis Obispo County, California

Normally the tree is found on well-drained soils of coastal hills and plains, often near year-round or

valley oak woodland and both northern and southern mixed evergreen forests. While normally found within 100 kilometers (62 miles) of the Pacific Ocean
at elevations less than 700 m (2,300 ft), in southern California it occasionally occurs at up to 1,500 m (4,900 ft) in elevation.

It is the only California native oak that 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

western poison-oak
.

Ecology

lace lichen, acorn woodpecker

The California oak moth (

Chionodes vanduzeei caterpillars
.

Live oak trees, among other western oaks, are also known to support acorn woodpeckers, which store their acorns in tree trunks and remove them when they want to eat. [16]

Allergenicity

The pollen of the coast live oak is a severe allergen. Pollination occurs in spring.[17]

Uses

Historical

Coast live oak at Rancho Los Encinos in the San Fernando Valley

At least twelve distinct cultures of Native Americans are known to have consumed the acorns as a dietary staple.[citation needed] The seeds were ground into meal, which after being washed was boiled into mush or baked in ashes to make bread.[18] In the 18th century, Spaniards in the San Fernando Valley used the wood for charcoal to fire kilns 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

landscape painters
throughout California modern history since the mid-19th century.

Modern

Coast live oak has also become a common addition to western US landscaping. 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 to avoid regular watering within the oak's

sudden oak death.[19]

Culture

The coast live oak, especially in its

San Diego, and Encinal del Temescal, now the city of Oakland.[20]

Paso Robles
(fully 'El Paso de Robles' or 'Pass of the Oaks') also refers to the ubiquitous live oaks in the region as a geographical place name.

References

  1. doi:10.2305/IUCN.UK.2016-1.RLTS.T194049A2295175.en
    . Retrieved 12 November 2021.
  2. ^ "Quercus agrifolia Née". World Checklist of Selected Plant Families. Royal Botanic Gardens, Kew – via The Plant List. Note that this website has been superseded by World Flora Online
  3. ^ USDA, NRCS (n.d.). "Quercus agrifolia". The PLANTS Database (plants.usda.gov). Greensboro, North Carolina: National Plant Data Team. Retrieved 30 July 2015.
  4. OCLC 277201819.{{cite book}}: CS1 maint: location missing publisher (link
    )
  5. ^ "Quercus agrifolia". Calflora. Berkeley, California: The Calflora Database.
  6. ^ a b c d e Nixon, Kevin C. (1997). "Quercus agrifolia". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 3. New York and Oxford: Oxford University Press – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  7. ^ "Coast live oak 'The Grand Oak' at Highland Springs Resort, Cherry Valley, California, United States".
  8. ^ "Grand Old Tree: Lang Oak Praised on Arbor Day", Daily News, Los Angeles, March 8, 1997
  9. ^ a b "Pechanga Band of Luiseño Indians – the Great Oak".
  10. ^ "The Great Encino Oak Tree".
  11. ^ "Coastal live oak - Quercus agrifolia". Santa Monica Mountains Trails Council. Retrieved 2023-11-10.
  12. ^ Née, Luis. Descripción de varias especies nuevas de 'Encina ' (Quercus de Linneo). Anales de historia natural. volume 3. 1801.[1]
  13. ^ Plukenet, Leonard. Phytographia [...] Pars tertia, 1692 [2]
  14. ^ Plukenet, Leonard. Almagestum botanicum, 1696
  15. ^ "Quercus (Oak) Notes – Trees of Stanford & Environs". trees.stanford.edu.
  16. ^ "An Enduring Oak Mystery: Synchronized Acorn Booms".
  17. ^ "Coastal Live Oak (Quercus agrifolia) Species Details and Allergy Info, Santa clara county, California".
  18. ISBN 0394731271
    .
  19. ^ J. M. Davidson (7 July 2003). "Sudden Oak Death and Associated Diseases Caused by Phytophthora ramorum". Plant Management Network. Retrieved 12 January 2010.
  20. ISBN 0520213165
    , pp. 123–124

Bibliography

External links

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