Coast Live Oak

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Coast Live, sometimes called California Coastal Live Oak, is the most commonly seen oak in Glendale and along the California coast and foothills. It has made it's way into motion pictures by providing park-like groves often used in scenery shots for Hollywood movies.

CoastLiveOak_2727Glenoaks_SMIt's picturesque broad-canopied habit, evergreen leaves and gnarled growth habit make it one of the most popular single species of large trees used for landscaping and specimen plantings. Old trees can reach 100 feet in height, while most average 20-50 feet high and wide. It is interesting to note that crown spread can often exceed the trees height.

An example of a spectacular specimen is shown in the photo at the left. This notable giant is a city owned street tree and can be viewed at 2727 East Glenoaks Boulevard, located in the canyon. 

CoastLiveOak_BarnOwl_SMThe name, "live oak" comes from the distinction that this tree retains its green, live appearance during the winter months, when many other oaks may look lifeless due to their leafless appearance. Warmer, western climates make good habitats for these oaks and distribution of species is widespread in these areas.

Another benefit received from oak tree woodlands is habitat for birds of prey. Many hollow oak tree trunks serve as nests to barn owls. In return, owls keep a balanced check as natural rodent controllers. (photo © Dave Appleton, www.gobirding.eu

Leaves, Bark & Acorns

CoastLiveOak_Leaf_SMThe Coast Live oak has dark evergreen oval leaves that are shiny above with gray or rusty fuzz underneath. The hollylike appearance of the leaf is due to the spiny leaf margins. If you look at the leaf closely you will notice that the shape appears cupped, or spoon shaped as the leaf edges turn down to give it a distinctive style. This helps identify the Coast Live oak from its associated tree species, the Interior Live oak. Both of these species inhabit the same valley oak woodlands habitat and are often confused with each other.

CoastLiveOak_LichenOnTrunk_SMBark is smooth, graybrown when young. With age the bark develops broad, lighter gray ridges that contrasts with the darker brown mature bark. See photo at right.

CoastLiveOak_Acorns_SMThe wind-pollinated flowers appear in the spring, with male flowers appearing in long (2-4 inches) narrow, drooping catkins that are yellow-green in color; female flower are inconspicuous reddish green spikes that are found in the leaf axils.

The light brown acorns appear early in the fall and have an elongated, narrow shape. The caps are not warty, but have a smooth gray brown covering.

Oak Woodland Ecology

CoastLiveOak_brownGall_SMGalls or oak- apples, are quite common on Coast Live oaks. These trees provide a unique symbiotic relationship between plant and insect as gall wasps deposit eggs into the base of a vegetative bud. This activates the oak into producing a protective structure around the developing larvae. Exit holes are visible, indicating the wasp has fully developed and left the gall as a harmless remnant of their presence in the ecosystem.

The relationship between insect and plants is not unique in a healthy environment. Benefits are available when different species with similar needs live alongside one another. The same is true for companion, or understory plantings in the oak woodland. Plants found living together underneath oaks are making a contribution to both the oak trees and the surrounding habitat.

Douglas iris (see image below) and wild currents are found living together supporting plant life giving food and shelter to birds and small animals in the region.

CoastLiveOak_Iris_SMOaks continue to be part of California's natural history. They have been abundant in our landscape, however, due to the expanding urban populations, oak habitats are in decline. Long-term approaches to solving ecosystem problems while allowing development shows promise as integration of ecological, economical and social factors combine to maintain and enhance the quality of the environment.

Protect & Enjoy

Protecting our native trees requires our active partnership and contribution to the common goal of resource management. Oak, sycamore, and bay trees hold a unique place in our local ecosystem and provide habitat for 81 species of resident and migratory birds.

Urbanization continues to present a challenge within the sustainable capability of the ecosystem. Open spaces, clean air and homes for wildlife are worth protecting, but will demand support for the native trees existence in the local landscape.

Trees are living resources and assure healthy living habitats for interconnected flora and fauna, and the people that live within these habitats. To ensure that our trees will survive and thrive, please protect them by following these suggestions:

  • Do not injure the trunk with objects.
  • Keep all machines and weed whips away from tree trunks.
  • Practice conservative pruning.
  • Do not over water.