Coast live oak woodlands are restricted to coastal areas from Sonoma County south into Baja California.  They are one of the most characteristic and picturesque plant communities along California's central and southern coastal areas, although most are gone from southern California due to urbanization.  In the central coast, coast live oaks dominant the oak woodland along the immediate coast where they often occur in pure stands.  In the interior ares where conditions are more hot and dry, coast live oaks become part of the foothill woodland and mix with blue oak, valley oak, and foothill pine.  However, in these areas coast live oaks occupy the most mesic environments of the foothill woodland communities.  Quercus agrifolia (coast live oak) is an evergreen black oak while blue oak and valley oak are deciduous.

In coast live oak woodland varies in terms of physiognomy and density over its range.  In mesic areas such as canyons and north facing slopes, these communities form a dense canopy cover with little or no understory vegetation.  In drier, more exposed areas, coast live oaks are more scattered forming an open woodland with a grassland understory.  However,  understory vegetation in these woodlands varies significantly depending on  topography and the surrounding vegetation.

Coastal Live Oak Woodland is one of the most characteristic and interesting vegetation types in Poly Canyon and the surrounding watershed.  On these hillsides, the coast live oak woodland is typically composed of pure stands of Quercus agrifolia (coast live oak) although a few Umbellularia californica (California bay-laurel) are present.  Heteromeles arbutifolia (toyon) is also common and sometimes attains the size of small oaks.

Coastal live oak woodland is considered the climax vegetation type for the climate along the central coast including Poly Canyon.  In Poly Canyon it characteristically occupies the most mesic slopes and canyon areas.  Because of the heterogeneity of the habitats on these hillsides, the coastal live oak woodlands integrate with grassland in the valley and with coastal scrub and chaparral (on steep slopes with rocky, gravelly, dry soils).  Coast live oaks are also a common to dominant component of the riparian woodland community along Brizziolari Creek.

Coastal live oak woodlands are common on the north facing slopes and canyons in Poly Canyon (as shown on previous photographs on the home page).  While coast live oak woodlands are variable, they are often completely dominated by a dense cover of tall coast live oaks; many of which are multiple stemmed.  These oaks form a closed-canopied woodland composed of very old trees that typically vary from about 1 to 3 feet in trunk diameter; however, there are some smaller and larger trees present.  Several very large sprawling trees with large branches that come to the ground occur in some areas on campus.

Oak woodland vegetation is important for animal cover, providing vertical and horizontal structure, nesting sites for birds, and shelter for numerous mammals.  The woodland also supports numerous insects and small mammals that are important food sources for other vertebrates in the area.  Snags provide excellent roosts for raptors, provide nesting cavities for owls, kestrels, woodpeckers, nuthatches, wrens, chickadees, and bluebirds.  Fallen logs become homes for abundant invertebrates that are important food sources for numerous vertebrate species including mice, lizards, snakes, and birds.  Environmental conditions are moderated by the woodland vegetation, reducing wind and temperature variation compared to grassland and coastal scrub communities.

The overstory of the coast live oak woodland in Poly Canyon is mostly composed of a dark, evergreen canopy of mature coast live oak trees.  The understory is quite variable from place to place depending on the microhabitat conditions.  In some places the understory may be composed of a relatively lush growth of ferns, shrubs, and shade tolerate herbs.  In other places, the understory is sparse consisting of a thick layer of litter with scattered shrubs and herbs.

Dominant Tree Species of the Coast Live Oak Woodland:

 Quercus agrifolia (coast live oak)

Common Associate Species found in Poly Canyon
Heteromeles arbutifolia (toyon)
Umbellularia californica (bay laural)

Coast Live Oak Woodland Community Common Understory Species found in Poly Canyon

Artemisia californica (California sagebrush)
Mimulus aurantiacus (sticky monkeyflower)
Pentagrama triangularis (goldback fern)
Pteridium aquilinum (bracken fern)
Rhamnus californica (coffeeberry)
Rubus ursinus (black berry)
Salvia spathacia (hummingbird sage)
Sambucus mexicana (elderberry)
Stachys bullata (hedge-nettle)
Symphoricarpos mollis (snowberry)
Toxicodendron diversilobum (poison oak)