Oak Trees are the dominant plants in the central oak woodland plant community that forms one of the main native ecosystems in West Sacramento.

Our native oaks can be classified into three subgenera of the genus Quercus: white oaks, red oaks, and golden oaks. White oaks have short styles and usually rounded, smooth leaf lobes. Their acorns mature in 6 months and taste sweet or slightly bitter. The insides of the acorn shells are hairless. They are immune to the sudden oak death pathogen. Red oaks have long styles and usually sharp leaf lobes, with spiny bristles at the tips of the lobes. Their acorns mature in 18 months and taste very bitter. The insides of the acorn shells appear woolly. The actual nut is encased in a thin, clinging, papery skin. Golden oaks closely resemble red oaks, except that golden oaks have short styles.

Because oaks are such a dominant tree in our native ecosystems, many of our native birds have evolved to depend primarily on oaks for food and shelter. Planting oak trees in your yard is an excellent way to attract rufous-crowned sparrows, oak titmice, lesser goldfinches, acorn woodpeckers, yellow-billed magpies, Nuttall's woodpeckers, white-breasted nuthatches, and Bewick's wrens.

Oaks are also the larval host plants for the California sister, Propertius duskywing, mournful duskywing, golden hairstreak, and gold-hunter's hairstreak butterflies.

Oaks Native to West Sacramento

Four oak species are native to West Sacramento.

Valley Oak (Quercus lobata). Photo by queerbychoice.Valley Oak (Quercus lobata) is a deciduous white oak tree that is native to all of West Sacramento. It can live to be over 500 years old and can grow fairly quickly to over 100 feet tall and about half as wide. It prefers full sun. It usually grows in dry areas but is more tolerant of water than any other California native oak; it can occasionally grow in wetlands (or in an irrigated lawn). It adapts to the conditions it finds itself in, so it can survive in a lawn if planted into a pre-existing lawn, but it will not survive if you suddenly plant a lawn under it after it's grown up in drier conditions.

The small, shallowly lobed leaves of Blue Oak (Quercus douglasii). Photo by queerbychoice.Blue Oak (Quercus douglasii) is a deciduous white oak tree that is native to all of West Sacramento. Highly drought tolerant, it invests much of its energy into root growth so as to find water in dry soil. It is therefore unusually slow growing above ground, increasing in height by no more than about a foot or so per year even under the best of conditions. It can live to be over 500 years old but never exceeds 100 feet in height. Its leaves have a bluish tint that helps reflect the heat of the sun rather than absorbing it; the leaves become bluer when the tree is more drought stressed. The leaves are usually 2–4 inches long and often have lobed edges. The acorns are usually about 1 inch long. The tree prefers full sun or partial shade.

Interior Live Oak (Quercus wislizeni) can be recognized by its tendency to have some holly-shaped leaves and some smooth-edged leaves—often with both leaf shapes on a single branch. Photo by queerbychoice.Interior Live Oak (Quercus wislizeni) is an evergreen red oak tree or large shrub that is native to all of West Sacramento. Highly variable in size, it can grow more than 70 feet tall but often stays under 30 feet tall and can even remain more shrublike than treelike. It tends to grow about equally as wide as it is tall. Its dark, leathery leaves are often but not always spiny-toothed, like holly leaves; trees at higher elevations tend to have a larger percentage of holly-like leaves, while trees at lower elevations have primarily fairly smooth leaves. Its acorns are long, narrow, and sharply pointed. It prefers full sun or partial shade.

Coast Live Oak (Quercus agrifolia) is an evergreen red oak tree that is native to the portion of West Sacramento that is south of the Sacramento Deep Water Ship Channel. It can live to be over 250 years old and grows to over 80 feet tall and nearly half as wide, though it is often shrub-shaped when young. It prefers partial shade.

Oaks Native to Other Parts of Yolo County

Six other oak species, plus one widely recognized naturally occurring hybrid, are native to other parts of Yolo County. In addition to the named hybrids, many other oaks in the wild are hybridized to some extent. They usually hybridize within the same taxonomic group (white oaks with other white oaks, red oaks with other red oaks).

White Oaks

Inland Scrub Oak (Quercus berberidifolia) is an evergreen white oak tree that is native to the Yolo County foothills, including the Capay Hills. It can grow to about 20 feet tall and 15 feet wide if sheltered by nearby trees or structures but stays smaller when more exposed to sun and wind. It prefers full sun or partial shade.

Coastal Sage Scrub Oak (Quercus dumosa) is an evergreen white oak shrub that is native to the Yolo County foothills, including the Capay Hills. It grows very slowly, to about 10 feet tall and equally wide. It prefers full sun.

Leather Oak (Quercus durata) is an evergreen white oak shrub that is native to the Yolo County foothills, including the Capay Hills. It grows slowly, to only about 12 to 15 feet tall. It prefers full sun. Often used as a street tree, it can tolerate garden soil but prefers dry soils with low fertility. In the wild, it is often associated with serpentine soil.

Oregon Oak (Quercus garryana) is a deciduous white oak tree that is native to the Yolo County foothills, including the Capay Hills. It can grow to as much as 90 feet tall and 30 feet wide in the Pacific Northwest but rarely exceeds 30 feet tall in Yolo County. It prefers full sun or partial shade.

Golden Oaks

Canyon Live Oak (Quercus chrysolepis). Photo by queerbychoice.Gold Cup Live Oak (Quercus chrysolepis) is an evergreen golden oak tree that is native to Davis and to the Yolo County foothills, including the Capay Hills. It can grow to over 100 feet tall and nearly 100 feet wide. Its 1- to 3-inch leaves are flat-shaped, spiny-edged, and rounder at the base but pointier at the tip. They are a glossy dark green on the upper surface but a dull golden on the underside. Its acorns are 1 to 2 inches long. The tree can grow in full sun, partial shade, or full shade.

Red Oaks

California Black Oak (Quercus kelloggii) can be identified by the bristles on the tips of its large, deeply lobed leaves. Photo by queerbychoice.California Black Oak (Quercus kelloggii) is a deciduous red oak tree that is native to the Yolo County foothills, only along the far western edge of the county. It can live to be over 500 years old and grows to over 100 feet tall and over 30 feet wide. It can grow in full sun, partial shade, or full shade.

Oracle Oak (Quercus × morehus) is a hybrid of Interior Live Oak (Quercus wislizeni) and California Black Oak (Quercus kelloggii). The former parent is evergreen and native to West Sacramento as well as to nearly all of Yolo County; the latter parent is deciduous and native to only the far western edges of Yolo County. Oracle Oaks are therefore semi-deciduous and found in the Yolo County foothills. They tend to stay shorter than California Black Oaks and can get a bit taller than Interior Live Oaks.