Quercus kelloggii, the California black oak or Kellogg oak, is an oak in the red oak section (genus Quercus, section Lobatae, series Agrifoliae) native to western North America.
Description
thumb|left|upright|Leaf and bark
Quercus kelloggii grows from one to several vertical roots which penetrate to bedrock, with large, laterally spreading roots extending off from vertical ones. It also has a number of surface roots. It can reproduce vegetatively with new growth sprouting from the root crown after the tree is top-killed by wildfire, logging, frost, or other events. The species also grows in shrubby scrub-oak form on poor sites. In open areas, the crown is broad and rounded, with lower branches nearly touching the ground or forming a browse line. In closed stands, the crown is narrow and slender in young trees and irregularly broad in old trees. Trunks are usually free of branches on the lower in closed stands. The acorns are relatively large, from long It can be found at altitudes of up to , for example near Mount Shasta. and California black oak occupies more total area in California than any other hardwood species. Livestock also make heavy use of this species for food and cover.
thumb|Young California black oaks
Older trees affected by heart rot have cavities which provide den or nest sites Acorns are heavily used by livestock, mule deer, feral pigs, rodents, mountain quail, Steller's jays, and woodpeckers. Acorns constitute an average of 50% of the fall and winter diets of western gray squirrels and black-tailed deer during good mast years. Fawn survival rates increase or decrease with the size of the acorn crop.
It is a preferred foraging substrate for many birds. All of 68 bird species observed in oak woodlands of the Tehachapi Mountains of California used California black oak for part of their foraging activities. Acorn woodpecker, Bullock's oriole, and Nashville warbler show strong preferences for California black oak. The parasitic plant Pacific mistletoe (Phoradendron villosum), which commonly grows on this oak, produces berries that attract birds, as well.
Uses
Some California Native Americans prefer California black oak acorns over those of other species for making acorn meal. Historically, this acorn was a staple food for many Native American groups, who usually leached out the bitter tannin.