California Black Oak
Quercus kelloggii
The Sierra and coastal-range black oak, a deciduous red-group oak with large, bristle-tipped leaves and acorns of great historic importance to California's Indigenous peoples. A keystone wildlife tree; like other Western oaks it resents summer irrigation over its roots and is pruned in the dry season.
Field reference
Family
Fagaceae
Growth rate
Moderate
Mature size
30–80 ft tall, 30–60 ft spread
Hardiness zone
7–9
Soil preference
Well-drained foothill and mountain soils; summer-dry once established
Sun
Full sun
Pruning window
Mid-summer (dry season) to reduce disease and borer activity
Wood properties
Heavy, hard red-group oak; the most important hardwood timber oak in California. Strong, spreading limbs that carry large loads — rig long laterals conservatively.
Native range
Mountains and foothills of California and southwest Oregon
Green weight
58 lb/ft³
Pests & diseases to watch
Spongy Moth (formerly Gypsy Moth)pest · High severity · peak Caterpillars feed and defoliate May–June; egg masses laid mid-summer overwinterPowdery Mildewfungus · Low severity · peak Late spring through fall, worst in humid, shaded, crowded conditionsArmillaria Root Rotfungus · High severity · peak Decline visible in summer drought stress; honey mushrooms appear in fall
Common questions
Should I water a California black oak in summer?
Avoid regular summer water near the trunk of established trees — like most California oaks it is adapted to dry summers and is prone to root and crown rots when irrigated. Keep lawns and sprinklers away from the root zone.
Why are California black oak acorns significant?
They were a dietary staple for many California tribes, valued for flavor and storage, and the species remains a cultural and ecological keystone. The large acorns also feed deer, bears, and woodpeckers.
Related species in Fagaceae
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