Calflora, a 501c3 non-profit
Distribution by County   6990    
Quercus douglasii  Hook. & Arn.
Blue oak
Quercus douglasii is a tree that is native to California, and endemic (limited) to California.
Record Count by County

Alameda: 90 Kings: 44 Placer: 94 Stanislaus: 64
Amador: 56 Lake: 48 Sacramento: 150 Sutter: 28
Butte: 250 Los Angeles: 44 San Benito: 1119 Tehama: 346
Calaveras: 119 Madera: 146 San Joaquin: 27 Trinity: 11
Colusa: 41 Marin: 39 San Luis Obispo: 471 Tulare: 324
Contra Costa: 165 Mariposa: 123 San Mateo: 52 Tuolumne: 224
Del Norte: 1 Mendocino: 40 Santa Barbara: 137 Ventura: 9
El Dorado: 102 Merced: 60 Santa Clara: 121 Yolo: 11
Fresno: 1271 Monterey: 425 Shasta: 120 Yuba: 147
Glenn: 13 Napa: 127 Solano: 31
Kern: 478 Nevada: 81 Sonoma: 78

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals, including the Consortium of California Herbaria. [web application]. 2026. The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 06/13/2026).