Marin County
University of California
Marin County

Oak Identification

True oaks are divided into three general categories, or “clades”.  Oaks frequently hybridize between species, making exact species identification a tad difficult in some situations.  Clades matter to us because oaks only hybridize within their own clade.  Furthermore, it turns out that some clades are susceptible to certain diseases, such as sudden oak death, while others are functionally immune.  Thus, even if you cannot put your finger on exactly which oak species you have, if you can put your oak into a given clade, you still have a lot of information to work with. 

We list here only oak trees that grow within the North Bay region.  There are several scrub oaks (oaks that do not commonly exceed 15 feet in height) that are common to the region as well.

Tanoaks are not true oaks, and therefore don’t fit within these classifications.  However, it is a closely related species (hence the early confusion, and the name Tanoak), and it is listed here for comparison purposes.

The Red Oaks (section Lobatae)

Quercus agrifolia: Coast Live Oak
Quercus agrifolia: Coast Live Oak
Quercus kelloggii: Black Oak
Quercus kelloggii: Black Oak
Quercus parvula: Shreve Oak
Quercus parvula: Shreve Oak
Quercus wislizeni: Interior Live Oak
Quercus wislizeni: Interior Live Oak

The White Oaks (section Quercus)

Quercus douglasii: Blue Oak
Quercus douglasii: Blue Oak
Quercus lobata: Valley Oak, Roble
Quercus lobata: Valley Oak, Roble
Quercus garryana: Oregon White Oak
Quercus garryana: Oregon White Oak

The Golden Oaks (section Protobalanus)

Quercus chrysolepis: Canyon Live Oak
Quercus chrysolepis: Canyon Live Oak
Quercus chrysolepis: Canyon Live Oak
Quercus chrysolepis: Canyon Live Oak
Quercus chrysolepis: Canyon Live Oak
Quercus chrysolepis: Canyon Live Oak

Tanoak 

Lithocarpus densiflorus: Tanoak
Lithocarpus densiflorus: Tanoak
Lithocarpus densiflorus: Tanoak
Lithocarpus densiflorus: Tanoak

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