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Oaks (Quercus)

  • Fruit is an acorn.
  • Leaves are simple and alternate. They are most commonly lobed and deciduous, but may be unlobed and persistent.
  • Twigs have star-shaped piths.
  • Buds are large and clustered at the tips of their twigs.



As the lion symbolizes courage, so the oak stands for strength, inspiring the Roman poet, Virgil, to write nearly 2,000 years ago: "Full in the midst of his own strength he stands, stretching his brawny arms and leafy hands."

Oaks comprise one of the largest and most diverse groups of broadleaved trees in the world - with approximately 500 species worldwide and 60 species in North America. Oaks come in all shapes and sizes. Some have huge, wide-spreading crowns while others are small shrubs; some are evergreen while others are deciduous; some grow on very wet sites while others tolerate drought; some have lobed leaves while others are unlobed. Perhaps the three things that all oaks share are acorns, star-shaped piths (the inner core of the twig), and clusters of large buds at the tip of their twigs.

Fortunately for those of us trying to identify them, only 3 Oregon oaks each tree size, but many more are planted in lawns and parks throughout the state. Three additional natives grow only as shrubs, but they are merely varieties of the other species and will not be described here.


California black oak: leaves have pointed lobes; acorns have deep caps.

Oregon white oak: leaves have rounded lobes; acorns have shallow caps.

canyon live oak: small evergreen leaves may have either smooth or spiked edges; acorns have variable caps.


For more information on the ashes native to the Pacific Northwest, go to the species page or see "Trees to Know in Oregon".


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