Quercus garryana is an oak tree species named for Nicholas Garry, deputy governor of the Hudson's Bay Company.

The species is found in the Pacific Northwest, with a range stretching from southern California to southwestern British Columbia.

The leaves are deciduous, 2–6 in (5.1–15 cm) long and 1–3 in broad, with 3–7 deep lobes on each side, darker green on top and finely haired below.

Other individuals may have subtle mixtures of brown, green and yellow, or in less common cases a fairly bright 'peas and corn' effect.

[8] The northernmost population of Garry oak can be found just below 50°N on Savary Island, in the northern stretches of the Strait of Georgia.

In these areas, oak woodlands are seral, or early-successional; they depend on disturbance to avoid being overtaken by Douglas-fir (Pseudotsuga menziesii).

In addition, early settlers' records, soil surveys, and tribal histories indicate that deliberate burning was widely practiced by the indigenous people of these areas.

Fire perpetuated the grasslands that produced food sources such as camas, chocolate lily, bracken fern, and oak; and that provided grazing and easy hunting for deer and elk.

Such fires prevented Douglas-fir and most other conifer seedlings from becoming established, allowing bunch grass prairie and oak woodland to persist.

Parks Canada states that Garry oak woodlands support more species of plants than any other terrestrial ecosystem in British Columbia.

[15][16] The Donation Land Claim Act of 1850 encouraged settlement of Washington and Oregon by the United States and marked the beginning of the end of regular burning by native peoples of the area.

[15]: Perdue  The arrival of Europeans also reduced the number of natural fires that took place in Oregon white oak habitat.

[19] Remaining Oregon white oak woodlands are threatened by urbanization, conversion to Douglas-fir woodland, and invasion by shrubs, both native and nonnative (Scotch broom Cytisus scoparius, sweetbriar rose Rosa eglanteria, snowberry Symphoricarpos albus, Indian plum Oemleria cerasiformis, poison-oak Toxicodendron diversilobum, English holly Ilex aquifolium, bird cherry Prunus avens).

[5][29] The bitterness of the toxic tannic acid would likely prevent anyone from eating enough to become ill.[29] Native Americans ate the acorns raw and roasted, also using them to make a kind of flour.

[30] Although it was popularly used around the turn of the 20th century,[4] historically, the tree has not been regarded as having significant commercial value and is frequently destroyed as land is cleared for development.

[33] When used as firewood, Oregon white oak produces 28 million British thermal units per cord (2.3 MWh/m3) burned.