Oregon white oak (Quercus garryana): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Quercus garryana Douglas ex Hook. in USDA PLANTS, beech family
Other names	Garry oak in British Columbia; white oak, post oak, Oregon oak, Brewer oak and shin oak elsewhere (Silvics)
Native status, USDA PLANTS	Native in Canada and the lower 48 states
Size, Silvics	Mature trees under favorable conditions are 15 to 27 m (50 to 90 ft) tall and 60 to 100 cm (24 to 40 in) in diameter; the handbook gives a record of 36.6 m (120 ft) tall, a crown spread of 38.4 m (126 ft) and a diameter of 246 cm (97 in)
Form, Silvics	Open-grown trees have short boles with very large, crooked branches forming dense, rounded crowns; forest-grown trees 70 to 90 years old have slim, straight boles and narrow crowns
Roots, Silvics	A deep taproot and a well-developed lateral system, very windfirm even in wet areas
Green weight of the wood, NRS-38	63 lb per cubic foot, without bark

Native range

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) says Oregon white oak has the longest north-south distribution of the western oaks, from Vancouver Island, British Columbia, to southern California, and is the only native oak in British Columbia and Washington and the principal one in Oregon. The range spans more than 15 degrees of latitude, from just below the 50th parallel on Vancouver Island south nearly to latitude 34 degrees north in Los Angeles County.

In British Columbia it is common in the eastern and southernmost parts of Vancouver Island and on adjacent smaller islands, from near sea level up to 200 m (660 ft) or more, and is not found on the mainland except for two separate stands in the Fraser River Valley. In Washington it is abundant on islands in Puget Sound and from there south and east to the Columbia River at elevations up to 1160 m (3,800 ft). It is widespread at lower elevations in the Willamette, Umpqua and Rogue River valleys of western Oregon, and common in the Klamath Mountains and on inland slopes of the northern Coast Ranges in California to San Francisco Bay. In small tree and shrub sizes it extends inland to just east of the Cascade Range and south along the western Sierra Nevada.

Flowers

Silvics says the species is monoecious and flowers somewhat later in spring than many of its associates, with flowering noted in March, April, May and June, concurrent with new leaves and twig growth. Male catkins are pale yellow tinged with green and in one collection ranged from 3 to 10 cm (1.2 to 3.9 in) long.

Stands and inventory

The handbook says inventories show the Oregon white oak type on at least 361,400 hectares (893,000 acres) in California, Oregon and Washington, and that the species makes up 26.2 million cubic m (926 million cubic feet) or more of growing stock. It describes open-grown trees as occupying much space but producing little commercial volume except for fuel. It also notes that large trees have withstood annual or periodic fires for years while small oaks may be killed or badly damaged, and ties the increased density and spread of oak stands to the arrival of fire control.

Landscape and food uses

Silvics says the species is not grown commercially for landscape purposes, but scattered native trees, groves and open stands are highly valued scenic assets in wildland, farm, park and urban areas. It records that mistletoe collected from the trees is sold as a decorative minor product, that meal or mush made from acorns of many oaks including this one was a common food of Native peoples, and that livestock prefer white oak acorns to those of black oaks.

Wood

Silvics says the wood is dense, with an oven-dry specific gravity from 0.52 to 0.88, moderate strength in static bending, high compression and shear strength, and outstanding side hardness among 20 northwestern woods, though it does not absorb shocks well. It says the heartwood is at least as durable as that of white oak, and that specialty items, fence posts and fuel are the primary uses, with the wood considered one of the best fuels for home heating. Older uses it lists include flooring, interior finish, furniture, cooperage staves, cabinet stock, baskets, handle stock, felling wedges and ship construction. The Wood Handbook (FPL-GTR-282, 2021) lists Oregon white oak among the western hardwoods in Table 2-1 but has no separate Oregon white oak row in Table 5-3b, so no strength figures are given here.

The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Diseases, insects and damage the handbook names

Silvics (1990) says more than 110 pathogens have been found on the leaves, twigs, trunk or roots of Oregon white oak, that most are of minor consequence and many are saprophytes, and that although the tree hosts hundreds of insect species, damage is usually not severe and loss of trees to insects is uncommon.

Foliage fungi. Leaf spot, mildew and anthracnose fungi sometimes attack the foliage. The handbook describes an anthracnose (Gnomonia quercina) that in 1968 caused moderate to severe dying of leaves and possibly death of oak trees in southern Pierce County, Washington.
Hairy mistletoe. Common on Oregon white oak in Oregon and California, forming conspicuous rounded growths in the upper crown; the handbook says its effect on growth and vigor is undetermined. See mistletoe on trees.
Rots. White pocket root and butt rot (Polyporus dryophilus) and shoestring root rot (Armillaria mellea) are named as probably the most damaging.
Defoliators. The western oak looper is named as probably the most damaging insect from Oregon north to British Columbia, defoliating oaks over large areas of the Willamette Valley in some years, with the damage described as temporary. The western tent caterpillar, the Pacific tent caterpillar and leafrollers are also listed.
Gall wasps. Several species form galls on twigs, branches and leaves; one kind forms seedlike galls under the bark of branches that the handbook says often girdle and kill the branch.
Acorn insects. Larvae of the filbertworm and the filbert weevil damage acorn crops before the acorns ripen.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.