956 Quercus albaCommon Names: white oak Family: Fagaceae (beech Family)
The handsome white oak is among the grandest and most important of North American trees. Named for its gray-white bark, the white oak is easily recognized and is a favorite of everyone. White oaks can get up to 150 ft (45.7 m) tall with trunks 6-8 ft (1.8-2.4 m) in diameter, but are more commonly 60-80 ft (18-24 m) tall with 2-3 ft (0.6-0.9 m) trunks. In the forest, white oak grows straight and tall with a narrow crown, but specimens grown in the open develop a broad, wide spreading, rounded crown. The distinctive ashy gray bark is broken into scaly plates separated by vertical fissures. The bark can be as much as 2 in (5 cm) thick on large trees. The leaves too are distinctive: They are 5-9 in (13-23 cm) long with 7-9 rounded lobes - the quintessential oak leaf. They are pinkish as they unfold in spring, dark green in summer, and turn purplish red in fall. The acorns are about an inch long, with a bowl-like cup enclosing the lower one-forth of the shiny brown nut. Typical for members of the White Oak Group (see the northern red oak profile), the acorns are sweet and mature in a single season. Large seed crops, called masts, are produced every 4-6 years.
There are several named forms and hybrids with other species that have landscape potential.
White oak, Quercus alba, occurs naturally throughout eastern North America from southern Ontario and Quebec, south to eastern Texas and northern Florida, excluding the lower Mississippi Delta and a narrow band along the northern Gulf Coast. White oak does not grow in pure stands, but rather is a component of mixed hardwood forests, usually with other oaks, hickories, sweetgum, American basswood, yellow poplar and American beech. White oak grows on a variety of soil types, but does best on rich, well drained soils on slopes and bottomlands. It achieves its best growth in the Ohio River Valley and on western slopes of the Allegheny Mountains.
CultureWhite oak is a fairly fast growing tree on good sites with ample water. It does best in well drained soil that is slightly acidic. White oak can grow to 20 ft (6 m) tall in 10-15 years, but it probably will take 100 years to get 80 ft (24 m) tall. Light: Full sun Moisture: Water young trees until established. Hardiness: USDA Zones 4 - 9. Propagation: White oaks are normally propagated by seed. Acorns of white oak do not store well, so plant them as soon as they fall (preferably just before they fall to lessen the likelihood of insect damage). Remove the cups and check for seed viability by flotation in water: nuts that sink are sound; those that float should be discarded. White oak acorns have no dormancy, and will germinate almost as soon as they drop from the tree. Forms and hybrids may be grafted onto seedlings of the species.
The stately white oak makes a magnificent street tree. It bestows a special elegance to parks and large lawns. There is no finer shade tree for eastern North America. Fall color often persists for several weeks. Plant young trees 40 ft (12 m) apart, and expect to thin them to 80 ft (24 m) apart in 20 years or so.
The wood is strong, close grained and durable, and one of the most important woods harvested in North America. It is used for support timbers, railroad ties, flooring, furniture and cabinets. Before the availability of steel, ships were made from white oak wood. The sweet acorns (palatable even to humans) are relished by forest birds and mammals, so much so that few acorns survive to germinate. For human consumption, boil the acorns in water to remove the bitter tannins. Native Americans used the bark and inner bark for medicinal purposes. The acorns were either boiled in water or soaked in a lye solution to remove the tannins, then pounded and ground to make a flour that was made into mush or used to thicken soups. The lye water for leaching the acorns was made by soaking wood ashes in water.
The white oak probably is the largest of the oaks, a genus that includes more than 400 species in the New World, Europe and Asia. It is a handsome tree indeed, but probably too large and too slow growing for most landscape applications.
Steve Christman 7/29/02, 5/24/03, 9/22/03, 4/18/12