White oak is a popular and long-lived ornamental shade tree that grows 50 to 100 feet tall at a slow-to-medium rate. Adaptable to a variety of soil types, it prefers slightly acidic, moist, well-drained soils and is tolerant of moderate drought and occasional wet conditions; however, it’s not as tolerant of alkaline or disturbed urban soils, soil compaction, or very wet areas. When grown in the open, its stout trunk supports massive lower branches that stretch out laterally, displaying slightly blue-green leaves that change to shades of red, burgundy, and sometimes purple in the fall. Some leaves remain on the broad, rounded crown during winter. A distinguishing feature of white oak is that the bark tends to form overlapping scales halfway up the trunk. The common name may be derived from two features: newly cut wood is light beige to almost white, and the undersides of the leaves are a whitish shade of green.
Oak trees are considered a keystone plant because they provide so many ecological services. They host nearly 500 species of Lepidoptera larvae in central Ohio. The acorns, which produce mast crops every 4 to 10 years, are extremely important for wildlife. White oaks are less susceptible to oak wilt than the red oak species.
White oaks have an impressive lifespan of 300 to 500 years, which gives them time to gain celebrity status. Two such trees are the “Shawshank Tree” and the Bedford oak. The former is seen in the last few minutes of the movie, The Shawshank Redemption. The 200-year-old tree was a popular tourist attraction until it was split by lightning in 2011. The latter tree is a 500-year-old sprawling, gnarled giant in Bedford, NY. It has lived through Native American settlements to the Revolutionary War to current times.
Native habitats include mesic and dry woodlands, ridges, and valleys. The oaks become shrubbier in high altitudes. Plant them as ornamentals and shade trees, and give them room to spread their limbs.
Plant Characteristics:
Grows 50-100’ tall and wide in open areas.
Prefers full sun but tolerates part shade, especially when young.
Prefers slightly acidic-to-neutral, moist, well-drained soils of variable types. Alkaline soils may cause chlorosis.
Green or yellowish male catkins and reddish female flowers appear in spring, followed by stalkless, ½-1” oblong, light brown acorns with warty, scaly caps covering ¼ of the nut. The nuts ripen September-November.
Spring leaves emerge silvery pink and downy, growing 5-8” long with 7-9 rounded lobes and sinuses of variable shapes. The glossy green color changes to red, burgundy, or purple in autumn, depending on growing conditions.
Trunk is short and stocky when grown in the open and taller when grown in competitive forests. Bark is light or dark gray to whitish in color. The fissures are shallow and scaly.
Wildlife Value:
Native host for 477 species of Lepidoptera larvae, including the imperial, elm sphinx, and great leopard moths pictured here.
The acorns are eaten by birds, mammals, and rodents. Leaf buds are eaten by several bird species, and all parts of the tree are a favorite food for deer.
Medicinal, Edible, and Other Uses:
The acorns are rich in protein and fat. After leaching out the tannins, acorns are best roasted or boiled and dried. Then, they can be eaten as a nut, dipped in syrup to make candy, or ground into meal or flour.
White oak’s water- and rot-resistant qualities give it a history of illustrious uses. The USS Constitution (“Old Ironsides”) was made of white and other oak lumber, and the keels of mine sweepers and patrol boats in WWII were produced from white oak. The wood, often called “stave oak,” is also the preferred option for making wooden barrels for wine and whiskey because its microscopic tissues called tyloses “plug” the vascular cells of the wood, thus preventing the barrels from leaking. The wood also imparts flavor to the liquids. In fact, federal regulations state that bourbon whiskey must be aged in charred new oak, which is generally understood to mean American white oak.
The wood is used extensively in Japanese martial arts for weapons because of its resiliency, strength, and lower probability of splintering. It is also used to finish the interior of houses, to build ships and agricultural implements, and to make furniture.