Chestnut oak

Appearance

The chestnut oak is readily identified by its massively-ridged dark gray-brown bark, the thickest of any eastern North American oak. The leaves are 12–20 cm long and 6–10 cm broad, shallowly lobed with 10–15 rounded lobes on each margin; they are virtually identical to the leaves of swamp chestnut oak and chinkapin oak, but the trees can readily be distinguished by the bark, that of the chinkapin oak being a light ash-gray and somewhat peeling like that of the white oak and that of swamp chestnut oak being paler ash-gray and scaly. The chinkapin oak also has much smaller acorns than the chestnut oak. The chestnut oak is easily distinguished from the swamp white oak because that tree has whitened undersides on the leaves. Another important distinction between the chestnut oak and the swamp chestnut oak is by the habitat; if it grows on a ridge, it is chestnut oak, and if it grows in wet bottomlands, it is probably the more massive swamp chestnut oak; however, this is not fully reliable.

Characteristics of the chestnut oak include:
⤷  Bark: Dark, fissured into broad ridges, scaly. Branchlets stout, at first bronze green, later they become reddish brown, finally dark gray or brown. Heavily charged with tannic acid.
⤷  Wood: Dark brown, sapwood lighter; heavy, hard, strong, tough, close-grained, durable in contact with the soil. Used for fencing, fuel, and railway ties. Sp. gr., 0.7499; weight of cu. ft., 46.73 lbs.
⤷  Winter buds: Light chestnut brown, ovate, acute, one-fourth to one-half of an inch long.
⤷  Leaves: Alternate, 5 to 9 in long, 3 to 4 1⁄2 in wide, obovate to oblong-lanceolate, wedge-shaped or rounded at base, coarsely crenately toothed, teeth rounded or acute, apex rounded or acute. They come out of the bud convolute, yellow green or bronze, shining above, very pubescent below. When full grown are thick, firm, dark yellow green, somewhat shining above, pale green and pubescent below; midribs stout, yellow, primary veins conspicuous. In autumn they turn a dull yellow soon changing to a yellow brown. Petioles stout or slender, short. Stipules linear to lanceolate, caducous.
⤷  Flowers: May, when leaves are one-third grown. Staminate flowers are borne in hairy catkins two to three inches long; calyx pale yellow, hairy, deeply seven to nine-lobed; stamens 7 to 9; anthers bright yellow. Pistillate flowers in short spikes; peduncles green, stout, hairy; involucral scales hairy; stigmas short, bright red.
⤷  Acorns: Annual, singly or in pairs; nut oval, rounded or acute at apex, bright chestnut brown, shining, one and a quarter to one and one-half inches in length; cup, cup-shaped or turbinate, usually enclosing one-half or one-third of the nut, thin, light brown and downy within, reddish brown and rough outside, tuberculate near the base. Scales small, much crowded toward the rim sometimes making a fringe. Kernel white, sweetish.

The acorns of the chestnut oak are 1.5–3 cm long and 1–2 cm broad, among the largest of Native American oaks, surpassed in size only by the bur oak and possibly swamp chestnut oak.

Habitat

This species is a predominant ridge-top tree in eastern North American hardwood forests. It often grows with multiple trunks, often as a result of logging or prior injury to the main stem. It is a long-lived tree, with high-quality timber when well-formed. The acorns of the chestnut oak are a valuable wildlife food.

Uses

Chestnut oak trees are generally not the best timber trees because they are usually branched low and not very straight, but when they grow in better conditions, they are valuable for timber, which is marketed as 'mixed white oak'.