Blackjack Oak

Family: 
Fagaceae (oaks)
Description: 

A small to medium-sized tree with a rounded, irregular crown; distinctive bark; and a tendency to retain dead branches on the middle to lower part of the trunk. It is well limbed along the entire length of the trunk.

Leaves distinctively wedge- or bell-shaped; alternate, simple, bristle-tipped, leathery and shallowly 3–lobed. Upper surface is dark green and shiny; lower surface is yellow-brown or yellow-green, with tan to brown hairs. Several leaves persist in winter.

Bark resembles alligator hide; blackish, very rough, with square or rectangular blocks.

Twigs stout, stiff, grayish-brown and densely hairy at first, smooth later; buds reddish-brown, narrowly cone-shaped, hairy.

Flowers April–May; in catkins.

Fruits September–October, a yellow-brown acorn, 1/2 to 1 inch long; cup deep, turban-shaped, red-brown, scales loose, hairy, covering 1/3 or 1/2 of the nut. Stalk very short. Acorns ripen in autumn of second year.

Size: 
Height: up to 60 feet, but rarely more than 30–40 feet.
Habitat and conservation: 
Occurs in acid soils over sandstone, chert or igneous bedrock, on dry, often level uplands, slopes and glades. Common in forests that have been badly burned; often found growing on the poorest soils. Blackjack oak can withstand fire because of its thick, insulating bark and its ability to resprout. It is one of the first trees to occupy an area following a fire. Relatively short-lived, the slow-growing species cannot grow in shade.
Distribution in Missouri: 
Statewide.
Human connections: 
The wood has been used for railroad ties, fenceposts, charcoal and fuel. Native Americans had many medicinal uses for oaks. Blackjack oak is a humble, unadmired tree, but we must also give credit to this rugged tree for living in places where few other trees will live.
Ecosystem connections: 
Jays, woodpeckers, turkey, mice, squirrels, raccoon and deer eat the acorns. Innumerable organisms, from lichens to spiders, birds, snakes, squirrels and raccoons, live in oak trees, in cracks in the bark, among the leaves, in the branches or in hollow wood.