Blackjack Oak

Description:

A small to medium-sized oak, 30-50 ft, with bristle-lobed leaves that are shiny on top & rusty-yellow hairy beneath. The short, nearly black trunk divides into many dense, contorted limbs, bark dark, furrowed; dead branches persistent. Leaf blades wedge shaped (obdeltoid - obovate) with a narrow, rounded base and broadening toward the tip. Blades shallowly lobed with usually an apical and 2 lateral lobes bearing bristlelike extensions (awns) of the main vein. Foliage glossy dark green turns red in fall and persists into winter. Acorn elliptic, broadly rounded at the apex and base, up to 3/4 inch long when mature; cap covering 1/2 the nut. This oak sometimes grows in colonies. GROWTH FORM: small to medium sized tree usually between 15 - 45 feet (4.6 - 19.8 m), occasionally to 95 feet (28.9 m), with an open irregular spreading crown of crooked branches and some dead twigs, slow growing and short lived. BARK: thick rough bark, nearly black, with deep furrows, mature bark forming irregular or rectangular plates, orange inner bark. TWIGS and BUDS: light brown twigs, finely pubescent; narrowly ovoid pointed buds, reddish-brown pubescent scales, 5-angled in cross section. LEAVES: pubescent petiole 1⁄4 - 3⁄4 inch (6 - 19 mm) long; leaf broadly triangular and widest near tip, 2 3⁄4 - 8 inches (70 - 203 mm) long, 2 3⁄4 - 8 inches (70 - 203 mm) wide, leathery, base rounded, thickened blade with 3 - 5 broad lobes, with 1 - 3 bristle- tipped teeth, apex obtuse; glossy yellowish-green above, pale green with dense brown pubescence (scurfy) below, secondary veins raised on both surfaces.

Habitat:

This tree was growing in the higher section of the park.

Notes:

Blackjack Oak grows in the eastern third of the state on acid sands, sandy loams, and clays. It grows to more than 50 feet tall and has distinctive large, three-lobed leaves that are club-shaped. It inhabits similar sites as Post Oak, Q. stellata, and is often considered an indicator of sandy, barren soils. It is drought tolerant, has dark green leaves and pleasing brown fall color, but it is very slow growing and intolerant of poorly draining or compacted soils. West of where the typical Blackjack Oak is found is a more xeric version that grows on sand or gravelly clay that is only slightly acidic.