Blackjack Oak

Blackjack_Oak_jpgMore than 200 species of oaks grow in the world, 60 of these occurring in the USA.  In general, the oaks are divided into two main groups: the red oaks and the white oaks.   The red oaks have bristle-tipped leaves and acorns that take two years to mature. The white oaks have rounded lobes and acorns that mature in one season.  Blackjack Oak is a red oak. There are four different tracts of specialized upland forests in the Pine Barrens known as dwarf or “pygmy” forest in New Jersey.  These four tracts cover 15,000 acres in Ocean and Burlington Counties.  These forests support growth of unusually short, 4 to 10 feet high, forests of mature growth.  Blackjack Oak is one of the three dominant trees in this forest. Blackjack Oak is a pioneer tree that is quick to spread over burned or eroded soil. It grows well on these sites and has become an indicator of poor, dry soil.  It grows as a small tree, generally reaching 20-30 feet in height, but occasionally will grow overt fifty feet tall.  It is common on dry soils in the pine barrens, here found with scrub oak (Quercus ilicifolia), black oak (Quercus velutina) and post oak (Quercus stellata).    On the Pitch pine plains, blackjack oak is usually the only other tree-sized companion to pitch pine. The trunk of Blackjack Oak is short and apt to be crooked and so are the branches.  There is little timber harvested from this tree.


Scrub Oak, Jack Oak


Quercus marilandica






Woody Tree


6 to 30 feet


Acorns September to November, mature in 2 years


Southern New York to Florida and west to Texas ~ Northern New Jersey and throughout Coastal Plain, most abundant in Pine Barrens


Late April to Mid May


Leaves alternate, simple, broadly obovate, very variable, 4-8 inches long, often as broad at three-lobed apex, lobes bristle tipped, dark green above, brownish below, turn yellow-brown in autumn ~ Twigs stout, red-brown wooly when young, become smooth and brown to ash-gray, buds harp, hairy ~ Flowers: male in 4-5 inch red-tinged catkins, female in short-stalked rusty spikes ~ Fruit oblong acorn, rounded at end, ¾ to 1 inch long, light yellow brown, half enclosed by light brown cup ~ Bark rough, deeply divided into nearly square plates 1-3 inches long, covered by small dark brown to black scales