The blackjack oak, Quercus marilandica, is a tree in the red oak grouping of oaks. It was first described and named in 1704 in the colony of Maryland. The scientific name created for it in latin means “from Maryland”. The common name of the blackjack oak could not only be a reference to the tree’s almost black bark, but to the tree’s tough features that allow it to “beat out” other trees in survival. The blackjack is known as the symbol on the flag of pirates. It is also the short, leather-covered club that was once commonly used by peace officers and night watchmen. There can be much significance in a tree’s name.
An interesting encounter with this tree by early settlers helps illustrate how tough this oak was. The Cross Timbers region of Texas and Oklahoma is a transition zone from humid eastern woodland forests to drier western prairie grassland. In this region and in this period, frequent prairie fires encouraged the formation of an almost impenetrable barrier of dense undergrowth, with scrubby but occasionally large blackjack oaks and post oaks. These oaks were seldom more than 40 feet tall, but could be found 50 to 60 feet tall. Washington Irving described his 1835 passage through this area in his A Tour on the Prairies as “…like struggling through forests of cast iron.” The tough nature of this native tree has helped it grow 
where other trees can’t.
Blackjack oaks have been documented to live as long as 230 years. Slow- to medium-growing, they grow best in sunny locations. They like well-drained, acidic sites with rich soil. However, they adapt readily and grow most commonly in poor conditions with dry, acidic, sandy or rocky soil. Tolerant of fires, if top-killed they sprout vigorously from root sprouts. Trees from these root sprouts can make viable acorns in as little as 4 years. Perhaps the blackjack oak’s greatest threat to survival is man, as these trees are often replaced with faster growing trees that are considered more useful.
The champion blackjack oak in Atlanta is listed as measuring 67.5 feet in height, 75 inches in circumference, and 57 feet in spread. There are several near my neighborhood and one is perhaps 40 feet tall. This oak’s short, stout and often contorted branches form a narrow, compact, round-topped or open head. Twigs are stout, stiff, and grayish-brown. They are hairy at first but become smooth later. Buds are also hairy and reddish-brown, narrowly cone-shaped and pointed. The bark is almost black, and deeply divided into small square or rectangular plates that feel rough.
Leaves on the blackjack oak measure 4 to 8 inches long 
and wide, and are widest toward the tip. All varieties of blackjack oak have leaves that are simple, leathery, and have 3 (rarely 5) broad lobes that are very shallowly incised. The lobes have bristle tips where veins end at the edge, but the bristles may wear off. The upper leaf surface is dark- or yellowish-green and shiny, and the lower surface is pale yellow-brown or yellow-green, with brown hairs along the veins. Petioles are attached alternately on twigs, and may be ¼ to 1 ½ inches long. They are medium thick, stiff, and pubescent with tiny brown hairs. Foliage in autumn is yellow-brown with splashes of red, and persists through winter.
Male and female catkins found on the blackjack oak are yellow-green and 4 to 5 inches long. Pollination occurs in April and May by the wind. Acorns produced are about ¾ inches long, ovoid, and have a stout point at the tip. They are light yellow-brown, faintly striated, and have a thick, red-brown cap that covers 1/3 to 2/3 of it. The cap has loose, hairy scales and no fringe cover. Acorns mature in September-October of the second year, typical of oaks in the red oak family.
The blackjack grows slowly, and is considered scrubby and unattractive for use as a specimen or ornamental. It is usually considered too small to mill for lumber. Due to the wood’s twisted grain, it is difficult to split. 
However, it produces a hot flame and hot coals, and is considered excellent to use in wood burning stoves, for smoking meat, and in making charcoal. The wood spits when burning, and is not recommended for fireplaces. This is because the wood’s vessels are blocked by tyloses, unusual for wood in the red oak group. This characteristic also makes the wood resistant to rot when in contact with the ground, and because the wood is also hard, heavy, strong and brittle, it is excellent for use as fence posts. Native Americans reportedly used the bark to treat dysentery. Acorns are an important food for deer, birds, and other animals.
Though the blackjack oak has little commercial value, it deserves credit for its ability to grow in places where few other trees can compete. It has a respectable history doing this, and it helps sustain important eco systems. The tree’s native range is through the southeastern and central United States, from Long Island in New York to Florida, and westward to east Texas and Oklahoma. As this tree and similar ones are replaced with faster-growing and more commercially useful trees, the profits earned will be our loss.
