Additional Resources

National Register Big Trees

Ohio State Plant Facts

What Tree Is It?

America's forestry movement actually started in Ohio with the creation of the American Forestry Association in Cincinnati in 1875.

Division of Forestry
2045 Morse Rd.
Building H1.
Columbus, OH 43229

A deciduous tree from the Beech Family (Fagaceae)

Black Oak, present throughout the entire eastern half of the United States (except for Florida), is present throughout almost all of Ohio (being scarce in some northwestern counties), but is most frequently found in the foothills west of Appalachia and the sandy ridges near Lake Erie. It is a deeply taprooted Oak of dry soils, often in conjunction with Scarlet and Chestnut Oaks in southeastern Ohio. It is also frequently confused with the more mesic Red Oak, as their idenfication traits are much more similar than different.

Black Oak may reach 60 feet tall by 60 feet wide when found in the open, but its shape is among the more variable of the Oaks, being taller or more dwarfed, depending upon the site where it is located. The Red Oak group is sometimes alternatively known as the Black Oak group, in reference to this Oak, which has dark gray to black bark with age. As a member of the Red Oak group and the Beech Family, it is related to the Beeches, Chestnuts, and other Oaks.

Planting Requirements- Black Oak prefers soils that are moist, rich, deep, well-drained, and acidic. Ironically, it is often found in extremely dry sites with average to poor soils, where it can successfully compete with its tough environment. It adapts to soils that are neutral or slightly alkaline in pH. It thrives in full sun to partial sun, and is found in zones 3 to 9.

Potential Problems - Other than cosmetic blemishes on its foliage due to minor insect feeding, Black Oak is basically problem-free, although it may on occasion be subject to the standard army of pests and pathogens that afflict the Oaks.

Leaf Identification Features

Leaves of Black Oak are alternate, moderately shiny, broadly obovate, with five to nine lobes that have bristles terminating each tooth on the forward-pointing lobes. Sinuses vary from tree to tree in terms of their depth, with some shallow, others two-thirds of the way to the midrib.

Petioles that are green in spring and early summer often turn to yellow or scarlet by late summer, when buds have almost fully formed for the following year. Black Oak often has good late fall color, ranging from yellow to brick red.

Other Identification Features

Black Oak is monoecious, with its golden male catkins fertilizing the rarely noticed miniature female flowers in mid-spring. As a member of the Red Oak group (sometimes called the Black Oak group, in reference to this tree which closely resembles Red Oak), the fruits take two years to develop into mature acorns. As such, the first year immature fruits are not obvious (except to the keen observer looking for them) until the second year (upper right), when they fill out rapidly and ripen in late summer and early autumn.

Twigs of all Oaks terminate in a cluster of buds, and those of Black Oak are slightly above average size as compared to other Oaks, being light-colored on reddish-brown twigs.

The mature bark of Black Oak is dark gray to near black, moderately to deeply ridged and furrowed , supposedly with an inner bark that is subtilely yellow or orange.