Black Oak (Quercus velutina)

Description: This tree is typically 60-80' tall at maturity, consisting of a single trunk about 1½-3' across and a pyramidal or ovoid crown with ascending to widely spreading branches. The crown is somewhat open and irregular and the branches are often crooked. Trunk bark is blackish gray or brownish gray; it is shallowly to moderately furrowed, rough-textured, and often dividing into irregular rectangular plates. Branch bark is more gray and smooth, while the rather stout twigs are gray to brown with white lenticels. The terminal buds of twigs are pubescent and either tan or gray. Alternate leaves occur along the twigs. Individual leaves are 3-9" long and 2½-6" across; they are ovate to obovate in outline and pinnatifid, dividing into 5-7 (less often 9) major lobes and some smaller secondary lobes. The lobes are pointed and they have short bristles at their tips; the sinuses between the lobes are concave. Leaves exposed to sunlight tend to have deeper lobes than those growing in the shade. The upper leaf surface is dark green, hairless, and glossy, while the lower surface is pale to medium green and dull. In the typical variety of Black Oak, the lower surface of mature leaves is hairless, except for patches of tan or reddish brown downy hairs near the forks of the major veins. In a more southern variety (var. missouriensis) of Black Oak, mature leaves have a scurfy canescence across the entire lower surface. The petioles are 1-3" long, light green to yellow, and glabrous or canescent; they often bend from the weight of the leaves.

Black Oak is monoecious, producing male (staminate) and female (pistillate) flowers on the same tree. The inflorescence of male flowers consists of a cluster of drooping yellowish catkins about 4-6" long. The central stalks of the catkins are pubescent. The female inflorescence consists of a short spike of 1-4 reddish female flowers. Each female flower consists of an ovoid ovary with a conspicuous tripartite style; the ovary is surrounded by floral bracts (phyllaries) that are scaly and pubescent. The blooming period occurs from mid- to late spring. The flowers are wind-pollinated. The catkins of male flowers soon wither away, while fertile female flowers are replaced by acorns. These acorns require 2 years to fully develop; at maturity, they are ½-¾" long and ovoid-globoid in shape. Each acorn has a cup at its apex that extends downward to about 1/2 of its length; the relatively loose scales of the cup become smaller as they approach its lower rim. Along the lower rim of the cup, the scales form a short fringe. Each acorn contains a single large seed. The woody root system produces a deep taproot and lateral roots. This tree reproduces by reseeding itself. The deciduous leaves become dull red, yellow, or brown during the fall. Trunk Bark

Cultivation: The preference is full or partial sun and mesic to dry conditions. Black Oak adapts to many types of soil, including those that contain deep loam, clay, rocky material, or sand. This tree begins the production of acorns after 20 years, and its longevity is not uncommonly 150-200 years. An infestation of oak wilt disease can be fatal.

Range & Habitat: The typical variety of the native Black Oak is a common tree that is found in every county of Illinois (see Distribution Map). The other variety of Black Oak (var. missouriensis), is restricted to a few southern counties within the state, where it is uncommon. This tree is native to the state. Habitats include upland woodlands, rocky open woodlands, sandy woodlands, upland savannas and sandy savannas, stabilized sand dunes, thinly wooded bluffs and rocky ridges, sandstone and limestone glades, and woodland borders. Sometimes Black Oak is the dominant canopy tree in sandy woodlands, sandy savannas, and upland rocky areas. It is rarely cultivated as a landscape tree.

Faunal Associations: Like other Quercus spp. (oaks), Black Oak is beneficial to many kinds of wildlife. The foliage is eaten by the caterpillars of several butterflies: Calycopis cecrops (Red-Banded Hairstreak), Satyrium calanus falacer (Banded Hairstreak), Satyrium edwardsii (Edward's Hairstreak), Satyrium liparops strigosum (Striped Hairstreak), and Parrhasius m-album (White-M Hairstreak); the foliage is also eaten by the caterpillars of a skipper, Erynnis brizo (Sleepy Duskywing). The caterpillars of numerous moths are known to feed on oaks; the Moth Table lists some of these species. Another major group of insect feeders are the larvae of wood-boring beetles (Buprestidae, Cerambycidae, etc.); the Wood-Boring Beetle Table lists many of these species. Other insect feeders include leaf beetles (Babia quadriguttata, Bassareus croceipennis, Metachroma quercatum, Pachybrachis dilatatus), the larvae of some weevils (Attelabus bipustulatus & Homoeolatus analis), plant bugs (Ceratocapsus modestus, Plagiognathus guttulosus), the Oak Lace Bug (Corythucha arcuata), several aphids (Myzocallis spp., Tuberculatus punctatellus), several leafhoppers (Eratoneura marilandica, Eratoneura manus, Erythridula cornipes, & others), Platycotis vittata (Oak Treehopper) and other treehoppers (mainly Cyrtolobus spp. & Telamona spp.), the larvae of several gall wasps (Amphibolips confluenta, Callirhytis spp.), the larvae of Caliroa quercuscoccineae (Scarlet Oak Sawfly), Schistocera emarginata (Bird-Winged Grasshopper), and Diapheromera femoratum (Northern Walkingstick).

The acorns of oaks are an important food source for many vertebrate animals. The Bird Table lists several upland gamebirds and songbirds that feed on acorns; mammals that consume acorns include the Black Bear, Opossum, Raccoon, Southern Flying Squirrel, Fox Squirrel, Gray Squirrel, Red Squirrel, Eastern Chipmunk, White-Footed Mouse, and White-Tailed Deer. White-Tailed Deer also browse on the twigs and foliage, while the Cottontail Rabbit gnaws on the bark of saplings and foliage of seedlings. Many birds, tree squirrels, bats, and other wildlife find shelter within the cavities of oaks, and many birds favor oak trees as providers of nesting habitat and feeding sites (e.g., warblers & other insectivorous birds are attracted by the many insects that feed on oaks).

Photographic Location: A sandy area near Lake Michigan at Indiana Dunes State Park in NW Indiana.

Comments: Black Oak is a member of the "red oak group" that has leaves with pointed bristly lobes and acorns that require 2 years to mature. The shape of its leaves are more variable than most oaks. At one time, the yellow-orange inner bark was used heavily in the leather tanning industry and it also produced an important yellow dye. Like other oaks, the heavy wood of Black Oak is hard and strong, therefore it is used to make wooden furniture, floors, interior finishing, barrels, railroad ties, and other wooden products. Black Oak can be distinguished from other oaks by the patches of tan or reddish brown hair that occur near the forks of the veins on the lower sides of its leaves (for the typical variety), the relatively long and slightly fringed cups of its acorns, and its often yellowish petioles. A southern variety of Black Oak (var. missouriensis), is slightly different by having a scurfy pubescence on the lower side of its leaves.