Trees of Iowa: An Interactive Key

Black oak
(Quercus velutina)

Leaves are alternate, simple, lobed.  Lobes have pointed tips.  Fruit is an acorn.

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Black oak is a member of the broad red oak group (red, black, blackjack, pin, northern pin and shingle). This group is characterized by having bristles or points on the leaf lobes and acorns which mature in two growing seasons and sprout in the spring after maturity. 

Hardiness: Varies with the species of oak tree, ranging from zone 3 to zone 9.

Growth Rate:
Slow to Moderate

Mature Shape:
Broad, rounded

50-80 feet

40-60 feet; varies with species

Site Requirements:
Best growth in moist, well-drained soils. Adaptable to adverse soil conditions.

Flowering Dates: April - May

Seed Dispersal Dates: September

Seed Bearing Age: 20 years; optimum production 40-75 years

Seed Bearing Frequency: Every 2-3 years

Seed Stratification: Prechill for 1-2 months at 34°F to 40°F
Black Oak FruitBlack Oak Leaves

Black oak leaves are alternate, simple, 5 to 9 inches long and have 5 to 7 irregular bristle tipped lobes. The lobes extend 2/3 to 7/8 of the way to the midrib of the leaf and have broad U-shaped or circular sinuses. The leaves are lustrous and dark green in color on the upper surface and paler or coppery below with more or less scurfy pubescence and prominent tufts in the axils of the leaf veins. Buds are 1/4 to 1/2 inch in length, sharp pointed, angled in cross section and have gray-woolly bud scales. Twigs are stout and red-brown in color. The bark is thick, nearly black in color and deeply furrowed with narrow scaly ridges; the inner bark is orange-yellow in color. The acorns are 1/2 to 3/4 inch in length, red-brown in color, and enclosed for 1/3 to 1/2 its length by the acorn cup. Red oak has shallower and more evenly lobed leaves, reddish inner bark, smaller buds and a larger acorn enclosed less than 1/4 of its length by the acorn cup. 

Black oak is native in the eastern and southern halves of Iowa. It is a very common upland tree, often growing on dry ridges and southern or western slopes. It also occurs on moist upland soils in association with basswood, red oak and sugar maple; in eastern Iowa it can be found on bottomlands or terraces which are sandy and very well drained. 

Black oak provides a problem often encountered in the identification of oaks according to "Forest and Shade Trees of Iowa" by Peter van der Linden and Donald Farrar. "Most trees in southern and east central Iowa are quite typical of the species, having large, strongly angled, densely hairy buds and acorn cups with loosely attached scales. However, some of the trees called 'black oak' along the edge of this species' range in northeast and north central Iowa have small, slightly angled buds that are incompletely hairy and acorn cups with tighter fitting scales. These may be geographical variants or hybrids between black and red or Hill's oak. 

Black oak is seldom used as an ornamental. As a large shade tree, it is less attractive than many of the other native oaks. 

The wood of black oak hard, heavy and strong. The wood is usually of less value than red oak because the trees are often more open grown and tend to develop more branches. It is used in furniture, flooring, pallets, boxes, railroad ties, and mine timbers.


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Black Oak Fruit Black Oak Leaves Black Oak Leaves