Understory trees typically grow in wooded areas or forests beneath the canopies of much taller trees, often hardwoods. In Ohio, many different types of native trees grow as understory trees. The most common understory tree species include the Ohio Buckeye, pawpaw, American hornbeam and serviceberry. Understory trees characteristically grow to only medium or small, shrub-like heights.
The official state tree of Ohio, the Ohio Buckeye (Aesculus glabra) is a deciduous tree that’s part of the horsechestnut family. In moist, well-draining, rich soils, the Ohio buckeye grows up to 60 feet tall with a 30-foot spread. The Ohio Buckeye is found growing as an understory tree mostly in the western part of the state in more alkaline soils. Growing in partial sun to shade, this understory tree has hand-shaped compound leaves arranged opposite each other in pairs along the stems. Ohio buckeye trees bloom with yellowish-green flowers in early spring that have long stamens, followed by individual or clustered, spiny, golden-brown husked fruits enclosing a nut.
The pawpaw tree (Asimina triloba) is a native understory tree found growing throughout Ohio, usually in moist locations such as creek banks and ravine bottoms. The pawpaw grows up to 25 feet tall and 15 feet wide with a dense, pyramidal canopy. Growing best in moist, deep, rich soils, the pawpaw tree has somewhat tropical-looking foliage with large, shiny, dark-green leaves that are widest toward the ends. The leaves hang down from the stems and turn yellow or golden-brown in autumn. Pawpaw trees bloom in purplish-red flowers in mid-spring that are small and attractive but inconspicuous. In late summer, the pawpaw produces individual or clustered oval fruits that turn from light green to yellowish-brown as they ripen. The fruits are considered a delicacy by some, with pulp that tastes similar to banana custard.
Also called the musclewood, ironwood or blue-beech, the American hornbeam (Carpinus caroliniana) is a native Ohio understory tree that grows 20 to 30 feet tall with a slender, 4- to 8-inch-diameter trunk. The hornbeam’s leaves are oval with pointed tips and toothed edges, growing 2 to 3 inches long. The leaves are arranged in an alternating fashion along the stems and the side veins run directly to the larger teeth on the leaf edges. These decidous trees have smooth, gray bark with some irregular ridges running lengthwise on the trunk. The bark is also sometimes banded with dark horizontal rings on the trunk. The American hornbeam produces catkin flowers, followed by nutlet fruits that are 1/3 of an inch long and fall with the leaflike female flowers still attached. The hornbeam tree grows best in low-lying areas, along streams and in forests.
Also called shadbushes or Juneberry trees, serviceberry trees (Amelanchier spp.) are found growing in the northern and eastern parts of Ohio, usually in moist, fertile forests as an understory tree. The serviceberry grows up to 25 feet tall and produces purplish-black or red berry-like, 1/3-inch-diameter fruits in June, preceded by white flowers in the spring. The leaves are 1-1/4 to 3-1/4 inches long with rounded bases and pointed tips, turning reddish-orange in autumn. The serviceberry’s leaves have finely-toothed edges and are alternately arranged along the stems. The serviceberry tree has thin, smooth, grayish bark on the branches and upper trunk, while the older bark develops shallow fissures. The trunk is short and the tree may have multiple trunks with a shrub-like form.