THERE ARE TWO members of the birch family that often go unnoticed in the understory of our forests: the Eastern hop hornbeam (Ostrya virginiana) and American hornbeam (Carpinus caroliniana). Both of these hornbeams are slow-growing, diminutive trees that have hard and heavy wood. Both trees prefer shady conditions and grow best in deep, fertile, moist, well-drained soils. The American hornbeam and Eastern hop hornbeam both have male and female flowers on the same tree with the distinctive "catkin," which develops during the summer.
The Eastern hop hornbeam gets its scientific name Ostrya from a Greek word meaning "bone," since the wood of this tree is very hard and heavy. The hop part of the name is derived from the bladderlike seed pod that resembles cultivated "hops." Another common name of this plant is "ironwood," an accurate description of this hard, dense, rot-resistant wood. There are three species of ironwood found throughout North America and eight additional species found throughout Europe and eastern Asia.
The Eastern hop hornbeam is a small understory tree that rarely grows taller than 40 feet. The bark on young trees is a smooth brownish-red but changes to a uniform brown color with a shaggy appearance. Ironwoods generally have a single trunk and an irregular crown. They prefer the shade but can also grow in the open areas.
Ironwood has been used as an ornamental but its slow growth, intolerance to salt and poor ability to transplant has limited its desirability for landscape plantings. The leaves, catkins and nuts are readily eaten by a number of moths, butterflies, squirrels and birds, especially grouse. Although the trees do not grow large in diameter, the wood of the hop hornbeam has been used for tool handles, fence posts and canes. Ironwood makes excellent firewood because it cures well and burns hot.
The American hornbeam is a low-growing tree of the understory that can have a single or multiple stems, oftentimes having a twisted appearance. The American hornbeam has smooth, grayish-blue bark with deep furrows. The appearance of the bark gives rise to two of the more common names, blue beech or muscle wood, since the bark looks like a muscular arm.
The muscle wood prefers a deep, rich, moist soil and is usually found alongside small streams in heavily wooded areas. It prefers a bit more moist and shadier conditions than the ironwood, so you often see ironwood on the hillside leading down to the stream while the muscle wood are found along the more level sections near the water.
Muscle wood has winged nutlets that form in late summer, and this tree provides much in the way of food for many forest-dwelling animals. Muscle wood has a hard, dense, white wood that has been used for tool handles, canes and bowls. The heavy, dense wood makes good first-season firewood, but it will get soft and punky if left on the firewood stack too long.
Muscle wood is used as an ornamental, but it is prone to sunscald so it is best planted in shady, moist conditions. This small tree has few insect or disease pests and has a very vibrant orange to bright yellow fall foliage. There are three separate species of muscle wood that grow in North and Central America.
Nature Notes is compiled by Ginny Brace. Contact her at firstname.lastname@example.org.