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| ## american hornbeam {#american-hornbeam .Title-Header}               |
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| *Carpinus caroliniana* Walt.                                          |
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| Plant Symbol = CACA18                                                 |
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####### *Contributed By: USDA NRCS National Plant Data Center & the Biota of North America Program*

![](media/image2.jpeg){width="2.5972222222222223in" height="3.9in"}

### Alternate Names

Ironwood, musclewood, muscle beech, blue beech, water beech

### Uses

The wood of *Carpinus* is of minor economic importance because of the
small size of the trees. It is whitish, extremely hard, and heavy and
has been used for making mallet heads, tool handles, levers, and other
small, hard, wooden objects. The wood is not subject to cracking or
splitting and was used by American pioneers for bowls and dishes.

American hornbeam is planted in landscapes and naturalized areas. It
prefers deep, fertile, moist, acidic soil and grows best in partial
shade, but will

grow in full sun. Its chief liabilities in cultivation are a relatively
slow growth rate and difficulty in transplantation. It is not
drought-tolerant.

Seeds, buds, or catkins are eaten by a number of songbirds, ruffed
grouse, ring-necked pheasants, bobwhite, turkey, fox, and gray
squirrels. Cottontails, beaver, and white-tailed deer eat the leaves,
twigs, and larger stems. Beaver heavily uses American hornbeam, because
it is readily available in typical beaver habitat.

### Status

Please consult the PLANTS Web site and your State Department of Natural
Resources for this plant's current status, such as, state noxious status
and wetland indicator values.

### Description

*General:* Birch Family (Betulaceae). American hornbeam is a native,
large shrub or small tree with a wide-spreading, flat-topped crown, the
stems slender, dark brown, hairy; bark gray, thin, usually smooth, with
smooth, longitudinal fluting (resembling a flexed muscle). Its leaves
are deciduous, simple, alternate, ovate to elliptic, 3-12 cm long, with
doubly-serrate edges, dark green, turning yellow to orange or red in the
fall, glabrous above, slightly to moderately pubescent beneath,
especially on major veins, with or without conspicuous dark glands. The
flowers are unisexual, in catkins, the male (staminate) catkins 2-6 cm
long, female (pistillate) catkins 1-2.5 cm long, both types on the same
plant (the species monoecious). Fruits are a nutlet 4-6 mm long,
subtended by a 3-winged, narrow, leaf-like bract, numerous nutlets held
together in pendulous chain-like clusters 2.5-12 cm long, changing from
green to brown in September-October. The common name, beam, is an Old
English word for tree, with horn suggesting an analogy of the hard,
close-grained wood to the tough material of horns.

*Variation within the species*: the two subspecies are distinguished by
morphology and geography. They hybridize or intergrade where their
ranges overlap in a broad band running from the Carolinas south to
northern Georgia and westward to Missouri, Arkansas, and southeastern
Oklahoma. Plants with intermediate features are also found throughout
the highlands of Missouri and Arkansas.

1\. Leaf blades narrowly ovate to oblong-ovate, 3-8.5(-12) cm long,
acute to obtuse at the tip; secondary teeth blunt and small; lower
surfaces without small dark glands; southern Atlantic and Gulf of Mexico
coastal plains and also extends northward in the Mississippi Embayment.
\...\...\...\.... subsp. *caroliniana*

2\. Leaf blades ovate to elliptic, mostly 8-12 cm long, usually abruptly
narrowing at the tip, sometimes long and gradually tapered; secondary
teeth sharp-tipped, often almost as large as primary teeth; lower
surfaces covered with tiny, dark glands; Appalachians and interior
forested northeastern North America.

\...\...\...\...\...\...\.... subsp. *virginiana* (Marsh.) Furlow

Trees of temperate forests in the mountains of Mexico and Central
America, formerly considered to be part of *Carpinus caroliniana*, are
now treated as *C. tropicalis* (J.D. Smith) Lundell spp. *tropicalis*
and *C. tropicalis* ssp. *mexicana* Furlow.

*Distribution:* Widespread in the eastern United States \-\-- from
central Maine west to southwestern Quebec, southeastern Ontario,
northern Michigan, and northern Minnesota, south to central Iowa and
eastern Texas, east to central Florida. Absent from the lowermost Gulf
Coastal Plain and the Mississippi embayment south of Missouri).

### Adaptation 

American hornbeam occurs primarily as an understory species in
bottomland mixed-hardwood forests. Best sites are in the transition
between mesic and wet areas \-- near lakes and swamps, on well-drained
terraces of rivers, terraces or steep slopes of minor streams with some
gradient, coves, ravine bottoms, and rises in lowlands. These sites
generally have abundant soil moisture but sufficient drainage to prevent
saturation and poor aeration during the growing season, although trees
may be abundant on sites flooded for up to about 20% of the growing
season. American hornbeam occurs less commonly in upland hardwood
forests and may range from 300-900 meters elevation in the Appalachian
and Adirondack Mountains. In the northeastern US, it may be an early
migrant and form pure stands in moist old fields; it may be a minor
seral component of sapling-size tree-shrub communities along the
mid-Atlantic coast. Flowering: March-May; fruiting: August-October.

### Establishment

American hornbeam begins to produce seeds at about 15 years and peaks at
25 to 50 years, probably ceasing at about 75 years. Large seed crops are
produced at 3-5-year intervals. Seeds are mainly dispersed by birds.
Seed establishment will occur on leaf litter in deep shade. Flooding,
drought, damping off, proximity to a conspecific adult, and herbivory
are important causes of mortality for first-year seedlings. Reproduction
also may occur by sprouts from the root crown and by root sprouts,
although the latter apparently is not common.

American hornbeam is best suited to establishment in bottomlands that
have already been stabilized by pioneer species. It is shade-tolerant
and persists in the understory of late seral and climax communities.
Shade tolerance declines with age and American hornbeam is likely to
become dominant, with other subcanopy species, at some sites after
overstory removal.

### Management

Because of its thin bark, American hornbeam is probably either
top-killed or completely killed by most fires. It occurs mostly in
communities that rarely experience fire. It sprouts after top-kill by
fire and repeated fires at a closely spaced interval will quickly
eliminate the species. The wood rots very rapidly and dying trees
usually disappear naturally within a decade.

### Cultivars, Improved and Selected Materials (and area of origin)

Contact your local Natural Resources Conservation Service (formerly Soil
Conservation Service) office for more information. Look in the phone
book under "United States Government." The Natural Resources
Conservation Service will be listed under the subheading "Department of
Agriculture."

### References

Delcourt, H.R. & P.A. Delcourt 1994. *Postglacial rise and decline of
Ostrya virginiana (Mill.) K. Koch and Carpinus caroliniana Walt. in
eastern North America: predictable responses of forest species to cyclic
changes in seasonality of climates.* J. Biogeogr. 21:137-150.

Furlow, J.J. 1987. The *Carpinus caroliniana* *complex in North America.
I. A multivariate analysis of geographical variation.* Syst. Bot.
12:21-40.

Furlow, J.J. 1987. The *Carpinus caroliniana* *complex in North
America*. II. Systematics. Syst. Bot. 12:416-434.

Furlow, J.J. 1990. *The genera of Betulaceae in the southeastern United
States*. J. Arnold Arbor. 71:1-67.

Furlow, J.J. 1993. *Carpinus*. Pp. 531-533, IN: *Flora of North America,
north of Mexico*. Vol. 3. Oxford Univ. Press, New York.
\<http://hua.huh.harvard.edu/cgi-bin/Flora/flora.pl?FLORA_ID=12395\>

Metzger, F.T. 1990. *Carpinus carolinianus* Walt. American hornbeam. Pp.
179-185, IN: R.M. Burns and B.H. Honkala. *Silvics of North America*.
*Volume 2.* *Hardwoods*. USDA, Forest Service Agric. Handbook 654,
Washington, D.C.
\<http://willow.ncfes.umn.edu/silvics_manual/Table_of_contents.htm\>

Sullivan, J. 1994. *Carpinus caroliniana*. In: W.C. Fischer (compiler).
*The Fire Effects Information System* \[Data base\]. USDA, Forest
Service, Intermountain Research Station, Intermountain Fire Science
Laboratory, Missoula, Montana. \<http://www.fs.fed.us/database/feis/\>

Wardell, G.I. & J.E. Winstead 1978. *Population differences in bud
bursting of Carpinus caroliniana Walter.* Trans. Kentucky Acad. Sci.
39:127-130.

Winstead, J.E., B.J. Smith, & G.I. Wardell 1977. *Fruit weight clines in
populations of ash, ironwood, cherry, dogwood and maple*. Castanea
42:56-60.

### Prepared By

*Guy Nesom*

Formerly BONAP, North Carolina Botanical Garden, University of North
Carolina, Chapel Hill, North Carolina

### Species Coordinator

## *Lincoln Moore*

USDA, NRCS, National Plant Data Center, Baton Rouge, Louisiana

Edited: 17jan01 jsp;10feb03 ahv; 01jun06 jsp

For more information about this and other plants, please contact your
local NRCS field office or Conservation District, and visit the PLANTS
Web site\<[http://plants.usda.gov](http://plants.usda.gov/)\> or the
Plant Materials Program Web site
\<[http://Plant-Materials.nrcs.usda.gov](http://Plant-Materials.nrcs.usda.gov/)\>

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