Carya cordiformis, the bitternut hickory, also called bitternut or swamp hickory, is a large pecan hickory with commercial stands located mostly north of the other pecan hickories. Bitternut hickory is cut and sold in mixture with the true hickories. It is the shortest-lived of the hickories, living to about 200 years.
Bitternut hickory grows in moist mountain valleys along streambanks and in swamps. Although it is usually found on wet bottom lands, it grows on dry sites and also grows well on poor soils low in nutrients. The species is not included as a titled species in the Society of American Foresters forest cover types because it does not grow in sufficient numbers.
Bitternut hickory grows throughout the eastern United States from southwestern New Hampshire, Vermont, Maine, and southern Quebec; west to southern Ontario, central Michigan, and northern Minnesota; south to eastern Texas; and east to northwestern Florida and Georgia. It is most common, however, from southern New England west to Iowa and from southern Michigan south to Kentucky. It is probably the most abundant and most uniformly distributed of all the hickories.
Bitternut is used for lumber and pulpwood. Because bitternut hickory wood is hard and durable, it is used for furniture, paneling, dowels, tool handles and ladders. Like other hickories, the wood is used for smoking meat, and by Native Americans for making bows. Bitternut hickory seeds are eaten by rabbits, and both its seeds and bark are eaten by other wildlife.
Bitternut hickory is a diploid species with two sets of sixteen chromosomes that readily hybridizes with other diploid hickory species with a few named hican varieties available. The pecan variety 'Major' has bitternut alleles at two simple sequence repeat loci indicating a cryptic cross that may also have involved C. ovata.
Bitternut hickory is a large, native north American tree, best reserved for larger landscapes. It has large, compound leaves, a 1 inch, four-part nut, and yellow fall color. Like all hickories, debris from its fruit drops from late summer throughout autumn, making fall cleanup in urban areas more challenging.
Bitternut hickory prefers deep, moist, well-drained soils, but is often found in drier conditions. Transplant in spring only as it develops a long taproot, making it difficult to transplant. Like all hickories, debris from its fruit drops from late summer throughout autumn, making fall cleanup in urban areas more challenging.
Bitternut hickory is cut and sold in mixture with the true hickories. It is the shortest lived of the hickories, living to about 200 years. The dark brown close-grained hardwood is highly shock resistant which makes it excellent for tools. It also makes good fuel wood and is planted as an ornamental.
Bitternut hickory is probably the most abundant and most uniformly distributed of all the hickories. It grows throughout the eastern United States from southwestern New Hampshire, Vermont, Maine, and southern Quebec; west to southern Ontario, central Michigan, and northern Minnesota; south to eastern Texas; and east to northwestern Florida and Georgia. It is most common, however, from southern New England west to Iowa and from southern Michigan south to Kentucky (6,23,26).
Throughout the range of bitternut hickory, the mean annual precipitation ranges from 640 to 1270 mm (25 to 50 in) except for a small area in the southern Appalachians where about 2030 mm. (80 in) is common. In the northern part of the range, snowfall averages 203 cm (80 in) per year, but in the southern extreme of the range, it rarely snows. During the growing season, from April to September, the precipitation ranges from 510 to 1020 mm (20 to 40 in).
Bitternut hickory grows in moist mountain valleys along streambanks and in swamps. Although it is usually found on wet bottom lands, it grows on dry sites and also grows well on poor soils low in nutrients (10).
In the northern part of its range, bitternut hickory is found on a variety of sites. It grows on rich, loamy, gravelly soil in low wet woods, and along the borders of streams in Michigan, but it is also found on dry uplands. In the southern part of its range, bitternut is more restricted to moist sites. It reaches its largest size on the rich bottom lands of the lower Ohio River Basin. In the southeastern part of its range, bitternut grows on overflow bottom land, but in its southwestern range, it is common on poor, dry, gravelly upland soils. Bitternut is not found in the mountain forests of northern New England and New York, nor at higher elevations in the Appalachians (23).
Bitternut hickory grows primarily on Ultisols that occupy about 50 percent of its geographic range (33). These soils are low in nutrients and are found primarily in the southern to mid-Atlantic region on gentle to steep slopes. Along the mid-Atlantic, southern, and western ranges, bitternut hickory grows on a variety of soils on slopes of 25 percent or less, including combinations of fine to coarse loams and well-drained quartz sands. On slopes steeper than 25 percent, bitternut hickory grows on coarse loams.
Inceptisols occupy about 15 percent of the bitternut hickory range, dominating the Appalachian portion of the geographic range. On gently to moderately sloped topography, the hickories are found on fine loams with a fragipan. On steep slopes, they are more commonly found on coarse loams. These soils are moderate to high in nutrients and water is available to plants during more than half of the year or more than 3 consecutive months during the warm season.
Mollisols occupy an estimated 20 percent of the bitternut hickory range primarily in western areas (33). These soils typically have a dark, deep, fertile surface horizon more than 25 cm (10 in) thick. Mollisols form under grass in climates that have moderate seasonal precipitation. Bitternut grows on a variety of soil combinations such as wet, fine loams, and sandy-textured soils that often have been burned, plowed, and pastured.
Alfisols comprise about 15 percent of the bitternut range, mainly in northern and northwestern portions. These soils contain a medium to high supply of nutrients. In Minnesota and Wisconsin, bitternut hickory is found on moist, well-drained, sandy soils with slopes up to 25 percent. Near Lake Erie and in southern Illinois and northeastern Missouri, it occasionally occurs on wet to moist, poorly drained soils on slopes of less than 10 percent.
Bitternut hickory, though present throughout the eastern forest, does not grow in sufficient numbers to be included as a titled species in the Society of American Foresters forest cover types (8), but it is mentioned as an associated species in six types. With one exception, most of these types are subclimax to climax.
Because bitternut hickory occupies many sites throughout its geographic range, its associations vary. In addition to the species named in the cover types, bitternut hickory grows with various oaks (Quercus spp.) in the northern region. In the southern part of Quebec, there is a sugar maple-bitternut hickory subtype that is restricted to deep soils. Trees associated with it include basswood (Tilia spp.), eastern hophornbeam (Ostrya virginiana), northern red oak (Quercus rubra), butternut (Juglans cinerea), and black maple (Acer nigrum). In the central hardwood region, extending in to northwestern Minnesota, bitternut hickory is found with hackberry (Celtis occidentalis), green ash (Fraxinus pennsylvanica), and butternut. Common understory herbaceous stems include largeflower bellwort (Uvularia grandiflora), Virginia creeper (Parthenocissus quinquefolia), hepatica (Hepatica acutiloba), wood-nettle (Laportea canadensis), wild ginger (Asarum canadense), large flowering trillium (Trillium grandiflorum), springbeauty (Claytonia caroliniana), violets (Viola spp.), anemone (Anemone spp.), Solomons-seal (Polygonatum pubescens), and false Solomons-seal (Smilacina stellata).
In upland oak types of the central forest region, bitternut hickory is commonly associated with mockernut hickory (C. tomentosa), pignut hickory (C. glabra), and shagbark hickory (C. ovata). Other common associates are yellow-poplar (Liriodendron tulipifera), blackgum (Nyssa sylvatica), white ash (Fraxinus americana), green ash, maples, elms (Ulmus spp.), pines (Pinus spp.), and eastern hemlock (Tsuga canadensis). Important understory trees and shrubs associated with bitternut include dogwood (Cornus spp.), sassafras (Sassafras albidum), sourwood (Oxydendrum arboreum), downy serviceberry (Amelanchier arborea), redbud (Cercis canadensis), American hornbeam (Carpinus caroliniana), eastern hophornbeam (Ostrya virginiana), witch-hazel (Hamamelis virginiana), sumac (Rhus spp.), viburnums (Viburnum spp.), rhododendron (Rhododendron maximum), wild grape (Vitis spp.), greenbriers (Smilax spp.), Virginia creeper, and poison-ivy (Toxicodendron radicans). Bitternut hickory is also prominent in the southern bottom-land hardwood swamps, in the cover type Chestnut Oak-Cherrybark Oak. There it is found with shellbark hickory (C. laciniosa), shagbark and mockernut hickories, green and white ash, white oak (Quercus alba), Shumard oak (Q. shumardii), Delta post oak (Q. stellata var. paludosa), and blackgum. Understory vegetation in this area includes pawpaw (Asimina triloba), American hornbeam, flowering dogwood, painted buckeye (Aesculus sylvatica), devils -walkingstick (Aralia spinosa), redbud, American holly (Ilex opaca), dwarf palmetto (Sabal minor), southern arrowwood (Viburnum dentatum), and possumhaw (Ilex decidua). 041b061a72