pignut hickory (Carya glabra)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

COMMON NAMES:
pignut hickory
broom hickory
red hickory
swamp hickory
sweet pignut hickory
smoothbark hickory
coast pignut hickory
pignut
false shagbark

 

SCIENTIFIC SYNONYMS:
Carya austrina (Small) Murrill
Carya leiodermis Sarg.
Carya magnifloridana Murrill
Carya megacarpa Sarg.
Carya microcarpa Nutt.
Carya ovalis (Wangenh.)

 

CONFIRMATION STATUS: Confirmed.

 

TAXONOMy: The currently accepted scientific name of pignut hickory
is Carya glabra (P. Mill.) Sweet. It is a member of the walnut family
Juglandaceae. Three varieties are commonly recognized: 1) Carya glabra
var. glabra, 2) Carya glabra var. hirsuta (Ashe) Ashe, and 3) Carya glabra
var. megacarpa (Sarg.) Sarg. The variety hirsuta, or alternately a fourth
variety identified as Carya glabra var. odorata (Marsh.) Little, is frequent-
ly considered synonymous Carya ovalis, red hickory. The taxonomic rela-
tion- ship between Carya glabra and Carya ovalis is particularly difficult,
and many taxonomists prefer to treat these sympatric taxa as a complex.
A few authorities delineate red hickory as a separate species, Carya ovalis
(Wang.) Sarg. Principal differences are in the morphology of husks or fruit;
distinctions between the two entities become apparent only during the fall.
Many intermediates have been reported; some authorities treat Carya
ovalis as an interspecific hybrid between Carya glabra and Carya ovata.

Carya leiodermis Sarg., swamp hickory, is now placed in synonymy with
Carya glabra. Pignut hickory hybridizes with butternut hickory (Carya
cordiformis). Demaree hickory, Carya X demareei Palmer, is a hybrid
product of pignut hickory and butternut hickory.

 

Characteristics which distinguish varieties of pignut hickory are as
follows: 1) var. megacarpa - larger leaves and fruit., 2) var. hirsuta -
obovoid fruit; lower leaflets; densely pubescent.,and 3) var. glabra -
usually five leaflets; husk indehiscent or splitting to the middle.

 

NATIVE STATUS: Native, United States and Canada.

 

GENERAL BOTANICAL CHARACTERISTICS: Pignut hickory is a
slow-growing deciduous tree which reaches 65 to 98 feet (20-30 m) in
height and 11 to 39 inches (30-100 cm) in diameter. On extremely favor-
able sites, individuals may reach 131 feet (40 m) in height. Pignut hickory
is characterized by a narrow oblong crown and somewhat pendulous branch-
es. The gray bark is shallowly ridged and furrowed. Plants generally
possess a pronounced taproot but few laterals. Pignut hickory is mono-
ecious. Pistillate flowers are borne in two- to five-flowered spikes, which
develop on the shoots of the current year. Slender, staminate catkins aver-
aging 2 to 3.1 inch (5-8 cm) in length are borne from the axils of leaves on
the previous season or from the inner buds of terminal scales on the cur-
rent year's growth. The fruit of pignut hickory is a hard, pear-shaped nut.
The nut is thick-shelled and approximately 0.6 to 1.4 inches (1.5-3.5 cm)
in length. The husk splits about halfway to the base. The small kernel is
sweet to bitter.

 

REGENERATION PROCESSES: Pignut hickory begins producing seed
at approximately 30 years of age; maximum seed production generally
occurs between 75 and 200 years of age. Maximum age of seed produc-
tion is approximately 300 years. Good seed crops occur at 1- or 2-year
intervals, but may be reduced by frost, insects, and seed-eating birds and
mammals. Seed is dispersed by gravity and by birds and mammals. Mam-
mals such as squirrels and chipmunks are typically more effective disper-
sal agents than birds.

 

Seeds rarely remain viable in the forest floor for more than one winter.
Early seedling growth is typically slow.

 

Pignut hickory sprouts from the root or stump after plants are cut or top-
killed by fire. Researchers have reported that sprouting is not as prolific
as in other deciduous tree species but sprouts that are produced are vigor-
ous and grow rapidly in height. Sprouts may be killed by drought, frost,
fire, or herbivory, but roots often survive and sprout from dormant buds
located near the root collar or lower part of the stem.

 

SITE CHARACTERISTICS: Pignut hickory grows in mesic to xeric
mixed woodlands, bottomland woodlands, wet hammocks, on stable dunes,
and rocky hillsides. It is a common component of southern mixed hard-
wood forests, flatwoods, and eastern redcedar (Juniperus virginiana). It
is also common but rarely abundant in oak-hickory forests.

 

Pignut hickory grows best on light, well-drained, loamy soils. Soil fertility
is variable. It occurs on soils derived from a variety of metamorphic and
sedimentary parent materials including limestone, granitic-basic and mica
schist-phyllite, glacial till, and shale.

 

SUCCESSIONAL STATUS: Pignut hickory is tolerant of shade in the
Southeast, but relatively intolerant in the northeastern portion of its range.
It grows as a common codominant in climax communities of the North
Carolina Plain and occurs in climax hammock communities of Florida. In
parts of Florida, early seral pine-oak-hickory forests are replaced by
mature oak-hickory stands. Species such as southern magnolia, beech,
cabbage palmetto, and redbay may ultimately assume prominence, but
long-lived dominants such as pignut hickory commonly persist in climax
stands. Pignut hickory grows in climax white oak-hickory forests of south-
western Ohio, in old-growth oak-hickory forests of southern Michigan,
and in low-elevation climax stands in parts of the southern Appalachians.

Heavy-seeded species such as pignut hickory are generally slow to invade
new areas. However, pignut hickory, along with various oaks (northern red
oak, black oak, white oak), may replace early seral gray birch (Betula
populifolia)-eastern redcedar stands in oldfield communitites of New York.
More shade-tolerant species such as red maple (Acer rubrum) may ulti-
mately replace oak and hickory. In some portions of the Appalachian High-
lands, hickory may ultimately replace chestnut killed by chestnut blight.

 

SEASONAL DEVELOPMENT: Across most of its range, pignut hickory
flowers in April or May. Staminate flowers typically develop before the
pistillate flowers. Fruit ripens during September or October as the husk
splits part way to the base. Seed dispersal occurs from September through
December.

 

GENERAL DISTRIBUTION: Pignut hickory grows from eastern Maine
westward to southern Michigan, Illinois, and southeastern Iowa. It extends
southward to eastern Texas, Louisiana, and Arkansas, and eastward to cen-
tral Florida. It is common but not abundant throughout much of eastern
North America. Pignut hickory reaches greatest abundance in the Ohio
River Basin and is the most common hickory of the Appalachian Mountains.
The varieties glabra and megacarpa occur sympatrically throughout most
of eastern North America south to Louisiana; the variety hirsuta occurs
throughout much of the Southeast.

 

SKY MEADOWS DISTRIBUTION:

 

Tree specimens can be found on trails marked in red.

 

       Bleak House
       Appalachian Trail/Old Trail
       South Ridge/North Ridge
       Gap Run
       Snowden
       Woodpecker Lane

       Sherman's Mill
       Rolling Meadows/ Lost Mountain
       Fish Pond

 

HABITAT TYPES AND PLANT COMMUNITIES: Pignut hickory
codominates certain upland hardwood forests of eastern North America.
Common codominants include white oak (Quercus alba) and northern
red oak (Quercus rubra).

 

Various oaks, including post oak (Quercus stellata), southern red oak
(Quercus falcata), black oak (Quercus velutinus), northern red oak, white
oak, chestnut oak (Quercus prinus), and blackjack oak (Quercus mari-
landica), are common overstory associates. Shortleaf pine (Pinus echinata),
loblolly pine (Pinus taeda), bald cypress (Taxodium distichum), sweetgum
(Liquidambar styraciflua), and water tupelo (Nyssa aquatica) also grow
with pignut hickory. Southern magnolia (Magnolia grandiflora), cabbage
palmetto (Sabal palmetto), and redbay (Persea borbonia) are particularly
common overstory associates in the South, whereas sugar maple (Acer
saccharum), red maple (Acer rubrum), black birch (Betula lenta), and
yellow birch (Betual alleghaniensis) frequently grow with pignut hickory
in the northern portion of its range.

 

Understory associates of pignut hickory are both numerous and diverse
and vary according to site and location. In portions of the South, flowering
dogwood (Cornus florida), sourwood (Oxydendrum arboreum), muscadine
grape (Vitus rotundifolia), blueberries (Vaccinium spp.), rhododendron
(Rhododendron spp.), and common greenbrier (Smilax rotundifolia) are
common associates.

 

IMPORTANCE AND USES: White-tailed deer occasionally browse pig-
nut hickory, and small mammals may eat the leaves. Pignut hickory nuts
provide food for the fox squirrel in many areas and are preferred by the
gray squirrel during fall and winter in parts of New York. Hickory nuts
may comprise up to 10 to 25 percent of squirrel diets in some locations.
The eastern chipmunk relies on hickory nuts for 5 to 10 percent of its diet.
Hickory nuts are also eaten by the black bear, gray fox, raccoon, red
squirrel, pocket mouse, woodrat, and rabbits. Hickory nuts are utilized by
black bears at lower elevations in parts of New England during the fall;

the abundance of such mast crops can affect black bear reproductive

success during the following year. Value to fur and game mammals is good. Hickory nuts are eaten by many birds including the woodduck, ring-necked

pheasant, northern bobwhite, wild turkey, common crow, bluejay, white-

breasted nuthatch, red-bellied woodpecker, and yellow-bellied sapsucker.

The value of hickory nuts to upland game birds and songbirds is fair.

 

Pignut hickory presumably provides cover for a variety of birds and mam-
mals. Many hickories are used as den trees by several species of squirrels.

Pignut hickory may have potential value for use on some types of disturb-
ed sites. It recolonizes abandoned strip mines in Maryland and West
Virginia.

 

Pignut hickory wood is heavy, hard, strong, tough, and elastic. Early uses
included broomhandles, skis, wagon wheels and, early automobile parts.
Sporting goods, agricultural implements, and tool handles are made from
the wood of pignut hickory. Specialty products include shuttle blocks,
mallets, and mauls.

 

 

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