Shellbark hickory (Carya laciniosa): what the agencies record

This page reports what US federal publications say about one tree. It does not identify trees from descriptions or photos and does not say what should be done with any tree. The family overview, tree species in the agency records, explains the sources and holds the comparison table.

At a glance

Item	What the source records
Scientific name	Carya laciniosa (Michx. f.) G. Don in USDA PLANTS, walnut family
Other names	Shagbark hickory, bigleaf shagbark hickory, kingnut, big shellbark, bottom shellbark, thick shellbark and western shellbark (Silvics)
Native status, USDA PLANTS	Native in Canada and the lower 48 states
Size, Silvics	Occasionally grows to a height of 40 m (131 ft) and a diameter of 100 cm (39 in); a Missouri specimen tree is reported at 117 cm (46.2 in) in diameter, 36.9 m (121 ft) tall with a spread of 22.6 m (74 ft)
Life habit, Silvics	A slow-growing, long-lived tree, hard to transplant because of its long taproot; the nuts are the largest of all hickory nuts
Green weight of the wood, NRS-38	64 lb per cubic foot, without bark

Native range and sites

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) says shellbark hickory is widely distributed but nowhere common. It records a range from western New York through southern Michigan to southeast Iowa, south through eastern Kansas into northern Oklahoma, and eastward through Tennessee into Pennsylvania. The species is most prominent in the lower Ohio River region and south along the Mississippi River to central Arkansas, and the handbook says it is frequently found in the great river swamps of central Missouri and the Wabash River region in Indiana and Ohio.

On sites, Silvics says shellbark grows best on deep, fertile, moist soils and does not thrive in heavy clay, but grows well on heavy loams or silt loams. It calls the species essentially a bottomland tree, often found on river terraces and second bottoms, that requires moister situations than pignut, mockernut or shagbark hickory, although it is sometimes found on dry, sandy soils. Land flooded shallowly for a few weeks early in the growing season is described as favorable.

Flowers, fruit and growth

Silvics says shellbark is monoecious and produces flowers from April to June after the leaves appear, with wind-carried pollen and fruit ripening from September to November. The hickories as a group grow slowly in diameter. The handbook gives about 2 mm (0.08 in) per year for sapling-size trees, rising to about 3 mm (0.12 in) per year as poles and sawtimber, and about 5 mm (0.20 in) per year for second-growth trees.

Roots

The handbook says shellbark develops a large taproot that penetrates deeply, with lateral roots emerging at nearly right angles and no distinct major laterals. Root growth measured in Illinois was rapid in April, slowed in July and August, increased again in September and ended in late November. The only fungus the handbook names from the roots is a mycorrhizal partner, Laccaria ochropurpurea.

Wood

The Wood Handbook (FPL-GTR-282, 2021) names shellbark among the true hickories most important commercially; what it says about the group is set out once on the shagbark hickory page. Silvics says the wood of shellbark is hard, heavy, strong and very flexible, a favored wood for tool handles, and lists furniture, sporting goods, veneer, fuelwood and charcoal. It adds that a few plantations have been established for nut production, but that the nuts are difficult to crack even though the kernel is sweet. Table 5-3b has a separate shellbark row, shown below.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.62	10,500	1,670
At 12% moisture content	0.69	18,100	1,810

The Wood Handbook states that specific gravity is based on oven-dry weight and the volume when green or at 12% moisture content. The green weight of the wood without bark is in the NRS-38 table, the same figure used in the log weight calculator.

Diseases, insects and damage the handbook names

Silvics (1990) says that although numerous insects and diseases affect hickories, shellbark hickory has no enemies that seriously threaten its development or perpetuation as a species. It also says shellbark is free of serious diseases, though it is a host for a variety of fungi: more than 130 have been identified from species of Carya, including leaf disease, stem canker, wood rot and root rot fungi, and the handbook says specific information for shellbark is not available.

Seed pests. The pecan weevil (Curculio caryae) and the hickory shuckworm (Laspeyresia caryana), named as two of the most important insects that reduce seed production.
Hickory bark beetle. Scolytus quadrispinosus feeds in the cambium and, the handbook says, seriously weakens or even kills some trees.
Borers. The hickory spiral borer (Agrilus arcuatus torquatus), whose larvae feed beneath the bark and can be very destructive to seedlings; the flatheaded appletree borer (Chrysobothris femorata); and the living-hickory borer (Goes pulcher), which feeds in trunks and branches. Standing dead trees and freshly cut logs are described as highly susceptible to many wood borers.
Twig girdler. Oncideres cingulata, which can seriously affect reproduction by killing back the tops of seedlings and sprouts.
Foliage feeders and weather. A large number of insects feed on the foliage and may cause some stem deformity and growth loss. Silvics says shellbark is susceptible to bole injury from fire, with fire injuries often invaded by wood rot fungi, is resistant to snow and ice damage, and is susceptible to frost damage.

The guide on reporting a pest in the United States and the Canada reporting page give the offices that take sightings of regulated pests. Who may apply pesticides is in pesticide licences by country.