Mockernut hickory (Carya tomentosa): 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 tomentosa (Lam.) Nutt. in USDA PLANTS, walnut family
Other names	Mockernut, white hickory, whiteheart hickory, hognut and bullnut (Silvics)
Native status, USDA PLANTS	Native in the lower 48 states
Size, Silvics	Usually 15 to 24 m (50 to 80 ft) tall and 46 to 61 cm (18 to 24 in) in diameter at breast height; occasionally about 30 m (100 ft) tall and 91 cm (36 in) across, with a dense crown
Longevity, Silvics	Described as long lived, sometimes reaching the age of 500 years; the handbook calls it the most abundant of the hickories
Green weight of the wood, NRS-38	65 lb per cubic foot, without bark

Native range and sites

The Silvics of North America handbook (Agriculture Handbook 654, volume 2, 1990) says mockernut hickory grows from Massachusetts and New York west to southern Ontario, southern Michigan and northern Illinois, then to southeastern Iowa, Missouri and eastern Kansas, south to eastern Texas and east to northern Florida. It notes that the species is not present in New Hampshire and Vermont as previously mapped. Mockernut is most abundant southward through Virginia, North Carolina and Florida, where it is the most common hickory, and also abundant in the lower Mississippi Valley, growing largest in the lower Ohio River Basin and in Missouri and Arkansas.

On sites, the handbook says it is found in the north on drier ridges and hillsides, grows best on deep, fertile soils, and in Alabama and Mississippi grows on sandy soils with shortleaf pine and loblolly pine. It places the species mainly on Ultisols, about 65 percent of its range.

Flowers, fruit and growth

Silvics says mockernut is monoecious, with male catkins about 10 to 13 cm (4 to 5 in) long and flowers that bloom from April to May depending on latitude and weather. The fruit is solitary or paired and globose, ripening in September and October, with a thick, four-ribbed husk 3 to 4 mm (0.11 to 0.16 in) thick that usually splits from the middle to the base. The nut is distinctly four-angled with a very hard shell 5 to 6 mm (0.20 to 0.23 in) thick around a small edible kernel; the handbook says the kernels are rarely eaten by people because of their size.

The handbook prints height by age for the Cumberland Mountains: 10.1 m (33 ft) at age 40 and 20.1 m (66 ft) at age 100. It says dominant and codominant hickories 38 to 51 cm (15 to 20 in) across grew about 3 mm (0.12 in) of diameter per year on good oak sites, slow compared with northern red oak, yellow-poplar, black cherry and sugar maple.

Roots

The handbook says hickories such as mockernut develop a long taproot with few laterals and that the species is windfirm. The taproot typically reaches 30 to 91 cm (12 to 36 in) in the first year and may reach 122 cm (48 in) in the second. By age 5 the root system has reached its full depth, and the roots spread sideways about twice as far as the crown.

Wood

The Wood Handbook (FPL-GTR-282, 2021) names mockernut among the true hickories most important commercially; the group description is set out once on the shagbark hickory page. Silvics adds that hickory species are preferred for fuelwood, that mockernut has the second highest heating value among the hickories, and that it is the preferred wood for smoking hams. Table 5-3b has a separate mockernut row, shown below.

Wood Handbook Table 5-3b	Specific gravity	Modulus of rupture (lbf per square inch)	Side hardness (lbf)
Green	0.64	11,100	1,440
At 12% moisture content	0.72	19,200	1,970

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 mockernut is not subject to severe loss from disease, and that most fungi cause little, if any, decay in small, young trees.

Fire. The handbook calls mockernut extremely sensitive to fire because of the low insulating capacity of its hard, flinty bark.
Trunk rot. The main fungus of hickory is Poria spiculosa, a trunk rot that the handbook says kills the bark, which produces a canker, and causes heart rot and decay.
Streaks. Mineral streaks and sapsucker-induced streaks degrade the lumber.
Foliage diseases. Leaf mildew and witches' broom (Microstroma juglandis), leaf blotch (Mycosphaerella dendroides), pecan scab (Cladosporium effusum) and anthracnose (Gnomonia caryae).
Nut pests. The hickory nut weevil (Curculio caryae), which Silvics says can destroy 65 percent of the hickory nut crop, plus another weevil on young shoots and leaf petioles, hickory shuckworms and two casebearers.
Hickory bark beetle. Scolytus quadrispinosus attacks mockernut especially in drought years and where hickories are growing rapidly. The handbook says it probably destroys more sawtimber-size mockernut than any other insect.
Borers and girdlers. The hickory spiral borer, the pecan carpenterworm, the living-hickory borer, the twig girdler (Oncideres cingulata) and a list of borers found on dying or dead trees and cut logs. Powderpost beetles are named for severe damage to hickory lumber and manufactured products.
Sap feeders and leaf feeders. Gall insects (Caryomyia species), the fruittree leafroller, the hickory leafroller, the giant bark aphid and the European fruit lecanium.

Silvics also says mockernut is not easily injured by ice glaze or snow, but that young seedlings are very susceptible to frost.

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.