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Mockernut hickory facts for kids

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Mockernut hickory
Carya tomentosa nuts USDA.jpg
The nuts of white hickory
Conservation status
Scientific classification
Genus:
Carya
Species:
tomentosa
Carya tomentosa range map 1.png
Natural range of Carya tomentosa
Synonyms

Carya alba L.

The mockernut hickory (scientific name: Carya tomentosa) is a type of tree in the Juglandaceae family, also known as the walnut family. You might also hear it called mockernut, white hickory, whiteheart hickory, hognut, or bullnut. This tree is very common in the eastern part of the U.S.. It can live for a very long time, sometimes up to 500 years!

Mockernut hickory wood is strong, hard, and flexible. People use it for things that need to be tough, like tool handles. It also makes great firewood. In the fall, its leaves turn a bright yellow color. The name tomentosa comes from a Latin word meaning "covered with dense, short hairs." This refers to the fuzzy underside of the leaves, which helps identify the tree. It's called "white hickory" because its wood is light-colored. The name "mockernut" comes from its fruit, which has a very thick shell and only a tiny bit of edible nut inside.

Where Mockernut Hickory Trees Live

Native Home of the Mockernut Hickory

The mockernut hickory tree naturally grows across a wide area. You can find it from Massachusetts and New York, west to southern Ontario in Canada, and northern Illinois. Its range extends south through southeastern Iowa, Missouri, and eastern Kansas. From there, it goes south to eastern Texas and east to northern Florida.

This tree is most common in the southern states like Virginia, North Carolina, and Florida. It's the most common type of hickory tree there. It also grows very well in the lower Mississippi Valley. The biggest mockernut trees are found in the lower Ohio River Basin, Missouri, and Arkansas.

Climate Conditions for Mockernut Hickory

Mockernut hickory trees usually grow in places with humid climates. In their natural range, the amount of rain each year varies. It can be about 890 millimeters (35 inches) in the north. In the south, it can be as much as 2030 millimeters (80 inches).

During the growing season, from April to September, the rainfall is usually between 510 to 890 millimeters (20 to 35 inches). In the northern areas, about 200 centimeters (79 inches) of snow falls each year. Snow is rare in the southern parts of its range.

Temperatures where mockernut hickories grow range from 10 to 21 degrees Celsius (50 to 70 degrees Fahrenheit) on average each year. In July, the average temperatures are 21 to 27 degrees Celsius (70 to 80 degrees Fahrenheit). In January, they range from -7 to 16 degrees Celsius (20 to 60 degrees Fahrenheit). The temperature can get much hotter than 38 degrees Celsius (100 degrees Fahrenheit). It can also drop below -18 degrees Celsius (0 degrees Fahrenheit). The growing season lasts about 160 days in the north. In the southern parts, it can be as long as 320 days.

Soils and Land for Mockernut Hickory

In the northern areas, mockernut hickory trees are often found on drier soils. These are usually on ridges and hillsides. Sometimes, they grow in moist woodlands and river bottoms. These trees grow best in deep, rich soils.

In places like the Cumberland Mountains, they grow on dry spots. This includes south and west-facing slopes or dry ridges. In Alabama and Mississippi, they grow in sandy soils. They are often found with shortleaf pine and loblolly pine trees. However, most of the useful mockernut wood comes from trees growing on moderately fertile upland soils.

Mockernut hickory mainly grows in a type of soil called ultisols. These soils cover about 65% of its range. Ultisols are low in nutrients and are usually moist. But they can be dry for part of the warm season. In the mid-Atlantic and southern areas, mockernut hickory grows on various soils. These soils are on slopes that are not too steep (25% or less). They include different types of loams, clays, and well-drained quartz sands. On steeper slopes, mockernut often grows on coarse loams.

About 15% of mockernut hickory trees grow in inceptisols. These are clay-like soils with moderate to high nutrients. They are mostly found in the Appalachian Mountains on gentle slopes. Water is available to the plants during the growing season here. In the northern Appalachians, on slopes of 25% or less, mockernut hickory grows on poorly drained loams. These soils have a hard layer called a fragipan. In the central and southern Appalachians, on similar slopes, it grows on fine loams. On steeper slopes, it grows on coarse loams.

In the northwestern part of its range, mockernut grows on mollisols. These soils have a deep, rich top layer that is more than 25 centimeters (10 inches) thick. Mollisols usually form under grass in climates with moderate to high seasonal rain.

Mockernut also grows on alfisols. These soils have a medium to high amount of nutrients. Water is available to plants for more than half the year. On slopes of 25% or less, mockernut grows on wet to moist, fine loam soils. These soils have a lot of carbonate.

Trees and Plants That Grow with Mockernut Hickory

Mockernut hickory trees are often found in oak-hickory forests and beech-maple forests. While it's a common tree, it's not usually the main tree type in these forests. However, it's an important tree that grows alongside many others.

In the central upland oak forests, mockernut often grows with:

Common smaller plants and trees growing beneath them include:

Mockernut is also found with:

In southern forests, mockernut grows with:

  • Shortleaf pine
  • Loblolly pine
  • Pignut hickory
  • Gums
  • Oaks
  • Sourwood
  • Winged elm (Ulmus alata)
  • Flowering dogwood
  • Redbud
  • Persimmon (Diospyros uirginiana)
  • Eastern redcedar (Juniperus virginiana)
  • Sumacs
  • Hawthorns (Crataegus species)
  • Blueberries
  • Honeysuckle (Lonicera species)
  • Mountain-laurel
  • Viburnums
  • Greenbriers
  • Grapes

In the loblolly pine-hardwood forests of the south, mockernut often grows in drier, higher areas with:

  • White oak (Quercus alba)
  • Post oak
  • Northern red oak (Q. rubra)
  • Southern red oak (Q. falcata)
  • Scarlet oak
  • Shagbark and pignut hickories
  • Blackgum
  • Flowering dogwood
  • Hawthorn
  • Sourwood
  • Greenbrier
  • Grape
  • Honeysuckle
  • Blueberry

In southern bottom lands, mockernut is found in swamp chestnut oak-cherrybark oak forests with:

Smaller trees in the understory include:

Mockernut Hickory Life Cycle

Reproduction and Early Growth

Flowering and Fruiting

Mockernut hickory trees are monoecious. This means they have both male and female flowers on the same tree. The male flowers are called catkins. They are about 10 to 13 centimeters (4 to 5 inches) long. They grow on branches from where leaves were last year or from the base of new shoots. The female flowers grow in short spikes at the end of new shoots.

Flowers bloom in the spring, usually from April to May. The exact time depends on where the tree is and the weather. Male flowers usually appear before the female flowers. Hickory trees produce a lot of pollen, which the wind carries to other trees.

The fruits grow alone or in pairs. They are round and ripen in September and October. They are about 2.5 to 9.0 centimeters (1 to 3.5 inches) long. The fruit has a thick, four-ribbed husk, about 3 to 4 millimeters (0.12 to 0.16 inches) thick. This husk usually splits open from the middle down to the base. Inside, the nut has four clear angles. It has a reddish-brown, very hard shell, about 5 to 6 millimeters (0.2 to 0.24 inches) thick. The nut contains a small, edible kernel.

Seed Production and Spreading

Mockernut hickory seeds are spread from September through December. A mockernut hickory tree needs to be at least 25 years old before it can produce seeds for sale. The best time for seed production is when the tree is 40 to 125 years old. They can still produce seeds up to 200 years old.

Good crops of seeds happen every two to three years. In between, there are lighter seed crops. About 50 to 75% of fresh seeds will sprout. One study found that 14 mockernut hickory trees produced about 6,285 nuts each year for six years. About 39% of these nuts were healthy. About 48% did not develop properly, and 13% were damaged by insects. The Hickory shuckworm is a major insect that can stop seeds from sprouting.

Mockernut hickory produces one of the heaviest seeds among hickory species. There are about 70 to 250 cleaned seeds per kilogram (32 to 113 per pound). Seeds are mainly spread by gravity, meaning they fall to the ground. Wildlife, especially squirrels, also help spread the seeds. Birds help too. Animals like squirrels and chipmunks often bury the seeds far from the parent tree.

New Growth from Stumps

Hickory trees can grow new shoots very well from their stumps after being cut or after a fire. As stumps get bigger, fewer of them produce new sprouts. This is likely because older stumps are larger. It's possible to manage hickory forests by cutting trees and letting new ones sprout from the stumps.

It's hard to grow new hickory trees from cuttings. Mockernut and water hickory (Carya aquatica) have been tested as root stock for pecan grafts. However, mockernut root stock grew slowly. This slowed the growth of the pecan tops. Also, these grafts rarely produced trees that bore many nuts or large nuts.

From Young Trees to Mature Trees

Growth and How Much Wood They Produce

Mockernut hickory is a large tree with a thick crown of leaves. It can sometimes grow to about 30 meters (98 feet) tall. Its trunk can be about 91 centimeters (36 inches) wide at chest height (dbh). However, most mockernut trees are usually around 15 meters (49 feet) tall. Their trunks are typically 46 to 61 centimeters (18 to 24 inches) wide.

Here is how tall mockernut hickory trees can get at different ages:

Age Cumberland Mountains Mississippi Valley
(years) (meters) (feet) (meters) (feet)
10 1.2 4 2.7 9
20 5.2 17 5.5 18
30 7.9 26 7.6 25
40 10.1 33 9.1 30
60 13.7 45 12.2 40
80 16.8 55 14.9 49
100 20.1 66 17.4 57
120 23.2 76 19.8 65
160 28.7 94 24.4 80
200 33.2 109 29.0 95

On dry sites, mockernut hickory trees grow about 1.0 cubic meter per hectare (15 cubic feet per acre) each year. In dense forests on good soil, they can grow about 2.1 cubic meters per hectare (30 cubic feet per acre) annually. Some reports show annual growth rates of 3.1 cubic meters per hectare (44 cubic feet per acre) in Ohio.

Hickory trees, including mockernut, grow slower than some other trees like northern red oak or yellow-poplar. Dominant hickory trees grow about 3 millimeters (0.12 inches) in trunk width per year. Faster-growing trees might grow 6 millimeters (0.24 inches) per year. Usually, new branches growing from the trunk (called epicormic branching) are not a big problem for hickory trees.

How Their Roots Grow

Mockernut hickories develop a long main root called a taproot. It has only a few side roots. In the first year, most of the root growth is into this taproot. It typically reaches a depth of 30 to 91 centimeters (12 to 36 inches). Small side roots grow along the taproot, but many die back in the fall. In the second year, the taproot can reach 122 centimeters (48 inches) deep. The side roots also grow quickly. After 5 years, the root system reaches its deepest point. The horizontal spread of the roots is about twice as wide as the tree's crown. By age 10, the tree's height is four times the depth of its taproot.

How They Handle Competition

Mockernut hickory trees are generally not very tolerant of shade. This means they need a lot of sunlight to grow well. However, they can recover quickly if they have been growing in shade. They are considered a "climax species" on moist sites. This means they can become a main tree type in a forest over a long time.

It's hard to get new hickory trees to grow from seeds because animals eat many of them. But if there are enough young hickory trees already, cutting down other trees (called clearcutting) can help the hickories grow. If there aren't enough young hickories, clearcutting might remove them. Hickory trees can sprout new growth from their stumps. This helps them survive if they are eaten by animals, broken, or affected by drought or fire. Young hickory trees might die back to the ground several times. But each time, a new shoot grows bigger and develops a stronger root system. This way, hickory trees gradually grow under moderately dense tree covers. This is especially true on dry sites where other trees that are sensitive to fire or drought can't grow as well.

Things That Can Harm Mockernut Hickory

Mockernut hickory trees are very sensitive to fire. Their hard bark doesn't protect them well from heat. They usually don't suffer much from diseases. The main fungus that affects hickory trees is Poria spiculosa. This fungus causes rot in the trunk. It can kill the bark, create cankers, and cause the wood to decay. This can seriously damage the tree. Mineral streaks and damage from sapsuckers can also lower the quality of the wood. Generally, the strong wood of hickories makes them quite resistant to decay fungi. Most fungi don't cause much damage to small, young trees.

Common leaf diseases include leaf mildew and witches' broom (Microstroma juglandis). There's also leaf blotch (Mycosphaerella dendroides) and pecan scab (Cladosporium effusum). Mockernut hickory can also get anthracnose (Gnomonia caryae).

The nuts of all hickory species can be attacked by the hickory nut weevil (Curculio caryae). Another weevil (Conotrachelus aratus) attacks young shoots and leaf stems (called petioles). The Curculio weevils are the most damaging. They can destroy 65% of the hickory nut crop. Hickory shuckworms also harm the nuts.

The bark beetle (Scolytus quadrispinosus) attacks mockernut hickory trees. This is especially true during dry years and when hickory trees are growing fast. The hickory spiral borer (Argilus arcuatus torquatus) and the pecan carpenterworm (Cossula magnifica) are also serious insect pests. The hickory bark beetle probably destroys more large mockernut trees than any other insect. The hickory spiral borer kills many young trees. The pecan carpenterworm damages both trees and logs. The twig girdler (Oncideres cingulata) attacks both small and large trees. It badly deforms trees by sawing off branches. Sometimes, these girdlers cut young hickory trees near the ground.

Two types of casebearers (Acrobasis caryivorella and A. juglandis) eat buds and leaves. Later, they bore into the soft hickory shoots. The larvae of A. caryivorella can destroy all the nuts on a tree. The living-hickory borer (Goes pulcher) feeds on hickory trunks and branches throughout the East. Borers often found on dying or dead hickory trees or cut logs include:

  • Banded hickory borer (Knulliana cincta)
  • Long-horned beetle (Saperda discoidea)
  • Apple twig borer (Amphicerus bicaudatus)
  • Flatheaded ambrosia beetle (Platypus compositus)
  • Redheaded ash borer (Neoclytus acuminatus)
  • False powderpost beetle (Scobicia bidentata)

Severe damage to hickory wood and products is caused by powderpost beetles (Lyctus species and Polycanon stoutii). Gall insects (Caryomyia species) often infest leaves. The fruit-tree leafroller (Archips argyrospila) and the hickory leafroller (Argyrotaenia juglandana) are the most common leaf eaters. The giant bark aphid (Longistigma caryae) is common on hickory bark. This aphid usually feeds on twigs and can cause branches to die. The European fruit lecanium (Parthnolecanium corni) is also common on hickories.

Mockernut trees are not easily hurt by ice or snow. However, young seedlings are very sensitive to frost damage. Many birds and animals eat the nuts of mockernut hickory. This, along with insect and disease problems, means that most nuts are eaten each year. Only during years with a very large nut crop are there many left.

Ecology and Uses of Mockernut Hickory

Mockernut nuts are a favorite food for many animals. Squirrels especially love to eat the green nuts. Black bears, foxes, rabbits, beavers, and white-footed mice also eat the nuts. Sometimes, they even eat the bark. White-tailed deer eat the leaves and twigs, and also the nuts. Hickory nuts are a small food source for ducks, quail, and turkeys.

Many types of birds and other animals eat mockernut hickory nuts. These include wood ducks, red-bellied woodpeckers, red foxes, squirrels, beavers, eastern cottontails, eastern chipmunks, turkeys, white-tailed deer, and white-footed mice. Many insect pests eat hickory leaves and bark.

Mockernut hickory trees also provide homes for animals. They have cavities (holes) where woodpeckers, black rat snakes, raccoons, and Carolina chickadees can live. Their thick leaves also make them good nesting trees, offering cover for birds. Animals help spread the seeds so new hickory trees can grow in other places. Chipmunks, squirrels, and birds are especially good at this. Some fungi grow on mockernut hickory roots, sharing nutrients from the soil.

Mockernut hickory wood is highly valued. It is used for lumber, pulpwood (for paper), charcoal, and other fuelwood products. Hickory wood is a top choice for burning as fuel. Mockernut has the second-highest heating value among hickory species. It can also be used for veneer (thin sheets of wood). However, there aren't many logs of the right quality for veneer.

Mockernut hickory wood is used for tool handles that need to be very strong and resistant to shock. It's also used for ladder rungs, sports equipment, farm tools, dowels, gym equipment, poles, shafts, well pumps, and furniture. Lower quality wood is used for things like pallets and blocks. Hickory sawdust, chips, and some solid wood are often used by companies to smoke meats. Mockernut is the preferred wood for smoking hams. Even though mockernut kernels are edible, people rarely eat them. This is because they are small and are usually eaten by squirrels and other wildlife.

Genetics of Mockernut Hickory

Mockernut hickory has 64 chromosomes. This means it rarely crosses with trees that have 32 chromosomes, like pecan or shellbark hickory. There isn't much published information about the genetics of this specific species. However, scientists are working to map the genome (the complete set of genetic instructions) of pecan trees. This genome map might eventually include other hickory species.

Hickory trees are known for being very varied. Many natural hybrids (mixtures of two different species) are known among North American Carya species. Hickories can usually be successfully crossed within their genus. Scientists know that mockernut hickory naturally hybridizes with C. illinoensis (creating Carya x schneckii) and C. ovata (creating Carya x collina). Mockernut also easily hybridizes with the tetraploid Carya texana. Hybrid trees often produce few nuts, or the nuts they do produce are empty inside. However, there are many exceptions to this rule.

Images for kids

  • Carya tomentosa

    Bud break

  • Carya tomentosa female flower

    Female flower

  • CaryaTomentosaBark

    Bark

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