What is a Pignut Hickory Tree? - Home Stratosphere

What is a Pignut Hickory Tree?

Discover interesting facts about the pignut hickory tree. Learn about its structure, growing conditions, reproduction, uses, and some of its other kinds.

The pignut hickory is a medium to large tree, that is part of the genus Carya. One of the lesser prevalent of the hickory species, the pignut produces one of the best tasting hickory nuts.

The pignut hickory nut is said to taste and smell like maple syrup and is nibbled on by a ton of forest-dwelling creatures. To learn more about Carya glabra, keep reading! If your curiosity for trees has yet to be quenched, head on over to 101 Types of Trees to keep the learning alive!

Related: Shagbark Hickory Tree | Bitternut Hickory Tree | Types of Hickory Wood

Carya Glabra

Of all the hickory trees, the pignut is both the least abundant, and the smallest. It is also referred to as the sweet pignut, coast pignut hickory, smoothbark hickory, swamp hickory, and broom hickory. The pignut hickory is a medium-sized deciduous tree that is an important part of the oakhickory forest ecosystem.

The pignut hickory gets its nickname “sweet pignut” because the small kernel that develops in its pear-shaped fruit is wonderfully sweet, many say with the scent of maple syrup. These nuts are a very important diet staple in many forest-dwelling creatures’ lives.

A close look at a pignut hickory tree's young leaves.

What Does a Pignut Hickory Tree Look Like?

Structure

Pignut hickory trees are one of the smaller of the hickories and usually grow to be between 25-30 meters in height. Their trunks will often measure less than 1 meter in diameter, and their crowns grow in a round shape, rather than expanding outward.

They possess a woody taproot system, meaning that they usually have a few roots that grow deep into the soil to obtain locked moisture, rather than laterally in shallow soil. This type of root system makes them very windfirm and resilient to storm damage. They share this type of root system with the carrot!

Bark & Branches

The bark of the pignut hickory tree is light gray and quite smooth in young trees, hence the nickname “smoothbark hickory” which is usually spoken in reference to its sibling, the shagbark hickory tree. As the tree matures, the bark will become more coarse in texture, developing interlacing scaly ridges.

Pignut hickory branches are also the shortest growing of the hickory species, usually forming an irregularly spreading and sparse crown. For this reason, the pignut hickory isn’t always the best shade tree.

Foliage

Leaves of a shagbark hickory tree.

At the end of a pignut twig, you will find a pinnately compound leaf, meaning that each leaf is composed of several leaflets. Hickory leaves turn a stunning golden-yellow color in the fall and will drop as soon as the first frost hits. They spend most of their lives a gentle green color, which is usually a lighter shade on the bottom of the leaf.

Fruit

Pignut shells on a mossy bark.

The fruit that emerges in the late summer/early fall is a pear-shaped nut that is enclosed in a thin husk. They usually come to full ripeness between September and October, and these husks will split open and drop once the nut has reached full maturity.

How do Pignut Hickory Trees Reproduce?

Pollination

The pignut hickory has monoecious flowers, meaning that the tree possesses flowers that are both male and female. The tree can become fertilized by pollinators, or through wind pollination. They have a rather long blooming season, sometimes developing as early as March to late June.

The male flowers develop at catkins, which are small staminate clusters of flowers with no petals. These pignut hickory flowers will grow in long clusters usually 3-7 inches long, and they emerge before the female flowers do (preventing self-fertilization). They are bright green in color.

The female flowers emerge as pistillate flowers and appear in spikes on peduncles. They are far less noticeable than the male flowers, but they are the same bright green color.

Once the tree is successfully fertilized, it will produce pear-shaped nuts in the early fall and will stay on the tree until they are fully ripened. From there, their protective husks will peel off (creating quite a mess for landscapers) and the oily kernel meat is ready to be nibbled on by small mammals and birds. These animals also help with the spreading of the seeds for new growth.

Root Sprouting

Flowers of a pecan tree.

Hickory trees also have this nifty method of reproduction called root sprouting. New hickory saplings are able to emerge from either the root system of a dead tree or from the stump of a recently cut down tree.

Because this is an a-sexual form of reproduction, the trees that sprout from the roots or stump will have the same genes as a the mother tree — they are basically a clone of the original tree.

Sexual Maturity

Hickory trees are very long-lived (between 200-500 years), and so it takes them quite a while of growing before they become sexually mature. Pignut hickories will usually start to bear seeds around the age of 30, though the most productive phase of production occurs between the ages of 75 – 100. They are no longer fertile after 300 years.

Once they’ve reached sexual maturity, they produce high production seed crops every 2-3 years, with lower production seed crops in the years in between. This may occur because a certain year had more frost nights than the tree liked.

Unlike other trees that produce fruit with hard shells around them, a surprisingly high amount of seeds are actually able to successfully germinate — about 50-75% of them will successfully grow into new trees.

What are Some Other Kinds of Hickory Trees?

Bitternut Hickory (Carya cordiformis)

Golden yellow autumn-foliage of the bitternut hickory tree.

This variety of hickory trees is one of the largest of the hickories, but also one of the shortest-lived. They grow to a minimum of 35 meters tall with an impressively sized canopy. They are one of the hickory species that grows a terribly bitter and inedible nut.

Southern Shagbark Hickory (carya ovata)

Southern shagbark hickory tree

This variety of hickory trees can live to be over 350 years old! It grows naturally in certain areas of the eastern United States and southeastern Canada. It has characteristically shaggy bark, grows, and very sweet and delicious nuts.

Shellbark Hickory (Carya laciniosa)

This variety of hickory is the largest of all the hickories, usually exceeding 40 meters in height! It is sometimes called a bigleaf shellbark, kingnut, or big bottom, they produce very delicious and sweet edible nuts.

Mockernut Hickory (Carya tomentosa)

Mockernut hickory tree during fall.

This variety of hickory is the most abundant of all hickories, and is incredibly long-lived — sometimes exceeding 500 years of age! They are most distinguishable by the underside of their leaves, which are covered with very soft, downy hairs. The hickory nut they produce has a very small meaty kernel that is edible.

Red Hickory (Carya ovalis)

This variety of hickory is the most uncommon of all of its relatives. They are sometimes referred to as sweet pignut hickory, and the fruit they produce contains a small kernel of nutmeat that ranges from being very bitter, to semi-sweet.

Sand Hickory (Carya pallida)

This variety of hickory grows in different kinds of habitats, which are usually in more rocky and sandy landscapes. They are native to the southeastern United States, they are the smallest of all the hickory trees and produce a semi-tasty edible nut.

Where do Pignut Hickory Trees Grow?

Hickory tree on a lakeside under spring storm clouds.

The pignut hickory grows in almost every state in the United States, but their population isn’t particularly enormous. This is because they prefer climates that are quite humid, which not all states possess. They are most prevalent in the eastern United States and the southeastern part of Canada.

They are the most prosperous in the lower Ohio river basin, but in the remainder of the United States, they can be found in these specific areas:

  • Mississippi
  • Missouri
  • southeastern Iowa
  • Alabama
  • the lower peninsula of Michigan
  • central Florida
  • southern Massachusetts
  • North Carolina

They are not as common in the provinces of Canada, but they are found in small pockets in the following areas:

  • southern Halton region
  • the western side of Lake Ontario
  • Hamilton
  • North shores of Lake Erie

What are the Growing Conditions of Pignut Hickory Trees?

Forest filled with hickory trees.

In the Appalachian forests, the pignut hickory tree prevails over all other species of hickory growth. They are a huge percentage of harvested hickories in the Ohio Valley, the Tennessee Mountains, Kentucky, and West Virginia.

Water

Beginning with water requirements, the pignut hickory prefers climates that have annual precipitation of 30-80 inches of rain. During their growing season, they will prosper in regions that have an average humidity level lingering between 70-80%.

They do not appreciate high levels of snowfall and can handle minimum temperatures of 45 degrees Fahrenheit.

Sun

Most hickory trees are considered as rather shade-intolerant trees, and the pignut is no exception. They are intermediately shaded intolerant, but they require at least 2500 hours of sunlight each year. Because they don’t grow as tall as some of their relatives, they will mostly occur in places where there isn’t much forest canopy competition.

Soil

The pignut hickory can be most likely found on side slopes and ridgetops (where they can access a ton of sunlight). They tend to grow quite well in sandy, loamy soil that is very well-drained. They are considered as being semi-nitrogen-deficient, and so are able to tolerate low levels of nitrogen (they share this quality with yellow poplar and American basswood trees).

Additionally, the pignut hickory does the noble job of improving soil health for other plant species. Their leaves contain a high level of calcium, and so when the leaves drop and decompose, all of that calcium is absorbed into the soil.

What Pests Affect the Pignut Hickory?

A closeup of hickory tree in autumn.

First and foremost, the pignut hickory is most vulnerable to fire damage. Their wood is very dense and dry, which makes it an excellent firewood option, but not very resistant to forest fires. This isn’t exactly a pest problem, but it is worth mentioning.

Luckily, the pignut hickory is not under attack by any uncontrolled disease, but it does have to deal with the hickory shuck worm (laspeyresia caryana). These worms will often get into the nuts before they are fully mature, therefore reducing the number of seeds that are available for germination.

Thanks to yellow-bellied sapsuckers and the hickory bark beetle, pignut wood will often have internal discoloration called “mineral streak”. This not only weakens the wood but makes it unattractive and not a viable candidate for commercial use.

A fungus called Poria spiculosa causes trunk rot in pignut hickories, as well as causing cankers to develop around the branches and trunk. They can become quite large, and look like an unhealed, swollen wound.

And finally, if all of those weren’t enough, the pignut hickory has to deal with a leaf disease called anthracnose (gnomonia caryae) that causes leaf spots and blotching, as well as a film of powdery mildew that covers the leaves.

This mildew seeps into the leaves and twigs and turns into a witch’s broom infection. Witches broom is a crazy cluster of uncontrolled branch growth.

How are Pignut Hickory Trees Used?

Forest during autumn.

Forest Ecology

The pignut hickory tree is most importantly used by forest-dwelling creatures. For many of them, pignut foliage and fruit make up a huge percent of their diet. For various squirrel species, 25% of their diet is composed of pignuts.

Wild turkeys, hogs, and songbirds are known to nibble on the nuts and flowers of the pignut tree, and many species of chipmunk rely on pignuts to make up 10% of their diet. White-tailed deers will eat much of the twigs, bark, and nuts of the tree as well.

The meat kernels found inside of the pignut tree nuts are super high in crude fat, sometimes reaching 80%. They also have a high sugar content, which is why they are so crucial for so many animals.

Human Cultivation

Hickory trees are well known for their usage in meat smoking. Hickory wood is very dense, burns very slowly, and doesn’t produce too much smoke or flame. For these reasons, it is the perfect wood option for meat smoking, and the pignut hickory is no exception. Hickory wood is also used in the heating of homes with wood fireplaces.

The pignut hickory isn’t commonly used as a landscaping tree because of all of the husks that drop in the fall. They create quite an enormous mess. They are not a common suburban tree, but it does occur.

Because of the denseness and rigidity of pignut wood, it has been used in the manufacturing of skis, wagon wheels, tool handles, and textile looms.

FAQs

How do you identify pignut hickory?

The easiest way to identify pignut hickory is by the bark of a young tree. It has one of the smoothest barks of the hickory trees and is light gray in color.

Its trunk will usually stand very upright, with a tight and small crown at the top. In the spring, it might be easy to identify the pignut by the long drooping clusters of catkin flowers.

What eats pignuts hickory tree foliage?

There are many animal species that rely on the fruit and foliage of the pignut hickory tree. Squirrels, chipmunks, wild turkeys, white-tailed deer, songbirds, black bears, foxes, rabbits, raccoons, and hogs, just to name a few.

Is pignut hickory good for smoking meat?

All types of hickory wood are excellent for the practice of meat smoking. The wood is dense, has a very high heat capacity, burns slowly, and doesn’t produce too much flame or smoke.

Is pignut hickory good firewood?

Hickory wood is an excellent option for firewood because the wood is dense, has a very high heat capacity, burns slowly, and doesn’t produce too much flame or smoke.

Is pignut hickory deciduous?

All species of hickory trees are deciduous, meaning that they will drop their leaves as the cold months approach this. They do this because there isn’t enough sun in the winter to enable proper photosynthesizing, and so the tree will go dormant in the winter.

Once spring arrives again, the leaves will sprout and the trees will experience an enormous growth spurt, thanks to all of the energy they’d been conserving in the bitter winter months.

Is a hickory nut a pecan?

Hickory trees produce hickory nuts. The pecan tree produces pecans. They are not the same tree, nor are they part of the same family.

How long do pignut hickory trees live?

Hickory trees are incredibly long-lived. The pignut hickory can live to be over 300 years old, whereas its relative, the shagbark hickory, can sometimes exceed 500 years! Either way, this puts all species of hickory in the old-growth category.

Are pignut hickory trees fast-growing?

Hickory trees tend to grow rather slowly, usually not more than a meter a year. But this is for good reason. In order to develop wood, the is strong and dense, this takes time. Because hickory trees are patient growers, they end up having very high-quality wood.

How tall do pignut hickories get?

The pignut hickory is one of the shorter species of the hickory tree, never usually exceeding heights of 30 meters.

Do squirrels eat hickory nuts?

Hickory nuts are actually an enormous part of the diet of many squirrel species. The fruits that hickory trees produce are very oily and are packed with crude fat and sugars.

Do hickory trees produce sap?

Almost all species of tree produce sap, though that doesn’t mean they are a viable candidate for syrup making. Sugar maples make great sap trees because their sap is very high in sugar content, whereas hickory trees have lower sugar content.

When do hickory nuts mature?

Hickory nuts usually emerge in the early summer, but don’t become fully mature until sometimes the late fall. Once this happens, the external protective husk will peel away and revels the nut kernel inside.

Do pignut hickory trees grow in cold northern climates?

The pignut hickory prefers climates that are warmer and more humid. They can be found in many parts of the eastern United States and Canada, but they will not grow in the northmost regions of North America.

Do hickory trees produce nuts every year?

Once pignut hickory has reached sexual maturity (usually around the age of 30) it will start to produce seed crops. It will produce high-production crops every 2-3 years, with less productive crops the years in between.

Scroll to Top