The Common Oaks: The Major Quercus Tree Species of North America

Oak Trees in the Beech of Fagaceae Family

Mighty Oak

 Peter Chadwick LRPS/Getty Images

The term oak can be used as part of the common name of any of about 400 species of oak trees and shrubs in the genus Quercus (from Latin "oak tree"). The genus is native to the northern hemisphere and includes deciduous and even evergreen species extending from cold latitudes to tropical Asia and the Americas. They can be long-lived (hundreds of years) and large (70–100 feet high); they're excellent wildlife feeders due to their production of acorns.

Oaks have spirally arranged leaves, with a lobed margin in many species. Other oak species have serrated (toothed) leaves or have smooth leaf margins, which are also called entire leaves.

Oak flowers are catkins and are seen falling in late spring. Acorns produced from these flowers are borne in a cup-like structure known as a cupule. Every acorn contains one seed (rarely two or three) and takes six to 18 months to mature, depending on the species.

The "live oaks" (oaks with evergreen or extremely persistent leaves) are not necessarily a distinct group, as their members are scattered among the species below. Oaks can, however, be divided into red and white oaks, distinguished by the hue of the tight-grained wood when cut.

Identification

In summer, look for alternate, short-stalked, often lobed leaves, though they do vary in shape. Trees will have bark that's gray and scaly or blackish and furrowed. Twigs are slender with a star-shaped pith, and acorns will be nearby on the ground in the fall. Not all acorns will have their cap, and a tree drops them over about a month's time. When a tree is stressed, it'll drop some while still green over the summer, as if conditions aren't right for the tree to be able to support all the fruit on its branches, it'll discard what it won't have enough energy to ripen.

You can identify oaks in the winter by the five-sided pith of the twigs; clustered buds at the tip of a twig; slightly raised, semicircular leaf scars, which is where the leaves had been attached to the branch, and the individual bundle scars on them. Live oaks and water oaks retain most of their leaves over the winter in the South. Also look for acorns persistent on twigs or dropped under the tree.

Red oaks commonly have large leaves (at least 4 inches long) that have points to their lobes, with veins that extend all the way to the edges. Leaves are generally symmetrically shaped. Indentations run the gamut, with either dramatic indentations or none at all.

White oaks often have rounded lobes on their leaves, and indentations vary widely on these species, too.

01
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Black Oak

Black oak tree (Quercus kelloggii) in field, spring

Gary Vestal/Getty Images

Black oaks inhabit the Eastern half of the United States, except Florida, and grow 50 to 110 feet tall, depending on location. They can tolerate some poor soils. Leaves are shiny or glossy-looking with five to nine lobes that terminate in one to four teeth. Bark is dark gray to near black. Their habitat is from Ontario, Canada, to the panhandle of Florida.

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Bur Oak

A bur oak

 Chiselwit/Wikimedia Commons

The bur oak extends from Saskatchewan, Canada, to Texas, to Montana, and grows up to 80 feet tall, with a wide crown, though it's more shrubby at the northernmost and easternmost reaches of its habitat. It's one of the most drought-resistant oaks. Leaves are elliptical with five to seven rounded lobes. Scales on the acorn cap where it meets the nut form a fuzzy fringe, and the cap covers half to most of the nut.

03
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Cherrybark Oak

Cherrybark oaks can often reach 100 feet and are fast-growing. Shiny, dark green leaves have five to seven lobes that spread at right angles from the center and that end in one to three teeth. The acorn cap covers a third to half of the round nut. The tree lives from Maryland to Texas and from Illinois to the panhandle of Florida.

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Chestnut Oak

Chestnut oak

hspauldi/Flickr

The chestnut oak easily reaches 65 to 145 feet tall. Leaves hardly have any indentations, making them look almost serrated (with 10 to 14 teeth) instead of lobed. The acorn cap has gray scales with red tips, enclosing from a third to a half of an oval nut. The tree can be found in rocky, upland forests and dry soil from Ontario and Louisiana to Georgia and Maine.

05
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Laurel Oak

Laurel oaks don't have your typical "oak-looking" leaf but rather those that resemble its namesake of laurels; they're narrow blades. The acorns on this large tree (reaching 100 feet in height) are dark brown to black, only a 1/2 inch long, with a cap that covers up to 1/3 of the nut.​

06
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Live Oak

Taken at Oak Alley Plantation

Amy Hudechek/Getty Images 

Live oaks are among the oaks that are evergreen, as their habitat is in the South. If you've seen iconic images of huge trees living in sandy soils draped in Spanish moss, you've likely seen a live oak. They can live hundreds of years and grow quickly when young, to 40 to 80 feet with a spread 60 to 100 feet as well. They have short, skinny leaves and dark brown to almost black oblong acorns.

07
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Northern Red Oak

Northern Red Oak

Zen Rial/Getty Images 

Northern red oaks grow from 70 to 150 feet tall and have red-orange, straight-grained wood. They're fast-growing and hardy, tolerant of compacted soil. Leaves have seven to 11 lobes with one to three teeth, with indentations less than halfway to the center. The acorn cap covers about half of the oblong or oval nut. They grow from Maine to Michigan to Mississippi.

08
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Overcup Oak

Overcup oaks are slow-growing trees that reach up to 80 feet. Dark green leaves are deeply indented and feature rounded lobes with one to three teeth and may be shiny. The underside is grayish green and has a whiteish bloom that comes off when rubbed. Acorns are light brown and oblong with a cap that covers most of the nut. The trees reside in poorly draining lowlands in the Southern coast and along rivers in the South and West.

09
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Pin Oak

Formal Garden with Cor-ten Steel Planters with Pin Oak

 Francois De Heel/Getty Images

On the pin oak, you'll notice that the lower branches are downward sloping. The tree grows 60 to 130 feet tall. Its inner bark is pink. Leaves have deep indentations between five to seven toothed lobes that have one to three teeth. The cap of the acorn covers only a quarter of the round nut and has smooth scales.

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Post Oak

​The post oak, a slow-growing tree, can reach 50 to 100 feet. It has leaves with five to seven smooth lobes and indentations roughly halfway. Round acorns have wart-like marks and a cap that covers one quarter to two-thirds of the nut. The trees are found throughout the Deep South and extend from Texas to New Jersey.

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Scarlet Oak

Scarlet Oak

 Katja Schulz/Flickr

Scarlet oaks have a tolerance for drought and best grow in sandy soil. Look for C-shaped indentations between the lobes, which vary in depth even on the same tree. Narrowest lobes will have teeth. They grow 40 to 50 feet tall, have hairless, glossy acorn caps, and bark is medium gray to dark, and furrowed.

12
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Shumard Oak

Shumard Oak Tree

F. D. Richards/Flickr

The Shumard oak is one of the largest Southern red oaks. It reaches up to 150 feet and resides in well-draining soils near streams and rivers, Ontario to Florida to Nebraska and Texas. Leaves have five to nine lobes with two to five teeth and deep indentations—more than halfway in. The acorn cap covers up to a third of the oblong nut.

13
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Southern Red Oak/Spanish Oak

Southern red oaks, sometimes called Spanish oaks, grow from New Jersey to Florida and west to Oklahoma and Texas, reaching 70 to 100 feet high. Leaves have only three lobes, not evenly spaced. The species prefers sandy soil. The rounded, brown acorn has a downy cap that covers up to a third of the nut.

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Swamp Chestnut Oak

Swamp Chestnut Oak

 Chris M Morris/Flickr

Swamp chestnut oaks can grow anywhere from 48 to 155 feet high and prefer moist soils of well-draining floodplains in the central and Southern forests, from Illinois to New Jersey, Florida to Texas. Leaves are wide and wavy and look more like serrated leaves, featuring from nine to 14 rounded teeth and a pointed tip. Acorns are brown and egg-shaped, and their caps are shaped like bowls.

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Water Oak

Water oak trees have leaves that are mostly retained through the winter, as their habitat is in the Deep South and extends from Texas to Maryland. They're rapidly growing shade trees that can reach 100 feet high. Leaves are shaped more like neckties rather than the leaves of many other species that have indented and lobed leaves. Acorn caps cover up to only about a quarter of the round nut.

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White Oak

Swamp White Oak bark

Scientifica/Getty Images 

White oaks are long-lived shade trees that grow to 60 to 150 feet tall. Leaves have rounded lobes that can be deeply indented and are grayish green and widest nearer the end. Acorn caps are light gray and enclose only about a quarter of the light brown oblong nut. They're found from Quebec, Ontario, and Minnesota to Texas, Florida, and to Maine.

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Willow Oak

Willow Oak

USCapitol/Flickr

 Willow oaks have leaves that may not look like what you imagine "typical" oak leaves to be. They're thin and straight and only about an inch wide, with no lobes. The trees grow up to 140 feet tall and are found by rivers primarily in the Deep South. Dark-colored acorns have faint stripes.