The blackjack oak (Quercus marilandica) is also known as the Jack oak, black oak, and barren oak. A small deciduous tree that grows 20 to 30 feet (maximum 90 feet) with a trunk diameter of 1 foot or less. It is similar to the post oak which also grows with blackjack oak, but the leaf lobes are more pronounced and not bristle-tipped. Blackjack oak is a small to medium size oak that grows best in dry to medium, well-drained soils. It is a tough tree that can grow in poor, dry soils. The leaves appear dark green and leathery that are hairy underneath and have small bristles on the tips of the edges of the leaf. Fall color consists of yellowish brown to russet. Around here in Oklahoma, the hills are lousy with blackjack oak. Not sure if it is the same tree you have there, the ones around here are lucky to get 20 feet tall. It is mostly a trash tree, decent firewood, but not a two-foot long straight piece to be found.
Uncommon small tree of uplands, most often growing on poor, dry sites. Intolerant of shade. The large, coarse leaves are club-shaped, thick, glossy above, and hairy below. Water Oak (Quercus nigra) also has club-shaped leaves, but is not otherwise similar - it's a large tree of wet areas, with much smaller, smooth leaves and less rough bark.
Like other oaks, the staminate (male) flowers are in drooping catkins.
Orange Co., NC 4/12/08.
Scotland Co., NC 4/20/05.
Fall foliage is red to brown.
Durham, NC 11/18/06.
Blackish, blocky bark of a large tree.
Oak trees are a group of hardwood trees that belong to the genus Quercus and the beech family, Fagaceae. All types of oak trees are categorized into two groups: white oak trees, and red oak trees. To identify the type of oak tree, you need to look at its bark, leaves, acorns and its general shape.
Oaks are one of the common tree species in forests and parks in temperate countries in the Northern Hemisphere. Because of their elegant stature and hardwood, oaks are a prized type of tree in any landscape.
If you’re looking for the perfect oak tree for your garden landscape or you want to identify oaks in forests, this article will help you know what to look for.
There are about 450 species of oaks, 58 of which are native to North America. Most species of oak are deciduous trees—meaning that they lose their leaves in the fall. However, among the hundreds of oak species, you’ll also find a few evergreen varieties.
Oaks are also huge trees. Some of the tallest varieties of oaks can reach up to 100 ft. (30 m) in height—some even taller. Oak trees also have a broad spread because their strong branches can grow up to 135 (41 m) long.
The fruit of the oak trees are called acorns (also called oak nuts). Acorns have a smooth leathery shell that sits in a cup called a cupule. Many oak trees start producing acorns only after 20 – 30 years and they can produce thousands of acorns a year.
Acorns are the fruit of the oak tree. Acorn is technically a type of fruit because it has a seed. Acorn is also classified as a type of nut because its outer shell is hard.
All species of oak trees are divided into two groups: white oaks (Quercus, subgenus leucobalanus) and red oaks (Quercus, subgenus Erythrobalanus). White oaks have gray-colored bark and leaves with rounded lobes without bristles. Red oaks have darker-colored bark and leaves with pointed lobes and bristles.
Red oak trees generally have lobed leaves with pointed tips and tiny bristles at the lobed tips. Their acorns take two years to mature and they have a very bitter, unpalatable taste. The leaves measure between 5” and 9” (12 – 22 cm) long.
White oak trees generally have lobed leaves that have a rounded tips and don’t have bristles. Their acorns take one year to mature and they have a sweet or slightly bitter taste. The leaves of white oaks are similar in length to red oaks.
The bark of young oak trees is smooth and has a silvery brown look. As oak trees mature, the bark becomes fissured, developing deep grooves and ridges along it. Depending on the species of oak, the bark becomes light gray (white oak species) or very dark, almost black (red oak species).
White oak leaves vs. red oak leaves: white oak leaves usually have rounded tip (left) whereas the leaves of red oak leaves generally have pointed tips (right)
Generally, oak trees can be identified by their distinctive lobed leaves. White oak leaves usually have rounded tips while red oak leaves generally have pointed tips.
White oak leaves tend to have rounded lobes and rounded tips without bristles at the lobe tip. You may also see rounded serrations along the leaf edges.
Red oak trees tend to have pointed lobed leaves with bristles at their lobe tips. There is generally a greater variety of leaf shape in species of red oak trees: some leaves have tooth-like edges whereas others have smooth edges.
White oak acorns mature faster than red oak acorns. The acorns of white oaks take one season to mature while the fruit of red oaks take about two seasons to mature.
Red oak acorns are larger and heavier than white oak acorns.
White oak acorns have a sweet or slightly bitter taste. Acorns from red oak trees have a very bitter, unpalatable taste.
To identify oak trees, look for bark that has deep fissures and ridges, giving it a scaly look. The bark color of oaks ranges from whitish-gray to dark, almost black. You can identify oak trees by their deeply lobed leaves with pointed or rounded tips.
Let’s look in detail at how to identify common types oak trees: white oaks and red oaks.
Pin oak trees grow to medium size with a maximum height of 72 ft. (22 m). The branch growth means the trunk is barely noticeable due to lower branches drooping down. The upper canopy of the pin oak is an identifying feature with its loose, spreading growth.
Oak tree bark: Immature Pin oak trees have smooth red-gray bark that gradually becomes rougher and grayer as the tree matures.
Pin oak tree bark
Oak tree leaves: Pin oaks are identified by glossy green leaves that are deeply lobed with pointed tips. Each lobe has bristled teeth, and the leaves are hairless.
Water oak trees grow up to 100 ft. (30 m) tall with leaves that don’t drop until mid-winter. The unique leaves on the water oak make it easy to identify—the dull green leaves are spoon-shaped with a slightly rounded tip and grow in clusters.
Oak tree bark: Water oak has smooth bark that becomes rough and scaly and almost black as the oak matures.
Water oak tree bark
Oak tree leaves: Water oak leaves have variation in shape—ranging from rounded like an oblong spoon to three-lobed with bristle tips.
Black oak trees grow up to 100 ft. (30 m) tall with dense foliage that grows into a sizeable flat-topped crown. Identify black oaks by their glossy green, deeply lobed leaves with U-shaped notches. This species of red oak has an orangey inner bark and dark gray outer bark.
Oak tree bark: Long shallow fissures and scaly grayish-black bark help identify the black oak.
Oak tree leaves: Black oak identification is by the shiny, deep-green leaves with U-shape notches and pointed lobes. Look for fine hairs on the underside of leaves.
Cherrybark oak tree bark and leaves
Cherrybark oaks are one of the most towering oak trees that grow to between 100 and 130 ft. (30 – 40 m). This variety of oak is also one of the fastest-growing oak trees. The name of the oak species comes from the bark, which is similar to the black cherry tree’s bark.
Oak tree bark: Cherrybark oaks have dark gray, scaly bark that is identified by narrow ridges.
Oak tree leaves: The identifying feature of cherrybark oak leaves are the haphazard arrangement of the lobes on either side of the blade. Leaves are shiny, dark green and smooth with fine hairs on the underside.
The northern red oak—also called champion oak—is a tall, upright oak tree growing up to 92 ft. (28 m), and sometimes taller. The red oak tree’s foliage is lobed but sometimes less deeply than many other red oaks. This species of oak tree is one of the most popular oak trees in North America.
Oak tree bark: The unique identifying feature of the red oak bark is the shiny stripes in the center of fissures running up the tree. Bark color is dark brown to reddish-gray.
Northern Red Oak tree bark
Oak tree leaves: Northern red oak leaves are dark green, smooth and lobed with teeth on the tips of lobes.
The scarlet oak tree is a medium-sized oak that grows to between 67 and 100 ft. (20 – 30m). The oak tree looks similar to the pin oak or black oak. However, the difference in leaf shape helps identify between the species. Scarlet oaks have lobed leaves with C-shaped notches, not U-shaped ones.
Scarlet oak tree leaves and Scarlet oak tree bark
Oak tree bark: The scarlet oak bark has irregular broad scaly ridges and fine fissures.
Oak tree leaves: Identify scarlet oak leaves by their deep lobes and C-shaped sinuses (notches between the lobes) with bristle teeth tips.
The southern red oak—also called the Spanish oak—thrives in southern states in sandy soil and full sun. The deciduous tree grows to between 82 and 100 ft. (25 – 30 m). An identifying feature of the southern red oak is the acorns, which are orangey-brown and are shorter than other oak trees.
Southern red oak acorns
Oak tree bark: Southern red oaks have dark gray bark that is ridged with scaly plates.
Oak tree leaves: Identify the southern red oak with its narrow leaves that are deeply lobed with significant gaps between the lobes.
Japanese evergreen oak tree bark and leaves
The unique identifying features of the Japanese oak is that it’s the smallest oak tree and a type of evergreen tree. This evergreen oak has a maximum height of 45 ft. (14 m). Also, the smooth, narrowly lanceolate or ovate leaves and smooth bark make the Japanese oak unlike any other species of oak tree.
Oak tree bark: Japanese oaks have dark gray smooth bark, unlike most other species of oak.
Oak tree leaves: Glossy, ovate leaves that have a finely rounded tip and long point help identify the Japanese evergreen oak tree.
The laurel oak tree is a semi-evergreen species of oak that grows to between 65 and 70 ft. (20 -24 m). This oak tree is native to the east coast of the U.S., where it thrives in soggy soil—hence its other names of water oak and swamp laurel oak.
Oak tree bark: Laurel oak bark is dark-brown with shallow fissures and rough ridges.
Laurel oak tree bark
Oak tree leaves: laurel oak has diamond-shaped shiny green leaves. Occasionally, the long narrow leaves can be lobed. The oak is also called diamond-leaf oak.
The willow oak tree is a medium-sized type of red oak tree that grows between 65 and 100 ft. (20 – 30 m) tall. Willow oaks are fast-growing trees that can grow 2 ft. (0.6 m) per year and have a dense oblong crown when mature.
Oak tree bark: Identify willow oak trees by their rough gray-brown bark that develops into narrow fissures as it matures.
Oak tree leaves: The willow oak has leaves that are smooth, narrow, lanceolate shaped, and pointed. The leaves of the willow oak help distinguish it from other species of red oak trees. Unlike other oak trees, willow oak leaves have no lobes or teeth.
Eastern White oak tree and its leaves
The eastern white oak is a massive tree that grows around 100 ft. (30 m) with a large wide, spreading canopy. The white oak is prized for its white hardwood.
Oak tree bark: The eastern oak has light grayish-white bark with thin, narrow fissures. To identify the oak tree by its bark, look for overlapping scales about halfway up the trunk.
Oak tree leaves: Large obovate leaves that have deep lobes with rounded tips.
English oak bark, leaves, and acorns
The English oak—or common oak—is a majestic oak tree growing to a height of between 40 and 70 ft. (12 – 21 m). The English oak is identified by its sizeable spreading crown and thick, hard trunk that can be between 13 and 40 ft. (4 – 12 m) in diameter.
Oak tree bark: English oak has blackish-gray bark with deep fissuring covering the thick trunk and thick branches.
Oak tree leaves: You can easily identify English oak leaves by their small, rounded lobed leaves with smooth leaf edges. English oak leaves have the classic shape of these acorn-producing trees
The post oak is a type of white oak tree that is one of the smaller species in the genus Quercus. Post oaks grow to between 33 and 50 ft. (10 – 15 m) and have a thick trunk. To identify the post oak, look for its short stature and huge spreading crown.
Oak tree bark: Thick fissured bark that is a light gray color identifies the post oak tree.
Oak tree leaves: The post oak is identified by its slightly lobed leaves that form the shape of a cross—some say, similar to the Maltese cross.
Bur oak tree leaves and acorn
The bur oak tree is a large species of white oak tree that grow up to around 100 ft. (30 m) and sometimes as tall as 160 ft. (50 m). The bur oak is one of the enormous oaks in terms of density, with trunks as large as 10 ft. (3 m) in diameter. This slow-growing oak tree grows throughout North America.
Oak tree bark: Bur oak tree has medium-gray bark with deep, narrow scales and vertical ridges.
Oak tree leaves: Bur oaks have unusually-shaped large leaves with small lobes up to half the leaf’s length and a broad rounded apex.
Sand post oak bark and leaves
The sand post oak is one of the smallest white oaks and only grows up to 40 ft. (12 m) tall. The shrub-like oak tree thrives in southeastern states in sandy soil.
Oak tree bark: Sand post oak trees have gray bark with shallow fissure and scaly ridges.
Oak tree leaves: Identify sand post oaks with their deeply lobed, rounded leaves that have rounded tip.
The Oregon white oak is native to the northwest coast of North America and grows between 65 and 100 ft. (20 – 30 m). Some types or Oregon oaks can grow as shrubs in small garden landscapes where they grow to between 10 and 16 ft. (3 to 5 m) tall.
Oak tree bark: Oregon white oak tree has bark that is lightly gray, heavily furrowed with pronounced ridges.
Oak tree leaves: Oregon white oak tree has glossy green lobed leaves with rounded tips. The leaves have “U” shaped sinuses and a slightly rounded apex.
Sessile Oak bark, leaves and acorns
The sessile oak is large species of white oak that grows to between 66 and 130 ft. (20 – 40 m) tall. Native to Europe, the sessile oak is widespread in Ireland and is also called the Irish oak. The deciduous oak’s leaves turn from dark olive green to golden yellow in the fall.
Oak tree bark: The sessile oak tree has smooth gray bark when young that gradually becomes fissured as it matures.
Oak tree leaves: Identify the sessile oak tree by its sinuated leaves that are slightly lobed and look like teeth around the margins.
Chestnut oak trees are medium-sized white oak trees that grow to between 60 and 70 ft. (18 – 22 m) tall. Most of the foliage and branches grow at the top of the chestnut oak, where it has a spreading crown of up to 70 ft. (18 m) wide.
Oak tree bark: The chestnut oak is identified by its unique bark that has deep fissures producing pronounced peaked ridges.
Oak tree leaves: Chestnut oak leaves grow in clusters with bristle tooth edges and no lobbing. Pronounced veins in V-shapes also help identify the chestnut oak leaves.
Holm oak tree and its leaves
Holm oak tree is an evergreen species of white oak tree that also has names such as evergreen oak and holly oak. Holm oaks are a medium to a large-sized variety of oak tree that grows to 70 to 91 ft. (21 – 28 m).
Oak tree bark: Unlike other types of oak tree, the Holm oak has gray to black bark with fine fissures that look more like small cracks on the tree, similar to parched ground.
Oak tree leaves: The holm oak is identified by its glossy leaves that are oblong to lanceolate shaped without any lobes.
Chinkapin oak tree bark and leaves
The chinkapin oak is a large white oak tree that grows to between 45 and 110 ft. (20 – 33 m). This oak tree has branches that emerge from the trunk reasonably close to the ground. The leaf growth is similar to the chestnut oak tree; however, the chinkapin oak has pointed, not rounded teeth, on its blade margins.
From all of the white oak tree species, the chinkapin tree has the sweetest acorns.
Oak tree bark: Identify the chinkapin oak tree by its flaky gray bark and shallow fissures.
Oak tree leaves: Chinkapin oak tree has leaves that look like chestnut leaves, only with sharper, pointed teeth without any bristles.
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