Oak trees are beautiful, strong and stately…but in danger.
Under the IUCN Red List criteria, 32 species of oaks are critically endangered, 57 species are endangered, and 23 are vulnerable to extinction.1
But, it doesn’t have to be that way. By learning about these 7 types of Oak trees, their leaves and colors, and other beauties, as well as how to care for and plant them, you can help this majestic tree continue to tower above the threat in the forests around the world.
- Family: Beech Fagaceae
- Genus: Quercus
- Leaf: Lobed, toothed
- Bark: Thick, gray, with deep vertical furrows
- Seed: Acorn
- Blossoms: The male blooms grow as tassels. The female blooms grow on the husks and where the acorn develops
- Fruit: Acorn
- Native Habitat: Cold temperate to tropical latitudes in the Americas, Europe, Asia, and North Africa
- Height: 30-50 feet. Some grow to 80 feet
- Lifespan: 150-300 years. Some oaks live in excess of 500 years
- Canopy: Leathery, dark green leaves
- Type: Deciduous
IUCN Red List of Threatened Species Ranking
Oak trees have ruled the forests for millennia and are long associated with strength, wisdom, resistance, and morality.
The Power of Oak Trees
Did you know that the oak tree’s heritage goes back to 66-100 million years!
But…the word “oak” has no definite origin. It is present in Old English that evolved from Proto-German. The significance of the oak tree is exemplified in Indo-European languages when it was sometimes used as a reference to all trees in general.
This comprehensive guide tells you everything you need to know about oak trees… including how to care for them so they can continue to flourish.
Types and Varieties of Oak Trees (Oak Tree Identification)
There are hundreds of oak tree varieties… hundreds.
The United States alone has ninety types of oak trees that grow from coast to coast. And while most are separated into black, red, and white oaks, there are quite a few others that grace not only North America but countries around the world.
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Here are some of the most common species:
1. Black Oak
Native Region: Eastern and Central North America
A small oak with a wide and open crown, its leaves are shiny and green on top and lower and of a lighter hue on the bottom. But, Black Oak trees actually have leaves that can vary from tree to tree… even branch to branch, so identifying this tree can be a little tricky. The leaves themselves are thicker and tougher than a Red Oak leaf, and they have a shinier top surface of deep green.
The buds on the end of the leaves are hairy, not smooth and rounded, and in the fall, the leave change to a dull red or orange-ish color.
This variety is also sometimes known as a “yellow oak” because the yellow pigment is found in its inner bark.
Interesting Black Oak Facts: The Cherokee used this tree to make tea to treat asthma, but the wood itself is only considered useful for some furniture and home building qualities.
2. Northern Red Oak Tree
Native Region: Midwest region of the U.S.
This oak tree’s leaves have wide lobes, and it can grow to become one of the largest of the trees, with some reaching over 100 feet in height. The leaf’s bristles are tipped and they turn red come fall (thus the name).
They prefer moist and well-drained soil and tolerate full sun or partially shaded environments, and these trees are highly resistant to many diseases and decay, including the rare ability to tolerate black walnut toxicity.6
Interesting Northern Red Oak Facts: Because of the way the wood can withstand the elements, it was used for shingles by pioneers. And, this tree can grow up to a full 12 inches in one year.
3. White Oak Tree
Region: Grows in the eastern and central parts of the United States, including the lower elevations of the Smoky Mountains.
White Oak tree leaves have usually around nine rounded lobes and are more delicate than the other rounded-lobe leaf oak, the Post Oak. Its bark color is a shade of light gray but changes when it’s harvested as lumber.
White oaks are GIANTS! They can grow up to a hundred feet tall! and can live as long as 450 years… or longer. In fact, some of the world’s oldest can live up to 450 years.
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The white oak grows in various climates but prefers lowland areas. It does well growing in the Appalachian Mountains. The tree’s lumber is in high demand in the construction of wine barrels, percussion instruments, and even banjos.
Interesting White oak Tree Facts: Mountain dwellers used white oak strips to make baskets and weave chair seats, and in the fall the leaves change to both yellow and red.
Named for its vibrant fall color, the acorns it produces are favorites of squirrels and Blue Jays.
4. Scarlet Oak
Regions: North America and Europe, usually flourishing in lower elevations.
The Scarlet Oak leaves are glossy and shiny on both top and bottom with a distinctive “c” shape situated between the lobes, and the lobes themselves are pointed.
Interesting Scarlet Oak Fact: The tree grows remarkably fast and yields up rich scarlet colors in the fall.
5. Southern Red Oak
Regions: Lower elevations in North America
Unlike the Northern red Oak, the Southern variety features leaves that have usually five lobes, with the long center lobe often called a “finger.” The undersides of the leaves aren’t glossy like the top but are covered in fine hairs that feel felt.
The cap of the acorn is also unique, being very small like a tiny little hat.
Interesting Southern Red Oak Facts: This oak tree turns greenish-yellow to orange in the fall and features dense, heavy wood.
6. Post Oak
Regions: Prefers drier conditions and lower elevations
The Post Oak has an unusual leaf shape, with square-like lobes on glossy-topped leaves. With the largest lobe in the middle, the underside of the leaves has velvety hairs and the gaps between the lobes are rounded, not coming into the traditional point.
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Deer, turkeys, raccoons, and squirrels love these acorns, which feature a cap that covers about one-third of the surface.
Interesting Post Oak Fact: The Post Oak got its name from the fact that the wood was often used to make fence posts.
7. Chestnut Oak
Regions: Prefers dry, rocky areas under 4000 feet in elevation
The leaves of the Chestnut Oak don’t really resemble an oak very much, but they are thick and leathery, allowing the tree to withstand dry, sunny areas. The leaves themselves are oval in shape, with indentions that resemble serrated edges.
The acorn features a large cap, that covers about half of the surface and has bumpy knobs on it. It turns a bright crimson color (or yellow) in the fall.
Interesting Chestnut Oak Tree Facts: This species of hardwood has largely replaced the American Chestnut tree (after the blight) and the Cherokee used the tannin from the bark to tan hides.
Habitat Growing Needs: How To Care for Oak Trees
Like all tree species, oak trees need certain conditions to thrive and flourish. Before planting an oak seedling, make sure to have the room available so that the tree can mature to its full glory.
- Soil Conditions: Oak trees prefer moist and well-drained soil. Soil with 6-7 Ph is best. Fertile and deep soil is preferable but oaks can also do well planted in average soil. Sandy and clay-based soil are not recommended.
- Water & Sunlight: Oak trees enjoy sunny or partially shaded environments. Their water needs are moderate and they can survive moderate drought. They shouldn’t be planted in very dry soil or soil that is regularly water-saturated.
- Maintenance: Oak trees need little maintenance. Newly planted trees require watering. Mature oaks don’t require irrigation unless facing a serious drought. Fertilizer isn’t required. Pruning takes place in the summer and involves the removal of dead and broken branches.
- Variety Considerations: Certain oak trees like the water and willow oaks grow best in swampy conditions. Oak varieties have different root structures, some of which reach deeper into the ground and can store moisture for leaner times.
It’s important to allow the oak tree plenty of room to grow. It’s advised to plan for a space of eighty feet wide and eighty feet tall.
Oak trees can be massive. Some reach the height of seventy feet and spread 135 feet with a nine-foot wide trunk. These huge trees consume fifty gallons of water daily, which is why they’re good urban trees in their ability to soak rainwater runoff and prevent erosion damage.
How To Identify Oak Tree (From Pin Oak Tree to Live Oak Tree)
Because there are a number of varieties of oak, they can be tricky to identify at first glance. You can identify types of oak trees by leaf or bark, but there are also many resources that list types of Oak trees in Florida, types of Oak trees in California, or types of Oak trees around the world. Fortunately, there are some common characteristics that are easy to spot.
Oak Tree Leaves (Oak Tree Leaf Identification Chart)
If you’re looking for an oak tree leaf identification chart, there are many available. Most oak trees are recognized by distinctive lobed leaves. White oak leaves have rounded tips. Red oak leaves support pointed tips.
White oak leaves have rounded lobes and tips with the lobe tip missing the bristles. Some have rounded serrations along the leaves’ edge.
Red oak trees support bristles on their pointed-lobed leaves. Red oaks have a greater variety of shapes in their leaves. Some are smooth while others are jagged. Water oak leaves vary in shape from rounded oval to three-lobed bristle tipped.
And, willow oak leaves look entirely different!
Oak Tree Acorn
The acorn is the nut of oak trees. It holds one seed that’s held in a tough shell. Acorns are as small as half an inch and as large as two inches.
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Raw acorns shouldn’t be consumed because they contain tannins—a toxic substance when eaten in large quantities. The tannins can be removed by boiling or soaking the acorn and when the fruit is edible and chock full of iron and manganese. Acorns can also be ground into flour.
Oak trees don’t produce acorns until they’re twenty years old. One oak can produce 2,000 acorns annually. Only about one in ten thousand will root and grow to be a new tree.
How to Plant an Oak Tree?
The acorns of white oak and swamp white oak are planted in autumn. They germinate soon after sowing. Acorns of bur oak, pin oak, and red oak won’t germinate until they’re exposed to cool and moist weather for a few weeks.
Squirrels love to bury acorns, helping to replant the forest.
Oak Tree Bark
The bark of sapling oak is smooth and silver-brown. The bark grows fissured and develops ridges and grooves as the tree matures.
Depending on the oak’s variety, the bark turns light gray in white oak and almost black in red oaks.
Oak Tree Flowers
Both male and female flowers grow on the same oak tree. Male flowers bloom on catkins and hang low while female flowers are red, small, and grow on short stalks.
The male flowers release pollen in April and May and the female flowers become acorns by fall.
Oak Tree Fruit
White oak acorns ripen quicker than red. Namely, the acorns of white oaks take one full season, and red takes twice as long.
Red oak acorns are larger and heavier than white oak acorns.
White oak acorns taste sweet or slightly bitter. Acorns from the red oak tree are bitter and not worthy of eating.
Medicinal Qualities of Oak Trees
Oak bark (Quercus alba) usually comes from white oaks native to North America. It’s derived from the inner bark and round growth that form on the tree.
Oak bark is dried and ground into a powder for topical and oral use. It’s been effective for medicinal use for millennia.
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Other medical applications suppress inflammation and soothe itchy skin. Oak bark tea helps treat diarrhea, common colds, sore throats,7 as well as bronchitis, loss of appetite, and arthritis.
Oak bark is sold as a powder, tea, pill, or liquid extract, and is sold without prescription in the U.S.
Benefits and Uses of Oak Tree Bark
Oak tree bark has been used for centuries by Native Americans and others for it’s beneficial uses.
- Skin Irritation
Oak bark contains 20 percent tannins that act as astringents that bind to proteins in the skin to tighten pores and dry out irritated skin (which is also used for tanning hides). Hemorrhoids8 are treated by bathing in water mixed with oak bark powder to dry out sores.
Oak bark is effective as an astringent and antibacterial ointment for wounds, irritated gums, and teeth. It can be gargled, swallowed, or applied to the skin.
Thus, more extensive research is needed to understand the safety and effectiveness of oak bark.
Although using oak bark to treat certain skin conditions is popular in some holistic medicine, there is little proof to back up this claim. It’s been noted that oak bark can sometimes aggravate irritation when applied to cracked skin.
- Antioxidant Activity
Oak bark compounds may act as antioxidants9 that protect our bodies from damage caused by reactive molecules called free radicals. The antioxidant activity is thought to assist heart and liver health.
More extensive research is needed to understand the safety of the long-term use of oak bark products.3
Strange Oak Tree Facts, Folklore, and Religious Significance
Oak trees are part of many mythologies and religions worldwide. In Nordic mythology, the oak tree is the sacred tree of Thor, the god of thunder. The Greeks considered the oak a sacred tree of Zeus. It’s an important tree to Perun, the Slavic god. The Bible mentions the oak tree in the ancient city of Shechem.
- Oaks and Robin Hood – An oak tree (named Major Oak), near Edwinstowe, a village in Sherwood Forest in England, is presumed to be 1,000 years old and was supposedly alive when Robin Hood and his men hid from the sheriff.
- America’s national tree – Oak trees were declared America’s national tree in 2004. They symbolize the nation’s strength and steadfastness. The oak is also honored by several European nations.
- Oaks in the armed forces – Oak leaves are part of the design of ranks of the U.S. Army. A silver oak leaf honors a Lieutenant Colonel or a Commander. A gold oak leaf honors a Lieutenant Commander or Major.
- The oak is the sacred tree of Zeus, and the centerpiece of Dodona, the Hellenic oracle. In 500 B.C., worship ceremonies were performed under oak trees, and when priests offered divine solutions and interpretations.
- Oak trees are more prone to be struck by lightning than other trees. Perhaps that’s why the oak is the symbol of Thor, the god of thunder and lightning? Aside from their spiritual nature, oaks were considered practical when the Vikings built their boats and ships.
- The oak is sacred for Native Americans, whose chiefs drew courage and sought guidance beneath its wide canopy and a sturdy trunk within which the Great Spirit dwelled.
- Beliefs concerning the oak tree were also found in Christianity. Abraham’s Oak marks where he pitched his tent. The fable says that anyone who disrespected the tree would claim their firstborn child.
- Symbolizing strength, stability, and power, the oak tree was worshiped in many cultures and regarded as the representation of gods. The oak’s ability to withstand stormy weather earned it the names Mighty Oak and King of Trees.4
How Much Carbon Does an Oak Tree Sequester?
A 50-year-old oak forest would sequester 30,000 pounds of carbon dioxide per acre.5 The forest would emit 22,000 pounds of oxygen.
Two oak tree varieties, post oak, and live oak, widely populate the U.S. South and remove black carbon from the urban atmosphere, proving that protecting the oak tree is crucial to the planet’s survival.
Frequently Asked Questions About Oak Trees
What Is So Special About Oak Trees?
Oak trees represent many things to many cultures, but as the United States’ national tree, the oak represents longevity… in fact, one tree in England is supposedly over 1000 years old!
How Do I Identify an Oak Tree?
One great way to identify oak trees is by their fruit (acorn), but you can also check out their leaves, which feature ‘lobes’ on the tips.
How Long Does It Take for an Oak Tree to Grow?
An oak tree takes many years to grow and can live for hundreds of years.
Where Do Oak Trees Grow Best?
Depending on what type of oak tree, they grow best in moderate climates.
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1Oldfield, S., & Eastwood, A. (2007). The Red List of Oaks. Red List. Retrieved July 19, 2022, from <https://www.iucnredlist.org/resources/eastwood-and-oldfield-2007>
2Tree Guide Uk. (2022). Tree and Flower Identification Guide. Trees and flowers – Tree Guide UK. Retrieved July 19, 2022, from <https://www.treeguideuk.co.uk/>
3Healthline Media. (2020, June 4). Oak Bark: Benefits, Dosage, Side Effects, and More. Healthline. Retrieved July 19, 2022, from <https://www.healthline.com/nutrition/oak-bark>
4Jay, N. (2022). What Is the Symbolism of Oak Tree – History and Meaning. Symbol Sage. Retrieved July 19, 2022, from <https://symbolsage.com/oak-tree-symbolism-and-meaning/>
5Scott, T. (2022). Carbon Sequestration in Oak Woodlands. University of California. Retrieved July 19, 2022, from <https://ucanr.edu/sites/forestry/files/211097.pdf>
6The Morton Arboretum. (2022). Northern red oak. The Morton Arboretum. Retrieved July 19, 2022, from <https://mortonarb.org/plant-and-protect/trees-and-plants/northern-red-oak/>
7Healthline Media. (2022). Help for Sore Throats. Healthline. Retrieved July 19, 2022, from <https://www.healthline.com/health/cold-flu/help-sore-throats>
8Healthline Media. (2021, November 8). Causes of Hemorrhoids and Tips for Prevention. Healthline. Retrieved July 19, 2022, from <https://www.healthline.com/health/hemorrhoids#5-Home-Remedies-for-Hemorrhoids>
9Healthline Media. (2022). Antioxidants Explained in Simple Terms. Healthline. Retrieved July 19, 2022, from <https://www.healthline.com/nutrition/antioxidants-explained>