A Look at the Different Types of Oak Trees

From an acorn to a robust, mighty tree, the oak is often used as a symbol of patience and durability. Oaks are well-known for their sturdy trunks, distinctive acorns, and lobed leaves, as well as their longevity. In this article, we’ll profile some of the different kinds of oak trees that can be found around Nashville.

With around 500 species of oak trees across the world, there are many native American oaks (about 90 species) that are easy to care for when planted in the right place. Not only are they graceful landscape trees — oak trees are also important pillars of stability in an ecosystem, providing food and habitat for wildlife as well as a range of ecosystem services that make a location comfortable for people and animals to live in. 

Every oak belongs to the genus Quercus, producing acorns that feed deer, squirrels, wild turkeys, ducks, and many other animals (and humans, too!). Their massive trunks and sprawling branches are where nesting birds and insects of all kinds make their homes. Oak trees come in a wide variety of species that are adapted to specific environmental conditions, while others are tolerant of different environments. These trees can usually be distinguished by their bark, the shape of their leaves, and the form of their acorns.

What Is the Most Common Oak Tree?

The most common type of oak tree is the white oak (Quercus alba) due to its tolerance of various types of weather and soils. White oaks can be found across eastern North America, from northern Florida up to Vermont, where the tree can grow in moist to dry soils of all kinds and in full sun or partial shade, preferring slightly acidic ground. This adaptability makes the tree able to grow in all sorts of areas, from rural to urban, allowing white oaks to establish in many locations.

White and Red Oak Species

Oak trees are grouped into two types: white and red. White oaks tend to be larger, with lighter-colored bark and rounded leaves. Red oaks, on the other hand, have darker bark and pointed, bristle-tipped lobes on their leaves. Comparing the leaf shapes of red and white oaks is the easiest way to set them apart! Red oaks also tend to be slightly smaller than whites, and their acorns, which usually take two years to grow, have bitter tannins in them so they last longer in the ground. The acorns of white oaks are sweeter, and since they aren’t bitter, they are usually eaten quickly by browsing animals. Interestingly, some oak specimens, particularly young ones, will hold onto their dead leaves over winter (like the beech tree, to which oaks are related, both being members of the Fagaceae family!).

Here, we’ll go over a few species from the white and red oak groups, including the white oak proper, the bur oak, and the swamp white oak. Some of the red oaks included are the red oak proper, the pin oak, and the Shumard oak.

White Oak

The white oak tree (Quercus alba) has the rounded, lobed leaves typical of white oak trees, with deep sinuses (spaces) between the lobes, which protrude like little fingers. Its preference for loamy, well-drained yet moist soil and slightly acidic pH makes it a great choice for large neighborhood yards, where it’s able to absorb lots of moisture (although it’s able to survive in somewhat drier soils as well). However, it’s a big tree, usually reaching up to 80 feet, with strong, lateral branches that spread straight out and create a massive crown, so it shouldn’t be planted too close to a house or power lines. 

White oak trees have flakey bark that gets flakier further up the trunk, which creates little protective crevices that bats like to roost in. The white oak’s bark is a light gray color, and its acorns have bumpy, often two-tiered caps. In the fall, the white oak’s leaves turn a purplish or reddish brown before they drop.

Bur Oak

The bur oak (Quercus macrocarpa) is one of our absolute favorite trees! This friendly oak is a true southeast native, and while slow-growing, it’s long-lived. A bur oak is a large shade tree that can grow up to 80 feet tall, with a somewhat rounded crown that is made of wavy branches and distinctly oakish leaves that have wide, rounded lobes. The leaves of a bur oak are shaped like a fiddle, with a wide, wavy top and very shallow sinuses and a thinner bottom half with short, well-defined lobes. The bark of a bur oak has deep gray or brown ridges that don’t flake or peel like a “regular” white oak (Q. alba). 

This is another great choice for large neighborhood yards since it has good resistance to flooding, drought, and pollution. This tree’s acorns have large, scaly, single-tiered caps that look like burs as they develop (but don’t worry, they aren’t prickly!). These seeds germinate quickly if they aren’t eaten first, being a favorite food for wildlife. Their dense foliage provides lots of habitat for birds, insects, and other animals, and the leaves turn to a dark yellow or bronze color in autumn.

Swamp White Oak

Swamp white oak (Quercus bicolor) is an oak that does particularly well in acidic soil (tolerating a pH between 5 to 7.4), growing naturally in bottomlands that don’t drain too well. This means it can tolerate wet to moist soil, which gives this tree its swampy common name. Otherwise, it’s similar to other white oaks in many ways! It’s a tall, shady tree that has leaves with rounded lobes and produces tasty acorns. The swamp oak’s acorns are quite large (about an inch on average) with a scaly cap. Its bark is somewhat darker than the white oak or bur oak, and it grows in ridges and peels over time. 

The leaf of a swamp oak is characteristic of this type of oak: its rounded lobes don’t have deep sinuses at all, giving a wavy shape to the otherwise wide and flat-looking leaf. Like the bur oak, it has a wider upper half than its thinner lower portion. Swamp oaks tend to have a pyramid shape until they reach full maturity, when they fill in. In fall, their leaves turn a deep orange-to-brown color. 

Red Oak

Red oaks (Quercus rubra) are, like other red oaks, slightly smaller than white oaks, tending to reach up to 70 feet at maturity. This doesn’t keep them from being great shade trees, though! Their bushy canopies grow lots of dense coverage. Their leaves are lobed, like other oaks, but they feature the defining pointed, bristle-tipped lobes of the red oak group. The interior leaves tend to have shallow, wavy lobes, with exterior and upper leaves having longer ones. 

The acorns of red oaks are medium-sized, usually about one-half to three-quarters of an inch, with shallow, scaly caps. The red oak group gets its name from the trees’ dark-colored bark, and red oaks proper tend to have light gray or white streaks between ridges in the upper parts of the tree (known as “ski tracks”). Their bark is tighter and doesn’t flake. In the fall, the leaves of a red oak tree turn to a dark red, purplish color.

Pin Oak

Pin oaks (Quercus palustris) are another wonderful oak tree for urban areas. They tolerate moist to wet sites and can survive in more acidic soils than some other oaks. A member of the red oak group, pin oaks have thin, pointed lobes with well-defined edges. The branches of this tree tend to droop at the bottom (don’t worry, though; they are strong!), with middle branches pointing straight out and upper branches angling toward the sky, giving it a distinct pyramid shape. Reaching up to about 70 feet high in maturity, it has a medium or dark brownish-gray bark color with thin ridges that flake off as it grows. 

Pin oaks have smaller, stout acorns, averaging about half an inch in length, with flat, smooth-scaled caps. The fall foliage of a pin oak is a coppery red or orange before it turns brown for the winter (and sometimes those dead, brown leaves hold on throughout the winter season, especially in young specimens!).

Shumard Oak

Also known as the swamp red oak, the Shumard oak (Quercus shumardii) is another oak tree that does just fine in moist or clay-heavy soils with higher pH levels (near 7.5), though it can also be grown in slightly alkaline, dryer soil. This makes it a great urban or neighborhood tree since it will tolerate the compacted, polluted, acidic soils that are found in built environments. Similarly, it's tolerant of air pollution, making it a good canopy tree to help filter the city air. These oaks grow straight and tall, up to 80 feet at maturity.

Their round crowns grow a dark green foliage that is great for shade. Shumard oaks have bristle-tipped, pointed, well-defined leaves that look similar to a pin oak, though the Shumard has wider lobes compared to the thin ones of a pin. You might even compare them to a holly leaf! The acorns of a Shumard oak are relatively large, about an inch long on average, with a bumpy cap. In the fall, a Shumard oak will turn to a golden or red color for the season.

A Diverse Genus

There are so many species and hybrids of oaks to be found that we can’t list them all! Rest assured, there is an oak tree type for every situation and location, given your property’s particular conditions and your own desires for an ornamental or functional tree. 

For more information on the different trees found around Nashville and how to care for them, subscribe to our newsletter! If you’re in the market for a new tree to plant, browse the wide selection available through our annual tree sale, open from October through February. If you don’t have any place to plant one yourself, consider volunteering with us to help us take care of Nashville’s city canopy!