Oak trees (Quercus genus) are a large family of over 600 trees that come in various shapes and sizes. There are even some conifers, or evergreen trees, in the mix! Oaks are native to many environments. They are the tree of choice for numerous nesting animals, such as birds and squirrels. They also produce copious amounts of acorns, directly supporting the food chain.
Oat trees are a popular street tree to plant, especially in Portland. They are also commonly found in parks, golf courses, and college campuses. They offer interest branches and offer large canopies. Their branches provide ample shade below, and when planted strategically, it can reduce the amount of electricity a homeowner needs to cool their house! They grow slowly, however, and are a long-term investment. To help you choose the right oak tree for your yard or landscaping project, we've discussed some of the species of oak below!
9 Types Of Oak Trees
All oak trees are part of one of two main categories- the white oak group or the red oak group. Each of these groups consists of hundreds of oak species. Don't confuse these groups for the individual oak varieties that share the same name! Yes, there are red oaks and white oaks, but they are just one of many of the species within each group. White oak trees have leaves with rounded lobes, and their acorns will sprout as soon as they fall to the ground. Some popular white oak tree varieties are swamp oak, bur oak, English oak, chestnut oak, gambel oak, water oak, and post oak.
Quercus Alba (White Oak)
White oaks grow slowly, but a mature white oak is simply majestic and boasts a canopy as wide as the tree is tall. A tree 50 to 80 feet high with a canopy 50 to 80 feet wide is a sight to behold! White oak leaves will have seven rounded lobes on each leaf and turn a deep crimson color in the fall. This is unique - oaks aren't known for their fall color. Acorns from the white oak tree are about an inch long, grown individually or in pairs. The cap covers about a quarter of the total acorn. White oaks need full sun and moist, acidic soil. Even if planted in perfect conditions, they grow slowly. But they're worth it!
Quercus Bicolor (Swamp Oak)
Swamp oaks thrive in the high moisture soils that give the tree its name. They are a bit shorter than the white oak, topping out at 60 feet, but their branches are just as large and spreading. Swamp oak branches, however, have a different growth pattern. The branches will often sprout a large number of secondary branches, and these secondary branches will sometimes curve back towards the ground, forming a large arch. The separation between the rounded lobes of the swamp oak is very shallow.
Quercus Robur (English Oak)
English oaks aren't native to the United States, hailing instead from Europe and western Asia. The tree itself looks very similar to the white oak, but the acorns are unique. English oaks have elongated acorns, and the cap covers a solid third of the acorn. The shape of the mature tree is also different, with the tree branching out from the lower portion of the trunk even at maturity. This makes the trunk look short and gives the tree a broad and rounded appearance.
Trees in the red oak grouping will have sharply pointed lobes on their leaves, and their lobes are sometimes tipped with tiny bristles. Their acorns mature after two years, and fallen acorns will sprout the following spring. Some popular red oak tree varieties are black oak, pin oak, scarlet oak, laurel oak, willow oak, and Spanish oak.
Quercus Rubra (Red Oak)
Red oaks are a mainstay in many regions of the United States, growing abundantly in woodlands. Their leaves have seven to eleven points. Red oaks stand apart from most oaks in that they have a relatively fast growth rate, making them favorites with many landscapers. They need an acidic soil with medium moisture and full sun to reach their mature height of 50 to 75 feet with a canopy width to match.
Quercus Velutina (Black Oak)
Black oaks look extremely similar to red oaks. Black oaks are slightly smaller, topping out at 60 feet, and can tolerate drier soil conditions. They have signature pointed leaves, but black oak leaves are usually darker and glossier than red oak. Their acorns are easier to tell apart - both red and black oaks have acorns about 3/4" in length, whereas red oak acorn caps only cover about a quarter of the acorn, black oak acorn caps cover at least half of the acorn! Black oaks also have distinguishing black bark at full maturity, with deep ridges and fissures.
Quercus Palustris (Pin Oak)
Pin oak trees are more often found in urban conditions than woodlands because they have a high tolerance for pollution and poor soil. You'll see them lining streets or in parks and college campuses. Pin oaks have an interesting branch habit. Their upper branches grow in a steep upward direction, their mid-tier branches grow out at a 90-degree angle from the trunk, and their lower branches droop downward and often lose their leaves. Their leaves tend to mimic this shape, with the middle lobes pointing more straight out than other oak leaves. Their acorns are small and pointy - hence the name!
Quercus Phellos (Willow Oak)
Willow oaks may be part of the oak family, but it's no surprise where it got the "willow" part of its name. Willow oak leaves really bear no resemblance to other oaks. They are also fast-growing trees and are narrower at maturity than other oak trees. Where most oak trees are as wide as they are tall, willow oaks are only about half as wide.
Quercus Coccinea (Scarlet Oak)
This type of variety offers deep and vibrant red fall color, and it is one of the red maple rivals in autumn time. During the summer months, scarlet oaks are even more appealing with their rich glossy green color. Each leaf has seven to nine lobes, and each lobe has a bristly tip.
Quercus Virginiana (Live Oak)
Live oak is a popular tree due to its massive and wide spreadings that offer a large amount of shade. This evergreen oak tree is often grown in warmer regions like the Southeastern United States.
Unlike the other oaks, this type of oak offers unique leaves that are elongated oval that are about one to three inches long.
Inaccuracy of common names
There are a few plants with "oak" in their common name, but they are not exclusive to the Quercus genus or the beech family. Oaks like silver oak, stone oak, and sheoak are not true oaks.