Oak Tree

The oak tree, named America’s National Tree, is part of the Quercus genus and the Fagaceae family. Oak trees can be found in a variety of climates across North America, Europe, Asia, and Central America. They are a popular choice for parks and neighborhood streets because they provide great shade, change to gorgeous colors in the fall, and are a beautiful addition to any landscape.

Some oak tree species are deciduous, some are evergreen, and some are considered to be semi-evergreen. Deciduous means trees shed their leaves for an extended period of time whereas evergreens are never without leaves. Semi-evergreen can mean a variety of things including that those species may lose their leaves for a shorter period of time than most or it can mean that the tree could shed some, but not all of its foliage at some point during the year.

The two main oak species found in North America are the white oak and the red oak and they often have very different identifying features.

How to Identify an Oak Tree

  • LEAVES

    Oak tree leaves have symmetrical rounded or pointed lobes, depending on the species, around a central line.

    For example, a white oak has rounded lobes and a red oak has pointed lobes. Some species, such as the willow oak have no leaf lobes at all, but most have several lobes that alternate with cutouts, called sinuses, that vary in depth. Oak leaves grow out of a branch from all directions, meaning that there is no parallel or straight formation.

  • BARK

    The bark of oak trees can vary, but it is generally scaly, gray, small, and hard.

    Oak tree bark has deep grooves that give a bumpy texture to the bark. White oak trees have lighter bark whereas red oaks have darker bark.

  • SHAPE AND GROWTH

    Oaks are known for their immense size as they can grow to be 100 feet tall. They typically have a full, rounded shape and can be just as wide as they are tall.

  • TRUNK AND ROOTS

    The trunks of oak trees are very thick, sometimes even reaching 30 feet. A contributor to this is how long oak trees can live, as over time a tree’s trunk gets wider and wider. Oak trees can live for hundreds of years.

  • ACORNS

    Oak trees are the only trees that produce acorns. The seeds of the oak tree are located inside of its acorns, which typically hold one seed each. Acorns are brown and cup-like in shape, a structure known as a cupule, with what looks like a woody cap on top. Different species have acorns of many different sizes and shapes. White oaks produce acorns that are more gray in color and red oaks have acorns that are red to brown. A planted acorn in the right environment can begin to sprout an oak tree in six to 18 months.

Various Oak Species

There are hundreds of oak tree species in existence today. Here are some of the more common oak species:

  • SCARLET OAK

    (Quercus coccinea) The scarlet oak is known for its striking red colors in the fall. It is a fast-growing tree that can reach heights of up to 80 feet and widths of around 40 or 50 feet. The inner bark of this species is even red as well.

  • NORTHERN RED OAK

    (Quercus rubra) This species of oak tree is tolerant to pollution and compacted soil, making it a great choice for urban streets and environments. The northern red oak is the state tree of New Jersey.

  • PIN OAK

    (Quercus palustris) The pin oak is a very popular choice for parks and yards because it provides great shade, is tolerant of various soil conditions, and it does not harbor many pests. It takes on more of a pyramid shape for most of its life.

  • WHITE OAK

    (Quercus alba) The white oak is a broad and rounded tree that grows to be 50 to 80 feet tall. It is the state tree of Connecticut, Maryland, and Illinois. Its growth rate is slow to medium. White oaks often turn a dull brown in the fall.

  • LIVE OAK

    (Quercus virginiana) This tree is commonly found in southern regions of the United States covered in Spanish moss. Live oaks can live for hundreds of years. They can also grow to be around 80 feet tall and they can be just as wide.

  • WILLOW OAK

    (Quercus phellos) Willow oak trees are often found in parks, along streets, and around golf courses because of the great shade they provide and their fast growth. It gets its name due to its leaves that have a willow-like appearance.

  • BUR OAK

    (Quercus macrocarpa) The bur oak tree can grow to be 80 feet tall and 80 feet wide, which makes it a good fit for parks and expansive landscapes rather than in smaller yards and spaces.

  • SAWTOOTH OAK

    (Quercus acutissima) Known for its rapid growth during its early stages, the sawtooth oak is adaptable to many growing conditions. This species usually tops out around 60 feet tall and takes on a beautiful shade of yellow in the fall.

  • CHINKAPIN OAK

    (Quercus muehlenbergii) Chinkapin oaks are a deciduous species of oak that can grow up to 60 feet tall. They do best in full sun and well-drained soils. It can take up to 30 years before acorns appear on this tree.

  • SHUMARD OAK

    (Quercus shumardii) Shumard oaks are extremely resilient to flooding, droughts, and high winds, which make them a good pick for homes in many climates. New shumard oaks can grow one to two feet each year and reach a mature height of 40 to 60 feet.

  • OVERCUP OAK

    (Quercus lyrata) This species of oak is known for its adaptability to different soil conditions, hardiness, and size. Overcup oaks are gaining in popularity with growers and home landscapers, due to its positive qualities and the fact that it transplants easily.

Creatures Found in and Around Oaks

Wildlife are drawn from far and wide to oak trees for the sturdy shelter and acorns they provide. Here are some of the creatures
that you can find in oak trees:

  • Wild Turkeys
  • Deer
  • Caterpillars
  • Quail
  • Squirrels
  • Rabbits
  • Ducks
  • Birds
  • Opossums
  • Foxes

Oak Decline

Wildlife are drawn from far and wide to oak trees for the sturdy shelter and delicious acorns that they provide. Here are some of the creatures that you can find in oak trees:

CAUSES

Harsh environmental conditions such as drought, climate changes, or age are often the precursor for oak decline. They leave the tree vulnerable to pests like armillaria root rot and the two-lined chestnut borer, which weaken the tree even further allowing oak decline to swoop in.

  • ARMILLARIA ROOT ROT

    A common fungal disease, armillaria root rot goes after an oak’s roots and trunk. One sign of the disease is the sprouting of brown mushrooms at the bottom of the tree, which usually appear in the fall.

  • TWO-LINED CHESTNUT BORER

    This insect is known for attacking weakened oak trees by burrowing into their vascular systems. To keep them at bay, make sure your tree is as strong and healthy as possible by keeping up proper watering, mulching, and drainage practices.

Identifying Oak Decline

To help identify whether your oak tree is experiencing oak decline, here are some common identifiers of the disease:

  • Thinning of leaves, starting at the top of the tree and spreading down

  • Dying branches and twigs

  • The development of epicormic sprouts

  • Premature fall coloring

Preventing and Managing Oak Decline:

In early stages of infection, start with pruning back all of the infected limbs.

Deep watering of a newly infected tree in the summertime can also help.

If the infection is too far gone, it is best to completely remove the infected tree.

Sanitizing tree trimming tools is essential to prevention. Pruning fresh limbs after pruning infected limbs can spread the disease by introducing the disease at the point of a freshly made wound.

Other Dangers to Oak Trees

Here are some other diseases that can damage oak trees and how to identify them.

  • OAK LEAF BLISTER

    Small bulges forming on leaves

    Browning and twisting leaves

  • ANTHRACNOSE

    Dots growing along margins or veins of leaves, then leaves fall.

  • HYPOXYLON CANKER

    Sunken in areas on bark

    Silver fungus under the bark

    Yellowing
    leaves

    Dying branches

  • OAK WILT

    Browning and wilting of leaves at top of the tree

    Dying branches

    Suckers sprouting on the trunk of the tree

Uses for Oak Wood

Since there are so many species of oak trees, the characteristics and uses of oak tree wood can differ significantly. For example, white oak wood is light brown in color and very durable. However, red oak wood is reddish brown and less resistant to rot and pests than white oak wood. Here are some uses of the wood from various species of oak trees:

  • Furniture
  • Cabinets
  • Flooring
  • Trim
  • Wine Corks
  • Barrels
  • Fencing
  • Veneer
  • Framing
  • Drums