There are more than sixty species of oak in the US alone and more than hundreds of others worldwide. Identifying oak leaves is a challenge in itself. To assist in narrowing the identification process down to a specific tree, oaks can be divided into two basic categories based on leaf shape alone: red oak and white oak. The first step to identifying oak leaves is to learn the difference.
Step
Method 1 of 2: Studying Oak Leaves Effectively
Step 1. Distinguish the oak tree from other species
Oak, of which all species fall under the genus Quercus, is a plant widely distributed in temperate climates around the world. There are 600 known species of oak, 55 of which are found in the continental United States. Because there are so many varieties of oak trees in the world, it is quite difficult to find a characteristic that would unite them all. Nonetheless, such characteristics do exist:
- Acorn is the easiest way to show an oak tree. If a tree produces an acorn, it is certain that it is an oak tree.
- Leaf lobe i.e. leaves that have rounded or tapered strands, which extend from their midline. Although some oaks do not have lobes, all of their leaves are usually symmetrical around a well-defined median line.
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The bark of the tree is small and scaly.
There are various types of oak bark, which are generally made up of small, hard, scaly flakes of bark. Oak bark is different from pine bark, which is large and multi-layered, or birch bark, which resembles wallpaper. Oak bark looks more cracked and fluted.
Step 2. Look at the tips of the lobes to determine if the tree is red oak or white oak
The lobe is the part of the leaf that extends outward from the center of the leaf, like the five points on the tip of a star. White oak has rounded lobes, while red oak has tapered lobes. This important difference will reduce the potential number of trees you are trying to identify by half.
In red oak, the leaf veins extend outward to the leaf margins, forming a pointed tip
Step 3. Consider your geographic location
Each region has its own diversity of oak species that are often very different from the rest. The species of oak you encounter will vary greatly depending on where you are in the world. Certain oaks on the east coast would be very rare on the west coast, as well as southern oaks would be hard to find in the north. Usually you can specify a region by a number of criteria (the example here is for the continental US):
- Common locations -- Northeast, Southeast, Midwest, Northwest, Southwest
- Inland or coastal.
- Mountains or flat areas.
Step 4. Count the number of lobes per leaf
The lobe is the part of the leaf that extends outward from the center of the leaf stem to both sides. If possible, compare several leaves to find the average number of lobes. Some species, such as the willow oak, have no lobes at all, but most oaks have multiple.
Count at least 4-5 leaves when doing identification, it will help you when opening the field guide
Step 5. Measure the curve between the leaves
Look at the area between the lobes and determine if the indentation is deep or shallow. White oak leaves often have a variety of indentations that vary randomly between shallow and deep, while red oak has sharp or no indentations.
Step 6. Notice the change in color in the fall
The evergreen oak leaves are characterized by a dark green color and are glossy all year round. However, most oaks will change color in the fall. Some oaks, such as scarlet oak (Quercus coccinea), display vibrant colors in fall. White oak and chestnut oak are often dull brown when leaf color has returned.
To help determine the species, see if the leaves are dark green or light green in color, and whether or not they are glossy in the summer
Step 7. Measure the leaf as a whole
Green malar oak leaves and a small number of red oaks such as bush oak have smaller foliage, whereas most red oaks and almost all white oaks have much larger leaves (at least 10 cm). It is this factor that is more important as a distinguishing feature between the various species of similar oaks.
Step 8. Identify unknown oaks using the US Forest Service's Field Guide
Based on the data that has been collected, identify the oak tree using the tree manual or field guide. There are tons of oaks out there, and you can't just hope to figure them all out. Use the criteria above to narrow your selection, then use the field guides to find the type of oak you're looking for. You can look through the collection of common oaks below, or in the Field Guide obtained from the US Forest Service.
- Open the appropriate section. Most of the guides are divided into a red oak section and a white oak section
- Narrow the selection to oaks that are specific to your area. A good guide should have a map of the distribution of each species.
- Once you have a list of possibilities, look at each image to determine which oak tree you want.
Method 2 of 2: Recognizing Some Common Oaks
Ordinary White Oak
Step 1. Identify the common white oak based on the scaly and warty acorns
The category for white oak is not just one for all types of white oak, there is actually a White Oak (Quercus alba). This white oak is distinguished by the wart-like markings and scales on the acorns and the brightly colored bark of the tree. White oak foliage has:
- 5-7 lobes, the closer the tip of the leaf will be wider.
- The indentation is approximately half the width of the leaf.
- The color of the leaves is bright and young.
Step 2. Identify Ek Post. This US Midwestern region oak has a dark bark and distinctive leaves:
- Usually has 5 lobes.
- The lobes are wide and shaped like a cross.
- The texture of the leaves is rough and the color is dark.
Step 3. Identify Bur Oak
Bur oak also found in Central West America has large leaves and special seeds, with large cups (small caps at the base of the acorn) that cover almost the entirety of the acorn.
- The length of the leaves can reach 30 cm.
- The lobe of the leaf is wide and the tip is almost flat.
Step 4. Identify the Chestnut Oak
This one oak is often found on rocky land. This oak tree is widespread and has reddish-brown acorns and wrinkled dark brown bark.
- The leaf margins look like serrated blades and the leaf veins do not reach these points.
- The leaves are broad at the top and narrow downwards.
- The size of the leaves is about 10-20 cm long and 10 cm wide.
Ordinary Red Oak
Step 1. Identify the Common Red Oak
Common red oak has acorns that have a flat top, as if they were wearing a pork pie hat.
- The leaves are light green with 6-7 lobes.
- The indentation of the leaves is up to half the width of the side of the leaf.
- The lobes are tapered with the possibility of having two smaller ends on one side.
Step 2. Identify the Shumard Oak
The cup of Shumard acorns is shaped like an egg and covers only 1/4 of the acorn. The bark of the tree is long and brightly colored. Its height can reach 30 meters.
- The leaves are dark green.
- The base of the lobe splits into many hairy ends.
- The indent is deep.
Step 3. Identify the Oak Pin
Oak which is usually used as an ornamental tree can grow quickly. The seeds are small and look different and have a saucer-shaped cup. The bark of the oak tree is gray and smooth.
- The leaves are thin with deep grooves so they look thin.
- Has 5-7 lobes with many ends.
- During the fall the colors are very bright and striking.
- Northern US Pin oak has smaller leaves, but longer acorns.
Step 4. Identify the Black Oak
Black oak has ordinary leaves, but there is a layer under the bark that is bright orange. Often you can see cracks in the black oak tree.
- The leaves are dark green.
- The size of the large leaves up to 30 cm long with the tip of the leaf wider than the base.
