In addition to leaves and flowers, you can look a tree's bark characteristics.

If you are identifying a tree, you probably look at its leaves before anything else, or the tree's flowers or fruit if it has that. But don't forget about the tree's bark. At first glance, this protective outer coating of a tree's trunk and branches may seem like an unending sea of gray and brown. However, when you look more closely, you'll see variations in the colors and textures.

Here are eight identifying tree bark characteristics you'll want to keep in mind.

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Smooth, Unbroken Bark

Young trees sometimes have smooth bark that's unbroken by ridges. Often this will change as trees age, according to Michael Wojtech who wrote the book, Bark: A Field Guide to Trees of the Northeast.

But a few species, like the American beech and the red maple, keep their smooth, unbroken bark throughout their lifespans.

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Peeling Bark

You have probably noticed peeling trees before. Does this mean they're dying?

Not quite—Wojtech explained that the trees' wood is growing faster than the bark surrounding it, so the tree itself pushes outward against the bark. On some species, the pressure causes thin layers of the protective outer cork layer to separate and peel away. This is common to sycamore, birch, and maple trees, to name a few species.1 In the paper birch trees, in particular, the layers peel away in horizontal, curly strips.

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Lenticels

Lenticels are pores that move carbon dioxide and oxygen through a tree's protective outer bark. All trees have them, but they're more visible on some species than others, according to Iowa State University Extension and Outreach.2

Lenticels come in many different shapes, sizes, and even colors. Wojtech has identified that yellow birch trees have dark, horizontal lines, while young bigtooth aspens do not have lines at all but instead diamond-shaped lenticels.3

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Deep Ridges and Furrows

If a tree has a very rough bark, take a look at its ridges and furrows. These are actually gaps in the bark's outer layers, called the rhytidome.

Some species, like white ash, can have ridges and furrows that intersect. Others, like the Northern red oak, have uninterrupted ridges, while the white oak has ridges that are broken horizontally.

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Scales and Plates

Instead of ridges, some trees have breaks in the rhytidome layers that look more like plates or scales. Many pine and spruce trees have scales of bark, while species like the black birch have thick, irregular plates on their trunks.

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Color

In addition to the texture of a tree's bark, you can also pay close attention to the color and shade of a tree in order to identify it. Once you start looking, you'll find there's a lot more than just plain brown. Beech trees have a light gray bark, while black cherry trees have a dark red-brown. Black walnut trees have dark gray to black bark, and oak trees have a light gray bark.4

It can be difficult to keep track of the various colors, but sometimes the name of the tree will give you a hint.

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Unusual Characteristics

Thorns on a honey locust tree.

Some trees are extra unique. Aside from ridges, lenticels, color, and peeling layers, some tree species grow additional parts that are very distinctive.

On wild varieties of the honey locust tree, you can find large, red thorns on the trunk and branches. The thorns usually have three points, but can have many more, especially on the trunk.5 They look like spines and can grow to be three inches long. Similarly, the Hercules club—also known as the toothache tree—grows wart-like tubercles on its bark.6

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Smell Test

That's right—one more way to ID your tree is by taking a whiff of its bark.

While not all trees will have a distinct odor, some do. According to the National Park Service, the Ponderosa pine smells sweet, like butterscotch or vanilla. Similarly, The Master Gardners of Northern Virginia states that other pine trees smell like turpentine, while yellow birch smells like wintergreen, and sassafras trees can smell like cinnamon and spice.7