Bark: nature's "tree-shirts."

Ranger Rick, April, 1998 by Deborah Churchman

Think of bark as armor for trees. It's that tough layer on the outside of the trunk and branches that keeps many insects and diseases o.u.t. Some trees have bark so thick that even fire doesn't get through it!

Check out the photos. See how different all these kinds of bark are? Some are smooth and tight (like copper-bark cherry). Others, such as the sycamore and ponderosa pine, are covered with puzzle-like pieces. Looks like those trees are wearing camouflage clothes, doesn't it? By the way, try sniffing ponderosa pine bark sometime. Mm-m-m, smells like vanilla!

Some really thin bark peels. Check out the curls on the paper birch. And doesn't Pacific madrone look as if it has a bad sunburn?

Bark can help you tell one tree from another. Some kinds of trees are even named for their bark, such as the alligator juniper. See that scaly-looking gator-like "tree skin"?

Balsam fir bark has "zits" that pop (try popping one--the resin inside smells like Christmas). Shagbark hickory has shaggy-raggy bark. The green parts of gumbo-limbo bark use sunlight to make food, just as leaves do. (The brown flakes you see are pieces of bark peeling off.) Cherry bark has tiny holes that work like nostrils! They let gases in and out of the tree. White oak looks all bumpy and wrinkled.

Tree bark--there's a lot to see, if you know what to look for. C'mon, try it!

Animals Use It...

BLENDING IN

Can you find the two calico butterflies in the photo at right? They're bark look-alikers. Their disguise helps them hide from birds and other hungry enemies. Many moths and other insects use the same trick.

Other little creatures hang out on bark. Check out the trees near you--do you see ants scurrying up and down the trunks? Maybe you'll find earwigs or spiders hiding there. What else can you find on bark? Moss? Mushrooms? Slime molds? Look closely--bark's a whole tiny world.

BITING DOWN

The beaver below is munching on bark. Porcupines do the same thing. Deer, moose, and some other animals also eat bark, but only if they're really hungry.

TRICKY TONGUE

The pileated (PIE-lee-ay-ted) woodpecker at right is a bark crack snacker. The bird sticks its l-o-n-g tongue into cracks and holes in the bark. Why? It's reaching for ants, beetles, and other tasty insect treats.

BARK FOR BABIES

The goshawk (GOSS-hawk) below isn't nibbling on bark--it's fixing its nest. Goshawks use pieces of bark to line their twiggy egg beds. Some songbirds also use bark to build nests.

People Use It...

BARK FACE

Many different groups of people use bark to make masks, like this one (above left) from the Pacific island of New Guinea. Bark is a good material for making masks. It curves around the face, and it can be carved and painted.

A-PEELING BARK

Bark from the paper birch tree is just about perfect for making stuff. It's tough. It's lightweight (so it's easy to carry). And it's easy to peel. (Peeling live bark usually harms the tree if it's not done right.)

People have made canoes, shelters, baskets, clothing, snowshoes, paper, and dishes out of birch bark.

The Malecite, Iroquois, Ojibway, and some other Indian tribes invented birch-bark canoes. They sewed great strips of birch bark together. Then they fastened the bark to a wooden frame (see photo at left).

This birch-bark canoe is nearly finished. The birch-bark teepee above is all done. See how those pieces of bark overlap one another? They work like roof shingles to keep out the rain.

WEARING BARK

Bark can be shredded and pounded to make stiff cloth. That's what the robe at right is made of. People on the Pacific island of Fiji wore robes like this one when they went to important ceremonies.

BARK IN A BOTTLE

Bet you've seen bottle corks, cork bulletin boards, and cork soles on shoes. Guess what--cork comes from bark!

Cork is full of millions of tiny air pockets. That's what makes it soft and spongy. That's also why cork is lightweight and floats so easily. Cork is also waxy, which helps make it waterproof.

All trees have a layer of cork in their bark. But a special kind of tree called cork oak has an extra-thick cork layer. To get the cork, workers strip big pieces of bark from large cork oak trees (right). It doesn't harm the tree if it's done the right way.

DR. BARK

If you take aspirin, thank a willow tree. Aspirin comes from a chemical that was first found in willow bark.

People make medicine from other kinds of tree bark too. A medicine used for a deadly disease called malaria first came from the quinine tree. And one made from a chemical in Pacific yew bark is used to treat some kinds of cancer.

DELICIOUS BARK

Do you like cinnamon rolls? Apple or pumpkin pie? Cinnamon toast? Then you like eating a kind of tree bark. Cinnamon comes from the inner bark of the cinnamon tree, which grows in Asia.

Bark Bytes

Here are even more uses for bark:

Shredded bark makes great mulch. People put a layer of mulch on their gardens to keep in moisture and stop weeds from growing.

Teas, dyes, and even poisons are made from boiled bark.

Long, stringy fibers of bark are used to make rope.