From the brains behind brains on, this is The Moment of Um.

Answering those questions that make you go.

The moment of um um um comes to you from APM Studios. I'm Molly Bloom. Have you ever hugged a tree? I have. I love it. It's so comforting to wrap your arms around something as old and mighty as a big oak tree. But if you are a regular tree hugger, you probably notice trees are not soft. In fact, they can be bumpy, prickly, and sometimes they scrape your skin.

That's because trees are covered in tree armor or bark. One of our listeners had a question

about this important part of a tree's anatomy. My name's Lois. My question is, why is the tree bark made out of?

Bye.

Bark, the rough outer shell of a tree, gets a lot less attention

than the really pretty colorful flowers on a plant.

Nevertheless, it's still extremely important.

My name is Diana Macias. I am a PhD student at the University of New Mexico.

I am a forest ecologist that studies how different populations of trees respond to drought.

First, bark makes trees really strong and stops gravity and wind from knocking them over.

And second, bark protects the sugars and waters from the trees that trees need to grow,

but it also helps with their movement.

The giant trees that we see today

are only possible because of tree bark. So what is tree bark made of? If we take a chainsaw

and cut a horizontal line into a tree and look at it from above, we'll see that the main

parts of the tree bark are the outer bark, which I call the armor, and the inner bark, which

I call the sugar pipeline. The smooth, cracked, scaly, or wrinkled bark that we all see and feel

is the outer bark that makes up the outer part of the tree and is made up by dead cells.

Trees need to have armor to protect themselves because they can't move like animals.

Trees cannot hide from the sun when they overheat. They cannot run away from a hungry

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