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The Body Language of Trees

Tim Slover

I have a small white scar on my elbow. It’s from a dog bite I got on my newspaper route in 7th grade. I’ve long imagined throwing a “scar party,” in which my guests take turns describing the marks left on their bodies by events that might have been otherwise forgotten.

So, what about trees — what of their history can we read from their bodies?

On a recent walk in Liberty Park, I noticed an odd branch on a small maple tree that started growing horizontally but then took a sharp vertical turn. A raised circular collar of scar tissue revealed that the branch above it had broken off. In response, the lower branch grew upward instead of outward, a record of an earlier injury.

Mountain trees strategically grow different types of wood that resolve the stresses imposed by wind and heavy snow loads. A spruce tree grows "tension wood" on its trunk's uphill side and wider-ringed "compression wood" on its lower side, which creates a big bellied trunk to let the tree straighten up and stand tall.

One tree that silently conveys its history is the 70-year-old Cedar of Lebanon that stands at the east entrance to Salt Lake City's Temple Square. Years ago, the tree survived a potentially fatal blow when a chunk of ice fell from the temple's roof, completely shearing off the tree’s top. Gardeners guided a lateral branch to grow vertically, leaving a distinct wiggle in its trunk.

But any time you walk in our city or forests, take a moment to appreciate the body language of trees. Without words, the arc of a branch or the slant of a trunk reveals that trees can survive damage and carry on living — their scars giving voice to their stories.

Dr. Nalini Nadkarni is an emeritus professor of both The Evergreen State College and the University of Utah, one of the world’s leading ecologists and a popular science communicator. Dr. Nadkarni’s research and public engagement work is supported by the National Geographic Society and the National Science Foundation. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. @nalininadkarni
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