One tree’s personal climate change story

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Lynda Mapes, an environmental reporter with the Seattle Times, was looking for a different way to tell the story of climate change.

“I was sick of the way we’d somehow started telling it as reporters — parts per billion, dueling treaties, arguing politicians — I didn’t want to hear anything more about that.”

Mapes told To the Point the technique she’s settled on is “the testimony of living things.” She likes to say that trees are the “original historians and the first reporters,” and that leaves don’t spread fake news. The result is her new book “Witness Tree: Seasons of Change with a Century-Old Oak.

First she had to find a tree. She auditioned several, including a striped maple and a black gum tree. She decided on a “big, beautiful old red oak,” which is the most common species in the Northern Hemisphere.

With the help of MIT researchers, she used new technology and old-school phenology — the observation of regular seasonal changes in nature — to track how global warming has changed her tree. MIT has engineered what they call “a digital observatory” of about 300 trees by putting up security cameras on 120-foot high towers and watching for seasonal changes in the tree canopy. Along with close-up measurements, these details capture how the tree is growing differently now from, say, 20 years ago.

The witness tree sprouted back in 1905, “when the Ford Model T first started rattling off the assembly line” Mapes said. Carbon emissions have skyrocketed since. “We were able to see actual physical changes in the tree. The leaves act differently, “growing faster and more efficiently than at any time than the last 20 years.”

The effect of global warming is noticeable in the rings of a tree, too. This is something most American school children have learned about. And it was that childhood curiosity Mapes hopes will connect people with this story.

“I didn’t want to scold or scare. I wanted to touch people in their hearts.”

(Photo: Tree canopy by Jim Stanton)