It’s clear that Silverstein, who grew up in Chicago in the 1930s, did not set out to write things for kids. In fact, he hated most children’s literature. To Silverstein, the classics and contemporary books alike were trash, though he had a soft spot for Dr. Suess. But as for old stand-bys like Charlotte’s Web, Stuart Little — “Those damn books are so bad they’re beautiful,” he once said, according to A Boy Named Shel, a 2011 biography by Lisa Rogak. “The condescension is not only thick enough to walk on, but absolutely destructive.” So when a friend suggested he start penning picture books, he thought it was far-fetched; Silverstein was known mainly for drawing offbeat cartoons for Playboy magazine, and was a regular visitor of the Playboy Mansion.

Today, the way people think about the benefits of trees has changed. Sure, they still provide shelter, having been sawed and hammered into the boxy shapes of homes, furnished with wooden beds, desks, cabinets, and more. But their invisible advantages are starting to get more attention, from the health benefits of walking through the woods to their ability to absorb huge amounts of carbon dioxide, the main greenhouse gas behind climate change. About 20 years ago or so, Watkins planted a small, three-acre woods. “Carbon sequestration was the last thing on my mind,” he said. “I wanted to grow trees for nature conservation, for beauty and whatever, but now 25 years on, I look at these trees and I think, ‘Wow, look at all that carbon that’s being sequestered!’”

Silverstein wrote a book that could be about anything. The choice to depict the giver as a tree may be what left the possibilities for interpretation so wide open.

I gave the students in my General Ecology class a survey. Among other things, they were asked to rate their understanding of the negative interactions between humans and the environment. Nearly every one of the two hundred students said confidently that humans and nature are a bad mix. These were third-year students who had selected a career in environmental protection, so the response was, in a way, not very surprising. They were well schooled in the mechanics of climate change, toxins in the land and water, and the crisis of habitat loss. Later in the survey, they were asked to rate their knowledge of positive interactions between people and land. The median response was “none.”

I have Bruce King’s portrait of Skywoman, Moment in Flight, hanging in my lab. Floating to earth with her handful of seeds and flowers, she looks down on my microscopes and data loggers. It might seem an odd juxtaposition, but to me she belongs there. As a writer, a scientist, and a carrier of Skywoman’s story, I sit at the feet of my elder teachers listening for their songs.

On one side of the world were people whose relationship with the living world was shaped by Skywoman, who created a garden for the well-being of all. On the other side was another woman with a garden and a tree. But for tasting its fruit, she was banished from the garden and the gates clanged shut behind her. That mother of men was made to wander in the wilderness and earn her bread by the sweat of her brow, not by filling her mouth with the sweet juicy fruits that bend the branches low. In order to eat, she was instructed to subdue the wilderness into which she was cast.

There are many different ways to draw the spotlight of other people’s attention—and all of them instinctively or deliberately tap into basic human drives. Here, for example, is a very short story attributed to Ernest Hemingway. For Sale: Baby shoes, never worn. How does this story make you feel? I can speak for myself: When I first encountered it as an undergraduate, my attention was instantly captured. And when I realized, after a beat, what it meant, I felt punched in the gut.

As we see fictional characters interact, our bodies tend to release a neuropeptide called oxytocin, which scientists first found in nursing mothers. Oxytocin has subsequently turned up in studies of couples and group-bonding—indeed, we find oxytocin whenever humans feel close to each other, or even just imagine being close. That’s why stories trigger oxytocin: When Princess Leia finally told Han Solo that she loves him in The Empire Strikes Back, your body almost certainly released at least a trace level. That’s not all that’s happening as we become involved in a story and its characters. The brain activity of both storytellers and story listeners starts to align thanks to mirror neurons, brain cells that fire not only when we perform an action but when we observe someone else perform the same action. As we become involved with a story, fictional things come to seem real in our bodies. The storyteller describes a delicious meal and the listener’s mouth can start to water. When the characters in the story feel sad, the listener’s left prefrontal cortex activates, suggesting that they feel sad, as well.

Study after study after study finds that stories are far more persuasive than just stating the facts. For example, one found that a storytelling approach was more effective in convincing African Americans at risk for hypertension to change their behavior and reduce their blood pressure. A study of low-performing science students found that reading stories of the struggles of famous scientists led to better grades. A paper published last year found that witnessing acts of altruism and heroism in films led to more giving in real life.