Henry David Thoreau founded our literature of trees, glorying in the Eastern White Pine as the “emblem of my life,” to stand for “the West, the wild.” His friend Emerson, one step closer, felt an “occult relation” between trees and himself. “They nod to me, and I to them,” he said. Now comes Richard Powers, novelist of science and astonishment, taking up that almost speaking connection “from the standpoint of the trees,” from the teeming crown of a giant Redwood, ever in motion, 200 feet or 20 stories above ground. In their own fight for survival, trees have their own way of knowing they’re key to our human hope of squeaking through the crash of species on a wounded planet Earth.

How quaint of Noah, it seems now, that when the world was ending the first time, he saved the animals, two by two, to regenerate the earth—but left the trees and plants to die. We begin to see the egotism of a species learning very late in the day how vanishing trees used to suck up the carbon and synthesize the oxygen that sustains us free-loaders on the life of trees. The decorated novelist Richard Powers is back with the trees’ side of a hard story.

Powers is the artist who keeps reinventing himself in difficult trades—brain science and modern musical composition before this. And now: The Overstory, about Trees: Lean into the trunk of a pine tree or an oak, a beech or an alder and listen, Rick Powers is telling us: if our minds were a little greener, we’d learn that trees created our soil and cycle our water, make the weather, build the air—and that the tree population we found on this planet is 95 percent gone. We are back in school with Richard Powers after a 5-year interval—this time in a living museum of trees from ancient times and all the world, the Arnold Arboretum in Boston.

We’re joined by Ned Friedman, director of the Arboretum, and the naturalist Diana Beresford-Kroeger, star of the new documentary Call of the Forest.