Over the years I would encounter other mentions of the same extraordinary idea, and gradually these isolated fragments began to connect together into something like understanding. It was planted in my mind, and there took root. But I could not forget the image of that mysterious buried network, joining single trees into forest communities. He did not have the strength then to tell me the details of how this belowground sharing operated-how tree might invisibly reach out to tree within the soil. It was a measure of my friend’s generosity of spirit that-so close to death himself-he could speak unjealously of this phenomenon of healing. Then he told me about new research he had recently read concerning the interrelations of trees: how, when one of their number was sickening or under stress, they could share nutrients by means of an underground system that conjoined their roots beneath the soil, thereby sometimes nursing the sick tree back to health. That day I read aloud a poem that was important to us both, “Birches” by Robert Frost, in which climbing the snow-white trunks of birches becomes both a readying for death and a declaration of life. His grandfather’s surname was Wood, he lived in a timber-framed house that he had built himself, and he had planted thousands of trees by hand over the years. I had gone to see him for what I took to be the last time.

A beloved friend was dying too young and too quickly. The first time I heard anyone speak of the “wood wide web,” more than a decade ago now, I was trying not to cry. Occasionally-once or twice in a lifetime if you are lucky-you encounter an idea so powerful in its implications that it unsettles the ground you walk on. Encountering the depth and complexity of communication that happens underground, Robert returns to the entangled mutualism at the root of language. Excerpted from his recently published book, Underland: A Deep Time Journey, “The Understory” is an examination of the life beneath the forest floor.

Merlin sheldrake mushrooms