"The wood wide web”—Robert Macfarlane's latest peers beneath the earth

If nature writer Robert Macfarlane were a poet, he would be an imagist. Everything is in the present tense, using very short sentences, often without a verb. This is from his new book Underland: “Late summer heatwave, heavy air. Bees browsing drowsy over meadow grass. Gold of standing corn, green of fresh hay-rows, black of rooks on stubble fields.” In the hands of a less accomplished writer this might be difficult to sustain. But Macfarlane is a virtuoso who manages this tightrope walking.

While his previous outings like The Wild Places and The Old Ways were bravura trips through the well-trodden overground, now he lights out for what is genuinely new literary territory: the underworld. The book is a genre-defying exploration of “the earth’s vast subterrane as it exists in myth, memory and place itself.” There is science, history and much more besides.

He describes how trees mutually support one another through an underground social network—dubbed “the wood wide web”—of fungal species, sharing nutrients if one of them is dying. Instead of seeing trees as individual agents, we should understand-—and emulate—the forest as a cooperative system, producing a shared intelligence. Macfarlane’s account of this radical new idea is passionate and scholarly.

He canters over subjects in fascinating and unexpected ways, from Walter Benjamin to lost cities buried underground. Like Ariadne, he always leaves a thread for the reader to follow—we have placed in the underworld that which we fear, but also love and wish to save.

This book is not for the fainthearted. Someone tells Macfarlane to “keep up” as he hurtles through the Parisian catacombs and the reader may occasionally feel the same. But the rewards of following him as he burrows deep into the underland are considerable. This extraordinary book will be mined by future generations.

Underland: A Deep Time Journey by Robert Macfarlane is published by Hamish Hamilton (£20)