HUMMEL, Germany — In the deep stillness of a forest in winter, the sound of footsteps on a carpet of leaves died away. Peter Wohlleben had found what he was looking for: a pair of towering beeches. "These trees are friends," he said, craning his neck to look at the leafless crowns, black against a gray sky. "You see how the thick branches point away from each other? That's so they don't block their buddy's light."
Before moving on to an elderly beech to show how trees, like people, wrinkle as they age, he added, "Sometimes, pairs like this are so interconnected at the roots that when one tree dies, the other one dies, too."
Wohlleben, 51, is a very tall career forest ranger who, with his ramrod posture and muted green uniform, looks a little like one of the sturdy beeches in the woods he cares for. Yet he is lately something of a sensation as a writer in Germany, a place where the forest has long played an outsize role in the cultural consciousness, from fairy tales to 20th century philosophy, Nazi ideology and the birth of the modern environmental movement.
After the publication in May of Wohlleben's book, a surprise hit titled The Hidden Life of Trees: What They Feel, How They Communicate — Discoveries From a Secret World, the German forest is back in the spotlight. Since it first topped bestseller lists last year, Wohlleben has been spending more time on the media trail and less on the forest variety, making the case for a popular reimagination of trees, which, he says, contemporary society tends to look at as "organic robots" designed to produce oxygen and wood.
Presenting scientific research and his own observations in highly anthropomorphic terms, the matter-of-fact Wohlleben has delighted readers and talk show audiences alike with the news — long known to biologists — that trees in the forest are social beings. They can count, learn and remember; nurse sick neighbors; warn each other of danger by sending electrical signals across a fungal network known as the "Wood Wide Web"; and, albeit for reasons unknown, keep the ancient stumps of long-felled companions alive for centuries by feeding them a sugar solution through their roots.
"With his book, he changed the way I look at the forest forever," Markus Lanz, a popular talk show host, said in an email. "Every time I walk through a beautiful woods, I think about it."
Though duly impressed with Wohlleben's ability to capture the public's attention, some German biologists question his use of words, like "talk" rather than the more standard "communicate," to describe what goes on between trees in the forest.
But this, says Wohlleben, who invites readers to imagine what a tree might feel when its bark tears ("Ouch!"), is exactly the point. "I use a very human language," he explained. "Scientific language removes all the emotion, and people don't understand it anymore. When I say 'Trees suckle their children,' everyone knows immediately what I mean."
Still No. 1 on the Spiegel best-seller list for nonfiction, The Hidden Life of Trees has sold about 320,000 copies and has been optioned for translation in 19 countries (Canada's Greystone Books will publish an English version in September). "It's one of the biggest successes of the year," said Denis Scheck, a German literary critic who praised Wohlleben's humble narrative style and ability to awaken in readers an intense, childlike curiosity about the workings of the world.
Wohlleben traces his own love of the forest to his early childhood. Growing up in the 1960s and '70s in Bonn, then the West German capital, he raised spiders and turtles and liked playing outside more than any of his three siblings did. In high school, a generation of young, left-leaning teachers painted a dire picture of the world's ecological future, and Wohlleben decided it was his mission to help.
He studied forestry, and began working for the state forestry administration in Rhineland-Palatinate in 1987. Later, as a young forester in charge of a 3,000-odd acre woodlot in the Eifel region, about an hour outside Cologne, he felled old trees and sprayed logs with insecticides. But he did not feel good about it: "I thought, 'What am I doing? I'm making everything kaput.'"
Reading up on the behavior of trees — a topic he learned little about in forestry school — Wohlleben discovered that, in nature, trees operate less like individuals and more as communal beings. Working together in networks and sharing resources, they increase their resistance to threats.
By artificially spacing out trees, the plantation forests that make up most of Germany's woods ensure that trees get more sunlight and grow faster. But, naturalists say, creating too much space between trees can disconnect them from their networks, stymieing some of their inborn resilience mechanisms.
Wohlleben wanted to write The Hidden Life of Trees to show laypeople how great trees are.
Stopping to consider a tree that rose up straight then curved to the side, like a question mark, Wohlleben said, however, that it was the untrained perspective of visitors he took on forest tours years ago to which he owed much of his insight.
"For a forester, this tree is ugly, because it is crooked, which means you can't get very much money for the wood," he said. "It really surprised me, walking through the forest, when people called a tree like this one beautiful. They said, 'My life hasn't always run in a straight line, either.' And I began to see things with new eyes."