The latest volume follows a similar pattern. Tree leaves, we read, possess transparent lens-like cuticles that may function as primitive eyes. Trees can “hear” water flowing deep within the ground and angle their roots to retrieve it. And they even display something resembling a heartbeat as they pump their sap at regular intervals, once every three or four hours.
However differently we function, humans share much of our DNA and even our physiology, at least by analogy, with plants. Trees’ sensitive root tips, for example, function like neurons in a kind of vegetable brain, Wohlleben suggests. A far-fetched idea, one might think, until the author reveals that Charles Darwin postulated the very same thing in the mid-19th century.
Are plants conscious? The author is coyly noncommittal. He quotes German biologist Frantisek Baluska in a New York Times interview: “No one can answer this because you cannot ask [the plants].”
Nevertheless, the circumstantial evidence provided in the book is intriguing. Trees possess memory, Wohlleben tells us, and can pass those memories on epigenetically to their offspring. Moreover, their activities can be suppressed by the same anesthetics that are used on people. And — tree-huggers take note — trees appear to use a voltage-based signaling system that is similar to animal nervous systems. So while they won’t exactly feel your embrace through the dead carapace of their bark, they might sense you as an electrical presence lurking restlessly at their periphery.
The author’s aim in the current volume, however, is less to dazzle us with odd speculations like these than to convince us that trees are more like us than we had imagined. Humans are destroying forests because they lack empathy with their denizens, he says. To protect them, we first of all need to understand that we are integral parts of — rather than apart from — the living world.
“The ancient tie that binds us to nature is not and never has been severed,” Wohlleben insists, though we have temporarily lost sight of that bond as a result of our modern mania to dominate nature and exploit it.
The good news is that we can recover our feeling of being connected to trees — and to the rest of the natural world — if we fully awaken our senses. For starters, we’ll need to look up from our cellphones now and again and spend more time in the woods, where our latent abilities to fully hear, feel, smell and see the fine details of the world will come alive.
Prepare to be surprised by your own capabilities, Wohlleben writes. Humans sometimes think that their brains are powerful but that their senses are weak. Dogs, we are told, have more discerning senses of smell and hearing than we do, and birds of prey can see a rodent scurrying in the grass from hundreds of feet away.
True enough, the author says. But people can do things that other creatures cannot. Unlike dogs and dolphins, for example, we can see the color green, a boon when wandering through the forest or looking for berries and plants to eat. While dogs can track the scents of prey animals in the woods, humans outperform canines in smelling ripe fruit, and we can sniff out testosterone and DNA in potential mates to help us choose the right match.
The point Wohlleben is making is that we are fully equipped to flourish in nature because we are nature. Our evolutionary history, no less than that of trees, has fitted humans to live in forests, grasslands and other wild places. That is why a walk in the woods lowers our blood pressure, brightens our mood and strengthens the functioning of our immune system. We feel at home there. Wohlleben cites research showing that even a dozen trees planted in a residential neighborhood can extend the life span of residents by more than a year, compared with individuals who dwell on treeless streets.
“The Heartbeat of Trees” comprises 31 short chapters that take us on a whirlwind tour, including a trip to the world’s oldest tree in Sweden and its largest temperate rainforest in British Columbia, as well as visits with leading tree scientists and assorted forest activists.
The wide range of the subjects he tackles and the meandering, unfocused style of the writing can be irritating. There is enough to whet our curiosity here but not to satisfy it. For those looking for more scientific meat on the bone, ecologist Suzanne Simard’s recently published “Finding the Mother Tree” may be a better option.
Wohlleben is like a knowledgeable uncle who takes you in hand and talks your ear off about whatever he’s thinking at the moment. “The Heartbeat of Trees” is less a well-organized book than a sometimes stumbling and circuitous ramble through the woods without any particular goal. You may not arrive at any definite destination, but you’ve seen lots of interesting things along the way.
The Heartbeat of Trees
Embracing Our Ancient Bond With Forests
By Peter Wohlleben
Translated by Jane Billinghurst
258 pp. $26.95