“One must possess oneself, and be alone in possession of oneself.”
By Maria Popova
To walk among trees is to be reminded that although relationships weave the fabric of life, one can only be in relationship — in a forest or a family or a friendship — when firmly planted in the sovereignty of one’s own being, when resolutely reaching for one’s own light.
A century ago, Hermann Hesse contemplated how trees model for us this foundation of integrity in his staggeringly beautiful love letter to trees — how they stand lonesome-looking even in a forest, yet “not like hermits who have stolen away out of some weakness, but like great, solitary men, like Beethoven and Nietzsche.” Celebrating them as “the most penetrating preachers,” he reverenced the silent fortitude with which “they struggle with all the force of their lives for one thing only: to fulfill themselves according to their own laws, to build up their own form, to represent themselves.”
A supreme challenge of human life is reconciling the longing to fulfill ourselves in union, in partnership, in love, with the urgency of fulfilling ourselves according to our own solitary and sovereign laws. Writing at the same time as Hesse, living in exile in the mountains, having barely survived an attack of the deadly Spanish Flu that claimed tens of millions of lives, the polymathic creative force D.H. Lawrence (September 11, 1885–March 2, 1930) took up the question of this divergent longing with great subtlety and splendor of insight in his autobiographically tinted novel Aaron’s Rod (free ebook | public library), rooting the plot’s climactic relationship resolution in a stunning passage about trees.
At a tea-party, the novel’s protagonist meets the Marchesa del Torre — an American woman from the South, married to an Italian man and living with him in Tuscany; a woman of composure with an edge of beckoning aloofness, “sitting there, full-bosomed, rather sad, remote-seeming,” a kind of modern Cleopatra brooding from under her dark, heavy-hanging hair out of an Aubrey Beardsley drawing. She strikes him as “wonderful, and sinister,” affects him “with a touch of horror.” He falls under her spell, drawn to her as we are so often drawn to danger by the magnetic pull of the sublime, with its dipoles of beauty and terror.
When their affair collapses under the weight of its own impossibility, he finds himself — and finds his self, his sovereignty of soul — among the trees. Lawrence writes:
One must possess oneself, and be alone in possession of oneself.
He sat for long hours among the cypress trees of Tuscany. And never had any trees seemed so like ghosts, like soft, strange, pregnant presences. He lay and watched tall cypresses breathing and communicating, faintly moving and as it were walking in the small wind. And his soul seemed to leave him and to go far away, far back, perhaps, to where life was all different and time passed otherwise than time passes now. As in clairvoyance he perceived it: that our life is only a fragment of the shell of life. That there has been and will be life, human life such as we do not begin to conceive. Much that is life has passed away from men, leaving us all mere bits. In the dark, mindful silence and inflection of the cypress trees, lost races, lost language, lost human ways of feeling and of knowing. Men have known as we can no more know, have felt as we can no more feel. Great life-realities gone into the darkness. But the cypresses commemorate.
“In their highest boughs the world rustles, their roots rest in infinity; but they do not lose themselves there, they struggle with all the force of their lives for one thing only: to fulfill themselves according to their own laws… to represent themselves. Nothing is holier, nothing is more exemplary than a beautiful, strong tree.”
By Maria Popova
In the final years of his life, the great neurologist Oliver Sacks reflected on the physiological and psychological healing power of nature, observing that in forty years of medical practice, he had found only two types of non-pharmaceutical therapy helpful to his patients: music and gardens. It was in a garden, too, that Virginia Woolf, bedeviled by lifelong mental illness, found the consciousness-electrifying epiphany that enabled her to make some of humanity’s most transcendent art despite her private suffering.
When my dear friend Natascha McElhone (who narrated Figuring) was asked to choose a piece of literature with which to narrate a tour of the Royal Botanic Gardens, Kew, for an episode of Wander — a lovely series by filmmaker Beau Kerouac, benefiting Britain’s Mental Health Foundation and helping quarantined people virtually visit some of the world’s most beloved parks and cultural institutions, accompanied by some of the world’s most beloved literary and artistic voices — Natascha chose a wondrous 100-year-old love letter to trees by Hermann Hesse (July 2, 1877–August 9, 1962), which she had saved from Brain Pickings nearly a decade ago. Originally published in Hesse’s 1920 collection of fragments, Wandering: Notes and Sketches (public library), it comes newly alive in this transportive, transcendent journey through the screen and past it, into a lush wonderland of nature’s aliveness, with two uncommonly beautiful voices as the sherpas.
For me, trees have always been the most penetrating preachers. I revere them when they live in tribes and families, in forests and groves. And even more I revere them when they stand alone. They are like lonely persons. Not like hermits who have stolen away out of some weakness, but like great, solitary men, like Beethoven and Nietzsche. In their highest boughs the world rustles, their roots rest in infinity; but they do not lose themselves there, they struggle with all the force of their lives for one thing only: to fulfill themselves according to their own laws, to build up their own form, to represent themselves. Nothing is holier, nothing is more exemplary than a beautiful, strong tree. When a tree is cut down and reveals its naked death-wound to the sun, one can read its whole history in the luminous, inscribed disk of its trunk: in the rings of its years, its scars, all the struggle, all the suffering, all the sickness, all the happiness and prosperity stand truly written, the narrow years and the luxurious years, the attacks withstood, the storms endured. And every young farmboy knows that the hardest and noblest wood has the narrowest rings, that high on the mountains and in continuing danger the most indestructible, the strongest, the ideal trees grow.
Trees are sanctuaries. Whoever knows how to speak to them, whoever knows how to listen to them, can learn the truth. They do not preach learning and precepts, they preach, undeterred by particulars, the ancient law of life.
A tree says: A kernel is hidden in me, a spark, a thought, I am life from eternal life. The attempt and the risk that the eternal mother took with me is unique, unique the form and veins of my skin, unique the smallest play of leaves in my branches and the smallest scar on my bark. I was made to form and reveal the eternal in my smallest special detail.
A tree says: My strength is trust. I know nothing about my fathers, I know nothing about the thousand children that every year spring out of me. I live out the secret of my seed to the very end, and I care for nothing else. I trust that God is in me. I trust that my labor is holy. Out of this trust I live.
When we are stricken and cannot bear our lives any longer, then a tree has something to say to us: Be still! Be still! Look at me! Life is not easy, life is not difficult. Those are childish thoughts… Home is neither here nor there. Home is within you, or home is nowhere at all.
A longing to wander tears my heart when I hear trees rustling in the wind at evening. If one listens to them silently for a long time, this longing reveals its kernel, its meaning. It is not so much a matter of escaping from one’s suffering, though it may seem to be so. It is a longing for home, for a memory of the mother, for new metaphors for life. It leads home. Every path leads homeward, every step is birth, every step is death, every grave is mother.
So the tree rustles in the evening, when we stand uneasy before our own childish thoughts: Trees have long thoughts, long-breathing and restful, just as they have longer lives than ours. They are wiser than we are, as long as we do not listen to them. But when we have learned how to listen to trees, then the brevity and the quickness and the childlike hastiness of our thoughts achieve an incomparable joy. Whoever has learned how to listen to trees no longer wants to be a tree. He wants to be nothing except what he is. That is home. That is happiness.
“We are idealists and we are realists. We are dreamers and we are builders. We are experiencers and we are experimenters. We long for certainties, yet we ourselves are full of the ambiguities of the Mona Lisa and the I Ching. We ourselves are a part of the yin-yang of the world.”
It is, of course, an abiding question, as old as consciousness — we are material creatures that live in a material universe, yet we are capable of experiences that transcend what we can atomize into physical facts: love, joy, the full-being gladness of a Beethoven symphony on a midsummer’s night.
The Nobel-winning physicist Niels Bohr articulated the basic paradox of living with and within such a duality: “The fact that religions through the ages have spoken in images, parables, and paradoxes means simply that there are no other ways of grasping the reality to which they refer. But that does not mean that it is not a genuine reality. And splitting this reality into an objective and a subjective side won’t get us very far.”
Nearly a century after Bohr, the physicist and writer Alan Lightman takes us further, beyond these limiting dichotomies, in Searching for Stars on an Island in Maine (public library) — a lyrical and illuminating inquiry into our dual impulse for belief in the unprovable and for trust in truth affirmed by physical evidence. Through the lens of his personal experience as a working scientist and a human being with uncommon receptivity to the poetic dimensions of life, Lightman traces our longing for absolutes in a relative world from Galileo to Van Gogh, from Descartes to Dickinson, emerging with that rare miracle of insight at the meeting point of the lucid and the luminous.
Lightman, who has previously written beautifully about his transcendent experience facing a young osprey, relays a parallel experience he had one summer night on an island off the coast of Maine, where he and his wife have been going for a quarter century. On this small, remote speck of land, severed from the mainland without ferries or bridges, each of the six families has had to learn to cross the ocean by small boat — a task particularly challenging at night. Lightman recounts the unbidden revelation of one such nocturnal crossing:
No one was out on the water but me. It was a moonless night, and quiet. The only sound I could hear was the soft churning of the engine of my boat. Far from the distracting lights of the mainland, the sky vibrated with stars. Taking a chance, I turned off my running lights, and it got even darker. Then I turned off my engine. I lay down in the boat and looked up. A very dark night sky seen from the ocean is a mystical experience. After a few minutes, my world had dissolved into that star-littered sky. The boat disappeared. My body disappeared. And I found myself falling into infinity. A feeling came over me I’d not experienced before… I felt an overwhelming connection to the stars, as if I were part of them. And the vast expanse of time — extending from the far distant past long before I was born and then into the far distant future long after I will die — seemed compressed to a dot. I felt connected not only to the stars but to all of nature, and to the entire cosmos. I felt a merging with something far larger than myself, a grand and eternal unity, a hint of something absolute. After a time, I sat up and started the engine again. I had no idea how long I’d been lying there looking up.
Lightman — the first professor at MIT to receive a dual faculty appointment in science and the humanities — syncopates this numinous experience with the reality of his lifelong devotion to science:
I have worked as a physicist for many years, and I have always held a purely scientific view of the world. By that, I mean that the universe is made of material and nothing more, that the universe is governed exclusively by a small number of fundamental forces and laws, and that all composite things in the world, including humans and stars, eventually disintegrate and return to their component parts. Even at the age of twelve or thirteen, I was impressed by the logic and materiality of the world. I built my own laboratory and stocked it with test tubes and petri dishes, Bunsen burners, resistors and capacitors, coils of electrical wire. Among other projects, I began making pendulums by tying a fishing weight to the end of a string. I’d read in Popular Science or some similar magazine that the time for a pendulum to make a complete swing was proportional to the square root of the length of the string. With the help of a stopwatch and ruler, I verified this wonderful law. Logic and pattern. Cause and effect. As far as I could tell, everything was subject to numerical analysis and quantitative test. I saw no reason to believe in God, or in any other unprovable hypotheses.
Yet after my experience in that boat many years later… I understood the powerful allure of the Absolutes — ethereal things that are all-encompassing, unchangeable, eternal, sacred. At the same time, and perhaps paradoxically, I remained a scientist. I remained committed to the material world.
Against our human finitude, temporality, and imperfection, these “Absolutes” offer infinity, eternity, perfection. Lightman defines them as concepts and beliefs that “refer to an enduring and fixed reference point that can anchor and guide us through our temporary lives” — notions like constancy, immortality, permanence, the soul, “God.”
A fascinating feature of the Absolutes — in fact, a defining feature — is that there is no way to get there from here, that is, from within the physical world. There is no gradual, step-by-step path to go from relative truth to absolute truth, or to go from a long period of time to eternity, or from limited wisdom to the infinite wisdom of God. The infinite is not merely a lot more of the finite. Indeed, the unattainability of the Absolutes may be part of their allure.
The final defining feature of these Absolutes, Lightman notes, is their unprovability by the scientific method. He writes:
Yet I did not need any proof of what I felt during that summer night in Maine looking up at the sky. It was a purely personal experience, and its validity and power resided in the experience itself. Science knows what it knows from experiment with the external world. Belief in the Absolutes comes from internal experience, or sometimes from received teachings and culture-granted authority.
Conversely, however, notions that belong to this realm of Absolutes fall apart when they make claims in the realm of science — claims disproven by the facts of the material world. With an eye to how the discoveries of modern science — from heliocentricity to evolution to the chemical composition of the universe — have challenged many of these Absolutes, Lightman writes:
Nothing in the physical world seems to be constant or permanent. Stars burn out. Atoms disintegrate. Species evolve. Motion is relative. Even other universes might exist, many without life. Unity has given way to multiplicity. I say that the Absolutes have been challenged rather than disproved, because the notions of the Absolutes cannot be disproved any more than they can be proved. The Absolutes are ideals, entities, beliefs in things that lie beyond the physical world. Some may be true and some false, but the truth or falsity cannot be proven.
From all the physical and sociological evidence, the world appears to run not on absolutes but on relatives, context, change, impermanence, and multiplicity. Nothing is fixed. All is in flux.
On the one hand, such an onslaught of discovery presents a cause for celebration… Is it not a testament to our minds that we little human beings with our limited sensory apparatus and brief lifespans, stuck on our one planet in space, have been able to uncover so much of the workings of nature? On the other hand, we have found no physical evidence for the Absolutes. And just the opposite. All of the new findings suggest that we live in a world of multiplicities, relativities, change, and impermanence. In the physical realm, nothing persists. Nothing lasts. Nothing is indivisible. Even the subatomic particles found in the twentieth century are now thought to be made of even smaller “strings” of energy, in a continuing regression of subatomic Russian dolls. Nothing is a whole. Nothing is indestructible. Nothing is still. If the physical world were a novel, with the business of examining evil and good, it would not have the clear lines of Dickens but the shadowy ambiguities of Dostoevsky.
Indeed, Dostoevsky himself may be the prophet laureate of Absolutes, for he asserted a lifetime ahead of Lightman that “nature, the soul, love, and God, one recognizes through the heart, and not through the reason.” The discoveries of reason, which Lightman terms the Relatives — “the relativity and impermanence and multiplicity found by modern science” — stand in counterpoint to the Absolutes, but these are not binary categories. Pointing to examples like the novelist Marilynne Robinson, whose highly spiritual writing is infused with science, and the Nobel-winning physicist Steven Weinberg, an atheist who nonetheless believes in a “final theory” that promises absolute answers to all of existence, Lightman notes that individual people weave Absolutes and Relatives into their worldview in varying degrees. He writes:
The Absolutes and the Relatives can be considered a large frame in which to view the dialogue between religion and science, or between spirituality and science. But I suggest that the issues go deeper, into the dualism and complexity of human existence. We are idealists and we are realists. We are dreamers and we are builders. We are experiencers and we are experimenters. We long for certainties, yet we ourselves are full of the ambiguities of the Mona Lisa and the I Ching. We ourselves are a part of the yin-yang of the world. Our yearning for absolutes and, at the same time, our commitment to the physical world reflect a necessary tension in how we relate to the cosmos and relate to ourselves.
When I was seven or eight years old, growing up in landlocked Memphis, I visited my grandparents for a week at their little beach house in Miami. One dark and moonless night as I sat at the end of their dock, for some reason known only to children I grabbed a stick and stirred up the ocean beneath me. I was astonished to see the water shimmer with light. To my mind, the ocean was already a mysterious place, with its changing colors, its infinite gray skin stretching out to the sky, and its waves flowing in one after another, like the breathing of some large sleeping animal. But the glow of the seawater was magic of a different order. My imagination flared. Was this fairy dust? Was this some kind of galactic energy? What other secrets and powers lay below the ocean’s surface? Excited, I ran into the house and commandeered my grandparents to witness the discovery. Again I stirred the water with my wand, and it happened again. Pure magic. I scooped up some of the supernatural liquid in a glass jar and took it into the house for further inspection. I’m not sure what I was hoping to find. What I did find, after the water settled, were tiny organisms floating about. In a dark room, they glowed faintly like fireflies. They felt slightly grainy in my hand. I was crestfallen. The magic was just little bugs in the water.
That dual fascination with wonder and reverence for fact never left Lightman. He reflects sixty years later:
As did Thoreau in Concord, I’ve traveled far and wide on Lute Island. I know each cedar and poplar, each clump of beach rose, Rosa rugosa, each patch of blueberry bushes and raspberry brambles and woody stems of hydrangeas, all the soft mounds of moss, some of which I touch on my ramblings today. The tart scent of raspberries blends with the salty sea air. Early this morning, a fog enveloped the island so completely that I felt as if I were in a spaceship afloat in outer space — white space. But the surreal fog, made of minuscule water droplets too tiny to see, eventually evaporated and disappeared. It’s all material, even the magical fog — like the bioluminescence I first saw as a child. It’s all atoms and molecules.
The materiality of the world is a fact, but facts don’t explain the experience. Shining sea water, fog, sunsets, stars. All material. So grand is the material that we find it hard to accept it as merely material… Surely, there must be more. “Nature,” wrote Emily Dickinson, “is what we see / The Hill — the Afternoon / Squirrel — Eclipse — the Bumble bee / Nay — Nature is Heaven.” In the last line, the poet leaps from the finite to infinity, to the realm of the Absolutes. It is almost as if Nature in her glory wants us to believe in a heaven, something divine and immaterial beyond nature itself. In other words, Nature tempts us to believe in the supernatural. But then again, Nature has also given us big brains, allowing us to build microscopes and telescopes and ultimately, for some of us, to conclude that it’s all just atoms and molecules. It’s a paradox.
For millennia, we have been aiming our range of tools — from mythology to science — at this paradox, but remain suspended between Absolutes and Relatives even as we make progress in fathoming the reality of nature on its own terms. Lightman writes:
Nature may at times appear to be a Painter or a Philosopher or a Celestial Spirit. But deep down she is a Scientist. She is quantitative. She is logical. And nothing better illustrates her ruthless and unyielding adherence to that logic than the law of the conservation of energy. Energy does not appear out of nothing. Energy does not disappear into nothing. The energy law is a sacred cow of physics.
Two thousand years ago, the Roman poet and philosopher Lucretius suggested that the power of the gods over us mortals is limited by the constancy of atoms. Atoms could not be created or destroyed, said Lucretius. The gods could not make objects suddenly appear out of nothing or vanish into nothing because all things are made out of atoms, and the number of atoms remains constant… Lucretius’s idea was a conservation law. The poet did not know how to tally up the number of atoms, as we tally up the number of joules in a box, but something was constant, and that constancy clearly provided great psychological comfort as well as understanding of nature. Let the gods and the supernatural have their sway, but they cannot alter the number of atoms here in our earthly world.
Lightman observes that when modern physics arrived at the law of conservation of energy, affirmed by the discovery of the neutrino, it provided the same psychological comfort:
With this law and others like it, nature can be made sense of. Nature can be calculated. Nature can be depended on. If you know the initial energy of the unstruck match and then measure the energy in the heated air, you know how high the weight must be lifted. The total energy is constant.
Ironically, we have traded one constancy for another. We have lost the constancy of the stars but gained the constancy of energy. The first is a physical object, the second a concept. Scientists cannot prove without a doubt that the total energy in a closed system is constant. But any violation of that principle would destroy the foundations of physics and suggest an unlawful universe. The idea of a lawful universe is itself an Absolute.
The material of the doomed stars and the material of my doomed body are actually the same material. Literally the same atoms… It is astonishing but true that if I could attach a small tag to each of the atoms of my body and travel with them backward in time, I would find that those atoms originated in particular stars in the sky. Those exact atoms.
Human life may be a beautiful fact, but it is a tiny subset of the facts of the universe — a universe we took for millennia to belong to us. We are only just beginning to recognize that we belong to it. There is disquiet in this recognition that bleeds into denial — denial encoded in the statistic that the vast majority of people in the world still believe in a personal God who intercedes on their behalf, a belief predicated on the delusion of human centrality and our special status amid a cosmos of incomprehensible vastness. Lightman calibrates that notion with the facts of reality:
Data from the Kepler astronomical satellite, launched in 2009 and specifically constructed to search for planets in the “habitable zone” — that is, the right distance from their central star to possess liquid water — suggest that something like 10 percent of all stars have at least one “habitable” planet…
There are several hundred billion stars in our galaxy alone, and a hundred billion galaxies just within the observable universe. Overwhelmingly, the odds favor life forms elsewhere in the universe. Although we do not know in detail how life developed on earth, the odds that no life exists on the billions and billions of other habitable planets would be as improbable as no fires ever starting in a billion trillion dry forests. Almost certainly life elsewhere in the universe would not be like ours. But biologists and even perhaps artists and philosophers would recognize it as life. And with so many life-bearing worlds and billions of years of cosmic evolution, there must be a range of civilizations, some less advanced than ours and some more.
What God, Lightman asks, would be able to meet the demands of so many worlds and still prioritize the particular needs of each individual in our particular civilization orbiting our particular third-rate star? What gives meaning to our existence, he suggests, is not the guarantee of Absolutes or the favors of some imagined cosmic deity but something else entirely — something that fills the smallest units of our temporality with life until they themselves expand into a testament to the age-old insight that “all eternity is in the moment.” He writes:
Nothing is absolutely motionless, says Einstein, but I’m centered in this island. Wherever it goes, hurtling through space as the earth orbits the sun and the sun orbits the galaxy, I go with it. I’ve planted myself here, like the Rosa rugosa down the hill, stubborn and thorny. At this moment, I can hear the call of a gull and the wind blowing through trees like the sound of a distant waterfall and the tiny purr of a boat engine far off in the bay. Then there’s the steady and slight sound of the waves, playing counterpoint to the soft music of birds. But all of it slips into the silky silence of this place. I embrace that silence. I breed silence and am bred by it. On this island, I am light years away from the noise and heave of the world. Like Thoreau, I came here “because I wished to live deliberately, to front only the essential facts of life, and see if I could not learn what life had to teach, and not, when I came to die, discover that I had not lived.” I choose to live. Now, this body of mine, this old animal, is sixty-seven years old.
Echoing Montaigne — “To lament that we shall not be alive a hundred years hence, is the same folly as to be sorry we were not alive a hundred years ago,” observed the father of the essay as he contemplated mortality and the art of living in the same century Galileo unsettled the universe — Lightman writes:
When we approach Lute Island by boat and gaze at it from a distance, a dollop of rock and green rising out of the sea, I am acutely aware that it will last far longer than I will. A hundred years from now, after I’m gone, many of these spruce and cedars will still be here. And the wind going through them will sound like a distant waterfall. The curve of the land will be the same as it is now. The paths that I wander may still be here, although probably covered with new vegetation. The rocks and ledges on the shore will be here, including a particular ledge I’m quite fond of, shaped like the knuckled back of a large animal. Sometimes, I sit on that ledge (more sitting) and wonder if it will remember me. Even my house might still be here, or at least the concrete posts of its footing, crumbling in the salt air. But eventually, of course, even this island will shift and change and dissolve. In geologic time, there may be no trace of Lute Island. Twenty-five thousand years ago, it didn’t exist. Maine and most of North America were covered with ice, thousands of feet thick. Two hundred and fifty million years ago, the Atlantic Ocean didn’t exist. Europe, Africa, and North America were joined together in a single landmass. Nothing persists in the material world. All of it changes and passes away.
As I lie in my hammock now on this late afternoon in August, I can feel the seconds ticking away to my end, and I believe it to be a final end. But that finality does not diminish the grandeur of life. As the seconds tick by, I breathe one breath at a time. I inhale, I exhale. These spruces and cedars I cherish and know, the wind, the sweet scent of moist and dark soil — these are my small sense of enlightenment, my past life and present life and future life all in one moment.
Wohlleben chronicles what his own experience of managing a forest in the Eifel mountains in Germany has taught him about the astonishing language of trees and how trailblazing arboreal research from scientists around the world reveals “the role forests play in making our world the kind of place where we want to live.” As we’re only just beginning to understand nonhuman consciousnesses, what emerges from Wohlleben’s revelatory reframing of our oldest companions is an invitation to see anew what we have spent eons taking for granted and, in this act of seeing, to care more deeply about these remarkable beings that make life on this planet we call home not only infinitely more pleasurable, but possible at all.
But Wohlleben’s own career began at the opposite end of the caring spectrum. As a forester tasked with optimizing the forest’s output for the lumber industry, he self-admittedly “knew about as much about the hidden life of trees as a butcher knows about the emotional life of animals.” He experienced the consequence of what happens whenever we turn something alive, be it a creature or a work of art, into a commodity — the commercial focus of his job warped how he looked at trees.
Then, about twenty years ago, everything changed when he began organizing survival training and log-cabin tours for tourists in his forest. As they marveled at the majestic trees, the enchanted curiosity of their gaze reawakened his own and his childhood love of nature was rekindled. Around the same time, scientists began conducting research in his forest. Soon, every day became colored with wonderment and the thrill of discovery — no longer able to see trees as a currency, he instead saw them as the priceless living wonders that they are. He recounts:
Life as a forester became exciting once again. Every day in the forest was a day of discovery. This led me to unusual ways of managing the forest. When you know that trees experience pain and have memories and that tree parents live together with their children, then you can no longer just chop them down and disrupt their lives with large machines.
The revelation came to him in flashes, the most eye-opening of which happened on one of his regular walks through a reserve of old beech tree in his forest. Passing by a patch of odd mossy stones he had seen many times before, he was suddenly seized with a new awareness of their strangeness. When he bent down to examine them, he made an astonishing discovery:
The stones were an unusual shape: they were gently curved with hollowed-out areas. Carefully, I lifted the moss on one of the stones. What I found underneath was tree bark. So, these were not stones, after all, but old wood. I was surprised at how hard the “stone” was, because it usually takes only a few years for beechwood lying on damp ground to decompose. But what surprised me most was that I couldn’t lift the wood. It was obviously attached to the ground in some way. I took out my pocketknife and carefully scraped away some of the bark until I got down to a greenish layer. Green? This color is found only in chlorophyll, which makes new leaves green; reserves of chlorophyll are also stored in the trunks of living trees. That could mean only one thing: this piece of wood was still alive! I suddenly noticed that the remaining “stones” formed a distinct pattern: they were arranged in a circle with a diameter of about 5 feet. What I had stumbled upon were the gnarled remains of an enormous ancient tree stump. All that was left were vestiges of the outermost edge. The interior had completely rotted into humus long ago — a clear indication that the tree must have been felled at least four or five hundred years earlier.
How can a tree cut down centuries ago could still be alive? Without leaves, a tree is unable to perform photosynthesis, which is how it converts sunlight into sugar for sustenance. The ancient tree was clearly receiving nutrients in some other way — for hundreds of years.
Beneath the mystery lay a fascinating frontier of scientific research, which would eventually reveal that this tree was not unique in its assisted living. Neighboring trees, scientists found, help each other through their root systems — either directly, by intertwining their roots, or indirectly, by growing fungal networks around the roots that serve as a sort of extended nervous system connecting separate trees. If this weren’t remarkable enough, these arboreal mutualities are even more complex — trees appear able to distinguish their own roots from those of other species and even of their own relatives.
Wohlleben ponders this astonishing sociality of trees, abounding with wisdom about what makes strong human communities and societies:
Why are trees such social beings? Why do they share food with their own species and sometimes even go so far as to nourish their competitors? The reasons are the same as for human communities: there are advantages to working together. A tree is not a forest. On its own, a tree cannot establish a consistent local climate. It is at the mercy of wind and weather. But together, many trees create an ecosystem that moderates extremes of heat and cold, stores a great deal of water, and generates a great deal of humidity. And in this protected environment, trees can live to be very old. To get to this point, the community must remain intact no matter what. If every tree were looking out only for itself, then quite a few of them would never reach old age. Regular fatalities would result in many large gaps in the tree canopy, which would make it easier for storms to get inside the forest and uproot more trees. The heat of summer would reach the forest floor and dry it out. Every tree would suffer.
Every tree, therefore, is valuable to the community and worth keeping around for as long as possible. And that is why even sick individuals are supported and nourished until they recover. Next time, perhaps it will be the other way round, and the supporting tree might be the one in need of assistance.
A tree can be only as strong as the forest that surrounds it.
One can’t help but wonder whether trees are so much better equipped at this mutual care than we are because of the different time-scales on which our respective existences play out. Is some of our inability to see this bigger picture of shared sustenance in human communities a function of our biological short-sightedness? Are organisms who live on different time scales better able to act in accordance with this grander scheme of things in a universe that is deeply interconnected?
To be sure, even trees are discriminating in their kinship, which they extend in varying degrees. Wohlleben explains:
Every tree is a member of this community, but there are different levels of membership. For example, most stumps rot away into humus and disappear within a couple of hundred years (which is not very long for a tree). Only a few individuals are kept alive over the centuries… What’s the difference? Do tree societies have second-class citizens just like human societies? It seems they do, though the idea of “class” doesn’t quite fit. It is rather the degree of connection — or maybe even affection — that decides how helpful a tree’s colleagues will be.
These relationships, Wohlleben points out, are encoded in the forest canopy and visible to anyone who simply looks up:
The average tree grows its branches out until it encounters the branch tips of a neighboring tree of the same height. It doesn’t grow any wider because the air and better light in this space are already taken. However, it heavily reinforces the branches it has extended, so you get the impression that there’s quite a shoving match going on up there. But a pair of true friends is careful right from the outset not to grow overly thick branches in each other’s direction. The trees don’t want to take anything away from each other, and so they develop sturdy branches only at the outer edges of their crowns, that is to say, only in the direction of “non-friends.” Such partners are often so tightly connected at the roots that sometimes they even die together.
But trees don’t interact with one another in isolation from the rest of the ecosystem. The substance of their communication, in fact, is often about and even to other species. Wohlleben describes their particularly remarkable olfactory warning system:
Four decades ago, scientists noticed something on the African savannah. The giraffes there were feeding on umbrella thorn acacias, and the trees didn’t like this one bit. It took the acacias mere minutes to start pumping toxic substances into their leaves to rid themselves of the large herbivores. The giraffes got the message and moved on to other trees in the vicinity. But did they move on to trees close by? No, for the time being, they walked right by a few trees and resumed their meal only when they had moved about 100 yards away.
The reason for this behavior is astonishing. The acacia trees that were being eaten gave off a warning gas (specifically, ethylene) that signaled to neighboring trees of the same species that a crisis was at hand. Right away, all the forewarned trees also pumped toxins into their leaves to prepare themselves. The giraffes were wise to this game and therefore moved farther away to a part of the savannah where they could find trees that were oblivious to what was going on. Or else they moved upwind. For the scent messages are carried to nearby trees on the breeze, and if the animals walked upwind, they could find acacias close by that had no idea the giraffes were there.
Because trees operate on time scales dramatically more extended than our own, they operate far more slowly than we do — their electrical impulses crawl at the speed of a third of an inch per minute. Wohlleben writes:
Beeches, spruce, and oaks all register pain as soon as some creature starts nibbling on them. When a caterpillar takes a hearty bite out of a leaf, the tissue around the site of the damage changes. In addition, the leaf tissue sends out electrical signals, just as human tissue does when it is hurt. However, the signal is not transmitted in milliseconds, as human signals are; instead, the plant signal travels at the slow speed of a third of an inch per minute. Accordingly, it takes an hour or so before defensive compounds reach the leaves to spoil the pest’s meal. Trees live their lives in the really slow lane, even when they are in danger. But this slow tempo doesn’t mean that a tree is not on top of what is happening in different parts of its structure. If the roots find themselves in trouble, this information is broadcast throughout the tree, which can trigger the leaves to release scent compounds. And not just any old scent compounds, but compounds that are specifically formulated for the task at hand.
The upside of this incapacity for speed is that there is no need for blanket alarmism — the recompense of trees’ inherent slowness is an extreme precision of signal. In addition to smell, they also use taste — each species produces a different kind of “saliva,” which can be infused with different pheromones targeted at warding off a specific predator.
Wohlleben illustrates the centrality of trees in Earth’s ecosystem with a story about Yellowstone National Park that demonstrates “how our appreciation for trees affects the way we interact with the world around us”:
It all starts with the wolves. Wolves disappeared from Yellowstone, the world’s first national park, in the 1920s. When they left, the entire ecosystem changed. Elk herds in the park increased their numbers and began to make quite a meal of the aspens, willows, and cottonwoods that lined the streams. Vegetation declined and animals that depended on the trees left. The wolves were absent for seventy years. When they returned, the elks’ languorous browsing days were over. As the wolf packs kept the herds on the move, browsing diminished, and the trees sprang back. The roots of cottonwoods and willows once again stabilized stream banks and slowed the flow of water. This, in turn, created space for animals such as beavers to return. These industrious builders could now find the materials they needed to construct their lodges and raise their families. The animals that depended on the riparian meadows came back, as well. The wolves turned out to be better stewards of the land than people, creating conditions that allowed the trees to grow and exert their influence on the landscape.
This interconnectedness isn’t limited to regional ecosystems. Wohlleben cites the work of Japanese marine chemist Katsuhiko Matsunaga, who discovered that trees falling into a river can change the acidity of the water and thus stimulate the growth of plankton — the elemental and most significant building block of the entire food chain, on which our own sustenance depends.