As a European, I became exposed to, then fascinated by, ginkgo trees during my far away travels, and again recently, when these adorable living fossils became my neighbors. The fact that ginkgos dump all of their leaves overnight before the first frost hits the ground and that female ginkgo drop their “poops” so vehemently as to permeate the entire neighborhood with a sewage-like stench, was my first step to learning about these beautiful creatures. On my street, ginkgos rule, and owners, if they insist, have to plant their own, different tree variations in the back alleys of their houses. Both sides of the narrow main street are dominated by tall ginkgos that in one hundred years grew tall above the houses. They hover, transforming the street below into an intimate, cozy space, well protected from the outside world. Our street is a universe by itself, an awe-inspiring ginkgo universe of total silence. Not even birds sit on the branches of these sacred trees that go back to Jurassic times.
But everything that we usually learn about these trees is superficial; what we know is merely what we see. Until very recently, the whole history of tree knowledge was nothing but the collection of our impressions. Just look back, and browse a bit through the literature that has been published about trees. From the earliest times, we ascribed them souls, divine powers, and human faces. When trees made a sound, he said they talk. As, for example, in this recent book in which Joan Klostermann-Ketels photographed different “expressions” of trees, describing their striking resemblance to humans in the way they stretch, ache, bend, and break. “The photographs reveal and identify not only recognizable emotions in the branches and trunks but also the extent of what trees do for humanity, such as clean the air and shade homes and gardens. The images also speak to the spiritual grandeur of trees, encouraging a greater consciousness of the fundamentals of nature and humankind’s relationship to something greater than themselves,” she said. For Klostermann-Ketels, the trees have healing powers; they talk, we just have to learn how to listen.
Recently, however, science did go a step further. First of all, there is Richard Karban, whose study of trees focused on the communications among them and other plants. Two of these studies proved willow trees, poplars, and sugar maples warn each other about insect attacks. Karban observes:
The debate is no longer whether plants can sense one another’s biochemical messages — they can — but about why and how they do it. Most studies have taken place under controlled lab conditions, so one of the major open questions is to what extent plants use these signals in the wild. The answer could have big implications: Farmers might be able to adapt this chatter, tweaking food plants or agricultural practices so that crops defend themselves better against herbivores. More broadly, the possibility that plants share information raises intriguing questions about what counts as behavior and communication — and why organisms that compete with one another might also see fit to network their knowledge.
It is about time! Finally, we’ve started to focus on how trees communicate. Perhaps the reason why this has not happened earlier is that the trees live quietly, much slower in the pace of their communication, a speed not at all natural to our spinning human minds. In Sweden, I learned, there is a tree that is more than 9,500 years old. That’s 115 times longer than the average human lifetime! And thanks to more recent research, we now know that electrical impulses passing through the roots of trees move at the prolonged rate of one-third of an inch per second. And yet, one might ask, why do trees need electrical impulses if they have no brain or nerve tissue? The scientist answers that trees need to communicate and electrical pulses are one of their means of communication.
I mentioned the capacity of trees to smell and emanate chemicals in case of danger. Peter Wohlleben, a former forester, has treated trees as lumber for most of his life. He then changed his job, and arguably his perspective, and started to observe them. The result of his discoveries is the book “The Hidden Life of Trees,” which revolutionizes our knowledge of their kind. Some, perhaps envious, scientists complain that his book is too anthropomorphic. I find it fascinating, however, not only because of his discoveries concerning the life of trees, but also because it is devoid of the stereotypes of our understanding of them, these creatures that we pity for not being able to move, and envy for their long lives and wisdom. This is how Wohlleben describes his surprising discovery:
Years ago, I stumbled across a patch of strange-looking mossy stones in one of the preserves of old beech trees that grows in the forest I manage.
Casting my mind back I realized I had passed by them many times before without paying them any heed. But that day, I stopped and bent down to take a good look. The stones were an unusual shape: they were gently curved with hollowed-out areas. Carefully, I lifted the moss of 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 the 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!
The stump of a tree that was felled four hundred years ago still grabbing to life is an astonishing discovery. How is this possible? Wohlleben concluded that it must be getting assistance from neighboring trees, specifically their roots; the surrounding beaches were pumping sugar into the stump to keep it alive.
“Trees have friends, feel loneliness, scream with pain and communicate underground via the ‘wood wide web.’ Some act as parents and good neighbors. And they also have sex,” hints Wohlleben in an interview for the Guardian. In short, trees are extremely social, they care for each other, sometimes going so far as to nourish the stump of a felled tree just to keep it alive. Not all the stumps, perhaps just parents of the trees that are still standing and growing, or are in some other sense “related.” Biologists, ecologists, foresters, and naturalists increasingly argue that trees speak and that humans can learn to hear this language.
Recently, Quartz reported that “tree language is a totally obvious concept to ecologist Suzanne Simard, who has spent 30 years studying forests. In June 2016, she gave a Ted Talk (which now has nearly 2.5 million views), called “How Trees Talk to Each Other”’ explained the article. It went on:
Trees exchange chemicals with fungus, and send seeds—essentially information packets—with wind, birds, bats, and other visitors for delivery around the world. Simard specializes in the underground relationships of trees. Her research shows that below the earth are vast networks of roots working with fungi to move water, carbon, and nutrients among trees of all species. These complex, symbiotic networks mimic
human neural and social networks. They even have mother trees at various centers, managing information flow, and the interconnectedness helps a slew of live things fight disease and survive together.Simard argues that this exchange is communication, albeit in a language alien to us. And there’s a lesson to be learned from how forests relate, she says. There’s a lot of cooperation, rather than just competition,among and between species as was previously believed.
It is the wood-wide -web that we know very little, or anything, about. What does it mean, then, that the fungi operate like fiber-optic Internet cables, that their thin filaments penetrate the ground, weaving through it in almost unbelievable density? What is the significance of one teaspoon of forest soil containing many miles of these “hyphae,” and that over centuries a single fungus can cover many square miles and network an entire forest?
These are fantastical questions, rooted, so to speak, in our attempt to understand the natural world. So when I look at the almost-naked crowns of my ginkgo neighbors, I do not know what to expect next. Everything I read about them tells me that, genetically, they haven’t changed for millions of years. That they are living fossils that had moved from Asia back to Europe at the beginning of the 19th century when the Brits started to plant them to resolve problems of industrial pollution.
Ginkgos are still in fashion and trending in Asia. Apparently, there were a couple of ginkgos that survived the nuclear blast at Hiroshima. Legend? Maybe, too, the fact that Seoul owns 114,000 ginkgos, served by more than 400 sanitation workers whose duty it is to harvest the fruits before the female trees drop them to the ground, where they rot, emitting that wretched smell. Koreans, who knows why will never replace them.
In other countries, they try to avoid the problem of the stench by planting male ginkgos only, a considerable task as ginkgos reveal their sex just at the age of twenty. Or, we could say they become sexually mature at the same age as human beings. But ginkgos, like fishes, can occasionally switch gender. Still, in the short period of fostering my passion for these trees, I haven’t noticed any consistent research on the underground life of ginkgos. Ripe for the taking.