Tree – such a short, simple word.
The same is true in languages worldwide: arbre (French), puu (Estonian & Finnish), fa (Hungarian), Tré (Icelandic), boom (Dutch), drzewo (Polish), árbol (Spanish), chan (Lakota) and mitig (Ojibwe).
Belying the one-syllable words we use for them, trees are some of the most long-lived and complex beings on earth. And despite the fact that we’ve given colorful names to the various species of trees, the names we know best are those interchangeable with the products we make from them – hardwood floors, oak tables, cedar chests, cherrywood banisters, pine boxes, redwood patios and teakwood boat decks.
But what do we really know about the way trees live and grow? What do we know of the amazing similarities and distinct differences among the 60,065 different species of trees growing on this planet?
As author Peter Wohlleben says in The Hidden Life of Trees, “Forests are not first and foremost lumber factories and warehouses for raw materials, and only secondarily complex habitats for thousands of species, which is the way modern forestry currently treats them.”
I can’t remember a time when I haven’t loved trees. Nothing makes me happier than walking among them, or sitting at the base of one of my favorites, letting it calm me, soothe me, open my eyes and my heart to its slow-moving life. Ever since I was a young man, when people scoffed at environmentally conscious people by labelling them ‘tree-huggers’ I would proudly proclaim to anyone listening, “You’re goddam right I am.”
While I’m baring my soul, I should confess that I have not read many science-based books about trees. Instead of reading dendrology (or xylology, the study of trees) I’ve pored through novels like Barkskins, Annie Proulx’s ambitious novel covering three centuries of immigrants and their descendants witnessing, participating in — and some trying to stop — the deforestation of the New World from one coast to the other.
In hindsight I was perhaps sidestepping the botany of trees waiting to learn from someone as romantically attached to them as I am. Someone who can make a case for the sentience of trees, who can attest to the science of their communication, to their family nurturing practices, to their individuality and cooperation and to their patience and their wisdom.
Peter Wohlleben, a forestry manager in Germany, is exactly the person I’ve been waiting to hear from.
Imagine, if you will, sitting among your favorite grove of trees. Think about the age of the trees towering over you, shading you from the summer sun. They seem grown up and mature, while most of them are in fact still in their adolescence. They become mature adults at age 60 or 80, and depending on the species, and the conditions of their habitat, they’re capable of thriving well past their 200th birthday. Many, centuries longer.
Methuselah, a Great Basin Bristlecone Pine in the White Mountains of California, is 4,852 years old. An olive tree in Greece, an alerce in the Andes Mountains (right), a cypress in Iran and dozens of Giant Sequoias in Northern California are all thousands of years old. Think of the history they’ve witnessed, the wars they’ve survived, the winters they’ve suffered, the droughts they’ve endured. Think of their glorious spring revivals.
Imagine being fifty years old and still growing, still adding height and mass every year, looking forward to the day when your parents let you grow all the way up to their height. When you were a sapling, they sheltered you from too much sunlight, not wanting you to grow up too fast, knowing you’d have a hard time surviving if you did. Instead, they intertwined their roots with yours, making sure you got enough food and water. They made sure you could secrete terpenes and phenols which ward off illness and pests. And when a deer or giraffe starts nibbling on you, they know you’ll be able to defend yourself — making your leaves taste bitter and nasty.
Your parents also introduced you to the network of friendly fungus in the neighborhood. There are plenty of bad fungi around, the kind that helps spread disease and rot wood. But the friendly kind, a vast network of underground fungus, can be a ‘wood wide web’ for entire forests, letting trees share water and nutrition and helping them communicate with each other.
Trees even have an early warning system, chemical signals they send through their roots to ‘talk’ to each other. But they can’t do it without the fungus that connects them beyond the reach of their roots. There is a forest in Oregon with several different species of trees all connected by a single fungus. Covering 2,000 acres, it’s the largest living organism on earth.
Trees also communicate through the air. An acacia tree, for example, will do two things when a giraffe starts munching on its high leaves. First it will send a bitter secretion into its leaves. Then it will excrete a type of pheromone into the air to warn the other acacia in the area. Once the giraffe encounters its first nasty bite, it knows from experience it will have to move far away from that grove to find trees that haven’t been warned.
There’s so much more in The Hidden Life of Trees, fascinating details about how trees procreate, how they’ll skip lean years and drop their seeds when they know they’ll have weather conducive to their progeny. Their ability to guzzle hundreds of gallons of rain water through their leaves, down their trunks and into their roots in one sustained downpour. The fact that some trees, from the same family, are smarter than others. Wohlleben also talks about the oxygen-rich air you’ll find in a forest during the day, but not at night, about trees’ need for sleep at night and about the vast differences between the lives of forest trees and ‘street kids’ stuck in cities.
But, before I regurgitate every titillating tree fact in the book, let’s turn our attention to the indispensability of trees.
In recent years, most people have become abundantly aware of how much we need trees to help us stave off climate change. But trees do far more to sustain our biosphere than just consume CO2. Granted, that is essential and trees do it very well – which is why I want to scream every time I think about the ongoing clear-cutting of the Amazon rainforest – but even if had we had the ability to reduce atmospheric CO2 without their help, earth could not remain habitable without trees.
Trees create climate. They still the wind, disinfect the air and help distribute water around the globe. Without trees, inland farms wouldn’t get the rain they need. Ocean storms are only capable of bringing rain about four hundred miles inland. Coastal forests grab that rain, sequester it and then respirate it back out into the atmosphere to generate inland rain storms.
And trees are the mothership of biodiversity. Up to 2,000 living organisms inhabit a single tree. They are key to earth’s eco-system. Even after they die they help support life, including the lives of their children.
But are trees sentient beings?
As Wohlleben points out, “We have this essentially arbitrary caste system for living beings.”
Because they don’t have brains, don’t move and don’t have big brown eyes, “We just see them as oxygen producers, as timber producers, as creators of shade.”
If we look instead at defining life by function and process, trees meet every standard of sentience. They learn. They store information. They communicate. And they react.
Picture again, if you will, your favorite grove of trees. Instead of walking in among them to enjoy the shade and the purified air, if you approached those trees with a chainsaw roaring, even if you just trimmed a branch with it, the tree you cut and all the trees around it will react. They will disperse their fear pheromones to warn their friends. And if you’re there long enough with your murder weapon, they will defend themselves. They will slow down their photosynthesis, and begin to draw their sap inward, readying the secretions that will help it clot or close wounds.
Frightened trees suffer. Wohlleben points out that in his German forests and in well-tended forests around the world, when a fallen tree needs to be removed, his forestry team will accomplish the task with hand saws and mules. They will try not to shock the rest of the forest. They’ll do everything they can not to compact the soil, disturb root systems or to scare away the mammals, birds and insects who make that forest their home.
Our planet was once home to over 6 trillion trees. Forests started growing on earth some 350 millions years ago. Seven million years ago humans came along and started cutting them down. Most of the damage has been in the last five hundred years. As of 2021, we’ve cut down nearly half of all the trees on earth.
Humans will have a future on earth only if we stop wiping out the best friends we have and devote ourselves to massive restoration of our forests. If we are to enjoy that future, it will be when we’ve evolved enough to see the interconnectedness of all life around us.
We need trees more than they need us. Yet look how much they do for us. Look how beautiful they are.
How can you not love them?
For more, check-out the interview with author/forester Peter Wohlleben:
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