For the past several years, I’ve been terrified of trees.
In the time I’ve lived outside Philadelphia, there have been two hurricanes that reached their fingers as far as the mid-Atlantic. Although both were downgraded to storms by the time they arrived, the heavy rain of the first loosened a tree that snapped a power line in front of my house. During the second storm, winds caused another tree to collapse onto a neighbor’s roof right above a room with a baby inside. I trembled and barely slept those nights, and kept my own kids within arm’s reach, ready for the moment I’d have to shield their bodies from the deadly crush of a downed tree.
The neighborhood child was safe, and we were lucky, but my fear of trees remained. No longer were trees merely a pretty backdrop, or the fantastic creatures I remembered from fairy tales and films. In stories like Lord of the Rings or even Marvel’s Guardians of the Galaxy, trees are shown to be empathetic, sentient beings, but I knew that in reality those big, dangerous wooden things couldn’t possibly have compassion.
Or could they?
A mild dendrophobe—the name given to people afraid of trees—I discovered Peter Wohlleben’s book The Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from a Secret World while browsing bestsellers and was instantly intrigued by the title. I read the blurb and then an article in The New York Times about the book, feeling curious yet apprehensive. Was this author arguing that trees actually feel?
I gave into that curiosity. A bestseller in Germany, the recent English translation of The Hidden Life of Trees has given me a radically new, and more positive, view of forests and plants. In it, German forester Wohlleben draws on his own observations and others’ research, new and old, to explain how trees are more like us than we’ve been led to believe. The unique aspect of this book is how Wohlleben frames tree behavior in ways people can relate to, using terms like “friendship” and “nursing.” Wohhleben’s writing makes it easy even for people without a science background to understand his research.
I’ve come away realizing that instead of mere objects of fear, trees are complex lifeforms with behavior strangely similar to our own human displays of seduction, vengeance, and compassion. Here are six habits of trees that shocked me.
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1. Trees Communicate
Trees talk to each other—across distances and in ways I hadn’t fathomed. Maybe they don’t literally speak like The Lord of the Rings‘ Ents or Guardians of the Galaxy‘s Groot, but they communicate with each other all the same. According to Wohlleben, they do this through roots and fungi. Tree roots of the same species are often intermingled, so much so that a scientist in a 1997 issue of Nature called this interconnectedness in forests the “wood wide web.” They’re also often connected by fungi, which allow trees to transmit not only nutrients, but chemical compounds and slow-moving electric impulses that warn others of danger. Trees also use smell to communicate with their fellows: when some species of trees are being eaten by animals, they release a gas that is picked up by trees within 100 yards; those trees, in turn, release a toxin into their leaves that makes them less tasty to predators.
2. Trees Can Taste
Insects, the bane of my existence, can also pose a danger to trees. Sometimes bugs can be beneficial; for instance, bees help some trees pollinate. But in other cases, insects can cause great damage to leaves and bark. Luckily, trees can often identify the exact insect licking their leaf. In addition to using a mechanism similar to scent to detect gas released by other plants, trees can sense an insect’s saliva on their leaves, a sense that Wohlleben describes as akin to taste. It can be useful to know thy enemy, and though trees lack eyes and ears like humans have, these senses allow them to determine the devil in their midst.
3. Trees Fight Back
In addition to releasing toxic substances into their leaves to defend against predators, trees have other tricks up their green sleeves for their foes. Wohlleben says that when elms and pines realize they’re being devoured by caterpillars, they expel pheromones that entice parasitic wasps. The wasps, like some creepy alien creature, then lay eggs inside the hungry caterpillars. When the bouncing baby wasps are born, they eat their way out of their hosts—which sounds like something that might happen in Aliens.
4. Trees Care for the Sick
Trees often act in caring, borderline altruistic ways with one another. With their roots intermeshed, trees are able to share water and nutrients with those of the same species—and they often do, even when a fellow tree is only a stump in the woods with no hope of recovery. Wohlleben has experienced this in German forests, where he observed trees that continued to live after being cut down, supported underground by nearby tree friends.
Between healthy trees, common fungi connecting them balances the distribution of nutrients so no one plant gets too little, or too much, water and sugar. Isolated trees can often grow quicker without this balanced distribution, but trees that grow close and support each other this way end up living longer lives.
5. Trees Parent
Trees especially care for the younglings they created. I was surprised to learn that despite some species releasing millions of seeds in a lifetime, on average each tree will only create a single tree to take its place. Parenting is important, even helicopter parenting, it seems: trees with offspring growing close to them not only connect to them through root systems, but grow crowns that restrict light to the young ones, which allows them to grow stronger before they sprout up, thus prolonging their life.
6. Trees Decide When to Mate
Trees have to make do without Tinder. They can’t be picky, and without legs or WiFi they’ve got to rely on wind and, occasionally, bees to spread their seeds. But some species can decide when they want to release their pollen. Unlike their piney friends, leafy deciduous trees don’t just put themselves out there every year. To avoid inbreeding, some species, like the spruce, have both male and female blossoms, but release the pollen from each a few days apart; others, like willows, have either female or male blossoms. This creates genetic diversity, and the beautiful, strong, amazing forests we see today.
I’m still a little nervous in windstorms, but The Hidden Life of Trees has made me less frightened and more compassionate. Learning more about trees has increased my curiosity and awareness of the plant life around me, and reminded me that nature is more than just a thing to be feared.