The Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from a Secret World
By Peter Wohlleben
251 pages, Greystone Books Ltd., Vancouver/Berkeley 2016
Originally published in Germany in 2015 as Das geheime Leben der Bäume
A conversation in the 2009 film Avatar distills a central theme about two conflicting relationships towards nature. In the film, the Na’vi are a race of sentient extraterrestrial humanoids who inhabit the lush jungle moon of Pandora and one of their sacred trees has just been bulldozed by mercenaries in search of a valuable mineral called unobtainium. Dr. Grace Augustine, the lead scientist played by Sigourney Weaver, tries to explain the Na’vi’s sacred relationship to the trees of Pandora to Parker Selfridge (apt last name), played by Giovanni Ribisi.
Dr. Grace Augustine: “Those trees were sacred to the Omaticaya in a way you can’t imagine.”
Selfridge: “You know what? You throw a stick in the air around here it falls on some sacred fern, for Christ’s sake!”
Dr. Augustine: “I’m not talking about pagan voodoo here—I’m talking about something REAL and measurable in the biology of the forest.”
Selfridge: “Which is *what* exactly?”
Dr. Augustine: “What we think we know is that there’s some kind of electrochemical communication between the roots of the trees. Like the synapses between neurons. Each tree has ten to the fourth connections to the trees around it, and there are ten to the twelfth trees on Pandora.”
Selfridge: “That’s a lot, I’m guessing.”
Dr. Augustine: “That’s more connections than the human brain. You get it? It’s a network—a global network. And the Na’vi can access it—they can upload and download data—memories—at sites like the one you just destroyed.”
Selfridge: [after a stunned pause] “What the HELL have you people been smoking out there?” [beginning to laugh] They’re just goddamn trees.”
Dr. Augustine: “You need to wake up, Parker. The wealth of this world isn’t in the ground—it’s all around us. The Na’vi know that, and they’re fighting to defend it. If you wanna share this world with them, *you* need to understand *them*.”
Dr. Augustine embodies the scientist who is awed by the complexity of nature and fights to protect it, while Selfridge is the epitome of corporate greed who sees nature only as valuable as the money that can be extracted from it. The conflict between these two drastically different attitudes towards nature are almost always at odds. (By now it is surely apparent which side of the issue I’m on.)
In the dialogue, Dr. Augustine attempts to explain the intricate relationship between the Na’vi and the trees and between the trees themselves. While we will likely never have the Na’vi’s ability to “upload and download” information with the trees and animals of our planet, the relationship between the trees themselves is already happening right here on Earth and has been happening for millions of years! The book The Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from A Secret World by Peter Wohlleben presents a view of trees similar to Dr. Augustine’s. Wohlleben’s experience as a forester in Germany has shown him that trees are social beings and forests form an interconnected social network. His treatment of the topic illuminates the dramas of the forest and has the potential to radically shift the common perception of trees as stagnant objects. Wohlleben also shows there may be a middle ground between the two attitudes represented by Dr. Augustine and Parker Selfridge. It seems the majority of people see trees as stagnant objects, but would not like to see them killed. This group knows they are alive, abstractly, but doesn’t quite connect with them as fellow living things on the same level as mammals, for example. No wonder it’s easier to us to empathize with other mammals like dogs, cats, cows, and pigs. In evolutionary terms, we are very similar. One of the main reasons it’s so hard for us humans to identify and sympathize with trees is because our evolutionary trajectories diverged very early on—about 1.547 billion years ago. Another reason is because trees live on a completely different time scale than humans. On average, deciduous trees in untouched forests live to be four hundred to five hundred years old, roughly five times the average lifespan of humans.
Trees are similar to humans in surprising ways. They are perfectly capable of distinguishing their own roots from the roots of other species and even from the roots of related individuals. They form friendships with their neighbors via root systems. The degree of connection (or maybe even affection) determines how helpful a tree’s peers will be. For example, some trees nourish the stump of a felled tree for centuries after it was cut down by feeding it sugars, water, and other nutrients, thus sustaining its life. Only some stumps in undisturbed forests are nourished in this way and they are likely the “mother tree” that was the parent of the trees in the forest nourishing it. Like humans, trees age too. Their bark gathers wrinkles over time, especially on the sides facing the sun because of the harsh ultraviolet rays.
Trees register pain as soon as a creature starts nibbling on them. When a caterpillar or beetle bites off a chunk of leaf, the tissue around the site of the damage changes. The leaf tissue sends out electrical signals, just as human tissue does when it is hurt. However, unlike humans, the signal travels at the slow rate of a third of an inch per minute. As a result of this slow pace, it can take an hour or so before defensive compounds are released into the leaves to spoil the pest’s meal. For example, about four decades ago scientists noticed peculiar giraffe behavior on the African savannah. The giraffes fed on the leaves of an acacia tree and soon moved on to other trees—but not any acacia trees nearby. They resumed their meal only when they had moved about 100 yards away. Scientists discovered this was because the acacia trees realized the giraffes were feeding on them and began releasing ethylene (the same gas fruit produces as it ripens) to signal to neighboring trees of the same species that a crisis was afoot. Right away, all the forewarned trees began pumping toxins into their leaves to prepare themselves for the giraffe onslaught.
Wohlleben’s book has taught me that trees and humans are more alike than different. We would be remiss if we didn’t give them the attention, appreciation, and respect they deserve. After all, they’ve been here a lot longer than we have.
Rating: 5 stars
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Photo credits: @judsongates on Instagram