Vancouver, Canada: Greystone Books, 2016. 260 pages. $24.95.
Forester-turned-bestseller isn’t a common author tagline in American letters, but career ranger Peter Wohlleben won popular readership in Germany with his 2015 title Das geheime Leben der Bäume. In a country where the forest is prized as a key character in the cultural narrative, public interest in arboreal mysteries was seeded long ago. What Jane Billinghurst’s English translation, along with eighteen other translations optioned globally, has the potential to spread is greater acknowledgment of old-growth forests’ importance, especially in light of recent climate negotiations and the way policy decisions will impact this and other complex ecosystems.
Part of the pleasure of The Hidden Life of Trees is glimpsing the world beyond the frame of a human lifetime. To give one perspective-altering example, Wohlleben points out that the modern logging industry generally cashes in on trees once they reach eighty to 120 years old. One might assume since the average human lifespan is shorter that these “ripe” trees are at least adults. In fact, they are more like an eight-year-old girl who has undergone puberty early due to hormones in commercial milk, except abundant sunlight quickens their growth spurt. In an ancient forest a thick canopy of “mother” trees deprives younger trees of sunlight as they grow. This “strict upbringing,” Wohlleben says, ensures their long-term well-being by giving ample time to first strengthen their cell walls to weather storms before growing taller. In such a protected environment, a beech measuring a mere three to seven feet in height might be eighty years old or older. At an age that would be considered near the end of a long human life, these trees are mere children to their two-hundred-year-old mothers, themselves equivalent, Wohlleben says, to forty human years. Using his estimate, I determine my beech tree age by dividing my years by five. Wohlleben does not suggest this calculation, but he does encourage readers throughout to relate to trees in terms they understand.
Scientists or readers wary of anthropomorphism may be put off by the interjection of the occasional “ouch!” used to give voice to tree experience. As trees do not have nerves, it seems suspect to exclaim that when a deer nibbles off bark, it “is not only really painful for trees but also life-threatening.” Wohlleben does not address this paradox directly, nor provide current research into plant sentience to bridge the gulf between animal and plant perception. Instead he assumes that readers will take at face value that plant responsiveness is becoming more evident all the time. “They are standing there,” he says, in the case of adolescent trees, “with their lanky trunks and small crowns, waiting for it to be their turn to grow.” He later cites research that certain trees hibernate to store sunlight, cast off their leaves to excrete waste, and summon insect predators to defend them against foragers, among other active replies to their environment. He is not a scientist, but he calls on scientific discoveries to increase our wonder that tree life is not passive as many have long thought.
Some degree of anthropomorphism may be inevitable when trying to comprehend other forms of life. Wohlleben uses it to make his descriptions more accessible:
In the spring, when water is shooting up through the trees, streaming up to the buds, and delivering delicious provisions, several species of woodpeckers called sapsuckers drill dotted lines of small holes in the thinner trunks or branches. The trees begin to bleed out of these wounds. Tree blood doesn’t look very dramatic—it looks a lot like water—however, the loss of this bodily fluid is as detrimental to the trees as it is to us. This fluid is what these sap-sucking woodpeckers are after, and they begin to lick it up.
Tree blood has been called a great band name, but it isn’t the vernacular of scientific articles. The liberties Wohlleben takes with this exacting discipline are a tradeoff to stimulate more lay respect for the canny community of a longstanding stand of trees.
Despite the clandestine aura of its titles and subtitles in this English version, The Hidden Life of Trees is a practical book. Readers who enjoy a campfire will learn that birch bark makes good kindling because it is saturated with oil as a chemical defense against browsers. “Pull off only the outermost layer so that you don’t harm the tree,” he advises. Elsewhere, he corrects an erroneous German saying that translates as “In a storm seek a beech, not an oak.” Beeches are just as likely to get struck by lightning, he explains, though their smooth bark isn’t as prone to show scars. What is more important to remember, he goes on, is that neither of these deciduous trees would likely generate a large forest fire if struck, since their wood doesn’t contain resins or oils. Though once dominant in central European forests, these native trees have primarily been replaced by monocultures of spruce and pines, which dry out in the summer, become flammable, and ignite, most often as a result not of lightning but of human activity.
Wohlleben follows in the Georgic tradition, without Virgil’s lyric. His descriptions can be lovely on occasion, but their primary intent is to instruct. His illustration of a sugar sprinkling of hoarfrost, for example, would not be complete without an explanation of what creates this phenomenon: “When below-freezing temperatures and foggy conditions occur together, fine drops of moisture immediately freeze whenever they touch a branch or a needle.” His relationship to trees is too pragmatic to revel in how they “sparkle as though they were in a fairy tale” without considering how they are also “groaning under the weight of the ice.” He knows too well how, with one weak spot in the wood, “a dry crack echoes through the forest like a gunshot, and the whole crown comes tumbling down.” This imagined scene could slip easily into Grimms’ Fairy Tales, and the Brothers did spend their formative years within some two hundred kilometers of the Hümmel forest preserve Wohlleben manages. His informative text has little else in common with their tales except that it may be morally instructive to learn that the villain threatening our planet’s oldest woods is homogenous expansion.