The power of trees How ancient forests can save us if we let them

Peter Wohlleben, 1964-

Book - 2023

"From the international bestselling author of The Hidden Life of Trees. An illuminating manifesto on ancient forests: how they adapt to climate change by passing their wisdom through generations, and why our future lies in protecting them. In his beloved book The Hidden Life of Trees, Peter Wohlleben revealed astonishing discoveries about the social networks of trees and how they communicate. Now, in The Power of Trees, he turns to their future, with a searing critique of forestry management, tree planting, and the exploitation of old growth forests. As human-caused climate change devastates the planet, forests play a critical role in keeping it habitable. While politicians and business leaders would have us believe that cutting down f...orests can be offset by mass tree planting, Wohlleben offers a warning: many tree planting campaigns lead to ecological disaster. Not only are these trees more susceptible to disease, flooding, fires, and landslides, we need to understand that forests are more than simply a collection of trees. Instead, they are ecosystems that consist of thousands of species, from animals to fungi and bacteria. The way to save trees, and ourselves? Step aside and let forests--which are naturally better equipped to face environmental challenges--heal themselves. With the warmth and wonder familiar to readers from his previous books, Wohlleben also shares emerging scientific research about how forests shape climates both locally and across continents; that trees adapt to changing environmental conditions through passing knowledge down to their offspring; and how old growth may in fact have the most survival strategies for climate change. At the heart of The Power of Trees lies Wohlleben's passionate plea: that our survival is dependent on trusting ancient forests, and allowing them to thrive."--

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2nd Floor 577.3/Wohlleben Checked In
Vancouver ; Berkeley ; London : David Suzuki Institute 2023.
Main Author
Peter Wohlleben, 1964- (author)
Other Authors
Jane Billinghurst, 1958- (translator)
Item Description
Translation of: Der lange Atem der Bäume : wie Bäume lernen, mit dem Klimawandel umzugehen - und warum der Wald uns retten wird, wenn wir es zulassen. Munich : Ludwig Verlag, ©2021.
Physical Description
271 pages ; 23 cm
Includes bibliographical references (pages 246-261) and index.
  • Introduction
  • Part I. The Wisdom of Trees
  • 1. When Trees Make Mistakes
  • 2. A Thousand Years of Learning
  • 3. Seeds of Wisdom
  • 4. Filling Up in Winter
  • 5. Red Flags for Aphids
  • 6. Early Risers and Late Sleepers
  • 7. Forest Air-Conditioning
  • 8. When Rain Falls in China
  • 9. Take Care and Stand Back
  • 10. Underrated All-Rounders
  • Part II. When Forestry Fails
  • 11. Backed Up Against a Wall
  • 12. Butchery in the Beech Forest
  • 13. Germany's Search for the Supertree
  • 14. Good Intentions, Poor Outcomes
  • 15. The New Bark Beetle?
  • 16. Wolves as Climate Guardians
  • 17. Is Wood as Eco-Friendly as We Think?
  • 18. It's Time to Pay Up
  • 19. The Toilet Paper Argument
  • 20. More Money, Less Forest
  • 21. The Ivory Tower Wobbles
  • 22. What's on Your Plate?
  • Part III. Forests of the Future
  • 23. Every Tree Counts
  • 24. Does Everyone Have to Be On Board?
  • 25. A Breath of Fresh Air
  • 26. The Forest Will Return
  • Afterword: Accepting Ignorance and Treading Carefully in the Forest
  • Acknowledgments
  • Notes
  • Index
Review by Booklist Review

Forester and bestselling environmental writer Wohlleben (Forest Walking, 2022) draws largely on observations of his home territory in Germany in this thoughtful look at how trees learn and adapt to difficult climate circumstances. As he explains, trees do not "stand there and suffer," enduring the effects of global warming as "creatures rooted in their environments." Instead, they react to the conditions that affect them. Ranging through a variety of tree species, he chronicles what that adaptability looks like and how much the luxury of time is needed for success. Readers will see the lesson here. Giving the environment the chance it needs to heal is crucial. The problem, as Wohlleben makes clear in chapters highlighting things like the pandemic frenzy for toilet paper and the global appetite for beef, is that the forest is often the last recipient of humanity's benevolence. The author is in his element here as a gentle purveyor of knowledge that provides a new perspective on a crucially important topic. His many fans will be enthused, and new readers will appreciate entering Wohlleben's evocative world.

From Booklist, Copyright (c) American Library Association. Used with permission.
Review by Publisher's Weekly Review

Forester Wohlleben (The Heartbeat of Trees) offers a pointed critique of harmful forestry practices and urges humans to let trees heal themselves. Excoriating government bureaucrats in his native Germany for their misguided attempts to help struggling forests, he describes how state-approved initiatives to introduce nonnative tree species better suited to warming temperatures than indigenous varieties have wreaked havoc on those ecosystems and devastated local animal and insect populations. Instead, Wohlleben suggests it's usually best "to step aside and allow natural reforestation to take its course," excepting for such instances as planting on former farmland "where there are no old trees nearby that could seed themselves." As evidence, the author highlights trees' remarkable capacity for adaptation and observes how, near his forest academy in west Germany, trees on south-facing slopes fared better during a 2020 drought than those on north-facing slopes because the former had "learned to ration water" from enduring longer, hotter periods of direct sunlight. The criticism of German forestry practices will be of limited interest to U.S. audiences, but the insights into trees' surprising abilities captivates (Wohlleben contends that pedunculate and sessile oaks, once thought to be distinct, are likely a single species capable of changing the appearance of its leaves depending on the climate). Nature lovers should take note. (May)

(c) Copyright PWxyz, LLC. All rights reserved
Review by Kirkus Book Review

The author of The Hidden Life of Trees returns with a book that shows how trees help each other and us. A highly experienced German forest manager with keen insight, Wohlleben persuasively describes the beauty, complexity, and resilience of natural forests versus the planted monospecies "plantations" dominating Germany's arboreal landscapes. Illustrating for lay readers the work of Suzanne Simard, the pioneering ecologist who demonstrated the remarkable ability of trees to communicate via networks of roots and fungi, Wohlleben shows us how trees thrive in diverse, untamed communities--and how vulnerable they become when isolated from other trees. "Trees…are not life-forms that stand there and suffer as human activity changes the global climate," he writes. "Rather, they are creatures rooted in their environments that react when conditions threaten to get out of control." The author is less persuasive in his claim forests cannot be "managed" to thrive while being culled for considerable amounts of wood (the most sustainable large-scale building material, as it can sequester carbon while steel and concrete emit it). Wohlleben contends that it is "impossible to extract raw materials in a way that benefits nature"; that German forest-industry politics would get in the way even if it were possible; that wood doesn't last long, anyway. However, his sourcing is thin, as it has occasionally been in earlier books. Many agree with Wohlleben that trees are a key weapon in the war against climate change, but many also contend that wood can be safely drafted into the war--that humans, like trees, can collaborate with nature. Good introductory reading for those interested in the role of trees--and wood--in climate change. Copyright (c) Kirkus Reviews, used with permission.

Copyright (c) Kirkus Reviews, used with permission.

1. When Trees Make Mistakes In hot, dry summers, trees have big problems. They cannot escape to the shade, and they cannot take a sip of water to cool themselves down. Indeed, they cannot react quickly in any way. And because they're so slow, it's all the more important for them to choose the right coping strategy. But what is the right strategy and what happens when a tree makes a mistake? I had a ringside seat to observe this from the academy I established in Wershofen in the German state of Rhineland-Palatinate to educate people about forests and help support struggling forests around the world. One side of North Street is lined with horse chestnuts. In the dry summer of 2020, the horse chestnuts behaved much like many trees in Europe that year: their leaves began to take on the colors of fall in August, which is far sooner than normal. Horse chestnuts have been having a particularly challenging time in many parts of Europe for years. Shortly before 2000, horse-chestnut leaf miners advancing northward reached the trees in Wershofen. These small, light-brown moths are native to Greece and Macedonia, the horse chestnuts' original homeland. Up until the moths' arrival, like many other imported plants, the horse chestnuts in Wershofen had been leading charmed lives. Although the ecosystems in countries like Germany are not perfect for these trees--it really is a bit too cold for them this far north--nevertheless, our chestnuts settled in nicely. The parasites that plagued them back home had not yet made it to the trees' new location and being slightly colder in winter was a small price to pay for a life without leaf miners. Then, about forty years ago, things started to change. That was when the moths began to follow their prey north, and eventually they, too, arrived in Wershofen. Leaf miners do just as their name suggests: the caterpillars "mine" tunnels in leaves. The female moths lay their eggs on the surface of the leaves, and after they hatch, the caterpillars eat their way inside. Small brown, wavy lines show where the moth babies have been happily chowing down--happily, because living inside a leaf offers good protection from hungry birds. The mined sections of the leaves dry out, and the caterpillars continue to eat. As summer progresses, the foliage looks increasingly ragged, especially as the first round of egg laying is often followed by a second. The leaves on the trees along North Street were therefore already damaged when, after several hot days, the drought settled in. In a situation like this, chestnuts react just as all trees do: they shut down photosynthesis and wait. The trees have even less of an idea than we do of how long a dry period like this might last and therefore it makes sense for them not to panic right away. The trees' first response is to close the millions of tiny mouths, the stomata, located on the undersides of their leaves. Trees use these tiny mouths to breathe, just like we do, and, just like us, trees expel water vapor with every breath. The water vapor cools their surroundings as it evaporates, and the green giants actively manage this process to make hot summer days more bearable. When the roots signal all the moisture in the soil has been used up, the trees close these countless mouths. However, when the stomata are closed, photosynthesis stops because carbon dioxide is no longer entering the leaves. Without water and carbon dioxide, the trees can no longer use sunlight to produce sugar. At this point, the trees begin to consume the sugar reserves they were hoping to increase so they could survive their long winter sleep. Despite the shutdown, the trees continue to lose a minimal amount of moisture through their leaves, roots, and bark. If the drought continues, they now employ a second strategy: they discard some of their leaves. Like their fellow green giants, the chestnuts lose their leaves from top to bottom, and the first leaves to fall are those way up in the canopy, farthest from the roots. Trees expend a great deal of energy transporting water to their crowns, and because they can no longer stockpile sugar, they need to conserve energy. If dropping the topmost leaves doesn't do the trick, and if the rain still doesn't come, the trees continue to drop leaves gradually from the top down until finally, as early as August, they stand there with completely bare branches. In 2020, almost none of the beeches, oaks, or chestnuts around Wershofen had resorted to this final step. Only a few individuals had given up. Perhaps these trees were particularly anxious and wanted to play it safe. Or perhaps they were growing in especially dry spots. Whatever the reason, by August, the branches on these trees had no leaves left on them at all. The chestnuts in particular really couldn't afford to lose their leaves, as by summer they had already been weakened by leaf miners. Their leaves, covered in brown patches where the caterpillars had fed, were producing limited quantities of sugar, which meant the trees were starving. Next on the chestnuts' list of challenges was the elevation at which they were growing. North Street lies about 2,000 feet (600 meters) above sea level. The elevation and the harsh conditions in the Eifel, a low mountain range in central Germany, make for a short growing season and the window to produce sugar is tight. Trees need to produce enough not only to keep going day to day, but also to see them through their winter rest period and get them kick-started the following spring. In the Eifel, far from their original home, this was already a struggle for the chestnuts. And now they were dealing with the third dry summer in a row, during which every last drop of water in the soil had clearly been used up. Under normal circumstances, when trees encounter conditions like these, they simply advance their seasonal shutdown and drop their leaves in September--which is what the beeches in my forest typically do. Although the beeches look dead, they leaf out again in the spring and try to make up for time lost the previous year. Most of the chestnuts do this too. The anxious ones that dropped their leaves in August had definitely jumped the gun and employed this survival strategy too soon. On August 31, 2020, the weather gods had a change of heart. In a small area on the northern edge of the Eifel, clouds darkened the sky. It rained for hours, dumping about a quarter of an inch of rain (60 liters of water per square meter). This wasn't nearly enough to replenish water reserves in the drought-stricken soil, but the upper few inches got a bit damp, and I hoped it would be enough to give the trees some respite. The panicky chestnuts' reaction over the next few days took me by surprise and initially made no sense: they began to blossom. A tree that is already short on sugar shouldn't be putting energy into reproduction, especially since producing blossoms isn't going to pay off this late in the year. Even if the flowers were fertilized, there would be no time to develop seeds and fruit before the onset of winter. I was on my way back to the forest academy with a group of forest guides in training when they drew my attention to the chestnuts' behavior. We stopped to take a closer look, and it immediately became clear what was going on. Not only were the trees blooming, but they were also unfurling fresh new leaves. This solved the mystery. The chestnuts were starving. With fresh green growth on their branches, they could now stock up on sugar and fill their storage spaces. Clearly, the trees couldn't tell if they were growing only leaf buds or all the buds on their branches, including those that produce blossoms. And this was what we were witnessing. I made a short video with my cell phone and uploaded it to my social media page for discussion. I soon learned some chestnuts in other areas were resorting to the same strategy. An internet search revealed that a few horse chestnuts had unfurled fall blossoms in previous years. I wasn't totally convinced by the explanations that were being offered, which suggested the stress of climate change and attacks by leaf miners and fungi had brought the trees to the brink. The trees, then, were blossoming in the fall in a final, desperate effort to reproduce. On the face of it, the explanations sounded logical. However, they assumed trees are unable to differentiate between seasons. Blossoms in fall won't result in fruit because the few weeks that remain until winter are nowhere near long enough for fruit to ripen. Any tree that pursues such nonsensical behavior squanders energy and adds to its predicament. Scientists have known for decades that trees calibrate their behavior based on day length and temperature. In other words, they follow the seasons as accurately as we do--and they do so without needing a calendar. And this is where the next head-scratching assertion pops up: chestnuts are mixing up their seasons. The summer drought that interrupted their uptake of water and therefore their ability to photosynthesize had confused the trees so much that when the rain returned in fall, they thought it must be spring. This line of argument makes absolutely no sense because it ignores how evolution works. If horse chestnuts get so easily confused--after all, summer drought is a natural phenomenon that occurs at least every couple of decades--then how have they managed to survive for more than thirty million years? Any life-form that regularly engages in such nonsensical expenditures of energy would be too weak when faced with a crisis and would relinquish its hold on life. It's not confusion that drives the chestnuts' behavior, it's hunger. But once a tree has started something, it must see it through. It is not simply a case of unfurling new leaves (together with blossoms it has no use for). A series of events has been put into motion that must be followed through to the bitter end--and each step increases the tree's energy deficit. Growing leaves has taken energy the tree cannot afford to lose. It cashed in its last reserves when it spread its solar panels to manufacture sugar. It has also used up the buds intended for spring. The tree has opened its buds too soon, and if it is not to stand completely bare next year, it must now invest in new ones. And even that is not the end of it: as buds and leaves develop on new growth, the chestnuts must also grow new wood to carry them. Here's the bottom line: a tree that drops its leaves in summer and is then overtaken by hunger in fall must grow not only leaves (and blossoms it doesn't want or need) but also new wood and new buds. This effort is worthwhile only if the new leaves generate more sugar for the tree to store over winter than the tree spent producing all this new growth. Unfortunately, the march of the seasons is not in the frantic trees' favor. In September, the days are considerably shorter, which reduces the time the trees have to photosynthesize. Moreover, areas of low pressure usually move in a few weeks later, bringing with them a great deal of rain. Although this rain recharges the ground, it also obscures the sun. And if that were not enough, temperatures fall and the first overnight frosts make their presence felt. Excerpted from The Power of Trees: How Ancient Forests Can Save Us If We Let Them by Peter Wohlleben All rights reserved by the original copyright owners. Excerpts are provided for display purposes only and may not be reproduced, reprinted or distributed without the written permission of the publisher.