62 pages • 2 hours read
Peter WohllebenThe Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from a Secret World
Nonfiction | Book | Adult | Published in 2015A modern alternative to SparkNotes and CliffsNotes, SuperSummary offers high-quality Study Guides with detailed chapter summaries and analysis of major themes, characters, and more.
Chapters 13-16Chapter Summaries & Analyses
Chapter 13 Summary: “Specialists”
Once a nut or seed sprouts it is “bound to this little piece of earth for the rest of its life,” no matter how inappropriate the location (73). Challenging environments include dark, shady places, marshy conditions, or dry soil, or overly sunny and hot clearings. Wohlleben paints a picture of ideal growing conditions for most trees: crumbly, moist soil, sunny temperate summers, wet winters, few storms, and limited harmful insects or fungi. He points out, however, that such conditions are very rare, which is beneficial for biodiversity, since dominant trees like beeches would crowd out their neighbors if conditions were always perfect.
For example, the yew tree has evolved to have a “frugal” approach and live in the Beech tree’s understory. Because yews need so little light and take decades to develop their root systems, they have the potential to live to a thousand years old. Similarly, the hornbeam tree has also adapted to grow in the shade of larger trees and in the event of a drought might even outlast the larger beech trees.
The author discusses how most trees cannot survive in swamp conditions because the water deprives their roots of oxygen. Even if a sapling such as a birch, pine, spruce, or hornbeam starts to grow in these conditions its roots will rot in the wet soil, and it quickly dies off. Alders, however, have evolved to tolerate these mushy conditions. Wohlleben explains that their roots have air ducts which can transport oxygen, and their trunks have cork cells that function like “breathing holes” (78).
Chapter 14 Summary: “Tree or Not to Tree?”
The author begins Chapter 14 by questioning the scientific definition of a tree. He notes that there are “dwarf trees” called the Arctic shrubby birch in the Scandinavian region of Lapland that can take a century to grow only eight inches (79). Wohlleben observes that because of their small size they are not recognized as trees by scientists, even though the mountain ash and small beech trees are often similar sizes and are considered “real” trees.
He then discusses coppicing i.e., cutting a tree down and continually harvesting the new growth that regrows from its trunk. He observes that this technique can significantly extend the life of a tree, and notes that in this way very ancient trunks coexist with young shoots. He cites an example of a spruce in Sweden whose roots and trunk were over 9,000 years old yet were still producing new growth. He argues that these trees should be considered very old rather than new young trees since “the root is certainly a more decisive factor than what is growing above ground” (81).
Wohlleben then argues that a tree’s root system is the most likely place to be considered the tree’s “brain,” or where it stores information. He refers to the ancient roots and trunks that survive centuries of coppicing. He also cites new research on tree root systems that shows they are “full of surprises” (82). He notes that, like brains, root systems also have “chemical messengers,” “electrical impulses,” and responses to stimuli (82-83).
Wohlleben concludes his chapter by commenting on the controversy in the scientific community regarding tree sentience and intelligence. He reports that some scientists are keen to recognize their similarities with animals while others feel threatened by this softening of distinctions. He shares that he feels that people would regard trees with more respect if they understood their similarities to animals.
Chapter 15 Summary: “In the Realm of Darkness”
The author starts Chapter 15 by lamenting that, although it is such an essential aspect of life on earth, we know very little about the soil and its creatures. He shares that the soil accounts for over half of a forest’s biomass, but because its animals are microscopic people tend to be less interested and knowledgeable about it. Wohlleben writes: “There are more life forms in a handful of forest soil than there are people on the planet” (85). It is these creatures, and of course the fungi that Wohlleben has already mentioned, that make the soil a nourishing force that supports forest trees and plants.
Soil only came into existence after bacteria, fungi, and plants grew, died, and rotted into humus. Finally, trees evolved and occupied this new soil, and developed a symbiotic relationship with it. During these early stages of the soil’s existence it was easily eroded, and trees helped give it stability and protection from the weather. Humus could now build up undisturbed and not be washed away by storms. Here, Wohlleben adds an aside about the terrible effects of erosion to a forests’ health.
He then profiles a few of the tiny beings that live in the soil and provide essential services to the forest ecosystem. These include the beetle mite, which lives on decaying wood and animal parts, and the weevil, which feeds on leaf litter. While these tiny creatures usually only transport themselves as far as 30 feet in their whole lives, they can also be moved from forest to forest by birds who clean their feathers with soil in their dust baths.
Healthy, balanced soil is not easy to regenerate after it has been disturbed by humans. Even in replanted forests that are over a hundred years old the soil remains deprived and unbalanced compared to old growth forests. Wohlleben reiterates how crucial it is to protect these old growth forests, since they are increasingly rare and have precious soil life. Preserved forests can benefit communities in several ways, for example, through education, tourism, carbon emission offsetting, ecological burials, and more.
Chapter 16 Summary: “Carbon Dioxide Vacuums”
Wohlleben next discusses one of the forest’s main benefits to people: its ability to absorb and store carbon from the air. On average, over a tree’s lifetime, it can store about 22 tons of carbon in its trunk. In a healthy forest ecosystem, when the tree dies some of this carbon is released back into the atmosphere, but most of it “remains locked in the ecosystem forever” (93). However, when we log trees we release carbon back into the atmosphere—when we burn the wood its carbon is released, and the tree’s absence prompts layers of the soil’s humus to release carbon.
Fossil fuels are the compressed remains of ancient forests that grew 300 million years ago, and Wohlleben suggests that it would be beneficial to allow our current forests to go through the same natural cycles and efficiently store carbon just as ancient forests did. He confronts an old forestry myth that young trees grow quicker (and therefore store carbon more efficiently) than old trees. However, he cites a study that proved in fact the reverse is true, noting that if we want to effectively store carbon we must allow these older trees to live and not turn them into timber.
Chapters 13-16 Analysis
In these passages Wohlleben further describes the many factors that can influence a tree’s development in the interconnected forest ecosystem and how the trees themselves influence their environment as well. For example, he describes trees’ symbiotic relationship with soil, demonstrating how trees thrive in soil that contains an abundance of fungal and insect life. While soil provides trees with a place to root themselves and consume nutrients, Wohlleben also shows how trees benefit the soil, too. He explains that trees’ presence prevents soil erosion by protecting the soil from harsh winds and rainfall and also provides a constant mulch of rotting leaves and woody debris which—when decomposed by the appropriate bacteria, fungi, and insects—will become soil itself someday. By explaining these complex connections Wohlleben opens our eyes to the interdependence and multilateral nature of life in the forest.
In these passages Wohlleben builds on his theme of human interaction with the natural environment. He shows how human perception of the forest as a commodity—and the practice of clearcutting entire forests for lumber—can cause irreparable damage to these sites, even after they have been replanted. The author references numerous real-life examples to persuade the reader. For example, he discusses a replanted oak forest which, even after over a century since the original trees had been harvested, still did not have a healthy soil life or thriving trees. He uses this information to effectively convince the reader that there is still much to learn about how forests function and how to manage them responsibly and ecologically.
Wohlleben expands his argument about the importance of preserving old growth forests and letting some forests remain undisturbed by harmful human activity. He derides the idea that the forestry industry is “rejuvenating” forests by removing established trees and planting new seedlings in their place, since young trees cannot grow well without older trees nearby (97). He offers that there are ways to make profits from forests that do not involve logging. In the forest he manages, for example, people pay to be buried in the forest as an ecological alternative, and companies will pay foresters to maintain the forest to offset their carbon emissions. He cites other examples such as education, tourism, and even military purposes as evidence that it can greatly benefit communities to preserve forests. In doing so Wohlleben reveals his own opinions and politics which must have motivated him, at least in part, to write this book.
