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.
Themes
The Interconnected Forest Ecosystem
In The Hidden Life of Trees, Wohlleben manages to give readers a window into the specificity of tree functions and behavior while also painting a picture of their role as actors and receivers in the complex and interconnected forest ecosystem. Wohlleben begins his analysis of these connections by examining trees’ symbiotic relationship with fungi. While it certainly benefits trees to be able to communicate with one another and send nutrients to partner trees, the author also acknowledges that the fungi have their own agency as well. He explains that they “are pursuing their own agendas and appear to be very much in favor of conciliation and equitable distribution of information and resources” (10).
Beyond this “wood wide web,” Wohlleben educates the reader about the other forest creatures and what they give to (and take from) the trees. Remarkably, the author reports that about a fifth of all species on Earth, both plant and animal, rely on dead wood for sustenance. Their role in the ecosystem is to break down dead wood by eating and excreting it. Without these decomposers, there would be no new humus to build up the soil and all forest plant life would become impossible. Wohlleben also provides examples of larger forest animals and their interactions with the trees. He calls the woodpecker a “tree helper” due to its ability to quickly eradicate bark beetles from a tree (54).
However, Wohlleben also explains that woodpeckers specifically target healthy trees when they decide to make a new home, and in doing so, create an unhealable wound that will eventually kill the tree. He also credits beavers for helping forests thrive by managing waterways, even though their role as the “lumberjack of the animal world” also means that they regularly fell trees (110). By including these give and take examples, Wohlleben makes it clear that trees’ lives should never be interpreted in a vacuum, since they only exist because of the presence of other organisms, and trees’ existence guarantees livelihoods for many more.
Commercial Forests Versus Undisturbed Forests
Another theme that Wohlleben explores in The Hidden Life of Trees are the differences between undisturbed, old growth forests and forests that were planted by human hands for commercial purposes. These explanations help lay people understand how different forest conditions impact tree health, and how human activity can inhibit, rather than enhance, tree growth. This theme also supports the author’s argument that it is vital for tree health, and ultimately whole ecosystem and habitat health, for some forests to be left undisturbed. His theme also underpins his argument that a more natural approach to silviculture will make commercial forests more productive in the long term.
Wohlleben explains that in natural forests, young trees grow up in the shade of their parent tree, which slows their growth. This results in woody, airless cells with a strong resistance to both injuries and fungal invasions. By contrast, trees in commercial forests grow much faster, and therefore their wood contains more air, making them more susceptible to invasions by parasitic fungi and other threats to their health (123-24).
Another difference between planted and undisturbed trees is the health and connectivity of their root systems. Wohlleben’s analysis of the fungal networks trees rely on to communicate and share valuable resources is a cornerstone of his book. He makes it clear to the reader that only trees in undisturbed forests can develop extensive fungal networks since their roots are unharmed by human hands and machines. He claims that planted tree roots are so injured by intentional planting that, “they seem almost incapable of networking with one another” (5). He compares planted trees to “loners” and argues that they cannot thrive as they would in an old growth forest (5).
Wohlleben also notes that because machinery compacts soil in commercial forests, planted tree roots cannot become as strong and extensive as they would in looser, undisturbed soil. This, too, causes problems since trees with weak root systems are more likely to be damaged by storms. Wohlleben also laments that commercial forests are in more danger of soil erosion, as when they are clear cut thousands of tons of exposed soil can easily run off in the rain. He contrasts this with undisturbed forests which lose very little soil and can quickly build it up again with their leaf litter. By frequently comparing commercial forests with undisturbed forests, Wohlleben impresses upon the reader that trees’ special qualities and abilities are not guaranteed; they depend upon a great many other functions and organisms to remain intact. His inclusion of this theme persuades the reader to support his argument that human communities must protect old growth forests from logging and other human intrusions.
Tree Sentience
Wohlleben enthusiastically details the research plant scientists have produced that demonstrate the possibility of tree sentience and intelligence. As he develops this theme throughout his work, Wohlleben often adds in his own commentary or hypotheses and reminds readers that this is a new and exciting field of research. His inclusion of studies that suggest plants have some capacity to feel and learn also helps him argue that trees deserve to be perceived as more than mere objects. Instead, as he develops this theme he argues that trees should be respected as active beings that are closer to animals than things.
The author cites studies by Dr. Monica Gagliano to demonstrate that some plants have the ability to change their behavior over time. In her study on mimosa plants, Gagliano subjected their leaves to drops of water. Initially these plants reacted defensively to these droplets by curling up their leaves. However, over time they stopped reacting and allowed the water to fall on them. Wohlleben refers to another study by the same scientist which demonstrated that plants may be able to communicate through sound waves. Gagliano found that some plant roots “crackled” at a decibel too low for humans to hear, causing other seedlings to point their roots in the direction of these sounds (13). Wohlleben writes: “That means the grasses were registering this frequency, so it makes sense to say they ‘heard’ it” (13).
Wohlleben argues that trees are also sensitive to various stimuli and are capable of learning, writing, “you can see they are just by observing them” (47). For example, he claims that trees manage their water supply more frugally after they have experienced a drought. Expanding on this theme, Wohlleben also argues that since trees learn they must be able to store their information somewhere, and he supports the hypothesis that their root tips likely function as a kind of “brain” (83). The author refers to a Swiss study which found that tree roots reacted to stimuli in the soil and could communicate to their root tips to alter their course when needed. Wohlleben notes that these researchers believe that tree roots have brain-like structures on their tips.
Wohlleben’s inclusion of these studies supports his argument that, since trees can register stimuli and have a kind of awareness of the world around them, they should be regarded as much more than static objects. By providing the latest research on plant and tree learning and sensitivities, Wohlleben persuades the reader to consider the world from the perspective of a tree and open her mind to the possibility of a kind of vegetal sentience or intelligence. This theme also supports his argument that the forestry industry should embrace a new kind of silviculture that regards trees as feeling organisms and not commodified objects. As Wohlleben phrased it, “The real question is whether we help ourselves only to what we need from the forest ecosystem, and—analogous to our treatment of animals—whether we spare the trees unnecessary suffering when we do this” (242).
