Peter Wohlleben’s 2015 book The Hidden Life of Trees: What They Feel, How They Communicate—Discoveries from a Secret World explores what modern science has learned—and has yet to find out—about trees and forests. Wohlleben’s book was named a best seller by the New York Times, Washington Post, and Wall Street Journal and won the Indie Choice Award for Best Nonfiction Book of the Year. Wohlleben, who has decades of experience working as a professional forester in the Hummel region of Germany, has used his own expertise as well as recent scientific research to inform this book. The Hidden Life of Trees was originally published in German, and this SuperSummary study guide is based on the Kindle English translation by Jane Billinghurst, which was published by the David Suzuki Institute and Greystone Books.

Summary

Wohlleben begins The Hidden Life of Trees by exploring trees’ ability to form social networks. He credits Dr. Suzanne Simard for discovering that trees can communicate with each other because their root systems are connected by networks of beneficial fungi. These root and fungal networks are now referred to by scientists as the “wood wide web,” which trees can use to share water and nutrients with neighbor trees of the same species. The author explains that trees communicate through electrical, visual, and olfactory means, and examines how trees react to pests by releasing defensive compounds through their leaves.

Wohlleben then analyzes different reproductive strategies and discusses the particularities of wind pollination, as well as seed and nut production. He also examines how young trees grow and reports that, despite producing millions of seeds throughout its lifetime, each adult tree will only produce one tree offspring that survives to adulthood. Wohlleben confronts the perception that fast-growing young trees are healthier than slow growing ones and demonstrates that slow growth helps to ensure long term health. He also argues that young trees grow best in undisturbed forests where they can maintain root connections with their parent tree, which “mothers” them by providing them with nutrients and prevents them from growing too quickly.

In his middle chapters Wohlleben discusses the latest research on trees’ fungal networks, water transportation system, and aging processes. The author continues to use simple language and analogies to help the reader understand complex scientific concepts, and also frequently compares trees to people to demonstrate how they age. He then provides the reader with the big picture of forest life, explaining how soil came to exist and its mutually beneficial relationship with trees. Wohlleben helps the reader understand trees’ effect on the earth’s weather systems by explaining how connected forests can help move water from coastal regions to inland ecosystems.

Wohlleben then transitions to discussing the conditions trees need to thrive, and how human interference with natural systems can upset the balanced conditions and biodiversity necessary for a healthy forest. Wohlleben demonstrates the interconnected nature of the forest food and housing web by examining the lives of creatures such as the woodpecker, the beetle, and the beaver. He also explains how dead trees are as important to the forest ecosystem as living ones since dead trees provide a food source for one fifth of all plant and animal species on Earth.

Finally, Wohlleben describes how human activity has influenced forest health. He analyzes how people can both intentionally and unintentionally introduce invasive species including trees, plants, insects, fungi, and bacteria to foreign ecosystems, and how this can upset the ecosystem’s natural balance. He also educates the reader on how trees adapt to environmental changes through behavior changes and genetic variability.

He supports his argument for preserving old growth forests by pointing out that undisturbed forests are more resilient to invasive species, extreme weather, and climate change. Commercial forestry must also become more ethical, he argues, by allowing trees to live according to their instincts in forests disturbed as little as possible. Wohlleben ends by reiterating the global benefits of intact and old growth forests, and encourages the reader to view the forest with a sense of wonder and curiosity.