I have loved trees and felt a kinship with them from childhood. I vividly remember learning to identify a tree from its form and the shape of its leaves in the fifth grade and how pleasing these discoveries were. I began to draw trees and leaves then and felt so content deepening this kinship and trying to render their beauty. I especially liked the symmetry of the branches above the earth and the roots below, and always drew both.
So, the title of this book alone intrigued me. It’s true, the life of trees is hidden in several ways, and Peter Wohlleben’s desire is to unveil it and so to educate his readers.
The life of trees is hidden from human knowledge and understanding, partly because research has tended to focus on forestry and the needs of the lumber industry. Wohlleben began his professional life in this domain, and he shares some of his early misconceptions and mistakes. He even writes that lay people sometimes understand the need for change in forest management better than professionals. There is another reason that we have tended to know and understand the life of trees so little. As the author says near the end of his book, trees are so different from us – they have no brain, their rhythm is much, much slower than ours, their lives hundreds of years longer – that we tend to think of them as objects instead of living entities. I have read other authors writing on trees who also seem to feel that they have to justify their subject to a potentially indifferent public: Hope Jahren, Colin Tudge, whose earlier book on trees is subtitled “How They Live and Why They Matter”. While photosynthesis has been understood for a couple of centuries, it is the environmental movement that has given impetus to understanding how the entire system of a tree functions, and that necessarily involves the roots as well as the trunk and the crown.
It is in those roots that a vital part of the life process of trees is hidden in the literal sense. The chapters which explain how trees support each other through their root systems, how these systems offer wider support to forest life, and their interdependence with the mycelium network of fungi are some of the most revelatory. So are the discussions of trees’ rapport with water, both through air, by evaporation, and through branches and roots which help to maximize water retention in the forest floor. The process of water transport within the tree is one of several areas which is not yet fully understood, but the hypotheses are fascinating.
The most unexpected chapters revealed the multiplicity of life that makes homes in tree cavities – beetles, ants, fungi – and the ways that trees prepare for the harsh conditions of winter. They stock up on sugar and let go their leaves which can amount to 1,200 square yards of surface, like a boat taking in a huge sail, Wohlleben writes. This gives branches and even trunks much more flexibility in winter winds. Knowing this, I now see bare branches as a skilful way of meeting those winds rather than bereft of their beauty.
Peter Wohlleben has thirty years of experience in forestry, yet he writes in a conversational, unpretentious style, so that I feel a human being is speaking, not an expert. There is one aspect of his language that disturbs me though: he writes about trees in an anthropomorphic way, attributing many human characteristics to them. The subtitle of his book immediately suggests this of trees: “What They Feel, How They Communicate”. There are some obvious reasons for this kind of language. It is clear that Wohlleben wants to change his readers’ perceptions of trees and forests from objects to living systems. He also wants to hold interest in a subject about which many people know very little, and there is always danger of attention slipping with a relatively little-known subject. Some readers may feel that the language worked in exactly these ways and may appreciate it.
I feel that the author carries it too far though. Suggesting that roots send out “news bulletins” is a metaphor, of course. He doesn’t mean this kind of detail literally. But sometimes that becomes a weakness. It covers over the specifics of how a process actually works. In some cases, he uses these metaphors when there is clearly a gap in the scientific knowledge. But at other times, it becomes downright idiosyncratic. Speaking of beech seedlings “twiddling their thumbs” for two hundred years before they sprout is just one example.
The biggest problem with this kind of language is that it implies volition in trees. Yet the author himself says that they do not have a brain, and he raises the very question of how they “know” coming weather conditions and other phenomena – which research suggests more and more that they do somehow. Historically, a fundamental difference between the plant and animal worlds has been that an animal has an intention, however simple: to obtain food, to avoid pain, for example, and can move physically to accomplish that intention. More and more findings suggest that this difference is not nearly so simple, however. The point is important enough to be as clear as current scientific knowledge makes possible, but not to assume.
We do have to grant that Peter Wohlleben is not alone in attributing human characteristics to trees. His book includes 76 endnotes from prestigious publications such as MaxPlanckResearch and Nature. Many of the titles cited use language similar to his. “Mother” trees and “child” trees have apparently become common terminology. Let us hope that the terminology will gradually reveal more and more how the hidden life of trees contributes to the richness of our own rather than obscuring those contributions.
The Hidden Life of Trees, What They Feel, How They Communicate, Greystone Books, 2017, ISBN 978-1-77164-248-4 (cloth). 978-1-77164-249-1 (epub). 245 pages. With Note from Dr Suzanne Simard. Endnotes. Index.