580-589: Botany. The Hidden Life of Trees, by Peter Wohlleben

Early this year, I read The Overstory, by Richard Powers, a work of such stunning beauty that I had to keep putting it down to absorb its images. It was a novel about trees, really, although human characters slipped in and out of the lyrical descriptions of growth, life and decay on a grand scale. I read it with my phone handy so I could look up some of the unfamiliar species mentioned, and felt my heart rate slow as it aligned with the pace of life in the forest. I also learned some very interesting facts-- or at least I hoped they were facts. Powers alluded to a number of books in the novel and endnotes. On further research, The Hidden Life of Trees seemed like the one that might have inspired him most directly.

For one thing, The Hidden Life of Trees is itself almost a fictionalized account of forest biology. The tone is breezy in the extreme, and Wohlleben makes free with anthropomorphic references to trees' thoughts, emotions and plans. Trees are pictured as having etiquette, going to school and screaming. There are mother trees, street kids, and, most importantly, tree communities. The tone of the book has caused a lot of controversy and frustration, especially in Germany and France, and certainly made me question whether the author really was doing science.

But, as it turns out, the "controversy" around The Hidden Life of Trees could really just be better described as "irritation." No botanist is accusing Wohlleben of getting his facts wrong, just of presenting the information in a more informal way than is usual for science writing.

And there is a lot of information! Just about every tree behavior and aspect of the life of the forest that The Overstory depicts can be found in this book. All the astounding tales of tree symbiosis, cooperation, adaptation and interaction with other species are factually accurate. Trees do make sounds and emit electrical impulses. They do sense the passage of time and, of course, the vital changes in available light that will affect their ability to photosynthesize. They do form complex ecosystems with other beings, from mammals to microorganisms, and exhibit coordinated behaviors. And, most impressively, they really do live for hundreds, sometimes thousands of years. 

On a walk the other day, I saw this interesting example of a tree that Wohlleben would call a "street kid," a tree that has been planted in the narrow space between sidewalk and street and is having trouble finding any place to send its roots.  Roots need oxygen just like branches do, which is why most houseplants don't like to sit in water-- they need to breathe! Apparently the ground under streets and sidewalks is compacted by machinery before paving. Of course that makes it difficult to grow through and also eliminates air pockets. That's why roots end up in water and sewer line-- they are just trying to get some air!
This same tree also may be a good example of one that can reproduce from its root system. The root is covered with bright green sprouts with tiny leaves. Are they hoping to become trees, or do they think they are branches coming from the trunk? Maybe that is a distinction without a difference. It will be interesting to keep an eye on these little sprouts over the summer and see how big they get.

This delightful and easy read explained many other things I have observed in the garden and neighborhood. For example, some trees- oaks notoriously-- produce tannin in their leaves. That's the same thing that is in tea, that makes it bitter if you let it steep too long. It's also the reason that wine is often aged in oak-- the tannins are considered a flavor enhancer. It turns out that the tannin is a defense mechanism against fungus and enables oaks to survive wounds such as lightning strikes that would weaken and expose other kinds of trees. Unfortunately, it also is disagreeable to grasses and other herbaceous plants, which is why gardening under an oak tree is a constant argument with nature. Wohlleben is all about not arguing with nature, and would, I'm sure, advocate for cooperating instead, by choosing plants that love shade and don't mind tannin, like ferns and hostas.

Gardening also helped me relate to this book because trees are like smaller plants in many ways. Some of them can reproduce vegetatively, from their roots, as do dandelions or mint. All of them can reproduce from seed and have all kinds of different schemes for getting their seeds fertilized and distributed. Seeds might have wings to fly out from under the source tree's shadow (as dandelion seeds do), or they might come encased in delicious fruit (as berries are) so that some helpful animal will come along and carry them off to a new location-- perhaps digesting them first! Some trees just drop their seeds right under their own shade and let a battle for sunlight ensue, as do many flowers.

But one thing is true of every tree (and every flower): trees produce seeds in reckless excess. The quantity of maple keys or sharp little acorns or pinecones that one tree can drop on a lawn is truly astonishing and seems completely unnecessary for the survival of the species! Personally, I sweep maple keys off the porch, pull out maple tree sprouts from the flower beds, fill bags with pinecones for mulching, and hurt my feet on acorns that blanket the ground, wondering why trees have to be so messy. But the consistent observer of nature can learn that squirrels and other little animals appreciate this abundance, even if we don't. They are busy all year, snatching up the free lunch that falls at their feet.

In the wild, tree seeds face just as many obstacles to growth as they do when humans such as myself are actively trying to fight back the forest. Most are eaten by those little animals. Those that survive to sprout will usually be eaten by rabbits and other medium-sized animals. The deer will probably take care of the rest; they can eat a new tree up to three feet high. Even if a baby tree manages to survive long enough to come off the lunch menu for the animals of the forest, it will probably be getting very little light on the forest floor and will therefore be weak and susceptible to insects and fungus. It may very well die and return to the earth in the form of humus. Given all these obstacles, although a tree will produce more than a million seeds in its lifetime, often only ONE of them will live to maturity!

The abundance of seeds should not be a source of dismay to me, even when it's inconvenient. After all, like the squirrels, I owe my dinner to the fact that plants of all kinds are designed to produce far over and above the number of seeds needed to perpetuate their species. I eat corn, rice, wheat and oats-- those are all seeds. I eat meat and dairy products from animals that ate those seeds, too. I eat peaches and strawberries and grapes that contain seeds. Really, the whole animal kingdom is dependent on the fact that one plant can make many seeds, many more than it needs for its own purposes!

A wild forest supports a tremendous amount of life, both visible and invisible, and it also supports our souls. A deciduous forest is full of birdsong and the rustle of creatures great (deer) and small (chipmunks, frogs) moving through the brush and leaf litter on the forest floor. We enter and feel that we have found a place outside time and all that's merely human. Life of a completely foreign kind is busy all around us, as our breathing slows to match the scale of business that is conducted 100 feet in the air and unfolds over centuries. In a healthy, natural forest, the trees are at peace, because they are well-watered and their balanced ecology protects them from insect, fungus and animal attack. Leaves are eating sunlight, and mosses are eating dust, and the tree is breathing in my unwanted carbon dioxide and breathing out oxygen. The light in a forest is actually green under the canopy, since the leaves have absorbed every other color.

A pine forest has a deeper hush to it. The needles underfoot absorb footfalls and make the soil too acidic to support wild undergrowth. There is less food for birds and small mammals, and so, less rustling and less birdsong. The forest seems to soak up sound as it presides over a silence that has existed for longer than any human life. Furthermore, pine needles dispense phytoncides that disinfect the atmosphere and discourage mosquitos, while the breath of the trees and the shelter of their branches creates a microclimate that provides welcome respite from extreme weather. In any kind of well-balanced forest, our hearts find shalom.

All these processes are revealed in The Hidden Life of Trees. The knowledge and wisdom of this book will enrich your next walk in the woods and your relationship to our largest and oldest neighbors on this planet. Highly recommended!