Conservancy Book Review 3
The Hidden Life of Trees: What They Feel, How They Communicate
by Peter Wohlleben
Submitted by Carey Benham
As a devoted nature lover on Kiawah Island, I never imagined a book about trees could be so surprising, so wondrous and even magical. The author, Peter Wohlleben, spent over 20 years working for the forestry commission in Germany and now devotes his work to the study of trees and the preservation of forests. In this book, he describes in a detailed, clear, entertaining, and often emotional way, the social lives of trees (particularly those which make up forests) and enables us to comprehend the crucial role forests play in our world.
Wohlleben’s main message is that trees are social living entities or “beings” and actually share many basic characteristics of humans. Yes, it sounds perfectly outlandish at first, but very logical after Wohlleben’s wonderfully deep explanations. He refers often to the magnificent forests of Central Europe, filled with oaks and beeches. We learn of the trees’ interconnectedness with those of their own species through their complex root systems which, with the help of fungal networks, are able to nourish each other and help neighbors in times of need, much like ant colonies. The communication network relies on electrical impulses traveling by nerve cells at the tips of the root systems. The fungi and root systems operate like fiber-optic Internet cables, transmitting signals from one tree to the next, exchanging news about insects, drought, and other dangers.
The social life of trees seems even more incredulous when we learn that mother trees take special care of their offspring by nourishing them through their root systems and also by managing their growth. Scientists have determined that slow growth for a young tree is extremely important if the tree is to live a very long time. What is old for a tree is way beyond the 120 years when most trees are felled for one reason or another. The mother works to make sure their “children” grow slowly (because they have plenty of time to grow up!) so that they will become more flexible, stronger and resistant to damage or to breaking in storms. To retard their offspring’s growth, the mother trees use their huge crowns of leaves to shade their little ones, depriving them of light, so that the small trees can only photosynthesize just enough to grow very slowly and to keep from dying. Sounds rather harsh – but it works!
The potential age of trees can actually be astounding, but as Wohlleben writes, many conditions threaten their health and length of life: predators, disease, competition from other tree species, damaging storms, and soil erosion. As you read this book, look around at our beautiful live oaks all over Kiawah Island and in the Lowcountry. Their average lifespan is 300 years, but in the right conditions, it’s possible for them to age to 1000 years! It’s estimated that Angel Oak on Johns Island is from 400 to 500 years old.
During this unusual year, we all have missed the ability to be close to others, to give each other a hug or even a handshake. Just as humans need friends for contact and support so trees physically lean on each other for support and stability. When one tree dies or is felled in a natural forest it causes a dramatic consequence. A gap opens up amidst the snuggling trees which had been leaning on each other, and they suddenly find themselves wobbly and unsupported. It can take quite a long time – from 3 to 10 years – for them to really stabilize and live firmly rooted. Social connectedness among trees includes the concept of actual friendship! A tree’s limbs naturally extend outward during a tree’s growth in a forest canopy. When the limbs of one tree encounter those of another tree of the same height, its limbs thicken in order to establish and reinforce themselves in competition with the other tree. But a pair of “friend” trees do not reinforce or thicken their limbs – they don’t want to take light or anything else away from each other. Trees like this are often connected at their roots and might even die together.
Attributing human characteristics to trees may seem somewhat farfetched but Wohlleben finds that doing so is very important. It makes us cognizant of the extremely sensitive, intricate and miraculous nature of plant and tree systems. It gives us empathy – encouraging us to accept and care that more is going on in trees than just drinking up water and producing leaves! According to the author, trees breathe, smell, taste, and feel pain among many other extraordinary life processes. And if you think this sounds over-the-top, bear with me and read a few examples and explanations:
Breathe: The “lungs” of trees are their leaves (or needles if coniferous), which have tiny slits (mouths) on their undersides, through which they inhale carbon dioxide and exhale oxygen.
Smell: Research from 40 years ago showed that the leaves of acacia trees in Africa gave off a toxic gas (ethylene) after giraffes bit into and nibbled on their leaves, causing the giraffes to move on. The gas travelled to other acacia trees which picked up the scent and then pumped the same kind of toxin into their own leaves to ward off the giraffes.
Taste: Trees can identify the saliva of different damaging insects (their only means would be by “taste”) and can match the saliva to the predator so exactly that the trees release pheromones, which call upon certain predators to attack the damaging insect.
Pain: Wohlleben sprinkles many illustrations of this throughout the book: micro-tears from overbending, caterpillar bites on its leaves…there are all sorts of ways that a tree tries to repair itself after painful damage. One of his most interesting suggestions in the book related more to extreme thirst in trees than to pain – but to me they are similar. When trees are really thirsty, they begin to “scream” at ultrasonic levels – caused by vibrations in their trunk occurring when water flow is interrupted. Wohlleben reminds us that we know how sounds are produced in humans: by the passage of air down the windpipe causing our vocal cords to vibrate, which is similar to what is happening in the tree trunks. He posits that the trees “might be screaming out a dire warning to their colleagues that water levels are running low.”
Throughout the book, Wohlleben stresses the fact that trees do not like to be alone but with other trees, particularly with their own species. It’s been shown that isolated trees do not live as long as those that live in forests. They are most advantageous to each other and to the environment if they are part of a forest ecosystem which can create its own microclimate, moderate extremes of heat and cold, store water and generate humidity. We have a variety of trees on Kiawah: pine, oaks, some hickories, junipers, and palmettos. How does this diversity impact their survival?
Forests are superorganisms, capable of actually migrating by means of seed dispersal in reproduction, over very long periods of time. According to the author, this migration is happening in Central Europe now with the forests moving north, not only because of climate change but because of change from the last ice age to a warmer era. Trees that migrate can establish themselves when they find the right climate, soil and moisture levels fit for their species.
The benefits of forests are not just for trees but for humanity as well. The air is much cleaner in a forest because the leaf canopy of the trees acts as a giant filter, catching small particles like pollutants, pollen and dust. By taking a walk in a forest, it is possible that the trees help lower our blood pressure, increase our lung capacity and the elasticity of our arteries. On a grander scale, coastal forests can be seen as one huge water pump, their leaves releasing water into the air via transpiration which in turn creates clouds that travel inland to release rain. For inland areas which can be drought stricken, this is of course very beneficial, and is a wonderful example of the interplay between trees and weather.
This review is just the tip of the iceberg as far as the wonderful insights and valuable information contained in The Hidden Life of Trees. I heartedly recommend the book for your enjoyment and enlightenment. As the author wrote, “…only people who understand trees are capable of protecting them.”