Updated: Dec 18, 2020
“The tree which moves some to tears of joy is in the eyes of others only a green thing which stands in the way.” - William Blake
Along the African Savannah on a wet and foggy day four decades ago, giraffes meandered along the tree lines, occasionally shaking their heads in the rain. They began feeding on umbrella thorn acacias, trees that produce many succulent leaves and pods that the giraffes adore. Suddenly, the animals stopped eating and jerked their heads up and down in quick succession, as though having eaten something bitter. They began walking away from their food source, only stopping to eat from branches one hundred yards away.
Make Them Eat Ethylene
Scientists observing the animals that day later discovered the acacias had pumped toxic substances into their leaves to rid themselves of the large animals. The giraffes didn’t like the caustic taste and moved to other safer sources in the vicinity. The acacia trees produced a warning gas (ethylene) that not only spited the animals but signaled to neighboring trees of the same species that danger was imminent.
Immediately, all the trees also pumped the ethylene into their leaves to prepare themselves. The giraffes were not deterred and moved to find trees that were too far away to get the warning message. Another option for them was to move upwind where the scent messages are not carried to nearby trees.
Our Silent Companions
Trees hold a majestic place as the world’s oldest living organisms. Since humans have occupied the earth, they have been our silent companions, pervading our most enduring stories. Author Hermann Hesse called them “the most penetrating of preachers.” As the science expands, it’s obvious trees have a lot to teach us about communication, connection, and even love. Theirs is a silent, complex language, and one that shares information via electrical impulses, taste, and smell.
Indigenous people living in the forests across the earth understood the trees; they knew that they communicated and could send chemicals into their leaves. They understood that if an oak tree tumbled into a river, that the water became acidic, encouraging plankton to flourish. As arboreal research from scientists around the world documents the role forests play in making our world a better place to exist, we’re only just beginning to understand arboreal consciousnesses. What the research shows is that trees experience pain, have memories, and that tree parents live together with their children. And they talk to each other.
“All the trees here, and in every forest that is not too damaged, are connected to each other through underground fungal networks. Trees share water and nutrients through the networks, and also use them to communicate. They send distress signals about drought and disease, for example, or insect attacks, and other trees alter their behavior when they receive these messages,” says Peter Wohlleben, a German forester and author. Because of his work in tree research, a broader audience is introduced to the field, and science better understands their behaviors. The latest arboreal studies, conducted at universities around the world, confirm what Wohlleben has long suspected from practically living in the forest - trees are conscious, social, deeply sophisticated, and even intelligent.
What Is Love To The Trees
In a mountainous forest in western Germany, Wohlleben slushes through thick fresh snow with enormous black boots. He stops at two large birch trees and points into their branches.
“These two are old friends,” he tells writer Richard Grant with the Smithsonian Magazine. “They are very considerate in sharing the sunlight, and their root systems are closely connected. In cases like this, when one dies, the other usually dies soon afterward, because they are dependent on each other.”
It was long assumed that trees just existed, struggling for sunlight and water along with all the other trees. Wohlleben proves the opposite is true. Trees of the same genus are communal and quite often form bonds with trees of other species, even an emotional connection. The evolution of forest trees shows them living in cooperative, symbiotic relationships, governed by communication and a joint intelligence analogous to an ant colony. And the real connections are occurring underground.
Mycorrhizal networks consist of minute, hairlike root tips that unite trees together with microscopic fungal filaments to form an underground network. These networks appear to exist as a conjoined association between trees and fungi, and it’s believed they share nutrients like water and food.
In this cooperative environment, the fungi consume part of the sugar that trees photosynthesize from sunlight. The sugar feeds the fungi, and they forage the soil for nutrients that are consumed by the trees. Every member of a forest is connected and works together to live.
The Love Between Beech Trees
Wohlleben explains the time he discovered a gigantic five-foot beech stump in this forest, and he surmised the tree’s demise as occurring 500 years ago. When he chiseled the surface with his knife, Wohlleben found something astounding. The wood was still green with chlorophyll. There was only one possibility; the neighboring trees kept it alive with nutrients through the expansive network. “When beeches do this, they remind me of elephants,” he told the Smithsonian. “They are reluctant to abandon their dead, especially when it’s a big, old, revered matriarch.”
When other “family” member trees are sick or dying, the other trees help nurture it back to life by the root and fungi system. When they need water, they share their own. Trees are social beings that never isolate from the ecosystem but keep a constant and broad connection to the environment they live in. They communicate to fungi, grass, and even birds.
Wohlleben and other scientists tell us trees can detect scents through their leaves, and they possess a sense of smell just like humans. They also have a sense of taste. For example, when certain trees are ambuscaded by leaf-eating caterpillars, they taste the caterpillar saliva, and release pheromones that invite parasitic wasps. The wasps lay their eggs in the caterpillars, and the wasp larvae eat the caterpillars from the inside. “Very unpleasant for the caterpillars,” says Wohlleben. “Very clever of the trees.”
So, a forest is not merely a forest. Neighboring trees assist each other through their root systems, by a complex system of reciprocities. If this is not incredible enough, these arboreal connections are even more complex. Trees seem to recognize their own roots from those of other species and even of their own relatives. So, like humans, a tree is only as strong as the forest that surrounds it. There is something to learn from that, and we should begin to listen.