The Social Life of Trees: How forests communicate through underground fungal networks

The “Wood Wide Web”; very few have heard of it, and yet, it is all around us. Under the soil we walk on and in the air we breathe! An invisible network that has spread its roots far and wide, connecting the trees around us to one another. But what exactly do the oak trees have to say? And how come their conversations went undetected for so long? German forester, Peter Wohlleben has some answers!

For many years, we believed that trees were a group of ruthless loners. They competed with one another for resources (water, nutrients, and sunlight). The winners were cutthroat: blocking out the sky and starving all other contenders of the light they oh-so needed for photosynthesis and life. The forest was a battleground, a prime example of “survival of the fittest”. Now, however, there is substantial scientific evidence which contradicts our past beliefs.

Wohlleben, who manages a forest nature reserve, was the first to write about these new discoveries. His book The Hidden Life of Trees: What They Feel, How They Communicate became a publishing sensation, hitting best-seller lists across the globe. A book that never would have been written, if not thanks to the insistence of his wife, Miriam. The book puts the scientific revolution into the spotlight, showcasing what latest scientific studies have confirmed: trees are far more intelligent than we thought.

Trees of the same species are now shown to be communal. Wohlleben refers to two beech trees within his forest as being “old friends”, “sharing sunlight [and having] root systems [that] are closely connected”. He adds that, “in cases like this, when one dies, the other usually dies soon afterward, because they are dependent on each other.”

Not only that, but studies also show that trees will form alliances with individuals of other species. The forest is a battleground no more, but instead its own little community; a society made up of friendships and alliances that has lasted, in some cases, for hundreds of years. These bonds have been maintained by a unique form of communication – not that dissimilar to the “hivemind” of an insect colony.

“Some are calling it the ‘Wood Wild Web’ says Wohlleben, “All the trees […] in every forest […] are connected to each other through underground fungal networks.” Scientists have nicknamed the symbiotic relationships between shroom and tree “mycorrhiza”. The mycorrhizal networks are made possible by the fungi’s hypha, the root-like structure of the organism that is collectively known as mycelium.

The fungi’s roots and the tree’s roots hold one another’s hands, forming a chain of links that stretches far and wide beneath the forest floor. Through this network, the trees can send messages to one another. They may warn other trees about insect attacks, disease, or drought. In response, those who have received the message can activate the necessary defence mechanisms to protect them from the possible threat. Not only that, but with the help of the mushrooms, the trees can share water and nutrients – not as cutthroat as we thought!

However, the fungi’s assistance comes at a cost, and if you wish to use the mycorrhizal network, you had better pay up. In the forest’s world, currency comes in the form of sugars. The mushrooms lack the ability to produce their own, unlike the trees. Whilst other shrooms may take to consuming organic material, becoming the decomposers of the woods, mycorrhizal fungi have a bit more class. In exchange for sharing messages, they receive sugar in return, and they drive a hard bargain, securing up to 30% of the sugars the tree makes.

Yet, a connection isn’t the only thing these mushrooms provide. After all, what would be appealing about the mycorrhiza to the introverted trees of the world? In exchange for sugars, the mycorrhizal fungi assist with the uptake of minerals, such as nitrogen and phosphorous. These nutrients are vital to sustaining life, making up key components of proteins and DNA which are needed for growth and cell repair. Mycorrhiza has the forest covered.

This network is a lifeline for so many trees in our forests. Saplings often struggle to get the light they need for photosynthesis, but they survive thanks to the big trees that share their nutrients. Nevertheless, this network isn’t the only way for trees to communicate. In fact, these plants can send messages through the air in the form of pheromones, which are then detected by the other trees’ leaves. Wohlleben notes that giraffes are aware of these conversations between the acacia trees they feed on and purposefully browse into the wind to sneak up on unsuspecting trees that have yet to put up their defences.

The research into the language of trees is only just beginning, but I’m excited to see where the conversation goes next!