photo by Vladislav Todorov

How Trees Communicate With Each Other

The idea of talking trees exists for a long, long time. Although in reality trees cannot communicate with us, they talk to each other pretty much all the time. How do they do it? For that answer, we need to delve in the life of a forest and see what’s going on underground.

By definition, forest is a large area covered chiefly with trees and undergrowth, but the very essence of the forest lies in the soil on which it stands. In the soil lies a network of life, linking trees with their roots. But trees need a bit of help to communicate with each other, a translator to say.

Everything starts with hub trees – the tallest and oldest trees in the forest. Their size gives them wider access to sunlight, and thus they get more food than they need through the process of photosynthesis. Around the roots live the fellow citizens of the soil – fungi. Fungi make root-like formations in the soil, called mycelium. They grow within the root system of trees to absorb the excess sugar, and in return they give nutrients and water to the roots. This symbiotic fungal network connects the roots from different trees and makes a communication system, a translator for the trees beneath the ground. This communication network is used for sending the water and nutrients to the trees in need. Seedlings rely on this network for their growth, because they are not tall and developed enough to reach the sunlight and get the food themselves. Sick or dying trees may release their nutrients in the network, for them to be used by their healthier neighbors. Trees can even send each other warning signals through this communication system – releasing chemical signals of an attack, fungi carry these signals to neighboring plants, for them to know when to raise their defenses.

photo by Jesse Gardner

But it’s not altruistic and lovely all the time. Some plants evolved to “hack” this system. For example, black walnut spreads toxic compounds through the network to poison their rivals, seeing them as competitors for food; some species of orchids just plug in and steal resources from neighboring trees and plants.

Discovery of communicating trees was brought to light in an experiment in British Columbia, Canada. Scientists used DNA analysis to map the fungal network in a forest. They found that the hub trees are connected to almost all younger trees in the forest, taking care of them and sending needed nutrients. Removing these hub trees would cause a more significant loss in communication and nutrient traffic than just randomly removing trees. This knowledge is really important for conservation and planting new forests, as it allows us to make them stronger and more resilient.

Forest seems to be a peaceful and quiet place, but actually there is a lot of chatter going on beneath. Next time you walk in the shade of the treetops, you might like to think of the forest as a big unity, a superorganism with multiple individual manifestations, silent but constantly talking. That’s what woodlands are – a big unified society, making a single body underneath your feet.