When scientists first studied the structure of nerve cells that form the human brain, they noted their strong resemblance to trees. In fact, dendrites, which are projections from a nerve cell, comes from the Greek word Dendron, for “tree.” But not until recently did scientists realize that trees and nerve cells share more than passing resemblance. We now know that trees have their own sort of nervous system, one that is capable of facilitating tree communication, memory, and learning.

At the heart of tree communication are roots that reach deep into the earth, and often, far and wide. Down there, hidden under the surface, lies a vast network of tree roots that “talk” to one another as if they are friendly neighbors.

“They really are sort of like neighborhoods,” says tree scientist Dr. Nalini Nadkarni. “I have neighbors, and I communicate with them. I borrow sugar from them. Well, trees are really the same way. Tree roots can leak out sugars and other compounds into the soil. Those sugars are then sucked up by neighboring roots.”

Indeed, tree can share nutrients with far-away neighbors by enlisting the help of underground fungi, forming a symbiotic network of roots and fungi called mycorrhizal networks. Trees use these networks to ferry water and nutrients as well as to communicate with each other, for example, by sending distress signals about drought and disease or insect attacks. Other trees then alter their behavior upon receiving these messages, thus averting potential damage to their health and survival. More remarkably, even trees that live in deserts display the same “neighbourliness” with other trees despite the scarcity of water and minerals (see video). Without this amazing mycorrhizal network, forests would not survive, let alone thrive, and the consequences this has for our planet’s survival is unthinkable.

The Mycorrhizal Network in Two Pictures

Watch: Trees in the Taklamakan Desert

Further reading