The secret language of trees

Camille Defrenne and Suzanne Simard

Most of the forest lives in the shadow of the giants that make up the highest canopy. These are the oldest trees, with hundreds of children and thousands of grandchildren. They check in with their neighbors, sharing food, supplies, and wisdom gained over their long lives.

The secret to their success lies under the forest floor, where vast root systems support the towering trunks above. Partnering with these roots are symbiotic fungi called mycorrhizae.

These fungi have countless branching, thread-like hyphae that together make up the mycelium. The mycelium spreads across a much larger area than the tree root system and connects the roots of different trees together. These connections form mycorrhizal networks. Through mycorrhizal networks, fungi can pass resources and signaling molecules between trees.

These fungi make sure that the forest as an ecosystem, and trees and plants as components of it, look out for one another. They supply a deficient resource to the organisms that need it, transporting it from the organisms that have an excess of it.

These fungi pass an incredible amount of information between trees. Through the mycorrhizae, trees can tell when nutrients or signaling molecules are coming from a member of their own species or not. They can even tell when information is coming from a close relative like a sibling or parent. Trees can also share information about events like drought or insect attacks through their fungal networks, causing their neighbors to increase the production of protective enzymes in anticipation of threats.