Trees Communicate Via a Vast Underground Network of Fungi

Suzanne Simard wants you to think about trees differently, not as rugged individualists bravely facing the world alone, but as part of a vast social world connected by an invisible underground network.

Her views are firmly rooted in scientific research and her ideas represent nothing less that a paradigm shift in ecological thought.

For over 30 years, Simard has been watching and listening to trees. She is a forest ecology professor at the University of British Columbia's Department of Forest and Conservation Sciences in Vancouver.

Recently in TED talk, Simard discussed a new way of thinking about plant communities, a new vision of the forest.

Simard's views are hard-won, and she came upon them not by looking above ground in the forest but below. She concentrated on a little-understood aspect of forest biology: the extensive fungal networks that form enormous underground connections unseen to the casual observer.

When most of us think of a fungus in the forest, we think of mushrooms or morels. Those are the reproductive organs of fungi, growing upward out of the soil to hold the spores aloft so they can be blown by the wind and dispersed.

But the vegetative body of a typical forest fungus is quite different. It is a hypha, a branching strand of nucleated cells, largely invisible to the unaided eye.  

Thousands or millions of these hyphae exist under a forest floor, forming a mycelium, a dense often white mass that feeds off dead and decaying organic matter in the soil. These mycelia form undergrown networks of vast complexity -- networks that can link on tree to another.

When fungal mycelia connect with tree roots, they often a form a mutually beneficial structure called a mycorrhizum, root plus fungus. This is a place where chemical exchanges can take place.

When two trees are connected by a mycelial network and mycorrhiza, neither is harmed. In fact, the fungus allows for chemical communication between the trees. Carbon, nitrogen, phosphorus, water and other chemicals will pass from one tree to another. Simard tracked these chemicals using ingenious radioactive tracers to follow the movement from one plant to another.

What Simard and her colleagues have found out is that trees in a forest are not isolated individuals, standing alone in the ecosystem to live or die. They are part of a complex, interconnected communication network, passing chemicals from one to another, communicating and even helping. Certain trees, called hub trees or mother trees, are particularly powerful communicators. They can even sense their own offspring and send greater nutrients to them.

This makes for a completely new vision of a forest. How do we change our logging and forestry practices now that we know that each individual tree communicates with its neighbors? How does this fact change the way we interact with forests around us?