Forest Trees May Communicate Through Hidden Underground Fungal Networks

Field report

Changing patterns of nutrient exchange seem to indicate underground communication

Katherine Martinko is an expert in sustainable living. She holds a degree in English Literature and History from the University of Toronto.

You may not think mushrooms can talk but one scientist claims they communicate with each other, using up to 50 words. The study, titled "Language of fungi derived from their electrical spiking activity," by Andrew Adamatzky, who runs the appropriately named Unconventional Computing Laboratory of the University of the West of England, has everybody talking.

Some are not taking his research seriously—comedian Jimmy Fallon accused him of "talking shiitake"1—but here at Treehugger, we have always been open to conversations withslime moldandtreesvia theWood Wide Web.

Adamatzky, who previously published research aboutbuilding a fungal computerand dressing up inliving wearables made from slime mold and fungi, inserted electrodes into four different kinds of fungi: ghost fungi (Omphalotus nidiformis), Enoki fungi (Flammulina velutipes), split gill fungi (Schizophyllum commune), and caterpillar fungi (Cordyceps militaris).

He observed spikes of electrical activity, which is common in all creatures. However, the fungi displayed changing patterns of activity that could be interpreted as communication:

In other words, they appear to be responding to what is happening to them and then talking about it.

Forest ecologist / Getty Images

You may not think trees can talk but one scientist claims they share nutrients and warning signals with each other through underground fungal highways. The research, titled "Mycorrhizal networks and forest communication," by Suzanne Simard, who runs the renowned forest ecology program at the University of British Columbia, has everybody talking.

Some are not taking her research seriously — skeptics accused her of "seeing sentience in saplings"1—but here at Treehugger, we have always been open to conversations withslime moldandtreesvia theWood Wide Web.

Simard, who previously published groundbreaking research aboutmother trees nurturing seedlings through fungal linksand documenting how carbon flows from older trees to younger ones through mycorrhizal networks, studied forests of Douglas fir, paper birch, and western red cedar — the towering conifers that dominate the Pacific Northwest.

She observed pulses of carbon and nutrients flowing through the fungal network, which is common in all forest ecosystems. However, the trees displayed changing patterns of nutrient transfer that could be interpreted as communication:

In other words, they appear to be responding to what is happening to them and then signaling about it.

Much depends on one's definition of "communication." Simard discusses chemical signaling among trees through mycorrhizal fungi, root exudates, and airborne compounds. This is not communication as humans think of it, but the Wood Wide Web is active and we should take what the trees are signaling seriously.

Simard notes, "A modified conception of communication in forests is considered to be a pathway towards 'the de-objectification of trees and the recognition of their subjectivity and inherent worth and dignity.'"2

So, the question is: Are the patterns of carbon and nutrient flow actually communication? Listening to forests takes patience. A single nutrient transfer can take hours to traverse from one tree to another through the fungal highway underground.

The ancient forests of the Pacific Northwest are chatterboxes by comparison to lonely street trees. When all the carbon flows were plotted out, Simard compared the patterns of exchange to those of a social network. She studied the patterns in the nutrient flows and concluded they are definitely sharing resources among themselves.

The research states, "We recorded carbon transfer between Douglas fir and paper birch through ectomycorrhizal networks. We found evidence of bidirectional nutrient exchange propagating along the mycelial links. We speculated that carbon transfer through mycorrhizal networks is a manifestation of the resources communicated between connected trees in a forest."2

Looking at the repeating patterns, she found that "the size of the fungal network can link hundreds of trees; however, the core hub of most frequently connected trees does not exceed 15–20 individuals."2

The different species of trees shared resources through fungal networks with varying degrees of generosity, and Simard admits she doesn't understand everything they are signaling. "That said, we should not expect quick results: we are yet to fully decipher how trees communicate despite studying forests for centuries, and research into mycorrhizal communication is in its pure infant stage," writes Simard in the study.2

Indeed. In another paper, "Mother Trees and the Wood Wide Web," released at the same time but building on decades of work, Simard and her team of researchers use the same data and go further than asking whether trees communicate, but whether older trees actively nurture their offspring through fungal networks.