The chitter-chatter of forest fungi

The mythologies of virtually every ancient civilisation have recorded instances of trees that speak. In some cases, they delivered prophecies; in others, they engaged in lofty philosophical debates. In more contemporary times, a group of Japanese scientists has established that a network of fungi in the hilly Tohoku region in Japan effectively communicate using an underground 'internet' of sorts.

More precisely, the researchers recorded electrical signals in mushrooms connected to the roots of trees in Tohoku; their findings were published in the journal Fungal Ecology (bit.ly/speaking-trees).

"Fungi have a massive underground network," says Yu Fukasawa, an ecologist at Tohoku University. He and his team set out to explore the Tohoku forests in the belief that an understanding of fungal ecology would help them understand the ecology of the whole forest.

Tohoku has pine, fir and birch trees – and various types of fungi connected to the roots of the trees. The two are mutually dependent; the underground mushroom network absorbs nutrients from the soil and transfers them to the tree roots in exchange for other nutrients.

"We were looking for signal transfer in the underground fungi network because they could be the possible messenger of the forest," says Fukasawa. The researchers fixed electrodes on mushrooms in various parts of the jungle and recorded electrical pulses produced by them. They recorded over 100 millivolts of electric potential in the mushrooms, and found a spike in signal generation in the mushrooms after rains.

Strikingly, they found that the mushrooms were 'talking' continuously during downpours. "Perhaps rain energised them," quips Fukasawa. The study, which lends credence to speculation about fungal communication, also establishes that news of an incident or an impact can likely travel from one part of the forest to another. Based on the finding, ecologists may be able to predict a forest's response to environmental changes in the future.

The researchers largely used the fungus Laccaria bicolor for their experiments, but they also tested other types of fungi. "Mushrooms can transfer negative and positive information," says Fukasawa. Through this network, they can, for instance, communicate a predator attack to neighbouring mushrooms in order to protect them, he adds.

Fukasawa's goal is to listen to the forest's response to climate change in its language. Forests probably have some kind of computing ability, he reckons. "Detecting (this) is our long-time goal."

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There's magic in these mushrooms