Science shows trees communicate with each other
YouTube video Esoteric Detective
They might seem like the strong, tall and silent type, but trees actually communicate with each other.
Forest ecologist Dr Suzanne Simard, from the University of British Colombia, studies a type of fungi that forms underground communication networks between trees in North American forests.
“We found that the biggest oldest trees had more connections to other trees than smaller trees. It stands to reason because they have more root systems,” she says.
Fungal networks don’t just operate between related trees, but also between trees of different species in the same native community.
When she shaded one tree, carbon-based sugars would flow into it from the other tree.
So rather than competing for resources, these two trees were using fungal networks to share them.
Other evidence shows trees use fungal networks to warn their neighbours about impending attacks from pests.
“When trees are attacked, they increase their defence against the invaders by regulating their defence genes to make defence enzymes,” says Dr Suzanne Simard.
“Research suggests they also send chemical signals down into their roots through their fungus networks to their neighbours, which then detect these signals and regulates their own defence genes.”
Lab studies have recorded defence signals travelling between trees in as little as six hours.
When fungal networks are intact they allow a greater diversity of trees, each with their own strengths and weaknesses, to survive in the forest.
Dr Suzanne Simard says her findings have implications for forestry practices that target old-growth trees.
“We need to leave these legacy trees and let them send their messages into the soil to surrounding plants,” she says.
“This will help the recovery of forests following disturbance such as logging or fire.”
Conserving fungal networks that help forests recover from disturbance could also prevent invasions by exotic species, which often compete with the endemic networks, she believes.