Suzanne Simard: How Do Trees Collaborate?

Trees are “social creatures” that communicate with each other in cooperative ways that hold lessons for humans, too, ecologist Suzanne Simard says.

Simard grew up in Canadian forests as a descendant of loggers before becoming a forestry ecologist. She’s now a professor of forest ecology at the University of British Columbia.

Trees are linked to neighboring trees by an underground network of fungi that resembles the neural networks in the brain, she explains. In one study, Simard watched as a Douglas fir that had been injured by insects appeared to send chemical warning signals to a ponderosa pine growing nearby. The pine tree then produced defense enzymes to protect against the insect.

“This was a breakthrough,” Simard says. The trees were sharing “information that actually is important to the health of the whole forest.”

In addition to warning each other of danger, Simard says that trees have been known to share nutrients at critical times to keep each other healthy. She says the trees in a forest are often linked to each other via an older tree she calls a “mother” or “hub” tree.

In connecting with all the trees of different ages, [the mother trees] can actually facilitate the growth of these understory seedlings,” she says. “The seedlings will link into the network of the old trees and benefit from that huge uptake resource capacity. And the old trees would also pass a little bit of carbon and nutrients and water to the little seedlings, at crucial times in their lives, that actually help them survive.”

The study of trees took on a new resonance for Simard when she was diagnosed with breast cancer. During the course of her treatment, she learned that one of the chemotherapy medicines she relied on was actually derived from a substance some trees make for their own mutual defense. She explains her research on cooperation and symbiosis in the forest, and shares her personal story in the new memoir Finding the Mother Tree: Discovering the Wisdom of the Forest.