When Suzanne Simard began working in forestry after college, conventional theory held that trees were isolated loners engaged in a cutthroat Darwinian competition for water, sunlight, and food. Timber companies planted rows of the most lucrative species and eradicated most of the competition—a “plantation” approach that Simard felt ignored the messy genius of nature, with its many interwoven species.
In a series of breakthrough experiments conducted while dodging grizzly bears in western Canada’s rainforests, Simard discovered that trees are connected through vast fungal root systems known as mycorrhizal networks. Via this subterranean pipeline, they share carbon, water, and nutrients. The fungi extract sugars from the tree roots that they can’t produce on their own, and in return the fungi ferry water and nutrients to the tree roots and even farther,…