Conscious: A Brief Guide to the Fundamental Mystery of the Mind

by Annaka Harris

In a 2016 TED talk, she described the thrill of uncovering the interdependence of two tree species in her research on mycorrhizal networks—elaborate underground networks of fungi that connect individual plants and transfer water, carbon, nitrogen, and other nutrients and minerals. Simard was studying the levels of carbon in two species of tree, the Douglas fir and the paper birch, when she discovered that the two species were engaged “in a lively two-way conversation.” In the summer months, when the fir needed more carbon, the birch sent more carbon to the fir; at other times when the fir was still growing but the birch needed more carbon because it was leafless, the fir sent more carbon to the birch—revealing that the two species were in fact interdependent. Equally surprising were the results of further research led by Simard, showing that Douglas fir “mother trees” were able to distinguish between their own kin and a neighboring stranger’s seedlings. Simard found that the mother trees colonized their kin with bigger mycorrhizal networks, sending them more carbon belowground. The mother trees also “reduced their own root competition to make room for their kids,” and, when injured or dying, sent messages through carbon and communicated other defense signals to their kin seedlings, increasing the seedlings’ resistance to local environmental stresses.5