Forests share sugar and warnings through a fungal network underground

Fungal threads called mycorrhizae link the roots of different trees into a shared network. Ecologist Suzanne Simard showed older 'mother trees' can send carbon and nutrients through these threads to shaded seedlings, including ones of other species, and that stressed trees release chemical signals other trees respond to.

— Suzanne Simard, Finding the Mother Tree — Knopf, 2021; building on her 1997 Nature paper on interplant carbon transfer