The Wood Wide Web

Beneath every forest floor lies a vast network of mycorrhizal fungi connecting tree roots. Through this fungal internet, trees share nutrients, send chemical warnings about insect attacks, and even transfer resources from healthy trees to sick neighbors.

Ecologist Suzanne Simard proposed that mature mother trees can recognize their own seedlings through the fungal network and channel extra carbon and nutrients to them. It is an influential idea, but a contested one — recent reviews argue the field evidence for such kin-preferential transfer is still too weak to confirm. What is clearer is that the fungal network links many trees at once, which complicated the older picture of a forest as nothing but individuals competing for light and soil. Whether "cooperation" is the right word for what happens belowground remains actively debated among ecologists.