How do trees communicate through underground fungal networks?

The answer

Mycorrhizal fungi form vast underground networks, sometimes called the 'Wood Wide Web,' that connect the root systems of trees and other plants. Through these networks, trees can share nutrients like carbon, nitrogen, and phosphorus, and even send chemical warning signals about insect attacks to neighboring trees. About 90% of land plants form mycorrhizal partnerships, and a single fungal network can connect dozens of trees across a forest. Mother trees have been shown to preferentially send resources to their own seedlings through these connections.