How Trees Talk Through Root Networks

By Nina Walsh · September 29, 2026

The Wood Wide Web

Trees are not solitary organisms competing in isolation. Underground networks of mycorrhizal fungi connect tree roots, forming what ecologist Suzanne Simard called the Wood Wide Web. Trees exchange nutrients, send warning signals, and recognize their own offspring.

Mycorrhizal Networks

Fungi form sheaths around roots and extend thread-like hyphae to neighboring trees. A single tree connects to hundreds of neighbors. Fungi receive sugars and deliver water and minerals in return.

Nutrient Sharing

Mother trees channel carbon and nutrients to younger seedlings, especially their own offspring. Birch shares carbon with fir in summer; fir reciprocates in spring and fall.

Warning Signals

When attacked by insects, trees release chemical signals through the network. Neighbors begin producing defensive compounds before insects reach them.

Kin Recognition

Trees distinguish their seedlings from unrelated plants. Mother trees send more carbon to offspring and reduce root competition to give seedlings space. When dying, they accelerate nutrient transfer to the next generation.

Implications for Gardeners

Avoid disturbing soil around established trees — tilling destroys fungal networks. New plantings near established trees benefit from existing mycorrhizal connections. Inoculating with mycorrhizal fungi helps new plants connect faster.

The Dark Side

Some plants use fungal connections to spread allelopathic chemicals that inhibit competitors. Parasitic plants tap into networks to steal nutrients. The Wood Wide Web is a marketplace, not always a charity.