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Can Trees Communicate?

The idea that trees talk to each other has become one of those science-adjacent stories that travels fast and gets simplified faster. Popular accounts tend toward the lyrical: forests as communities, trees as mothers feeding their children, a “wood wide web” humming with intention underground. The reality, as research published in 2025 has made increasingly clear, is stranger and more interesting than either the romantic version or the skeptical pushback against it.

What the fungal network actually does

In February 2025, a team led by Toby Kiers at Vrije Universiteit Amsterdam, working with researchers from six countries, published a study in Nature that gave the clearest picture yet of how mycorrhizal fungal networks operate underground. The team built a custom imaging robot capable of tracking over 500,000 individual network nodes and more than 100,000 internal flow paths in a living fungal mat in real time, far more detail than any previous method could capture.

What they found was not a passive pipeline. The fungal networks build and maintain themselves as self-regulating systems, sending exploratory filaments ahead like advance scouts while sustaining two-way traffic of carbon, phosphorus, and water along established routes back to plant roots. The flow was organized as “travelling waves,” rhythmic pulses that helped the network distribute resources across long distances, responding to local conditions as they changed.

“The network is not just a pipe. It is actively making decisions about where to send resources and when,” said Kiers. “That is a form of distributed problem-solving.” 

Roughly 80% of plant species on Earth maintain these fungal partnerships, including most trees in temperate and boreal forests. The fungi receive sugars from plant roots in exchange for minerals the plant cannot extract from soil on its own. It is a trade relationship that has been running for approximately 450 million years, and the 2025 Nature study is the first to watch it function in something approaching real time.

Signals, warnings, or eavesdropping?

A separate question is whether trees send deliberate warning signals to neighbors when attacked by pests or disease. This is the claim that generated the most popular enthusiasm, and it remains the most contested. The evidence for chemical signaling through the air, via volatile organic compounds, is solid. A damaged or infected tree does release compounds that neighboring trees and fungi demonstrably pick up and respond to, often by increasing their own chemical defenses.

But a 2025 analysis connected to researchers at Oxford raised a pointed question: does it matter whether the signaling is intentional? The researchers argued that framing tree chemical releases as “warnings” imports a concept of intention that the evidence does not support. A tree releasing compounds when damaged is doing something more like bleeding than speaking. Neighboring trees that respond are doing something more like detecting and reacting than listening and understanding. The word “communication” is being asked to carry more weight than the biology justifies.

The debate over the wood wide web

The “wood wide web” framing has attracted significant scientific criticism over the past three years. A 2023 meta-analysis in Nature Ecology & Evolution reviewed the experimental evidence for carbon transfer between trees via fungal networks and found that most studies were conducted under laboratory conditions or with seedlings, not mature forest trees. Under natural conditions, it remains genuinely unclear whether older trees routinely feed younger ones through the network, or whether the carbon that moves through the fungi primarily feeds the fungi themselves.

What is not in dispute is that the networks exist, that they influence which trees survive and which don’t, and that disrupting them through clear-cutting or soil compaction has measurable effects on forest recovery. The debate is about interpretation, not existence.

What the science actually supports

Strip away the overclaims and what remains is still remarkable. Forests are metabolically interconnected in ways that were entirely unknown 30 years ago. Individual trees are not isolated organisms competing for light and water. They exist inside a dense network of chemical and fungal relationships that shapes their growth, their immune responses, and their survival. The 2025 Nature imaging study shows that network operating as a dynamic, self-organizing system, routing resources where they are needed, withdrawing from failing branches, exploring new territory.

Whether that constitutes communication depends on where you draw the line between a signal and a word. But even on the conservative reading, the underground life of a forest is nothing like what biology textbooks described a generation ago.

Sources

·         Oyarte Gálvez, L., Kiers, E.T., et al. (2025). Real-time imaging of mycorrhizal network dynamics. Nature.

·         Flör, V., et al. (2023). Reappraisal of the evidence for the wood wide web. Nature Ecology & Evolution.

·         Oxford analysis (2025). Intentionality and chemical signaling in forest ecosystems.

Source: Can Trees Communicate? – Scents of Science