00 · IN THREE MINUTES

The answer in three steps

  1. 1Plant roots trade carbon for nutrients and water with mycorrhizal fungi.
  2. 2A fungal individual or network can contact multiple plants, creating a .
  3. 3Transfer in experiments is real, but its quantity, ecological benefit and prevalence in intact forests are often uncertain.

01 · THE PARTNERSHIP BEGINS AT ROOTS

The partnership begins at roots

Fungal hyphae extend the soil volume explored around a root. Plants supply photosynthetic carbon, while fungi can improve access to phosphorus, nitrogen and water.

02 · CONNECTIONS ARE PHYSICALLY POSSIBLE

Connections are physically possible

Genetic and tracing methods show that the same fungal genet or interconnected hyphae can associate with several plants. That architecture creates a route for molecules to move.

03 · MOVEMENT IS NOT THE SAME AS HELP

Movement is not the same as help

Carbon, nutrients and signalling compounds have moved between plants in experiments. A detected transfer may be tiny, driven by source-sink physics or consumed by the fungus rather than donated by one tree.

FIG. 03The answer in three steps
A conceptual model: the geometry shows relationships, not measured scale.

04 · FIELD EVIDENCE IS DIFFICULT

Field evidence is difficult

Roots, fungi and soil overlap in complex ways, and excluding fungal pathways can alter many other conditions. Results from pots or seedlings do not automatically scale to mature forests.

05 · THE NETWORK METAPHOR CAN MISLEAD

The network metaphor can mislead

Terms such as “wood wide web” are memorable but can imply intention, central control or universal cooperation. Fungi and plants have partly aligned and partly competing interests.

06 · SOURCES AND EVIDENCE

Sources and evidence

The explanation follows the evidence chain below. Links open the original source.

  1. 01
    Positive citation bias and overinterpreted results on common mycorrhizal networks

    Supports a specific claim or evidence boundary used in this article.

    PEER-REVIEWED REVIEW ↗
  2. 02
    Mycorrhizae

    Supports a specific claim or evidence boundary used in this article.

    INSTITUTIONAL EXPLAINER ↗
  3. 03
    Common mycorrhizal networks: an overview

    Supports a specific claim or evidence boundary used in this article.

    PEER-REVIEWED REVIEW ↗
CHANGE LOG28 Aug 2026 · First five-language edition; claims, evidence boundaries and visual model checked.