How Much Room Does a Mushroom Need? - About 110 Quadrillion Kilometres

Beneath your feet is a vast network of fungi. Not merely "quite large" vast, but vastly, hugely, mind-bogglingly vast. If every strand of these underground fungal networks were laid end-to-end, they would stretch from Earth to the Sun about a billion times.

To put that into perspective, if you could travel at the speed of light, it would take you nearly 12 years to cover that distance. Yet almost all of this immense biological infrastructure remains hidden beneath our feet.

Arbuscular mycorrhizal fungi are microscopic soil fungi that form partnerships with the roots of most land plants. Their thread-like filaments create vast underground networks that transport water and nutrients between plants and soils while helping to move and store enormous amounts of carbon.

The new Mycorrhizal Infrastructure Map reveals where these underground fungal networks are most densely concentrated. Created by the Society for the Protection of Underground Networks (SPUN) and based on research published this month in Science, the map provides the first global estimate of the distribution and scale of these fungal networks.

To create the map, researchers combined data from 16,000 soil samples collected at more than 4,000 locations worldwide with climate, vegetation and soil chemistry data. Machine-learning models were then used to predict fungal network densities for every square kilometre of vegetated land on Earth, including regions that have never been sampled.