Predicted richness of ectomycorrhizal fungal OTUs, symbionts of tree roots (OTUs per 100 m²).
Predicted ectomycorrhizal fungal richness in OTUs per 100 m² of soil, at about 1 km, worldwide. 3Bee reproduction of the published SPUN model (Van Nuland et al. 2025, Nature, CC-BY 4.0) — NOT the official SPUN product. Against the published Figure 2: r 0.965, median bias -0.33. It under-calls the boreal maximum above 60 degrees north by 3 to 5 OTUs and over-calls mid-latitudes by 2 to 4. On a small site the value describes the surrounding landscape, not a field measurement.