Variable Description Data type Min, mean, max
Substrate White- and brown-rot logs and soil Category
Openness Canopy openness above the substrate, % Continuous 0.9, 13.1, 29.6
Diameter Diameter of the logs, cm Continuous 18.8, 31.2, 62
Length Length of the logs, cm Continuous 62.0, 92.7, 200
pH Substrate pH Continuous 3.8, 4.5, 5.4
Water Substrate water content, % Continuous 7.0, 22.9, 41.8
Nutrient_PC1 Principal component 1 in PCA of substrate nutrient ions Continuous –243.8, 0.0, 25.8
ECMF richness OTU richness of ectomycorrhizal fungi in the substrate Continuous 0, 0.8, 5
AMF richness OTU richness of arbuscular mycorrhizal fungi in the substrate Continuous 0, 1.1, 10
ECMF infection Infection ratio of ectomycorrhizal fungi in seedling root, % Continuous 0, 18.4, 89.0
AMF infection Infection ratio of arbuscular mycorrhizal fungi in seedling root, % Continuous 0, 54.2, 100