Mycorrhizal fungi are critical members of the forest microbiome, and are central to how trees interact with their soil environment. There is increasing interest in how the composition of soil microbiome, and particularly tree mycorrhizas, may affect forest function, yet to date, direct evidence is scarce. Here, we collected forest mycorrhizal composition data from root tip sequencing surveys across >100 European forest monitoring sites. Using this dataset, we asked if features of the forest mycobiome could explain variation in tree growth, and the response of tree growth to environmental drivers of temperature and nitrogen deposition.
Results/Conclusions
Here we show that variation in soil microbiome features is linked to tree growth and forest carbon sequestration rates. Variation across soil fungal communities was linked to a ~40% increase in forest growth and carbon sequestration rates, and this effect was independent of tree species identity, tree size and stand structure, climate, and soil properties. Decomposition of fungal trait space using available genomes suggests these contrasting fungal communities are linked to relative investment in inorganic vs. organic soil nitrogen acquisition strategies. While causal inference is certainly limited in any observational analysis, these findings are consistent with the idea that different fungal communities can cause forests to grow at different rates, and provide a critical starting point for manipulative experiments that seek to engineer the forest microbiome.