Tree diversity increases productivity through enhancing structural complexity across mycorrhizal types

Abstract

Tree species diversity and mycorrhizal associations play a central role for forest productivity, but factors driving positive biodiversity-productivity relationships remain poorly understood. In a biodiversity experiment manipulating tree diversity and mycorrhizal associations, we examined the roles of above- and below-ground processes in modulating wood productivity in young temperate tree communities and potential underlying mechanisms. We found that tree species richness,but not mycorrhizal associations, increased forest productivity by enhancing aboveground structural complexity within communities.Structurally complex communities were almost twiceas productive as structurally simple stands, particularly when light interception was high. We further demonstrate that overyielding was largely explained by positive net biodiversity effects on structural complexity with functional variation in shade tolerance and taxonomic diversity being key drivers of structural complexity in mixtures. Consideration of stand structural complexity appears to be a crucial element in predicting carbon sequestration in the early successional stages of mixed-species forests.

Rémy Beugnon

I am a PosDoc between iDiv, the CEFE and LIM working biodiversity-microclimate-ecosystem functioning nexus.