Results
Across six temperate forests, we quantified total root-derived C accumulation and root production in 54 plots spanning a gradient of AM-associated vs. ECM-associated tree dominance. Overall, we found that both total root-derived soil C and root-derived MAOM-C were greater in AM-dominated plots while root production was greatest in ECM-dominated plots. Importantly, annual root-derived soil C accumulation was greater than aboveground litter mass C inputs and rivaled ANPP in magnitude, highlighting the importance of this often poorly quantified component of ecosystem C budgets.