Decomposition of black locust and black pine leaf litter in two coeval forest stands on Mount Vesuvius and dynamics of organic components assessed through proximate analysis and NMR spectroscopy

► Black locust and black pine litters undergo distinct early humification processes. ► Litter decay rate was negatively correlated to AUR concentration in both litters. ► MC-to-PC (an index of lignin content) regulated litter decay rate of black locust. ► O-Alkyl-C and Alkyl-C regulated litter decay rate of black pine. ► Most decomposable fractions were Phenol-C in black locust and O-Alkyl-C in black pine.