Litterfall and leaf litter decomposition in a central African tropical mountain forest and Eucalyptus plantation

In the pristine forest, the initial decay rate was highest for Cleistanthus polystachyus (CP) leaf litter (0.0330 day−1), followed by the forest litter mixture (PE + CP + CG) (0.016 day−1), and was lowest for Parinari excelsa (PE) (0.0094 day−1). The final decay rate of CP, Carapa grandiflora (CG) and Eucalyptus litter mixture were similar (0.0014, 0.0013 and 0.0017 day−1) and lower than the final decay rate of forest litter mixture (PE + CP + CG) (0.0021 day−1). Decay rates could be related to litter properties such as nitrogen, lignin, Ca and polyphenol content. Mixing litter species caused a negative additive effect on the initial, while a positive additive effect was observed on the final decay rate in the pristine forest stand. Taken together, mixed-species litter showed increased mass loss compared to the expected weighed-based mass loss from the individual litter types in the mixture. Finally, stand type only affected the final decay rate of forest litter mixture (PE + CP + CG) that was lower in Eucalyptus than in pristine forest and is suggested to be caused by reduced forest floor humidity.