Microenvironment has little effect on the litter decomposition rate of temperate trees

Individual tree species might affect underground soil properties to favor the decomposition of their own litter. However, in some studies, monospecific litter decomposed faster underneath multispecific canopies than under canopies of the same species as the litter, suggesting that plant diversity in the overstorey creates a more favorable decomposition microenvironment. We compared the decomposition rate of monospecific litter from eight temperate tree species under the crown of the same species as the litter (conspecific canopy), and a multispecific canopy formed by eight species. Using model selection, we determined the influence of the microenvironments, species, and litter chemistry on decomposition rates. The most robust model included the species and canopy type, but it differed only slightly from the model including only the species. Decomposition rates were significantly different among species and higher in conspecific canopy than multispecific canopy in all species. Models including specific leaf area and different combinations of chemical traits of the litter were less robust than the null model. These results show that the species origin of the litter was significantly more important than the microenvironment to explain litter decomposition rates.