Effect of litter quality and Home-Field advantage on leaf-litter decomposition of Tree of heaven and European black pine leaf-litters

Litter quality plays a key role in the decomposition process and nutrients dynamics. In most studies, it is assumed that litter has a higher rate of decomposition in its ecological site. Evidence for this theory has not yet been fully confirmed. Therefore, in order to test this theory and also to investigate the effect of litter quality on its decomposition rate in two stands of european black pine (Pinus nigra Arnold) and tree of heaven (Ailanthus altissima Mill.) leaf-litters of P. nigra Arnold and A. altissima Mill were incubated for 180 days using the litterbag method in Shahed's forest park of Malayer. The chemical quality of litter, the rate constant for decomposition, the main ecological site advantage and the effects of mixtures litter were investigated through the relevant relations. Results showed that the rate constant for decomposition of A. altissima litter (with high levels of nitrogen and calcium and low C/N ratio) was higher than P. nigra (0.09 and 0.05, respectively). Competitive status was observed in all compounds except P. nigra samples in their sites. Also, the decomposition rates of the litters had a significant positive relationship with the concentrations of nitrogen (r = 0.76, p <0.05) and phosphorus (r = 0.62, p <0.05) and had a significant negative relationship with the concentration of potassium (r = -0.74, p <0.05) and C/N ratio (r = -0.76, p <0.05). The theory of home-field advantage was confirmed about european black pine and tree of heaven in their own ecological sites. In general, the results showed that the decomposition process is affected by both litter quality and home-field advantage of leaf-litter decomposition. According to the research results, mixed afforestation of these two species was suggested in the temperate cold climates of the west of the country.