Dioecy may subject females and males to contrasting selective pressures, leading to differences in adaptive traits associated with resource allocation and ecophysiology across sex. Such differences may then exert carry-over effects on the surrounding ecosystem. However, effect of different sex combinations over ecosystem biogeochemical cycles, via organic matter decomposition, has not yet been addressed. Here, we used different combinations of female and male Populus cathayana to elucidate the carry-over effects of dioecy on organic matter decomposition.