Soil microbial community structure of monoculture and mixed plantation stands of native tree species in south subtropical China. Effects of N-fixing Tree Species on Soil Microbial Biomass and Community Structure of the Second Rotation Eucalyptus Plantations Characteristics of soil microbial community structure in two young plantations of Castanopsis hystrix and Erythrophleum fordii in subtropical China Role of nitrogen fixing trees in mixed forest Ⅲ Leaf litter decomposition and its N release of nitrogen fixing tree species Variations of nutrient contents and its numerical classification among nitrogen-fixing and non-nitrogen-fixing tree species of north deciduous trees Carbon and nitrogen storage in monoculture and mixed young plantation stands of Erythrophleum fordii and Pinus massoniana in subtropical China Effects of Chinese-fir mixing with N-fixing and non-N fixing tree species on forestland quality and forest-floor solution chemistry