EFFECTS OF ABOVEGROUND LITTER EXCLUSION AND ADDITION ON SOIL RESPIRATION IN A CUNNINGHAMIA LANCEOLATA PLANTATION IN CHINA Impact of litterfall addition and exclusion on soil respiration in Cunninghamia lanceolata plantation and secondary Castanopsis carlesii forest in mid-subtropical China Impacts of Biochar Input on Soil Carbon Emission and Microbial Community Composition in Cunninghamia lanceolata Plantation Effects of understory removal on soil respiration and microbial community composition structure in a Chinese fir plantation