Effects of Thinning Intensity on Soil Organic Carbon and Labile Components in Sprout Cunninghamia lanceolata Plantation

In December 2017, experiment of thinning intensity of 50% and 70% was implemented on sprout 12-year Cunninghamia lanceolata plantation in Lin’an, Zhejiang province. Continuous observation was carried out on soil organic carbon and labile components of the experimented stand in 2018 and 2019. The result shows high-intensity thinning increased soil organic carbon and its active components (soil microbial biomass carbon, water-soluble organic carbon and readily oxidizable organic carbon) by increasing soil carbon sources and changing the soil microenvironment. The seasonal changes of soil organic carbon were not obvious, but the three labile soil organic carbon components obvious, which were not affected by thinning.