Responses of the respiration and carbon sequestration of soil to different mixed forest types are mediated by stand structure

Our research hypothesis is that the effects of different mixed forest planting types on soil carbon stocks are different. These differences come from the different soil carbon input sources of understory plants on the one hand, and the differences in soil respiration caused by the water and heat environment of the forest and soil properties on the other. Forest structure mediates the whole process of the input of forest understory environment and soil carbon, as well as respiratory loss for different planting types. Our data include three treatment planting types: MPF, MCLMF, and MLMF. Soil respiration values, SR soil temperature ST, soil moisture SW, and soil bulk density SBD were measured from January to December 2024. Forest spatial structure indices (M, CI, W, O) and forest non-spatial structure indices (DBH, MHT, ABI, CDE, NOT) were calculated through tree measurement and positioning. Soil carbon storage SSTO, amylase AAM, cellulase ACL, microbial biomass carbon MBC, and soil pH were obtained through field sampling and laboratory experiments.