Response of Soil Microbial Community in Different Forest Management Stages of Chinese fir Plantation

Abstract

The cultivation of Cunninghamia lanceolata (Lamb.) Hook. (Chinese fir) plays a crucial role in enhancing ecological security through water resource preservation and carbon sequestration in China. The biotic and abiotic environmental conditions vary across different stages of plantation, thereby influencing soil nutrient levels and microbial dynamics. However, the interconnection between the soil nutrient cycle and microbial communities within Chinese fir plantations throughout their entire life cycle remains inadequately understood. In this study, conducted across various management stages of Chinese fir plantations in China (including the juvenile stage, first thinning stage, second thinning stage, mature stage, and over-mature stage), we examined the associations among soil organic carbon, soil physicochemical properties, soil enzyme activities, and soil microbial dynamics. Our results revealed that forest management practices significantly modify soil physicochemical properties and enzyme activities across all management stages. Specifically, the concentrations of total soil carbon, soil organic carbon, and soil microbial biomass carbon were notably higher in the over-mature stage compared to other management stages. At the genus level, the five highest contributors belonged to Subgroup2, AD3, Xanthobacteraceae, Elsterales, and Acidobacteriales for the bacterial community. For the fungal community at the genus level, the five highest contributors belonged to Ascomycota, Serendipita, Saitozyma, Mortieralla, and Venturiales. Moreover, anthropogenic thinning activities during the management phase substantially altered both stand and soil environments, as well as the structural characteristics of soil microbial communities. Soil cellulase, soil electrical conductivity (EC), and soil available phosphorus (AP) emerged as key factors influencing the relative abundance of major fungal communities, whereas soil total nitrogen, EC, and AP were identified as critical factors affecting the relative abundance of major bacterial phyla. More microbiological groups increased significantly in the juvenile stage and over-mature stage. Our findings elucidate the intricate relationships between the soil nutrient cycle and soil microbiological dynamics across various forest management stages within Chinese fir plantations.