Huang Lei, Zhou Yunchao
College of Forestry, Guizhou University, Guiyang, 550025, China.
Guizhou Academy of Forestry, Guiyang, 550025, China.
Carbon Balance Manag. 2024 Sep 3;19(1):29. doi: 10.1186/s13021-024-00269-x.
Thinning practices are useful measures in forest management and play an essential role in maintaining ecological stability. However, the effects of thinning on the soil properties and microbial community in large Chinese fir timber plantations remain unknown. The purpose of this study was to investigate the changes in soil physicochemical properties and microbial community composition in topsoil (0-20 cm) under six different intensities (i.e., 300 (R300), 450 (R450), 600 (R600), 750 (R750) and 900 (R900) trees per hectare and 1650 (R1650) as a control) in a large Chinese fir timber plantation.
Compared with the CK treatment, thinning significantly altered the contents of soil organic carbon (SOC) and its fractions but not in a linear fashion; these indicators were highest in R900. In addition, thinning did not significantly affect the soil microbial community diversity indices but significantly affected the relative abundance of the core microbial community. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant bacterial phyla; the relative abundances of Proteobacteria and Acidobacteria were highest in R900, and that of Actinobacteria was lowest in R900. The dominant fungal phyla were Ascomycota, Basidiomycota and Mucoromycota; the relative abundance of Ascomycota was lowest in R900, and that of Mucoromycota was highest in R900. The fungal microbial community composition was more sensitive than the bacterial community composition. The activity of the carbon-cycling genes was not linearly correlated with thinning, and the abundance of C-cycle genes was highest in R900.
These findings are important because they show that SOC and its fractions and the abundance of the soil microorganism community in large Chinese fir timber plantations can be significantly altered by thinning, thus affecting the capacity for carbon storage. These results may advance our understanding of how the density of large timber plantations could be modified to promote soil carbon storage.
间伐措施是森林经营中的有益手段，对维持生态稳定起着至关重要的作用。然而，间伐对中国大型杉木人工林土壤性质和微生物群落的影响尚不清楚。本研究旨在调查在一个大型杉木人工林中，六种不同强度（即每公顷300株（R300）、450株（R450）、600株（R600）、750株（R750）和900株（R900），以及作为对照的1650株（R1650））下，表层土壤（0 - 20厘米）的土壤理化性质和微生物群落组成的变化。
与对照处理相比，间伐显著改变了土壤有机碳（SOC）及其组分的含量，但并非呈线性变化；这些指标在R900中最高。此外，间伐对土壤微生物群落多样性指数没有显著影响，但对核心微生物群落的相对丰度有显著影响。变形菌门、酸杆菌门和放线菌门是主要的细菌门类；变形菌门和酸杆菌门的相对丰度在R900中最高，而放线菌门的相对丰度在R900中最低。主要的真菌门类是子囊菌门、担子菌门和毛霉门；子囊菌门的相对丰度在R900中最低，而毛霉门的相对丰度在R900中最高。真菌微生物群落组成比细菌群落组成更敏感。碳循环基因的活性与间伐没有线性相关性，且碳循环基因的丰度在R900中最高。
这些发现很重要，因为它们表明间伐可显著改变大型杉木人工林中土壤有机碳及其组分以及土壤微生物群落的丰度，从而影响碳储存能力。这些结果可能会增进我们对如何调整大型人工林密度以促进土壤碳储存的理解。
