Abstract: The decomposition of woody debris is an important part of the forest carbon cycle, and microorganisms are the key factor influencing its decomposition rate. In recent years, the mechanisms of microbial community building in woody debris have gradually become an important topic in the study of carbon cycling in forest ecosystems. However, current microbial research on woody debris is fragmented. Hence, this paper reviews the formation mechanism of woody debris microbial communities. 1) Microorganisms maintain a dynamic balance of communities by continuously colonising woody debris. The microbial sources of woody debris mainly stem from the debris itself, the atmosphere and the soil. The colonization process occurs at all stages of decomposition and consists mainly of competition and resource capture that occurs when microorganisms colonizing the substrate. 2) Soil, properties of woody debris and climate are three important factors influencing the formation of microbial communities of woody debris, all of which act on the microbial sources and the colonisation process. 3) The soil environment affects the soil microbial community and changes the properties of the debris with which it comes into contact. Differences in woody debris properties affect the availability of resources and thus the microbial community. As decomposition proceeds, microbial community assembly changes from an initial dominance of stochastic processes to a dominance of deterministic processes. Climate affect the soil and woody debris through both temperature and humidity climate factors, mainly in the form of macroclimate, microclimate and global climate change. Finally, the paper summarised the issues that need to be addressed in future research in this area and identifies the need to: 1) focus on the impact of early colonizers and soil microorganisms at different stages of decomposition on the microbial community of woody debris; 2) strengthen the study of changes in woody debris resources and the function of the dominant species in the corresponding microbial community; 3) link woody debris decomposition to global climate change and nutrient cycling; 4) select more precise techniques for the decomposition of woody debris. In summary, this paper summarised the basic ideas, framework and prospects for the study of microbial community formation mechanisms in forest woody residues, providing certain scientific references for forest biodiversity conservation, maintenance of biogeochemical cycle functions and forest carbon sequestration.

Key words: forest ecosystem, microflora, woody debris, soil, decomposition, climate change