Tropical cyclones impact soil particulate and mineral-associated organic carbon with variation among different forest restoration models

Aims: Forest soil organic carbon (SOC) accounts for 39% of total SOC pool and is influenced by tropical cyclones. Tropical cyclone-induced pulse effects on SOC fractions may trigger positive carbon-climate feedback. Although changes in cyclone-induced aboveground processes have been well-demonstrated, the short-term impact of tropical cyclones disturbances on forest SOC fractions remains unknown. Methods: To fill this gap, we investigated the dynamics of particulate organic carbon (POC) and mineral-associated organic carbon (MAOC) in the topsoil within four forest restoration models on the southeast coast of China during tropical cyclone Hinnamnor (2022–09-04). Results: One day after the tropical cyclone, the POC concentration substantially increased by 7.68%, 11.79%, 16.68%, and 21.19% in the bamboo forest, secondary broadleaf forest, Chinese fir plantation, and mixed conifer-broadleaf forest, respectively; and recovered to the pre-tropical cyclone values from the 5th day till the 30th day. A similar pattern to POC was found in soil microbial biomass carbon, microbial quotients, and the activities of cellulase, peroxidase, and polyphenol oxidase, which responded shortly to the tropical cyclone disturbance, except for beta-glucosidase. Regardless of forest restoration models, the tropical cyclone disturbance had a slight effect on the concentrations of SOC and MAOC. The tropical cyclone produced a significant pulse of green leaves that significantly reduced the stability of SOC. A structural equation model (SEM) indicated that soil traits and microbial properties were the primary intermediate regulators of these processes. Conclusions: These results contribute to the understanding of the dynamics of different forest SOC fractions caused by tropical cyclones.