Enhancing Soil Properties and Soil Microbial Diversity: Strategies for Rehabilitating Degraded Forest Ecosystem Functions

Background and aim Large areas of forests lost their ecological functions due to historical forest management with the objective of maximizing timber production. Historically, restoration studies are often focused on aboveground tree composition and impacts of restoration treatments on soil microorganisms, vital for nutrient cycling and ecosystem resilience, remains unclear.Methods We studied the impacts of different treatment intensities on both aboveground and belowground components as one system in a degraded natural mixed forest. Each treatment encompassed the analysis of plant diversity indices, soil properties, microbial activity, and microbial communities.Results Thinning treatments significantly impacted understory plant diversity and soil properties compared to the control group. Soil properties improved with increased treatment intensity, peaking at 30%, and then declined. Soil microbial biomass increased at low treatment intensity, peaked at 20%, and then declined. Treatment intensity increased the richness of soil microbial communities, peaking at around 25%. Current data suggest that treatment intensities between 20% and 30% are optimal for restoring degraded forests, enhancing both soil properties and microbial diversity. Thinning treatments indirectly modulated soil microbial diversity through the effects of plants and soil characteristics, significantly influenced by total and available phosphorus. Soil properties and microbial activity were key to explaining variations in soil microbial communities.Conclusion This study suggests that treatment intensities ranging from 20% to 30% provide the optimal balance for restoring degraded forests. Soil properties and microbial activity are crucial for understanding variations in soil microbial communities, underscoring the interconnectedness of components within forest ecosystems during restoration.