Evaluating Biomass and Carbon Stock Responses to Thinning and Pruning in Mature Larix principis-rupprechtii Stands:A Case Study from Northern China

Forestry management operations significantly influence biomass accumulation and carbon sequestration,essential factors for climate change mitigation.The study focuses on the 50-year-age Larix principis-rupprechtii Mayr plantations at Saihanba Mechanical Forest Farm,Northern China,assessing how varying intensities of thinning and pruning influence biomass and carbon stocks.The experimental design included 45 plots subjected to 15 treatments having a combination with five thinning(T0:0%,T1:10%,T2:20%,T3:30%,T4:35%)and three pruning intensity levels(P0:1:2,P1:1:3,P2:2:3),with comprehensive assessments of aboveground biomass(AGB),belowground biomass(BGB)and Total Biomass.The statistical significance of differences between treatment groups was assessed using Analysis of Variance(ANOVA).Regression analysis was used to explore the relationships between silvicultural treatment intensities and forest growth responses.This involved fitting linear models to predict forest metrics(dependent variables)from treatment intensities(independent variables).Results indicate an apparent reduction in AGB,BGB,and total biomass with increasing thinning intensity,showing a decrease in AGB and BGB by up to 42.13%and 42.57%compared to the control treatment.The percentage decrease in total biomass from the control treatment,T0P0,to the most intensive treatment,T4P2,is approximately 42.44%.The percentage decrease in total carbon over the same treatments is about 44.18%.The soil organic carbon(SOC)decreased by 35.56%compared to the control treatment.Pruning influences tree structure and health.The findings highlight the complex interactions between forest management practices and carbon dynamics.They underscore the adoption of light,moderate thinning,and light,pruning strategies,which can sustain the forest's carbon sequestration capabilities while maintaining forest health and productivity.This study provides empirical evidence to guide future forest management decisions,emphasizing the critical balance needed to maximize forest health and carbon sequestration potential.