Multi-path inhibition mechanisms of soil respiration in Pinus koraiensis plantations under wind speed regulation

This study examines how wind speed affects soil respiration in Pinus koraiensis plantations in eastern Liaoning's mountains, using high-frequency monitoring data to improve carbon cycle models and soil carbon management. The correlation analysis, XGBoost models, and structural equation modeling were employed to disentangle the direct physical effects and indirect microenvironmental regulation of understory wind speed on soil respiration, as well as nonlinear interactions with soil moisture. The results demonstrated that soil respiration exhibited significant diurnal variation, showing a humped relationship, and declined markedly from late summer to early winter. The wind speed showed a strong negative correlation with soil respiration rate, with a path coefficient of -0.198, independently explaining 7.9% of environmental factor variation. The wind speed-soil moisture interaction significantly altered respiration patterns: under high wind speeds (>0.8 m/s), soil moisture’s promotive effect on respiration weakened by ~14.5%. Wind speed suppressed respiration via dual pathways: directly enhancing soil CO₂ ventilation (path coefficient: -0.127) and indirectly reducing microbial activity by lowering soil moisture (path coefficient: -0.071). This study establishes a multi-path respiration model incorporating wind speed for temperate plantations, demonstrating that wind speed inhibits soil carbon release through synergistic physical transport and biological effects. Global wind speed decline may enhance annual carbon accumulation in plantation soils. These findings provide a scientific basis for developing wind speed-regulated forest carbon sequestration technologies.