In the context of accelerating global climate change, the accurate quantification of forest carbon sequestration at the regional scale is of critical importance to estimate carbon budgets and formulate targeted ecological policies. This study systematically investigated the spatiotemporal dynamics and driving mechanisms of arbor forest carbon stocks between 2016 and 2020 in Yunnan Province, China. Based on the “One Map” forest resource inventory, the continuous biomass expansion factor (CBEF) method, standard deviational ellipse (SDE) analysis, and multiple linear regression (MLR) modeling, the results showed the following. (1) Arbor forest carbon stocks steadily increased from 832.13 Mt to 938.84 Mt, and carbon density increased from 41.92 to 42.32 t C·hm⁻². Carbon stocks displayed a dual high pattern in the northwest and southwest, with lower values in the central and eastern regions. (2) The spatial centroid of carbon stocks shifted 4.8 km eastward, driven primarily by afforestation efforts in central and eastern Yunnan. (3) The MLR results revealed that precipitation and economic development were significant positive drivers, whereas temperature, elevation, and anthropogenic disturbances were major limiting factors. A negative correlation to afforestation area indicated a diminished need for new plantations as forest quality and quantity improved. These results provided a theoretical foundation for spatially differentiated carbon sequestration strategies in Yunnan, providing key insights for reinforcing ecological security in Southwest China and enhancing national carbon neutrality objectives.

As a critical decision–support tool for sustainable development in alpine lake watersheds, ecosystem service valuation requires scientifically robust accounting systems to inform environmental management. This study addresses the significant interference caused by multi-source heterogeneity in indicator selection, methodology application, and parameter determination within current valuation systems. We innovatively developed a multi-dimensional accounting framework. Through establishing standardized systems for indicators, methods, and parameters, taking Xingyun Lake as the research area, we systematically elucidated the differential impact mechanisms of accounting elements on valuation outcomes. Empirical results demonstrate that structural differences in indicator systems induce 11.61% of valuation fluctuations. Methodological choices lead to 13.86% of deviations. Insufficient parameter localization generates errors up to 18.48%. The refined framework improved valuation accuracy by 16.22%. This study quantitatively evaluates the influencing factors of ecosystem services and confirms a cascading amplification effect of element sensitivity (parameters > methods > indicators) on valuation outcomes, establishing methodological foundations for alpine lake watershed ecological accounting benchmarks. It has important decision-making reference value for applying ecosystem service function evaluation to sustainable development.