Net carbon balance analysis of urban parks from construction to operation: a multi-source data study in Zhengzhou

Amid global climate change and carbon neutrality targets, urban parks serve a crucial function in mitigating urban carbon emissions by facilitating carbon sequestration and moderating microclimatic conditions. Most existing studies on urban parks have focused on carbon sequestration potential, whereas relatively little attention has been paid to carbon emissions. Consequently, research on the net carbon balance of urban parks throughout their life cycle remains limited. This study integrates multi-source data, active LiDAR, and field survey data to quantify the spatiotemporal patterns of carbon sequestration and carbon emissions, and simulates the process of achieving net carbon balance in urban parks. Results indicate that the carbon sequestration density of urban parks has shown a sustained upward trend, with a notable increase in the later stages. Most parks have reached a sequestration density of 5.61–7.24 kg·CO 2 -eq·m −2 ·yr −1 . Construction-phase emissions averaged 31.71 kg·CO 2 -eq·m −2 , with 74 % attributed to building material production. Electricity-related emissions during the operational phase amounted to 2.02 kg·CO 2 -eq·m −2 ·yr −1 . Emissions from vegetation maintenance ranged from 0.77 to 1.04 kg·CO 2 -eq·m −2 ·yr −1 , depending on the intensity of management. The average time for parks to achieve carbon neutrality was between 9 and 11 years. This study also estimated the net carbon balance and applied the Shapley Additive exPlanations (SHAP) analysis to evaluate the contributions of different variables to the net carbon balance coefficient (NCBC). Among these, the floor area ratio exerted the strongest negative effect. These findings provide methodological insights and data support for carbon management and low-carbon design in urban park planning.