Optimizing Urban Green Spaces for Vegetation-Based Carbon Sequestration: The Role of Landscape Spatial Structure in Zhengzhou Parks, China

Urban parks serve as essential carbon sinks in cities, mitigating climate change by sequestering atmospheric CO2. Maximizing the carbon sequestration potential within constrained urban spaces is a critical step toward carbon neutrality. However, few studies have systematically examined how the internal spatial composition and shape of green spaces affect their vegetation carbon sequestration capacity. This study analyzes the relationship between landscape indices and vegetation carbon sequestration density (VCSD) using field surveys and high-resolution remote sensing data from 123 urban parks in Zhengzhou, China. The results indicate that Zhengzhou’s parks sequester 14.03 Gg C yr−1, with a VCSD of 0.53 kg C m−2 yr−1. Significant differences in VCSD were observed among park types, with theme parks having the highest average VCSD (0.69 kg C m−2 yr−1) and community parks the lowest (0.43 kg C m−2 yr−1). The key drivers primarily consist of landscape indices that characterize green space distribution and configuration, including the proportion of green space (Pg), largest green patch index (LPI), number of green patches (NP), green patch dispersion index (SPL), and landscape shape index (LSI), with specific thresholds identified for each. Based on these findings, category-specific spatial composition strategies are proposed to precisely enhance the carbon sequestration of park vegetation. This study provides actionable guidance for urban park designers to maximize the carbon sequestration potential of green spaces, thereby mitigating climate change and promoting human health and well-being through green space design.