As global climate change and urban issues worsen, increasing carbon offsets is crucial, with urban plants playing a key role. However, research on assessing plant carbon sequestration (CSE) capacity at the regional scale, selecting urban plants, and optimizing CSE capacity-based scenarios is still limited. A total of 272 plant species were surveyed in the nine cities of the Zhengzhou Metropolitan Area (ZMA). The i-Tree and biomass models estimated the average carbon storage (CS) density at 9.32 kg C m⁻² and the CSE density at 0.55 kg C y⁻² m⁻² in the ZMA. The highest CS density (13.58 kg C m⁻²) was observed in Pingdingshan, while the lowest CSE density (0.36 kg C y⁻¹ m⁻²) was observed in Xuchang. Hierarchical and cluster analyses identified plant species with balanced CSE capacity, adaptability, and ornamental value, such as Populus tomentosa Carr. and Salix babylonica L., as well as shrubs like Abelia biflora Turcz and Kerria japonica (L.) DC. Vegetation regeneration modeling indicated that CS could increase by 37%–41% along roads, 28%–43% in amenity areas, and 17%–30% near waterfronts over the next 50 years. These findings serve as a reference for urban regeneration and planning aimed at enhancing the carbon reduction potential of urban green spaces (UGS).

Cities are major contributors to global carbon emissions; however, urban parks offer substantial potential for carbon sinks. Research on factors influencing carbon capture in urban park vegetation is still limited. This study investigates 81 urban parks in Xinyang, Henan Province, to quantify woody plant carbon storage (CS) and sequestration (CSG). By surveying all vegetation types and quantities in these parks, along with factors like park attributes, community structure, biodiversity, spatial distribution, woody plant connectivity, and spatial complexity, we create statistical models for CS and CSG. The results indicate that the average carbon storage density (CSD) in Xinyang’s urban parks is 4.01 kg/m², while the carbon sequestration density (CSGD) is 0.39 kg·C·m²·yr⁻¹. The dominant tree species are Ligustrum lucidum, Osmanthus fragrans, and Lagerstroemia indica, while species with higher carbon sequestration potential, such as Glyptostrobus pensilis, Populus deltoides, and Albizia kalkora, reveal a discrepancy between common and high-sequestration species. The study shows that park characteristics, community structure, and biodiversity are key factors impacting urban carbon sink capacity. By analyzing the relationship between these factors and carbon sinks in urban park vegetation, we create a comprehensive framework for assessing tree CS and CSG, offering quantitative support to improve carbon capture in urban parks.