Research on the Spatial Evolution and Planning Strategies of Green Belts in Metropolises

Green belts in metropolises face a significant contradiction between ecological protection constraints and urban sprawl, necessitating effective planning and management. Existing studies have primarily focused on a single dimension, while the factors influencing the spatial evolution of green belts are complex and diverse. This study establishes a multi-objective quantitative analysis framework, utilizing quantitative analysis methods such as average nearest neighbor analysis, landscape ecological index analysis, land–use transition matrix, kernel density estimation, and spatial autocorrelation models. Taking the green belt area of Shijiazhuang as a case study, this research systematically analyzes the spatial evolution characteristics of the region from 2015 to 2024. The findings reveal spatial patterns such as the small-scale and dispersed expansion of industrial land, increasing fragmentation of ecological spaces, ongoing encroachment on agricultural land, differentiated growth of service industry spaces, and the uncontrolled sprawl of residential areas in villages and towns during rapid urbanization. These patterns lead to increased ecological risks, imbalanced urban–rural development, and lagging infrastructure. To address these challenges, this study proposes a planning strategy of “adjusting the primary industry, restricting the secondary industry, and promoting the tertiary industry,” aiming to resolve the conflict between ecological protection and urban expansion in metropolitan green belts, ensuring their orderly development. This research provides insights for the sustainable development of green belts in Metropolises of developing countries during the rapid urbanization process.