Exploring the effects of urban spatial structure on green space in Chinese cities proper

The process of urbanization has led to the agglomeration of population in cities and the transformation of rural landscapes into impermeable surfaces, leaving green spaces severely eroded. Agglomeration is the essence of cities, and optimizing the spatial structure can preserve green space in cities. In urban planning practice, the most common urban spatial structures are monocentric and polycentric. It remains unclear whether monocentric structure with high-density attributes or a polycentric structure with decentralization has better green space performance. This study examines the effects of monocentric and polycentric urban spatial structures, as measured with the dimensions of spatial centralization and concentration, on the size and accessibility of green space in Chinese cities proper at the prefecture level and above from 2000 to 2015. Using a panel dataset and instrumental variable techniques, we observed that, under equal conditions, urban green space can be improved when cities proper have a compact monocentric structure. However, the accessibility of green space is better when cities proper have polycentric structures. These findings are robust across various specifications and instruments. Optimizing the urban spatial structure can increase the size of and accessibility to green space in cities. This is important for urban air purification, microclimate regulation, and residents’ recreation and happiness. Our results provide guidance for policymakers seeking to optimize urban spatial structures and develop green cities.