Assessing urban green infrastructure: A simple and practical measure of its spatial distribution equity and a comprehensive evaluation

Abstract

Urban green infrastructure (UGI) that provides diverse ecosystem services are crucial components of a city. Achieving appropriate density and equitable distribution of UGI is highly significant for urban planning to ensure sustainable and high-quality development. However, there is still a lack of an applied method for effectively measuring spatial equity of UGI in cities with multiple scales, which impairs the ability to regularly monitor it. Furthermore, the extent to which UGI should be implemented in urban planning in China is still uncertain. In this study, a “Structure-Function-Zoning“ analysis framework for the spatial pattern of UGI is proposed. A monitoring index system in terms of the structure and functions of UGI is first established. Then, an approach for measurement of spatial distribution equity of UGI is developed based on a spatial zoning strategy along the urban expansion axis. And a weighted index is proposed for comprehensive evaluation of UGI pattern. Using three Chinese cities (i.e., Beijing, Tianjin, Shijiazhuang) as examples, our research shows that the UGI pattern of Tianjin is distributed more balanced from urban center to suburb among the cities and Shijiazhuang shows relatively poor spatial equity of UGI. In terms of comprehensive evaluation of UGI pattern, Beijing and Tianjin are both rated as “moderate” while Beijing was slightly better than Tianjin, and Shijiazhuang was rated as “relatively poor”. The proposed analysis framework is designed to access the structure and function of UGI in a way that can be spatially differentiated, easily described, and clearly compared for cities of different sizes. More broadly, the comprehensive index adopted in the study can be regarded as a simple and practical tool to perform regular monitoring and provide early warning for UGI planning in urban renewal process.