Progress and prospect on urban green space research

With rapid socioeconomic development, the effect of urban green space on the ecological environment and living environment in cities has attracted increasingly more attentions. Meanwhile, due to the expansion of built- up areas, urban green space is becoming a scarce resource. A spatial mismatch exists between the supply and demand of urban green space because the quantity and quality of green space in urban centers fall short of meeting the increasing demands of the growing urban population for recreation and good health. Therefore, the planning, design, utility, and function of urban green space have become an important area of urban geography research and urban planning practice. Drawing on the recent progress in research, the paper introduces the concept of urban green space and its evolution. It also synergizes the literature of various disciplines to produce a systematic understanding of the role of urban green space in promoting ecological services, social life,and economic value of land. Main challenges include: the lack of policy and measures for effectively incorporating green space into urban spatial development, inadequate treatment of improving the quality of urban green space, and mismatch between the supply and demand of the urban green space. Therefore, we argue that green space is another important urban space other than economic and social ones. This important topic in urban geography raises new but important issues:(1) incorporating urban green space as a way of enhancing urban sustainability;(2) improving current urban planning by emphasizing the social, economic, and ecological functions of cities;(3) extending the horizon and topics from traditional descriptive research on the distribution and spatial characteristics of urban green space to look at the interaction between green space and socioeconomic development; and(4) urban geography should play a role in synergizing and facilitating multi- disciplinary research on urban green space, but needs both quantitative and qualitative methods.