Identifying the right building roofs for greening from the perspective of socio-ecological demands in a 3D urban landscape

The multiple benefits of green roofs (GRs) for people and biodiversity conservation in a highly urbanized area are widely confirmed, however, how to identify the right building roofs in a built-up city from the perspective of socio-ecological demands to apply greening is still lacking. In this paper, with the support of the LiDAR 3D point clouds, high-resolution satellite image and socio-economic data, we proposed a systematic approach to identify and prioritize the building roofs for greening by integrating the roof physical structure attributes and socio-ecological demands on the GRs. The suitable buildings for roof greening in the central city of Nanjing, China were first specified on account of the building age and physical structure attributes e.g. height and roof slope, and the other-limited attributes e.g. protected area for historical and cultural heritage, and then a comprehensive framework for assessing roof greening priority was proposed by integrating the building attributes and the socio-ecological demands. The results showed that the total potential suitable area for roof greening is 2879.62hm², which accounts for 46.60% of all building roofs. The order of priority installing green roofs is spatial heterogeneous, and the area of high-priority level to install GRs is 629.93hm². These results can be used to guide and promote the construction of green roofs in Nanjing, and the developed comprehensive framework to identify the building roofs for greening is also broadly applicable and can be used for other cities.