Abstract: Based on the data of roof greening in urban areas of Beijing and relevant policy documents released from 2005 to 2015, the situation of roof greening in urban Beijing was clarified. The distributions of roof greening in each urban district of Beijing as well as building types were examined. Moreover, the proportion of roof greening in urban greening coverage and its annual dynamics were investigated. The promotion effect of documented policy on the development of roof greening was analyzed. The results showed that from 2005 to 2015 the total installation area of green roof in Beijing urban areas was 1.23×10⁶ m², with an annual average of 1.12×10⁵ m². Up to 2015, the sequence of accumulated area of newly constructed roof greening for all urban districts was Chaoyang > Dongcheng > Haidian > Xicheng > Fengtai > Shijingshan. Regarding the distribution of roof greening on different building types, public buildings for governmental agencies, colleges and schools, institutes, and hospitals were the main components, accounting for62.0%-80.4% of the annual total expansion area from 2011 to 2015. During this period, theproportion of roof greening in urban greening coverage increased over time, which was larger in capital functional core zone than in capital functional extension zone. However, up to 2015, roof greening took up only 0.30% of greening coverage in Beijing urban areas, indicating great potential in the future expansion of urban roof greening in Beijing. Strengthening incentive measures and promulgation of compulsory measures were suggested to promote the development of roof greening in urban Beijing.

Key words: ABA, apple, sugar metabolism, transportation., ¹³C-photosynthate