Mega-cities dominate China's urban greening
Xiaoxin Zhang Martin Brandt Xiaoye Tong Xiaowei Tong Wenmin Zhang Florian Reiner Sizhuo Li Feng Tian Yuemin Yue Weiqi Zhou Bin Chen Xiangming Xiao Rasmus Fensholt
Trees play a crucial role in urban environments, offering various ecosystem
services that contribute to public health and human well-being. China has
initiated a range of urban greening policies over the past decades, however,
monitoring their impact on urban tree dynamics at a national scale has proven
challenging. In this study, we deployed nano-satellites to quantify urban tree
coverage in all major Chinese cities larger than 50 km2 in 2010 and 2019. Our
findings indicate that approximately 6000 km2 (11%) of urban areas were covered
by trees in 2019, and 76% of these cities experienced an increase in tree cover
compared to 2010. Notably, the increase in tree cover in mega-cities such as
Beijing, and Shanghai was approximately twice as large as in most other cities
(7.69% vs 3.94%). The study employs a data-driven approach towards assessing
urban tree cover changes in relation to greening policies, showing clear signs
of tree cover increases but also suggesting an uneven implementation primarily
benefiting a few mega-cities.