Acknowledgements
This work was partially supported by National Key R &D Program of China (2017YFA0604802 & 2016YFC0500703) and the National Natural Science Foundation of China [31770526, 31872406] and Key Laboratory of Vegetation Ecology, Ministry of Education, Northeast Normal University; State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences. Requests for data sharing or any questions should be directed to Dr. C.H. Wang (E-mail:wangch@ibcas.ac.cn).