ACKNOWLEDGEMENTS
This work was supported by the Fundamental Research Funds of Chinese
Academy of Forestry (CAFYBB2017ZF002), National Key R & D Program of
China (2018YFC1200400) and National Natural Science Foundation of China
(31971666). We thank Dr. Rodrigo J. Mercader (Department of Biology,
Washburn University, Topeka, KS) and Dr. Andrew M. Liebhold (USDA Forest
Service, Northern Research Station, Morgantown, WV) for their critical
comments on an earlier version of the manuscript.