Funding for this research was provided by:
National Natural Science Foundation of China (31270746)
Agricultural and forestry work committee of China graduate degree and education association approved the important research project (2019-NLZX-ZD15)
Case base of professional degree postgraduate courses General project of Nanjing Forestry University (2018AL07)
Article History
First Online: 19 October 2019
Compliance with ethical standards
:
: The authors declare that they have no conflict of interest.