Funding for this research was provided by:
Fundamental Research Funds for the Central Universities of China (2015ZCQ-SW-04)
Beijing Forestry University Innovation and Entrepreneurship Training Program for College Students (S201610022053)
Beijing Science and Technology Innovation Base Cultivation and Development Projects (IG201710C1)
Article History
Revised: 14 February 2019
Accepted: 17 February 2019
First Online: 28 February 2019