1. College of Forestry, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China;
2. College of Grassland, Resources and Environment, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia, China;
3. Non-timber Research and Development Center of Chinese Academy of Forestry, Zhengzhou, Henan, China;
4. Non-Timber Forest Research and Development Center, Chinese Academy of Forestry, Zhengzhou, Henan, China