Niche characteristics of the primary understory populations of a Picea asperata plantation in the subalpine region of Gansu Province

• Yi-ming Feng, 
• Xue-long Chen, 
• Rui Qi, 
• Yang Zhao, 
• Ya-li Hou, 
• Qian-qian Yan, 
• She-qin Li, 
• De-cai Xu