An analysis of vegetation cover and species diversity of roadside vegetation in southern section of Tanggula Mountains along the Qinghai-Tibet Railway

1 Key Laboratory of Tree Breeding and Cultivation of State Forestry Administration，Research Institute of Forestry，Chinese Academy of Forestry，Beijing，100091，P.R.China； 2 Department of Landscape Architecture and Horticulture，Temple University，Ambler，PA, 19002，USA； 3 Demonstration Base of Forestry Seedling Science & Technique in Tibet Autonomous Region，Lhasa，850000，P.R.China.