Abstract:Larix chinensis is a typical endemic species in Qinling mountain and also an endangered species listed in Chinese Plant Red Data Book. It is the only tree that forms the pure forest which has special functions to maintain the ecological balance at the timberline area, an altitude 2900m~3500m. The L. chinensis forest includes 5 associations which can indicate the different populations respectively (L. chinessis-Abies fargesii-Betula utilis-Rhododendron clementinaeas as population A; L.chinesis-Abies fargesii...