Abstract: The population index of dominant species,such as number,density,age structure and distribution pattern, was conducive to evaluating the strength of community interference,determining the trend of community succession.In this paper,we systematic ouy studied the composition and density structure of dominant species of the three reaches and its six different habitat conditions of the Upstream of Wenyuhe Watershed. The results showed that:(1) the vegetation of Picea wilsonii forest reach was in the succession stages of climax community or near climax community,had minimal human disturbance,and had been in a typical zonal vegetation types;(2) If human disturbance could be avoided or reduced in Betula platyphylla reach,the riparian forests would develop to Picea meyeri forest and upland forests would stayed in the mixed coniferous stage in a very long time;(3) the riparian vegetation of farmland reach had quit basically out of natural succession,the Lair principis-rupprechtii upland forests would remain a steady-state in a long period.The paper also raised some vegetation management measures for every reach in Wenyuhe Watershed Upstream.

Key words: Wenyuhe watershed, riparian zones, adjacent uplands, dominant species, density structure