Abstract: Climate change is one of the hotspots in global environment concerns,while alpine tundra ecosystem is most sensitive to global climate change.Because of the relatively small area of tundra,researches on alpine tundra ecosystem were much less.Based on the measurement of species biomass,dominant species organ biomass and vegetation biomass,this paper discussed the biomass spatial variation in alpine tundra ecosystem of Changbai Mountains.The results showed that among 43 species investigated,the first five species in biomass were Rhododendron chrysanthum(159.01 kg穐m^-2),Vaccinium uliginosum var.alpinum(137.52 kg穐m^-2),Vaccinium uliginosum(134.7 kg穐m^-2),Dryas octopetala var.asiatica(131.5 kg穐m^-2) and Salix rotundifolia(128.4 kg穐m^-2),which were the dominant species in the alpine tundra ecosystem of Changbai Mountains.Along with increasing altitude,the ratio of below-/above-ground biomass and below-ground/total biomass gradually increased,while the vegetation biomass gradually decreased.The vegetation biomass showed a significant correlation with altitude in typical alpine tundra ecosystem of Changbai Mountains,and the average vegetation biomass was 2.21 t穐m^-2 .Alpine tundra ecosystem is very important for microclimate regulation,soil improvement,water-holding,soil conservation,nutrient cycling,carbon fixation and oxygen production,and currently,it is the CO₂ sink of Changbai Mountains.

Key words: Alpine tundra, Biomass, Changbai Mountains