Simultaneous flowering caused a gregarious dieback of umbrella bamboo (Fargesia murielae) all over the world in 1993-2000. Mountain Shennongjia in Central Chinas Hubei Province is the only native home of umbrella bamboo, where it dominates the understorey of the farges fir (Abies fargesii) forest between 2 400 and 3 100 m, covering the ground for more than one century before a periodically flowering death. Data from 20 quadrats along a vegetation sequence revealed that the density, coverage, and height of umbrella bamboo negatively affected the species richness, diversity, and evenness of vascular plants in the forest. Local climax community of fir-bamboo was the poorest in species diversity, while the bamboo-free communities (i.e. shrubs and meadows) were bearing a higher species diversity. The simultaneous dieback of umbrella bamboo is an ecological release, which can periodically promote the plant diversity in the fir forest.