Abstract: Acomparative study on the plant species in 25m×100 m plot of typical ravine rain forest and a 6 m×400 m plot of A momun plantation indicates that A momun plantation had a clear impact on the structure of rain forest. The B,C,D, and Elayers of the forest were destroyed, and 8 national protected species, i.e., Cyclobalanopsis rex and Paramichelia baillonii in layer A, Myristica yunnanensis,Horsfieldia pandurifolia, Mangifera sylvatica, and Mangnolia rostrata in layer B, Cycas yunnanensis in layer D, and Tacea chantrieri in layer Ewere disappeared. In addition, another 7 provincial protected plants could also be disappeared. The strategy for rain forest conservation is to strictly conserve the core zone on statutory requirements. The conservation of relatively centralized area of protected plants should be managed in collaboration with local villagers, and the protected plants should be kept to sunshade for planting A momun.

Key words: Amomum villosum, Key protected plants, Species disappearance, organic carbon content, altitude gradient, temperate forest, oxidoreductase, hydrolase