PLANT DIVERSITY AND PHYSIOGNOMY OF A TROPICAL MONTANE RAIN FOREST IN MENGSONG,SOUTHERN YUNNAN,CHINA
滇南勐宋热带山地雨林的物种多样性与生态学特征

The species composition, plant diversity, and the ecological and physiognomic characteristics of a tropical montane rain forest in Mengsong, southern Yunnan, were studied. Two main forest community types were recognized based on their habitat, species composition and forest profiles: a Mastixia euonymoides-Phoebe megacalyx community and a Parachmeria yunnanensis-Gymnanthes remota community. The montane rain forest is characterized by evergreen mesophanerophytes and microphanerophytes with simple, leathery and entire mesophyllous leaves, a relatively high abundance of woody lianas and epiphytes, abundant herbaceous phanerophytes, few buttressed trees and little or no cauliflory. Compared to the seasonal rain forests of the region and equatorial lowland rain forests, the montane rain forest has a lower abundance of mega- and mesophanerophytes and big woody lianas but a higher abundance of microphanerophytes, nanophanerophytes and herbaceous phanerophytes, and more plants with simple, leathery and non-entire leaves and microphyllous leaves. Compared with the dominant monsoon evergreen broad-leaved forests common in southern China, epiphytes and herbaceous phanerophytes are more abundant in the montane rain forest but have fewer plants with non-entire and microphyllous leaves. The montane rain forest in Mengsong can be classified as a wet tropical montane forest similar to the lower montane rain forest from tropical Asia. The montane rain forest in Mengsong has similar species diversity to the seasonal rain forest but higher species diversity than the monsoon evergreen broad-leaved forest of the region.