COMPARATIVE STUDY OF PHYTOCOENOLOGY CHARACTERISTICS OF NATURAL CASTANOPSIS CARLESII FOREST AND C. CARLESII PLANTATION IN SANMING,FUJIAN A Phytocoenological Study on Dracontomelon macrocarpum Community in Xishuangbanna A Phytocoenological Study on Vatica guangxiensis ( Dipterocarpaceae) Community in Mt. Maocaoshan, Xishuangbanna