Fine root morphology, anatomy and tissue nitrogen and carbon contents of the first five orders in four tropical hardwood species in Hainan Island, China The Response of Photosynthetic Characteristics and Enzymatic Antioxidant System in Leaves of Two Tropical Seedlings Growing in Shade Conditions as Temperature Fall PHENOSPECTRUMS FOR 18 SPECIES OF TROPICAL WOODY PLANTS IN JIANFENGLING, HAINAN PROVINCE Study on Phenology of Some Tree Species Grown in the Tropical Arboretum at Jianfengling of Hainan lsland