The Study On Architecture Of Main Tropical Tree Seedlings In Hainan

Study on Architecture of Main Tropical Tree Seedlings in HainanRen Yanlin (Ecology) Directed by Dr. Li Junqing18 main tree species in tropical montane rain forest were selected, and tree seedlings of different stages were observed systematically in order to find out their architectural features. Those tree seedlings were chosen considering the importance of the species among the tropical montane rain forest community, the function during the process of forest gap regeneration, and amount of different species in the nursery. Seedlings less than 3 months and seedlings between 3 months and 26 months were described by different indicator systems.Architectural features of tropical tree seedlings of main architectural models were summarized and compared. The results of different tree species at the same stage indicated that most of the tropical seedlings are epigeal, leafy and opposite; alternate primary leaves are in the majority and opposite and whorled ones come next. Seedlings with branching angle of 30皁r 60皃redominate and those with branching angles of 45皁r 75癱ome next in the nursery. The relationship between stem height under branch and seedling height of the trees among the samples was exponential, and the relationship between seedling height and base diameter fits the power equation.A series of seedlings data of Dacrydium pierrei, Ilex goshiensis, Psychotria rubra, Alniphyllum fortunei and Ehretia longiflora showed their difference at every certain developing stage. The process from germination to mature was illustrated with figures and the seedling morphological dynamics were described in detail.The relationships among architecture, environmental factors, forest gap succession, ecological strategy and plant community structure were discussed. Solar radiation, water, soil are key factors to vegetative architecture, especially to the seedlings. Architectural variation will occur according to the environmental changes. The roles of every architectural model are different during the course of the gap regeneration, which are closely connected with their ecological strategy and surrounding community structure. Generally tropical trees of Rauh's model and Massart's model take K strategy; Leeuwenberg's model and Attims model take r strategy; while Roux's model and Aubreville's model seems apt as a compromise between K and r strategies.