SEEDLING SURVIVAL AND GROWTH OF NINE LATE-SUCCESSESIONAL SPECIES ACROSS A TOPOGRAPHIC GRADIENT IN SINHARAJA RAIN FOREST

Abstract

Growth performance of seedlings belong to nine late-successesional canopy treespecies was studied at three different topographic positions (ridgetop, midslopeand valley) in the Sinharaja rain forest, southwest Sri Lanka. Seedlings wereplanted in plots located in valleys, midslops and ridgetops. In each site fourcanopy openings and four adjacent understoreys were selected to plant seedlingsof nine late-successional canopy tree species. Seedling growth and mortality weremonitored for three years.

Results demonstrated that a clear difference in survival and growth amongspecies. These differences appeared to be related to the availability of soilmoisture and groundstorey radiation regimes of the forest. SIlOrea distichaexhibits high growth rate than others in each topographic position in each site.Seedlings of Mesua ferrea and Shorea megistophylla exhibit a higher survivalthan other species in canopy openings and understorey conditions of alltopographic positions. Growth performance and survival of their species will bemonitored for several years to study the nich specialization of the latesuccessionalcanopy tree seedlings