EDAPHIC INFLUENCES ON TREE SPECIES COMPOSITION AND COMMUNITY STRUCTURE IN A TROPICAL WATERSHED FOREST IN PENINSULAR MALAYSIA

Abstract

KHAIRIL M, WAN JULIANA WA & NIZAM MS. 2014. Edaphic influences on tree species composition and community structure in a tropical watershed forest in Peninsular Malaysia. A study was conducted to determine tree species composition and community structure, and their relationships with edaphic factors at a watershed forest in Tasik Chini, Peninsular Malaysia. Thirty plots of 0.1 ha were established with a total sampling area of 1.4 ha in inland forest, 0.9 ha in seasonal flood forest and 0.7 ha in riverine forest. A total of 3974 trees with diameter at breast height (dbh) ≥ 5.0 cm were recorded. The inland forest recorded 2061 individuals representing 393 species from 164 genera and 57 families; the seasonal flood forest had 1019 individuals representing 268 species from 137 genera and 57 families; and the riverine forest had 894 individuals representing 260 species from 137 genera and 53 families. Endospermum diadenum (Euphorbiaceae) was the most important species in the inland forest with importance value index (SIVi) of 3.36%, Streblus elongatus (Moraceae) in the seasonal flood forest with SIVi of 4.43% and Aporusa arborea (Euphorbiaceae) in the riverine forest with SIVi of 2.96%. The pH values of all three types of forest soils were acidic, with readings between 4.0 and 4.1. The highest average organic matter was in the inland forest (9.30%), followed by the riverine forest (8.49%) and seasonal flood forest (7.84%). The highest available P and K were in the riverine forest with values of 14.27 ± 1.23 and 175.88 ± 27.95 meq/100 g respectively. Ordinations using canonical correspondence analysis showed that the relationships between tree community and soil properties were weakly associated (p > 0.05). However, there were some species that were highly correlated with soil chemical characteristics and organic matter content.