Allelopathic effects of Casuarina equisetifolia extracts on seed germination of native tree species

To explore the possibility of planting the trees at later stage in C. equisetifolia forest, the effects of root, soil and litter aqueous extracts of C. equisetifolia forests of 3- ages (Young forest : 5-8 y; Middle-aged forest : 15-20 y; Mature forest: >30 y) were examined on germination of 3- native tree species (Vatica mangachapoi, Thespesia lampas, and Calophyllum inophyllum). The aqueous extracts suppressed the seed germination of above 3- native tree species and the extracts from mature forest rhizosphere soils, were most allelopathic. The inhibitory effects of extracts on C. inophyllum was weaker than on V. mangachapoi and T. lampas. The chemical componetnts in root, rhizosphere soil and litter extracts of Casuarina equisetifolia of different stages were characterized by GC-MS. The number of components found in litter and roots extracts were more than in soil extract.