abstract the chemical composition of the essential oils from the leaves of araucaria heterophylla (also known as norfolk island pine), casuarina cunninghamian, eucalyptus citriodora, psidium cattlenium var. lucidum (also known as strawberry guava), and litters of the first two species were studied using two gas chromatography techniques, one equipped with a mass spectrometer detector (gc/ms) and the other with a fame ionization detector (gc/fid). six volatile compounds were identified in the leaf oil of a. heterophylla. a substantial increase in the amount of -pinene, -terpinene and a decrease in the amount of -caryophyllene was noticed in the litter oil of a. heterophylla. three volatile compounds were identifed in c. cunninghamian. another monoterpene, -terpinene, was observed in the litter oil of c. cunninghamian. eleven compounds were identified in the leaf oil of p. cattlenium, of which -caryophyllene (59.0%), -pinene (13.2%) and myrcene (11.3%) were the major components. thirteen volatile oil compounds were identified in the e. citriodora leaf oil, of which citronellal (42.8%), citronellol (17.9%) and -terpinene (11.2%) were the major components.