The natural occurrence of oil glands in various organs such as bark and leaves is well established as a characteristic of Eucalyptus, but this is the first reported case of traumatic oil glands induced in response to wounding. The new phloem enveloping the wound, which had developed within the 2years following branch pruning in 5-year-old Eucalyptus globulus Labill., was morphologically distinct from healthy stem phloem. Histological examinations revealed this wound-associated phloem to be largely composed of secretory cavities similar in appearance to oil glands. Subsequent analysis of the wound-associated phloem extracts by GC-MS confirmed the presence of volatile terpenes and phenols. The total extracted oil content determined for wound-associated phloem extracts was significantly higher (4 times) than for healthy stem phloem extracts. A comparison of the relative abundances of ten individual terpenoids from wound-associated phloem and healthy phloem revealed a number of significant differences in terpene composition. Implications of the role of terpenes as inducible secondary metabolites in tree wound responses are discussed.