The Scent of Australia: Eucalyptus oil genes for environmental management and biodiversity.

A project undertaken at the Australian National University and supervised by William Foley

Eucalypts and their relatives are the major group of trees in Australia. The scent of Eucalyptus results from the volatile oils in the leaves and buds. These oils are a mixture of chemicals called “terpenes” – some have a lemon scent, others the typical sharp eucalypt odour and yet others a distinct peppermint smell.

Eucalyptus and tea-tree oils from Melaleuca have many uses as medicines, perfumes and in manufacturing. Furthermore, much of our biodiversity depends on Eucalyptus oils through their effects on herbivores (e.g. koalas) and other ecological processes. As well as contributing to biodiversity, deep-rooted trees such as eucalypts are vital in ameliorating salinity, erosion and in improving water quality. However, the extent of re-planting needed is beyond the means of government or community organizations. We need to increase financial incentives for farmers who do the work on behalf of us all.

We aim to use the recent discovery of the genes that control the formation of Eucalyptus terpenes to better understand why different types of eucalypts and tea-trees have such different oils and to develop ways to improve the selection of trees that contain valuable oils. Making these oils more valuable will drive re-vegetation by the private sector because it provides an immediate cash return through sale of the oil throughout the life of the tree.

Figure 1. Sampling foliage from E. sideroxylon.