Australian Geographic — May-June 2017

OIL

ESSENTIALS

Australia’s essential oil industry,

based largely on compounds that

produce the ‘aroma of the bush’,

continues to grow annually.

Today our most successful

essential oil is

tea-tree oil.

In November 1788 1L of

steam-distilled oil from

leaves was sent to England

by John White,

surgeon-general to the colony:

reportedly the first useful natural

product sourced from Australia.

Sydney peppermint gum

Each year up to 900 tonnes

of pure Australian tea-tree

oil are produced and in

2015–16 a total of

was exported around the globe.

620 tonnes

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May. June 93

with a citrus smell. Aromas come up in diagnostic keys

published in journal articles, for example, to tell one daisy

bush from another. In lilly pillies (rainforest plants that are

part of the same family as the eucalypt), the density of oil

glands is one feature used to separate allied species.

H

UMANS CAN REPORTEDLY identify 700 different

odours, but that’s nowhere near as good as it

sounds. We have more trouble putting names to

familiar scents than to sights and sounds. The areas of the

brain responsible for classifying smell and language don’t

have strong connections, leaving us without a good vocab-

ulary for smells or an accepted classification system.

This shows through in the inconsistent descriptions of

some plants. Sprouting along river flats in coastal New

South Wales, for example, the odd-looking incense plant

(Calomeria amaranthoides) has a smell often likened to

bananas, hops and incense, three items that don’t smell

alike. Chocolate lilies have a delicious scent similar to

vanilla, caramel and chocolate, and I am never sure which

descriptor fits best. One fungus has a smell that compares

with iodine and aniseed. In the same way, wine is described

by critics using words such as buttery, earthy, fleshy and

jammy, none of which make much literal sense.

A multitude of

oil-filled glands

shows why the oil

mallee is a valued

source of eucalyptus

oil, rich in highly

aromatic cineole.

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This Bosisto

Parrot Brand

Eucalyptus Oil label

is from 1871 but the

product is still sold

today to help relieve

cold symptoms.

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PHOTO CREDITS, FROM LEFT: SHUTTERSTOCK; STATE LIBRARY OF VICTORIA. SCIENTIFIC NAME:

Eucalyptus

kochii