Eucalyptus Trees

The characteristic fresh fragrance of Australian eucalypt forests comes from the leaves releasing some of their eucalyptus oil.

Eucalypts form about three quarters of the tree flora of Australia.

There are over 600 species of eucalypts and all have eucalyptus oil in their leaves. The quantity and type of eucalyptus oil varies from species to species.

All eucalyptus oils are not the same.  The oil from each species has different constituents and chemical composition. However eucalyptus oil from the same species is usually remarkably constant in its constituents and chemical composition.

Only about 20 species of eucalypts have been found to have enough oil of economic value to be produced commercially. At the present time less than ten species account for the entire world production.

As a general rule good oil producing species are of little use as timber whereas those utilised for timber contain very little oil.

Eucalypts are widely distributed over the Australian continent. They range from the dwarfed and stunted forms called ‘mallees’ to the tall trees which grow in coastal and mountainous regions.

Eucalypts are typically native to Australia although a small number of species have been found in neighbouring countries. Contrary to popular belief the extensive plantations in North and South America, Europe, Africa, China and India are not native but were all grown with seeds from Australia.

The eucalypt belongs to the Myrtaceae family. The genus was named Eucalyptus by the Frenchman L’Heretier in 1788.   The word came from the Greek eu ‘well’ and kalypto ‘I cover’ and refers to the cap that covers the flower buds until the buds mature and force the cap open.

 

Why are eucalyptus trees called ‘gums?’

Ever wondered why eucalypts are often called ‘gums’? In 1688 William Dampier noted that trees in north west Australia exuded a type of gum. Aborigines used this gum to fasten barbs to the ends of spears and fishing sticks. The exudation from the bark which looks like a ‘gum’ is actually a tannin-like substance known as ‘kino’. Governor Arthur Philip is credited with being the first to call the eucalypt a ‘gum tree’ in 1788. Since then most Australians have called eucalypts ‘gum trees’. There is nothing more Australian than a ‘gum tree’!

 

Did you know...? Eucalyptus scent beats chocolate cravings, says new study.

Those who experience ‘pathological’ cravings find them constant and debilitating and may be at risk of serious health problems, according to new Australian research.

Psychology researcher Dr. Eva Kemps and colleague Dr. Marika Tiggeman examined the psychology of food cravings and found the use of counter-visualisation - in particular, imagining the scent of Eucalyptus Oil - was highly effective in curbing cravings.

Kemps, from Adelaide’s Flinders University, conducted a series of experiments in which chocolate cravings were induced in participants who were then asked to perform a series of tasks.  When they were asked to imagine the smell of eucalyptus oil, the chocolate cravings disappeared.

Source: A Cognitive Experimental Approach to Understanding and Reducing Food Cravings, E. Kemps and M. Tiggemann, 
Current Directions in Psychological Science 2010 19: 86.

The online version of this article can be found at: http://cdp.sagepub.com/content/19/2/86