tasmanian blue gum (Eucalyptus globulus subsp. globulus)
This classic Tasmanian eucalypt is the State’s floral emblem. Blue gum grows from a tiny seed ejected from its characteristic large single ‘gum nuts’ during summer. Its blue juvenile (young) leaves grow opposite each other on the stem, and develop into glossy dark green long, slender adult leaves. Blue gum blossoms are large and cream-coloured, and produce copious amounts of nectar.
The hard, close-grained wood of the blue gum made spears for Aboriginal Tasmanians, while its thick bark was used to make canoes. Aboriginal people also used the liquid residue from boiled leaves for drinking or rubbing on their body to treat chest colds, and inhaled its odours for headaches. Blue gum leaves were also used in poultices for wounds, inflammation and rheumatism, and the sugary white residue of dried sap oozing from the trees made a sweet food.
Today's timber industry places a high value on blue gum timber - it yields pale, hard and durable wood for poles, piles and sleepers. It has also been used for paper pulp and firewood, and its pollen and nectar is food for honeybees. Blue gum eucalyptus oil is used as an insecticide, a decongestant, a deodorant, and for antifungal and antibacterial use. It is also a food flavouring and a cosmetics fragrance.
Taroona's eucalypts are too large for most suburban blocks, which is why protecting them in our foreshore, gully and school bushland reserves is so important - as is nurturing the next generation of gums. Loss of mature gums significantly reduces the overall biodiversity of Taroona.
Loss of blue gums and black gums in particular, also threatens the survival of the nationally endangered swift parrot. These migratory birds spend autumn and winter in Victoria and New South Wales, and arrive in Tasmania during spring to breed in the hollows of mature blue or black gums. They also feed solely on the nectar from these trees' flowers.
As well as the nectar being critical food for swift parrots, blue gums are a source of food, shelter and accommodation for a great variety of other wildlife. Brushtail and ringtail possums feed on leaves and flowers and sleep and nest in tree cavities, and bandicoots find invertebrates in the leaf litter. Many birds use blue gums - yellow wattlebirds, musk lorikeets, rosellas, honeyeaters and pardalotes.
(photos: Richard Barnes and Fiona Rice)
STUDENT INQUIRY QUESTIONS
Crush a eucalypt leaf and smell its oil. Why do they have oil inside their leaves?
Look carefully on and around a mature blue gum. How many different kinds of animals can you find living on it, or visiting to feed? (Look for the tiny insects too.)
Why is it so important to protect Taroona's blue gums - especially old blue gums?