To many, Australia means kangaroos, koala bears, didgeridoos and eucalyptus trees. Without eucalyptus trees, Australia's wildlife, like the koala and kookaburra, would have trouble surviving; and, since didgeridoos-- Aboriginal instruments--are made chiefly from eucalyptus wood, the music of Australia's Aborigines might have a decidedly different sound. The stately eucalyptus has flourished in Australia's fire-prone continent for many millions of years.
Eucalyptus grows in virtually every section of Australia, including the alpine areas of Victoria, the tropics of Queensland, and the driest, most arid regions of the Outback. While all Eucalyptus may seem pretty much the same to visitors to the continent, eucalyptus "trees" come in a variety of shapes, colors and sizes. Some eucalyptus are classified as shrubs, because they are multi-stemmed and grow no higher than about three feet. Other eucalyptus are termed "mallees," which are multi-stemmed, woody plants that grow to a maximum height of about 33 feet. Still others earn the term "tree," since they grow upright from a single woody stem and branch out into various types of crowns.
Eucalyptus trees can grow to enormous heights. Indeed, the largest eucalyptus tree, dubbed Centurion, exists today in Tasmania and measures a whopping 326.8 feet high, with a diameter of 13.3 feet.
The stringy, loose bark of many eucalyptus trees sheds throughout their lifetimes and often reveals brightly colored smooth bark that soon fades to more neutral shades. The smooth, new bark of many eucalyptus trees appears as vivid reds, oranges, yellows or mellow greens.
Most, but not all, eucalyptus trees are called "stringybarks" because of the long, loose strings or curls of peeling bark that hang from their trunks. "Ironbarks," on the other hand, are eucalyptus trees with rough, furrowed bark similar to that of an oak or an elm tree.
The Gum in "Gum Trees"
Australians are familiar with the tendency of some eucalyptus trees to exude a sticky, gummy substance from their bark. This gum draws many insects and sap-eaters to the eucalyptus tree, creating a synergistic relationship that is beneficial to both tree and sap-eater. Aboriginals also enjoyed chewing on eucalyptus sap-gum.
Australia's kookaburra, a relative of the kingfisher with a laughing, raucous call, especially enjoys snacking on the gum from eucalyptus. In fact, a well-known Australian song beloved by young and old, depicts the relationship between kookaburra and eucalyptus: "Kookaburra sits on the old gum tree, eating all the gum drops he can see."
Lovers of Fire
Bush fires plague many of the driest areas of Australia. Much of the continent's plant life has adapted to these fire outbreaks, and eucalyptus trees are no exception. Not only have the trees adapted to bush fires, they thrive and flourish because of them. The hard, woody seed pods of many types of eucalyptus rely on the intense heat of a bush fire to force the often-bell-shaped seed pods to pop open and release the seeds trapped inside. Not only do these trees rely on bush fires for survival, some varieties contain so much plant oil within their bark and leaves, that the trees seem to encourage the spread of fires and combust quite easily. Dry strings of old bark only adds to the conflagration. The seeds eventually fall on fertile ash or soil, continuing the eucalyptus trees life cycle.
A Haven for Wildlife
The often brightly colored, fringed blooms of many varieties of eucalyptus trees attract large numbers of birds, insects and other nectar-seekers. Sugar gliders feed on the sticky sap of eucalyptus; termites hollow huge numbers of eucalyptus trees annually, destroying many trees, but, in turn, drawing insect-feeding birds and animals that leave behind nutrient-rich droppings to fertilize any living eucalyptus trees or their saplings. Many animals make their homes in hollow eucalyptus trees.
Koalas thrive on the slender, scented leaves of eucalyptus trees. They eat, sleep and live almost exclusively in eucalyptus trees.