Eucalyptus in Australia: Ecology, Fire, and Wildlife

Overview

Eucalyptus dominates Australia's forests with over 700 species, known variously as gum, mallee, box, ash, ironbark, and stringybark. These trees are ecological keystones: they feed koalas, withstand extreme drought and fire, and possess valuable medicinal properties.

Deep History

Among the world's tallest trees, eucalypts have existed in Australia for millions of years. Their tolerance for poor soils, drought, and flame allowed them to colonize the continent and remain its dominant vegetation.

Fire Survival Strategies

Eucalypts not only survive frequent bushfires—they often require them. Thick bark insulates the cambium, while heat triggers seed release from woody capsules. Some species even produce flammable oils that encourage fire spread, clearing competition. Post-fire, a chemical shift in the tree stimulates epicormic regrowth, and wind-dispersed seeds germinate on the ash bed.

Termites: Architects of Habitat

After fire, termites hollow out weakened trunks and branches, creating nest cavities for kookaburras, cockatoos, rosellas, and sugar gliders.

Koala Diet and Distribution

Koalas inhabit Queensland, New South Wales, Victoria, and South Australia, feeding on leaves of about 20 eucalypt species. Their diet varies regionally based on local species composition. Nocturnal feeders, they consume leaves and young shoots almost exclusively.