Why Are Eucalyptus Trees Native to Australia?

Eucalyptus trees are found in Australia because they evolved there over tens of millions of years. The genus Eucalyptus is overwhelmingly endemic to the continent, with over 95% of its 700+ species occurring naturally nowhere else. Fossil evidence suggests their ancestors have been part of the Australian landscape for at least 50 million years.

During this deep time, eucalypts developed a remarkable suite of adaptations to the continent's challenging climate—characterized by nutrient-poor soils, irregular rainfall, intense heat, and frequent wildfires. Their deep root systems tap into groundwater; their leathery, pendant leaves minimize water loss; and their lignotubers (swollen woody bases) allow rapid regrowth after fire. Additionally, they produce potent essential oils and tannins that deter herbivores and suppress competing plants.

These evolutionary innovations have made eucalypts the dominant trees across vast swathes of Australia, defining the ecology of the bush and providing critical habitat for iconic wildlife like koalas.