Eucalyptus trees are native to Australia, where over 750 species grow across nearly every corner of the continent. A small number of species also occur naturally in parts of New Guinea and nearby Indonesian islands, but Australia is overwhelmingly where the genus evolved, diversified, and still dominates the landscape today.
Native Range Across Australia
Eucalyptus species cover all Australian states and territories, filling every environment except the driest deserts and the interior of tropical rainforests. The most widespread species, river red gum, grows in every mainland state, typically along waterways. In the southeast, the forests hold commercially important species like mountain ash, messmate stringybark, and blackbutt. Southwestern Australia is dominated by jarrah and karri. In the tropical north, Darwin woollybutt and Darwin stringybark are the characteristic species.
In the arid interior, eucalyptus trees survive only along river edges, where their roots can reach water. Across the drier inland regions of southern Australia, many species grow as “mallees,” a shrubby, multi-stemmed form rather than a tall single-trunk tree. This variety of growth forms helps explain how one genus managed to occupy such wildly different climates, from alpine highlands to semi-desert.
An Ancient Gondwanan Origin
Eucalyptus is far older than most people realize. Molecular estimates suggest the group has been around for roughly 65 million years, dating back to a time when Australia, South America, and Antarctica were still connected as part of the supercontinent Gondwana. The oldest known macrofossils of eucalyptus, about 52 million years old, were found not in Australia but in Patagonia at the southern tip of South America. Fossil pollen of similar age has turned up in southeastern Australia and eastern Antarctica.
These fossils tell a story of a genus that once stretched across connected southern landmasses. As Gondwana broke apart and the continents drifted, eucalyptus disappeared from South America and Antarctica but thrived in Australia, likely because the continent’s increasing dryness and fire-prone conditions suited the trees perfectly.
Why Fire Made Eucalyptus Dominant
Australia’s landscape burns frequently, and eucalyptus trees are built for it. Most species can resprout from the trunk and base after even high-intensity fires, thanks to buds embedded beneath the bark in specialized structures called epicormic strands. While other tree groups die back after severe burns, eucalyptus recovers quickly, sending out new green shoots within weeks. This gave eucalyptus a massive competitive advantage over millions of years, allowing it to dominate the Australian bush while fire-sensitive species retreated to protected rainforest pockets.
Eucalyptus, Corymbia, and Angophora
When people say “eucalypt,” they’re actually referring to three closely related genera in the myrtle family: Eucalyptus (758 species), Corymbia (93 species), and Angophora (10 species). The name Eucalyptus comes from Greek words meaning “well covered,” a reference to the small cap that covers each flower bud before it opens. Corymbia shares this cap, but Angophora species lack it entirely. You can also tell Angophora apart because its leaves grow in opposite pairs, while Eucalyptus and Corymbia leaves alternate along the stem.
How Eucalyptus Spread Around the World
Eucalyptus stayed confined to Australia and its nearest neighbors until Europeans began moving seeds across oceans in the late 1700s. The genus was probably first planted in Europe between 1771 and 1774, in London and at Kew Gardens. By 1794, trees were growing outdoors at the Royal Palace of Caserta near Naples. Early European plantings were ornamental or medicinal, but by the mid-1800s, countries across southwestern Europe, particularly Spain, Portugal, France, and Italy, began planting eucalyptus commercially for mine timber and railway sleepers. Later, the trees became a major source of cellulose fiber for paper and textiles.
In California, the story began in 1853, when clipper ship captain Robert Waterman planted blue gum seeds in the Suisun Valley. At first the trees were purely ornamental. But California was rapidly stripping its native forests for fuel and building material, and people grew anxious about future timber supplies. After 1870, eucalyptus became a favorite solution: it grew fast, its oil was believed to have medicinal value, and many people thought the trees were fireproof (they are not). Newspapers promoted eucalyptus enthusiastically, and the boom reached its peak when the Central and Southern Pacific Railroads announced in 1877 that they would plant eucalyptus along their entire lines for timber, climate modification, and the supposed ability to absorb “malarial poisons” from the air.
That malaria claim came from research in France and Mediterranean countries suggesting that blue gum could purify the air and prevent the disease. The real mechanism, where it existed at all, was simpler: eucalyptus plantations helped drain swampy ground where mosquitoes bred. But the mythology ran far ahead of the science, and it fueled planting campaigns worldwide.
Eucalyptus Plantations Today
Eucalyptus is now the most widely planted broadleaf tree species on Earth. As of the most recent global surveys, plantations cover more than 22.5 million hectares across at least 95 countries. Brazil is the largest grower outside Australia, using vast eucalyptus plantations for pulp and paper. China has expanded its eucalyptus acreage faster than any other country since the mid-1990s. India, South Africa, Portugal, and Spain also maintain enormous commercial plantations.
The speed of eucalyptus growth is a major reason for its global popularity. Some species can add several meters of height per year in favorable conditions, producing harvestable timber in under a decade. That same fast growth, combined with the trees’ heavy water use and tendency to outcompete native vegetation, has made eucalyptus plantations controversial in many regions. In parts of Portugal and Spain, eucalyptus monocultures have been linked to increased wildfire risk and reduced biodiversity, turning the trees from a celebrated import into an ecological concern.