A vast genus of fast-growing Australian evergreen trees with peeling bark and aromatic oily leaves, now the most widely planted hardwood worldwide.
Where it grows
The Tasmanian blue gum is one of more than 800 Eucalyptus species, almost all native to Australia. Blue gums and other industrial eucalypts have been planted across the tropics and subtropics — from Portuguese hillsides to Brazilian pulp plantations and Ethiopian highland farms — for their extraordinarily fast growth and adaptable wood.
How to recognise it
Gum trees show distinctive bark shedding: long ribbons or polygonal patches peel away to reveal smooth pale wood beneath. The juvenile leaves are typically rounded and silvery-blue, while the adult leaves are lance-shaped, leathery, and hang vertically. Crushing them releases the famous menthol-camphor scent of eucalyptus oil.
Uses
Eucalypts dominate global short-rotation hardwood plantations for pulp, paper, and rayon. Their dense, hard heartwood (sometimes called Tasmanian oak in trade) is used for flooring and decking. Steam-distilled leaf oil — rich in cineole — is a cough medicine, insect repellent, and aromatherapy staple.
Ecology
Eucalypts coevolved with fire: their oils encourage hot crown fires that kill competitors while their lignotubers re-sprout. In introduced ranges they can fuel catastrophic wildfires and dry up watersheds — making eucalyptus a contentious tree in California, Portugal, and South Africa.