Eucalyptus regnans, commonly known as the mountain ash, is a species of tree native to southeastern Australia. It is one of the tallest tree species in the world, often reaching heights of over 90 meters (295 feet). The tree thrives in cool, moist climates and is typically found in mountainous regions, where it plays a crucial role in the local ecosystem. The bark of Eucalyptus regnans is smooth and sheds in long strips, revealing a pale, creamy trunk. Its leaves are lance-shaped and aromatic, containing essential oils. This species is also important for timber production, as its wood is valued for its strength and durability.