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Mountain Ash Fact Sheet

Mountain Ash

Common Name: Mountain Ash

Order: Myrtales

Family: Myrtaceae

Genus: Eucalyptus

Species: E. regnans

Size and Growth Rate: Mountain ash grows relatively quickly, with an average annual growth rate of 3 feet (1 meter). They are the tallest of the eucalypts, capable of reaching heights of up to 490 feet (150 meters) but generally grow to about 330 feet (100 meters). It’s the world’s tallest flowering plant.

Life Span: Mountain ash has an average lifespan of 400 years.

Reproduction: The primary form of reproduction occurs through dispersal of seeds. This process is often initiated during severe fires when intense heat releases seeds from their hard casings, called gumnuts. The seeds germinate on the forest floor, receiving a boost of nutrients from the ashes left behind from the fires, and flourishing in the sunlight which reaches the ground through now-bare tree branches. Mountain ash trees can also regenerate through shoots sprouting from dormant buds protected beneath the fire-insulated bark., or which are stimulated when trees suffer significant loss of top growth—though this form of regeneration happens far less frequently.

Appearance: The base of the tree is quite rough but, as the tree grows, this rough bark sheds large ribbons, leaving the highest part of the tree with a smoother exterior. The lowest branches are nearly 100 feet from its base. The mountain ash leaf varies in shape; clusters of white flowers blossom during Australia’s summer and autumn months, January to March.

Habitat: The mountain ash grows in deep soil in the cool, mostly mountainous areas of Victoria and Tasmania on the Australian continent. These regions are located at an approximate altitude of 3,300 feet (1,000 meters) with an average annual rainfall of 47 inches (1200 millimeters).

Conservation Status: The species is not considered to be at risk of extinction.

Additional Facts:

  • Mountain ash is a common name given to other unrelated species of trees, such as the Fraxinus texensis in Texas, the Sorbus in North America, and the Sorbus aucuparia, found mostly in Ireland and Britain.
  • In addition to mountain ash, the species has also been referred to as Victorian ash, swamp gum, Tasmanian oak and stringy gum.
  • The Australian mountain ash is the tallest flowering plant, and the tallest of the eucalypts.
  • Only California coastal redwoods are taller, though their heights are comparable.
  • The species is an evergreen, maintaining its leaves year-round.
  • Mountain ash is part of a diverse group of plants known as Angiosperms, or flowering plants, classified for their seed, flower, and fruit production.
  • Its leaves produce volatile, highly combustible oils.
  • Mountain ash produces excellent hardwood timber prized by the lumber industry for building and paper products, and also provides essential habitat for a wide variety of birds and mammals, including the endangered Leadbeater’s possum.


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