Common Name(s): Australian ash, soap tree
Distribution: Southeast Asia, Pacific Islands, and Australia
Genus Size: About 20 species
Mechanical Characteristics: Wood density for most species is generally moderate for a tropical hardwood. Possesses good strength-to-weight characteristics. Grain is usually straight, with good workability.
Visual Characteristics: Heartwood of most species ranges from a pink or orange, darkening to a deeper reddish brown, sometimes with darker streaks intermixed. Contrasting sapwood is a lighter yellow color.
Identification: Australian species such as Alphitonia excelsa have pores occurring primarily as radial multiples of two to five. This, along with the unique heartwood color, is usually enough to separate it from other native species.
Comments: Despite its common name, Australian ash species are not botanically related to true ashes in the Fraxinus genus. They’re actually more closely related to buckthorn (Rhamnus cathartica), and both are contained in the broader Rhamnaceae (buckthorn) family.
Some Alphitonia species are cultivated on plantations and are considered ornamental trees. One traditional use for some species was to crush the leaves (which contain a soap-like chemical called saponins) in water, giving rise to the common name of soap tree.
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