Common Name(s): Australian blackwood, Tasmanian blackwood, Acacia blackwood
Scientific Name: Acacia melanoxylon
Distribution: Native to Tasmania and eastern Australia; also introduced to Africa, South America, and southern Asia
Tree Size: 65-100 ft (20-30 m) tall,
2-3 ft (.6-1 m) trunk diameter
Average Dried Weight: 40.0 lbs/ft3 (640 kg/m3)
Specific Gravity (Basic, 12% MC): 0.54, 0.64
Janka Hardness: 1,160 lbf (5,180 N)
Modulus of Rupture: 15,020 lbf/in2 (103.6 MPa)
Elastic Modulus: 2,148,000 lbf/in2 (14.82 GPa)
Crushing Strength: 7,770 lbf/in2 (53.6 MPa)
Shrinkage: Radial: 3.9%, Tangential: 7.9%,
Volumetric: 11.9%, T/R Ratio: 2.0
Color/Appearance: Color can be highly variable, but tends to be medium golden or reddish brown, similar to koa or mahogany. There are usually contrasting bands of color in the growth rings, and it is not uncommon to see boards with ribbon-like streaks of color. Boards figured with wavy and/or curly grain are also not uncommon.
Grain/Texture: Grain is usually straight to slightly interlocked, and sometimes wavy. Uniform fine to medium texture.
Rot Resistance: Rated as moderately durable regarding decay resistance, though susceptible to insect attack.
Workability: Australian blackwood is easily worked with both hand and machine tools, though figured wood and pieces with interlocked grain can cause tearout. Australian blackwood turns, glues, stains, and finishes well, though two-part catalyzed finishes can sometimes be slowed in their curing. Responds well to steam bending. Reported to have good impact resistance.
Odor: No characteristic odor.
Allergies/Toxicity: Although severe reactions are quite uncommon, Australian blackwood has been reported as a sensitizer. Usually most common reactions simply include eye, skin, and respiratory irritation, as well as asthma-like symptoms. See the articles Wood Allergies and Toxicity and Wood Dust Safety for more information.
Pricing/Availability: Although Australian blackwood is considered an invasive species and a pest in some areas, the lumber is still fairly expensive, and figured wood can be very expensive. Nonetheless, it has been used as a lower-cost alternative to the even costlier Hawaiian koa (Acacia koa).
Sustainability: This wood species is not listed in the CITES Appendices or on the IUCN Red List of Threatened Species. Moreover, it is considered an invasive species in some areas (see notes and references below).
Common Uses: Veneer, furniture, cabinetry, musical instruments, gunstocks, turned objects, and other specialty wood objects.
Comments: Although called ‘blackwood,’ the name is somewhat of a misnomer, as its wood is not really black. Rather, its lustrous golden brown grain has been used as a sustainable alternative to the closely related koa (Acacia koa). The species has been introduced to a number of regions worldwide—either as an ornamental shade tree, or on a plantation for lumber—and in many areas, the hardy trees have become an invasive species.Souza-Alonso, P., Rodríguez, J., González, L., & Lorenzo, P. (2017). Here to stay. Recent advances and perspectives about Acacia invasion in Mediterranean areas. Annals of Forest … Continue readingHussain, M. I., González, L., Souto, C., & Reigosa, M. J. (2011). Ecophysiological responses of three native herbs to phytotoxic potential of invasive Acacia melanoxylon R. Br. Agroforestry … Continue reading
Australian blackwood is very closely related to koa, a species endemic to the island of Hawaii. Acacia melanoxylon is believed to be the ancestral source of both A. koa, and also highland tamarind (Acacia heterophylla)—another island species—endemic to Reunion island.Le Roux, J. J., Strasberg, D., Rouget, M., Morden, C. W., Koordom, M., & Richardson, D. M. (2014). Relatedness defies biogeography: the tale of two island endemics (Acacia heterophylla and A. … Continue reading On a practical level, the wood of Australian blackwood tends to have a straighter grain, and slightly better machining characteristics when compared to koa. However, while pieces of koa with dramatic coloration and figured or wild grain tend to be more commonplace, on the whole, the two species are virtually indistinguishable. (See notes on identification below.)
Porosity: diffuse porous
Arrangement: solitary and radial multiples
Vessels: large, few to very few
Rays: narrow width, normal spacing; can be reddish color that blends in with surrounding wood fibers
Lookalikes/Substitutes: Hawaiian koa (Acacia koa) is anatomically indistinguishable from Australian blackwood, at least on a macroscopic level. (When viewed under microscope, about 50% of the rays in koa are uniseriate, while Australian blackwood’s rays are only about 20% uniseriate.)
Notes: Heartwood fluoresces under blacklight.
|↑1||Souza-Alonso, P., Rodríguez, J., González, L., & Lorenzo, P. (2017). Here to stay. Recent advances and perspectives about Acacia invasion in Mediterranean areas. Annals of Forest Science, 74(3), 1-20.|
|↑2||Hussain, M. I., González, L., Souto, C., & Reigosa, M. J. (2011). Ecophysiological responses of three native herbs to phytotoxic potential of invasive Acacia melanoxylon R. Br. Agroforestry systems, 83(2), 149-166.|
|↑3||Le Roux, J. J., Strasberg, D., Rouget, M., Morden, C. W., Koordom, M., & Richardson, D. M. (2014). Relatedness defies biogeography: the tale of two island endemics (Acacia heterophylla and A. koa). New Phytologist, 204(1), 230-242.|