Acacia melanoxylon

Acacia melanoxylon, commonly known as the Australian blackwood, is an Acacia species native in South eastern Australia. The species is also known as Blackwood, hickory, mudgerabah, Tasmanian blackwood, or blackwood acacia.

Acacia melanoxylon R. Br. ex Ait. f. foliage and seeds with elaiosomes
Acacia melanoxylon R. Br. ex Ait. f. seeds

Australian blackwood
Flowering twigs of Acacia melanoxylon
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Rosids
Order: Fabales
Family: Fabaceae
Clade: Mimosoideae
Genus: Acacia
Species:
A. melanoxylon
Binomial name
Acacia melanoxylon
Range of Acacia melanoxylon
Synonyms[1]
  • Acacia arcuata Spreng.
  • Acacia melanoxylon R.Br. var. arcuata (Spreng.) Ser.
  • Acacia melanoxylon R.Br. var. obtusifolia Ser.
  • Acacia melanoxylum R.Br.
  • Mimosa melanoxylon (R.Br.) Poir.
  • Racosperma melanoxylon (R.Br.) C.Mart.
  • Racosperma melanoxylon (R.Br.) Pedley

Timber

Acacia melanoxylon is valued for its decorative timber which may be used in cabinets, musical instruments and in boatbuilding.

Appearance

Sapwood may range in colour from straw to grey-white with clear demarcation from the heartwood. The heartwood is golden to dark brown with chocolate growth rings. The timber is generally straight grained but may be wavy or interlocked. Quartersawn surfaces may produce an attractive fiddleback figure. The wood is lustrous and possesses a fine to medium texture.[2]

The name of the wood may refer to dark stains on the hands of woodworkers, caused by the high levels of tannin in the timber.

Properties

Acacia melanoxylon timber has a density of approximately 660 kg/m3 and is strong in compression, resistant to impact and is moderately stiff. It is moderately blunting to work with tools and bends well. It may be nailed or screwed with ease, but gluing may produce variable results. The wood is easily stained and produces a high-quality finish.

Australian blackwood seasons easily with some possible cupping when boards are inadequately restrained. The timber produces little movement once seasoned.

The timber may be attacked by furniture beetles, termites and powder-post beetles (sapwood). It is resistant to effective preservative treatments.

Acacia melanoxylon older bark

Invasive species

It has been introduced to many countries for forestry plantings and as an ornamental tree. It now is present in Africa, Asia, Europe, Indian Ocean, the Pacific Ocean, South America and the United States. It is a declared noxious weed species in South Africa and is a pest in Portugal's Azores Islands. It was also recently listed by the California Invasive Plant Council (Cal-IPC) as an invasive weed that may cause limited impact (Knapp 2003). Its use as a street tree is being phased out in some locales because of the damage it often causes to pavements and underground plumbing. In some regions of Tasmania, blackwood is now considered a pest.

Uses

Indigenous Australians derive an analgesic from the tree.[3] It was also used to make spearthrowers and shields.[4]

The wood has many uses including wood panels, furniture, fine cabinetry, tools, boats, inlayed boxes and wooden kegs. It is approximately the same quality as walnut, and is well-suited for shaping with steam. The bark has a tannin content of about 20%.[5] It may also be used for producing decorative veneers.

The tree's twigs and bark are used to poison fish as a way of fishing.[6] This tree can also be used as a fire barrier plant, amongst other plants, in rural situations

Plain and figured Australian blackwood is used in musical instrument making (in particular guitars, drums, Hawaiian ukuleles, violin bows and organ pipes), and in recent years has become increasingly valued as a substitute for koa wood.

References

Notes
  1. ILDIS LegumeWeb
  2. Porter, Terry (2006). Wood: Identification and Use. East Sussex, GB: Guild of Master Craftsman Publications Ltd. p. 37.
  3. Analgesic Plants Archived April 23, 2007, at the Wayback Machine Australian New Crops Newsletter
  4. "Aboriginal Plant use and Technology" (PDF). Australian National Botanic Garden. Retrieved 11 November 2016.
  5. Google Books Select Extra-tropical Plants Readily Eligible for Industrial Culture Or Naturalization By Ferdinand von Mueller
  6. "A. Melanoxylon". Archived from the original on 2007-05-27. Retrieved 2007-06-19.

General references
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