Australian Blackwood
Encyclopedia
Acacia melanoxylon, commonly known as the Australian Blackwood, is an Acacia
species
native in eastern Australia
. The species is also known as Sally Wattle, Lightwood, Hickory, Mudgerabah, Tasmanian Blackwood or Black Wattle (சீமைவேல் in Tamil ). This tree species grows fast and tall, up to 45 m height. It has a wide ecological tolerance, occurring over an extensive range of soils and climatic conditions, but develops better in colder climates. Control of its invasion of natural vegetation, commercial timber plantations and farmland in several host counties incur considerable costs, but its timber value and nursing of natural forest succession provides a positive contribution.
Australian blackwood seasons easily with some possible cupping when boards are inadequately restrained. The timber produces very 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.
s were not forced by food shortages (as result of drought or other natural phenomena) to switch to this food source. Soil-stored seed banks develop that can remain viable for many years. Seeds germinate easily when placed in hot (boiling water) over night, or when soil-stored seeds are heated by the sun (in disturbed or exposed sites), or after fire (Hill, 1982). Acacia melanoxylon reproduces prolifically after fire.
Seed can be dispersed by the following methods
It can also multiply by vegetative methods, coppice shoots develop from cut and damaged stems, and from damaged roots.
s in Australia
, from the Atherton Tableland
(17°S) in Queensland
above 500 m above sea level to central Tasmania
(43°S) between sea level and 1000 m above sea level (Farell and Ashton, 1978; Jennings, 2002). In these areas, it occurs as an understorey tree in wet eucalypt
forests, as a pioneer to co-dominant trees in riverine rainforest and as a dominant tree in blackwood/tea tree
swamp
s in northwest Tasmania. It is best adapted to cooler moist sites.
It tolerates drought, poor drainage, any soil, salt air, gusty, steady or cold winds if grown in open, fog, smog
, temperature extremes, sun, or shade. Occurs in agricultural areas, coastland, disturbed areas, estuaries, natural forest, planted forests, range/grasslands, riparian zones, scrub/shrublands, urban areas, wetlands.
This fast growing perennial tree is a succession
al species. It lives for 15 – 50 years, regularly producing large numbers of well-dispersed seeds. Seed viability is sufficiently long to bridge the time between successive seedling stages.
In South-east Queensland it is an important host plant for a number of indigenous butterfly larvae, including Tailed Emperor (Polyura sempronius
); Silky Hairstreak
(Pseudalmenus chlorinda); Imperial Hairstreak (Jalmenus evagoras evagoras); Stencilled Hairstreak (Jalmenus ictinus) & Large Grass-yellow (Eurema hecabe hecabe).
and eucalypt
plantations. Tree stands facilitate the establishment of natural evergreen
forest species and the development of regrowth forest. Windfall
s obstruct water flow along invaded streams and rivers. Root suckering, it may require root barriers when planted for landscaping in built-up areas.
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. 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.
Plants in natural ecosystems should be removed before they flower and produce seed.
ns derive an analgesic
from the tree.
The wood is very good for many uses including furniture, tools, boats, and wooden kegs. It is of about the same quality as walnut and it is well-suited for shaping with steam. The bark has a tannin
content of about 20%. It may also be used for producing decorative veneers.
The tree's twigs and its bark are used to poison fish as a way of fishing.
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.
Acacia
Acacia is a genus of shrubs and trees belonging to the subfamily Mimosoideae of the family Fabaceae, first described in Africa by the Swedish botanist Carl Linnaeus in 1773. Many non-Australian species tend to be thorny, whereas the majority of Australian acacias are not...
species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
native in eastern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
. The species is also known as Sally Wattle, Lightwood, Hickory, Mudgerabah, Tasmanian Blackwood or Black Wattle (சீமைவேல் in Tamil ). This tree species grows fast and tall, up to 45 m height. It has a wide ecological tolerance, occurring over an extensive range of soils and climatic conditions, but develops better in colder climates. Control of its invasion of natural vegetation, commercial timber plantations and farmland in several host counties incur considerable costs, but its timber value and nursing of natural forest succession provides a positive contribution.
Description
Acacia melanoxylon grows as an unarmed, evergreen tree 8-15 (sometimes up to 45) m high, with a straight trunk and dense and pyramidal to cylindrical crown, sometimes with heavy spreading branches. The leaves are bipinnate (feathery) on seedlings and coppice shoots turn into phyllodes. Phyllodes are 7-10 cm long, greyish turning dark dull-green, straight to slightly curved, with 3-7 prominent longitudinal veins and fine net-veins between; often bipinnate on young plants and coppice shoots. Pale yellow, globular flower heads are followed by Reddish-brown pods, narrower than phyllodes, slightly constricted, twisted; flat roundish shiny black seeds 2-3 mm long, seeds almost encircled by pinkish-red seed stalks (aril)" (Henderson, 1995. In PIER, 2002). It has a shallow root system with dense, surface feeder roots.Timber
Acacia melanoxylon is valued for its highly decorative timber which may be used as a cabinet timber, for musical instruments or 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.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 rather variable results. The wood may be stained easily and produces a high quality finish.Australian blackwood seasons easily with some possible cupping when boards are inadequately restrained. The timber produces very 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.
Reproduction
Seed dispersal: The pink-red aril attracts birds for dispersal of the seed. Once birds in host-countries become adapted to feeding on the pink-red aril around the seed, the seed is dispersed widely, as in South Africa. It is possible that in host countries where the species has not become invasive, birds and/or other frugivoreFrugivore
A frugivore is a fruit eater. It can be any type of herbivore or omnivore where fruit is a preferred food type. Because approximately 20% of all mammalian herbivores also eat fruit, frugivory is considered to be common among mammals. Since frugivores eat a lot of fruit they are highly dependent...
s were not forced by food shortages (as result of drought or other natural phenomena) to switch to this food source. Soil-stored seed banks develop that can remain viable for many years. Seeds germinate easily when placed in hot (boiling water) over night, or when soil-stored seeds are heated by the sun (in disturbed or exposed sites), or after fire (Hill, 1982). Acacia melanoxylon reproduces prolifically after fire.
Seed can be dispersed by the following methods
- Digestion/excretion: Birds (ingest small seeds with pink-red aril), Primates (ingest seeds with pods).
- For ornamental purposes (local): Nursery trade, Landscaping, Tree seed distributors.
- Garden escape/garden waste
- Road vehicles
- Water currents: Seeds with pods, floating vegetation/debris. (Geldenhuys, pers.comm. 2003)
- Wind
It can also multiply by vegetative methods, coppice shoots develop from cut and damaged stems, and from damaged roots.
Ecology and habitat
It is native to rainforestRainforest
Rainforests are forests characterized by high rainfall, with definitions based on a minimum normal annual rainfall of 1750-2000 mm...
s in Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, from the Atherton Tableland
Atherton Tableland
The Atherton Tableland is a fertile plateau which is part of the Great Dividing Range in Queensland, Australia. It is located west to south-south-west inland from Cairns, well into the tropics, but its elevated position provides a climate suitable for dairy farming. It has an area of around...
(17°S) in Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
above 500 m above sea level to central Tasmania
Tasmania
Tasmania is an Australian island and state. It is south of the continent, separated by Bass Strait. The state includes the island of Tasmania—the 26th largest island in the world—and the surrounding islands. The state has a population of 507,626 , of whom almost half reside in the greater Hobart...
(43°S) between sea level and 1000 m above sea level (Farell and Ashton, 1978; Jennings, 2002). In these areas, it occurs as an understorey tree in wet eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
forests, as a pioneer to co-dominant trees in riverine rainforest and as a dominant tree in blackwood/tea tree
Tea tree
Tea tree or Ti-tree is a popular name that has been applied to a number of different, unrelated plants:*Camellia sinensis , from which black, green, oolong and white tea are all obtained....
swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
s in northwest Tasmania. It is best adapted to cooler moist sites.
It tolerates drought, poor drainage, any soil, salt air, gusty, steady or cold winds if grown in open, fog, smog
Smog
Smog is a type of air pollution; the word "smog" is a portmanteau of smoke and fog. Modern smog is a type of air pollution derived from vehicular emission from internal combustion engines and industrial fumes that react in the atmosphere with sunlight to form secondary pollutants that also combine...
, temperature extremes, sun, or shade. Occurs in agricultural areas, coastland, disturbed areas, estuaries, natural forest, planted forests, range/grasslands, riparian zones, scrub/shrublands, urban areas, wetlands.
This fast growing perennial tree is a succession
Ecological succession
Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...
al species. It lives for 15 – 50 years, regularly producing large numbers of well-dispersed seeds. Seed viability is sufficiently long to bridge the time between successive seedling stages.
In South-east Queensland it is an important host plant for a number of indigenous butterfly larvae, including Tailed Emperor (Polyura sempronius
Polyura sempronius
The Tailed Emperor butterfly lives on the east coast of Australia....
); Silky Hairstreak
Silky Hairstreak
The Silky Hairstreak also known as the Chlorinda Hairstreak is a butterfly belonging to the family Lycaenidae. It occurs in Australia.-Taxonomy:...
(Pseudalmenus chlorinda); Imperial Hairstreak (Jalmenus evagoras evagoras); Stencilled Hairstreak (Jalmenus ictinus) & Large Grass-yellow (Eurema hecabe hecabe).
Invasive species
Replaces native non-tree vegetation, such as grassland and shrubland, and transforms such habitats. It invades the understorey of relatively open pinePine
Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...
and eucalypt
Eucalypt
Eucalypts are woody plants belonging to three closely related genera:Eucalyptus, Corymbia and Angophora.In 1995 new evidence, largely genetic, indicated that some prominent Eucalyptus species were actually more closely related to Angophora than to the other eucalypts; they were split off into the...
plantations. Tree stands facilitate the establishment of natural evergreen
Evergreen
In botany, an evergreen plant is a plant that has leaves in all seasons. This contrasts with deciduous plants, which completely lose their foliage during the winter or dry season.There are many different kinds of evergreen plants, both trees and shrubs...
forest species and the development of regrowth forest. Windfall
Windfall
Windfall is a serial drama television series about a group of people in an unnamed small city who win almost $400 000 000 in a lottery. The series premiered Thursday, June 8, 2006 on NBC, taking the time slot occupied by ER during the rest of the year.On August 31, 2006, NBC announced the show's...
s obstruct water flow along invaded streams and rivers. Root suckering, it may require root barriers when planted for landscaping in built-up areas.
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. 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.
Management
Preventative measures: In general, blackwood is either recognised as an invader species in some areas, or it does not invade in other areas (although its potential to invade is recognised), or its invasion status is not yet recognised. South Africa provides information on the management of areas where blackwood invasion has become a problem. In areas where blackwood is not yet an invasion problem or where the species is in an early stage of invasion, the following options could be followed:- Be careful with the introduction of Acacia melanoxylon into natural areas or area where the species is not present because of the potential of the species to become invasive.
- Production of viable seed should be monitored.
- Seedling recruitment should be monitored in natural ecosystemEcosystemAn ecosystem is a biological environment consisting of all the organisms living in a particular area, as well as all the nonliving , physical components of the environment with which the organisms interact, such as air, soil, water and sunlight....
s and along drainage lines.
Plants in natural ecosystems should be removed before they flower and produce seed.
Uses
Indigenous AustraliaAustralia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
ns derive an analgesic
Analgesic
An analgesic is any member of the group of drugs used to relieve pain . The word analgesic derives from Greek an- and algos ....
from the tree.
The wood is very good for many uses including furniture, tools, boats, and wooden kegs. It is of about the same quality as walnut and it is well-suited for shaping with steam. The bark has a tannin
Tannin
A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...
content of about 20%. It may also be used for producing decorative veneers.
The tree's twigs and its bark are used to poison fish as a way of fishing.
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.
General references
Public Domain Information From:- The IUCN/SSC Invasive Species Specialist Group (ISSG) (http://www.issg.org), Global Invasive Species Database: http://www.issg.org/database/welcome/,
- Related Disclaimer: http://www.issg.org/database/welcome/disclaimer.asp
- Cal-IPC Plant Assessment Form (http://portal.cal-ipc.org/files/PAFs/Acacia%20melanoxylon.pdf)
External links
- Acacia melanoxylon
- http://www.ellisguitars.com/AustralianBlackwood.html Musical instrument maker utilizing Acacia melanoxylon
- http://www.fidockdrums.com/product.htm#blackwood
- Management of Blackwood in Plantations http://www.mtg.unimelb.edu.au/publications/Blackwood%20conference%20paper.pdf