It prefers sites with a wide range of rainfall, typically receiving 600 - 925 mm, and can thrive at various altitudes, from near sea-level to 200 m. Its native range includes areas of southeastern Australia.
Black wattle
Acacia mearnii, also known as black wattle, is a fast-growing tree native to southeastern Australia. It can reach a height of 6 to 10 meters and is adapted to a wide range of sites. Black wattle is known for its nitrogen-fixing capabilities, high-quality tannin production from the bark, and its versatile use as timber for construction, paper pulp, and fuel.
Acacia mearnii
Australia
Habitat and Distribution Acacia mearnii, commonly known as black wattle, is native to south-eastern Australia. It thrives in a wide range of sites, including areas receiving 600 - 925 mm of rainfall and altitudes from near sea-level to 200 m. It occurs in the understorey of tall, open forests dominated by eucalypts. The tree can also form dense thickets when it recolonizes cleared land. In addition to Australia, black wattle is cultivated in India, South Africa, eastern Africa, and South America. Nutritional and Industrial Uses The leaves of Acacia mearnii have a high protein content of 15%. While they are unpalatable to sheep when fed alone, they have been used as feed for cattle during drought periods in Hawaii. The tree is an efficient nitrogen fixer, making it valuable for regenerating impoverished soils. In Indonesia, black wattle is extensively used, with yields of 21 - 28 t/ha/yr of wet leaves containing 240 - 285 kg of nitrogen. Farmers in Indonesia claim that vegetables and tobacco grown in rotation with A. mearnsii yield twice as much due to the green manure provided by the trees. The bark of black wattle yields high-quality tannin (36 - 44%). The powdered bark extract is used in the production of tannin formaldehyde adhesives for exterior-grade plywood, particle board, and timber. The wood of Acacia mearnii is hard and moderately easy to work with. It is used for various purposes such as house poles, mine timbers, tool handles, cabinet making, joinery, flooring, construction timber, matchwood, and hardboard. It is also utilized for rayon pulp and paper pulp, although chipping the hard wood can be expensive. Furthermore, it is an excellent fuel wood and charcoal. International Cultivation and Recognition Black wattle is cultivated in various countries, including India, South Africa, eastern Africa, and South America. Notably, South African plantations cover an extensive area of 160,000 hectares, while Brazil has over 125,000 hectares dedicated to black wattle cultivation. Interestingly, Acacia mearnii is widely used overseas but often overlooked in its native Australia.
- Well adapted to a wide range of sites - Thrives in soils with 600 - 925 mm rainfall - Can tolerate altitudes from near sea-level to 200 m - Native to south-eastern Australia
A fast growing, nitrogen fixing tree to 6 - 10 m. It is adapted to a wide range of sites receiving 600 - 925 mm rainfall and at altitudes from near sea - level to 200 m. Native to south - eastern Australia.
Black wattle occurs in the understorey of tall, open forest dominated by eucalypts. It can form dense thickets where it has recolonised cleared land. Its native companions include Eucalyptus saligna, Eucalyptus bosistoana, Eucalyptus muellerana, Eucalyptus ovata, Eucalyptus globulus, Eucalyptus viminalis, Eucalyptus cypellocarpa, Eucalyptus radiata and Eucalyptus smithii.
The leaves have a high protein content (15%) but palatability trials with sheep showed milled leaves to be unpalatable on their own. It has been fed to cattle in Hawaii in drought periods. It is an efficient nitrogen fixer and is an ideal tree for regenerating impoverished soils. In Indone-sia where the tree is used extensively, it is found to yield 21 - 28 t/ha/yr of wet leaves, contain-ing 240 - 285 kg of nitrogen. Indonesian farmers claim that vegetables and tobacco grown in rotation with A. mearnsii give twice the yield because of the green manure the trees provide.
It yields high quality tannin (36 - 44% ) from the bark; the powdered bark extract is used to prepare tannin formaldehyde adhesives for exterior grade plywood, particle board and timber.
The wood is hard, but is moderately easy to work, and takes a good polish. The wood is used for house poles, mine timbers, tool handles, cabinet making, joinery, flooring, construction timber, matchwood and hardboard. It is used for rayon pulp arid paper pulp, although the hard wood makes chipping expensive. It has good strength characteristics for wrapping paper, and is an excellent fuel wood and charcoal.
It is cultivated in India, South Africa, eastern Africa and South America. South African plantations cover 160,000 hectares, and there are over 125,000 hectares in Brazil. This acacia is probably the best example of an Australian tree which is used extensively overseas but almost ignored in its homeland.