Common Name: African Blackwood

General Information

Dalbergia melanoxylon is a small, spiny, heavily branched deciduous tree, typically 4.5 - 7.5 metres tall but occasionally reaching 15 metres[].
The tree is harvested from the wild as a local source of medicines and materials. The wood is one of the most valuable produced in Africa with a wide range of uses[]. It is particularly valued in the wood carving industry and in musical instrument manufacture[]. It is one of 33 species named as being a suitable Hongmu (red wood) timber, used for producing high quality Chinese furniture following traditions from the Ming and Quing dynasty, which makes it a particularly valuable wood[]. The wood is traded internationally in small volumes, but at very high prices[]. The plant is also grown to re-establish woodland and to provide shelter.
Levels of exploitation are very high and larger or suitably exploitable individuals are becoming increasingly scarce[]. There is cause for concern over genetic erosion in many populations[]. The plant is classified as 'Near Threatened' in the IUCN Red List of Threatened Species(2011)[].

Known Hazards

None known

Botanical References

Range

Africa - drier areas from Senegal to Ethiopia, south to S. Africa.

Habitat

Grows under a wide range of conditions including semi-arid, subhumid and tropical lowland areas[]. It is often found on dry, rocky sites but is most frequent in the mixed deciduous forests and savannahs of the coastal region[].

Properties

Weed Potential	Yes
Conservation Status	Near Threatened
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	6.00 m
Growth Rate	Slow
Pollinators	Bees
Self-fertile	No
Cultivation Status	Cultivated, Wild

Cultivation Details

A plant of low to moderate elevations in the tropics, being found at elevations from sea level to 1,200 metres[]. It grows in areas where the mean annual temperature is in the range 18 - 35°c and the mean annual rainfall is 700 - 1,200 mm[].
Succeeds in a variety of soils, from loamy sands to clayey Vertisols (black cotton soils)[]. This species demands water and light and therefore is common near water and will not regenerate under heavy cover[].
When introduced into India and Australia, the plant became naturalized[]. In western Australia it behaved as a very aggressive weed and was quickly eradicated[].
The species is extremely slow growing. Seven year old trees are only up to 4 metres tall and it takes 70 - 100 years for trees to attain timber size[, ].
Trees coppice successfully and also produce root suckers[].
Trees generally exhibit heavy annual seed production[].
Mature trees are fire tolerant[].
This species has a symbiotic relationship with certain soil bacteria, these bacteria form nodules on the roots and fix atmospheric nitrogen. Some of this nitrogen is utilized by the growing plant but some can also be used by other plants growing nearby[].

Edible Uses

None known

Medicinal

The roots are said to be anthelmintic and aphrodisiac[]. A decoction is used to prevent miscarriage, to treat abdominal pain, diarrhoea, gonorrhoea and syphilis[].

The wood smoke is inhaled to treat headaches, colds and bronchitis[, ].

The stem and root bark is used in traditional medicine to treat diarrhoea in combination with baobab or tamarind fruits[].
A bark decoction or bark powder is used to clean wounds[].

A leaf decoction is used to relieve pain in the joints[].
The leaf sap is taken to treat inflammations in mouth and throat[].

Bark extracts have shown antibacterial and antifungal activities, thus supporting the traditional application for cleansing wounds[].

Agroforestry Uses:

The tree provides good mulch and may improve the soil by nitrogen fixation[]. It can be used to avoid soil erosion because of its extensive root system. It is also useful in windbreaks and live fences[].

Other Uses

The heartwood is purplish black, sometimes darker towards the outside, with light streaks and not always uniform in colour; it is sharply differentiated from the up to 12cm wide band of white or yellowish-white sapwood[]. The timber is slightly oily, exceptionally hard and very heavy, brittle and somewhat fissile[]. The heartwood is extremely durable and resistant to all forms of biological deterioration[]. The sapwood, however, is susceptible to fungal or insect attack[]. The dry wood is difficult to saw or plane; it blunts saws and cutters and cannot be nailed or screwed without drilling; it is, however, among the finest of all turnery timbers, cutting exactly and finishing to a brilliantly polished, lustrous surface, dry and cold to the touch[]. Other products made from the timber include carvings, turnery and marquetry to produce sculptures, musical instruments, ornaments, inlays, chess pieces, walking sticks, bearings and many other products[]. The main industrial use, long supporting an export trade from East Africa and Mozambique, is the manufacture of musical instruments, especially woodwinds. With its high density and fine texture, the wood produces a beautiful musical tone[]. It is stable, stands up to metalwork processes, and takes an excellent finish[].
The wood is used as a fuel and to make charcoal[]. Its calorific value is more than 49,000 kcal/kg. Heat generation is so high that fires of D. Melanoxylon have been reported to melt cooking utensils[].

Propagation

Seed extracted from pods germinate readily without pre-treatment[]. They should be kept in the shade for 2 weeks after sowing, but can then be placed in full sun[]. They germinate 8 - 20 days after sowing, with a germination rate of 50 - 60%[]. Although pre-treatment of seeds is not necessary, soaking the seeds in water accelerates germination[]. Experimental work in Tanzania suggests that survival and growth are improved by planting 2-year-old stumps that are 14 cm long, comprising 12 cm of root and 2 cm of shoot[]. These should be planted in the early or middle part of the rainy season, followed by intensive weeding. Potted seedlings may also be used, but they tend to grow more slowly. When seedlings are raised in pots, frequent root pruning is mandatory[]. Delayed pruning leads to seedling shock[].
Like many species within the family Fabaceae, once they have been dried for storage the seeds of this species may benefit from scarification before sowing in order to speed up germination. This can usually be done by pouring a small amount of nearly boiling water on the seeds (being careful not to cook them!) and then soaking them for 12 - 24 hours in warm water. By this time they should have imbibed moisture and swollen - if they have not, then carefully make a nick in the seedcoat (being careful not to damage the embryo) and soak for a further 12 hours before sowing[].
Seed storage behaviour is orthodox; viability can be maintained for several years in hermetic storage at 3°c with 9 - 12% mc[].
Softwood cuttings of many species, especially if taken from younger plants, will root in a well-drained, sandy medium in a closed case with bottom heat[].

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