Common Name: Benin Mahogany

General Information

Khaya grandifoliola is a medium to large-sized tree that can grow up to 40 metres tall[]. It is usually deciduous in the dry season; the young leaves are strikingly reddish and often occur together with flowers[]. The bole, which can have buttresses up to 3 metres tall, is up to 120cm in diameter and can be branchless for up to 23 metres[]. It is often twisted or leaning near the top[].
The tree is heavily exploited in the wild for its valuable timber, which is traded internationally. It is occasionally grown in plantations within its natural area of distribution, e.g. in Côte d’Ivoire and Ghana, and trial plantations have been established in Indonesia[]. The tree is also planted as a roadside tree and ornamental shade tree[].
Exploitation is heavy: extraction of mature individuals from subpopulations has been comprehensive. Regeneration is poor away from parent individuals and is best at the savannah-forest boundary. The tree is classified as 'Vulnerable' in the IUCN Red List of Threatened Species(2010)[]

Known Hazards

The bark is used as a fish poison[].

Botanical References

Range

Western tropical Africa - Guinea-Bissau to Sudan, south to the Congo.

Habitat

Occurs in semi-deciduous forest, especially in drier types and in savannah, but in the latter case usually along watercourses[]. It can sometimes be found in rocky and hilly parts of moist semi-deciduous forest[].

Properties

Conservation Status	Vulnerable
Medicinal Rating
Other Uses Rating
Habit	Deciduous Tree
Height	30.00 m
Pollinators	Bees, Moths
Cultivation Status	Cultivated, Ornamental, Wild

Cultivation Details

A plant of low to mid elevations in moist tropical regions, being found at elevations up to 1,400 metres in areas where the annual rainfall is in the range 1,200 - 1,800 mm, and there is a dry season of 3 - 5 months[].
Prefers a moist but well-drained soils[]. In the wild it is locally common on alluvial soils in valleys[].
The growth rate of young trees can be quite good. In Nigeria saplings reached an average height of 4.2 metres, and a bole diameter of 7 cm, 4 years after planting[]. Trees planted in the open in the semi-deciduous forest zone of Cote D'Ivoire reached an average height of 13.5 metres and an average bole diameter of 17 cm after 10 years[]. However, trees planted in the evergreen forest zone only reached 9 metres in height and 11.5 cm in diameter after 8 years[]. In Nigeria, an average height of 21 metres after 20 years was recorded[].
Seeds can germinate in full sun as well as in the shade, but natural regeneration may be very sparse in the forest where seedlings often show very poor growth and do not survive long[]. Natural regeneration can be abundant in savannah which is close to the forest and protected from fire[].
The presence of endotrophic mycorrhizal fungi in nurseries is important; inoculation with Endogone spores markedly improved the growth of seedlings[].

Edible Uses

None known

Medicinal

The bitter-tasting bark is used in traditional medicine. It is widely used as a treatment against fever caused by malaria, whilst decoctions are also taken to treat stomach complaints including gastric ulcers and diarrhoea caused by intestinal parasites; pain after childbirth; and gonorrhoea[].
The pulverized root bark is applied externally to treat skin diseases[].

Research carried out has shown that bark extracts exhibit antimalarial activity. Several limonoids isolated from the bark and seeds have shown distinct antimalarial activity against chloroquine-resistant strains of Plasmodium falciparum, particularly gedunin, 7-deacetylkhivorin, methylangolensate and 6-acetylswietenolide[]. The most active limonoid, gedunin, exhibited an additive effect when combined with chloroquine[].
The bark extracts have also shown hypoglycaemic, hypoproteinaemic and hypocholesterolaemic effects, giving good results for the treatment of gastric ulcers[]. They had positive effects on the production of red blood cells[].

Agroforestry Uses:

The tree is planted along the banks of rivers in order to stabilize them[].

Other Uses

The bark is used for washing cloth[].

A gum obtained from the bark is extremely resistant to hydrolysis and highly acidic (pH 3.0 - 4.0)[]. It contains the sugars rhamnose, arabinose and galactose, as well as glucuronic acid and galacturonic acid[]. Research has shown that the gum can serve as a useful formulating agent in the pharmaceutical industry. It showed good properties for sustained-release tablets for up to 5 hours, whereas a combination with hydroxypropylmethylcellulose could be used to provide a release for longer periods[]. The gum was effective as a coating to extend the storage life of cassava roots, and it could also be used as ice cream stabilizer[].

Extracts from the plant have shown pesticidal properties[]. Bark extracts showed nematicidal activity against Pratylenchus brachyurus, a nematode injurious to many crops worldwide[]. They inhibited egg-hatch in sugarcane cyst nematode (Heterodera sacchari)[]. Bark and seed extracts showed toxic effects on Aedes aegypti mosquitoes[]. Seed extracts resulted in high mortality in the cotton stainer (Dysdercus sp.)[].
The mexicanolide-type limonoids isolated from the seeds showed antifeedant activity against larvae of the Mexican bean beetle (Epilachna varivestis), a notorious pest of beans and other leguminous crops[].
Bark and seed extracts, as well as the limonoids khivorin isolated from the bark and fissinolide isolated from the seed, have molluscicidal properties[].

The heartwood is pinkish brown, darkening to reddish brown upon exposure, and is usually distinctly demarcated from the 3 - 8cm wide band of pale brown to pinkish brown sapwood, at least in the dried wood. The texture is medium to rather coarse; the grain is usually interlocked, sometimes straight. Wood from savannah trees is reported to be darker than that of forest trees[]. The wood is light to moderately heavy; soft to moderately hard; moderately durable, being resistant to dry wood borers, fairly resistant to fungi, but susceptible to termites. It generally air dries rather slowly, but with little degrade; rates of shrinkage are moderate; once dry, the wood is stable in service[]. The wood is fairly easy to saw and work, with a moderate blunting effect on cutting edges; it can be finished to a smooth surface and takes an excellent polish; it holds nails and screws well, but it has some tendency to split; it has good gluing properties. The peeling properties are poor because of the higher density in comparison with Khaya anthotheca and Khaya ivorensis and the interlocked grain, but slicing gives a decorative veneer. The wood is valued for carpentry, joinery, furniture, cabinet work and decorative veneer. It is suitable for light construction, light flooring, interior trim, ship building, musical instruments, toys, novelties, carving, turnery and pulpwood[, ]. Traditionally, the wood is used for furniture, household implements and dug-out canoes[].
The wood is also used as fuel wood and for charcoal production[].

Propagation

Seed - does not require pre-treatment. It is best sown in seed beds in the nursery or in pots[]. Upon sowing, the seeds should be covered with only a thin layer of soil, or left partially uncovered, but should not be allowed to dry out[]. Germination takes 10 - 35 days - fresh healthy seeds have a high germination rate of about 90%, but this decreases rapidly to nearly zero after 2 months under natural circumstances[].
It has been recommended to provide light shade to young seedlings until they are 1 - 2 months old, but in Nigeria it was found that seedlings grew best with full light, watering at least every second day[]. Seedlings can be left in the nursery for about one year until they are 0.5 - 1 metre tall, after which the root system is pruned to a length of about 30 cm and most leaves stripped off before planting into the field[].
The seeds are often already attacked by insects while they are still on the tree, and undamaged seeds should therefore be selected before sowing[]. The seeds can be stored in a cool place; it is recommended to add ash during storage to reduce insect attacks[].

Add a Comment:

If you have any useful information about this plant, please leave a comment. Comments have to be approved before they are shown here.

Name:

Email(Private):

Message:

Captcha: a square has how many sides?