KHAYA IVORENSIS PDF

KHAYA IVORENSIS PDF

The tree is widely exploited for its very valuable timber, which is traded internationally, and plantations have been established in several countries. A high. Identity. Top of page. Preferred Scientific Name. Khaya ivorensis A. Chev. Preferred Common Name. African mahogany. International Common. Khaya ivorensis is distributed from Côte d’Ivoire east to Cameroon and south to Cabinda (Angola); it possibly also occurs in Guinea, Liberia.

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It is fairly widely grown in plantations within its natural area of distribution, but also in tropical Asia and tropical America. The wood trade names: It is suitable for light construction, light flooring, ship building, vehicle bodies, handles, ladders, sporting goods, musical instruments, toys, novelties, precision equipment, carving, turnery and pulpwood. The wood is in demand for making backs or sides of acoustic guitars as it is considered to have good acoustical characteristics.

Traditionally, the wood is used for dugout canoes. It is also used as fuelwood and for charcoal production. The bitter-tasting bark is widely used in traditional medicine. Bark decoctions are taken to treat cough, fever and anaemia, and are applied externally to wounds, sores, ulcers and tumours, and as an anodyne to treat rheumatic pains and lumbago. Root pulp is applied as an enema to treat dysentery. Ground young shoots and leaves are applied externally as an anodyne.

The seeds are used in soap production. In Nigeria Khaya ivorensis trees are locally retained in cocoa plantations to serve as shade trees and ultimately for timber production. Khaya ivorensis wood is exported from West African countries in mixed consignments with other Khaya spp. The proportion of Khaya ivorensis in these amounts is obscure.

In recent years, the United States market has dominated the international trade in Khaya timber, especially as a substitute for American mahogany from Swieteniathe availability of which has declined considerably.

The heartwood is pale pinkish brown to pale red, darkening to deep brown with a golden lustre upon exposure. It is more or less distinctly demarcated from the creamy white, up to 5 cm wide sapwood. The grain is straight or interlocked, texture rather coarse.

It generally air dries and kiln dries easily with little degrade, but some warping may occur due to the presence of interlocked grain. The rates of shrinkage are moderate, from green to oven dry 2. Once dry, the wood is fairly stable in service. The wood is usually fairly easy to saw and work, although the presence of interlocked grain may cause some difficulties. The wood can be finished to a smooth surface, but the use of a filler is required in staining and varnishing.

The wood holds nails and screws well and glues satisfactorily. The bending properties are poor. The wood peels and slices well, producing an excellent quality of veneer. It turns fairly well. The wood dust may cause irritation to the skin. The wood is moderately durable and can be susceptible to termite and pinhole borer attacks. The heartwood is strongly resistant to impregnation, the sapwood moderately resistant.

The wood is suitable for paper production, and even peeler cores, often regarded as waste, are suitable for pulp production. Limonoids have been isolated from the bark and seeds.

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Some of these showed significant antifeedant activity in insects, and some antifungal and antibacterial activities. Bark extracts showed weak antitrypanosomal and antiplasmodial activities in tests with mice.

Tests in rats showed that the bark has dose-dependent anti-inflammatory activity and that it is toxic only at high doses. The bark showed anticonvulsant activity in mice.

The oil can be used as an additive in liquid soaps, and may act as an antibacterial and antifungal agent because of the presence of limonoids such as methylangolensate. Smoke from the wood showed good results in tests of smoking fish, protecting the fish effectively against fungi.

The wood of Khaya anthotheca is very similar to that of Khaya ivorensis.

The wood of both species and that of Khaya grandifoliola C. The wood of makore Tieghemella is similar, but more durable. Khaya comprises 4 species in mainland Africa and 1 or 2 endemic to the Comoros and Madagascar.

It belongs to subfamily Swietenoideae and seems most closely related to Carapa and Swietenia. Khaya species strongly resemble each other in flowers and fruits, and differences are most prominent in their leaflets. There appears to be a more or less gradual transition in species according to ecological gradients, from the moist evergreen forest zone through semi-deciduous forest to the savanna zone.

Trees planted in the open in the evergreen forest zone reached an average height of 12 m and an average bole diameter of 15 cm after 8 years. In mixed plantations the average bole diameter was 39 cm at 27 years after planting, with dominant trees being 28 m tall and 47 cm in diameter. At 34 years after planting dominant trees were 76 cm in diameter, but the bole was branchless for only 12 m.

In Nigeria the average height of saplings was 4. In year-old plantations in Malaysia, a mean annual increment of 1. In a year-old plantation in Malaysia, trees had an average height of Young trees have a slender stem and a small crown. Extensive lateral growth starts when the upper canopy of the forest has been reached.

The monoaxial state may persist to a height kuaya 10 m. Trees are sometimes leafless for a short period at the beginning of the dry season. In moist evergreen forest Khaya ivorensis can be found flowering and fruiting throughout the year and bearing flowers and fruits at the same time; usually flowering is seasonal, in West Africa icorensis most abundant in June—October.

Fruits mature in about 6 months. Trees of 30 years old may produce fruits and seeds abundantly. Mass production of seeds is reported to occur every 3—4 years. Dispersal of the seeds is by wind, but most seeds fall close to the parent tree. Khaya ivorensis is most abundant in evergreen forest, but can also be found in moist semi-deciduous forest, in areas with — mm annual rainfall and a dry season of 2—3 months, up to m altitude.

In moist semi-deciduous forest it may occur khays with Khaya anthotheca.

iorensis Khaya ivorensis often occurs along watercourses. It prefers alluvial soils khaay are moist but well-drained, but it can also be found on slopes on lateritic soils. Seeds can germinate in full sun as well as in the shade, but natural regeneration is apparently sparse in large gaps.

Seedlings can survive in dense shade, but for good growth opening of the forest canopy is needed. Regeneration of Khaya ivorensis is not promoted by large disturbances in the forest, but it benefits from small gaps. Khaya ivorensis is propagated by seed. The seed weight is — g. The seeds are often already attacked by insects while they are still on the tree, and undamaged seeds should therefore be selected before sowing.

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The seeds are best sown in seed beds in the nursery. Germination is rather slow, taking 11—40 days. In the nursery, light shade is advantageous for seedlings up to 2 years old; this reduces attacks by Hypsipyla shoot borers and the development of leaf galls. The application of 0. Seedlings are planted out when 60—90 cm tall, usually as stumps or striplings.

Later it was planted in lines as enrichment of degraded forests, mixed with other species, at a distance of 7—25 m between lines and 3—7 m within the line, and some trees showed an annual diameter growth of over 2. More recently it has been planted successfully in 3 ivoreensis to mark the boundary of forestry reserves. Khaya ivorensis occurs scattered or in small groups in the forest, usually in low densities. In southern Cameroon on average 0.

Khaya ivorensis (PROTA) – PlantUse English

In Gabon 4-month-old seedlings have been planted after clear-cutting of the forest, and in other sites after removal of the forest undergrowth and khaha of the upper canopy.

Average heights were After 11 years average heights were Regular thinning of the shade trees in the first years is needed for good growth of the Khaya ivorensis trees. In tropical Africa Khaya ivorensis has been planted successfully in mixed plantations, e.

Roberty and Triplochiton scleroxylon K. Realistic rotation cycles in natural forest are probably in the range of 60—80 years.

IUCN Red List of Threatened Species

In plantations Khaya ivorensis may suffer seriously from Hypsipyla robusta shoot borers that kill the main stem of young trees, causing excessive branching and contributing to mortality.

Silvicultural techniques such as overhead shading of saplings, mixed planting and removal of lateral shoots can reduce damage by shoot borers. In Brazil Khaya ivorensis is used for reforestation because of its resistance to Hypsipyla grandellathe major pest of Brazilian mahogany. Seeds are commonly attacked by seed-boring beetles and eaten by small rodents.

Attacks of living trees by wood borers Apate spp. The bark of saplings is sometimes eaten by porcupines and squirrels, which can kill the plants. The boles of Khaya ivorensis trees are occasionally so large that they cannot be sawn with normal equipment. The high buttresses at the base of the bole often necessitate the construction of a platform before felling can take place, or the removal of the buttresses before felling to recover more timber.

A natural forest tree with a bole diameter of 80 cm yields on average 6. In 26—year-old plantations in Malaysia, mean annual increments of 7.

Khaya ivorensis

Logs may have a spongy or brittle heart, and care is needed in felling and sawing operations. They are susceptible to attack by longhorn beetles and should be processed not too long after felling.

The sapwood is often removed soon after felling to prevent attacks by ambrosia beetles.