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Biology

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The azobe sheds all its leaves during a short period of one to two weeks, usually in December, and the re-growth of bright red young leaves, often simultaneously on all azobe trees in an area, can set the canopy ablaze with colour (2). The flowers of the azobe are white, fairly large, strong-smelling, and grouped in loose, branched, terminal inflorescences. Flowering occurs in adult trees with trunks over 50 centimetres in diameter, and takes place from the time the new leaves appear. Azobe is monoecious, meaning that male and female flowers are found on the same tree, and the flowers are insect-pollinated (2) (4) (6). Fruiting takes place between January and March, the fruits becoming mature around March to April, although fruits do not always appear every year (2). The fruits, which are wind-dispersed, contain a single, oil-rich seed in a conical capsule, which is brown when mature and is surrounded by two unequally-sized membranous 'wings', one up to six centimetres long and the other twice the size, at up to twelve centimetres (2) (4) (7). Although the azobe needs full sunlight to grow (2) (7), seedlings can persist for some time in the shady undergrowth and resume growth if and when sunlight again becomes available (2).
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Conservation

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The azobe is protected by law in Ivory Coast (7), and occurs in protected areas in some parts of its range, such as in Odzala National Park in Congo (9). However, improved protection, better management of existing forest reserves, and intensified regeneration work are all considered essential conservation measures to protect this heavily utilised rainforest tree (1) (7).
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Description

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The alternative name for this large rainforest tree, 'ironwood', refers to the very heavy and hard nature of its valuable timber (2) (3). The trunk of the azobe is usually straight, without buttresses, but sometimes with a swollen base (2) (4) (5), and is usually clear of branches up to about 30 metres (5). The bark is typically red-brown in colour, up to two centimetres thick, and has a bright yellow layer underneath. Young trees under four metres in height have greenish-grey bark, which becomes pink or light brown as the tree matures (2). Inside, the living sapwood is pale pink or whitish in colour, while the inner heartwood is dark red-brown to chocolate brown, with conspicuous white deposits of silica (2) (4) (5). The leaves of the azobe are up to 25 centimetres long and are tough, fairly narrow and elongated, with a rounded or slightly indented tip, and tend to occur in clusters at the ends of the twigs (2) (4).
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Habitat

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Found in wet evergreen forest, moist deciduous forest, freshwater swamp forest and gallery forest, azobe is a pioneer species, able to colonise open and disturbed areas, such as forest edges, clearings, the sides of roads and rivers, and even savannas and abandoned cultivated areas (1) (2) (7). Azobe adapts to a range of soil types and tends to prefer fairly flat ground, generally at elevations below 800 metres (2).
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Range

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Azobe occurs in western and central Africa, from Sierra Leone to Ghana, and in Nigeria, Cameroon, Congo, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Sudan and Uganda (1) (6) (7).
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Status

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Classified as Vulnerable (VU) on the IUCN Red List (1).
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Threats

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Although common and widespread in Cameroon, where it regenerates well (1) (7), azobe is under threat in other parts of its range as a result of large-scale forest destruction and over-exploitation for its timber (1), which is popular for heavy construction work, harbour works and railway sleepers (2) (3) (7). The species is also used locally in traditional medicine, for treating backache, toothache, respiratory and stomach problems, and as a treatment for yellow fever. The leaves can be used in mulch to help control termites, and an edible and odourless oil from the seeds is used as a food and to make ointments and soaps (2) (7) (8). This heavy exploitation, together with azobe's slow growth rate and poor regeneration when conditions are not optimum, is contributing to a population decline throughout most of its range (1).
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Comprehensive Description

provided by Smithsonian Contributions to Botany
Lophira alata Banks ex C. F. Gaertner

Standard trade name: Ekki

Local names: Kaku (Ghana), Eba (Nigeria), Azobe (France and French-speaking West Africa)

Ekki may reach a height of 160 ft to 180 ft and a diameter of more than 6 ft at breast height. The bole has no buttresses but the basal swelling may extend for some 12 ft up the trunk. The bole is often free of branches for 80 to 100 ft. Crown triangular, bark reddish brown, peeling in loose flakes, slash red, leaves shorter, broader, and more obovate than those of savanna form (Irvine, 1961), petioles also shorter. Flowers white or golden yellow. Fruits over one inch long, pointed, nearly ½ in wide, broader than those of L. lanceolata, wing also much shorter, about ½ in long (Irvine, 1961:91).

GENERAL DESCRIPTION.—Ekki is outstanding for its hardness and weight, weighing from 56 to 71 lb/ft3 at 12% MC The green weight is about 77 lb/ft3 at 45% MC. The specific gravity ranges from 0.74 to 0.97 based on volume when green and ovendry weight. Heartwood is red or deep chocolate brown with a mottled appearance due to conspicuous white deposits in the pores. The sapwood is paler in color and about 2 in in width. The grain is usually interlocked; the texture coarse and uneven.

SEASONING.—It is an extremely refractory species. Not only does it dry very slowly, but severe splitting and some distortion are likely to occur during seasoning. It needs to be stacked with special care. British Forest Products Laboratory kiln schedule B is recommended for this species (FPRL, 1956).

DURABILITY.—Damage by ambrosia (pinhole borer) beetles is occasionally present. It is resistant to, though not immune from, attack by termites. Ekki is rated the most durable timber on the west coast of Africa. Maritime structures in France, Belgium, and Holland have remained intact after more than 20 years of service. Piers were found in excellent condition after 12 years of standing in brackish water infested with teredos (Forest Products Laboratory, 1965). In temperate climates the wood is almost rot-proof. It is extremely resistant to preservative treatment.

WORKING QUALITIES.—The timber is difficult to work with hand and machine tools. Dry material blunts cutting edges fairly quickly but the blunting effect of green material is not so severe. Some tearing occurs in planing with the normal cutting angle of 30°, but the finish is usually satisfactory. The timber tends to char in boring. It cannot be nailed without preboring. It has variable but generally good gluing properties.

USES.—The high durability and hardness of ekki make it particularly suitable for pilings. It is regarded as superior to reinforced concrete for all hydraulic works or structures, such as landing stages, piling, wharves, dams, or locks. In Africa it is used untreated for sleepers and for construction work, such as bridges. It is a good heavy-duty flooring timber for warehouses and factories where a very smooth surface is not essential.

XYLEM ANATOMY.—Growth rings absent. Wood diffuse-porous. Vessels: mostly solitary, others in multiples of 2 or 3, oval; average pore diameter 196μm, range 98μm–244μm; average vessel length 308μm, range 210μm–560μm; vessel wall thickness 4μm; perforation plates simple; vessel element end wall inclination slightly oblique to transverse; intervascular pitting alternate. Imperforate tracheary elements: average length 1250μm, range 1150μm–2300μm. Vascular rays: homogeneous mostly multi-seriate, 2 to 4 cells wide, 8 to 26 cells high; uniseriate and biseriate also present but few. Axial parenchyma: paratracheal, tendency towards aliform. Tanniferous material present in some vessels.

RUBIACEAE (NAUCLEACEAE)
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bibliographic citation
Ayensu, Edward S. and Bentum, Albert. 1974. "Commercial Timbers of West Africa." Smithsonian Contributions to Botany. 1-69. https://doi.org/10.5479/si.0081024X.14

Lophira alata

provided by wikipedia EN

Lophira alata, commonly known as azobé, ekki or the red ironwood tree, is a species of plant in the family Ochnaceae. It is found in Cameroon, the Republic of the Congo, the Democratic Republic of the Congo, Ivory Coast, Equatorial Guinea, Gabon, Ghana, Liberia, Nigeria, Sierra Leone, Sudan, and Uganda. Its natural habitat is subtropical or tropical moist lowland forests. It is threatened by habitat loss.

The timber is extremely hard and used for railroad ties, groynes and bridge planking.

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Lophira alata used as the pavement of wooden footbridge in Wrocław (Poland)

Description

The trunk of Lophira alata is usually straight, without buttress roots, but sometimes with a swollen base, and is usually clear of branches up to about 30 metres (98 ft). The bark is typically red-brown in colour, up to two centimetres thick, and has a bright yellow layer underneath. Young trees under four metres in height have greenish-grey bark, which becomes pink or light brown as the tree matures. Inside, the living sapwood is pale pink or whitish in colour, while the inner heartwood is dark red-brown to chocolate brown, with conspicuous white deposits of silica. The leaves of L. alata are up to 25 centimetres (9.8 in) long and are tough, fairly narrow and elongated, with a rounded or slightly indented tip, and tend to occur in clusters at the ends of the twigs.[2]

Biology

Lophira alata sheds all its leaves during a short period of one to two weeks, usually in December, and the re-growth of bright red young leaves, often simultaneously on all L. alata trees in an area, can set the canopy ablaze with colour. The flowers of L. alata are white, fairly large, strong-smelling, and grouped in loose, branched, terminal inflorescences. Flowering occurs in adult trees with trunks over 50 centimetres in diameter, and takes place from the time the new leaves appear. L. alata is monoecious, meaning that male and female flowers are found on the same tree, and the flowers are insect-pollinated. Fruiting takes place between January and March, the fruits becoming mature around March to April, although fruits do not always appear every year. The fruits, which are wind-dispersed, contain a single, oil-rich seed in a conical capsule, which is brown when mature and is surrounded by two unequally-sized membranous ‘wings’, one up to six centimetres long and the other twice that size. Although L. alata needs full sunlight to grow, seedlings can persist for some time in the shady undergrowth and resume growth if breaks in the canopy occur.[2]

Uses

The timber, known as azobe, is strong and resistant making it useful for demanding constructions outdoors. The timber also has better electrical properties than other wood making it possible to use it in poles for electric fences without separate isolators. The colour is reddish brown and the wood is abrasive, dulling tools rapidly.

Sniffing the bark is used as a traditional treatment for headache. The leaves of Lophira alata afforded two new biflavonoids, lophirone L (1) and lophirone M (2), and the known luteolin and lithospermoside. Both biflavonoids were obtained in small quantities, and their structures show some new and unusual biflavonoid diversity.[3] Likewise, two chalcone tetramers were isolated as inhibitors of Epstein-Barr virus (EBV)-activation induced by a tumor promoter, teleocidin B-4, from Lophira alata. One of them was identified as lophirachalcone. The other, named alatachalcone, was new, and the structure was determined by spectral properties. Both compounds also showed potent inhibitory activities against teleocidin B-4-induced inflammation on mouse ear. In an initiation-promotion experiment on mouse skin, alatachalcone (16 nmol) significantly inhibited tumor promotion caused by 12-O-tetradecanoylphorbol-13-acetate (TPA, 1.6 nmol).[4]

References

This article incorporates text from the ARKive fact-file "Lophira alata" under the Creative Commons Attribution-ShareAlike 3.0 Unported License and the GFDL.

  1. ^ a b African Regional Workshop (Conservation & Sustainable Management of Trees, Zimbabwe) 1998. Lophira alata. 2006 IUCN Red List of Threatened Species. Downloaded on 22 August 2007.
  2. ^ a b Azobé Retrieved 2011-08-24
  3. ^ J Nat Prod. 2006 Aug;69(8):1206-8. Tih AE, Ghogomu RT, Sondengam BL, Caux C, Bodo B. University of Yaounde I, P.O. Box 812, Yaounde, Cameroon.
  4. ^ Biosci Biotechnol Biochem. 1992 May;56(5):769-72. Chalcone tetramers, lophirachalcone and alatachalcone, from Lophira alata as possible anti-tumor promoters. Murakami A, Tanaka S, Ohigashi H, Hirota M, Irie R, Takeda N, Tatematsu A, Koshimizu K. Department of Food Science and Technology, Faculty of Agriculture, Kyoto University, Japan.

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Lophira alata: Brief Summary

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Lophira alata, commonly known as azobé, ekki or the red ironwood tree, is a species of plant in the family Ochnaceae. It is found in Cameroon, the Republic of the Congo, the Democratic Republic of the Congo, Ivory Coast, Equatorial Guinea, Gabon, Ghana, Liberia, Nigeria, Sierra Leone, Sudan, and Uganda. Its natural habitat is subtropical or tropical moist lowland forests. It is threatened by habitat loss.

The timber is extremely hard and used for railroad ties, groynes and bridge planking.

 src= Lophira alata used as the pavement of wooden footbridge in Wrocław (Poland)
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