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Entandrophragma utile (Dawe & Sprague) Sprague

Protologue
Bull. Misc. Inform. Kew 1910: 180 (1910).
Family
Meliaceae
Chromosome number
2n = 72
Vernacular names
Sipo mahogany, African cedar, heavy mahogany, brown mahogany (En). Sipo, acajou sipo, acajou assim (Fr).
Origin and geographic distribution
Entandrophragma utile is widespread, occurring from Sierra Leone east to Uganda, and south to DR Congo and Angola.
Uses
The wood, usually traded as ‘sipo’ or ‘utile’, is highly valued for exterior and interior joinery, interior trim, panelling, stairs, furniture, cabinet work, ship building, veneer and plywood. It is suitable for construction, flooring, vehicle bodies, boxes, crates, carvings and turnery. The bole is traditionally used for dug-out canoes. Wood that can not be valorised as timber may be used as firewood and for charcoal production.
The bark is used in traditional medicine in Central Africa. Bark sap is taken or used as a wash to treat stomach-ache and kidney pain, it is rubbed in to relieve rheumatism, and it is dropped into the eyes to treat eye inflammations and into the ear to treat otitis. A massage with a bark maceration is considered useful as tonic and stimulant. Charred and pulverized bark, mixed with salt and palm oil, is rubbed into scarifications to treat headache. In Cameroon the bark is used to treat malaria. In Nigeria the bark is claimed to heal peptic ulcers. The fruit valves have been used as spoons.
Production and international trade
In Côte d’Ivoire sipo was formerly a very important export timber: in 1964–1972 mean annual exports were 590,000 m³ of logs and 66,000 m³ of sawn wood. Exports fell after 1973, to only 56,000 m³ of logs in 1983. Presently, sipo is still an important export timber, mainly from the Central African Republic and Congo. In 2003 the Central African Republic exported 6000 m³ of Entandrophragma utile logs in 2003, at an average price of US$ 503/m³, and 1000 m³ of sawn wood, at an average price of US$ 693/m³. Congo exported 38,000 m³ of logs in 2003, at an average price of US$ 253/m³, 43,000 m³ in 2004, at an average price of US$ 246/m³, and 33,000 m³ in 2005, at an average price of US$ 247/m³. Sawn wood exports from Congo in 2004 and 2005 were 10,000 m³ (at US$ 333/m³) and 13,000 m³ (at US$ 316/m³), respectively. The export of veneer from Congo was 1000 m³ in 2004, at an average price of US$ 317/m³. Entandrophragma utile is an important timber species of Ghana for export.
Properties
The heartwood is reddish brown to purplish brown, and distinctly demarcated from the pinkish white to pale brown, up to 6 cm wide sapwood. The grain is slightly interlocked, texture moderately fine. Quarter-sawn surfaces are irregularly striped. The wood has a faint cedar-like smell.
The wood is medium-weight, with a density of (400–)550–690(–740) kg/m³ at 12% moisture content. It air dries rather slowly, and may be liable to splitting and distortion. However, there seems to be considerable variation in drying characteristics. The risk of distortion during drying increases when more highly interlocked grain is present. The wood kiln dries satisfactorily, but material with much interlocked grain may give difficulties. The rates of shrinkage are medium, from green to oven dry (2.9–)3.7–6.4% radial and (4.0–)5.4–9.2% tangential. Once dry, the wood is moderately stable in service.
At 12% moisture content, the modulus of rupture is 83–152 N/mm², modulus of elasticity 8830–13,830 N/mm², compression parallel to grain 45–72 N/mm², shear 5–17 N/mm², cleavage 11–23 N/mm, Janka side hardness 3330–5610 N and Janka end hardness 5250–7960 N.
The wood saws and works fairly easily with both hand and machine tools, with only slight blunting effects on cutting edges. In planing and moulding operations, a 15–20° cutting angle is recommended to avoid picking up of grain. Finishing usually gives good results, with a nice polish, but the use of a filler may be needed. The wood is not liable to splitting in nailing and screwing, with good holding properties. The gluing, staining and polishing properties are satisfactory, but the steam bending properties are poor. A tendency of charring is present in drilling operations. The wood is suitable for veneer production, both by rotary peeling as well as slicing; steaming for 48–72 hours at 85°C gives good results. The wood is moderately durable, being moderately resistant to powder-post beetle, pinhole borer, termite and marine borer attacks. The heartwood is very resistant to preservatives.
An aqueous bark extract showed significant protection against ethanol-induced peptic ulcers in rats at a very high oral dose of 50 g/kg, without lethality. This supports the traditional medicinal use of the bark against peptic ulcers in Nigeria. Bark extracts showed fungicidal activity against Pyricularia oryzae. The lactone entandrophragmin, tetranortriterpenoids called utilins, heptanortriterpenoids called entilins, methyl angolensate and an ergosterol derivative have been isolated from the bark. Some entilins showed moderate in-vitro antimalarial activity against chloroquine-resistant strains of Plasmodium falciparum. The seeds contain 30–54% of fat by weight. The fatty acid composition is characterized by the presence of about 30% cis-vaccenic acid, a rare isomer of oleic acid that can be used in the industrial production of nylon-11. The main fatty acid is linolenic acid (46%). The seeds contain limonoids and steroids, but no tannins and saponins.
Adulterations and substitutes
The wood of Entandrophragma cylindricum (Sprague) Sprague, traded as ‘sapelli’ or ‘sapele’, resembles that of Entandrophragma utile, but is often more nicely coloured and figured.
Description
Deciduous, dioecious large tree up to 55(–65) m tall; bole branchless for up to 40 m, straight and cylindrical, up to 200(–300) cm in diameter, with blunt buttresses up to 3(–5) m high, sometimes extending into large surface roots; bark surface silvery grey to greyish brown or yellowish brown, fissured and becoming scaly with elongate scales, inner bark pinkish red, fibrous, without distinct smell; crown dome-like, with few but massive branches; young twigs brownish short-hairy but soon glabrescent, marked with leaf scars. Leaves alternate, clustered near ends of twigs, paripinnately compound with (12–)14–32 leaflets; stipules absent; petiole 5–15 cm long, with 2 faint lateral ribs or slightly winged at base, rachis up to 45 cm long, slightly grooved; petiolules 1–5 mm long; leaflets opposite to alternate, oblong-elliptical to oblong-lanceolate or oblong-ovate, (3.5–)5–15 cm × (1.5–)2–5.5 cm, rounded to slightly cordate and asymmetrical at base, usually short-acuminate at apex, papery to thinly leathery, almost glabrous but with tufts of hairs in vein axils below, pinnately veined with 10–16 pairs of lateral veins. Inflorescence an axillary or terminal panicle up to 25 cm long, short-hairy. Flowers unisexual, regular, 5-merous; pedicel 2–3 mm long; calyx cup-shaped, shortly lobed, 0.5–1 mm long, short-hairy outside; petals free, ovate, 5–6 mm long, short-hairy outside, greenish white; stamens fused into an urn-shaped tube 3–4 mm long, with 10 anthers at the slightly toothed or nearly entire apex; disk cushion-shaped, small; ovary superior, conical, 5-celled, style c. 1.5 mm long, stigma disk-shaped; male flowers with rudimentary ovary, female flowers with smaller, non-dehiscing anthers. Fruit a pendulous, club-shaped capsule 14–28 cm × 4.5–7 cm, brownish black and with numerous reddish brown lenticels, dehiscing from the apex with 5 woody valves, up to 30-seeded with seeds attached to the upper part of the central column. Seeds 8–11 cm long including the large apical wing, medium to dark brown. Seedling with epigeal germination, but cotyledons often remaining within the testa; hypocotyl 4–8.5 cm long, epicotyl 2–4 cm long; first 2 leaves opposite, simple.
Other botanical information
Entandrophragma comprises about 10 species and is confined to tropical Africa. It belongs to the tribe Swietenieae and is related to Lovoa, Khaya and Pseudocedrela.
Anatomy
Wood-anatomical description (IAWA hardwood codes):
Growth rings: (1: growth ring boundaries distinct); (2: growth ring boundaries indistinct or absent). Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; (23: shape of alternate pits polygonal); 24: intervessel pits minute ( 4 μm); 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 42: mean tangential diameter of vessel lumina 100–200 μm; (43: mean tangential diameter of vessel lumina 200 μm); 46: 5 vessels per square millimetre; (47: 5–20 vessels per square millimetre); 58: gums and other deposits in heartwood vessels. Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 65: septate fibres present; 66: non-septate fibres present; 69: fibres thin- to thick-walled. Axial parenchyma: 78: axial parenchyma scanty paratracheal; 79: axial parenchyma vasicentric; 80: axial parenchyma aliform; 82: axial parenchyma winged-aliform; 83: axial parenchyma confluent; (85: axial parenchyma bands more than three cells wide); 86: axial parenchyma in narrow bands or lines up to three cells wide; (89: axial parenchyma in marginal or in seemingly marginal bands); 92: four (3–4) cells per parenchyma strand; 93: eight (5–8) cells per parenchyma strand. Rays: 97: ray width 1–3 cells; 104: all ray cells procumbent; 106: body ray cells procumbent with one row of upright and/or square marginal cells; 115: 4–12 rays per mm. Storied structure: (118: all rays storied); (122: rays and/or axial elements irregularly storied). Secretory elements and cambial variants: 131: intercellular canals of traumatic origin. Mineral inclusions: (136: prismatic crystals present); (137: prismatic crystals in upright and/or square ray cells); (141: prismatic crystals in non-chambered axial parenchyma cells); (142: prismatic crystals in chambered axial parenchyma cells).
(L.N. Banak, H. Beeckman & P.E. Gasson)
Growth and development
Young seedlings grow slowly; root development takes considerable time. In Ghana seedlings reached only up to 1 m tall after 4 years, in silviculturally treated forest up to 1.5 m. Under nursery conditions, however, seedlings can reach 40 cm tall in 6 months and 75 cm in one year. Fruit production starts when trees have reached bole diameters above 50 cm, and this has implications for forest management; minimum felling diameters should be well above 50 cm to allow natural regeneration. In Liberia and Côte d’Ivoire trees are deciduous for variable periods between November and March; flowers occur together with the new leaves. Fruits mature at the end of the dry season, about one year after flowering. Fruits often fall unopened. However, they usually open on the tree and the seeds are dispersed by wind, although most seeds seem to fall close to the mother tree.
Ecology
Entandrophragma utile is most common in moist semi-deciduous forest, particularly in regions with an annual rainfall of 1600–1800 mm, a dry period of 2–4 months and mean annual temperature of 24–26°C. However, it can also be found in evergreen forest. In Uganda it occurs in rainforest at 1100–1400 m altitude. It prefers well-drained localities on deep soils.
Entandrophragma utile is characterized as a non-pioneer light demander. Natural regeneration is often scarce in natural forest, but it has also been reported as abundant. Regeneration in large forest gaps is reportedly poor, but seedlings perform well in small forest gaps. Saplings of Entandrophragma utile are more light-demanding than those of other Entandrophragma spp.
Propagation and planting
The 1000-seed weight is about 500 g. Seeds can be stored for about 3 months in sealed containers in a cool place, but insect damage, to which they are very susceptible, should be avoided, e.g. by adding ash. Fresh seeds have a germination rate of about 75%, and that of 3-month-old seeds is still about 60%. Germination starts 13–19 days after sowing. Repeated soaking of the seeds is reported to improve germination. The seeds are liable to rotting and should hardly be covered with soil. Overhead shade promotes the survival of young seedlings, which are liable to mite and insect attacks in full sunlight. The seedlings usually die under full light conditions. They are physiologically well adapted to heavy shade and make efficient use of low light intensities. Seedlings growing in 10–12% of full sunlight maintained high growth rates, and an irradiance of 25% of full sunlight is recorded to optimize growth of young seedlings. When seedlings are grown in pots, it should be taken into account that they develop a long taproot; roots should be cut back several times in the 1–2-year-long period that the seedlings are raised in the nursery. Stumps and striplings have been used for propagation, but the success rate of stumps was low.
Management
In several regions in Côte d’Ivoire an average of one exploitable Entandrophragma utile tree per 7–8 ha has been recorded in the 1950s. Locally in Liberia, one tree of more than 60 cm bole diameter per 6 ha can be found. In southern Cameroon exploitable trees occur very scattered; the average density is up to one tree of more than 60 cm bole diameter per 20 ha, and the average wood volume is up to 0.5 m³/ha. In Gabon Entandrophragma utile is uncommon, in most regions even rare. In Côte d’Ivoire timber plantations of Entandrophragma utile have been established, 1535 ha in the period 1968–1978.
Diseases and pests
In Uganda high mortality of seedlings has been recorded, due to predation by rodents, antelopes and Hypsipyla robusta shoot borers, but also to drought, with only slightly more than 1% of seedlings surviving after 2.5 years. Damage to seedlings due to Hypsipyla robusta shoot borer attack may be high in other countries as well. Larvae of the beetle Xylosandrus compactus bore into young shoots, while fruits and seeds are attacked by larvae of the lepidopterous insect Mussidia nigrivenella.
Harvesting
Minimum felling diameters are 60 cm in Côte d’Ivoire, 80 cm in Cameroon, the Central African Republic, Gabon and Congo, 100 cm in Liberia, and 110 cm in Ghana. In forests in Congo in the beginning of the 1990s Entandrophragma utile was selectively logged in a rotation of 30–40 years, together with Entandrophragma cylindricum (Sprague) Sprague and Triplochiton scleroxylon K.Schum.
Yield
On average a tree 1 m in diameter yields 10–13 m³ of commercial timber, and a tree 1.5 m in diameter 23–30 m³.
Handling after harvest
Freshly harvested logs float in water and can thus be transported by river.
Genetic resources
The commercial interest in the valuable timber of Entandrophragma utile has resulted in extraction of large individuals from the forest in many regions, e.g. in Côte d’Ivoire, Ghana, Nigeria, Cameroon, the Central African Republic and Uganda. In some regions it has even become near to extinction, e.g. in Uganda. It is included in the IUCN Red list as vulnerable.
Prospects
The low growth rates under natural conditions, the long time needed to reach maturity in terms of fruit production and poor dispersal ability of the seed seem to be serious drawbacks for sustainable management of Entandrophragma utile populations, making very long rotation cycles inevitable. It has been suggested that seed supplementation may be necessary to obtain sufficient regeneration in sustainably managed forest. Mycorrhizal inoculation seems to have potential for improving seedling establishment. It has also been suggested that intensive silviculture, possibly involving the use of shifting cultivation in a taungya-like system, is needed to achieve sustainable management. Entandrophragma utile does not seem to be a logical choice for planting in agroforestry systems because its early growth is too slow.
Major references
• Bolza, E. & Keating, W.G., 1972. African timbers: the properties, uses and characteristics of 700 species. Division of Building Research, CSIRO, Melbourne, Australia. 710 pp.
• Burkill, H.M., 1997. The useful plants of West Tropical Africa. 2nd Edition. Volume 4, Families M–R. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 969 pp.
• CAB International, 2005. Forestry Compendium. Entandrophragma utile. [Internet] http://www.cabicompendium.org/ fc/datasheet.asp?CCODE=ENT1UT. Accessed April 2008.
• CTFT (Centre Technique Forestier Tropical), 1973. Sipo. Bois et Forêts des Tropiques 150: 37–48.
• Hawthorne, W.D., 1995. Ecological profiles of Ghanaian forest trees. Tropical Forestry Papers 29. Oxford Forestry Institute, Department of Plant Sciences, University of Oxford, United Kingdom. 345 pp.
• Katende, A.B., Birnie, A. & Tengnäs, B., 1995. Useful trees and shrubs for Uganda: identification, propagation and management for agricultural and pastoral communities. Technical Handbook 10. Regional Soil Conservation Unit, Nairobi, Kenya. 710 pp.
• Styles, B.T. & White, F., 1991. Meliaceae. In: Polhill, R.M. (Editor). Flora of Tropical East Africa. A.A. Balkema, Rotterdam, Netherlands. 68 pp.
• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp.
• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.
• World Agroforestry Centre, undated. Agroforestree Database. [Internet] World Agroforestry Centre (ICRAF), Nairobi, Kenya. http://www.worldagroforestry.org/ resources/databases/ agroforestree. Accessed April 2008.
Other references
• ATIBT (Association Technique Internationale des Bois Tropicaux), 1986. Tropical timber atlas: Part 1 – Africa. ATIBT, Paris, France. 208 pp.
• Berti, S., Massei, M., Berti, R.N. & Topa, G., 1982. Tavole di cubatura di diciotto specie tropicali. Annali Accademia Italiana di Scienze Forestali 31: 345–380.
• Bonnet-Masimbert, M., 1972. L’enracinement de certaines essences de reboisement en Côte d’Ivoire (Sipo, Samba, Framiré, Niangon). Bois et Forêts des Tropiques 143: 23–34.
• CIRAD Forestry Department, 2003. Sipo. [Internet] Tropix 5.0. http://tropix.cirad.fr/africa/sipo.pdf. Accessed April 2008.
• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.
• Durand, P.Y., 1978. Propriétés physiques et mécaniques des bois de Côte d’Ivoire: moyennes d’espèce et variabilité intraspécifique. Centre Technique Forestier Tropical, Abidjan, Côte d’Ivoire. 70 pp.
• Farmer, R.H., 1972. Handbook of hardwoods. 2nd Edition. Her Majesty’s Stationery Office, London, United Kingdom. 243 pp.
• Hall, J.S., Medjibe, V., Berlyn, G.P. & Ashton, P.M.S., 2003. Seedling growth of three co-occurring Entandrophragma species (Meliaceae) under simulated light environments: implications for forest management in central Africa. Forest Ecology and Management 179(1/3): 135–144.
• Hawthorne, W. & Jongkind, C., 2006. Woody plants of western African forests: a guide to the forest trees, shrubs and lianes from Senegal to Ghana. Kew Publishing, Royal Botanic Gardens, Kew, United Kingdom. 1023 pp.
• InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/. Accessed May 2007.
• John, T.A. & Onabanjo, A.O., 1990. Gastroprotective effects of an aqueous extract of Entandrophragma utile bark in experimental ethanol-induced peptic ulceration in mice and rats. Journal of Ethnopharmacology 29(1): 87–93.
• Kodym, A., Grzesowiak, E., Partyka, D., Markcinkowski, A. & Kaczynska-Dyba, E., 2002. Technology of eye drops containing aloe (Aloe arborescens Mill.-Liliaceae) and eye drops containing both aloe and neomycin sulphate. Acta Polonial Pharmaceutica 59: 181–186.
• Louppe, D., Deleporte, P., Vigneron, P. & Béhaghel, I., 1999. Projet OIBT PD 10/95 REV. 2 (F). Evaluation des essences indigènes de bois d’œuvre en vue du développement des plantations forestières au Gabon. Rapport final Assistance technique du CIRAD-Forêt, Libreville – Montpellier. 201 pp.
• Makana, J.R., 2004. Fellowship report: How to improve the regeneration of African mahoganies in the northeastern block of the Democratic Republic of Congo. ITTO Tropical Forest Update 14(4): 20–21.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Oteng-Amoako, A.A. (Editor), 2006. 100 tropical African timber trees from Ghana: tree description and wood identification with notes on distribution, ecology, silviculture, ethnobotany and wood uses. 304 pp.
• Parant, B., Boyer, F., Chichignoud, M. & Curie, P., 2008. Présentation graphique des caractères technologiques des principaux bois tropicaux. Tome 1. Bois d’Afrique. Réédition. CIRAD-Fôret, Montpellier, France. 186 pp.
• Siepel, A., Poorter, L. & Hawthorne, W.D., 2004. Ecological profiles of large timber species. In: Poorter, L., Bongers, F., Kouamé, F.N. & Hawthorne, W.D. (Editors). Biodiversity of West African forests. An ecological atlas of woody plant species. CABI Publishing, CAB International, Wallingford, United Kingdom. pp. 391–445.
• Synnott, T.J., 1975. Factors affecting the regeneration and growth of seedlings of Entandrophragma utile (Dawe & Sprague) Sprague. PhD thesis, Makerere University, Kampala, Uganda. 275 pp.
• Tailfer, Y., 1989. La forêt dense d’Afrique centrale. Identification pratique des principaux arbres. Tome 2. CTA, Wageningen, Pays Bas. pp. 465–1271.
• Vivien, J. & Faure, J.J., 1985. Arbres des forêts denses d’Afrique Centrale. Agence de Coopération Culturelle et Technique, Paris, France. 565 pp.
Sources of illustration
• Voorhoeve, A.G., 1979. Liberian high forest trees. A systematic botanical study of the 75 most important or frequent high forest trees, with reference to numerous related species. Agricultural Research Reports 652, 2nd Impression. Centre for Agricultural Publishing and Documentation, Wageningen, Netherlands. 416 pp.
• Wilks, C. & Issembé, Y., 2000. Les arbres de la Guinée Equatoriale: Guide pratique d’identification: région continentale. Projet CUREF, Bata, Guinée Equatoriale. 546 pp.
Author(s)
D.B. Mujuni
P.O. Box 1752, Kampala, Uganda


Editors
D. Louppe
CIRAD, Département Environnements et Sociétés, Cirad es-dir, Campus international de Baillarguet, TA C-DIR / B (Bât. C, Bur. 113), 34398 Montpellier Cedex 5, France
A.A. Oteng-Amoako
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
M. Brink
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
General editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
L.P.A. Oyen
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
J.R. Cobbinah
Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana
Photo editor
G.H. Schmelzer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Mujuni, D.B., 2008. Entandrophragma utile (Dawe & Sprague) Sprague. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.

















































Distribution Map wild


1, base of bole; 2, flowering twig; 3, fruit with one valve removed.
Redrawn and adapted by Iskak Syamsudin



tree habit


tree habit


base of bole


bark


bole


leaf


leaf, opened fruit and seeds


opened fruit


opened fruit and seeds


various parts of the tree
obtained from W.D. Hawthorne



log


wood


wood in transverse section


wood in tangential section


wood in radial section