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Mitragyna ledermannii (K.Krause) Ridsdale

Protologue
Blumea 24(1): 68 (1978).
Family
Rubiaceae
Synonyms
Mitragyna ciliata Aubrév. & Pellegr. (1936), Hallea ciliata (Aubrév. & Pellegr.) J.-F.Leroy (1975), Hallea ledermannii (K.Krause) Verdc. (1985), Fleroya ledermannii (K.Krause) Y.F.Deng (2007).
Origin and geographic distribution
Mitragyna ledermannii occurs from Liberia east to the Central African Republic, and south to Gabon, DR Congo and Cabinda (Angola).
Uses
The wood, often traded as ‘abura’ or ‘bahia’, is used for light construction, flooring, interior joinery, interior trim, furniture, vehicle bodies, mine props, sporting goods, toys, novelties, musical instruments, transmission poles, boxes, crates, canoes, oars, tool handles, food containers, carving, draining boards and particle board. It is also suitable for veneer and plywood. In DR Congo the wood is recommended for paper making.
The bark has several uses in traditional medicine. Bark decoctions and macerations are taken to treat fever, vomiting, general weakness, hypertension, dysentery, gonorrhoea, amenorrhoea, leprosy, colds, chest pain, food poisoning and sterility, to ease childbirth, and as anthelmintic and diuretic. Bark decoctions are added to a bath to treat rheumatism, and bark powder is applied to skin complaints. The bark serves as fish poison. Leaves are occasionally used to treat dysentery and gonorrhoea. They are also used for thatching and wrapping kola nuts.
Production and international trade
The wood of Mytragyna ledermannii is considered a first class wood of general utility. In trade it is not distinguished from Mitragyna stipulosa (DC.) Kuntze wood and together they are sold under the name ‘abura’ or ‘bahia’. In the 1960s the main exporter to Great Britain was Nigeria with about 53,000 m³ of logs and 1300 m³ of sawn wood per year, whereas Equatorial Guinea exported about 3400 m³ per year. Other countries started the trade in Mitragyna wood later. In Gabon the volume of Mitragyna logs exported increased from 10,000 m³ in 1982 to 25,000 m³ in 1991, and to 45,000 m³ in 1999. In 1999 ‘bahia’ ranked as fifth most important timber in Gabon. In 2004 the export of ‘bahia’ sawn wood from Congo was 3000 m³ at an average price of US$ 165/m³; small amounts of veneer were also exported at an average price of US$ 177/m³. In 2005 Côte d’Ivoire exported 14,000 m³ of sawn wood at an average price of US$ 439/m³, and additionally small amounts of plywood.
Properties
The heartwood is pale brown to pinkish brown or greyish brown and indistinctly demarcated from the sapwood. The grain is straight to interlocked, texture fine and even. The wood has an unpleasant odour when freshly cut.
The wood is medium-weight with a density of 520–620 kg/m³ at 12% moisture content. It air and kiln dries rapidly, with slight risk of distortion and checking. The rates of shrinkage are moderately high, from green to oven dry 4.2–4.4% radial and 8.8–10.2% tangential. Once dry, the wood is moderately stable in service.
At 12% moisture content, the modulus of rupture is 73–128 N/mm², modulus of elasticity 7050–8750 N/mm², compression parallel to grain 38–51 N/mm², shear 4.5–9 N/mm², cleavage 13–18 N/mm, Janka side hardness 3500 N, Janka end hardness 5150 N and Chalais-Meudon side hardness 1.1–1.8.
The wood works easily with hand and machine tools, but the blunting effect on saw teeth and cutting edges is often fairly high in dried wood; the use of stellite-tipped saw teeth and tungsten-carbide cutting edges is recommended. The wood is brittle and moderately fissile. The wood surface takes a high polish and finishes well, but cutting edges should be kept sharp. The nailing and screwing properties are good. Gluing is not problematic, but steam bending properties are poor. The wood has good veneering properties. It is not durable, being susceptible to termite, dry-wood borer and marine borer attacks. The sapwood is susceptible to pinhole borers. The sapwood is easy to treat with preservatives, the heartwood moderately easy. Sawdust may be irritant and cases of nausea, eye irritation and dizziness have been recorded.
The wood contains about 43.5% cellulose, 32.7% lignin, 13.8% pentosan, 1.0% ash and 0.16(–0.23)% silica. The solubility is 2.8% in boiling water, 3.4% in alcohol-benzene and 12.9% in a 1% NaOH solution. The wood is suitable for paper production by the kraft process, but the pulp yield is low, about 45%. The tearing strength of the paper is comparatively high.
Bark extracts contain alkaloids, flavonoids and kaempferol derivatives, and showed vasodilating activity in experiments with rats and guinea-pigs. They also showed potent anti-inflammatory and analgesic effects in rats. The alkaloids have been reported to have local anaesthetic activity, to increase heart rhythm and to affect the lymphatic system of the intestines. Leaves and roots also contain alkaloids. Leaf extracts showed in-vitro antiplasmodial activity, also against chloroquine-resistant strains of Plasmodium falciparum.
Description
Evergreen medium-sized to fairly large tree up to 35(–40) m tall; bole straight, cylindrical, branchless for up to 20 m, up to 100(–115) cm in diameter, usually without buttresses but sometimes with low rounded buttresses; bark surface smooth to irregularly thin-scaly or longitudinally fissured, with lenticels in longitudinal lines, greyish brown to yellowish brown, inner bark finely fibrous, yellowish creamy to pinkish creamy, rapidly turning brownish upon exposure; crown fairly small and irregular, with few, heavy, often gnarled branches; twigs angular, nearly glabrous. Leaves opposite, simple; stipules obovate, up to 10(–12) cm × 7 cm, with many parallel veins; petiole up to 5 cm long, grooved above; blade nearly orbicular to obovate, 10–60 cm × 5–30(–45) cm, cuneate to rounded at base, rounded at apex, margins sometimes slightly wavy, leathery, with only scattered hairs on veins, pinnately veined with 5–12 pairs of lateral veins. Inflorescence a head, up to 70-flowered, with numerous bracts between the flowers, heads arranged in terminal cymes; peduncle up to 10 cm long, nearly glabrous. Flowers bisexual, regular, 5(–7)-merous, sessile, scented; calyx c. 3 mm long, with minute lobes hairy at apex; corolla white, tube 1–3.5 mm long, lobes triangular, 1–2 mm long; stamens inserted on corolla tube and alternating with lobes; ovary inferior, c. 2 mm long, 2-celled, style 6–7 mm long, stigma mitre-shaped. Fruit a spindle-shaped capsule 5–8 mm long, many together in globose infructescences 1.5–2.5 cm in diameter, many-seeded. Seeds angular, c. 1.5 mm long, slightly winged. Seedling with epigeal germination; hypocotyl 2–5 mm long, epicotyl 1.5–6 mm long, short-hairy; cotyledons leafy, broadly elliptical, c. 1.5 mm long; first leaves opposite.
Other botanical information
Mitragyna comprises about 10 species, of which 6 in tropical Asia and 4 in tropical Africa. Three of the African species have been placed into a separate genus Hallea (later called Fleroya because Hallea was considered an illegitimate name), but molecular and morphological data support the inclusion in Mitragyna. Mitragyna ledermannii closely resembles Mitragyna stipulosa (DC.) Kuntze, of which the distribution area partly overlaps. In the field, these two species are often indistinguishable, differing mainly in calyx characters. However, there are ecological differences, Mitragyna stipulosa occurring in drier forest zones.
Anatomy
Wood-anatomical description (IAWA hardwood codes):
Growth rings: 2: growth ring boundaries indistinct or absent. Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 25: intervessel pits small (4–7 μm); 29: vestured pits; 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; 48: 20–40 vessels per square millimetre. Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 62: fibres with distinctly bordered pits; (63: fibre pits common in both radial and tangential walls); 66: non-septate fibres present; 69: fibres thin- to thick-walled; (70: fibres very thick-walled). Axial parenchyma: 76: axial parenchyma diffuse; 77: axial parenchyma diffuse-in-aggregates; 78: axial parenchyma scanty paratracheal; 92: four (3–4) cells per parenchyma strand; 93: eight (5–8) cells per parenchyma strand. Rays: 97: ray width 1–3 cells; (102: ray height > 1 mm); 107: body ray cells procumbent with mostly 2–4 rows of upright and/or square marginal cells; 108: body ray cells procumbent with over 4 rows of upright and/or square marginal cells; 115: 4–12 rays per mm. Mineral inclusions: 159: silica bodies present; 160: silica bodies in ray cells.
(F.D. Kamala, P. Baas & H. Beeckman)
Growth and development
Mitragyna ledermannii is fast growing. In agroforestry plantations in Ghana, trees reached 10 m tall 9 years after planting, but a tree of 10 m tall after 6 years has also been reported with a mean annual bole diameter increment of 1 cm. In thinned natural stands in Nigeria, the mean annual diameter increment of boles was 1 cm, with the fastest growing trees reaching 2 cm/year. Trees show monopodial growth in the first 10 years.
Trees produce knee roots that reach a few cm above soil level, later branching to form compound structures in the mud. Flushes of new leaves are bronze-coloured and conspicuous. Flowering of trees has been recorded in Liberia in November–January; fruits ripen about 4 months later. In Côte d’Ivoire trees can apparently be found flowering and fruiting throughout the year, whereas in Nigeria fruiting is recorded twice a year. Trees disperse large amounts of seed by wind, giving rise to dense beds of seedlings (up to 500/m²) on exposed mud.
Ecology
Mitragyna ledermannii occurs in swamps and marshy localities in areas with an annual rainfall above 1250 mm and a temperature of 25–35°C. It needs subsoil moisture during the whole year, but does not grow in swamps that are deeply flooded throughout the year. It is strongly light demanding, and dependent on open swamp sites for regeneration.
Propagation and planting
Mitragyna ledermannii can be propagated by seed and cuttings. Seed is often difficult to collect because it is often already dispersed by wind before the fruits fall. The seeds are very light, with a 1000-seed weight of 0.4 g. Seeds germinate rapidly, under wet and sunny conditions in 1–2 weeks. In shade they may remain dormant for up to 8 months. Under natural conditions, seedling mortality is often high due to competition from other plants and insect attacks. Stem cuttings of about 12 cm long and 2 cm in diameter can be planted in mud beds, which should be kept humid. Under favourable conditions, the development of roots and shoots is rapid and plants can be transplanted into cleared swamp areas at the beginning of the rainy season. Root suckers can also be used for propagation. Young plantations need good care during the first years to counteract too much competition by climbers and other fast-growing plant species.
Management
In Liberia an average density of about 0.25 tree of more than 60 cm in bole diameter per ha has been recorded, in Cameroon about 0.1 tree per ha with an average wood volume of 0.3–1.1 m³/ha. In Gabon an average wood volume of 1.1 m³/ha has been recorded. However, locally Mitragyna ledermannii occurs in high densities. In some localities in Congo, a density of 11 trees with a bole diameter of more than 60 cm has been recorded per ha, with 19 m³ of bole wood per ha.
Harvesting
Boles may have spongy heart and therefore some caution is needed at felling. The minimum bole diameter for harvesting is 50 cm in the Central African Republic and 60 cm in Cameroon.
Handling after harvest
Logs should be converted soon after felling or treated with preservatives to prevent sapwood degradation by fungi and insects. Freshly harvested logs float in water and can be transported by river.
Genetic resources
Mitragyna ledermannii is in general locally common in its specific habitat, but it has been heavily overexploited in many areas within its range, e.g. in Ghana. It is therefore classified as vulnerable in the IUCN Red List of threatened species. However, in 1997 the standing stock in Gabon was estimated to be 7 million m³.
Prospects
Apart from its usefulness as a source of commercially important timber and of traditional medicine, Mitragyna ledermannii has potential for reforestation in swampy areas, where it can play an important role in water management and erosion control. More information is needed on its silvicultural management to draw up regulations for sustainable management, taking into consideration that it often grows in fragile aquatic ecosystems. Several pharmacological properties deserve more research attention for potential drug development, especially the anti-inflammatory, analgesic, antimalarial and antihypertensive activities.
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.
• de Koning, J., 1983. La forêt de Banco. Part 2: La Flore. Mededelingen Landbouwhogeschool Wageningen 83–1. Wageningen, Netherlands. 921 pp.
• 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.
• Keay, R.W.J., 1989. Trees of Nigeria. A revised version of Nigerian trees (1960, 1964) by Keay, R.W.J., Onochie, C.F.A. & Stanfield, D.P. Clarendon Press, Oxford, United Kingdom. 476 pp.
• Phongphaew, P., 2003. The commercial woods of Africa. Linden Publishing, Fresno, California, United States. 206 pp.
• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan. 248 pp.
• Taylor, C.J., 1960. Synecology and silviculture in Ghana. Thomas Nelson and Sons, Edinburgh, United Kingdom. 418 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.
Other references
• Adjétey, T.A.K., Djè, M.K., Vangah-Manda, M., Adoubryn, A.D., Koné, L.P., Koné, M. & Guédé Guina, F., 2007. Antimalarial activity of Mitragyna ciliata (Aubrev. and Pellegr.) (Rubiaceae): Preliminary study. South African Journal of Botany 73(2): 226–229.
• African Regional Workshop (Conservation & Sustainable Management of Trees, Zimbabwe), 1998. Hallea ledermannii. In: IUCN. 2010 IUCN Red list of threatened species. Version 2010.1. [Internet] http://www.iucnredlist.org. Accessed October 2010.
• ATIBT (Association Technique Internationale des Bois Tropicaux), 1986. Tropical timber atlas: Part 1 – Africa. ATIBT, Paris, France. 208 pp.
• Christy, P., Jaffré, R., Ntougou, O. & Wilks, C., 2003. La forêt et la filière bois au Gabon. Projet Aménagement Forestier et Environnement, Libreville, Gabon. 389 pp.
• CIRAD Forestry Department, 2009. Abura. [Internet] Tropix 6.0. http://tropix.cirad.fr/ africa/abura.pdf. Accessed June 2010.
• Dongmo, A., Kamanyi, M.A., Tan, P.V., Bopelet, M., Vierling, W. & Wagner, H., 2004. Vasodilating properties of the stem bark extract of Mitragyna ciliata in rats and guinea pigs. Phytotherapy Research 18(1): 36–39.
• Dongmo, A.B., Kamanyi, A., Dzikouk, G., Nkeh, B.C., Tan, P.V., Nguelefack, T., Nole, T., Bopelet, M. & Wagner, H., 2003. Anti-inflammatory and analgesic properties of the stem bark extract of Mitragyna ciliata (Rubiaceae) Aubrev. & Pellegr. Journal of Ethnopharmacology 84(1): 17–21.
• Gassita, J.N., Nze Ekekang, L., De Vecchy, H., Louis, A.M., Koudogbo, B. & Ekomié, R. (Editors), 1982. Les plantes médicinales du Gabon. CENAREST, IPHAMETRA, mission ethnobotanique de l’ACCT au Gabon, 10–31 juillet 1982. 26 pp.
• Hall, J.B. & Swaine, M.D., 1981. Distribution and ecology of vascular plants in a tropical rain forest: forest vegetation of Ghana. W. Junk Publishers, the Hague, Netherlands. 383 pp.
• Hawthorne, W., 1990. Field guide to the forest trees of Ghana. Natural Resources Institute, for the Overseas Development Administration, London, United Kingdom. 275 pp.
• 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.
• Irvine, F.R., 1961. Woody plants of Ghana, with special reference to their uses. Oxford University Press, London, United Kingdom. 868 pp.
• Iwu, M.M., 1993. Handbook of African medicinal plants. CRC Press, Boca Raton, Florida, United States. 464 pp.
• Liu, K., Eastwood, R.J., Flynn, S., Turner, R.M. & Stuppy, W.H., 2008. Mitragyna ledermannii. [Internet] Seed Information Database Release 7.1, May 2008. http://data.kew.org/sid/. Accessed June 2010.
• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.
• Razafimandimbison, S.G. & Bremer, B., 2002. Phylogeny and classification of Naucleeae s.l. (Rubiaceae) inferred from molecular (ITS, rBCL, and tRNT-F) and morphological data. American Journal of Botany 89: 1027–1041.
• 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.
• UNEP-WCMC, 2006. Contribution to an evaluation of tree species using the new CITES Listing Criteria. UNEP World Conservation Monitoring Centre, Cambridge, United Kingdom. [Internet]. http://www.unep-wcmc.org/ species/tree_study/pdfs/ 1.pdf. Accessed June 2010.
• Vivien, J. & Faure, J.J., 1985. Arbres des forêts denses d’Afrique Centrale. Agence de Coopération Culturelle et Technique, Paris, France. 565 pp.
• White, L. & Abernethy, K., 1997. A guide to the vegetation of the Lopé Reserve, Gabon. 2nd edition. Wildlife Conservation Society, New York, United States. 224 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.
• White, L. & Abernethy, K., 1997. A guide to the vegetation of the Lopé Reserve, Gabon. 2nd edition. Wildlife Conservation Society, New York, United States. 224 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)
Nyunaï Nyemb
Institut de Recherches Médicales et d’Etudes des Plantes Médicinales, B.P. 3805, Yaoundé, Cameroon


Editors
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands
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
Associate editors
E.A. Obeng
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:
Nyemb, Nyunaï, 2011. Mitragyna ledermannii (K.Krause) Ridsdale. In: Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). Prota 7(2): Timbers/Bois d’œuvre 2. [CD-Rom]. PROTA, Wageningen, Netherlands.
Distribution Map wild


1, base of bole; 2, tree habit; 3, part of flowering twig.
Redrawn and adapted by Iskak Syamsudin



Mitragyna ledermannii


Mitragyna ledermannii


Mitragyna ledermannii


Mitragyna ledermannii