PROTA homepage Prota 7(1): Timbers/Bois d’œuvre 1
Record display


Baillonella toxisperma Pierre

Protologue
Not. bot. 1: 14 (1890).
Family
Sapotaceae
Chromosome number
2n = 24
Synonyms
Mimusops djave Engl. (1897).
Vernacular names
Moabi, African pearwood (En). Moabi (Fr). Muabi (Po).
Origin and geographic distribution
Moabi occurs from southern Nigeria to Gabon, Congo and south-western DR Congo.
Uses
Moabi wood is used for joinery and carpentry in exterior applications, e.g. for doors, windows, garden furniture and marine construction. Its uniform reddish brown colour and fine grain make it popular for veneer, furniture, decorative uses and flooring.
The fruit pulp is eaten fresh although it contains latex. The seed kernel contains a fatty oil that is used in cooking, for cosmetic purposes and in traditional medicine. The oil is applied as a pomade to the hair and used in soap manufacture, and it is applied externally to treat rheumatic pains. The residues of oil extraction are sometimes used as fish poison. Bark decoctions are used to treat kidney problems, toothache, rachitis, vaginal infections and affections of the respiratory and digestive tracts. The tree has several ritual uses.
Production and international trade
Commercial exploitation of moabi started in the mid 1960s. In 1960 the total trade of logs amounted to 3000 m³, in 1973 already to 47,300 m³ and additionally almost 1000 m³ of processed wood. In 2003 Cameroon exported 16,000 m³ processed wood and Gabon 54,000 m³ logs.
Moabi bark is regularly sold in markets in Cameroon for medicinal purposes; in 2000 the amount traded was estimated at 3.2 t. The seed oil is sold on local markets, but no statistics are available.
Properties
Heartwood pinkish brown to reddish brown, fairly distinctly demarcated from the pinkish white or greyish brown sapwood. The grain is straight to slightly interlocked, texture fine. Wood with satiny lustre on quarter-sawn surfaces. Growth rings more or less distinct.
The density is 820–940 kg/m³ at 12% moisture content. The timber dries slowly, but with care it seasons without checking and warping. The shrinkage rates are moderate, from green to oven dry 5.8–6.5% radial and 6.9–8.6% tangential. Slow drying to a moisture content of 10–12% is needed for use in joinery or carpentry. Once dry, the wood is stable.
At 12% moisture content, the modulus of rupture is 148–218 N/mm², modulus of elasticity 15,100 N/mm², compression parallel to grain 57–84 N/mm², cleavage 18–24 N/mm and Chalais-Meudon side hardness 5.6–7.0.
The wood is difficult to work due to the presence of silica (0.2–0.3%) and because it is hard. Stellite-tipped sawteeth are needed. The wood glues, nails and finishes well, and has good steam-bending properties. Painting and varnishing with the principal industrial products do not cause problems. After steaming for 48–60 hours, rotary peeling and slicing give veneer and plywood of satisfactory quality.
Moabi wood is durable. It is resistant to fungi, Lyctus beetles and termites. It is fairly resistant to marine borers. Impregnation by preservatives is difficult or impossible.
The allelopathic compound 3-hydroxyuridine has been isolated from leaves, stems and roots of moabi; it inhibited the growth of seedlings of some test plants.
Adulterations and substitutes
Moabi wood can be confused with that of other Sapotaceae species having heavy and reddish brown wood, particularly mukulungu (Autranella congolensis (De Wild.) A.Chev.), makore (Tieghemella heckelii (A.Chev.) Roberty) and douka (Tieghemella africana Pierre). The fatty seed oil is similar to that of Tieghemella and shea butter tree (Vitellaria paradoxa C.F.Gaertn.) and used for similar purposes.
Description
Very large tree up to 60(–70) m tall; bole up to 300(–500) cm in diameter, straight and cylindrical, sometimes swollen in lower part, reaching up to 30 m to the first branches, without buttresses; bark 4–5 cm thick, surface red-brown to dark grey, deeply longitudinally furrowed, red-brown in outer part of section, yellow-pink in inner part, little fibrous, exuding a sticky latex; crown umbrella-shaped, very large, up to 50 m in diameter, heavy branches spreading and sinuate; ultimate branches very thick, with numerous scars of fallen leaves. Leaves arranged spirally in tufts at the ends of branches, simple; stipules lanceolate, large, persistent; petiole 3–4 cm long, slender; blade narrowly obovate, 15–30 cm × 5–10 cm, cuneate at base, shortly acuminate at apex, margin entire, initially reddish hairy below but glabrescent, lateral veins numerous, distinct, curving and joined near leaf margin. Flowers in dense fascicles at the ends of branches, bisexual, regular; pedicel 2–3 cm long, pubescent; calyx with 2 whorls of 4 lobes c. 1 cm long, pubescent outside; corolla with c. 2.5 mm long tube and 8 lobes c. 4 mm long, each lobe with 2 large lateral segments c. 5.5 mm long, creamy white; stamens 8, inserted on the corolla tube in front of the corolla lobes, free, filaments short, 8 larger staminodes alternating with the stamens; ovary superior, long-hairy, 8-celled, each cell with 1 ovule, style short. Fruit a large, globose, smooth berry 5–8 cm in diameter, grey-green, becoming greenish yellow when ripe, containing 1–2(–3) seeds in a pale yellowish pulp. Seeds ellipsoid, slightly laterally compressed, c. 4 cm long, testa thin, smooth and shining in dorsal part, rough and bullate in ventral part (scar); endosperm thin or absent. Seedling with epigeal germination, hypocotyl short, 0.5–1.5 cm long, epicotyl 15–26 cm long, reddish to greyish brown hairy, cotyledons thick, sessile, c. 4 cm × 1 cm, green.
Other botanical information
Baillonella comprises a single species and resembles Tieghemella and Mimusops, the first differing in the absence of stipules and its thicker seed coat, the latter in its seed with small and basal scar.
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; (7: vessels in diagonal and/or radial pattern); (10: vessels in radial multiples of 4 or more common); 13: simple perforation plates; 22: intervessel pits alternate; (23: shape of alternate pits polygonal); 26: intervessel pits medium ( 7–10 μm); 27: intervessel pits large ( 10 μm); 30: vessel-ray pits with distinct borders; similar to intervessel pits in size and shape throughout the ray cell; 31: vessel-ray pits with much reduced borders to apparently simple: pits rounded or angular; 32: vessel-ray pits with much reduced borders to apparently simple: pits horizontal (scalariform, gash-like) to vertical (palisade); 33: vessel-ray pits of two distinct sizes or types in the same ray cell; 42: mean tangential diameter of vessel lumina 100–200 μm; 47: 5–20 vessels per square millimetre; 56: tyloses common. Tracheids and fibres: 61: fibres with simple to minutely bordered pits; 66: non-septate fibres present; 69: fibres thin- to thick-walled. Axial parenchyma: (77: axial parenchyma diffuse-in-aggregates); 86: axial parenchyma in narrow bands or lines up to three cells wide; 87: axial parenchyma reticulate; 93: eight (5–8) cells per parenchyma strand; (94: over eight cells per parenchyma strand). Rays: 97: ray width 1–3 cells; (100: rays with multiseriate portion(s) as wide as uniseriate portions); 106: body ray cells procumbent with one row of upright and/or square marginal cells; 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; (161: silica bodies in axial parenchyma cells).
(P. Détienne & E.A. Wheeler)
Growth and development
Germination takes 1–4 weeks. Shade is required for germination, and seeds germinate in abundance under or close to mother trees. However, young plants of 1 m tall are rare as a result of predation by animals, mainly elephants, and the survival rate of moabi seedlings after 18 months is practically nil under the mother tree and very low (less than 2%) elsewhere. In forest undergrowth seedlings grow 4–5 cm/year. They respond rapidly to opening of the forest cover and direct sunlight, and under these circumstances may grow up to 40 cm/year. In natural forest, moabi trees of 10 cm in stem diameter have an average annual diameter growth of 1 mm. When the tree bole has attained 1 m in diameter and the crowns have reached or passed the forest canopy, diameter growth is up to 9.5 mm/year. It has been estimated from growth rings and C14 dating that a tree with a bole diameter of 1 m was 260 years old and one with a diameter of 2.8 m 600–700 years. In an 11-year-old plantation in Ekouk (Gabon) trees grown in full sun showed a mean annual height growth of 130 cm and under partial shade 165 cm. A dense (570 stems/ha) plantation of 67 years old near Libreville had a mean annual diameter increment of 3.5 mm, with the most vigorous tree reaching 9 mm; the annual volume increment was estimated at 4.2 m³/ha, with an average clear bole of 15 m and 23% of the trees having a straight and cylindrical bole.
The tree starts flowering at an age of 50–70 years, when it has reached the light in the upper storey of the forest, but regular fructification starts still later, when the bole has reached 70 cm in diameter. Fruits are produced annually, but mass production occurs once in 3 years. About 6000 seeds per tree are produced within a cycle of 3 years; a single tree produced 2460 kg of fruits, including 327 kg of seed kernels.
In Cameroon flowering starts at the end of the long dry season and beginning of the short rainy season, in February to April. It is accompanied by complete defoliation of the tree; when the tree does not flower, it maintains part of its foliage. Fruits ripen just before the start of the long rainy season, from June to August. The fruiting season lasts up to 4 weeks for an individual tree, but may last 3 months for the whole population. In Gabon moabi fruits become ripe from December to February. Elephants are the main seed dispersers. They eat the fruits, and intact seeds can be found in the droppings. It is not necessary for the seeds to pass through the intestines for germination, but it does accelerate germination slightly. Other fruit-eating mammals such as giant pouched rats (Cricetomys emini) and monkeys may also disperse seeds, as well as man.
Ecology
Moabi occurs in primary rain forest in humid and warm climates, with a mean annual temperature of 23–26°C and mean annual rainfall of 1500–3000 mm. It usually occurs scattered, with about 1 adult tree per 20 ha, but occasionally loose groups of 5–50 trees are found. Some forests are rich in moabi trees, e.g. Dja forest in Cameroon, with on average 0.6 tree over 70 cm in bole diameter per ha. In Dja forest there is a maximum number of trees in the diameter class 10–40 cm and a secondary maximum at 160–190 cm. At the northern limits of the primary Congolean rain forest in Cameroon large moabi trees are abundant, but regeneration is absent. Moabi can be found on all soil types except on marshy soil.
Propagation and planting
The germination capacity of fresh seeds is high (> 85%), but drops rapidly to 5% after 6 weeks of storage due to rapid degradation of the fatty acids. However, fresh seeds stored at 4°C and humid conditions still showed a germination rate of about 50% after 11 months.
In the nursery the lower half of the seed is buried, with the scar pointing downwards. The mortality of seedlings in the nursery is very low. Partial shading is favourable for seedling development. Under optimal nursery conditions seedlings may reach 35 cm in height after 6 weeks, 45 cm after 3 months and 1.5 m after 18 months. The seedling develops a taproot and it is recommended to sow into polythene pots. At the beginning of the short rainy season in Cameroon 4–5-month-old seedlings are planted into the field under the light shade of about 10 retained adult trees per ha. The shade should be removed gradually when a reduction in diameter growth is observed.
Management
At present, the only management measure for natural forest is the maintenance of a minimum diameter limit for exploitation, i.e. 70 cm in Gabon, 80 cm in Congo and 100 cm in Cameroon. The Pygmy people highly value large moabi trees for their fruits and conflicts arose in Cameroon between the Pygmies and companies entitled by the government to exploit the forest for timber. This has resulted in a law endowing the village chief with the power to authorize the cutting of a moabi tree within 5 km distance from a village.
Diseases and pests
The sapwood is susceptible to attack by insects and fungi. In felled logs some of the insects affecting the sapwood (e.g. Platypes and Scolytes spp.) may reach the heartwood.
Fruits still attached to the tree are attacked by larvae of the beetle Carpophilus sp. and the moth Mussidia sp. When they reach the embryo, the seed will not germinate; otherwise the development of the seedling may be strongly retarded. Bush pigs and porcupines eat the seeds, and bush pigs and antelopes destroy seedlings while eating the fleshy cotyledons and young shoots.
Harvesting
In Cameroon commercial exploitation of moabi implies the cutting of 90% of trees above 100 cm in diameter, leaving only poorly shaped trees. It has been estimated that after 300 years 84% of the harvested volume is re-established and after 500 years 92%. Sustainable production of moabi in natural forest is therefore not possible. Cutting cycles of 30 years, as often practised, threaten moabi populations seriously.
In Cameroon fruit collection starts in July or August. Pygmy families move to localities where clusters of trees are found and stay there for 2–8 weeks. Locally in Gabon people move into temporary camps in January to February, when the moabi trees are fruiting. The collected fruits are depulped and the seed kernels dried. After heating the oil is gathered by pressing with a traditional wooden press. The oil is used domestically or sold. It can be stored for 1–2 years.
Yield
The commercial wood volume of individual trees is about 3 m³ in trees with a bole diameter of 50 cm to about 26 m³ in trees with a bole diameter of 1.8 m.
In 1992, which was a very good year for fruit production, the yield of oil was estimated at 135–165 l per adult tree, which was equivalent to US$ 165–200. The price on markets in Yaoundé and Douala (Cameroon) is more than US$ 3 per l because demand exceeds supply.
Handling after harvest
The sawdust may cause irritation to throat, nose and eyes, and also dermatitis.
Genetic resources
According to the IUCN classification, moabi is vulnerable because of overexploitation and habitat degradation. The low growth rate and often poor natural regeneration make it even more liable to genetic erosion or even extinction in forest liable to timber exploitation.
Prospects
Proper propagation and planting techniques have been developed for moabi and consequently it is possible to include the species in plantation forestry. Although the growth of planted trees can be faster than in natural forest, timber exploitation can not be expected within a century. Moabi trees are important for local populations because of their valuable fruit, and those close to villages should be protected, taking into account that they start fruiting many decades after germination. Moabi deserves protection also because it is the largest and perhaps most impressive tree of the African forest,
Major references
• Aubréville, A., 1964. Sapotacées. Flore du Cameroun. Volume 2. Muséum National d’Histoire Naturelle, Paris, France. 143 pp.
• Burkill, H.M., 2000. The useful plants of West Tropical Africa. 2nd Edition. Volume 5, Families S–Z, Addenda. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 686 pp.
• CTFT (Centre Technique Forestier Tropical), 1956. Moabi. Bois et Forêts des Tropiques 45: 27–30.
• CTFT (Centre Technique Forestier Tropical), 1976. Moabi. Bois et Forêts des Tropiques 169: 37–49.
• Chudnoff, M., 1980. Tropical timbers of the world. USDA Forest Service, Agricultural Handbook No 607, Washington D.C., United States. 826 pp.
• Debroux, L., 1998. L’aménagement des forêts tropicales fondé sur la gestion des populations d’arbres: l’exemple du moabi (Baillonella toxisperma Pierre) dans la forêt du Dja, Cameroun. Thèse de doctorat, Faculté des sciences agronomiques de Gembloux, Belgique. 283 pp.
• Debroux, L., Delvingi, W., Mbolo, M. & Amougou, A., 1998. Régénération du moabi et du mukulungu au Cameroun, perspectives pour l’aménagement. Bois et Forêts des Tropiques 225(1): 1–17.
• Mapaga, D., Ingueza, D. & Louppe, D., 2002. Moabi. CIRAD, Département forestier, Montpellier, France. 4 pp.
• Richter, H.G. & Dallwitz, M.J., 2000. Commercial timbers: descriptions, illustrations, identification, and information retrieval. [Internet]. Version 18th October 2002. http://delta-intkey.com/wood/index.htm. Accessed November 2004.
• Schneemann, J., 1995. Exploitation of moabi in the humid dense forests of Cameroon. Harmonization and improvement of two conflicting ways of exploitation of the same forest resource. BOS Nieuwsletter 14(2): 20–32.
Other references
• Agom, D. & Ogar, D., 1994. Report of study on timber extraction in the Ikobi concession area in Afi river forest reserve. Working Paper Cross River State Forestry Project No 3. 15 pp.
• ATIBT (Association Technique Internationale des Bois Tropicaux), 1986. Tropical timber atlas: Part 1 – Africa. ATIBT, Paris, France. 208 pp.
• Aubréville, A., 1961. Sapotacées. Flore du Gabon. Volume 1. Muséum National d’Histoire Naturelle, Paris, France. 162 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.
• Bierna, V., 1963. Description anatomique des principaux bois tropicaux utilisés en Belgique. Annales Gembloux 69: 425–489.
• Bokdam, J., 1977. Seedling morphology of some African Sapotaceae and its taxonomical significance. Mededelingen Landbouwhogeschool Wageningen 77–20. Wageningen, Netherlands. 84 pp.
• Brown, W.H., 1977. Comparative studies of lesser-known timbers. 6. Marine borer resistance of some African timbers. Woodworking Industry 34(12): 21–22.
• Fouquet, D., 1984. Etude comparative de bois commerciaux provenant de continents différents pouvant être confondus. Bois et Forêts des Tropiques 205: 35–59.
• Ilic, J., 1991. CSIRO atlas of hardwoods. Crawford House Press, Bathurst & CSIRO, Melbourne, Australia and Springer-Verlag, Berlin, Germany. 525 pp.
• InsideWood, undated. [Internet] http://insidewood.lib.ncsu.edu/search/. Accessed May 2007.
• Koumba Zaou, P., Mapaga, D., Nze Nguema, S. & Deleporte, P., 1998. Croissance de 13 essences de bois d’oeuvre plantées en forêt Gabonaise. Bois et Forêts des Tropiques 256(2): 21–32.
• Mollet, M., Tiki-Manga, T., Kengué, J. & Tchoundjeu, Z., 1995. The ‘top 10’ species in Cameroon; a survey of farmers’ views on trees. Agroforestry Today 7(3–4): 14–16.
• Moss, R., 1995. Underexploited tree crops: components of productive and more sustainable farming systems. Journal for Farming Systems Research Extension 5(1): 107–117.
• Normand, D. & Paquis, J., 1976. Manuel d’identification des bois commerciaux. Tome 2. Afrique guinéo-congolaise. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 335 pp.
• Ohigashi, H., Kaji, M., Sakaki, M. & Koshimizu, K., 1989. 3-Hydroxyuridine, an allelopathic factor of an African tree, Baillonella toxisperma. Phytochemistry 28(5): 1365–1368.
• 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.
• Vivien, J. & Faure, J.J., 1988. Fruitiers sauvages du Cameroun. Fruits Paris 44(5): 281–288.
• 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.
Sources of illustration
• Aubréville, A., 1961. Sapotacées. Flore du Gabon. Volume 1. Muséum National d’Histoire Naturelle, Paris, France. 162 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.
Author(s)
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


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
E. Boer
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article:
Louppe, D., 2005. Baillonella toxisperma Pierre. 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, tree habit; 2, flowering branch; 3, fruit; 4, seed.
Redrawn and adapted by Iskak Syamsudin



plantation of 67 years


bole


leafy branches


fruits


log


wood (tangential surface)


wood (radial surface)


wood in transverse section


wood in radial section


wood in tangential section