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Librevillea klainei (Pierre ex Harms) Hoyle

Protologue
Bol. Soc. Brot., sér. 2, 29: 18 (1955).
Family
Caesalpiniaceae (Leguminosae - Caesalpinioideae)
Synonyms
Brachystegia klainei Pierre ex Harms (1907).
Origin and geographic distribution
Librevillea klainei occurs from southern Cameroon, through Equatorial Guinea and Gabon, south to Cabinda (Angola).
Uses
The wood, known as ‘ngaba’ in Gabon, is suitable for heavy construction and flooring.
Properties
The heartwood is yellowish brown to reddish brown with darker streaks and indistinctly demarcated from the sapwood. The texture is moderately coarse. The wood is heavy, with a density of 1040–1130 kg/m³ at 12% moisture content, and very hard. The rates of shrinkage upon air drying are high, from green to oven dry 6.2–7.5% radial and 9.5–11.3% tangential. At 12% moisture content, the modulus of rupture is 225–246 N/mm², modulus of elasticity 17,750–20,700 N/mm², compression parallel to grain 84–94 N/mm², shear 12–19.5 N/mm², cleavage 16.5–31 N/mm and Chalais-Meudon side hardness 11.4–14.7. The wood is fairly resistant to splitting.
Botany
Medium-sized to large tree up to 50 m tall; bole usually straight and cylindrical, up to 110 cm in diameter, with rather thin buttresses up to 2 m high; bark surface rough, slightly peeling with small scales to shallowly fissured, yellowish grey to reddish brown, inner bark fairly thick, fibrous, yellowish brown to greyish brown; twigs short-hairy to glabrous. Leaves alternate, imparipinnately compound with 3–6 leaflets; stipules small, caducous; petiole and rachis together 3–8 cm long; petiolules 3–4 mm long; leaflets alternate, ovate-oblong to lanceolate, 5–10 cm × 2–3 cm, slightly asymmetrical, acuminate at apex, leathery, glabrous, pinnately veined with 6–10 pairs of indistinct lateral veins. Inflorescence a terminal lax panicle with branches 3–5 cm long, short-hairy. Flowers bisexual, whitish, with 2 rounded bracteoles up to 3.5 mm long at base; pedicel 5–10 mm long; tepals (1–)2, c. 2 mm long; stamens 10, slightly fused at base, c. 5 mm long; ovary superior, with short stipe, hairy, 1-celled, style c. 3 mm long. Fruit an oblong to narrowly obovate, flattened pod 7–12 cm × c. 5 cm, with stipe, with faint diagonal veins, dehiscent with 2 woody, spiralling valves, up to 3-seeded.
Librevillea comprises a single species. It is classified in the tribe Macrolobieae, in which its position is still unresolved.
Ecology
Librevillea klainei occurs in lowland rainforest, where it is usually found scattered. It seems to be most abundant on sandy soils in swampy areas.
Management
Seedlings may be quite abundant in the forest. The average wood volume in Gabon has been estimated at 0.65 m³/ha.
Genetic resources and breeding
Although Librevillea klainei is not very widely distributed, with the majority of trees in Gabon, and is restricted to mature rainforest, it does not seem to be threatened by genetic erosion at present.
Prospects
Too little is known about Librevillea klainei to make a fair judgement on its prospects as a timber tree of commercial importance. It probably has low growth rates resulting in hard and heavy wood, which seem to be a serious drawback for sustainable commercial exploitation.
Major references
• Aubréville, A., 1968. Légumineuses - Caesalpinioidées (Leguminosae - Caesalpinioideae). Flore du Gabon. Volume 15. Muséum National d’Histoire Naturelle, Paris, France. 362 pp.
• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 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., 1985. Arbres des forêts denses d’Afrique Centrale. Agence de Coopération Culturelle et Technique, Paris, France. 565 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.
Other references
• Lewis, G., Schrire, B., MacKinder, B. & Lock, M., 2005. Legumes of the world. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 577 pp.
• Newbery, D.M., Gartlan, J.S., Mckey, D.B. & Waterman, P.G., 1986. The influence of drainage and soil phosphorus on the vegetation of Douala-Edea forest reserve Cameroon. Vegetatio 65(3): 149–162.
• 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.
• Sallenave, P., 1971. Propriétés physiques et mecaniques des bois tropicaux. Deuxième supplément. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 128 pp.
Author(s)
R.H.M.J. Lemmens
PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands


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:
Lemmens, R.H.M.J., 2010. Librevillea klainei (Pierre ex Harms) Hoyle. 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.
Librevillea klainei