Tessmannia lescrauwaetii (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Timber

Tessmannia lescrauwaetii (De Wild.) Harms

Protologue: Engl. & Drude, Veg. Erde 9, III, 1: 457 (1915).

Family: Caesalpiniaceae (Leguminosae - Caesalpinioideae)

Origin and geographic distribution

Tessmannia lescrauwaetii occurs in Cameroon, Central African Republic, Gabon and DR Congo.

Uses

In DR Congo the wood is used for joinery and boxes. It is suitable for heavy construction, heavy flooring, mine props, railway sleepers, ship building, vehicle bodies, sporting goods and turnery. The tree produces a copal resin, which is possibly used locally.

Production and international trade

The wood is only used locally and not traded on the international timber market.

Properties

The heartwood is pinkish brown to dark red, sometimes with irregular darker streaks, and distinctly demarcated from the greyish brown, up to 10 cm wide sapwood. The grain is usually straight, texture fine and even. Wood surfaces show a decorative stripe figure. The wood contains a blackish green resinous exudate. It is heavy, with a density of 880–1000 kg/m³ at 12% moisture content, and hard. It is difficult to dry, and logs should be processed soon after felling to avoid serious checking. The rates of shrinkage are moderate to high. Once dry, the wood is moderately stable to unstable in service. At 12% moisture content, the modulus of rupture is about 185 N/mm², modulus of elasticity 20,900 N/mm², compression parallel to grain 78 N/mm², cleavage 24.5 N/mm and Chalais-Meudon side hardness 8.1.

The wood saws fairly well, but considerable power is needed because of its hardness. However, its silica content is low (0.004%). It works well with both hand and machine tools. The resin in the wood may interfere with finishing and gluing. Pre-boring is needed for nailing. The heartwood is very durable, even in contact with the ground or water, and is resistant to fungal and borer attacks, but the sapwood is susceptible to Lyctus attack. The heartwood is extremely resistant to impregnation with preservatives. The wood contains 0.5% ash.

Description

• Medium-sized tree up to 30 m tall; bole branchless for up to 20 m, straight and cylindrical, up to 80(–130) cm in diameter, without buttresses; bark surface fairly smooth or finely fissured, dark grey to blackish, inner bark moderately thick, pinkish brown; twigs short-hairy, becoming glabrous.
• Leaves alternate, usually imparipinnately compound with 8–18(–20) leaflets; stipules obliquely lanceolate, 1.5–2.5 cm long, caducous or persistent; petiole and rachis together (3.5–)7–15(–25) cm long, channelled above; leaflets usually alternate, oblong to obovate or lanceolate, 1.5–7 cm × 0.5–2.5 cm, asymmetrical at base, indistinctly short-acuminate at apex but tip slightly notched, nearly glabrous, with many translucent dots, pinnately veined with 10–16 pairs of lateral veins.
• Inflorescence an axillary raceme 2.5–9 cm long, short-hairy and with numerous glands.
• Flowers bisexual, slightly zygomorphic; pedicel 0.5–2 cm long; sepals 4, slightly fused at base, ovate-lanceolate, unequal, c. 1.5 cm long, one slightly broader than other 3, short-hairy and with numerous glands outside; petals 5, free, linear-oblong to obovate, 2–3 cm × 0.5–1 cm, one smaller than other 4, pinkish white; stamens 10, 9 fused at base and 1 free, unequal in length, 1.5–2.5 cm long; ovary superior, oblong, 0.5–1 cm long, hairy and with glands, on c. 0.5 cm long stipe, style 2–3 cm long, glabrous.
• Fruit a flattened oblong to ellipsoid or obovoid pod 4.5–6 cm long, reddish brown, short-hairy and with many glandular warts producing a fragrant resin, 2–4-seeded.
• Seeds oblong, c. 1.5 cm × 1 cm, glossy black, with hard seed coat.

Other botanical information

Tessmannia comprises about 15 species and is restricted to tropical Africa, from Guinea and Sierra Leone eastward to Kenya, and southward to Tanzania, Zambia and Angola. Gabon and DR Congo are richest in species, with about 8 and 10, respectively. It is related to Sindora and Sindoropsis, which differ in having only 1 petal and 2 fertile stamens, and 1 petal and 10 fertile stamens, respectively. The wood of several other Tessmannia spp. is used for similar purposes as that of Tessmannia lescrauwaetii.

Tessmannia africana

Tessmannia africana Harms is a medium-sized to large tree up to 50 m tall with bole branchless for up to 30 m and up to 120 cm in diameter, occurring in the same area as Tessmannia lescrauwaetii. Its pinkish brown to reddish brown or dark brown and heavy wood, with a density of 840–1070 kg/m³ at 12% moisture content, is used in DR Congo for carpentry and railway sleepers, and it is suitable for similar purposes as that of Tessmannia lescrauwaetii, and additionally for toys, novelties, agricultural implements and tool handles. Bark decoctions are applied as an enema in traditional medicine as an aphrodisiac. The resin from crushed fruits is used as perfume.

Tessmannia anomala

Tessmannia anomala (Micheli) Harms is a medium-sized to large tree up to 50 m tall with bole branchless for up to 30 m and up to 130 cm in diameter, also occurring in about the same area as Tessmannia lescrauwaetii. In DR Congo its dark brown and hard wood is used for carpentry and railway sleepers.

Tessmannia baikiaeoides

Tessmannia baikiaeoides Hutch. & Dalziel is a small tree up to 10 m tall with bole up to 60 cm in diameter, occurring in upland forest in Sierra Leone, Liberia and western Côte d’Ivoire. Its hard wood is used for posts and tool handles.

Tessmannia dewildemaniana

Tessmannia dewildemaniana Harms is an apparently rare large tree, occurring in Congo, DR Congo and northern Angola. Its brown wood is locally used for furniture.

Tessmannia yangambiensis

Tessmannia yangambiensis Louis ex J.Léonard is a large tree up to 50 m tall with bole branchless up to 30 m and up to 130 cm in diameter with a very limited distribution in DR Congo. Its wood is heavy, with a density of 880–1000 kg/m³ at 12% moisture content, and is suitable for similar purposes as that of Tessmannia lescrauwaetii, and additionally for interior trim, toys, novelties, agricultural implements and tool handles.

Anatomy

Wood-anatomical description (IAWA hardwood codes):

• Growth rings: 1: growth ring boundaries distinct.
• Vessels: 5: wood diffuse-porous; 13: simple perforation plates; 22: intervessel pits alternate; 23: shape of alternate pits polygonal; 26: intervessel pits medium (7–10 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; 43: mean tangential diameter of vessel lumina ≥ 200 μm; 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; 66: non-septate fibres present; 69: fibres thin- to thick-walled; (70: fibres very thick-walled).
• Axial parenchyma: (78: axial parenchyma scanty paratracheal); 79: axial parenchyma vasicentric; (80: axial parenchyma aliform); 83: axial parenchyma confluent; 85: axial parenchyma bands more than three cells wide; 89: axial parenchyma in marginal or in seemingly marginal bands; 91: two cells per parenchyma strand; 92: four (3–4) cells per parenchyma strand.
• Rays: 98: larger rays commonly 4- to 10-seriate; 104: all ray cells procumbent; 115: 4–12 rays per mm.
• Secretory elements and cambial variants: 127: axial canals in long tangential lines.
• Mineral inclusions: 136: prismatic crystals present; 142: prismatic crystals in chambered axial parenchyma cells.

(E.K. Achi, S. N’Danikou, H. Beeckman & P.E. Gasson)

Growth and development

In Gabon flowering Tessmannia lescrauwaetii trees have been recorded in December.

Ecology

Tessmannia lescrauwaetii occurs in lowland rainforest up to 500 m altitude, usually in primary forest.

Management

Tessmannia lescrauwaetii occurs scattered and in low densities in the forest, and this seems in general also to be the case for other Tessmannia spp., although some of them may be locally abundant.

Harvesting

The hard and dense wood makes logging of trees quite difficult with ordinary tools, whereas the resin present in the wood may cause additional difficulties by gumming-up saw teeth.

Handling after harvest

The logs are too heavy to be transported by river.

Genetic resources

Tessmannia lescrauwaetii has a fairly large area of distribution, but occurs scattered and mainly in undisturbed forest, which makes it liable to genetic erosion in areas with large-scale logging activities.

Prospects

Although the wood of Tessmannia lescrauwaetii and other Tessmannia spp. is difficult to dry and contains resin, it is decorative and has an excellent natural durability, which makes it useful for local construction including hydraulic works and promising as export timber for purposes where durability is required. However, amounts of timber available seem to be limited as trees usually occur scattered in low densities. Information on growth rates, regeneration and ecological requirements is needed to judge the prospects of Tessmannia lescrauwaetii and other Tessmannia spp. as timber trees of more commercial importance on a sustainable basis. For the time being, these seem rather poor. A taxonomic revision of the poorly known genus Tessmannia is needed.

Major references

• Aubréville, A., 1970. Légumineuses - Césalpinioidées (Leguminosae - Caesalpinioideae). Flore du Cameroun. Volume 9. Muséum National d’Histoire Naturelle, Paris, France. 339 pp.

• 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., 1995. The useful plants of West Tropical Africa. 2nd Edition. Volume 3, Families J–L. Royal Botanic Gardens, Kew, Richmond, United Kingdom. 857 pp.

• Maisonneuve, J.F. & Manfredini, M.L. (Editors), 1988. Wamba. Les bois du Gabon. Département de Sciences Naturelles, Institut Pédagogique National, Ministère de l’éducation nationale, Libreville, Gabon. pp. 64–65.

• 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.

• Tailfer, Y., 1989. La forêt dense d’Afrique centrale. Identification pratique des principaux arbres. Tome 2. CTA, Wageningen, Pays-Bas. pp. 465–1271.

• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan. 248 pp.

• Wilczek, R., Léonard, J., Hauman, L., Hoyle, A.C., Steyaert, R., Gilbert, G. & Boutique, R., 1952. Caesalpiniaceae. In: Robyns, W., Staner, P., Demaret, F., Germain, R., Gilbert, G., Hauman, L., Homès, M., Jurion, F., Lebrun, J., Vanden Abeele, M. & Boutique, R. (Editors). Flore du Congo belge et du Ruanda-Urundi. Spermatophytes. Volume 3. Institut National pour l’Étude Agronomique du Congo belge, Brussels, Belgium. pp. 234–554.

Other references

• Aké Assi, L., Abeye, J., Guinko, S., Riguet, R. & Bangavou, X., 1985. Médecine traditionnelle et pharmacopée - Contribution aux études ethnobotaniques et floristiques en République Centrafricaine. Agence de Coopération Culturelle et Technique, Paris, France. 140 pp.

• 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.

• Fouarge, J., Gérard, G. & Sacré, E., 1953. Bois du Congo. Institut National pour l’Etude Agronomique du Congo belge (INEAC), Brussels, Belgium. 424 pp.

• Fouarge, J., Quoilin, J. & Roosen, P., 1970. Essais physiques, mécaniques et de durabilité de bois de la République Démocratique du Congo. Série technique No 76. Institut National pour l’Etude Agronomique du Congo (INEAC), Brussels, Belgium. 40 pp.

• Fouarge, J., Sacré, E. & Mottet, A., 1950. Appropriation des bois congolais aux besoins de la métropole. Série Technique No 38. Institut National pour l’Étude Agronomique du Congo belge (INEAC), Brussels, Belgium. 17 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.

• Neuwinger, H.D., 2000. African traditional medicine: a dictionary of plant use and applications. Medpharm Scientific, Stuttgart, Germany. 589 pp.

• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.

• Torelli, N., Piškur, M. & Tišler, V., 2003. Wood species of the Central African Republic: ash and silica content. Zbornik Gozdarstva in Lesarstva 72: 53–61.

• 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

• Léonard, J., 1950. Etude botanique des copaliers du Congo belge. INEAC, série scientifique no 45. Bruxelles, Belgium. 158 pp.

• Tailfer, Y., 1989. La forêt dense d’Afrique centrale. Identification pratique des principaux arbres. Tome 2. CTA, Wageningen, Pays-Bas. pp. 465–1271.

Author(s)

• R.H.M.J. Lemmens, PROTA Network Office Europe, Wageningen University, P.O. Box 341, 6700 AH Wageningen, Netherlands

Correct citation of this article

Lemmens, R.H.M.J., 2012. Tessmannia lescrauwaetii (De Wild.) Harms. In: Lemmens, R.H.M.J., Louppe, D. & Oteng-Amoako, A.A. (Editors). PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Accessed 1 April 2025.

• See the Prota4U database.