Prota 7(1): Timbers/Bois d’œuvre 1
Penerb. Madj. Ilmu Peng. Indon. 1: 71 (1959).
Sterculiaceae (APG: Malvaceae)
Tarrietia utilis (Sprague) Sprague var. densiflora Pellegr. (1941), Tarrietia densiflora (Pellegr.) Aubrév. & Normand (1958).
Origin and geographic distribution
Heritiera densiflora is endemic to the north-western part of Gabon.
The wood is recommended for joinery, carpentry, moulding and sliced veneer, and is also useful for exterior and marine applications.
Production and international trade
In the period 1966–1970 Gabon exported about 3000 m³ of round logs of Heritiera densiflora annually. The export increased to on average 8000 m³/year in the period 1999–2003. Heritiera densiflora is traded in mixed consignments of medium-weight hardwood, and is often sold on the timber market mixed with Heritiera utilis (Sprague) Sprague (niangon) from West Africa.
The heartwood is pinkish brown to reddish brown or coppery brown and clearly demarcated from the whitish sapwood. The grain is slightly interlocked, texture moderately coarse. The wood is oily to the touch. The density is 630–840 kg/m³ at 12% moisture content. The wood of Heritiera densiflora dries more slowly than that of Heritiera utilis, often with a tendency to twist. The shrinkage rates are moderate to high: from green to oven dry 3.6–6.6% radial and 7.8–12.7% tangential. At 12% moisture content, the modulus of rupture is 126–188 N/mm², modulus of elasticity 10,700–14,000 N/mm², compression parallel to grain 44–72 N/mm², shear 7–9 N/mm², cleavage 13–24 N/mm and Chalais-Meudon side hardness 3.2–6.0.
Medium-sized to fairly large tree up to 30 m tall; bole up to 60(–100) cm in diameter, with large buttresses; bark pale grey to brown, fissured; young twigs brown pubescent. Leaves alternate, simple or digitately lobed; stipules 0.5–1 cm long, early caducous; petiole 3–45 cm long; blade 10–45 cm × 5–30 cm in outline, elliptical when simple or with 2–7 lobes, obtuse at base, acuminate at apex, densely but not contiguously scaly hairy below, pinnately veined with 10–20 pairs of lateral veins. Inflorescence an axillary, narrow panicle up to 11 cm long, reddish brown pubescent; bracts 0.5–1 cm long, caducous. Flowers unisexual, regular, 4–5-merous, whitish, c. 0.5 cm long; pedicel slender, 0.5–1 cm long; calyx campanulate with lobes about as long as tube, stellately hairy; petals absent; disk annular; male flowers with stamens fused into a column; female flowers with 3–5 carpels united loosely. Fruit consisting of 1–5 woody nuts c. 3 cm × 2 cm with a large wing c. 7.5 cm × 3 cm.
Heritiera comprises about 35 species, the majority of which occur in tropical Asia and 3 species in Africa. Heritiera densiflora is closely related to Heritiera utilis (Sprague) Sprague (niangon) from West Africa. The two species should be carefully compared as they are very similar with most of the recorded differences obscure, e.g. density of indumentum and length of inflorescences. Both species often have simple leaves, but Heritiera densiflora may also have digitately lobed leaves (with lobes distinctly fused at base) and Heritiera utilis may have digitately compound leaves (with leaflets completely free).
Heritiera densiflora occurs in lowland rainforest, often in swampy localities and on sandy-loamy soils.
Genetic resources and breeding
Heritiera densiflora has a very limited distribution area and is probably uncommon there, which makes it easily liable to genetic erosion.
Although Heritiera densiflora is exploited for its timber, which is traded on the international market, very little is known about it. Research is needed to prove that it is truly distinct from Heritiera utilis in botanical characteristics or wood properties.
• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.
• Eyma, F., Méausoone, P.-J. & Martin, P., 2004. Study of the properties of thirteen tropical wood species to improve the prediction of cutting forces in mode B. Annals of Forest Science 61(1): 55–64.
• Hallé, N., 1961. Sterculiacées. Flore du Gabon. Volume 2. Muséum National d’Histoire Naturelle, Paris, France. 150 pp.
• Raponda-Walker, A. & Sillans, R., 1961. Les plantes utiles du Gabon. Paul Lechevalier, Paris, France. 614 pp.
• Savard, J. & Caumartin, L., 1970. Action du fer sur Tarrietia utilis et Tarrietia densiflora. Bois et Forêts des Tropiques 130: 55–64.
• Takahashi, A., 1978. Compilation of data on the mechanical properties of foreign woods (part 3) Africa. Shimane University, Matsue, Japan, 248 pp.
Correct citation of this article:
Lemmens, R.H.M.J., 2005. Heritiera densiflora (Pellegr.) Kosterm. In: Louppe, D., Oteng-Amoako, A.A. & Brink, M. (Editors). Prota 7(1): Timbers/Bois d’œuvre 1. [CD-Rom]. PROTA, Wageningen, Netherlands.