Bikinia durandii (PROTA)

Plant Resources of Tropical Africa Introduction

List of species

General importance
Geographic coverage Africa
Geographic coverage World
Timber
Conservation status

distribution in Africa (wild)

1, base of bole; 2, flowering twig; 3, fruit valve. Redrawn and adapted by Iskak Syamsudin

tree in habitat

tree

Bikinia durandii (F.Hallé & Normand) Wieringa

Protologue: Wageningen Agric. Univ. Pap. 99(4): 207 (1999).

Family: Caesalpiniaceae (Leguminosae - Caesalpinioideae)

Synonyms

• Monopetalanthus durandii F.Hallé & Normand (1960).

Vernacular names

• Andoung de Durand (Fr).

Origin and geographic distribution

Bikinia durandii has a small area of distribution, being endemic to Gabon.

Uses

The wood, traded from Gabon as ‘andoung’ together with other Bikinia spp., Aphanocalyx spp. and some other Caesalpiniaceae, is used for light construction, joinery, furniture, vehicle bodies, ladders, sporting goods, toys, novelties, tool handles, boxes, crates, matches, veneer, plywood and pulpwood. It is also suitable for light flooring, interior trim, ship building and railway sleepers.

Production and international trade

The export of ‘andoung’ logs from Gabon increased from 2700 m³ in 1991 to 47,000 m³ in 1999 and then decreased to 10,300 m³ in 2009. The contribution of Bikinia durandii was probably moderate.

Properties

The heartwood is pinkish brown, slightly darkening upon exposure, and rather indistinctly demarcated from the sapwood. The grain is usually interlocked, texture fine and even.

The wood is medium-weight, with a density of 520–710 kg/m³ at 12% moisture content, and only moderately hard. It air dries fairly well with little degrade, but some care is needed. The rates of shrinkage are moderate to rather high, from green to oven dry 3.2–6.2% radial and 6.7–11.0% tangential.

At 12% moisture content, the modulus of rupture is 82–159 N/mm², modulus of elasticity 10,200–16,180 N/mm², compression parallel to grain 39–66 N/mm², shear 5.5–8 N/mm², cleavage 10.5–22 N/mm and Chalais-Meudon side hardness 2.3–4.4.

The wood works well with both machine and hand tools. In planing operations woolly surfaces may occur due to the interlocked grain; cutting edges should be kept sharp. The wood holds screws and nails well. Gluing properties are good and the wood takes a satisfactory finish. Boring and peeling characteristics are good. The wood is moderately durable, being quite resistant to termite attack, but susceptible to pinhole borer, longhorn beetle and Lyctus attacks. The heartwood is resistant to impregnation with preservatives, but the sapwood is permeable.

Description

• Large to very large tree up to 60 m tall; bole straight, cylindrical, branchless for up to 30 m, up to 130(–150) cm in diameter, with buttresses up to 2.5 m high; bark surface smooth to rough, greyish brown to reddish brown, with reddish lenticels, inner bark fibrous, brownish yellow becoming purplish upon exposure, with a dark red exudate; crown rather narrow, irregular; twigs greyish brown with few pale brown lenticels, yellowish brown hairy to glabrous.
• Leaves arranged spirally, paripinnately compound with (6–)9–16 pairs of leaflets; stipules free, narrowly obovate, up to 6 cm long, early caducous leaving annular scars on twigs; petiole 7–24 mm long, rachis up to 23 cm long, slightly grooved above; leaflets opposite, sessile, oblong, asymmetrical, (0.5–)1.5–10.5 cm × 0.5–3.5 cm, leathery, glabrous. Inflorescence an axillary compound raceme 5–22 cm long, pale brown short-hairy, with up to 12 lateral branches up to 4.5 cm long; bracts up to 1 cm long.
• Flowers bisexual or male, zygomorphic, scented, at base with 2 ovate bracteoles up to 13 mm long; pedicel 4–8 mm long, hairy; sepals 3(–5), small, up to 3 mm long, 2 fused into a 2-lobed band; petals 1–3, white, one up to 7.5 mm long, others up to 2 mm long; stamens 10, 9 fused at base, 1 free, anthers purplish; ovary superior, up to 5 mm long, with 3–5 mm long stipe, hairy, 1-celled, style 9–11 mm long, hairy except at apex; male flowers with reduced ovary.
• Fruit an obovate, flat pod 9–21 cm × 3.5–8.5 cm, with 1–2 cm long stipe, short-pointed at apex, very narrowly winged at upper suture, with a longitudinal vein near the middle of the lateral sides, 1–2-seeded.
• Seeds lens-shaped, 3–4 cm long, with very thin, dark brown seed coat.
• Seedling with epigeal germination; hypocotyl 8–11 cm long, epicotyl 21–30 cm long; first two leaves opposite, with 4–6 pairs of leaflets, subsequent leaves alternate.

Other botanical information

Bikinia comprises 10 species and is confined to rainforest and gallery forest of western Central Africa. It is most closely related to Aphanocalyx and Tetraberlinia.

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; 13: simple perforation plates; 22: intervessel pits alternate; 23: shape of alternate pits polygonal; 25: intervessel pits small (4–7 μm); 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; 46: ≤ 5 vessels per square millimetre; 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.
• Axial parenchyma: 79: axial parenchyma vasicentric; 80: axial parenchyma aliform; 81: axial parenchyma lozenge-aliform; (83: axial parenchyma confluent); (89: axial parenchyma in marginal or in seemingly marginal bands); 91: two cells per parenchyma strand; 92: four (3–4) cells per parenchyma strand; (93: eight (5–8) cells per parenchyma strand).
• Rays: 96: rays exclusively uniseriate; (97: ray width 1–3 cells); 104: all ray cells procumbent; 106: body ray cells procumbent with one row of upright and/or square marginal cells; (113: disjunctive ray parenchyma cell walls present); 115: 4–12 rays per mm.
• Secretory elements and cambial variants: 131: intercellular canals of traumatic origin.
• Mineral inclusions: 136: prismatic crystals present; 142: prismatic crystals in chambered axial parenchyma cells.

(E. Ebanyenle, P. Baas & H. Beeckman)

Growth and development

Flowering trees have been recorded in September. Pollination is by insects such as bees (honey-bees and carpenter bees have been recorded to visit the flowers), but probably also by sunbirds. Fruits take about 5 months to mature. The seeds, having a very thin seed coat, are susceptible to desiccation, which necessitates immediate germination after seed shedding. Seedlings probably need ectomycorrhizal fungi for proper growth.

Ecology

Bikinia durandii occurs in dry-land rainforest up to 600 m altitude. It usually occurs in small groups of about 10 mature trees in the forest, but nearly pure stands of trees with variable bole diameter have also been reported.

Handling after harvest

Logs are susceptible to insect and fungal attacks after felling; they should be removed from the forest as soon as possible or treated with preservatives. Large numbers of longhorn beetles have been recorded on freshly felled boles. Fresh logs float in water and thus can be transported by river.

Genetic resources

Bikinia durandii may become threatened by genetic erosion because it has a small distribution area. It does not seem to be logged much at present, but more intensified logging operations in the future might easily endanger this species. Bikinia durandii is included in the IUCN Red List of threatened species as vulnerable, but its status needs updating.

Prospects

Bikinia durandii provides wood of good quality, and, like some other Bikinia spp., it may have good prospects for planting in timber plantations because it seems to grow quite rapidly into large, straight and cylindrical boles, even on poor soils. However, much research is still needed, especially on propagation and growth, also in relation to mycorrhizal relationships.

Major references

• Aubréville, A., 1968. Légumineuses - Caesalpinioidées (Leguminosae - Caesalpinioideae). Flore du Gabon. Volume 15. Muséum National d’Histoire Naturelle, Paris, France. 362 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.

• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.

• Détienne, P., 2001. Du nouveau chez les andoungs. Bois et Forêts des Tropiques 267(1): 101–103.

• Sallenave, P., 1964. Propriétés physiques et mécaniques des bois tropicaux. Premier supplément. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 79 pp.

• Sallenave, P., 1971. Propriétés physiques et mecaniques des bois tropicaux. Deuxième supplément. Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 128 pp.

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

• Wieringa, J.J., 1999. Monopetalanthus exit: a systematic study of Aphanocalyx, Bikinia, Icuria, Michelsonia and Tetraberlinia (Leguminosae, Caesalpinioideae). Wageningen Agricultural University Papers 99(4). Wageningen Agricultural University, Wageningen, Netherlands. 320 pp.

• World Conservation Monitoring Centre, 1998. Monopetalanthus durandii. In: IUCN. Red list of threatened species. Version 2010.4. [Internet] http://www.iucnredlist.org. January 2010.

Other references

• CIRAD Forestry Department, 2009. Andoung. [Internet] Tropix 6.0. http://tropix.cirad.fr/ africa/andoung.pdf. August 2010.

• 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.

Sources of illustration

• de Saint-Aubin, G., 1963. La forêt du Gabon. Publication No 21 du Centre Technique Forestier Tropical, Nogent-sur-Marne, France. 208 pp.

• Hallé, F. & Normand, H., 1960. Sur une espèce nouvelle d’andoung: Monopetalanthus Durandii (Caesalpiniaceae). Notulae Systematicae (Paris) 16: 136–140.

Author(s)

• E.A. Obeng, Forestry Research Institute of Ghana (FORIG), University P.O. Box 63, KNUST, Kumasi, Ghana

Correct citation of this article

Obeng, E.A., 2011. Bikinia durandii (F.Hallé & Normand) Wieringa. [Internet] Record from PROTA4U. 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. <http://www.prota4u.org/search.asp>.

Accessed 18 December 2024.

• See the Prota4U database.