Local names:
English (yellow pine,white afara,limba,black korina), French (limba,frakè), German (limba), Spanish (akom), Swahili (mwalambe), Trade name (limba,korina,afara), Yoruba (afara,afa)
Terminalia superba is a large tree, up to 50 m tall and 5 m in girth, bole cylindrical, long and straight with large, flat buttresses, 6 m above the soil surface; crown open, generally flattened, consisting of a few whorled branches. Bark fairly smooth, greying, flaking off in small patches; slash yellow. Root system frequently fairly shallow, and as the tree ages the taproot disappears. Buttresses, from which descending roots arise at some distance from the trunk, then support the tree. Leaves simple, alternate, in tufts at the ends of the branches; deciduous, leaving pronounced scars on twigs when shed. Petiole 3-7 cm long, flattened above, with a pair of subopposite glands below the blade; lamina glabrous, obovate, 6-12 x 2.5-7 cm, with a short acuminate apex. Nerves 6-8 pairs; secondary reticulation inconspicuous. Inflorescence a 7-18-cm, laxly flowered spike, peduncle densely pubescent; flowers sessile, small, greenish-white; calyx tube saucer shaped, with 5 short triangular lobes. Petals absent. Stamens usually twice the number of calyx lobes (usually 10), in 2 whorls, glabrous; filaments a little longer than calyx; intrastaminal disc annular, flattened, 0.3 mm thick; densely woolly pubescent. Fruit a small, transversely winged, sessile, golden-brown smooth nut, 1.5-2.5 x 4-7 cm (including the wings). Nut without the wing about 1.5 x 2 cm when mature, usually containing 1 seed. The generic name comes from the Latin ‘terminalis’ (ending), and refers to the habit of the leaves being crowded at the ends of the shoots.
Ecology
T. superba is essentially a tree of deciduous forest and sheds its leaves in the dry season. It is characteristic of tropical high secondary forest areas with a dry season of about 4 months, but it does not respond well to long dry spells, especially on sandy soils. The species is especially plentiful at some distance from the coast, but it gains at the expense of the rainforest following clearances. The tree will withstand occasional flooding. It is frequently struck by lightning, presumably because of its dominant position in the forest. It is very fire sensitive. However, its wide spread owes a great deal to the activities of man and to its pioneering characteristics; light demanding, wide crown and production of regular quantities of viable seed.
Native range
Angola, Benin, Cameroon, Central African Republic, Congo, Cote d'Ivoire, Democratic Republic of Congo, Equatorial Guinea, Gabon, Ghana, Guinea, Liberia, Nigeria, Sierra Leone, Togo
Tree management
The young tree grows straight and vigorously in full light, particularly if its crown is free, but stagnates under shade. In the oldest stands in Congo, which are now 30 years old, a spacing of 12 x 12 m appears to be appropriate, and trees are straight and vigorous. Natural pruning is excellent and starts early, at 3-4 years, and from then onwards the degree of self-pruning has a strong effect on the health and future value of the tree. It coppices readily from tree stumps, bears copious amounts of seed every year, and under plantation conditions achieves sexual maturity after 6-10 years. The rotation period as applied in favourable locations in Africa is 40 years.
The seeds store well in sealed containers with a little desiccant at 2-4 deg. C, giving 40-60% germination after 1-2 years, but poor storage conditions reduce germination to about 30% after 1 year. There are usually 8000-10 000 seeds/kg of air-dried seed with wings attached; if in good condition they will produce 6000-7000 good planting stock. There are approximately 10 000 wingless seeds/kg.
T. superba is essentially a tree of deciduous forest and sheds its leaves in the dry season. It is characteristic of tropical high secondary forest areas with a dry season of about 4 months, but it does not respond well to long dry spells, especially on sandy soils. The species is especially plentiful at some distance from the coast, but it gains at the expense of the rainforest following clearances. The tree will withstand occasional flooding. It is frequently struck by lightning, presumably because of its dominant position in the forest. It is very fire sensitive. However, its wide spread owes a great deal to the activities of man and to its pioneering characteristics; light demanding, wide crown and production of regular quantities of viable seed.
Seed is abundant and easy to collect; in general it is collected between November and January in the northern hemisphere, and between July and September in the southern. The 1st seed crops are often of a low germinative capacity; about 60-80% is obtained. No pretreatment is needed and seed should preferably be fresh at sowing, covered with fine soil and watered morning and evening. Germination takes place in 2-4 weeks, and temporary shading is necessary. Germination is epigeal; the cotyledons emerge folded then extend, thicken and become somewhat oblong, kidney shaped and with triple base venation. The root develops clearly as a taproot. Direct sowing of T. superba is rarely done and not very effective; the normal method is raising nursery stock. Planting out normally takes place at 6 weeks. There is no difficulty in grafting the species, and this has been practised in Congo since 1970. Here the optimum period was found to be mid-August to mid-September before the rise of sap and recurrence of the rains, with scions grafted at once, or transported under refrigeration.
Fibre: T. superba has potential importance in paper making, offering the capability of producing a relatively wide range of pulps. The fibre has a flexibility factor of 70-79%, high values that suggest good tear-and-burst strength. The yield of raw chemical alkaline pulp is 40-50%, depending on the degree of lignification. The wood may be used in the manufacture of cellulose, panelling and also as particle boards.
Timber: The wood is normally creamy white with no noticeable distinction between sapwood and heartwood. The log varies from 50 to 120% mc, depending on the time that elapses between felling and conversion. After exposure to the air, it darkens slightly, verging on a tanned appearance, and resembling a light oak. Three types of commercial limba are recognized: white or straw coloured; black, olive-grey to blackish-brown; and multicoloured, with dark and light streaks. The wood is soft to medium hard, light in weight, somewhat weak, easy to saw and machine, and accepts paints and varnish well. The density of the wood is 480-650 kg/m³ at 12% mc. It can be used for many purposes and is widely known and used, particularly in Belgium, Germany and Switzerland. Used in plywood manufacture, furniture, joinery, for plinths, mouldings, general fittings, and door faces and, after suitable treatment, for external joinery.
Intercropping: T. superba has been used for mixed farming; associate species pairs such as T. ivorensis and T. superba; T. superba and Triplochiton scleroxylon are common.