Entandrophragma roburoides Vermoesen

Entandrophragma utile is a large tree up to 60 m and more in height, with a DBH of more than 250 cm. Crown regular with few massive branches, leaves clustered at branchlet ends. Bole long, cylindrical, scarcely tapered; butresses rounded, extending up the bole for 2-5 m. Bark thick (up to 4 cm) grey-brown, regularly cracked and fissured into squarish, scale-like pieces which persist on the tree. Leaves pinnate, up to 50 cm long, leaflets 16-32, opposite, subopposite or alternate, oblong-lanceolate, up to 14 x 5 cm; apex gradually acuminate, base unequally rounded and usually subcordate; lower surface almost glabrous; venation closely reticulate. Leaf petiole slightly winged, covered with short rusty hairs. Inflorescence up to 20 cm long, calyx tomentollous, scarcely lobed. Petals 0.5 cm long, densely puberulous to tomentollous. Staminal tube 0.3 cm long, urceolate, margin subentire. Capsule club-shaped, rounded at the apex, 14-21 x 4.5 cm; valves 0.8 cm thick, thickened and incurved at the apex, dehiscing from the apex and remaining firmly attached at the base. Seeds 9.5 x 2 cm, dark brown, obliquely truncate at the base. The leaves of this species are easily mistaken for those of Canarium schweinfurthii in herbaria. This tree has been extensively exploited in Nigeria, Cameroon and the Central African Republic. Its wild populations are greatly diminished.

E. utile is a hermaphroditic species, new leaves sprout at the beginning of the rainy season. Fruits are wind dispersed.

E. utile is a climax community heliophyte- light demanding species. In Uganda it grows in mixed to climax rain forests. E. utile is primarily a lowland tree species occuring between 0-500 m in West Africa and below 1 400 m in Uganda. It normally occurs with other Entandrophragma spp.

E. utile is propagated largely from seedlings and wildings, rarely raised by direct seeding. Planting of 3-4 month old E. utile seedlings in polythene bags, although reliable, involves subsequent difficulties in tending because of the small size of the stock. The seedlings develop a long taproot and if potted should be transplanted early to prevent root coiling at the pot or polythene bag base. In nurseries the seeds are sown in pots or seed beds, and the young plants raised in the nursery for 1-2 years; during this time the roots must be cut back several times. Planting stock should be at least 50 cm tall before outplanting. Good results are achieved with seedlings whose roots have been pruned to the size of the planting hole (40 x 40 x 40 cm) and with striplings. Planting of stumps is not practical.

E. utile is a light demanding species requiring 50-90% of full daylight, however young seedlings require shading until fully established. Once at the sapling stage they demand a great amount of light. The species grows slowly; diameter growth rates of 1.0-1.5 cm per annum can be expected. Seedlings should be protected from browsers.

Poria [Oligoporus] placenta and Nodulisporium sp. cause decay of E. utile wood. Fusarium, Gibberella fujikuroi and Nectria rigidiuscula infect E. utile seeds. The borer Xylosandrus compactus attacks young shoots. Trunk rot by Phellinus spp. and other fungi reduces value of mature timber. Their fatty seeds are avidly devoured by animals, a fact that interferes with natural regeneration.

Seed storage behaviour is orthodox, seeds tolerate dessication to 4% moisture content, 92% germinate following 240 days subsequent hermetic storage at 2 deg C. Soaking in water for 12 hours hastens germination. Seeds are hand picked and there are 1 880 seeds/kg. Seed damage by insects can be prevented by adding ash in storage containers.

Erosion control: Important in protecting soil from erosive activities of water. Shade or shelter: Mufumbi is an ideal shade tree. Reclamation: E. utile is used in afforestation in Cote d’Ivoire.

Fodder: Leaves browsed by animals. Fuel: E. utile is an excellent source of fuel wood and charcoal. Timber: Produces an excellent timber, specific gravity about 0.54-0.75 g/cu cm, similar to that of mahogany (Khaya spp.), reddish in colour and fine grained, with multiple uses in high class joinery and furniture, canoes, railway coachwork, plywood manufacture and decorative veneer. The wood seasons well and is easy to work. Its natural durability is good, it glues well, has good strength attributes for fastening with nails and screws, and can be easily processed. Large quantities, of ready or part sawn timber are exported to Europe. Wood drying was significantly affected by temperature but little affected by pressure, high pressure causes excessive thickness shrinkage. Drying defects were considerably reduced by starting with a temperature of 120 deg C and increasing it by 10 deg C steps to a final value of 150 deg C at a constant pressure of 15 Kp/sq cm (Okoh 1984). Medicine: The bark of this tree is used in Cameroon to treat malaria and bark extracts have displayed fungicidal activity against Pyricularia oryzae. This plant is traditionally used in Nigerian medicine, and is claimed to achieve complete healing of peptic ulcers in humans. Tests in mice and rats supported these claims at least in part. Other products: A sterol, 7alpha,20(S)-dihydroxy-4,24(28)-ergostadien-3-one, has been isolated from the bark of E. utile. Other compounds isolated from the bark are the tetranortriterpenoids utilin B & C, and entilin D, a heptanortriterpenoid.