The agricultural and forest products of British West Africa

by Gerald C. Dudgeon

The fibre may be prepared by stripping the bark layers from the soaked stalks and beating these upon the surface of the water until the actual bark is removed, when the fibre may be dried in the sun; being finally picked over to get rid of the small remaining bark particles.

The plant exhibits some advantages for cultivation over jute, in that it may be cropped twice in one year and treated as a perennial. Collection of the wild growths would be unsatisfactory for the production of the fibre upon a large scale, owing to the time occupied in searching for the plants, but it seems probable that the plant would repay planting, especially if some better method of extraction were devised.

The composition, quality, and commercial value of a large number of fibres obtained from plants indigenous to, or cultivated in, the Gold Coast are discussed in Selected Reports from the Imperial Institute, Part I., “Fibres” (Colonial Reports, Miscellaneous, Cd. 4588, 1909), pp. 43, 51, 84, 89, 90, 115.

SILK.—A species of wild silkworm is commonly distributed throughout the forests to the north of Kumassi, and has been identified as Anaphe venata. The silk cocoons of this species and those of Anaphe infracta are used in Nigeria for spinning into yarn for weaving the “Saṉyaṉ” cloths of that country, but no use is apparently made of them in Ashanti. The worms live in small colonies, and form their cocoons in a common envelope of silk, from which two or three somewhat tubular processes project to enable the moths to emerge when the time arrives. The food plant of the silkworm has not been definitely ascertained, but, as the cocoons are found on a large number of herbaceous plants as well as trees, it seems probable that several plants are eaten by it. The quality of the silk is said to be good, and the colour is usually a golden or light brown.[3]

COPAL.—The tree which produces this resin, often miscalled “gum,” which is commercially known as “Accra copal,” occurs throughout the forests of Ashanti and Akim, and has not yet been specifically determined. Investigations have shown that it is allied to Cyanothyrsus oblongus, Oliver, which yields the “Ogea” resin of Lagos, and which belongs to the Natural Order Leguminosæ. The flowers obtained from the Ashanti trees are of a similar construction to those of Cyanothyrsus.

Locally the resin is commonly used for torches and for the preparation of a scented pigment called “Krobo,” which is used for elaborating patterns upon the skin, being commonly employed by the Akim people for this purpose. For export the chief value is for the preparation of varnish.

The quantity exported reached 178 tons in 1907, after which it declined, and now no longer reaches a significant figure. The overwhelming interest attracted by cocoa has led to its disappearance. Cf. Selected Reports Imperial Institute, pt. ii., “Gums and Resins” (Col. Rep. Misc., Cd. 4971, 1909), pp. 172-5; Bull. Imp. Inst., vol. xii. (1914), p. 220.

The copal-yielding trees are generally of immense size, and the resinous liquid may be observed exuding from the main trunk as well as the branches, in such a way as to form elongated “tears” or slabs, which harden on exposure to the air. When these become brittle they are broken off by wind and fall to the ground. Often the flow of resinous liquid seems to be so profuse that quantities reach the ground and form what is termed “fossil copal,” owing to the fact that it is dug from the ground beneath the trees.

There is evidence to show that in some instances the original flow of the resinous liquid is caused by deep borings in the sap wood made by insect larvæ (probably Coleoptera—beetles), signs of which are commonly apparent on old trees, which yield the most copal. Specimens of branches, which have been tunnelled by these larvæ, have been collected, exhibiting all the cavities filled with hardened resin.

Compared with the copal produced by Copaifera Guibourtiana, a tree which is found in Sierra Leone, the Ashanti product is much inferior, although the price paid renders it sufficiently valuable for collection and export. Several different types of the Accra copal are known, some of which appear to be of less value than others, although apparently yielded by the same tree. That which is deemed preferable is clear and pale yellow; milky pieces should be sorted out, as they are valued at a lower figure. Blocks have been obtained which weighed over twenty pounds. Sorting is said to have been adopted by some of the local merchants, and as high a price as 60s. per cwt. is reported to have been obtained for sorted copal.