The agricultural and forest products of British West Africa

by Gerald C. Dudgeon

RUBBER TREE TAPPED, HERRING-BONE SYSTEM IMPERFECT, ABURI.

Fig. 21, [p. 61.]

If the herring-bone cuts were made carefully upon the lower part of the trunk, and attention given to their depth and direction, the tree might be preserved for a longer period. An illustration given shows the incorrect mode of tapping, where the transverse cuts are opposite instead of alternate ([Fig. 21]). Experiments seem to show that there is not the same “wound response” in the case of Funtumia trees as is found in that of the “Para” tree (Hevea brasiliensis); the paring of the wounds some days after tapping yielding no flow of latex similar to that procured in the first instance. On cutting the bark area between the transverse channels, the latex cells appeared to be empty and to indicate that a large area is drained on the first tapping. Further investigation is necessary in order to compare the results obtained from this tree with those of Hevea.

The latex of Funtumia will remain in an uncoagulated state for a longer time than that of Hevea, but it may become damaged by fermentation if a quantity is kept in bulk for a lengthened period. The native does not usually produce a pure Funtumia rubber, but mixes with the latex the latices of several other plants, among which may be named “Odum” (Chlorophora excelsa), “Osese” (Funtumia africana), “Ofo,” “Okre,” “Sindru” (Conopharyngia crassa and Alstonia sp.). Having mixed some of these latices with that of the Funtumia, the whole is heated and poured into a hole in the ground, which has been prepared to serve as a mould. Coagulation and decomposition proceed together at a slow rate, and finally produce a rubber containing a number of holes which serve as receptacles for the liquefied decomposed constituents. The rubber mass is black outwardly, but whitish within, and is more or less sticky. It is said that the latex of Landolphia owariensis, the vine from which “Krepi ball” rubber is made, is sometimes mixed with the rest to hasten coagulation.

Improved Methods.—In 1906 attention was drawn to the use of a plant called “Niama” in the Ivory Coast, by which Funtumia rubber latex was coagulated by adding a hot decoction of the leaves. This plant was subsequently found to be Bauhinia reticulata, which bears the name of “Otakataka” in the Gold Coast. Experiments with this afforded excellent results. An examination of the plant made at the Imperial Institute proved that the tannin contained in the leaves was responsible for the coagulation of the latex, and that the infusion of any plant containing tannin is equally effective. The obstacle to the general use of B. reticulata for coagulation, is that the plant does not occur in the same localities as the wild Funtumia tree. Doubtless other tannin-yielding plants may be found in the rubber forests which would answer the purpose equally well, among them the pods of Acacia arabica. A simple method of coagulation, which was demonstrated to the chiefs and rubber collectors in 1908, is that of diluting the latex with about four or more times the volume of water, straining and boiling it, when the rubber quickly separates and can be collected from the surface of the water by means of a stick and immediately pressed into a rough biscuit.

The rubber made in the manner mentioned above has been valued at more than twice the price obtained for the adulterated stuff, but it appears difficult to persuade the local merchants to offer a higher price for it, and it therefore suits the rubber collector better to make the inferior quality. So long as this state of things continues, it is to be feared that instruction in the improvement of quality will not lead to the adoption of better methods.

In 1908 a Commission of Enquiry was appointed and made certain recommendations for legislation for the protection of the industry. Articles on Gold Coast rubber will be found in the Bulletin of the Imperial Institute, vols. viii. (1910), x. (1912), xi. (1913), xii. (1914), xii. (1915) and xv. (1917).

Plantations.—Large numbers of Funtumia seedlings have been grown at and distributed from the Government Botanic Gardens at Aburi, Tarkwa, and Kumassi, and some of the Ashanti kings and chiefs, who have expressed a wish to attempt to renovate their rubber forests, have obtained assistance from the officers of the Agricultural Department, who have conducted planting operations in the forests in the presence of those interested. Plantations under European management and with European capital are in progress in the vicinity of Axim and Sekondi. Most of the recently made plantations are said to consist more of Para than of Funtumia rubber trees, although in 1913 one of these in the Dunkwa district of Ashanti was reported to contain 20,000 trees of the latter kind. The tree appears to thrive well when planted closely, and straight trunks are soon formed.

Insect Pest.—At Aburi and elsewhere the Funtumia tree is found to be attacked by the larva of a moth of the family Pyralidæ, identified as Glyphodes ocellata, Hampson, which denudes it of leaves. No severe damage seems to be done by this pest, which has only been observed in plantations, and was destroyed at Aburi by repeated applications of lime and ashes.