Introduced Species.—Experiments have been carried on for several years with “Para” rubber (Hevea brasiliensis), “Ceara” (Manihot Glaziovii), and Castilloa elastica, all indigenous to South America. The last-named has been so badly attacked in the Botanic Stations by boring beetle larvæ that it has shown no promise of success. Ceara grows well, but for some reason the production of latex from it is uncertain, and this has caused little value to be attached to it in the Gold Coast, although in the drier region of Togoland this species is being planted. Para rubber seems to show much better results, although, up to the present, no extensive experiments to ascertain the yield of rubber have been made. Tapping two trees growing at Aburi, Mr. Johnson obtained a larger quantity of latex than from Funtumia elastica under the same conditions; and following this an extensive area was planted with Hevea trees at the Tarkwa Botanic Gardens, where the experiment appears to be proving successful. Views are given of a tree at Aburi ([Fig. 20]). Large plantations of Hevea are being made near Tarkwa, Axim and Sekondi as well as in the Kwahu district, where the tree seems to thrive remarkably well. A few of these plantations made returns in 1913 showing promise of success. At one, on the Offin river, there were said to be 90,000 Para trees of different ages, 20,000 Funtumia and 6,000 coffee (C. robusta). At another the yield of rubber from a number of mature trees gave an average of 1·08 lb. of dry rubber per tree in eight months’ tapping, and a third had 22,000 Para trees of which about 8,450 had been tapped and yielded 10,565 lbs. of rubber, or 1¼ lb. per tree tapped. Labour was reported plentiful and good. There are said to be many more rubber plantations in the country from which returns had not been received. Up to 1913 the Agricultural Department had distributed 250,000 Para seedlings and 1,500,000 seeds.
Commenting on the fluctuation in the exported amounts of rubber, His Excellency the Governor (Sir Hugh Clifford), in his message to the Legislative Council in October 1918, explained the recrudescence during 1916 and 1917 as due to the development of rubber plantations under European control. It remains to be seen whether the Gold Coast will be able to successfully compete in this work with the Far East. Articles on Para rubber from the Gold Coast are to be found in the Bulletin of the Imperial Institute, vol. x. (1912), vol. xi. (1913), vol. xii. (1914), vol. xv. (1917) and vol. xvii. (1919).
PALM OIL AND KERNELS.—Records are available showing that the export of palm oil from West Africa has continued for over one hundred years, but the quantity shipped from the Gold Coast during the last fifteen years shows a rapid decrease from the average of the twenty years previous.
The tree which yields the oil of commerce is known as Elæis guineensis, Jacq., and is placed in the Tribe Cocoineæ of the Natural Order Palmæ, together with the genus Cocos, to which the Coconut palm belongs. (Cf. Bull. Imp. Inst., 1909, p. 357; 1920, p. 209.)
Habits of the Oil Palm.—The oil palm occurs most plentifully in the moist regions near the coast, although it will not thrive on land which is perpetually marshy. The palm becomes scarcer when the dense forests of Ashanti are reached, but it is not entirely absent until the ultra-forest tract commences.
The tree often bears fruit when it has only attained the height of ten feet, which it is said to do about the seventh year, but the yield is supposed to increase annually until the tree is thirty or more years old, often continuing for a much longer time. It is not possible to give any positive assurance on this point, as observations have not been recorded for any length of time.
Although the oil is principally obtained from wild trees, one extensive plantation in the Krobo Hills has been successfully carried on for many years by the chief of Odumassi. His trees are planted at regular intervals and care is given to their upkeep and cleanliness. Concessions have recently been granted to Europeans for planting as well as exploiting the wild palms, and experimental work in the mechanical extraction of pericarp and kernel oil have given some promise. Two British companies that have erected extraction plants in the Western Province have laid tram-lines designed to keep them constantly supplied with the palm fruit.
Trees that have become old and practically barren are usually tapped for the extraction of “palm wine,” being frequently cut down for the purpose. In some parts of the country fruitful trees are tapped while standing, and, as this necessitates the base of the terminal shoot being cut into, the tree is generally killed in consequence.
Two crops of fruiting heads are yielded by a tree in full bearing each year, but the autumn crop is heavier than the earlier one, and the aggregate weight of fruit yielded by a tree in one year is generally estimated at 40 lbs.
The fruiting heads consist of large bunches which hang from near the crown of the tree, and each fruit is partly enveloped in a husk-like covering. When removed from this it is found to be smooth, somewhat conical or irregularly compressed, tapering towards an abrupt point. The colour when fresh varies from orange-red to nearly white, with a more or less broad black apex. In section it appears to be composed of a thick fibrous layer over a hard, somewhat rounded stone, which contains a whitish kernel. It is from the fibrous portion, which is included in what is botanically termed the pericarp, that the oil is obtained, but the kernel also contains another valuable oil, for the extraction of which it is shipped to Europe to a large extent.