Difference between revisions of "Raphia hookeri"

Uses: Raphia hookeri yields two valuable types of fibre: piassava or bass, and raffia. The very strong piassava fibre is obtained from the petiole and leaf sheath and is used locally to make weather-resistant coarse ropes, belts for climbing oil-palms and brushes. It is exported for the production of hard brooms and brushes. Piassava fibre is used to make exceptionally strong paper. It can also be used to produce very fine-textured charcoal, much favoured for the manufacture of home-made gunpowder. The soft but strong raffia fibre has also been considered a potential source of pulp for paper production. It is obtained by pulling off ribbon-like strips from the upper surface of the leaflets of young unfolding leaves and is used to make mats, hats, baskets, bags, ropes, hammocks, ceremonial costumes, etc. It may be woven into cloth. In Europe it is used as tying material for horticulture and handicrafts. The leaves of Raphia hookeri, often split lengthwise, are used for thatching, though they last only 1 year. They are also used to make mats, baskets and other articles of wickerwork, and are used for hut-walls and fences. The midribs and petioles of the leaves (‘raffia bamboo’ or ‘bamboo’) are used for poles, rafters, ladders, furniture and cross-bearers in canoes. Split lengthwise they are used to make screens. Sap tapped from the stem when the tree nears the flowering stage ferments rapidly into palm wine (‘mimbo’), a very popular drink throughout West Africa. In Nigeria it is bottled for commercial purposes, although there is a risk that bottles can explode due to continuing fermentation. The wine is distilled into a strong alcoholic liquor and can also be used as bakers’ yeast. The young terminal bud or ‘palm cabbage’ is eaten as a vegetable. The raw fruit is sometimes used to flavour food, but elsewhere it is considered poisonous, and it is crushed for use as fish poison. Boiled or roasted kernels are sometimes eaten. In Ghana the leaf juice is used for the treatment of laryngitis and lactation failure. Boiled fruits are eaten in Nigeria. The oily mesocarp is used in traditional medicine for its laxative and stomachic properties and as a liniment for pains. The ash of burnt and ground roots mixed with palm oil is instilled into the ear for the treatment of otitis. Larvae of the rhinoceros beetle (Oryctes sp.), found in rotting stems, are collected and eaten. (PROTA)

Production and international trade: Raphia hookeri is the main piassava yielding Raphia species. Its piassava has been exported to temperate countries (mainly Europe) for the production of brooms and brushes since the end of the 19th Century, when the supply of South American piassava (from Attalea funifera Mart. and Leopoldinia piassaba Wallace), used in Europe for brooms since the middle of the 19th Century, could no longer meet demand. The trade reached its peak in the 1950s and 1960s (7000 t exported from Sierra Leone, the main exporting country, in 1964; 5300 t from Nigeria in 1966; there was also trade from Guinea), after which it declined with the advent of plastic brooms. The particular qualities of African piassava for broom-making are such that it still enters the international market. The main types of African piassava fibre in trade are ‘Sherbro’, ‘Sulima’ and ‘Calabar’ (‘Opobo’). Sherbro and Sulima are obtained from the petiole, the former from Raphia hookeri and the latter from Raphia palma-pinus (Gaertn.) Hutch., often with an admixture of Raphia hookeri fibres, whereas Calabar is extracted from the leaf sheath of Raphia hookeri. The leaf sheaths of Raphia palma-pinus are rather short and do not yield high quality fibre. Most of the raffia of commerce is produced in Madagascar from Raphia farinifera. (PROTA)

Although palm wine is the main product of Raphia hookeri in several regions, no production data are available. The wine is mainly used and traded locally. Distilled palm wine is also mainly traded locally although there is some trade between neighbouring countries. (PROTA)

Anatomy: The hypodermis of Raphia hookeri leaflets consists of thick fibres arranged in a continuous ribbon-like layer with no discontinuities. In Raphia vinifera the fibres are not arranged in a ribbon-like layer, but are discontinuous, resulting in less tenacity. In both the stem and petiole the vascular system consists of bundles which are scattered throughout the ground tissue and the cortex is very narrow or non-existent. The peripheral vascular bundles of the central cylinder are congested and have a well-developed fibrous sheath. The vascular bundles are separated by parenchyma. In the inner part of the central cylinder, the vascular bundles are more diffuse than in the periphery. Stem fibres are more numerous than in the petiole, partly because the vascular bundles are closer and partly because the fibrous bundle sheaths are thicker in the central parts. Growth and development Raphia hookeri develops in accordance with Tomlinson’s growth model. When young the main stem forms a few basal suckers. Raphia species have monocarpic stems, i.e. they flower and fruit only once, followed by death. Inflorescences are produced more or less simultaneously in the axils of the most distal leaves. Tapping for wine may damage the developing inflorescence, making flowering impossible and accelerating death. The time from planting to flowering in Raphia hookeri is 3–7 years. In Nigeria, Raphia hookeri flowers in May. The pericarp reaches maturity at 24–30 months, the seed matures in about 30–33 months. Lipid accumulation in the pericarp mainly occurs between 30–36 months after pollination. Ground squirrels, bats and birds feed on the mesocarp. (PROTA)

Propagation and planting: Managed stands of Raphia hookeri are mostly left to rejuvenate naturally by seed. In Nigeria, selected trees are left untapped for this purpose. Occasionally, Raphia hookeri is propagated from seed. The 1000-seed weight is about 25 kg. The germination period may range from 1–24 months, and the germination rate from 30–60%. Young plants are easily transplanted. In nurseries, a spacing of 30 cm × 30 cm is recommended. It has been claimed that seeds should be sown ventral side upwards, because the embryo is located on this side, but research has shown that seed orientation does not influence germination or seedling growth. In Nigeria, Raphia hookeri sometimes serves as support for yams. In Benin, tomatoes, cassava, sugar cane, red pepper and other crops are sometimes grown on earth ridges in Raphia hookeri swamps. (PROTA), edric.

Management: In West Africa, Raphia hookeri is exploited from natural stands, but it is also planted and tended on upland farms. Suckers are often removed by farmers to promote growth of the main stem. (PROTA), edric.

Diseases and pests: Raphia hookeri in Nigeria is affected by seedling blight, caused by Glomerella cingulata. Symptoms are transparent yellow circular spots appearing on the youngest fully expanded leaves, later becoming necrotic and coalescing. The infection spreads from the tip to the base of the leaflet and may lead to leaflet shedding. Severely infected seedlings may die. Fruit rot, caused by Thielaviopsis paradoxa (synonym: Chalara paradoxa), also occurs in Nigeria, causing dark brown rot of the mesocarp. It is a weak pathogen entering fruit via wounds, sometimes killing the embryo, and leading to loss of planting material. The aphid Cerataphis palmae may cause considerable damage, e.g. in Nigeria. (PROTA)

Harvesting: Because palm wine from Raphia hookeri is highly prized, cultivators are reluctant to diminish plant vigour by cutting leaves for their fibre. However, dying leaves can be harvested for piassava with little effect on wine yields. Removing the leaf sheaths requires considerable leverage, and is usually a team effort. Stout poles, flattened at the end, are inserted into the suture of the lowest leaf sheath and the stem, and the sheath is levered away, while additional weight is applied to the petiole. As it is easier to remove the leaf sheaths from a fallen trunk, palms are often felled after tapping and before fibre harvesting. In Nigeria, external fibres covering the trunk are sometimes set on fire, after which the tree is felled with an axe, the leaves and lower trunk are cut off with a cutlass, and the leaf stalks are cut and removed from the base to the crown successively. Tapping for palm wine begins when the first small leaf (2–3 m long) subtending an inflorescence appears. A cavity is cut in the stem just below the growing point and the resulting sap is collected in a calabash. When sap flow diminishes, the hole is enlarged until it is about 50 cm × 20 cm. Raphia can usually be tapped for 18–25 days before the tree dies. Unlike oil palm, Raphia palms are rarely felled before tapping. For maximum oil yields, the fruits should be harvested 36–42 months after pollination. (PROTA)

Native to tropical western Africa, this massive palm is found in swampy lowland areas predominantly along the coast from Senegal southwards into the Congo basin. It is a large tree with a trunk to over 15 m (50 ft.) tall and long, upright, densely plumose leaves with a beautiful, feathery appearance that nearly double this height. One leaf holds up to 360 arching leaflets that are to 5 cm (2 in.) wide and 1.5 m (5 ft.) long and are dark green above, grayish white and waxy below. The trunk is usually solitary and densely clothed in the long, curly, ribbon-like fibers of the leafbases that shed with age. Essentially a palm for the tropics, the Wine Palm develops with breathtaking speed. It appreciates heavy feeding and watering and thrives in boggy ground. In Africa it is popularly cultivated, mainly as a source of building material and for tapping its sugary sap that is fermented into an alcoholic product that we dare not call wine. Despite its many virtues, it is very rarely seen in cultivation outside Africa. (RPS.com)