Vitellaria paradoxa

Cultivation Details

Shea butter tree is a plant of the drier lowland tropics, usually at elevations up to 600 metres, though it can also be cultivated at elevations up to 1,500 metres^{[1, 2]}. It grows best in areas where annual daytime temperatures are within the range 24 - 38°c, but can tolerate 18 - 43°c^[2]. It prefers a mean annual rainfall in the range 500 - 1,000mm, but tolerates 300 - 1,800mm^[2]. Grows best in a sunny position, tolerating light shade^[2]. Succeeds on a variety of soils such as clay; sandy clay; sand; stony soil and laterites. It prefers colluvial slopes with moderately moist, deep soils, rich in organic matter^[3]. Plants can also succeed in poor, lateritic soils^[4]. Prefers a pH in the range 6 - 7, tolerating 5.5 - 8^[2]. There are two main forms of the plant:- Subspecies paradoxa grows at lower elevations, mostly at 100 - 600 metres, though it can be found as high as 1,300 metres^[3]. The mean annual temperature in its range is 25 - 29°c, with a mean annual rainfall of 600 - 1,400mm and 5 - 8 months dry season where the precipitation is less than 50 mm^[3]. Subspecies nilotica is found at the somewhat higher elevations of 450 - 1,600 metres where the mean annual rainfall is 900 - 1,400 mm and there are only 3 - 5 dry months^[3].. Shea butter trees have been protected by farmers for many centuries in the West African savannah, particularly where cattle are scarce. Productive trees are retained when new fields are cleared, leading to areas in Sudan where more than 40% of the trees are Shea butter. Natural regeneration is favoured by fallow of at least 5 years. Shortening the fallow period leads to insufficient regeneration. In areas of cultivation, shea butter tree is found in association with annual crops, such as pearl millet, sorghum, groundnut, cotton, cassava, yams and vegetables^[3]. The tree produces a taproot up to 1, occasionally 2 metres long; with shallow lateral roots that are concentrated at a depth of 10 cm and extend up to 20 metres outward from the tree; and secondary lateral roots growing downwards to the same depth as the tap root^[3]. The taproot and secondary root system strongly develop during the first few years of growth. This enables the seedling to produce new shoots when the original ones are damaged by drought or fire^[3]. Early stem growth is slow; branching occurs after 4 - 7 years. The tree begins flowering at the age of 10 - 25 years. Early flowers may be sterile. Maturity is reached at 20 - 45 years and the total lifespan is around 200 - 300 years^[3]. Leaf fall, flowering, flushing and the onset of fruiting occur during the dry season. Leaves drop mostly at the beginning of the dry season. Trees are rarely completely leafless, or only for relatively short periods. Flowering occurs from the beginning to the middle of the dry season. About 25% of the flowers set fruit. Fruits develop in 4 - 6 months; maturation peaks in the rainy season^[3]. Productivity of the trees is variable. In a sample taken in Burkina Faso, the best 25% of the trees produced 60% of the yield, while the poorest 30% of trees produced little fruit^[3]. A good tree can bear on average 15 - 30 kg fruits per year. In a good year this may be as much as 50 kg, but then only about 15 kg in the next two years^[3] Although a clear production cycle is not confirmed, observations show a tendency for trees to give only 1 good harvest every 3 - 4 years^[3]. Although the trees are fire tolerant, their growth and fruiting are affected by fire. Therefore, trees must be protected by ring weeding^[3]. The tree is an important source of honey. Beehives placed in its branches are assured a good supply of nectar and pollen^[3].