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ADANSONIA DIGITATA*

DISTRIBUTION

Tolerates a wide range of vegetation types including scrub, wooded savannah hot, dry areas, and semiarid to subhumid tropics south of the Sahara. In Tanzania it grows from the coast to 1250 m (RSCU 1992). Prefers arid areas and well-drained sandy sites between 450 and 600 m above sea level, with a rainfall of 300 to 500 mm per year (Palmer and Pitman 1972).

Minimum Altitude (m):

0

Maximum Altitude (m):

1500

Minimum Rainfall (mm):

90

Maximum Rainfall (mm):

1500

Minimum Temperature (C):

20

Maximum Temperature (C):

30

REQUIREMENTS

Soil Requirements: Prefers sandy topsoil over loams, but can tolerate poorly drained heavily-textured soils. Does not occur on deep sands. Tolerates both acid and calcareous soils (FAO 1988).

Light Requirements: Strongly demanding.

Influential Factors: No serious pests or diseases are known to affect the tree. A. digitata can host many noxious crop insects. It is deep rooted, drought sensitive, and fire resistant. It prefers a high water table (RSCU 1992). The tree is often browsed by elephants.

PROPAGATION

Means of Propagation: Seedlings and cuttings.

Seeds per kg:

2500

Seed Sources:

800 TSH per kg - Tanzania National Seed Centre 1991.

Seed Treatments: Fruits are very large, 10 to 26 cm long, and with a woody shell. Each pod contains about 100 seeds with a thick, hard coat. Fruits should be collected from healthy trees. Break open and extract black seeds inside, which ripen from December to February. Put the seed in water and remove any that float. Some sources say seed treatment is apparently unnecessary. The only effective pretreatment is to crack the seed coat, but this can damage the seed (Teel 1984). Other recommended methods are to immerse seed in boiling water, remove immediately and let cool, or boil in water for 5 to 7 minutes. Acid seed treatment could be tried (don Maydell 1986).

Seedling Management: Germination is poor and the seed coat can be easily damaged. The germination period is extremely variable, between 3 weeks and 6 months. Seeds may take up to a year to germinate in the pot, but should germinate well in the nursery where adequate moisture can be provided regularly. In the wild, seeds are thought to germinate only in exceptionally good rainy seasons. Attempts to propagate vegetatively are reported to have failed, and planting by seed may be the only means of propagation. Seeds apparently keep their viability for years if stored in a cool dry place (Palmer and Pitman 1972).

SILVICULTURE

Planting Types: Found as isolated trees only, usually in or near settlements.

Growth Factors: Fairly fast growing once it is established (2 m height in 2 years and 12 m height in 15 years) (FAO 1988). Growth varies according to age, with young trees adding 30 cm per year in diameter, while older trees grow more slowly. Baobabs are sensitive to drought and even to a short dry season. At such times girth may actually diminish in size (Palmer and Pitman 1972).

Growth Cycle: One of the longest living trees in the world (3000 years). Fruits are edible from April through June; leaves are edible in October and November. Fruit is produced from 8 to 23 years onward (FAO 1988).

Limitations to Planting: Young trees are rarely found. Reasons may be due to the intensive browsing of young plants by livestock and the excessive use of leaves for food by people (don Maydell 1986). Elephants find the whole tree palatable up to 3 years of age.

Management Systems: Should be transplanted at the beginning of the rains. Optimal spacing is thought to be 20 to 30 m apart. Needs to be protected against fire and browsing until well-established (FAO 1988).

IMPORTANT USES

Use # 1: FOOD
The fruit, leaves, and flowers are very important in terms of their nutritional value. Both the fruit and leaves are high in vitamin C. The seed and flower are high in protein, and the kernel contains an edible oil. Fruits are commonly seen in markets throughout Tanzania. Young sprouts are consumed as a vegetable but are considered to be a famine food.

Use #2: MEDICINE
The various parts of the baobab are used to treat a large number of ailments. Nearly every part of the tree has some medicinal value. A few include: powered bark mixed with porridge for malaria; the pulp of the fruit is mixed with honey and is used for coughing; the leaves are used for diarrhoea, fever, inflammation, kidney and bladder diseases, blood clearing, and asthma; the leaves also serve as emollients and are used to help extract guinea worm; the fruits and seeds are used for dysentery, fever, haemoptysis and diarrhoea; dry powered roots are prepared as a mash for malaria; and gum from the bark is used for cleaning sores (Westman Draft).

Use #3: FIBRE
Bark fibres are used for making ropes, baskets, snares, cloth, strings for musical instruments, mats, and hats. The root bark also makes good rope. When the sap flows a section of bark can be unrolled, usually without hurting the tree.

OTHER USES: The baobab has over 30 uses and it is recognized as one of the most useful trees in East Africa. As a result it receives voluntary protection and local veneration throughout Tanzania.


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