User:Hoferv

The tree is fast growing and reaches a height between 20 and 50 m with straight trunk which can have a diameter up to 2.7 m. His crown is broad and the roots are big running. The bark is smooth with a grey color. Inside, the bark is red when cut.

Njangsa is a dioecic plant. The flowers are yellowish white, 5 mm long and form a long terminal panicle which measures between 15 and 40 cm. Flowering time is between April and May. Male panicles are larger and slender than female flowers.

At maturity (August - September) the fruit smells like over-ripe apples.

Native geographic location and native ecosystem

Njangsa is endemic to Tropical Africa. The native geographic location of Njangsa reaches from Senegal in West Africa to Sudan, Uganda, and Tanzania and from Sudan down to the western coast of Sub-Saharan Africa to Angola . The tree is also found in Madacascar.

Njangsa grows generally in rain forests and is also typical for secondary forests. This tree is a light-demanding species. Therefore it can also be found in deciduous forests, forest edges, secondary scrubs and thickets in semi-dry savannahs as well as in food crop fields, cocoa farms and other agroforestry systems, where the trees can also intentionally planted.

Products and ecological value

Food-value

The eatable parts of the plant are the high nutritive kernels content in the seeds. The dried and ground kernels are used as a flavoring agent in some dishes in West and Central Africa. The past of ground kernels is used to thicken soups and stews. Oil can be obtained from the kernels. Only a small amount of extracted seed oil is carried out. The oil has a yellowish color and tastes similar to groundnut oil. Because of its high content of γ-tocopherol, the oil is very stable and is becoming rancid only slowly. This oil is interesting as cooking oil, margarine or for soap production and pharmaceutical preparations.

Constituent	Quantity (%)
Water	3.1 +/- 0.8
Fatty acid	47.4-55.30
Crude protein	24.3-65.2
Total carbohydrates	5.6-9.3
Digestible carbohydrates	5.6-9.3
Crude fibres	8.9-9.3
Ash	10.5-17.8
Nitrogen	8.6 +/- 0.9
Dry extracts	97.8
pH	7.84
Energy value	495 kcal/100g

Medicinal value

The extract of bark of the tree is used by traditional doctors as an antidote against poison because the extracts are said to contain lupeol. It is also use to cure various diseases as cough, malaria, yellow fever, stomach pain, rheumatism, etc. Other characteristics are aphrodisiac and anti-inflammatory properties. Seed husk and latex, leaf decoction and sap are also used to treat divers illness

Ecological value

Presence of Njangsa helps to improve soil quality because the roots are colonized by mycorrhizae and because of its natural leaf litter. Burned kernel shells deliver potassium rich ash and the cake remaining after oil extraction from seeds has high nitrogen content. Both products can be used as fertilizer. Njangsa provides shade for humans, livestock and crops and leafs can be used as fodder for livestock during dry season.

Industrial uses

Oil obtained from dried kernel and ash from burned wood can be used for soap and varnish production.

Social and historical implications

In southern Cameroon, dried seeds are used for a traditional game called “songho”. In Sierra Leon they are used for rattles for “bundu” dances and in Nigeria they are used for a game called “okwe”.

Production

Cultivation area

The main production area of Njangsa is the humid forest zone of Cameroon. The tree is one of the commonest seedlings seen in the more open parts of the forest. Consequently the species is abundant in new farming clearings. During these clearings, farmers kept trees from this species.

Yields

The kernel is economically the most important part of the tree. They are collected from the ground between September and October. Njangsa trees yield fruits every two or three years some trees even every year. Each harvest yields up to 900 fruits and an average of 72 kg of kernels.

Cultivars

Njangsa is a new crop and is actively domesticated only since 1995. The knowledge about the genetic diversity is therefore limited. Today, available information about genetic resources is too little, that improvements occur by plant breeding.

Climate and soil requirement

Climatic condition	Minimum	Maximum
Altitude (m)	100	1250
Rainfall (mm)	1000	<3000
Temperature (°C)	18	32

Characteristics	Suitable habitat
Soil type (texture)	Medium textured ultisols and oxisols
Topography	Lowlands
Rooting depth	Freely draining
Soil pH	Acidic, pH 5-6

Best germination success can be observed on a mixture of river sand and forest soil with a ratio of 1:3.

Cultivation technic

Propagation

Propagation of Njangsa is possible by seeds, by vegetative propagation or by grafting. The advantage of propagation by seeds is that the tree develops strong taproot. This is important for the stability of the tree as well as for big exploration zone for water and nutrient up-take. Because Njangsa is dioecic, it is difficult to identify male and female trees before the reproductive phase. Because of high genetic variability, seeds may have different characteristics compared to the parent plant. Vegetative propagation allows reproducing trees with exactly the same characteristics as the selected female tree. Njangsa can also be propagated by grafting. A shoot or bud (the scion) is united with an already established rootstock.

Field establishment

The site should be cleared, especially if the trees are associated with other food crops. Then the young plants can be planted in planting holes separated by 10 m from each other. Before transplanting the plants, they need to spend at least 6 month under shade and need a minimal size of 20-30 cm. After planting, a 1 m high fence of palm fronds for shade should be established, covered at the top, for the first two weeks.

Plant management

Water: The plants need to be watered abundantly after transplanting so that the plant can adapt to the new environment. To avoid high water losses by evaporation, a mulch layer can keep soil moisture. Fertilizer: The establishment and development of this fast growing tree can be improved by supplying it with enough nutrients trough mineral fertilizer. Husbandry: As long as the plant is young, weeding is very important to reduce competition for water and nutrients, so that a fast growth and development is possible. Pest and disease control: No major disease are observed yet. But Njangsa can be attacked by herbivores as caterpillars (Lobobunaea phaedusa, Imbrasia petiveri, Imbrasia obscura, Imbrasia melanops). These caterpillars are eatable and are therefore not treated with chemicals but collected by local population as source of protein. Aphids can infest plants in nurseries. They are easy to detect because the leaves curl as result of an attack. These aphids can be controlled with a systemic insecticide. Once the trees are in the field since more than two years, treatments are no more necessary because of plant vigor.

Harvest and postharvest treatment

First fruit harvest occurs after 6 to 7 years of age in forests or after 3 to 4 years in managed plantations. The fruits are picked up by hand from the ground, once they are ripe enough to drop from the tree (September-October). To facilitate harvest, the ground under the tree should be cleared. Once harvested, the fruits are placed on a pile for two to three weeks so that the pulp is rotting faster and the seeds can be extracted easily.

Extracting the kernel from the pulp is a time-taking process because of their hard shape. After boiling them in water, cooling them down, the kernel are extracted one by one with a knife or nails. Then the kernels are sun or fire dried. Njangsa is stored as seed or as kernel. If they are well dried, they can be stored up to two years on a dry place.