Detarium microcarpum

Detarium microcarpum (Bambara: Ntamajalan), commonly known as sweet detar, sweet dattock or tallow tree, is an underutilized species of tree legume that grows naturally in the drier regions of West and Central Africa. It has a wide range of uses due to its medicinal properties, edible fruit (eaten raw, cooked, or made into flour with many uses of its own) and hardwood, which is used as fuel. This makes it valuable and appreciated by local communities, but further research and effort are needed for its domestication. D. microcarpum is an African tree belonging to the family Fabaceae (legumes). It is a small tree or shrub growing up to 15 m tall but can reach 25 m in moist areas. In terms of growth rate, the shoots of the trunk can reach a height of 1.5 m – 2 m in 1 to 2 years and are much more vigorous than seedlings which on average grow to 0.6 m after 3 years and may reach 1.5 m in 4 years. It flowers during the rainy season (July to September/November), but the main flowering period only lasts up to 8 days. It bears fruit from September – January/May and in November; the tree sheds its leaves and produces new leaves in March. D. microcarpum occurs naturally in the drier regions of West and Central Africa (Benin, Cameroon, Central African Republic, Chad, Gambia, Ghana, Guinea, Guinea Bissau, Côte d'Ivoire, Mali, Niger, Nigeria, Senegal, Sudan and Togo). Unlike the other species of its family, D. microcarpum grows in dry savanna, while Detarium senegalense grows in the dry forest, and Detarium macrocarpum grows in humid forest. Many different vernacular names exist for this species, including the English, sweet dattock or tallow tree, and the French, dankh or petit détar, as well as Abu-laili (in Sudan) or Tamba Dala (in Mali). Propagation of this species may be vegetative or from seed. It is capable of vegetative propagation by coppice regeneration and suckering from stumps or roots, as well as propagation by rooted cuttings and grafting using scions from mature trees. This species is mainly found on shallow, stony and lateritic soils, often on hills, as well as in regions with an annual rainfall of 600–1000 mm. It is most common in wooded savannahs or savannahs, semi-cleared dry forest areas and fallows, growing in sandy or hard soils with high iron content. The seeds of D. microcarpum can be stored at ambient temperature (26 °C) for 5 years. The seed must be scarified to break dormancy before being planted –scarification through immersion in boiling water or sulphuric acid, and next soaking them in tepid water for 24 hours, or by removing the seed coat with a sharp object. The plant parts are harvested according to need and availability. Fruits are harvested from March to May and can be kept for 1–3 years in jute bags. Leaves are harvested from April to November and roots and bark are harvested year round, all of which are used fresh or dried for future use. Natural germination is hampered by bush fires and dry spells posing a threat to poor farmers. Extensive fruit collection, uncontrolled tree cutting, overgrazing and bushfires pose a threat to the species. D. microcarpum is heat and drought tolerant and capable of thriving on infertile sites. The species is often found in relatively poor soils; farmers can distinguish if land is unproductive if the tree is abundant in that area. The tree bark’s colour may also indicate the fertility of the land, with red indicating fertile soil and black indicating poor soil fertility. This tree shows some pest resistant properties. A methanol extract of the leaves exhibited strong deterrent activity against termites, specifically Reticulitermes speratus. Germplasm collections for D. microcarpum are held at the Institut d’Economie Rurale (IER) in Mali and at the Centre National des Semences Forestieres (CNSF) in Burkina Faso. Trees differ biochemically, in fruit length and width, protein content, with higher dry-matter per unit volume and sugar content in larger fruits than in smaller ones. Differences between tree populations are expressed morphologically based on leaf length, width and area, endocarp shape, seed shape, pulp thickness and number of leaves. The number of leaves has been observed to be inversely proportional to its pulp thickness. This species is highly appreciated by local peoples due to its variety of uses; it is said to be one of the most appreciated in the environments where it occurs naturally. The fruit can be eaten raw or cooked, but for the most part, its pulp is transformed into flour. The seed flour is a traditional emulsifying, flavouring and thickening agent used to prepare cakes, bread, couscous, baby food and local beer. Its seed kernels are added to egusi soup, or are cooked and eaten as vegetables. The leaves are used as a condiment or vegetables, as are its flowers.