Agroforestree Database

Local names:
 English (melia), Somali (boba,baba)

Melia volkensii is deciduous, open crowned and laxly branched. Mature trees range between 6 and 20 m tall. Trees with 25 cm diameter are common. The bark is grey, fairly smooth, furrowing with age.

Leaves are a light, bright green, bipinnate with (sub)opposite leaflets, 3-7 per pinna, up to 35 cm long, and are densely hairy when young. The leaflets are oval to lanceolate, tapering to the apex. The margins are entire or serrated, becoming almost glabrous when mature. Dimensions range between 4 and 7.5 cm long.

Flowers are small, white and fragrant, in loose sprays. Male and female flowers are on the same tree (andromonoecious). Inflorescence is congested, up to 12 cm long, axillary and on older branchlets. Petals are tetra- to pentamerous, white, free and may curl backwards; stamens are the same number as the petals, sometimes twice as many, and united into a tube.

The fruit is drupe-like and oval; colour changes from green to pale grey as the fruit matures. Fruit size is normally 4 cm long with a very thick, bony endocarp.

Because of the divided leaves, the generic name is derived from the Greek melia (the ash).

Ecology

M. volkensii is common in association with acacia-commiphora vegetation. It is an emergent in acacia-commiphora deciduous bushland, sometimes fringing seasonal watercourses or appearing on rock outcrops.

Native range
Ethiopia, Kenya, Somalia, Tanzania

Tree management

Almost all growers plant M. volkensii irregularly dispersed within crops, generally at spacing in excess of 10-15 m. Some farmers plant trees along boundaries but rarely near dwellings as branches tend to break off during storms. The tree tends to develop heavy lateral branching; therefore farmers prune M. volkensii from the 1st year onwards to maintain a clean straight bole. When the crown is fully developed, it is thinned heavily each year to reduce shading on underplanted crops like sorghum and millet. The operation is carried out in the dry season to provide clear conditions at planting time. Pruning with the flush of new leaves and fruits coincides with the time when fodder is scarce. Some farmers pollard their trees, believing that this induces an increase in diameter. Many farmers, however, believe that pollarding induces rot and is counter-productive.

Seed storage behaviour is orthodox, and viability can be maintained for several years in hermetic storage at room temperature with 11-15% mc. Preliminary results on germination trials at the Kenya Forestry Seed Centre, using seeds stored for 3 months at -3 deg. C, obtained a mean germination of 3%. Other reports from the centre are that mature and properly dried 'stones' can be stored in air-tight containers at a temperature of 3 deg. C for several years without damage. Seeds were extracted with a pocket knife before a seed extractor was designed in 1994. On average, there are 200 extracted seeds/kg, depending on provenance and the climatic conditions of the ripening year.

M. volkensii is common in association with acacia-commiphora vegetation. It is an emergent in acacia-commiphora deciduous bushland, sometimes fringing seasonal watercourses or appearing on rock outcrops.

Commonly used propagation methods include transplanting from wildlings, transported either from the bush or from arable land during the rainy season, and root cuttings arising from accidentally or deliberately damaged roots. Many farmers in Kenya do not prefer root cuttings as it results in unstable trees. There has been little success with vegetative propagation using stem cuttings. There is no literature on grafting and air-layering, suggesting that it has not been tried.

After dispersal, the seeds can be dormant for 2-5 years before germinating naturally. They are therefore scarified using fire (fast fires or dry grass dung) before planting. Another scarification method involves breaking the caruncle at the micropyle end, cutting longitudinally through the integuments, perisperm and endosperm from the centre to the micropyle end, then soaking the seeds in water at ambient temperature for 6 hours. This method was found to give up to 64% germination rate in a study at Kitui, Kenya. 

M. volkensii is a fecund species, with seasonal yield of between 600 and 10 000 viable seeds per tree. There are approximately 200 stony endocarps per kilogram, from which 4 480 intact seeds can be obtained, assuming they are not damaged during extraction.

Poison:  Leaf preparations are used as flea and fly repellents; they are said to be particularly effective on goat kids. Antifeed activity against Schistocerca gregaria is reported; larvicidal and growth inhibitory effects have also been observed against mosquitoes.

Farmers believe leaf fodder is of high quality for both cattle and goats. The tree comes into leaf and is pruned for fodder towards the end of the dry season, a time when fodder is extremely scarce. Goats eat the large, fleshy drupes after they fall. The fruit pulp is reported to contain almost 10% crude fat and over 12% crude protein; the mature leaves are reported to contain over 5% crude fat and 21% crude protein.

Apiculture:  M. volkensii is one of the principal species used to make log hives because the wood is easily worked and shaped. The flowers are said to provide excellent bee forage.

Branches lopped during routine management and to provide fodder are often left to dry in the field before being used for firewood. The firewood produces an unpleasant smoke, and the tree is said to produce poor quality charcoal.

Timber:  The wood is easily worked and shaped, making it suitable for making acoustic drums, containers and mortars. The coarse-textured heartwood with a density of around 0.62 works easily, planes well, is durable and extremely termite and decay resistant comparing favourably with Ocotea usambarensis, Vitex keniensis and Khaya species. The timber is valued locally for door and window frames, doors shutters, rafters, poles and furniture. 

Soil improver:  A few farmers have suggested that the heavy leaf fall of M. volkensii during the later stages of crop development may increase crop yields.

Intercropping:  Most farmers in Kenya believe that M. volkensii is compatible with all crops grown. This, however, is dependent upon good silvicultural practice in reducing the shade effect of canopies, which would otherwise adversely affect light-demanding crops such as sorghum and millet. Due to its deep rooting nature, its interference with ox-plough cultivation is minimal.