Sunday, February 12, 2012

Acacia albida











Acacia albida is also known botanically as Faidherbia albida and the Swahili name we used was Mgunga, which is known a a strong upright tree.
Mgunga is indigenous to the Middle East and much of Africa - the drier, semi-arid areas, as well as riverine zones in Tanzania where it will grow to an elevation of 1800m. The species generally prefers well drained soils.

Description: Mgunga is one of the tallest of the Acacias - to 30m, with a high rounded crown. It is deciduous often spring to life just before the rains. The branchlets tend to zigzag and are shiny grey. Bark is dull grey, fissured with scales. Thorns are in pairs and often pointing downwards - straight about 2cm. Leaves are compound 3 -8 pairs of pinnae each with 5-25 pairs of grey/green leaflets up to 1cm - rounded and overlapping. Flowers are slender spikes to 14cm, creamy white and attractive to bees, fragrant and appear before foliage. Fruit are distinctive twisted pods, twisted and brown-orange to 25cm long, thick - especially the edges, containing >20 distinctive, hard seeds.

Uses: Timber - local construction, firewood and charcoal, posts, utensils, food flavoring (pods), stock fodder (especially the fallen pods), shade, nitrogen fixation (soil conservation).

Propagation: There are >9000 seeds per kg with 75% viability. Seeds are able to be stored for a long period if kept dry and free from insect attack.
Nicking the seed before direct sowing provides the most even germination. Treating with hot water and soaking for 24 hours is effective but needs to be repeated on seeds that do not swell on the first attempt.

The pods fall to the ground and are much liked by livestock. Of all the indigenous trees that we supplied, Mgunga was the most widely accepted. This is because it is useful and farmers liked the fodder supplied.
In some areas where the tree was unknown, we had to do some talking for the species to be accepted.

After outplanting, the tree grows rapidly - which is a good thing because it does not have to be protected from browsing animals for an extended period.
The species is good to shade crops because it does not compete and enriches the soil.


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