Termite resistant timber in Kenya's drylands

Termite resistant timber        by Mwangi Mumero

While acacia may be the most useful tree species in dry parts of the country, the World Agroforestry Centre (ICRAF) has highlighted the need for farmers in these regions to diversify into other useful trees.

Among the most useful tree species is Mukau tree (Melia volkensii) that does well in dry parts of the country.

Mukau is mainly planted for its timber, which is durable and termite-resistant.

According to ICRAF researchers, the timber is used for construction industry as well as for furniture. It is also the timber of choice for those in the bee-keeping industry because it is well suited for making log hives as the wood is easy to work with and shape.

The prices for Mukau timber are usually good. The timber fetches four times higher prices compared to cypress timber, between Kshs.600 and 1,000 in Kitui. 

In lower parts of Embu, the prices range between Kshs.2, 500 - 3,000.  The timber is valued locally for door and window frames, doors shutters, rafters, poles and furniture.

Harvested poles, felled in less than four years can fetch up to Kshs.60 on the farms and over Kshs.150 in Kitui town.

Mukau is a deciduous tree, 6 to 10m tall. Its diameter is typically about 25cm.

First of all, the natural range of Mukau tree (Melia volkensii) is the Eastern African counties of Kenya, Ethiopia, Tanzania and Somalia.

In these countries, it is found at altitudes ranging from 350m to 1700m, the mean annual rainfall being 300-800mm. The common English name is 'Tree of Knowledge.'

It is found common in deciduous bushland in association with Acacia-Commiphora vegetation.

Mukau can grow on most soils, although it prefers well-drained soils: sandy soils, clays, shallow stony soils. Some of the districts it grows in Kenya include Embu, Samburu, Isiolo, Marsabit, Meru, Kitui, Machakos, Taita Taveta, Wajir and Kilifi Districts.

This natural range is characterized by much climatic variability and seasonal drought. As a coping strategy, the water content in the roots, leaves and stems of this tree increase with increasing water stress.

“Even with the dry weather, the leaves of this tree remain green and watery- good fodder for livestock”, observes Kilonzo Wambua, a farmer in Kitui County.  

It coppices well and is fast-growing with a rotation of 10 to 15 years. The flowers of the wood also provide excellent bee forage.

Its twigs, leaves and fruits are good as fodder for livestock, especially during the dry season.
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 while the mature leaves are reported to contain over 5 per cent crude fat and 21 per cent crude protein.

The tree is also usually planted around homesteads for provision of firewood and shade.

Like the neem tree (Azadirachta indica), the tree also contains compounds that are toxic to insects; extracts from its fruits were traditionally used to control tick and fleas.They are said to be particularly effective on goat kids.

 Research has also shown that extracts of Mukau possess larvicidal, growth-inhibiting and anti-feedant effects on insects. In fact, extracts from the tree have been used against the desert locust (Schistocerca gregaria) - an added benefit for the arid lands. And because of the fact that both neem tree and Mukau belong to the same family and as a result of possessing similar phytochemical profiles, they may have similar bioactivity characteristics.

This would be a boost to traditional medicine, which has so far been using mainly neem tree.

 In human medicine, Mukau may have some properties against some tumor cell lines.

Mature seeds can be collected all-year-round. One grown Mukau tree can produce up to 300kgs of fruits a year. At harvesting time, the fruits have high moisture content about 40 per cent- and must be dried.

 The tree is currently in high demand by Kenyan farmers because of its compatibility with other crops, its insect- and drought-resistant traits, use as fodder and timber, and also because of the high demand for timber in the country because of the ban on logging in place.

Its seedlings can fetch a high a price as Ksh. 200.

  The tree has unorthodox germination. Its biggest constraint would be the propagation problems: it exhibits poor germination performance, with high mortality in young seedlings. (ENDS)