Rotational woodlots take their turn
A massive destruction of forests occurred in the Tanzanian miombo woodlands early this century. In the expert opinion of the time, eradicating tsetse meant destroying their habitat. The tsetse may have disappeared, or at least declined to manageable levels, but so has the vegetation that provided fuelwood for local people and fodder for their livestock. Nowadays farmers use valuable organic material such as cow dung and crop residues for fuel, depriving the soil of nutrients essential for fertility. With rising populations and large numbers of cattle dependent on the land, the problems are becoming increasingly serious. However, in the Shinyanga region, ICRAF researchers and local farmers are testing rotational woodlots that could provide a solution for some of these problems.
Traditional woodlots tend to be stands of a single tree species planted to provide fuelwood and timber or poles for construction. ICRAF's idea of rotational woodlots is to integrate useful native trees such as Acacia polycantha and A. nilotica into a cropping system of maize, sorghum or millet thus doubly benefiting from the services and products that trees can provide.
To establish woodlots, tree seedlings are planted amongst the food crops. The young trees benefit from the care given to the crops and are protected from termites and grazing livestock. After 2-3 years of cropping, the tree roots and canopies begin to interfere with the crops so the land is left fallow and the trees are allowed to flourish . Usually, farmers encourage an undergrowth of palatable herbaceous and shrubby species as fodder for their livestock, maintaining the local Shinyanga tradition of 'ngitiri' (dry season fodder reserves). If some nitrogen-fixing species are sown, the soil fertility can also be improved at the same time.
After 2-4 years of fallow, part or all of the woodlot is cut down or coppiced and used for firewood or construction whilst the cleared land is sown with crops for another 3-4 years before being left to fallow once more. The time cycles for the rotational woodlots may, however, vary according to the farmer's individual needs for crops, fodder or wood production. Other valuable products that can be harvested from the woodlots include honey, beeswax and mushrooms. Participating farmers and extension officers have shown great interest in the rotational woodlots and initial on-farm trials are very encouraging.
