Agriculture

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Browsing Agriculture by Subject "Bush thickening - Namibia"

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    A crude quantification of wood that is and can be harvested from bush thickening species in Namibia.
    (Namibia, Ministry of Environment and Tourism, 2002) Zimmermann, Ibo; Joubert, David F.
    The increasing rate at which thickening bushes are being harvested in Namibia requires better information on the availability and sustainability of the resource, in order to improve management. Two sources of data from the literature were combined to give a rough approximation of the standing biomass of wood of appropriate size for charcoal production, in each of nine bush-thickened zones. The overall estimate came to roughly 135 million tons of dry wood in about 260 000 square kilometres of Namibia, or an average of just over 5 t/ha. The legal commercial harvest for the 1999/2000 financial year came to the equivalent of just under 0.2 million tons of dry wood. Interviews with ten charcoal producers, and field data gathered at one site, suggest that harvesting could take place at intervals of roughly 20 years, provided that harvesting is selective and leaves sufficient bushes of different size classes for regeneration. However, it is likely that subsequent harvests would be lower and more difficult to obtain. Previously chopped bushes could then only be re-harvested on every third or fourth cycle, preferably after being pruned to maintain a more appropriate growth form, which is easier to harvest and more conducive to grass growth.
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    The effect of a prescribed burn, followed up with browsing pressure, on rangeland condition in the mountain savanna and karstveld of Namibia.
    (DINTERIA, 2002) Zimmermann, Ibo; Mwazi, Fidelis N.
    Measurements were taken before and after the application of a prescribed burn, aimed at controlling bush thickening, on a commercial farm in the Mountain savanna and Karstveld of Namibia. The high fuel load, due to high rainfall during the previous season, resulted in an intense fire that caused considerable top kill of bushes. However, the bushes, dominated by Dichrostachys cinerea, resprouted at varying time intervals after the fire, mostly from the ground level. The occasional goat browsing pressure that was subsequently applied was insufficient to keep the majority of bushes under control. Hence browsing pressure would need to be applied more frequently and over a longer time period after a fire, in order to keep more of the bush regrowth under control. The goats also grazed significantly on the regrowth from perennial grasses. Therefore the browsing pressure should not be excessive, as the goats also threaten the perennial grasses.