Bush control with fire in Acacia nigrescens/Combretum apiculatum savanna in Botswana

Abstract

The results of a trial to study the effects of periodic burning or complete resting, on the vegetation and some soil characteristics of semi-arid Acacia nigrescens/Combretum apiculatum savanna in eastern Botswana are discussed. Plots of 1,2ha were burned at intervals of 0 (not burn control), 1, 2, 3, 4 and 5 years from 1958 to 1980. In 1981 these were assessed for bush density by species and by height classes, for grass basal cover and botanical composition, and for soil properties. Bush density increased with increasing burning interval but complete resting suppressed seedling development. All burned plots were visibly more open than the rested plot and hence fire appears to offer the possibility of a low cost means of bush control. The changes in soil properties, grass cover and botanical composition resulting from low frequency burns were small.

Keywords: bush control|fires|savannas|Botswana|burning regimes|periodic burning|resting|vegetation|soil factors|semi arid grasslands|bush densities|botanical compositions|soil properties|seedlings|grass cover|vegetation surveys|species lists