Ecological studies of the vegetation of the Sudan. 1. Acacia senegal (L.) Willd. and its natural regeneration.
A study of the size, age and density of stocking of A. senegal in a series of plots in Kordofan showed that the species is still capable of maintaining itself by natural regeneration over many parts of the former Gum belt of the Sudan, where the average annual rainfall is 300-450 mm., provided that the local system of land use is favourable. The present failure of A. senegal to regenerate over parts of the belt is apparently attributable to changes in the distribution and density of the population and the consequent changes in the lengths of the cropping and bush-fallow stages of the usual agricultural cultivation cycle. A shortening of the bush fallow and lengthening of the cropping stage are inimical to the persistence and regeneration of A. senegal. Where soil deterioration has led to the abandonment of cultivation, recolonization by A. senegal is slower and more hazardous than formerly, because of the smaller number of seed parents available, increased grazing pressure and greater frequency of grass fires. Maintenance of stocks of the species by planting or raising seedlings at appropriate stages of the cultivation cycle is suggested. The silvicultural characteristics of A. senegal, which behaves like a pioneer woody species rather than a major component of closed stable forest, are discussed in relation to its survival.KEYWORDS: Abies senegal \ Regeneration \ natural regeneration \ natural regeneration \ relation \ ecological \ edaphic factors \ plant succession \ relation \ shifting cultivatior \ vegetation types \ tropical dry