The regrowth of Colophospermum mopane following clearing.

Abstract

There is very little data published relating to the regrowth of savanna trees and shrubs in bush-cleared areas. The aim of this study was to provide data and a model to answer the question: 'How long does the beneficial effect of clearing C. mopane last on herbaceous production?' Illustrates with graphs and tables; The recovery of cleared Colophospermum mopane thicket in the eastern Transvaal lowveld, to a level where its effect on grass production is similar to that in the pre-cleared state, occurs within fourteen years. Based on certain assumptions, the 'effective duration' of the increase in grass production after clearing is about half of the recovery period. A model describing the recovery of basal area with time since clearing is presented. Simulations show that the recovery period is shortened by higher rainfall and lengthened by drought. It is hardly affected by the degree of clearing mortality typically achieved by the use of hormonal herbicides, but is extended to twenty-two years if 90% mortality is achieved. Complete clearing mortality and a seedling establishment rate of four seedlings/ha/year results in recovery within forty years.Language: English

Keywords: Bush clearing; Coppice; Modelling; Savanna trees; Shrubs; drought; economics; grass production; mortality; rainfall; recovery; regrowth; seedling establishment; colophospermum mopane; thicket; clearing; eastern transvaal; south africa; transvaal lowveld; model; herbicides; mopane