Effects of previous cultivation on regeneration of Julbernadia globiflora and Brachystegia spiciformis in grazing areas of Mupfurudzi Resettlement Scheme, Zimbabwe

Abstract

We investigated the effects of previous cultivation on regeneration potential under miombo woodlands in a resettlement area, a spatial product of Zimbabwe's land reforms. We predicted that cultivation would affect population structure, regeneration, recruitment and potential grazing capacity of rangelands. Plant attributes for Julbernadia globiflora and Brachystegia spiciformis were measured in previously cultivated and uncultivated sites making up rangelands of the scheme. Their population structure showed a high regeneration potential with different recruitment mechanisms, either coppicing or seedling emergence. Brachystegia spiciformis populations had more adult trees, and its saplings were more abundant in uncultivated sites while regeneration on cultivated sites was mainly from coppices. Julbernadia globiflora had fewer adult trees but high seedling and sapling densities, especially on cultivated sites, while coppicing was low and more common on uncultivated sites. This suggests that cultivation would favour vigorous recruitment of J. globiflora, while B. spiciformis would become more abundant in the absence of cultivation. This varying recruitment of the two woody species is likely to modify and influence state-and-transition dynamics in a miombo woodland, thus affecting the resultant tree population structure and grass biomass yield and quality.