Brachystegia boehmii and Brachystegia floribunda facilitate the establishment of montane forest trees in miombo woodland in northern Malawi

Abstract

Sparse vegetation (i.e. savannah and woodland) interspersed with patchy forests (i.e. rain forest and montane forest) is typical of many tropical regions. Forest trees seldom establish adjacent to these sparsely vegetated areas because the adjacent vegetation is often more resistant to fire and water stress, and competition from grass species. However, these limiting factors may not apply under a closed crown due to a facilitative effect. Here the effect of a closed crown on the establishment of montane forest trees in miombo woodland in northern Malawi was determined. Environmental conditions, the number of saplings of montane forest trees and their regeneration mode were all studied. Result showed that grass cover is reduced and water stress can be ameliorated under a closed crown of Brachystegia boehmii and Brachystegia floribunda, which are the dominant trees of miombo woodland. Numerous montane forest tree saplings were found under the closed crown. These results indicate that a closed crown of B. boehmii and B. floribunda has a facilitative effect on the establishment of montane forest tree in miombo woodland.