Abstract

Although, human activities have caused major losses of tropical forest, there are also reports of forest encroachment and expansion into surrounding sparse vegetation types (savannah and woodland). Large savannah-woodland trees may promote forest encroachment into their surroundings by facilitating seed deposition and subsequent establishment of forest species. This work sought to determine whether large individuals of the woodland tree Brachystegia floribunda facilitate encroachment of montane forest tree species. To this end, environmental parameters, seed rain and seedling distribution of montane forest tree species were examined in south-east Africa. The seed rain and the numbers of tree seedlings were both higher below large B. floribunda trees than below: (i) small specimens of this woodland tree and (ii) in open grassland. Moreover, large individuals of B. floribunda modified microhabitat conditions more than small trees. Thus, large B. floribunda trees probably facilitate the encroachment of montane forest trees into surrounding woodlands.

Key words: Brachystegia floribunda, tropical forest, grassland, woodlands.