C2. Hill miombo woodland and scrub

Julbernardia-Brachystegia lower escarpment and hill miombo woodland covers much of the lower Muchinga Escarpment and its attendant foothills, Chinshenda, Soma and the Mvumvwe range. It is also found on the upper valley floor where it may intergrade with vegetation types D1 and D2.

Vegetation type C2 can be separated into two subtypes according to substrate and vegetation physiognomy. Subtype 1 is miombo scrub woodland, associated with the thin, eroded, stony soils of the hill slopes. Subtype 2 is open woodland, found on the deeper soils of the interfluves and flatter sites.

Vegetation type C2, subtype 1 (scrub woodland) is recognized by Astle et al. (1969) who refer to it as “Miombo scrub on shallow soils”. This type is also described by White (1983), in a direct reference to the Luangwa valley (p.99). Fanshawe (1971), Naylor et al. (1973) and Phiri (1989) all refer to this distinctive form of miombo as “Scrub miombo woodland”. Vegetation type C2, subtype 2 (woodland) is designated “Miombo woodland on deep soil” by Astle et al. (1969). This terminology also embraces upper escarpment miombo woodland (C1, subtype 1), but Astle et al. make topographic and floristic distinctions which place this type on the interfluves of the upper valley floor (land system 7; facet 1). Phiri (1989) cites Brachystegia boehmii, B. bussei, B. manga and Julbernardia globiflora as common taxa in this habitat.

Subtype 1 - Brachystegia stipulata-Julbernardia globiflora miombo scrub woodland

Miombo scrub woodland occurs at elevations ranging from 700m to 1000m and is the most extensive vegetation type of the lower Muchinga escarpment, where it occurs in mosaic with subtype 2. It also intergrades with vegetation types D1 and D2 on the upper valley floor.

Subtype 1 occurs on the shallow, slightly acid (pH 6.6-6.9) light grey to yellowish brown, generally stony sandy clay loam soils (lithosols and shallow fersiallitic soils) associated with the hill slopes of the lower escarpment and foothills.

The vegetation takes the form of 3-5m tall scrub woodland, in which there are very few tall trees, Brachystegia bussei being an infrequent exception. In this habitat the vegetation is dominated by Julbernardia globiflora, Brachystegia allenii and Brachystegia stipulata in stunted form. Brachystegia manga is locally dominant on Chinshenda hill. Other common small trees and shrubs are Brachystegia boehmii, Diplorhynchus condylocarpon, Combretum zeyheri, Pseudolachnostylis maprouneifolia and Monotes africanus. The grass layer is sparse, but similar in composition to that found in vegetation types C1 and D2. Typical grasses are Trichopteryx fruticulosa, Tristachya bequaertii, Diheteropogon amplectens, Sporobolus myrianthus, Andropogon spp. and Melinis spp. Common subshrubs include Ochna leptoclada, Ochna richardsiae and Cyphostemma spp. Characteristic herbs are Chlorophytum rubribracteatum, Ectadiopsis producta, Endostemon dissitifolius, Indigofera sutherlandoides, Justicia striata, Zygotritonia nyassana, Becium spp. and Commelina spp.

Subtype 2 - Julbernardia-Brachystegia open miombo woodland

Julbernardia-Brachystegia open miombo woodland is found in the deeply dissected terrain of the lower Muchinga escarpment and its foothills, where it occurs in mosaic with miombo scrub woodland (Subtype 1). It also intergrades with the Combretaceae woodlands and wooded grasslands, D1 and D2, on the upper valley floor.

Subtype 2 is found on the deep, yellowish brown slightly acid, sandy soils associated with the hill tops and ridges of the lower escarpment and foothills.

The vegetation takes the form of open woodland with scattered tall trees (15-20m) and a well-developed grass layer, dominated by tall species. Shrub patches are occasional. Characteristic tall trees include Burkea africana, Julbernardia globiflora, Pericopsis angolensis and Brachystegia allenii. Common small trees include Brachystegia stipulata, Combretum zeyheri, Terminalia sericea, Combretum psidioides and Oldfieldia dactylophylla. The shrub layer is reduced but includes Ozoroa insignis, Diplorhynchus condylocarpon, Vernonia glaberrima and Lannea discolor (also a small tree). Common grasses are Andropogon chinensis, A. gayanus, A. schirensis, Hyparrhenia anemopaegma, H. filipendula, Hyperthelia dissoluta and Tristachya superba. Like the grasses, the herb component is related to that of vegetation types D1 and D2 (below); typical species include Acalypha allenii, Acalypha villicaulis, Barleria fulvostellata, Dicoma anomala, and Agathisanthemum spp.