Quantitative Analysis of Ngoma Forest in Kafue National Park, Zambia

Abstract

Ngoma Forest is one of the eleven major vegetation types in Kafue National Park. Between 1997 and 2002, a study was undertaken to quantify the vegetation and landscape of Ngoma Forest. The key vegetation measurement variables taken from fourteen 20m X 20m sampling plots were: height, diameter at breast height (DBH) and crown size. In addition to vegetation measurements, data on terrain, soil, water and fire occurrence were recorded from each sampling plot. Observations regarding the presence of faunal species were done based on actual sightings and signs such as droppings, nests, foot prints, debarking of trees, feathers, hairs and sounds. Results of the study indicates that Ngoma Forest terrain is almost flat to very flat with generally straight slope of 0 to 3% and altitude ranging from 1,050m to 1,120m above sea level. The Forest occurs on strong acidic and well-drained sandy-clay and sandy-loam with pH range of 4.4 to 5.3. Baphia massaiensis, Friesodielsia obovata, Baikiaea plurijuga, Pterocarpus lucens, Combretum celastroides C. mossambicense , and C. elaeagnoides contribute more than 80% to the physical structure. The tree layer consists of tall trees in the height range of 18 to 22m and is dominated by Baikiaea plurijuga and Pterocarpus lucens with isolated stands of Entandrophragma caudatum, Ficus sur, Burkea africana and Erythrophleum africanum . The second layer consists of trees above 6m but less than 18m and is characterized by Philenoptera violacea, Pterocarpus rotundifolius, Xeroderis stuhlmannii, Dalbergiella nyasae, Strychnos potatorum and S. pungens . The third layer consist of small trees and shrubs rarely reaching the height of 6m and is characterized by Croton megalobotrys, Friesodielsia obovata, Combretum elaeagnoides, C. mossambicense, C. celastroides, Duranta erecta, Citropsis daweana, Grewia flavescens, Dalbergia martinii, Pteleopsis anisoptera and P. myrtifolia . The species diversity of Ngoma Forest is relatively low but comparatively higher than Mopane, Combretacea and Acacia woodlands. The tree / shrub density calculations indicated 1,475 stems per hectare while the mean biomass calculations were 122.6 tons per hectare and 1.5 tons per hectare for trees and shrubs respectively. The extent of Ngoma Forest in 1985 was 34km 2 but the Forest had shrunk to about 18km 2 by 2002. The Forest is likely to shrink further while the scrubland around the Forest is going to expand. This habitat shift is bound to adversely affect the habitat range of a number of ungulates, carnivores, primates, rodents and birds. Some management interventions have been suggested in order to protect this unique habitat.