Colophospermum Mopane Tree Forest on Punda Maria Ecca-Shales (Karoo System). Gertenbach Landscapes 15 Kruger Game Reserve
Colophospermum Mopane Forest.
Mopane shows in 2 distinct forms in different parts of the Kruger … shrub form seems to dominate while the forest or tree Mopane areas are much less dominant. If this has ever puzzled you here’s the answer.
Location and Geomorphology
This landscape occurs in the vicinity of Punda Maria on the Ecca-shales of the Karoo System. It is situated between the basalts and the Waterberg Sandstone and extends from Vlakteplaas in the south to the Levubu River. Elsewhere in the KNP a comparable mopane forest occurs, but then it is usually on alluvial soil close to larger spruits and rivers. Examples of this mopane forest is south of the Letaba River, along the Nwanedzi, Tsende, Mpongolo and Shisha. In the latter eases the parent material of the soil is mostly granite. It is a flat to concave landscape and is drained by the tributaries of the Shisha. The altitude varies between 360 and 420 metres above sea level.
Soil Pattern
The soils in this landscape are usually deep with a strong structure in the subsoil and rich in salts especially sodium salts. These salts possibly originated from the shales from which the soils developed. The following soil Forms and series are the most common: Swartland-Uitsicht/Brokespruit/Malakata/Nyoka, Valsrivier/Craven/Lindley/Valsrivier and Zuiderzee. Hutton soils are usually those with a massive apedal structure such as Hardap, Shigalo, Shigalo, Shorrocks and Makatini. Sterkspruit soils also occur. According to Van Rooyen (1978), the pH of the soil varies between 6.1 and 8.7. The soils of this landscape are similar to those of the Acacia welwitchii-thickets.
Vegetation
Van Rooyen (1978) describes the vegetation structure of this landscape as a high tree savanna. Colophospermum mopane-trees of between 10 and 15 metres high make up the most important component of the landscape (Fig. 33). Other trees and shrubs which occur are Spirostachys africana, Acacia nigrescens, Euclea divinorum, Grewia bicolor, Ximenia americana, Maeru parvifolia, Zanthoxylum humilis, Thilachium africanum, Acacia grandicornuta, A. tortilis, Combretum imberbe, C. hereroense, Dichrostachys cinerea, Boscia albitrunca and Dalbergia melanoxylon.
Dominant grasses are Enteropogon macrostachyus, Enneapogon cenchroides, Chloris roxburghiana, Panicum maximum, Aristida congesta subsp. barbicollis, Digitaria eriantha var. Pentzii, Tetrapogon tenellus, Bothriochloa radicans and Schmidtia pappophoroides. Forbs which commonly occur are Amaranthus thunbergii, Hibiscus micranthus, Seddera capensis, Elytraria acaulis, Abutilonfruticosum, Crotalaria virgulata, Indigofera vicioides and Neuracanthus africanus.
The typical structure of the vegetation of this landscape is according to Van Rooyen (1978) as follows:
| Stratum | Percentage Crown Cover |
| >6 metres | 5.7 |
| 3 – 6 metres | 21.7 |
| 1 – 3 metres | 30.1 |
| 0 – 1 metres | 9.5 |
Climate
The landscape receives an annual rainfall of between 500 and 550 mm which is restricted to the summer months. The summers are hot with cool winters and frost being the exception. The prevailing temperature of the landscape must be extrapolated from the two weather stations at Shingwedzi and Punda Maria (Tables 6 and 7).
Table 7 … Temperature data for Punda Maria
… (Data collected since September 1981)
| Month | Average Daily Maximum |
Absolute Maximum | Average Daily Minimum |
Absolute Minimum |
| January | 34.4 | 41.4 | 21.2 | 17.5 |
| February | 31.7 | 39.0 | 19.8 | 16.0 |
| March | 31.7 | 38.0 | 19.8 | 14.5 |
| April | 29.3 | 34.0 | 16.6 | 12.0 |
| May | 26.2 | 31.4 | 12.7 | 8.3 |
| June | 24.6 | 28.0 | 9.8 | 8.0 |
| July | 25.0 | 32.6 | 12.8 | 7.4 |
| August | 26.4 | 36.0 | 14.1 | 9.9 |
| September | 27.1 | 35.0 | 14.5 | 11.0 |
| October | 29.0 | 37.1 | 17.0 | 12.0 |
| November | 32.7 | 40.0 | 19.7 | 13.5 |
| December | 31.1 | 40.5 | 19.0 | 13.0 |
The vegetation of this landscape has a strong relationship to that of the Acacia welwitschii-thickets. It seems as if Acacia welwitschii moved into the same habitat as Colophospermum mopane as the climate became wetter. Both landscapes are unique to South Africa and deserve special priority in conservation.
Fauna
The thick mopane forest is ideal habitat for elephant breeding herds. Buffalo and impala are commonly found. Rare species of game such as nyala and Sharpe’s grysbok (Raphicerus sharpie colonicus) are fairly common in this landscape. Kudu bushbuck and duiker prefer the dense bush. Steenbok occur less frequently in this area.
