2. AFOMONOTANE FOREST

Synonyms:

Knysna Forest (A4), North-eastern Mountain Sourveld (A8), Highland & Dohne Sourveld (A44a & b); Montane Forest.

Statistics:

5964 km²; ± 44% transformed; 17.64% conserved.

Locality & Physical Geography:

Patches of forest with Afromontane floristic affinities occur all along the mountain chains (altitudes from sea level up to 1 500 m) from Northern Province through Swaziland (not mapped) and KwaZulu-Natal to Western Cape. In the latter they occur on south-facing ridges and in ravines where moisture is higher and the maximum effect of the south-westerly and south-easterly wind-driven rains is apparent. Forests of these regions range from small to extensive patches on mountain-sides depending on locality and variation in aspect, geology and soils. Afromontane Forest reaches its greatest stature in the Tsitsikamma region from where it extends to Knysna.

Climate:

Rainfall is generally greater than 700 mm per year, and can exceed 2 000 mm in some regions, occurring throughout the year, or during winter or summer, depending on the region. Temperatures can be extreme in some of the higher altitudes where snowfalls may occasionally occur.

Geology & Soil:

Soils are generally well-developed and mature, and, in the higher-rainfall regions, may be leached. They tend to be shallow on steeper slopes, but may be fairly deep in valleys.

Vegetation:

Floristically the Afromontane element is dominant, but Pondoland-Tongaland forest species may be common in Eastern Cape and KwaZuiu-Natal. Thus, although Afromontane Forests are greatest in stature in the Knysna region, there is a greater diversity of plant species in the Amatole Mountains of Eastern Cape where more PondolandTongaland species are present. Trees can be up to 30 m or 40 m tall and distinct strata of emergent trees, canopy trees and shrub and herb layers are present. Tree species include: Real Yeilowwood Podocarpus latifolius, Outeniqua Yeilowwood P. falcatus, White Witchhazei Trichocladus ellipticus, Rhus chirendensis, Curtisia dentata, Calodendrum capense, Apodytes dimidiata, Halleria lucida, llex mitis, Kiggelaria africana, Nuxia floribunda, Xymalos monospora and Ocotea bullata. Shrubs and climbers are common and include: Common Spikethorn Maytenus heterophylla, Cat-thorn Scutia myrtina, Numnum Carissa bispinosa, Secamone alpinii, Canthium ciliatum, Rhoicissus tridentata, Zanthoxylum capense and Burchellia bubalina. In the undergrowth grasses, herbs and ferns may be locally common: Basketgrass Oplismenus hirtellus, Bushman Grass Stipa dregeana var. elongata, Pigs-ears Centella asiatica, Cyperus albostriatus, Polypodium polypodioides, Polystichum tuctuosum, Streptocarpus rexii and Plectranthus spp. Ferns, shrubs and small trees such as Cape Beech Rapanea melanophloeos are often abundant along the forest edges.

Key Environmental Parameters:

As is evident from the way the forest is confined to kloofs and gullies, water is a key limiting factor. However, Afromontane Forest would certainly spread into both grasslands and Fynbos were it not for fires - all forest patches are in fire-safe habitats with the largest stands occurring in the moist valleys of the Garden Route where they are protected by the sea and the Cape Fold Belt mountains.

Economic Uses:

Forest trees are continually exploited for timber although specific species are usually selected. Likewise, other species are selected for muti and, in the more populated areas, for firewood.

Conservation Status:

Afromontane Forest is well conserved in a number of areas, and many stands are safe from exploitation by their isolation in remote areas. Plantations of pine threaten the water supply to the indigenous forests in many regions.

Key References:

Moll (1972), White (1983), Lubke et al. (1988).

Authors:

Roy Lubke & Bruce McKenzie.