Less than 0,5% of South Africa is covered by indigenous forests. Owing to their slow growth and sensitivity to logging, these forests cannot supply the majority of our country's wood requirements. Additional fast-growing trees are planted to cater for the demand for wood products. Commercial forests, or plantations, cover 1,1% of South Africa.
* Pines, originally from the N. Hemisphere, make up 51% of the total commercial afforestation (TCA) in SA and are mainly used for sawlogs, veneer and pulpwood.
* Gum trees from Australia make up 38,9% of the TCA and are used for poles, mining timber, paper pulp and charcoal.
* Black wattle from Tasmania makes up 9,5% of the TCA and is used for tannin, paper pulp, mining timber and charcoal.
* Other trees make up the final 0,6% of the TCA. Only 16% of South Africa, mainly the wetter eastern parts, is climatically suited to afforestation. In many cases the climate is extremely favourable and local pines grow at two to three times the rate of those in Europe or North America, where they originated.
Alien tree species (e.g. pines and gums) used in local afforestation do well in South Africa because they are not attacked by the insect pests and plant diseases which affect the trees in their country of origin. Careful breeding has also improved the growth characteristics of the species used in commercial forestry resulting in higher yields of wood per hectare. Today South Africa exports close to 2 million tonnes of wood and wood products.
The incorporation of trees with crops, a system known as agroforestry, is one method of increasing fuelwood production that is gaining popularity in Third World countries. Trees grown amongst crops supply timber, nuts, fruit, and fodder for cattle. Appropriate species of trees enrich the soil, prevent erosion, retain water, and shield crops from damaging wind and excessive sunlight.
Habitats most severely affected by afforestation include wetlands, grassland, fynbos and indigenous forests. Good management, and planning that takes conservation of natural habitats into consideration, can overcome these problems, some of which are outlined below:
Wetlands: Plantations situated too close to wetlands and perennial streams, or in their catchments, leads to their eventual drying out as trees use large amounts of water. The endangered wattled crane is dependant on wetlands for breeding (see Enviro Facts "Wattled Crane").
Grasslands: These rich communities support a variety of animals, including threatened species such as oribis, Stanley bustards and blue swallows. Afforestation converts grasslands to plantations, and so these animals lose their `home' (see Enviro Facts "Blue Swallow").
Fynbos: this unique habitat of the western Cape is also seriously affected by the invasion of alien trees from plantations (see Enviro Facts "Fynbos").
Indigenous forests: When plantations next to indigenous forests are logged, trees may fall onto the forest margin and damage it. Once damaged, the forest margin can no longer protect the indigenous forest from fire. In addition, logging can destroy the diverse habitat where forest and grassland meet. The forest margin is an important food source for many forest animals, e.g. bushbucks shelter in the forest but feed mainly on the smaller plants in the forest margin.
River catchments: Trees use large amounts of water. Afforestation in water catchments thus reduces runoff and water availability for other uses (see Enviro Facts "River Catchments").
A better approach would be to tackle this problem at its roots: reduce our reliance on fossil fuels and prevent deforestation of our natural forests. Fossil fuel combustion and deforestation together account for the majority of man-made CO2 releases (see Enviro Facts "Global Warming").
* Fifty-one per cent of commercial plantations are found in the former Transvaal and Orange Free State, 38% in KwaZulu/Natal, and 11% in the three Cape provinces combined.
* Plantation forestry started in South Africa in about 1888.
FORESTS AND TREES. F. Von Breytenbach. Government Printer, Pretoria. 1974.
HOW TO GROW YOUR OWN TREES. J.H. Scriba. and H.L. Gerber. Pamphlet 109, Branch Forestry, Dept. of Water Affairs and Forestry, Pretoria. 1973.
TREES IN URBAN AREAS. J. Voslos Jordaan. Pamphlet 108, Dept. Water Affairs and Forestry, Pretoria. 1973.
Forestry Branch, Dept. of Water Affairs and Forestry. Private Bag X313, Pretoria, 0001. Tel. 012-299 91117.
Faculty of Forestry. University of Stellenbosch, Stellenbosch, 7600. Tel. 02231-773318
Saasveld School of Forestry. P/Bag X 6531, George, 6530. Tel. 0441-711011