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Trees as protection of stock against extremes in temperature
Afrikaans | Xhosa
Tree planting is an important aspect of the long- and short-term planning of every farming enterprise, especially where stock are farmed. Just consider the detrimental influence of heat as well as of cold on the production of milk and meat, the survival of newly born animals, and the weathering of wool, where no shade shelters have been provided.
Sheep that stand gasping in the summer sun at noon with their heads in each other’s shadow, or animals that stand facing the wind in the cold of winter, are common sights. In both cases the animals lose mass unnecessarily. Planting trees in the pastures can remedy this.
Where winters are exceptionally cold and windy, windbreaks can be planted in the shape of a square, right angle or circle. The ideal shape, however, is that of a kidney. A windbreak offers protection over a distance of about ten times the height of the trees. That is to say that if the windbreak is 20 m tall, for example, it will protect your harvest over the next 200 m distance.
To obtain maximum effectiveness, a thick hedge can be planted on the side opposite to the prevailing cold wind, so those animals can shelter there during extreme weather conditions. The hedges can be planted in front of the trees. These planted shelters can also serve as a source of firewood and timber.
Various factors may be considered in the choice of trees. A number of evergreen species are suitable, for example pine, eucalyptus, casuarina, cedar and cypress trees. Casuarina, pepper, Brazilian pepper and carob trees grow quite quickly and are resistant to drought, frost, termites and brackish soil. The female carob trees bear masses of edible pods and seeds that are very rich in protein and can be given to cattle and sheep as supplementary feed during the summer months. Eucalyptus, pepper and Brazilian pepper trees produce nectar and pollen from which bees can produce honey.
Evergreen trees can be planted together with more widely spaced deciduous trees within the windbreak. Examples are oak trees, American three-thorn, poplar and Mexican hawthorn. American three-thorn is an excellent shade tree and is also resistant to low temperatures, drought and acid and brackish soils. When the pods are milled to make the protein-rich seeds more digestible, they make a high-quality stock feed.
Stock-watering points must be planned together with the planting of trees. At every watering place and in every grazing camp, a minimum of two - or more trees, depending on the number of stock - must be planted to prevent overcrowding of animals under a single tree. Too much manure and urine, together with soil compaction, will cause a single tree to die.
If trees need to be planted in veld where there is no regular supervision, animals can be kept at bay by covering the trees with thorny branches or barbed wire.
Many farmers in areas abounding in shrubs and trees tend to clear new lands completely of vegetation. Farmers take out trees at great expense. Dust storms and wind and water erosion are direct results of this practice. Crops planted on such new lands are often exposed to hot, dry winds. After the crop has been harvested, animals grazing on the stubble have to endure cold and heat without any shelter.
These are only a few examples of the chain reaction in environmental degradation. This can be prevented by selectively leaving either single indigenous trees on the land, or rows of trees, thus providing shade and shelter, and as a stabilising force in the case of strong winds.
Remember the planting or retention of trees on stock and crop farms is a sound farming principle.
S Steyn
ELSENBURG / WESTERN CAPE forestry extension
