Marloth Park Management Plan. - Nkomazi Local Municipality
Marloth Park Management Plan. - Nkomazi Local Municipality
Marloth Park Management Plan. - Nkomazi Local Municipality
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Bush control<br />
Causes for bush encroachment are manifold. One cause is the misuse of fire. Drought and<br />
human disturbance together with the absence of game migration and the absence of tree<br />
damage by animals, such as elephant, are more likely to cause bush encroachment. The most<br />
important reason for bush encroached areas in southern Africa, is the imbalance in stocking of<br />
the different feeding groups. High stocking rates of grazers, and low stocking rates of<br />
browsers, results in over-utilisation of the grass sward.<br />
With high stocking rates of browsers, young woody plant seedlings cannot develop into<br />
mature shrubs and trees, due to severe over-utilisation. Too low stocking rates of browsers<br />
will result in an abundance of trees and shrubs that will eventually reach densities that<br />
suppress the maintenance and/or development of the grass stratum. Passive management<br />
alone, such as the introduction of large browsers like elephant Loxodonta africana and black<br />
rhinoceros Diceros bicornis can be considered, but does not seem sufficient in correcting<br />
these imbalances. Furthermore, the introduction of these animals is limited to larger<br />
conservations areas only. Correcting these historic imbalances, usually attributed to cattle<br />
ranching, cannot effectively be corrected by adjusting the stocking rates, and active<br />
management will be required. Manipulation of the browser population is considered a tool for<br />
long-term bush control.<br />
Fire as a means of active bush control is of questionable use. Furthermore, the use of fire is<br />
not advised in sweet veld areas, and other measures need to be taken. Mechanical methods<br />
such as clearing bush with chains or bulldozers are effective but cost inhibitive. Even more of<br />
a disadvantage with this method of bush clearing is the soil compaction and disturbance of the<br />
grass layer. Where the grass layer is already decimated, this method is not recommended.<br />
Another mechanical method is ring-barking or girdling. This method causes death of trees<br />
within 1 to 3 years through removal of the bark around the trunk. Chemical treatment of the<br />
exposed trunk area enhances the process and inhibits coppicing. This method is not feasible<br />
for multi-stemmed tree species.<br />
Alternatively, the manual slashing, felling and chopping down of trees is the only mechanical<br />
means of removing encroaching woody plants. Serviceable tools are an axe, a hand-held or<br />
tractor driven chainsaw, a circular saw or a brush cutter. With a tractor driven circular chain<br />
saw up to 2.4 ha can be cleared in one day. Mechanical bush clearing is best combined with<br />
chemical treatment, in this case stump treatment with an herbicide. Stem notching and<br />
application of an herbicide is not feasible with multi-stemmed trees.<br />
© Ecological Associates/ <strong>Marloth</strong> <strong>Park</strong> 97