The removal of some or all of the woody plants creates a vacuum that will invariably be re-populated by woody plants, sometimes by more aggressive species. Natural defences against this phenomenon include a healthy and strongly competitive grass layer, and large bushes that are able to suppress the re-establishment and survival of new bush seedlings.
Despite these natural allies in the fight against re-infestation of aggressive woody species, an aftercare programme is absolutely essential to keep a thinned area open. This can be done in several ways such as mechanical slashing of new seedlings, localised (selective) chemical treatments of new growth, or even applying less popular management options such as controlled burning in combination with browsers. An efficient grazing management system that will ensure the maintenance of a healthy grass layer is also essential.
The most important aspect of an aftercare programme is that it should not be viewed as a once-off operation, but should become a permanent component of the day-to-day management of the farm.