Kruger National Park (north)

Bushfires are very common in African savannas, especially during the dry season between May and October. Fires in Kruger are managed using the patch mosaic fire philosophy whereby fires are ignited at selected localities and left to burn creating a natural patch mosaic of burnt and unburned patches. These patch fires, although randomly ignited, are closely monitored by the section rangers and only ignited under favourable conditions. This generally prevent the hot, high intensity uncontrolled fires from becoming unmanageable later in the season.
Once the rainy season starts lightning fires may occur and such fires are allowed to burn freely to allow lightning a chance to contribute as one of the natural sources of fire.
During a fire, the grass layer is often burnt completely. However, only the dead leaves are burnt, whilst the roots are still healthy. The early burns may sometimes resprout and this green flush during the dry season will benefit certain antelope species.
Animals can hear, feel and smell a fire when it is still very far away and most mammals normally have enough time to escape. Snakes and many kinds of insects, escape into holes in the ground, where they are safe, because the heat from the fire front seldom penetrates the soil below 5 cm depth.

Interesting link:
The official South African website of Kruger National Park