The dry, windy months from August to October are a time of anxiety for thousands of South African farmers. This is the fire season in the country’s summer rainfall areas – when the terrible dangers of runaway blazes are never far away. Yet if fire can be highly destructive and even deadly, it is one of the vital components of the veld, co-evolving with the savannah ecosystem.
The Kruger National Park (KNP) is a natural yet enclosed area, where fire has to be controlled and harnessed to prevent unnecessary damage and bring new growth. “Fire has been used as a means of veld management since the 1950s in the park,” says Nick Zambatis, manager of biodiversity conservation at the KNP. “Grasslands depend on fire for regeneration.”
The park covers almost 2 million hectares and has its own fire protection association, which Zambatis chairs.
This comprises approximately 260 field and section rangers trained in fire management and operating in 22 sections. “Our job is not to prevent fire, but to manage it,” says Zambatis. “There’s no way we can stop fires.” The KNP regularly experiences accidental fires, caused mostly by runaway fires that enter the park from the outside. Other causes are campfires lit by trans-migrants from Mozambique or careless tourists throwing away lit cigarettes. Some fires are also produced naturally by lightning strikes.
According to Danie Pienaar, head of department, scientific services at the KNP, fire is fairly predictable in the park. “It goes hand-in-hand with rain,” he explains. “If we have a lot of rain for two years, there’ll be more grass to burn whenever a fire breaks out. As managers, we know when and where the fires are most likely to occur.”
Pienaar agrees with Zambatis that they are unable to prevent fires in the park. The trick, however, is to ensure that the fires that do occur are not too destructive, by setting low intensity, controlled burns from time to time. If this is not done, a build-up of biomass occurs, and this can lead to particularly hot fires, causing severe damage. According to Pienaar, the park has experienced too many of these in recent years, and ‘cooler’ fires have therefore been introduced as part of a new fire management policy.
Nick Zambatis, manager of biodiversity conservation and fire protection officer at the Kruger National Park.
“We call them cooler fires because they don’t have as much impact on the trees as hot fires,” he explains. The fires are started between March and June, when the grass is still green and contains a fair amount of moisture. This results in a fire that creeps along slowly, burning in patches and leaving the bush mostly unscathed. Hot fires are therefore still required to clear severe bush encroachment.
However, these can cause significant destruction to trees, especially when combined with bark-stripping by elephants,
“On the basalt plains, the elephants de-bark trees, which makes them vulnerable to hot fires,” explains Pienaar. “In addition, smaller trees can get caught in a ‘fire trap’. Most trees take at least 10 years to get to a reasonable height and during this period they are especially vulnerable. The only way to get the trees to regenerate is to use cooler fires and so prevent hot fires from developing.”
According to Zambatis, the new policy divides the park into five large fire management units, determined by mean annual rainfall, historic fire return periods and geology. Unlike the current practice, the new approach specifies areas for annual burning and then leaves the actual amount of burning to the discretion of the various rangers. These rangers work within the limits of the burning quota set for their area and follow ecological and fire safety guidelines, especially when setting a high-intensity fire.
Zone 1, in the higher rainfall areas of the park, is sourveld on granite. According to Zambatis, these areas require regular burning to improve the quality of grazing and some high-intensity fires to combat bush encroachment. In Zone 2, which is savannah on granite, hot fires are required to combat bush encroachment or reduce the risk of large wildfires.
Fire management zones and frequency of burns in the KNP. Courtesy of SANparks
By contrast, the fires in Zone 3, which is savannah on basalt, are believed to be too frequent and intense. The aim is to reduce them, and reverse the trend towards homogenisation of poor quality grazing. “Cool fires should be set in this zone and very hot fires should be avoided altogether,” says Zambatis. The new management system stipulates burning about half the area that would normally be burnt each year.
Zone 4 is savannah on ecca shale and is characterised by a relative lack of fire. The new policy treats it as a no-fire area, allowing it to serve as a natural firebreak between Zones 2 and 3 in the south. Deliberate burning is kept to the minimum and unplanned wildfires are tolerated. Zone 5, which is savannah-riparian, is treated like Zone 4.
“We have a limited number of veld management tools – fire is one,” says Zambatis. “The Kruger isn’t like a livestock farm where we can rotate the animals in camps.” He adds that a number of policies are being revised. One of these is to remove several artificial water points, as experience has shown that animals tend to remain in these areas, causing over-grazing.
“We’d like to keep the Kruger National Park as natural as possible,” concludes Zambatis.