By Navashni Govender and Lynn Trollope
© © Navashni Govender and Lynn Trollope
Fire is an integral part of the African savanna. Understanding how it works and the effect it has on the veld is vital for any management plan. With this in mind, Kruger National Park is embarking on an ambitious project to understand just how a fire behaves under different conditions and the effects it leaves on the landscape.
Kruger Park fire ecologist, Navashni Govender, will be working in collaboration with the group "Working on Fire", and Prof Winston Trollope, who has had a long history of involvement with fire issues and management in the Kruger National Park. This exciting project is called SavFIRE, which stands for the Savanna Fire Ignition Research Experiment.
The current fire policy in the Kruger National Park is an Integrated Fire Management System which combines veld condition and patch mosaic burning together with the lightning burning system that was in use in the Kruger National Park before 2002. This new policy is aimed at maintaining biodiversity through realistically co-existing with the reality of unplanned burns caused by illegal trans-migrants from neighbouring countries and other causes.
It also allows lightning fires to occur in a controlled way as a means of providing a practical solution to the occurrence of extensive and highly dangerous unplanned wildfires, which are a hazard especially at the end of the dry season. These point ignition fires means that fire is started from a single source and it has been hypothesised that controlled burns applied as point ignitions instead of perimeter ignitions (block burns) will promote biodiversity of the overall ecosystem.
The theory is that point ignitions will result in a greater fire mosaic developing in the areas being burnt because fires take longer to burn and spread, resulting in a greater variation in diurnal (day vs night time) temperature and humidity conditions.
The consequent variations in fire intensity, changes in wind speed and direction will promote a greater mosaic of different types of fires (head, flank and back fires) with different effects on the flora and fauna in the burnt area, creating a patchiness in the landscape which is viewed as promoting biodiversity in the ecosystem.
SavFIRE is aimed at testing this theory that controlled burns applied as point ignitions are indeed promoting biodiversity and also to determine whether point ignitions do in fact result in a greater fire mosaic of different types and intensities of fires compared to areas burnt as perimeter ignitions.
In addition, managers prefer to use perimeter ignitions as these fires are easier to control. Point ignition fires are generally considered more hazardous and difficult to control, so SavFIRE is also aimed at looking at the minimum area required to apply these different fire treatments to get the same patchy effect on the landscape. Controlled burns applied as point ignitions are more dangerous in terms of escaping than perimeter burns.
However, if the same diverse fire mosaic can be developed by applying perimeter ignitions to areas above a certain threshold size, this would be an attractive ignition procedure for situations where the risk of escaped fires is too great. On the ground a host of vegetation surveys, atmospheric conditions and fire behaviour measurements will be recorded during burning of the selected areas.
Weather conditions will be monitored prior to SavFIRE and the Fire Danger Index (FDI), temperature, humidity, wind speeds and weather conditions in general will be monitored on a real time basis through out the SavFIRE experiment. Aerial photography, satellite monitoring and ground based photography will also be used to record fire behaviour and fire effects, to see the patterns and patchiness the fire scar leaves on the landscape.
A pilot study was done in October 2006 in the Mooiplaas area of the Kruger National Park, to test how the different types of ignition worked. Paired areas of 500 to 4000 hectares were burnt using both point and perimeter ignitions. The progress of the fire was monitored by photographs taken at intervals from the air in a spotter plane.
In 2007 the focus of the SavFIRE experiment will be in Pretoriuskop during June and July. Protective firebreaks have already been burnt in March and April. The logistics behind setting up fire experiments on this scale are immense, as are safety considerations and requirements.
" Weather conditions have to be right" says Navashni, "we have to monitor the changes in temperature and wind daily to make sure all the factors are suitable for a successful controlled burn of the block we select for the experiment". Navashni also added that "working with fire on this scale is dangerous and it takes a skilled team to gather the important data while also preventing the fire getting through the firebreaks".
The trained team from the Working on Fire programme provide just this type of logistical support. SavFIRE will be conducted over a four-year period having started in October 2006 with the pilot study and ending in December 2009. Point and perimeter ignitions will be applied to paired areas ranging from 500, 1000, 2000 and 4000 hectares under similar grass and atmospheric conditions.
This fire research project will make a highly significantly practical contribution to fire management in the Kruger National Park in particular, and other conservation areas in Africa in general and provide also a significant scientific contribution to the fire ecology of African savannas.