Experiment Still Lights Scientists’ Fires After 54 Years
by Michele Hofmeyr
Fire is a common feature of our African savannas – smoke and flames being part of what shapes the landscape into the different patterns of grass and trees we see in the veld. The managers of the Kruger National Park (KNP) have used fire as a management tool for many years, but because the two million hectares of the KNP covers so many different and diverse areas, no two fires have the same effect on the plant life.
How fire affects the landscape has intrigued researchers over the years and way back in 1954 a long-term fire experiment was established to see how different applications of fire affects the landscape. Long-term records of fire in savanna ecosystems are rare, so the information collected from these burn plots provides more insight into the effect that fire has on the landscape.
The basic outline of the experiment is a string of seven-hectare plots in different landscapes in the KNP, each being burnt at different times of the year at different intervals and in different seasons. These are referred to by both the KNP scientists and the managers as the Experimental Burn Plots or EBPs.
Keeping this valuable long-term experiment running accurately is the responsibility of Scientific Services fire ecologist, Navashni Govender. In early March the team planned on burning the plots near Skukuza, Satara, Pretoriuskop and Mopani. The grass on the Skukuza plots turned out to be too green and the fire didn't burn very effectively. However, n Satara the fire treatment worked well because of drier conditions and the Pretoriuskop plots burnt well because of lots of dry grass providing good fuel for the fire.
The highly trained and experienced fire team from Scientific Services, including field rangers from the section, know the correct procedures needed to make sure the fires are kept under control and that safety of staff is the highest priority. The team takes wind speed and direction measurements as soon as the they arrive at the burn plot, so they know the prevailing winds and the conditions before they light the fire. The fire is started with a drip torch and burns through the block very quickly. Trained staff are on hand with a water cannon, fire beaters and hoes to make sure the fire does not jump across the boundary of the block. Navashni co-ordinates all the staff, using a two-way radio, to make sure the entire block is burnt, the fire does not escape and that the staff are safe at all times.
The local film crew, Sanhu, (South African Natural History Unit) were on hand to document all the action and to get a film record of the entire procedure from the initial grass samples taken from the plots to the spectacular head fires as the flames take hold of the dry vegetation.