AfriFireNet

                                                                

 

 

 

2006 2010

Savanna Fire Ignition Research Experiment (SavFIRE):

Effects of point versus perimeter ignitions on fire mosaics
in the Kruger National Park

A recent development in the use of fire in large conservation areas like the Kruger National Park, is the belief that controlled burns applied as point ignitions instead of perimeter ignitions (block burns) will promote the biodiversity of the overall ecosystem. This is because it is postulated that point ignitions will result in a greater fire mosaic developing in the areas being burnt because the fires take longer to burn and spread over the affected area. 

This in turn will result in a greater diurnal variation in the temperature and humidity conditions leading to a greater variation in fire intensity and its variable effects on the biotic components of the ecosystem. Diurnal changes in the speed and direction of the wind during the fires will also result in a greater mosaic of different types of fires (head, flank & back fires) with different effects on the flora and fauna in the burnt area thereby also promoting biodiversity in the ecosystem. At this stage all these perceived benefits of controlled burns applied as point ignitions are untested hypotheses and an urgent necessity exists to determine whether they do in fact result in a greater fire mosaic of different types and intensities of fires compared to areas burnt as perimeter ignitions. 

An added factor is that fires ignited as point ignitions are more hazardous and difficult to control compared to perimeter ignitions which are applied to areas with prepared firebreaks or where natural features of the terrain are used as firebreaks. Such a project is aligned with the overall ecological fire objectives of the Kruger National Park research objective hierarchy, specifically addressing the fire sub-objective "To determine whether effects produced by perimeter burns, at the scale of burn-blocks & burn units, differ in ecological and biodiversity outcomes from those produced by point burns". This willingness to cooperate is also based on the belief that such an investigation would promote the improved use of controlled burning in conservation areas. This in turn would assist in the primary objective of promoting biodiversity in the national parks system in South Africa thereby benefiting ecotourism and its positive effects on general poverty relief in the country. 

Arising from the aforementioned motivation for conducting such a trial the specific objectives for the project are:

  • To determine the effects of controlled burns applied as point ignitions versus perimeter ignitions on the resultant fire mosaic in the major savanna landscapes in the Kruger National Park;

  • To determine the effect of size of burn applied as point and perimeter ignitions on the resultant fire mosaic in the major savanna landscapes in the Kruger National Park;

  • To determine whether the fire mosaic resulting from controlled burns applied as point and perimeter ignitions is significantly different in the major savanna landscapes in the Kruger National Park;

  • To determine whether there is a threshold size of burn above which the fire mosaics developed by point and perimeter ignitions are not significantly different.

The hypotheses that will be tested are: 

  • Point Ignitions will result in a greater fire mosaic developing in the areas being burnt than perimeter ignitions because the fires take longer to burn and spread over the affected area;

  • Because fires developing from Point Ignitions will take longer to burn and spread over the affected area they will result in a greater diurnal variation in the temperature and humidity conditions leading to a greater variation in fire intensity and its variable effects on the biotic components of the ecosystem;

  • Because fires developing from Point Ignitions will take longer to burn and spread over the affected area they will result in greater diurnal changes in the speed and direction of the wind during the fires which will result in a greater mosaic of different types of fires (head, flank & back fires) with resultant variable effects on the biotic components of the ecosystem;

  • Above a certain threshold size of burn the resultant fire mosaic developing from point and perimeter ignitions will not be significantly different. This is because the convection columns arising from perimeter ignitions above a certain threshold size, will not be able to coalesce into a single central convection column but will rather fragment into individual fires burning separately similar to those resulting from a point ignition;

 

Project description and scientific background

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