is often called the "continent of fire". It
is estimated that of the 750 million hectares of vegetation
burnt yearly, nearly half occur in Africa. Globally,
the most affected areas are East Africa, Central Africa
and Southern Africa.
Although wildfires are happening
throughout the year in Africa, over 90% of fires occur
during the dry season. Dead or dormant vegetation
and trees that lost their leaves produce an accumulation
of combustible materials on the ground.
These fires may be accidental,
but more often they are triggered by people voluntarily.
Fire is indeed traditionally used as a tool for land
management. For agricultural land, fires are used
to clear and remove dried residue. For grazing, fire
is the main agent of decomposition that allows the
return of nitrates in the soil while maintaining high
productivity of the land. Fires are also used to guide
the game or to reduce the risk of unplanned fires.
The fires, even voluntarily
induced, are not always controllable. They can spread
rapidly and cover large areas. The abundance of dry
vegetation, low population density and lack of areas
that can act as a firewall are all reasons why the
fires easily spread.
The fires can therefore cause
extensive damage and even loss of life. They also
have a major impact on global change, as they are
responsible for significant emissions of greenhouse
gases and aerosols. Savannah and forest fires release
nearly 3.5 billion tons of CO2 and 17.5 million tons
of particles, corresponding respectively to 42% and
49% of emissions from fires in the world.
These reasons justify the
increasing interest in the study of wildfires. Today,
remote sensing appears to be a valuable tool for monitoring
fires and for the objective assessment of their emissions.