A wildfire behaves according to the environment in which it is burning, with several factors being responsible altogether for its evolution and intensity. Parameters involved in wildfire behaviour can be categorized in three different groups: they can be related to fuels, to weather or to topography. Just like the fire triangle (see web article 2), we could picture the fire behaviour triangle with these three main categories in each side (figure 1). As you may imagine there are many variables under these three major fire environment components. Regarding weather, we could talk about the effect of wind pushing flames forward, the role of temperature and relative humidity on the state of the vegetation or about (the lack of) precipitation on soil and fuel moisture. Concerning fuels, we could also list a large number of parameters (load, arrangement and continuity, composition, bulk density, moisture, etc.) that play a key role on fire behaviour. Finally, regarding topography, we could mention aspect or slope as very important factors on fire propagation. We cannot discuss in here how all these parameters interact and affect fire behaviour, but, for those interested on receiving a quick master class on that, do not hesitate to watch this great lesson from University of California experts!
A change in any of these environmental parameters will cause a change in the behaviour of the fire, and this change can be either to reduce wildfire spread and intensity or to dangerously increase it. It turns out that the only type of variables that can be managed so that to reduce fire hazard in a particular site before a fire event takes place are obviously those variables related to fuels, as climate and topography cannot be modified by any means! And this is what fuel management consists of: fuel management comprises the implementation of particular treatments to fuels in wildland areas so that to modify potential fire behaviour or fire effects with the final aim of reducing risks to human communities and improve ecosystems’ health. As stated by fire management experts from Southern California, by treating fuels in the present we have the opportunity to determine how the fire will behave in the future!
Fuel management is important simply because it gives us the opportunity to modify the pattern of future fire by modification of today’s fuel
(Sue Husari, Thomas Nichols, Neil G. Sugihara adnd Scott L. Stephens in “Fire and Fuel Management” (Fire in California’s Ecosystems)