He climate change and rural abandonment have turned our mountains into powder kegs and, when a large forest fire breaks out, the problem is not only the ecological devastation, but the immense column of toxic smoke that suffocates populations located hundreds of kilometers away, as we have suffered in Spain in recent years. Faced with this scenario, researchers defend a tool that may seem quite strange to other eyes: burning the forest on purpose to create firebreaks.
It is validated. A new study published in Science has put on the table the evidence that supports this practice known as prescribed burning. One of the data they collect is that carrying out low severity fires generates an immediate 92% reduction in the probability of very high severity fires occurring in that same place.
Far from being a temporary patch, researchers have proven that this “vaccine effect” lasts up to 10 years and extends its protection radius up to 5 kilometers beyond the treated area.
The air. One of the perhaps most important findings of the research lies in the air we breathe, since fine particles emitted by large forest fires are a serious risk to our lungs. But with this method, researchers calculate that, in the case of California, burning 500,000 acres a year can reduce the accumulated pollution of these microparticles in the air by approximately 10%.
How it works. Víctor Resco de Dios, professor of Forestry Engineering and Global Change at the University of Lleida, sums it up clearly: “The fumes from prescribed burning are much smaller than those from fires.”
And the key is in the continuity of the fuel, since when a forest fire that advances without control collides with an area that has been previously treated with controlled fires, its intensity plummets. The fire moves from the treetops to the ground, offering firefighting teams a vital window of opportunity to extinguish it, radically reducing the total smoke emission.
In Spain. Scientific rigor requires reading the fine print, and in this case, the geographical context is decisive. The overwhelming data that we have collected comes from the analysis of the coniferous forests of California and as the expert Víctor Fernández García points out for SMC“California is not Spain.”
While in the western United States or in the oak forests of Mexico, prescribed burning can be considered at a landscape scale, in Spain its use is currently “very specific” and localized. This is because in our country short and medium term burning requires surgical precision because there are native species such as the Pinus nigra or the Pinus pinaster which are very resistant to fire.
But it is useful. This same expert, speaking to SMC, points out that in Spain, after several decades of rural abandonment, “we have accumulated fuel and increased the probability of extreme fires.” That is why, although we are not like California, it does offer a useful warning about these types of practices such as low-risk fire grazing or controlled burns.
Images | Michael Held
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