Asturias has been appearing for decades, along with Galicia and Cantabria, among the Spanish territories that accumulate the highest number of forest fires and the largest area of forest burned annually. As we have been suffering for weeks, these fires appear in waves at the end of autumn and winter, coinciding with events of mild temperatures and a strong south wind.
From an ecological scientific perspective, this situation is, to say the least, paradoxical, since it is a region with a temperate oceanic climate with abundant rainfall and mild temperatures. Here, what is expected is a very low frequency of low intensity fires, caused by lightning storms. How is this situation possible then?
daniel garcia, Author provided (do not reuse)
Climate change and fires
It can be argued that the cause is global climate change, which brings warming – an increase in average temperature – and an increase in the frequency of extreme weather events (for example, major electrical storms). This causal association between climate change and fires is almost a textbook headline in the local press.
However, heating itself is not a direct cause of fires, especially in the fall and winter. The burning bush, which combusts spontaneously, is an effective biblical metaphor but it is not a physical reality. It is true that warming decreases the humidity of the vegetation, increasing the probability that, for example, a lightning strike will lead to a fire, and also that this fire will later have greater intensity and extension. But, strictly speaking, heat does not cause fires. On the other hand, there is also no clear evidence that the frequency and magnitude of electrical storms is increasing in Asturias due to climate change.
burn? Or do they burn it?
Discarding the weather as a relevant mechanism, we only have human action as the main cause of the fires. In fact, practically all winter fires in Asturias are caused, accidentally or deliberately, by people. The so-called culture of fire underlies the deliberate causes, which would encourage the burning of woody vegetation (shrubs and forests) as a measure of agricultural and livestock management.
Traditional rural knowledge considers fire as a tool to maintain and improve livestock production, by opening space for meadows with higher nutritional quality grass for livestock.
This traditional belief generates a social background that encourages the use of fire as the only effective way to “clean the bush.” Thus, the removal of woody vegetation is justified to obtain pasture, clear roads and agricultural stands, or simply to maintain a cultural landscape dominated by open spaces.
Unfortunately, the massive waves of fires suppose an overflow of the culture of fire to enter, with additional motivations of social discontent, in vandalism.
Under a traditional use scheme, it is assumed in a paradigmatic way that fire increases extensive livestock profitability. However, empirical evidence that this paradigm works on a large spatial scale is scant. It is considered that fire improves the pasture when it affects small and gently sloping surfaces, and when controlled and rotating grazing is encouraged after the fire with animals that, like goats, feed by browsing the regrowth of bushes that have a high capacity. to recover quickly after the fire. This control of the scrub would allow the expansion of diverse and nutrient-rich herbs, which can be used by cattle with a more selective diet, such as cattle.
This is the theory. In practice, agricultural conditions in Asturias are far from being adequate for a supposed fire-livestock profitability binomial.
Thus, the regional herd is dominated by cows, ineffective in appeasing the regrowth of the burnt scrub, and whose herds move little and tend to concentrate in reduced extensions of the forest (the so-called ports).
The paradoxical result is that, under the current model of extensive livestock use, fire is the scrub’s best ally.
daniel garcia, Author provided
The environmental impact of the fires
Any agronomic or social evaluation of the fires in Asturias must take into account the balance between the possible benefits and environmental damage.
Waves of fires like the one experienced in Asturias this March are a true ecological disaster.
In the Cantabrian mountain environment, these high frequencies and extensions of fire lead to the loss of biodiversity because, as occurs in other temperate environments, many species hardly have the capacity to deal with fire.
We should not apply here the schemes of Mediterranean ecosystems, where vegetation has evolved in an environment of frequent fire that selects traits to resist fire or recover from it (such as having seeds that withstand high temperatures, or showing a great capacity for regrowth). ).
The consequence of the loss of vegetation after fires is the removal of mineral nutrients from the soil by runoff water, an especially intense effect in areas with steep slopes and frequent rainfall. This is precisely how the Asturian mountains are. This washing and the alteration of the soil structure after recurrent fires encourage erosion.
In addition, the combustion and smoke from fires are an important source of emission of polluting particles that are harmful to health and of CO₂ that contributes to the greenhouse effect.
Said release of carbon is especially burdensome if we take into account that, due to climate, soil type and biological characteristics, the forests and scrublands of Asturias are among the ecosystems with the greatest potential to accumulate carbon in Spain, both in biomass and in volume. floor.
Finally, it is necessary to take into account that, just as rural society culturally values the spaces opened up by fire, another large part of Asturian society values positively the contributions that forests and bushes make to human well-being in multiple ways.
Worth?
In view of the above, the fires in Asturias contribute little and harm a lot. We should then urgently consider how to avoid them.
Solving this problem requires, apart from prosecuting and penalizing crimes, convincing those who light the fire that it is not worth it. This is a job for the entire Asturian society that, for this, needs a basic knowledge of the causes and environmental and social circumstances of fires.
