FUELLING MEGA FIRES
LACK OF LAND MANAGEMENT MAKES IBERIAN PENINSULA RIPE FOR MASSIVE EVENTS
BY LILY MAYERS
As the incidence of mega fires intensifies across the Iberian Peninsula and around the world, experts in fire operations and research say it’s critical to acknowledge the precursors of extreme wildland fires and understand what fuels the severity and scale of these large phenomena.
Fierce and erratic mega fires have become a staple chapter in southern European summers.
Lacking international consensus on the specifications of mega fires, an accepted definition is fires that burn an area of more than 5,000 hectares or emit more than 10,000 kilowatts of energy per square meter.
What sparks a mega fire is not what determines its behavior, size, or its speed, nor does understanding how a fire started hold the solution to preventing future catastrophic wildfires.
Three critical variables fuel mega fires: uninterrupted expanses of forest; dense, flammable overgrowth; and the convergence of unstable atmospheric and climate conditions. The catalysts – continuity, density and weather – mean the difference between a fire burning out, and one capable of generating enough momentum to surge across the line of control.
Mega fires have been recorded as far back as 350 million years ago but due to dramatic shifts in land use and with the accelerant of climate change, they are becoming more frequent, more destructive and affecting new geographic regions. In 2023 Greece experienced the worst fires in European record with more than 94,000 hectares of land burned in a single event and at least 28 people killed. The deadly Hawaii firestorm in Maui killed more than 100 people and decimated the town. Dwarfing all other countries in 2023 was Canada, where more than 15 million hectares burned – more than double the 1995 record.
The effects of these devastating mega fires are something fire-prone Spain and Portugal understand intimately. In the last 17 years, the countries have cumulatively burned more than 3.1 million hectares of land to wildfires.
CONTINUITY
Experts agree one of the most significant causes of mega fires is the expanding continuity of global forests. In the context of mega fire danger, unmanaged and abundant tree areas are an enemy hiding in plain sight.
Spain’s treeline has exploded in growth over the last 30 years while Portugal’s has declined. After huge treeline increases in the second half of the twentieth century, experts say Portugal’s forest recovery was delayed by land-use changes together with several fire events after the 1990s that severely scarred the country.
“Contrarily to other European countries and especially Spain, [in Portugal] we don’t see this expansion of forests, what we see clearly is more the loss of agriculture in between forests and shrubland patches, which again reinforce the propensity to have increasingly larger fires,” said Paulo Fernandes, forestry engineer and senior researcher at Portugal’s University of Trás-os-Montes and Alto Douro. But even with the losses and slow regeneration, the country now has more trees than it can manage.
“The last time we had so many forests was by the beginning of the neolithic,” Fernandes said.
As of 2021, about 56 per cent of Spain’s land was covered by forest ecosystems and every year that number grows. To reduce fire risk, experts say the country actually needs fewer trees and shrubs.
Forest continuity is predominantly the fruition of neglected land. After managing and using most of Spain’s forests for thousands of years, the abandonment of agricultural lands and rural towns throughout the mid-20th century facilitated an unfettered expansion of trees. As farming families sought greater employment opportunities with increasing industry in capital cities, trees and shrubs enveloped their fields, blurring parcels of cultivated land into homogenous forests. This relentless reclamation of nature has resulted in expansive forest spaces as well as two of the largest demographic deserts in Europe known as the Spanish Lapland and the Celtic Strip.
Without interruptions in forest continuity in the form of heterogeneous mosaic landscapes, clearings and agriculture, fires can spread indiscriminately. One of the Peninsula’s most critical cases of fuel continuity is in the lower Pyrenees. Forests cover 59 per cent of the mesic mountain range, according to the Pyrenean Climate Change Observatory, with the most uninterrupted expanses in the central eastern regions. Carbon studies have traced the mountain’s coniferous pine forests back between 50,000 and 15,000 years. In the past century, however, this resilient forest’s treeline has bulked up and crept to higher altitudes.
Like most forest environments across the Iberian Peninsula, the Pyrenean landscape has undergone multiple land management changes throughout the nineteenth and twentieth centuries.
“All forests are an expression of our social and natural history,” said Marti Boada, a professor, geographer, and author. The 73-year-old Catalan grew up in the prePyrenees and has dedicated his life to understanding forests across the Peninsula and the world. Along with his exhaustive research, Boada has witnessed firsthand the changes Spain’s forests.
“The biggest change is the energy change, when hydrocarbons arrived en masse in the 50s or 60s . . . People no longer cooked with charcoal or firewood,” Boada said.
“What was previously about five tonnes per adult per year in forest consumption, is now five butane cylinders; this is key.”
When the forests stopped being utilized, trees reclaimed the space.
The most effective way of seeing the impact a rural exodus has on forest spread is from above.
“In the 60s we in Catalonia had 37 per cent of the surface covered by forest area, and now we are at 72 per cent,” Boada said. That surge in trees has meant a simultaneous increase in the forest’s demand for water.
“If you had about 2,000 trees per hectare and now you have more than 20,000, it is as if you had 10 geraniums in your home and you added 100. And you can see this, that is, the river flows have dropped, the aquifers have dropped also.”
Water stress is one of the leading causes of forest mortality in the Pyrenees, which currently sits at around 38 per cent. And the higher the forest mortality, the higher the mega fire danger.
“With this heat, ignitability can come to you in the most unexpected way,” said Boada, “Not only the prePyrenees but all of the Ebro Valley is going to burn.”
It’s a dark prediction but one echoed by other experts. While fires in the Pyrenees are rare, simulations developed by Catalunya’s forest fire service found if a fire were to start under heightened meteorological conditions, it would have the potential to burn through an enormous amount of land based on the current fuel levels.
“So right now we have three per cent more chances than we used to have in 2015 of having an event that can support a fire spreading for more than half a million hectares in the Pyrenees, even reaching one million hectares,” said Marc Castellnou Ribau, inspector of Catalunya’s internationally recognized Forestry Action Support Group (or GRAF) and a leading expert in fire extinction.
“So that was impossible 10 years ago. It started to be possible but rare in 2015, and now there’s a good chance for that to happen. All the elements are ready to cook the recipe, it is just a question of when.”
An important role in this transformation can be played by pyrocumulus, large clouds originating from the intensity of the flames of a fire and like those generated by volcanic eruptions. The mass of warm air made of water vapor and ash rises at high speed and condenses when it meets a cooler environment. Pyrocumulus can cause thunderstorms and electrical activity; they are capable of generating bursts of rain and spreading small particles of ignited matter, to create new fronts or secondary fires.
If a fire did start in the Pyrenees under high fire danger conditions, the simulations predict it wouldn’t take long to develop into a mega fire. “It needs one day to start and build pyroconvection, one long night where the pyroconvection is maintained and the second day when it finally blows up. That’s the process,”said Castellno. “There is a lot of evidence of mountain areas around the world going through the same process and the Pyrenees are no different.”
The region has become Castellnou’s team’s most critical focus area. “It is where the big fire can happen and where the most efforts to convince society that we must manage the landscape is.”
Graciela Gil-Romera, an expert in fire paleoecology at the Pyrenean Institute of Ecology, a research center within the Spanish National Research Council, agrees the current forest spread in the Pyrenees creates a very dangerous situation.
“Having such continuity of fuel in the scenario of global warming, that’s a bomb,” Gil-Romera said, “Sometimes you have the urban forest boundary mixing with the wilderness and that’s when the critical thing happens. Because then you may have a fire start which might not be intentional and then it spreads with no end, and there’s nothing, no means that can stop the fire.”
Wedged in by this prospective fire fuel are the small rural towns and urbanizations dotted across the mountain range; residents will find themselves in the eye of the storm should a mega fire ignite, something that deeply concerns Castellnou, who sees new homes continually built in the path of future fires.
“The population is living calmly on a Mediterranean coast or in a boreal forest because they think a devastating fire cannot happen because the extinction systems have been saying they can put out the fires,” said Castellnou. “But we are not explaining the whole truth. We can no longer put out those fires. We are not prepared [for mega fires], although we have been warned.”
Wrangling continuity is an endless battle against nature’s unrelenting growth but it is also a result of fast and effective firefighting operations. This concept is known as the fire paradox because the success and efficiency of extinction operations over decades has directly contributed to an increase in the fuel continuity and therefore fire danger.
Unlike surface level prescribed burns or small grass fires, mega fires damage plant tissue and cause long-term scarring, delaying landscape recovery. This paradox has led to calls for a shift in focus from solely reactive extinction operations to proactive fuel management.
“We need to think that fire is part of our ecosystems in the Mediterranean forests,” said Sergio de Miguel, associate professor of the University of Lleida and researcher of global forest ecosystems. “We have to live with fires and we can, through management, decide how they occur,”.
If this change were realized it would also be a significant cost-saving measure. “Why? Because we respond, not to what is burning but to what could burn,” said Castellnou. He says current firefighting operations cost about 20,000 euros per hectare, while the average cost of managing a hectare of land is between 2,000 and 3,000 euros.
DENSITY
Knotted within the forest walls is the second variable fuelling mega fires: density – the vertical and horizontal build-up of vegetation undergrowth which acts as a ladder during a fire, capable of distributing fire to other trees and rapidly lifting flames from the forest floor up to the canopy. A forest’s mass of ladder fuels will determine how hot a fire burns and how fast it travels. To get a rough idea of how dangerous the fuel load of an area is, forest engineers use a simple rule of thumb simple formula: If a square meter of land holds more than a kilogram of dry litter or shrub, that indicates it could burn at 10,000 kilowatts per meter, equivalent to the magnitude of a fire that cannot be successfully fought.
At its heart, forest density is an absence or failure of fuel management. Throughout the Iberian Peninsula there are extensive areas of high vegetation density. Portugal’s central region is the country’s most dense, and an example of how good and bad forest management can affect fire behavior.
“That’s the big problem with these large, very continuous, very dense forest patches that are so characteristic of central Portugal,” said Fernandes. “It began by being planted, supposedly it would have to be managed in an orderly manner, but it has become a certain jungle, so to speak, of trees of various sizes and heights, but always in great density and therefore enhancing extremely intense fires.”
Fernandes believes the region suffers under the weight of so much forest mass mostly due to a lack of clearing by small private landowners.
“The soils are not at all good for agriculture and the use of forestry from the mid-twentieth century became . . . the obvious option or the only option in terms of economic income for the population. The entire area was initially forested with pine and later with eucalyptus. The problem is that in these plantations, especially after fires, the intensity of the management is generally very reduced.”
Portugal is ranked seventh in the top 10 countries with the highest proportion of forests under private ownership, accounting for 95 to 97 per cent of the territory’s total forest area (much like the neighboring Spanish province of Galicia.) Most of these properties cover less than 0.5 hectares of land however many owners are still unable physically or economically to actively manage their fuels.
“There is no forest management, and in many situations, there is no professional management,” Fernandez said. “When there is some, it is in forests managed by companies. These types of forests or plantations are inherently vulnerable to fire due to the accumulation of biomass by the species that are used, which are normally fast growing like pines or really fast like eucalyptus.”
In Spain similar examples of worrying forest density can be found. In the province of Extremadura many farms and olive groves have been left abandoned due to a drop in profitability and the toll of labor. Jesús Campo García is among those who have walked away from their plots. The 72-year-old has spent his life in and around Monfragüe National Park in the municipality of Serradilla working as both a forest agent and an olive farmer.
“There is nothing managed here in La Solana other than a few farms right next to the road, they are the only ones. Everything else is completely lost, everything,” he said. During Garcia’s 25 years working as a local forest agent, he witnessed the landscape change, the shrubs build up and the fires intensify.
Aiding in the crowding of forests has been the gradual tightening of important conservation regulations on natural spaces, especially in Spain. The environmental protections needed to preserve biodiversity and habitats have been strengthening since the second half of the twentieth century. In Portugal, 22.4 per cent of the land is defined as protected areas and in Spain 28 per cent. Many protected areas form part of a chain of European forests known as the Natura 2000 Network and their protections mean that to preserve the native plants and wildlife, limitations are enforced on the ability to manage the fuel buildup, carve fire breaks, and perform prescribed burns. That’s why in some parts of the Peninsula, largely in Spain, experts are concerned the restrictions risk endangering the subjects they were created to protect.
In the 2022 fire season, 42 per cent of the total razed land in Spain was within Natura 2000 sites, with the Sierra de la Culebra in Zamora, Alto Palancia in Bejis, and Serra do Courel in Galicia the worst affected. In Portugal, 37 per cent of the fires were in protected Natura 2000 sites, with the worst affected in the Serra da Estrela Nature Park and the Alvão Natural Park. This follows a trend in recent years where protected areas appear to be having an increasing vulnerability to fires. In Portugal protected areas pose less of a problem, due to more relaxed clearing policies allowing an easier balance between nature and people.
In Spain, fires within the Natura 2000 Network have been found to be on average twice as destructive as those originating outside, according to the Spanish Government’s Los incendios en la Red Natura 2000 report. “There are two take-home messages here,” said scientist and forest engineer Victor Resco de Dios of the of the University of Lleida, who co-authored a study into the drivers of the 2022 fires. “One is that protected areas are not protected against fire, they do burn, so fire prevention must happen there and in some areas, we see protected areas burning more than they should based on the area they occupy.”
WEATHER
Some of the most significant precursors to mega fires are impossible to see but essential to understand; humidity, wind and increasing temperatures are among them.
The relationship between vegetation and its access to water, both through the earth and the atmosphere, directly influences flammability and therefore mega fire risk at all times. When temperatures are high and relative humidity is low, plants want to retain as much water as possible, so they must choose between growing or surviving. In either case, plants are left with a lower moisture content and as a result burn faster.
Researcher Javier Madrigal from the Forest Fire Laboratory of INIA-CSIC in Madrid says a plant’s flammability is partly determined by its characteristics, such as thickness, however, it will mostly be influenced by the amount of water inside it. “That doesn’t mean to say that a wet tree does not burn, because if there is a lot of energy everything will be lost, but it gives us an idea of the ease with which one process can occur with respect to another.”
Dry weather and a lack of rainfall translates to drought. The Iberian Peninsula periodically experiences long stretches without sufficient rainfall. For Spain, the drought of 2019 to 2023 could have a lasting effect on mega fire danger.
“All climate models say that it will last for decades because it is not only a temporary drought, but a global circulation change, so we will see a total change of our landscape in the coming decades because we are changing the water regime,” said Castellnou.
Dry lightning storms seize the parched and dead fuels. Fires started by lightning account for only a small percentage of total fires in Spain and Portugal but they are increasing in frequency and burning larger areas of land, presumably because they can ignite during a moment of heightened atmospheric instability, often in densely forested areas away from high surveillance and are capable of igniting multiple fires simultaneously.
“When a fire occurs in those [dry lightning] conditions what it really does in the atmosphere is throw the flame front literally upwards, it draws the flame front towards itself and accelerates the combustion process,” said Madrigal.
Back on land, topography also plays a big role in determining mega fire direction and intensity. If an area is inaccessible to people or machines, not only will the fuel be unmanaged but when a fire starts it can’t be controlled. The formation of the land itself also has the potential to shape the fire’s progression, influencing direction through the aspect and degree of slope and the creation of wind channels.
Accelerating and exacerbating these factors is climate change. Not only does human-caused climate change lengthen the fire season, it also increases the frequency and intensity of mega fires. Tiago Oliveria, president of the Portuguese Agency for the Integrated Management of Rural Fires (AGIF), describes the challenge as one without a hero.
“Do you know any hero the world recognized because he prevented an event that didn’t occur? It’s not popular, so we are facing a dilemma here. We know how to do it, [prevent fires], the money is flowing in the proper direction, but we are not doing it as fast as it is needed.
“There is a joke people who work in these types of phenomena use. It’s that a guy is jumping from the tenth floor and he is skydiving to the ground and on the second floor, he says, “So far, so good.” It’s a dark joke but it describes a little bit of what we are envisioning. If you don’t treat the vegetation, the only solution you have on that critical day, it’s evacuation. You cannot fight that fire unless you have fuel management.”
This article was developed with the support of Journalismfund Europe.
Lily Mayers is a cross-platform freelance journalist from Sydney, Australia, based in Madrid, Spain. Mayers’ career began in television and radio news for Australia’s national broadcaster, the ABC. Since moving to Spain in 2020, Mayers’ work has focused on the long-form coverage of world news and current affairs.
