Our fire connection has always been a complex affair of love-hate.
Fire brings warmth, safety, clean drinking water, and cooked food, and human expansion out of Africa may have been rapidly tracked. But the fire is also an unruly beast, bringing devastation and death threats with it.
Wildfires can be extremely damaging and threaten the safety and property of individuals residing in areas that are prone to fire. For most individuals, it seems apparent that at all expenses wildfires must be avoided and extinguished.
And they are: 98% of all fires in the U.S. are extinguished effectively today. But the more we invest in preventing wildfires, the worse they appear to be getting. Year after year, as well as their magnitude and intensity, the amount of forest fires is growing worldwide.
In fact, since 2000, the six worst fire seasons have all occurred in the last 50 years. This raises a difficult question: are we partially liable for this wider trend in wildfire size and intensity in our effective attempts to control wildfires? And if so, how does it work?
Any climate with comparatively moist winters and lengthy summer droughts will probably be prone to fire. All this winter water fuels the development of plants in the spring, leaving plenty of vegetation that can dry out and become extremely flammable during drought.
The most flammable habitats tend to be grasslands and shrublands:
It meaning fire has likely been an issue since crops first moved to the ground hundreds of millions of years ago. Indeed, in plant genomes dating back as early as 125 million years ago, the effect of fire is obvious.
But, perhaps surprisingly, in particular, fire-prone habitats, evolution has adjusted the crops and animals to deal with the danger–and vibrantly rebound afterward.
Grasslands and shrublands tend to be the most flammable ecosystems, as the stems of the plant are smaller and faster to capture light.
Fires are common in grassland habitats, such as southern African savannahs. But they move rapidly through the grasses, hardly heating the underlying soil. This enables the fire to survive the plant root systems, so the grasses quickly re-spring in burned fields.
The more money we invest in preventing wildfires, the worse animals seem to get:
from insects to birds and mammals, by running, flying or burrowing out of risk, are generally able to survive wildfires as well.
What’s more, so does the wildlife as quickly as the vegetation returns. The smooth, young grass stems attract grazing herbivores from adjacent regions and enable rapid regeneration of the grassland ecosystem.
In reality, by a method known as succession, these grasslands would slowly transform into the forest without fires. Ultimately, trees can outcompete grasses when circumstances are stable, but frequent fires generate an atmosphere where grasses have the upper hand: slow-growing tree saplings are demolished before they can settle.
This may suggest that fires pose a danger to forest ecosystems ‘ very life. But this is not the case: some forests are also being fire-adapted.
Pine trees discovered throughout the western United States and Canada in the Ponderosa woodlands have dense, heat-resistant bark to safeguard living tissues from increasing temperatures inside. They also drop their reduced branches naturally to avoid the canopy from catching fire.
Natural fires run through these forests every 5 to 25 years. Because the flames burn leaf litter and understory crops, stopping forest-floor vegetation from building up, it is essential for the trees they do.
When fires happen in these forests now, they are high-intensity and their flames reach into the canopy:
Because the vegetation is burned while it is still in comparatively tiny amounts, the forest fires themselves are lower. Their comparatively cool, brief flames leave intact the crowns of the bigger trees and survive the forest.
This is a fire regime instance: the frequency and type of fire frequently experienced by a setting.
However, human intervention in the last century has interrupted the Ponderosa pine forests ‘ natural fire system. By grazing livestock, logging timber trees and systematically fighting fires before they can run their course, humans have altered the ecosystem composition and encouraged forest-floor vegetation to build up.
As a result, when fires are now taking place in these forests, they are high-intensity and their flames reach the canopy.
“Livestock grazing, commercial logging, and deliberate fire suppression have turned some regular, low-security fire regimes into rare, high-security fire regimes, such as the ponderosa trees in the interior west,” describes Timothy Ingalsbee, co-director of the Fire Ecology Association in the US.
Some forest ecosystems are tailored to these extreme fires:
High-intensity fires are disastrous in these crowded forests, killing at least 70 percent of trees on their way. “Generally speaking, the plants and animals that inhabit this ecosystem are not well adapted to this fire regime change,” says Ingalsbee. As a consequence, after intense crown fires, they are unable to rebound.
The remaining exposed, bare soil is highly susceptible to erosion, nutrients are washed away and neighboring streams and rivers are blocked.
While crown fires of high intensity in many forests are disastrous, some forest ecosystems are adapted to these extreme fires.
The pine forests of Lodgepole and the California coastal redwood forests are two such instances. Wildfires whip through these forests with exceptionally warm, elevated flames every 80 to 200 years, and very few trees survive.
Wood ash is an excellent fertilizer, providing plants with a wealthy setting to grow in:
But the trees in these forests generate resin-sealed pinecones that can survive extreme temperatures–and open after the fire has fallen.
“Plants have developed various fire-fighting tactics,” states Çağatay Tavşanoğlu, a fire ecologist at Turkey’s Hacettepe University. “One approach is to survive fire as a seed, not as a single crop.” Indeed, a remarkably big amount of crops are using serotiny–fire-triggered germination–to survive in fire-prone settings. “Seeds are protected in closed cones during a fire in the canopy in lodgepole pines, and then spread into the burned soil,” he describes. Wood ash is an excellent fertilizer, providing seeds with a wealthy setting to grow in, and enabling pine trees to blossom quickly after a fire and regenerate the forest for centuries to come.
Also tailored to high-intensity fires in the Australian bush. Because of their hydrophilic features, Eucalyptus trees flourish here.
Eucalyptus trees generate flammable oils in their leaves, promoting fire when they go down to the ground. The bark of the trees peels away in lengthy streamers as quickly as a fire catches, giving more fuel for the flames.
Some crops can survive with subterranean buds that stay protected under the surface of the soil:
The fires burn hotter and reach the canopy, killing nearly all the trees, but leaving the ecosystem open to fresh saplings. Eucalyptus tree seeds are released by burning only from their seed capsules, and they germinate rapidly and flourish in the fire-fertilized soils.
Because Eucalyptus trees actively foster high-intensity fires, few other species can tolerate living close them, in an exceptionally nutrient-rich setting, offering the trees little competition.
Adapted to a comparable fire regime, the Mediterranean maquis shrubland experiences intense fires about once every 20 years. Here, crops like the strawberry tree use protective subterranean buds to protect their seeds from scorching soils.
“Some crops can survive with subterranean buds that stay protected under the surface of the land and then rapidly re-spring after a fire,” Tavşanoğlu suggests.
These examples indicate that intense fire is essential to preserving biodiversity in some areas, although it is damaging:
“Certain habitats, such as lodgepole pine, still operate with rare, high-severity fire within their natural fire regimes,” Ingalsbee describes. “The problem is that many people think high-security fires are scary and’ unnatural,’ so land managers are trying to prevent them.” Intense fire, while destructive, is vital to maintaining biodiversity in some regions We might think that we are protecting ecosystems by controlling intense wildfires in those regions. But paradoxically, we are effectively growing the vulnerability of species such as the western United States ‘ Sequoia tree trees. The human activity allows other species to muscle in and outcompetes these iconic giants by removing the rare but intense fires that these species have adapted to exploit.
Moreover, as species tailored to a low-security fire regime move into these formerly high-security fire regime forests, the ecosystem becomes more susceptible if and when firefighters fail to avoid one of those high-security fires from sweeping through the forest.
Unfortunately, more and more firefighters might be on the losing side.
Climate change is part of the issue here. Global warming will raise air temperatures and boost the frequency of droughts, creating more possibilities to ignite wildfires.
“Increasing temperature in the Mediterranean Basin and decreasing precipitation may result in bigger fires in the coming decades,” claims Tavşanoğlu.
In the US, the cost of suppressing and protecting federal wildfire has trebled since the 1990s:
A latest research discovered that fire seasons worldwide lasted 18 percent longer in 2013 than in 1979, exposing twice as much fire-prone soil to fire circumstances.
Also, attempts to suppress fire in the last century have meant that forests have become unnaturally overgrown and that they contain plenty of lighting just waiting for an excuse to ignite. There has been an increase in the frequency of forest fires in California and Nevada, where the region burned every year now exceeds that before attempts to suppress fire started.
This leaves a hard issue for officials. After centuries of effective suppression of wildfire, we can now expect that when they lastly occur, fires will be much worse.
This is becoming apparent already: as the frequency of wildfires increases, the price of maintaining them at bay is rising. In the US, the cost of suppressing and protecting national wildfire has trebled since the 1990s and now accounts for almost half of the annual budget of the Forest Service.
There’s something that needs to alter.
We need to modify our leadership policies if we are to decrease the danger of catastrophic high-severity fires in ecosystems that are not tailored to this kind of system.
Variety appears to be the key to restoring fire-prone habitats:
There are three primary choices on the table. The first is the least controversial: use machines to clear understory vegetation, dead trees, and non-native crops to avoid future kindling from building up.
The other two alternatives are more controversial: either use periodic controlled burning–or handle natural fires even more controversially, allowing them to run their course.
The least hazardous and politically acceptable approach may be mechanical thinning, but it can also be very expensive. While timber taken from some trees can be used commercially to offset the cost of extraction, it is simply not useful enough in other trees. Mechanical thinning also takes a lot of time. Many ecologists feel it as a sole approach is merely not worth it.
“Of course, the way forward is to use all the available instruments,” tells Ingalsbee. Mechanical thinning may make sense in some circumstances. But more usually, “there is no replacement for fire” for efficient forest management.
New systems that incorporate natural fire, controlled burning, and mechanical thinning are starting to take hold in the US and Australia, but a slow process has been altering the view.
“Some study shows a major change in government attitudes toward accepting prescribed burning,” Ingalsbee claims.
Fire suppression strategies have tended to ruin spotted owl land:
However, while government acceptance of controlled burning systems has increased, they stay skeptical that natural wildfires can be burned. “Unfortunately, only a few leaders comprehend the science of modern fire ecology,” he adds.
Whatever approach you choose, the variety appears to be the key to restoring fire-prone habitats. To contain a mosaic of individual trees, clusters of trees and openings, forests should be thinned and managed. These patches can be arranged to match the landscape’s natural characteristics–for instance, cooler slopes facing north-east generally support more trees than hotter, south-west slopes, and are less susceptible to fire.
We can even generate an essential habitat for rare wildlife and plants by combining the management of an ecosystem with its geographical characteristics.
The spotted owl is indigenous to the western United States ‘ redwood and other hardwood forests. Their natural habitat of thick forest with a heavy canopy can be highly fire-prone, which means that strategies to suppress fire tended to ruin spotted owl land. However, on wetter, cooler slopes, creating thick patches of hardwood forest offers habitat for this endangered bird without causing a severe fire danger.
Over the past few decades, the Western world may have advocated a policy of no-tolerance on forest fires, but individuals have not always been so eager to extinguish fires.
Aboriginal Australians used traditional fire management methods to decrease the intensity of natural forest fires, such as’ early dry season burning.’ However, with the arrival of European colonists in the early 1700s, these practices were discouraged and then mainly forgotten.
For thousands of years, similar traditional practices in fire management have been used to manage wildfire in South Africa and South America. To this day, they remain efficient, leading several scientists to advocate more extensively for their use.
We became detached from the importance of fire in the landscape:
After the Great Idaho fires in 1910, which burned 3 million acres and killed 87 people, wildfire prevention became popular in the United States. They have “attempted to exclude wildfires from the landscape in Europe and North America, and this has had a detrimental effect on ecosystems that have developed with recurrent wildfires,” says Ingalsbee.
What’s more, the fire has influenced our evolutionary history.
A research released in April 2016 indicates that changes in vegetation in Africa, ranging from grassland to wooded, busty vegetation around 3 million years ago, have caused an incidence of