USA — This summer, forest fires swept through parts of Arizona and New Mexico scorching property and vast expanses of ecosystems and resulting in the evacuation of the enormous Los Alamos National Laboratory. Many fear that more extreme weather may mean wild fires will only become more common in coming years. So what can we do about it?
Last week, scientists at the Pacific Wildland Fire Sciences Laboratory in Seattle, Washington, set out to answer that question – and to smoke out some common myths about forest fires, and their control and prevention.
In a discussion at the lab in Seattle’s Fremont neighbourhood, scientists who recently returned from studying the wildfires in Arizona and New Mexico started by clarifying just how common these fires are – and how infrequently they make headlines. In 98 per cent of cases wildfires quietly burn out and go largely unnoticed by the public, said fire and environment researcher David Peterson. Small fires seldom make the news or draw much scientific interest. But it’s these fires that unexpected weather can amplify until they become massive wildfires that need thousands of fire fighters and dozens of air tanker planes to control.
And while there’s no question that wildfire fighters and smoke jumpers make a huge difference in controlling fires, when it comes to actually dousing the flames, the researchers explained that it’s really up to the elements. “Suppressing” a big wildfire – a costly business – is only really effective to guide its path until rain finally snuffs it out. A more effective method for fighting wildfires is to treat fire-prone land before a blaze begins, they argued.
For example, people who live in areas where forest fires are common have figured out the benefits of periodically clearing their land with controlled burns. In rotation, once every other year or so, they burn down the vegetation on the land, and start the season with a fresh planting. This, said Brian Potter, who works on the atmospheric interaction of fire, has come to be accepted scientifically as an effective way of preventing against big wildfire breakouts – if planned and managed correctly.
But controlled burning continues to be a subject of hot debate because it comes at a cost. Smoke from such fires is hard to control, and a fire burning in one location could send its smoke downwind to another location, exposing people to harmful health effects.
The other issue of course is the risk that the fire could get out of hand. The 1980 Mack Lake fire in Michigan, for example, started as a prescribed burn. However, an unexpected turn in weather turned it into a wildfire which spread and claimed several lives. “The first thing it did was burn up the burn boss’s house on the edge of the lake,” Potter said.
“We’ve got past the scientific debate of whether you need to sometimes use fire to control and ecosystem,” Potter, said. “But we’ve not moved past the social debate of when it is acceptable.”
A second major way that land and wooded areas can be maintained is by periodically removing the shrubbery and small plant matter from the base of a wooded forest. “Thinning” the growth in this way, said Morris Johnson, who studies fire ecology, reduces the severity of a forest fire if it were to sweep through the area. Unfortunately, implementing such a strategy would require a shift in the funding and policy focus of current controllers. “The initial cost of removing and thinning is going to be a lot,” Morris conceded. “But it’s cheaper to maintain.”
As to the question of climate change, ongoing research is hinting at a link between hot and dry, and cool and wet spells, with the location and severity of big forest fire breakouts. “I will argue this with a lot of my scientific colleagues till we’re both blue in the face,” Peterson said, “But for the most part I believe that fire is dependent on climate.”
This means that if temperatures get hotter as models estimate, the severity of forest wildfires would increase and the resources dedicated to curbing the damage they cause would swell proportionately. It’s one of the arguments, Peter says, for re-evaluating policy to shift funding and focus towards wildfire prevention: to better equip us to deal with bigger, badder fires of the future.