WHY DO WE HAVE SO MANY FOREST FIRES?

by Whit Gibbons

October 23, 2016

Question: What fire in the Midwest killed more than a thousand people on Oct. 8, 1871? (Hint: It was not the Great Chicago Fire.).

Answer: The Peshtigo Fire in Wisconsin.

Estimates for the death toll from the Peshtigo forest fire range from 1,500 to 2,500. At the site of the former town, a mass grave holds the remains of up to 500 unidentified victims. The death toll for the Chicago fire was estimated to be 250 to 300 people.

So, why is the Great Chicago Fire better known than the far more deadly Peshtigo Fire 225 miles due north? Economics. Almost $200 million, a whole lot of money back then, was estimated to have been lost in the city fire. Mostly cut-over woodlands were burned in Wisconsin, except for the hundreds of people trapped by the fast-moving forest fire. Forest fires have traditionally been classified as disasters when economic loss occurs. The well-publicized fires on the West Coast qualify because of the loss of merchantable timber and expensive houses.

But what about the effects on wildlife? I know of no native species of plant or animal that has ever gone extinct because of natural fires on any continent. Organisms have adapted to persist with periodic fires in regions where fire is a natural phenomenon, with mortality of native plants and wildlife during fires being negligible. A few terrestrial mammals, amphibians, reptiles and even birds may be killed in forest and prairie fires, but overall levels are seldom affected. Insects and spiders are also susceptible to fires, but recovery to normal population sizes generally occurs within a few months.

Where fires occur frequently from lightning, nature is prepared. The dominant plants are fire-resistant or even fire-dependent. Jack pines in the upper Midwest and wiregrass in longleaf pine forests of the Southeast depend on fires to produce viable seeds. Burning of the litter layer exposes mineral soil, optimizing seed establishment. A side benefit to young longleaf pine and other fire-resistant plants is the return of essential nutrients to the soil. In a region with fire-tolerant vegetation, native animals adapted to living with periodic fire are also resistant.

In presettlement times, fires whooshed through forests frequently enough to prevent heavy buildup of ground litter. Without firefighters or roads to retard their spread, some natural fires covered immense areas, eventually being extinguished by rain or a river barrier.

Little or no flammable material remains after a forest fire. Only a scant covering of dead grass, leaves or pine needles is available as fuel in the years following, resulting in fires that burn rapidly and usually low to the ground. Under such a cycle, fires are part of the natural environment and no more detrimental to wildlife than other natural events. But where forest fires have been suppressed for decades, the buildup of ground litter can be immense and serve as fuel for a hot and prolonged fire. If the fire reaches the tops of tall trees, a crown fire develops, spreading from the top of one tree to another.

Some forestry programs are actually designed to prevent buildup of ground litter. But controlled, or prescribed, burning often results in complaints about smoke on highways and in neighborhoods. Homeowners in those areas need to stop complaining about the smoke when forestry programs want to use controlled burning to clear the forest of potentially dangerous ground litter. Surely a little smoke in the living room for a week is better than having the whole house destroyed when it's engulfed in flames.

As long as we suppress fires and allow forests to build up combustible material, the threat of dangerous forest fires will always be with us. Two attitudes exist about how to deal with such threats: Either change fire suppression policies and avoid out-of-control fires through prescribed burning or maintain a national, ever-ready forest-fire-fighting force at taxpayers' expense and let wildfires keep happening. The first approach seems more reasonable.

If you have an environmental question or comment, email

(Back to Ecoviews)

 

 
SREL HomeUGA Home SREL Home UGA Home