smoke fire

Wildfires produce about 5,000 pounds of smoke per acre while controlled burns produce 3,500 pounds per acre.

Bad news: Wildfire smoke contributes to 15,000 premature deaths every year, according to the Environmental Protection Agency.

Worse news: Expect 40,000 premature deaths per year by century’s end thanks to rising temperatures and bigger wildfires.

Wildfire smoke can cause heart attacks, asthma and lung disease, contributing to the toll of cigarettes, auto exhaust and emissions from coal-fired power plants. One study showed a 7 percent increase in heart attacks and a 2 percent increase in emergency room visits when wildfire smoke rolls into populated areas.

So does that mean the Forest Service’s plan to both repeatedly burn a million acres in Rim Country and the White Mountains will take a toll on human health?

When we were young and naive — the Forest Service devoted itself to putting out every single wildfire within 24 hours. In the next century, wildfires plunged and tree densities soared — from 50 per acre to maybe 1,000 per acre. As a result, much worse fires now appear inevitable.

Now that we’re old and stupefied it’s clear the forest will burn — one way or the other. Loggers can take all the big trees and cattle can eat all the grass — but the saplings and tons of downed wood on every acre will burn anyway.

Keep that in mind as we consider what to do about wildfire smoke.

A lot of smoke

The U.S. Forest Service wants to dramatically increase its use of controlled burns and managed fires to reduce the risk of town-destroying fires. The recently released environmental assessment for the second installment of the Four Forest Restoration Initiative (4FRI) proposes treating almost some 1.2 million acres of oak, ponderosa pine and pinyon juniper forests in Rim Country and the White Mountains. Loggers would remove most of the trees between 12 and 18 inches in diameter. But the plan then calls for repeated controlled burns to get rid of the debris left from the thinning projects and decades of built up duff and wood on the ground. Some 63,000 acres would be treated with controlled burns alone.

That’s a lot of smoke.

No doubt about it: Smoke causes health problems — especially for people with underlying heart and lung problems. Studies show a rise in emergency room visits and premature deaths when wildfire smoke blankets areas where people live. That’s why we’re supposed to stay inside or even use masks to filter the invisible soot on heavy smoke days.

But here’s a question: Will controlled burns have less impact on human health than wildfires?

Answer: Wildfires are definitely worse, according to the EIS and multiple studies.

Here’s a related question: Can we reduce the impact of prescribed burns?

Definitely. But more on that at the end of this latest series on the 4FRI environmental analysis.

Are controlled burns better?

What’s the evidence smoke from controlled burns will do less harm than wildfires?

For starters, the environmental analysis concluded wildfires will produce about 5,000 pounds of smoke per acre. A less intense controlled burn will produce about 3,500 pounds per acre. That’s just an average — but it means wildfires produce 43 percent more smoke per acre burned than managed fires.

Moreover, the Forest Service does controlled burns in the cool, damp spring and fall. The rules consider wind direction and air quality. So they don’t burn when the wind will blow smoke into the most populated areas — or when an inversion layer will trap smoke close to the ground.

Finally, crown fires are far more likely to spread into neighborhoods and consume homes. The plastics, metals and other substances in house fires have far more health effects than simple wood smoke, according to studies.

Granted, people living in forested communities like Payson, Pine, Snowflake and Show Low will still get a good dose of smoke from nearby controlled burns. But the bigger fires have a much larger health effect, because the smoke drifts into urban areas — with millions of people.

Lots of studies have documented the serious health risks from major fires. Far fewer studies have specifically compared uncontrolled wildfires to controlled burns.

One such study looked at the impact of smoke from different sources on kids 7-8 years old in California. The Stanford University study published in the Journal of Allergy and Clinical Immunology did tests on the immune systems and lung function of children exposed to smoke — including both big wildfires and controlled burns. The researchers compared those groups to children not exposed to smoke.

They found children exposed to wildfire smoke took in more pollutants, which had a bigger impact on their immune systems and allergy response. The children exposed to smoke from controlled burns faced a lower exposure and had less response, but still more than the kids who didn’t breathe in smoke at all. The wildfires produced the highest levels of nitrogen dioxide, polycyclic aromatic hydrocarbons, elemental carbon, carbon monoxide and particulate matter.

The current California wildfires show the potential human health disaster posed by not reducing wildfires. The Kincade and Getty fires remain uncontained, after consuming 80,000 acres, forcing 200,000 evacuations and threatening 90,000 structures. A study by Carnegie Mellon University concluded wildfire smoke has played a role in the reversal of air pollution gains between 2016 and 2018 — although the rollback of federal air pollution regulations also contributed. The levels of fine particulates has risen by 12 percent, which statistically could result in an additional 10,000 premature deaths — 40 percent of them in California, according to a report in High Country News.

A study by researchers from the University of California, Davis documented a big increase in emergency room and pharmacy visits during the 2018 wildfires in Northern California that displaced 300,000 people.

However, another study by Carnegie Mellon found little such impact from the 450,000-acre Mendocino Fire in 2018. That’s probably because the smoke didn’t drift into heavily populated areas or include chemicals from burning houses. That’s another argument suggesting controlled burns would have far less impact on human health than a rise in big wildfires.

But can we do something about the smoke from prescribed burns as well?

That brings us back to burning biomass.

About half the material produced by thinning projects consists of scraps, downed wood, duff and saplings — all with no value to loggers. So far, the only way to make use of that roughly 30 tons of material per acre lies in hauling it to a biomass burning plant and turning it into electricity.

But doesn’t that just put all that smoke into the air from the biomass plant?

Not necessarily. The single biomass plant in Arizona — run by Novo Power in Snowflake — strips out about 90 percent of the chemicals and particulates in the smoke, said Brad Worsley, president of Novo Power.

That means burning biomass in a power plant will remove tons of pollutants from the smoke of controlled burns after a thinning project.

And that could not only make the thinning projects economical, it could save lives.

Unfortunately, the Arizona Corporation Commission recently decided not to require power companies to buy enough biomass-generated energy to support about 50,000 acres of thinning projects annually.

The decision could cripple 4FRI. However, a narrow commission majority reasoned that electrical users in the Valley shouldn’t have to subsidize forest thinning efforts by paying a couple of dollars a month for electricity.

But hey — if the studies are right — this will give them a little extra money to cover the emergency room bill with the smoke of distant fires comes rolling into town.

Contact the writer at paleshire@payson.com

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