When officials decided not to stop the Tehipite fire east of Fresno, they got three big payoffs -- a cheaper fire to manage, reduced risk for firefighters and cleanup of dangerously overgrown forest.
But this fire -- which has burned 11,000 acres since mid-July -- worries the San Joaquin Valley Air Pollution Control District.
Officials fear that smoke and ozone-making gases might harm air quality.
The district needs further analysis to determine if the Tehipite and another blaze, called the Hidden fire, caused bad-air days in the valley. State records show that this region had its highest September total of ozone violations in five years.
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Then a familiar debate begins, pitting beneficial forest fires against unwanted smoke. The valley's air quality is among the worst in the country, but Sierra Nevada fires are natural and necessary to eliminate excess growth that fuels catastrophic fires.
No control over natural burns
Air violations in the valley won't count against the district later if fires caused them. But while the district becomes involved in controlling smoke from any human-made fire, it has no authority over natural lightning-caused blazes, such as the Tehipite fire.
"I can't order them to put it out," said district executive director Seyed Sadredin.
In June, the state got a taste of poor air quality from fires burning overgrown forests. Hundreds of lightning-caused fires in Northern California sent tons of ozone-forming gases and soot into the air, causing violations throughout the state.
The valley had violations for soot and ozone in June. The soot violations occurred from Stockton to Bakersfield for four consecutive days, which is considered unusual.
But there were no soot violations in September, according to state records. The Tehipite and Hidden fires have not been as big a problem for the valley, according to federal officials.
Parks officials added that air quality is not the only factor when evaluating whether to stop a fire or let it burn. The bigger concerns are protecting the public and keeping firefighters safe.
But if needed, the National Park Service and other federal agencies could douse parts of the Tehipite fire to eliminate excessive smoke.
Smoke is one of the main reasons park officials moved quickly to extinguish the Hidden fire in Sequoia. It was contained in late September at about 3,700 acres.
The fire was near the Generals Highway. There also were nearby tourist attractions, such as Crystal Cave and the trail to the Muir Grove of giant sequoias, and officials worried about how smoke would affect visitors.
"We have a lot to lose if there's a problem with air quality," said Deb Schweizer, fire information specialist with Sequoia and Kings Canyon. "We want to protect the public and the forest from poor air quality."
When the Tehipite fire started in Kings Canyon National Park, park officials tried to stop it, hoping to avoid smoke problems. But seven firefighters were injured in steep and dangerous terrain, Schweizer said.
Officials re-evaluated and decided to let it burn rather than risk more injuries in one of the most remote places in the park. It has since burned into the Sierra National Forest.
A good cleanout needed
U.S. Forest Service officials are helping by watching air quality carefully in the foothills. They have placed portable air monitoring devices at Hume Lake, North Fork, Prather, Trimmer and Oak- hurst, said Trent Procter, the service's regional air quality program manager.
But even as they worry about the smoke, park officials acknowledge they want natural fires that will help the forest ecosystem. The Tehipite fire offers an ideal opportunity.
"I'm guessing that the Tehipite fire is burning in a place that hasn't had a fire in 100 years," said fire ecologist Anthony Caprio of Sequoia and Kings Canyon parks. "The forest needs more frequent fire."
Allen Clyde, owner of Clyde Pack Outfitters at Dinkey Creek and Wishon Reservoir, said he often passes through the overgrown area and considers fire risk to be extreme. He cautioned visitors to avoid even lighting a cigarette.
"If ever there was a place that needed to be cleaned out with a fire, this was it," he said. "You'll see how much good it will do next spring."
If all goes well, the fire will slowly wipe out low-growing shrubs, snags and forest debris until the snow flies -- just as such small fires have done for thousands of years.
Small, natural fires open up the forest for a variety of sun-loving plants and trees, such as the sugar pine. Large, old trees in the Sierra generally are fire resistant, as long as the fires don't feed on thick underbrush and build up into the crowns of the trees.
But decades ago, government policies called for snuffing out all fires. Years later, officials realized that the forests had become dangerously overgrown.
Now, millions of acres in the Sierra and the West are filled with dense forests. They are primed for wildfires that could cost lives in mountain communities, destroy centuries-old trees and leave a pall of smoke for weeks.
It also is a lot cheaper to let a fire burn. The price tag on the Tehipite fire is about $700,000 officials said.
The cost of the Hidden fire was 10 times higher -- more than $7 million.
The Hidden fire may have been managed differently if it had entered a grove of giant sequoias, Schweizer said. It was near the Suwanee, Muir and Skagway groves of giants.
"Giant sequoias benefit from fire," she said. "But there was just too much potential for problems with the Hidden fire, so it was suppressed."