Thousands of acres in the Tonto National Forest continued to burn over the weekend.
Ironically enough, Forest Service rangers couldn’t be happier.
Instead of rushing to douse the flames, forest managers are mostly taking advantage of the cool conditions to let the fires burn — mindful of the growing body of research demonstrating the value of low-intensity fires at the right time of the year.
Recent studies have demonstrated that such low-intensity, controlled burns actually increase the diversity of plants and wildlife in the forest. Another recent study of tree-ring data going back hundreds of years has underscored that Southwestern forests have adapted to fire frequencies as often as once every two years.
So the early fall flush of fires burning now may do far more good than harm, say forest managers.
Over near Young, the Tanner Fire continues to burn nearly a month after a bolt of lightning started the blaze at the peak of Armer Mountain in the Sierra Anchas.
Crews this week will close Highway 288 in places to build a fire line around the blaze, according to John Thornburg, fire management officer.
“The fire remains within our management area and continues to burn heavy pockets of fuel which prevents catastrophic wildfires in the future.”
The fire put up a plume of smoke from the Tonto Basin, Globe and Young. Downdraft winds from a thunderstorm off Armer Mountain pushed the fire across Highway 288 Saturday evening around 7 p.m. and the fire burned through a dispersed camping area. No campers were present and no structures were lost.
On Monday, crews closed Highway 288 from Reynolds Creek south to the A-Cross Road.
Meanwhile, the lightning-caused Frio Fire continued to burn in the Pinal Mountain range. The fire has burned 3,600 acres since Aug. 17 and is 90 percent contained. Crews will be setting backfires this week to control the spread of the fire, especially on its eastern flank.
“Resources are assigned again today to ensure that we keep the fire where we want it to be, doing what we want it to do,” said Brad Johnson, Globe Ranger District spokesperson.
“We predict that smoke will continue to be visible for the next several days. As fire activity and spread are reduced, smoke impacts will be lessened considerably. We thank the public for their patience and support as we finish this project which will considerably lessen the danger of catastrophic wildfire in the future.”
Low intensity fires after the monsoon season actually benefit Southwestern forests, removing tree thickets, returning nutrients and preventing destructive crown fires — mostly during May and June. Such high intensity fires leaping from treetop to treetop sterilize the soil, creating a water-resistant crust and consume every tree and shrub over large areas.
Although low-intensity controlled burns reduce the chance of such catastrophic fires, many residents still suffer health problems from the smoke. For health information concerning smoke effects, please contact the Gila County Division of Health and Emergency Services, 5515 South Apache Ave., Suite 100, Globe, AZ 85501, (928) 425-3231 ext. 8888.
Residents can also stay updated on fires at www.fs.usda.gov/Tonto. To report a wildland fire, the fire emergency number is 866-746-6516, or dial 9-1-1.
A recent tree-ring study demonstrated how adapted most forested systems have become to regular, low-intensity fires, according to findings published in Applied Vegetation Science and Physical Geography.
Mature pines more than 500 years old often show 14 or more fire scars dating back to the mid 1600s, which means they generally survived a fire every 2-10 years, according to the researchers from Texas A & M University.
The researchers noted that for centuries Native Americans regularly set grassfires, knowing such frequent fires actually helped the forest.
However, fire frequency began to drop dramatically after the 1930s, when the U.S. Forest Service introduced its “Smokey Bear” campaign to prevent forest fires.