Forest treatments to reduce hazardous fuels made it easier to contain two wildfires in Arizona this year, according to Wally Covington, the director of the Ecological Restoration Institute, and a Regents’ professor of forest ecology at Northern Arizona University. In an op-ed at LiveScience, Mr. Covington said the fires had the conditions, and the chance, to burn hundreds of houses and destroy some of the state’s most coveted recreational tourist attractions, but they didn’t.
He is referring to the 21,000-acre Slide Fire and the 7,000-acre San Juan Fire which started in May and June, respectively. While they still grew into large fires, Mr. Covington said they could have become very damaging megafires, if not for the fuel treatments previously conducted on the Apache-Sitgreaves and Coconino National Forests.
Below is an excerpt from the article:
…The San Juan fire also provided lessons about how treated areas did what they were designed to do: slow a fire’s advance and restore a forest’s natural ability to self-regulate. How a wildfire behaves when it reaches a treatment area is a good test of how those treatments work. Fire crews and incident management teams reported that when the fire burned into areas that had been thinned, it burned with low severity and on the ground, not in treetops. The dry, frequent-fire forests of the West evolved with this type of fire, a slow-moving, low severity surface fire that would remove young trees and revitalize understory grasses and forbs. Anecdotal evidence from the San Juan Fire also suggests that the previously treated areas allowed fire crews to safely conduct burnout operations, thus enabling them to manage and control the fire.
Sometimes this works and sometimes it doesn’t. The 2011 Rockhouse Fire in Texas burned through recently thinned and rx fire-treated Ponderosa Pine stands in the Davis Mountains. In some areas, the crown fires were reduced to surface fires. In others, it didn’t matter, as the wind-driven (40-50mph on some days) fires crowned right through thin and burn. Even still, in some areas there was spotty crowning and spotty surface fire (great habitat mosaic).
Many stands, regardless of whether or not they had previous thin & burn, later died as a combination of fire and subsequent drought (no doubt exacerbated by fire) pressures, with little to no regen. The plus side of this is the increase in herbacous understory – lots of patchy, grassy green slopes all over the higher elevations of the mountains.
While it may have worked for Convington et al., thin and rx burn can’t be blanket applied to all southwestern pine forests, as has been done in the past. Some areas can be treated successfully, but some cannot because of past (and current) improper anthropogenic inputs into the system, along with a constantly changing climate.