Thanks to Matthew Koehler for suggesting this for the blog.
WILDFIRE: Southwest blazes this year less severe than initially thought — study
April Reese, E&E reporter/Published: Thursday, September 29, 2011
While much of the public saw the record-setting wildfires that burned through Arizona and New Mexico last summer as disastrous, the fires were actually less severe than many thought and are likely to bring significant ecological benefits over the long term, according to a new study from an environmental group.
But Forest Service officials say it is too early to draw broad conclusions about how the fires affected tens of thousands of acres scorched by the Wallow, Horseshoe II, Las Conchas and Pacheco conflagrations.
A new study issued by WildEarth Guardians asserts that fire damage caused four major blazes across the Southwest last summer, including the Wallow Fire (mapped above), was not as extensive as initially thought. Map courtesy of WildEarth Guardians.
Bryan Bird, public lands program director for WildEarth Guardians, who co-authored the report with Kurt Menke of Bird’s Eye View GIS LLC, an Albuquerque-based company specializing in geographic information systems, said his group felt there was a need to educate people about the true impacts of the blazes.
“There was just such a wide perception out there that these fires were just completely destructive, we wanted to make clear that these fires were in some areas beneficial,” Bird said.
By examining satellite data measuring vegetation characteristics before and after the fires, Bird and Menke concluded that lands within the four fire zones burned in a mosaic pattern, with fire severity ranging from high to low.
For example, within the perimeter of the Wallow fire, which burned 538,000 acres on the Arizona-New Mexico border, more than 64 percent of the lands burned at low intensity or not at all, while 16 percent burned at high severity and 20 percent burned at moderate severity.
For the Las Conchas fire, which scorched 156,600 acres in northern New Mexico, including parts of Bandelier National Monument and the Valles Caldera National Preserve, about 20 percent of the area was severely burned, while most of the lands burned either at low severity (39 percent) or moderate severity (about 29 percent).
How the fire behaved in a given area depended on a range of factors, including forest type, dryness and whether fuel treatments had been done in the area.
“These four fires exhibited very different characteristics and consequences because of the wide variety of ecosystems in which they burned as well as the variable conditions,” according to the report, which notes that the findings need to be verified with field surveys. “Not all of the acreage within the fire perimeters burned severely, and in fact much was unburned or burned only at low and moderate severity.”
But Penny Luehring, leader of the Forest Service’s national Burned Area Emergency Response program, which is based in the Southwest regional office in Albuquerque, N.M., said Bird and Menke based their assessment on soil burn severity data, not vegetation burn severity data, and therefore it cannot be considered conclusive.
“The information that they have in their report aligns quite well with what the Forest Service has collected in terms of soil burn severity, but it’s a measurement of the severity on the soil itself, not a measurement of the effect on vegetation,” she said. “You could you have a lot of burned trees, for example, and you wouldn’t notice them on a soil burn severity map.”
Luehring said the Forest Service plans to conduct field assessments of the effects of the fires on trees and other vegetation over the next several months.
While the report’s conclusions may well turn out to be true, Luehring suggested the data are not yet there to support them.
But Bird said he stands by the report, explaining that the datasets he and Menke used, which were from the Forest Service’s “Burned Area Reflectance Classifications,” did include information on vegetation changes as well as effects on bare soil.
Melissa Savage, an adjunct professor at the University of New Mexico and director of the Four Corners Institute, a Santa Fe-based organization that provides scientific expertise to communities undertaking ecological restoration projects, said she believes the report’s conclusions are likely to be borne out with field studies.
“It will probably be largely verified when we get on the ground,” Savage said.
The report makes several recommendations, including using prescribed burns or naturally ignited fires every five to 20 years to maintain the fuel-clearing benefits of fire and keeping development out of forested areas.
New Mexico still has about 600 square miles of undeveloped private lands adjacent to fire-prone public lands, and Arizona has 400 square miles of such lands, the report notes.
Click here to read the study.
Reese writes from Santa Fe, N.M.