Southwest blazes this year less severe than initially thought — study

Photo from USGS

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.

Wallow fire map

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.”
Inconclusive results?

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.

6 thoughts on “Southwest blazes this year less severe than initially thought — study”

  1. It is QUITE early to be totaling wildfire damages. Come back in 10 years and we’ll see significant additional damage, including flood erosion, accelerated bark beetle activity and the loss of ponderosa pine seed sources. There will also be unsalvaged parts of the fire that will re-burn in the next 20 years. I’d bet if you overlay the protected wildlife zones on top of the burn severity maps, you’ll get an “interesting” match. If the fire folks can have “Appropriate Management Response”, why can’t foresters have the same leeway to respond to dangerous fuels buildups?!?

  2. Sharon, check out the link to this website. It tells a different story.

    It’s the USFS Wallow Fire 2011, Large scale event recovery- rapid assessment team- “Forest vegetation salvage report”-Sept. 2, 2011

    On page 2 is the “overstory mortality estimates”.
    It shows 38% suffered 75-100% mortality. The last I looked that was considered “severe”. (vs. the 17% on the WEG study)
    20% is 50-75%-the last I looked that was around “moderate severity”. (vs. 14% on the WEG thing)
    23% is 25-50% mortality-which is around “low”
    and 15% is 0-25%

    Yes, I have to agree with the USFS gal quoted above. It would seem there is quite a difference between “soil burn severity” and “overstory burn mortality”.

  3. Most of the fuel reduction projects I see cause >50% mortality but leave very few snags behind. Woodpeckers, marten, goshawk, and salmonids would call that a tragedy.

    • If you haven’t noticed, Doug, we now have at least 25 million acres of dead and dying forests. With lodgepole densities being very high, and most of those 25 million acres containing lodgepoles, let’s assign a conservative number of trees per acres at 50. So, that means we have at least 1.2 BILLION snags for wildlife, well beyond any past amounts in the last several thousand years. So, now that we have all those dead trees, what do we do with the emissions of all those trees rotting and burning, all at once? Do we continue to radically-expand the encroachment areas of lodgepole pines, at the expense of fire-adapted ponderosa pines forests and endangered species habitats? Do we continue our bias against the ponderosas, in favor of the invasive lodgepoles?

      Also, goshawks and pine martens don’t prefer “snaglands”. Many species are listed solely because of critical habitat loss. So, why are we continuing to allow those habitats to burn, maybe never to return? Should we continue to look the other way when at-risk habitat is “preserved” in all its flammable glory, locking in future catastrophic firestorms?

  4. I’d like to pick at this “study” a bit more. I’d like to ask the authors two things, which I know I will not get the answers to.

    #1- While you admit in your study that a major source of your info is the “Burned Area Reflectance Classifications (BARC)”, which you got from the USFS, nowhere do you tell the reader that BARC is a measurement of “soil burn severity”. In every instance when the USFS refers to BARC it is accompanied by a reference to a measurement of “soil burn severity”. In no instance do you tell the reader it is a measurement of “soil burn severity”. Why is that? Your “burn severity” map is identical to one the USFS has but theirs is labeled “soil burn severity”. One may get the impression that your “burn severity” refers to “forest burn severity” instead of the much more obscure “soil burn severity”. I’m sure you would like to clear that up with the readers.

    #2- Why did you not address “overstory canopy mortality” in your “study”. You know,like in how many trees were burned. How do you reconcile the USFS data that shows 38% of the “forest vegetation” suffered high burn severity with your claim that only “16% burned at high severity”. It’s rather a glaring ommision. Perhaps that dataset wasn’t available from the USFS. Perhaps in your “amended” study you could address that figure.

    The truth is that over half the forest is “black”, and only 15% of the “forest vegetation” could be considered burned at a low severity. This fire has condemned the “locals” to a forest they won’t want to go into for generations. No more cool Sunday drives in the shady forest on a hot August day. No one wants to pitch their tent at “Camp Chernobyl”. I have a feeling that serious researchers will be flocking to the Wallow to study the effecacy of thinning treatments and the catastrophic effects that wildfire has on endangered species. I hope they have a good press agent.


Leave a Comment

Discover more from The Smokey Wire : National Forest News and Views

Subscribe now to keep reading and get access to the full archive.

Continue reading