Sawtooth fire as it moves through the desert landscape. Photo taken near Mocking Bird Ln, Morongo Valley by Taya Lynn Gray of the Desert Sun newspaper.
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There's nothing like a false statement about a place you love to inspire a vigorous defense.
If one were to identify the primary objective of the California Chaparral Field Institute it would include setting the record straight about the impact of wildfires on California native plant communities. Unfortunately, there remain a significant number of misconceptions out there. Our response to a quote in the July 13, 2006 issue of the Desert Sun newspaper about the Sawtooth fire, a desert blaze that ultimately burned 61,700 acres near Yucca Valley, California, is a good example of what we do.
The paper reported that a local geographer said native wildflowers were responsible for carrying the blaze and that there wouldn't be another fire like it for "another century or so, depending on heavy rainfall." Not only were both contentions false, but they contributed and reinforced the numerous misunderstandings the public has about native ecosystems and the role of invasive, alien weeds in changing natural fire regimes, especially in desert ecosystems.
Although there may have been some areas where dried, native wildflowers contributed to the total fuel load, the contention that they were the major contributors in allowing the flames to carry is incorrect and is based on observations that do not apply to the Sawtooth fire’s area of spread. In addition, the suggestion that the area would likely not burn for another century fails to consider the flammable mix of alien, invasive species such as cheatgrass, red brome, and mustards that will likely spread further into the fire scar, especially after a good rainy season. These plants make a significant contribution to high levels of fine fuels that will continue to threaten the area with increased fire frequencies. There are no historical records of large fires like the Sawtooth occuring before the invasion of alien grasses. Now such fires are becoming increasingly frequent, endangering the continued existence of native desert ecosystems.
Below is a portion of an article from the August, 2006 issue of The Chaparralian that explains this situation in more depth. If you would like a copy of the entire issue, please see our Membership page.
A blanket of cheatgrass and red brome covers the ground of a desert hillside along Highway 62, south of Yucca Valley, California. Dense fuel beds composed of alien grasses and weeds such as this are the primary carrier of wildfires throughout the Mojave and Sonoran Deserts.
The Denialists: Desert flames and Wildflowers
(why alien grasses make the difference)
By Richard W. Halsey
I was asked a surprising question while at the 16,800 acre Horse fire in eastern San Diego County (July 2006). In a conversation with several people about how another fire near the desert town of Yucca Valley had been fueled primarily by alien grasses, I expressed concern over the transformation of many native landscapes to non-native grasslands, a process also known as type-conversion. Afterwards I was asked, “Has type-conversion of chaparral really been proven to occur?”
I pointed up to a nearby hillside covered with weeds. “It’s happening up there,” I said. “Areas that have been repeatedly burned lose nearly all their native species and end up a monoculture of alien, weedy annuals; lots of fine fuels ready to carry a fire nearly every year. It becomes a self-perpetuating process.”
Although I knew the question was a sincere one, it was also very troubling. How could such a significant threat to native landscapes not be as well known and understood as other environmental problems?
Poor attention by the press and lack of awareness of the issue by traditional conservation organizations provides part of the answer. But I fear another reason why the threat of type-conversion is grossly underestimated is due to a select group of individuals who have chosen to dismiss the problem in favor of promoting favored theories and specialized agendas. A helpful way to think of these individuals is as “denialists.” It is important to note, however, that denialists are not the same as skeptics. Skepticism is a crucial and healthy part of analyzing theories and ideas. Denialists, on the other hand, confuse the process by either consciously or unconsciously denying verifiable scientific truth because it does not fit into their personal view of the world.
The problem with denialists is that regardless of the quality of their data, they are frequently viewed as equals to others who actually know what they are talking about. Denialists use this to their advantage whenever their favored theory is challenged. The resulting “debate” is seen by the public as simply one of expert vs. expert without any objective analysis of what is being said. The media fosters this approach because it provides personal drama to what the public might otherwise view as boring science.
Classic forums for denialists are government hearings held by federal or state legislative committees. One would think a balanced group of individuals would be called to testify in order to inform those listening. However, the participants of these hearings are often selected by the majority party in order to slant the discussion in one direction or the other.
Why would anyone want to ignore or minimize the threat of type-conversion in native ecosystems due to increased fire frequency? Wildfire and how to deal with it is fraught with politics, economics, and strong opinions. Any issue complicating land management decisions under such conditions is hotly debated and prone to denialist rhetoric. The “wildflower/grass controversy” revolving around the Sawtooth Complex fire near Yucca Valley may provide one such example.
It was reported in the July 13, 2006 Desert Sun newspaper that a geographer from the University of California said native wildflowers carried the fire’s sweep across the desert. In addition, he predicted the area would not burn again for “another century or so, depending on heavy rainfall.”
These statements led to a whirlwind of emails and conversations over the following week because those familiar with the area knew that alien weeds, mainly cheatgrass and red brome, had created a dangerous fuel bed throughout the desert. Attributing the fire to native wildflowers was not only contrary to what was known, but it fostered two unfortunate misconceptions; the fire was an unusual event caused by record rainfall and that native plants were once again the responsible agents of a destructive inferno. The geographer’s statements were so unbelievable to some that they questioned the accuracy of the quotes. However, both the accuracy and emphasis of the quotes were later confirmed by the reporter and the geographer himself.
After assembling information from multiple on-site visits, interviewing or hearing from numerous individuals who were either on the fire or have an intimate knowledge of the area (including local ecologists, land managers, and firefighters), and studying official post-fire reports from the US Forest Service and the California Department of Forestry, there is no question that the geographer’s perceptions and predictions were wrong.
Post-fire inspections of unburned islands within the fire perimeter (caused by fire suppression activity or topological features) revealed the remains of very few native wildflowers. In fact, it was difficult to find any at all in most locations. Instead, the overwhelming fine fuel component was cheatgrass and red brome. Fuel conditions within the burned area prior to the fire were similar based on interviews with local residents and scientists. Native wildflowers were not responsible for carrying the flames.
The only way the desert portion of the Sawtooth Complex fire could have carried the way it did was because alien grasses created a continuous fine fuel bed in many areas, with especially dense concentrations under trees and shrubs. Coupled with high winds and record temperatures, this unnatural fuel bed facilitated the rapid movement of embers and heat, quickly igniting one shrub after another. Although it is extremely difficult to know exactly what the historical fire regime was in such desert regions, the scientific consensus is that desert fires in the past were limited in size because there was not a continuous fuel bed to carry the flames.
The suggestion that the fire was only made possible by heavy rains stimulating abundant native wildflower growth fails to consider the flammable mix of invasive species and how they have altered both fire behavior and frequency (one wonders how the alien grasses responded to all the extra rain!). Desert fires are becoming more common and are increasing in size not because of increased rainfall, but because of increased volumes of weedy annuals.
Why would anyone ignore the impact of alien weeds on fire frequency and focus instead on native wildflowers?...
See the full article by requesting a copy of The Chaparralian. Details on our Membership page.
Additional information on Sahara mustard, an alien weed having serious impacts in the Sonoran Desert, can be found at the .
Some excellent references:
1. [Proceedings]
2. [Journal Article]
3. [Technical Report]
4. USGS Fact Sheet.
5. [Proceedings]
Pipes Canyon after the Sawtooth fire. Some of the pinyon-pines here were over 1,200 years old. Nearly all were killed. The Joshua trees were hundreds of years old. They can resprout from the base, but it will take many generations for them to return to their former beauty. This system does not handle fire well.
