The Wallow Fire is now the largest in recent Arizona history, encompassing more than 500,000 acres. The media discussion of the fire often leads to misinformation and misunderstanding of wildfires, and feeds the political agenda of politicians, and industries from developers to the timber industry.
One of the problems of media coverage is that most reporters have little or no training in ecology, much less in-depth understanding of wildfire ecology. Context for large blazes like the Wallow Fire are often missing from reportage. The emphasis on fuels makes for easy reportage, but misses some important nuances that lead to simplistic solutions—the common refrain that if we only logged more of the forest such fires would be prevented.
It also tends to reinforce the idea that thinning is needed in all forest ecosystems, when in fact, many fire regimes in higher elevations and more northern locations are more or less still within historic norms.
Furthermore, there is a tendency to focus on the most unfortunate losses which can exaggerate the perception that such fires have done a lot of “damage” to people, seldom holding people accountable for their own losses because they have chosen to build in a fire-prone landscape.
First, large wildfires do not just happen. Media attention on fuels as the driving force in large blazes like the Wallow Fire misses an important and critical factor—fire climate/weather conditions. You can have all the fuels in the world, but if the conditions are not right for fire spread, you won’t get a large blaze.
Climatic/weather conditions are driving the Wallow Fire. The Southwest is experiencing what is described as a 500 year drought. We have not seen such dry conditions in centuries. Is it not surprising that wildfires are larger than in the recent past—when the climatic conditions have no analogy in the recent past?
Contributing to the large blazes are extreme fire weather conditions. Humidity is often 10% or less. Even green trees in the region are drier than kiln-dried lumber. Such green trees still laden with flammable resins and fine fuels in the form of needles and small branches are actually more flammable than dead trees.
The other major ingredient in the Wallow Fire and all large blazes is wind. Every increase in wind is not linear but exponential. A 20 mph wind doesn’t just double fire spread over a 10 mph but it can quadruple spread or more by throwing fire brands and sparks far beyond the fire perimeter. Winds in the Wallow Fire area have gusted to 40-50 mph, fanning rapid fire spread.
Another common reporting problem is the focus on the outer perimeter of the fire. The Wallow Fire has burned an outer perimeter of more than 500,000 acres; however, a significant amount of the land has not burned at all. There are many areas with a nice mosaic of burned and unburned forests.
And fire-fighting efforts themselves also contribute to the large acreage of the fires. Fire fighters, especially under dangerous and severe fire weather, do not attack wildfires head-on. Rather they use fire to fight fire, purposely setting blazes far from the fire front to burn out the fuels, and thus slow fire spread or to keep fires from burning homes and towns.
I do not know how many acres of back fires were set in the Wallow Fire, but in other large blazes across the West, as much as one third of the forest area burned is a direct consequence of fire fighting efforts, thus adding to the large acreage reported. Without acknowledging the contribution of fire fighting to total acres, the public gets an exaggerated view of the fire’s severity.
Another factor contributing to the fire’s large size and cost is the presence of homes in the Wildlands Interface. Across the West, perhaps the biggest factor contributing to increasing fire-fighting costs and also risk to fire fighters is the irresponsible actions of county commissioners and others who regularly approve home construction in the “fire plain”. In far too many instances, rural county commissioners promote home construction in fire-prone landscapes.
The fire plain is like the flood plain of a river. Sooner or later there will be fire in such areas—permitting home construction in such fire-prone landscapes costs all taxpayers who shoulder the costs of fire protection. This is a huge subsidy to these home owners. Ironically, in many cases, those who are demanding that the public pay for fire protection and/or forest thinning projects are the same ones who oppose any reasonable limitations on home construction in fire prone landscapes and frequently complain about excess taxes and government regulation. But they are the first with their hands out when they demand compensation if their homes are burned and are most vocal in their criticism of fire fighters for not protecting their property.
Finally there is the fuel issue. Historically, frequent low intensity fires burned through grassy understory of ponderosa pine forests killing tree seedlings and created open, park-like stands in some areas. It’s important to note that even in the past, not all ponderosa pine stands were “park-like”, nor were all blazes necessarily low intensity. Under extreme climatic conditions, large blazes did occur. So whether a fire like the Wallow Fire is really out of the historic norm depends on the spatial and temporal scale one is considering. A 500 year drought is not the recent historic condition. Nevertheless, there are reasons to believe that human activities have exacerbated the present conditions that have led to a greater abundance of dense forest stands.
There is general agreement that many ponderosa pine forests in the Southwest exceed historic tree densities. However, the ponderosa pine forests burned by the Wallow Fire are not hugely out of historic range of viability compared to other parts of Arizona. Eastern Arizona contains the largest percentages of mature/old growth ponderosa pine.
Furthermore, some of the higher elevation areas are cloaked in spruce and fir forests which tend to burn in stand replacement blazes and are well within historic conditions.
Thinning forests to reduce forest density can sometimes work to reduce the intensity of blazes and slow the spread of fires. However, we should recognize that we are treating the symptoms, instead of the ultimate cause of changes in forest density and composition.
One of the most important factors has been livestock grazing. Grazing has eliminated the fine fuels or grass cover that once dominated the forest floor in many low elevation forest types across the Southwest. These grasses regularly burned killing tree seedlings.
Trampling by hooves has disrupted soil crusts which in the past helped to reduce soil erosion, the loss of moisture, added nutrients to the soils, and prevented germination of annual species like cheatgrass.
The loss of grass cover and soil crusts by livestock grazing has also reduced the competition for water by tree seedlings, creating more favorable germination and growth condition for trees.
Despite the well known effects of grazing on fire regimes in this landscape, federal and state agencies allow livestock grazing to continue, contributing to the exact same conditions that have led to the dense tree stands.
Adding to the problem has been past logging of old growth pine. Large pines with their thick bark and self pruning loss of lower branches were more resistant to fires and less likely to “crown” out as blazes running through the tree tops. Loss of the larger pines has permitted many smaller trees to survive on the sites, leading to denser forest stands. However, the forest area burned by the Wallow Fire is probably closer to historic conditions than areas nearer Flagstaff where large mills eliminated nearly all the old growth forests.
Compounding the effects that grazing and logging has had on forests, is the on-going policy of fire exclusion. Despite the well known influence of wildfire on thinning ponderosa pine forests, public agencies seldom permit wildfires to burn unimpeded. The good thing about the Wallow and other large blazes is that it is resetting the forest landscape, removing dense tree stands. However, if agencies like the Forest Service continue to suppress fires, and allow livestock grazing, it will ultimately lead to the same dense tree conditions again.
Livestock grazing along with logging and road building has allow exotic weeds to spread throughout these forests. Many of these exotic species are more flammable than the native species they have replaced.
Thinning forests as proposed as a “cure” to the present forest situation may contribute more flammable forests in the future, especially if the on-going activities including livestock grazing, fire suppression, ORV use, and logging continue.
Those who are looking for simplistic answers often support thinning of these forests as a panacea for large blazes. Thinning near towns can contribute to more effective protection of communities. By reducing fuels near towns, one can deflect, slow, and sometimes even stop blazes. But that assumes that you can focus a lot of fire fighting man-power on the fire lines near communities.
However, widespread thinning, especially if it involves removal of larger trees, is not benign and the consequences of logging may be worse for forest ecosystems than anything that results from a large blaze. For instance, if logging requires new roads, it greatly increases the negative effects. Roads create access for people for hunting, trapping, and reduce the security cover for wildlife. Logging roads are also a major source of sedimentation in streams. There is sedimentation after a fire as well, but in most areas, sedimentation levels return to pre-fire levels within a few years, while roads “leak” sediments for decades. Logging can remove biomass from the forest, reducing the future occurrence of rotten logs and snags that are important to many wildlife species. As previously mentioned, disturbance of soils by logging equipment and road building can spread exotic weeds. Unless all these negative impacts are considered in thinning plans, one can’t determine whether logging will have a positive overall influence upon forest ecosystems or perhaps negative.
George Wuerthner’s New West blog is “On the Range.”