Natural Selection
The October wildfires in San Diego brought national media attention to many of the issues that are front and center in wildland fire research. Given the complex nature of wildland fire, however, the reporting did not always get it completely right.
Nonetheless, media attention always brings the opportunity for highlighting wildland fire issues and improving public education. There are a number of interesting scientific debates related to fires in Southern California. First, the role of fire suppression in either constraining or increasing the frequency and size of the fires in Southern California has been hotly debated in scientific circles. In a related issue, researchers are looking at the impacts of fuel modification programs in promoting invasive weeds and grasses that ultimately shift landscapes toward more fire-prone systems.
And, given that these fires occurred in one of the most dense human populations in the country, there are a number of policy issues related to limiting growth and development and building homes designed for withstanding these fires that likely will receive increased attention.
For the few decades there has been an ongoing scientific debate as to whether the massive Southern California fires are natural and infrequent events in the chaparral ecosystem or are the result of a fire suppression policy that has allowed an unnatural accumulation of fuels. For decades, land-management policy in the region has been based on the idea that landscape-level fuel management can ultimately limit the size of these massive fires. A growing body of research has called that paradigm into question, and the results have big implications for land and fire management.
Back in 1983 Richard Minnich published a paper in Science arguing that the chapparral's natural fire regime was frequent, relatively small fires. The argument was based on analysis Minnich conducted using satellite imagery to compare fires that had occurred in chaparral systems between 1972 and 1980 on the Mexican and California side of the border. On the Mexican side where fire suppression was minimal, the pattern appeared to be lots of small fires. On the California side where fire suppression was supposedly high, far more acres had burned in seemingly large chunks. Minnich proposed the theory that frequent small fires on the Mexican side created a mosaic of different aged stands with a large proportion of younger, moister stands that kept fires small and less intense. So the argument went, if we would only allow more fires to burn, or use more prescribed fire to mimic that patterns found on the Mexican side, we could bring the large devastating fires under control.
The trouble was that Minnich had included two large fires in California from before 1972, and once these were removed the differences between the two areas is much less striking.
Since the early 1990s, a number of researchers including Jon Keeley, Max Moritz, Scott Mensing and C. J. Fotheringham have been publishing research that counters some of the basic propositions of the Baja fuel mosaic model. Keeley and his colleagues have shown that despite heroic efforts fire suppression has been far from successful in southern California since the late 1800s. The number of fires per decade has increased and there has been no significant decline in area burned. The researchers link the increasing number of fires and area burned to the expanding population density, not accumulating fuels.
In addition, one of the basic tenets of the Baja mosaic model is that smaller fire size becomes the norm in the absence of fire suppression, and that with suppression fire size increases. Keeley's research found just the opposite — that there has been no increase in the average size of wildfires. Indeed, said Keeley, the average wildfire size has significantly declined since record keeping began in the late 1800s.
The argument that younger fuels constrain the growth of large fires has also been questioned. Moritz has shown that fuel age doesn't affect the probability of burning — the large, wind-driven Santa Anna fire burn through young and old stands alike. In fact, much of the recent fire burned through stands that had burned in 2003.
Perhaps most importantly, research also is showing that prescribed burns and other fuel modification efforts may ultimately exacerbate the fire problem by introducing invasive plant species to the chaparral that can ultimately push out native species and increase the probability of burning. In fact, the increased frequency of burns is already converting large portions of the chaparral and creating a negative cycle of invasion by highly flammable exotic grasses.
Like most complex questions, solutions do not come easy, but most researchers agree that it starts with the built environment — focusing effort and resources on building future developments with fire risk firmly in mind, and developing strategies for protecting existing developments with a strategic fuel treatment programs aimed at creating defensible space around communities.
Has there been a shift in how the people view disaster risk and their collective and individual responsibility to prevent it. The 2003 fires actually destroyed more homes and killed more people than 2007 fires but probably received 10% of the media coverage. What caused the increased interest?
During the San Diego fires, TV viewers saw aerial views of flames coming out of the canyons and battering against tightly packed hilltop subdivisions. Even reporters and viewers who had never heard of the term wildland-urban interface started asking the fundamental question — why are people still building homes in these areas?
The answer is easy — California is gaining population at the rate of about 600,000 people per year. That is the equivalent of adding a Sacramento to the state every year. With a constant demand for new housing, developers keep pushing into these fire traps, building homes around places with names like Chimney Canyon and Hell Hole Canyon.
Without serious land-use planning, growth restrictions and building codes, the problem will continue to grow.
California actually has been a leader in addressing fire risk through local and state programs requiring defensible space and fire-resistant construction. The state's defensible-space program requires homeowners in high fire areas to maintain 100 feet of cleared vegetation away from the home. Local fire departments conduct inspections and if a homeowner is not in compliance the work may be done for them with the bill added as a lien on their property. While this program has been effective, enforcement is still difficult. Officials across the state inspected nearly 117,000 properties in 2005 and 2006 but issued only 160 defensible-space citations. Officials say that the program only passed in 2003, and that they are giving homeowners opportunity and time to comply voluntarily before they get much stricter.
Building codes also are much stricter in California than they are in most other parts of the West. Most counties require fire-resistant roofing and siding materials and in some cases double-paned windows for new developments. However, very few areas have gone so far as to require retrofitting of existing homes. And, more importantly, as Richard Halsey of the California Chaparral Institute points out in a recent editorial in the San Diego Union-Tribune, defensible space and stucco siding is not going to save a home against 100-foot flames and 80-mph winds if it is located in the wrong place. “When you put a flammable structure in a flammable corridor it's like putting a bowling pin in a bowling alley — ultimately it is going to be taken out,” writes Halsey.
Even scientists who have feuded for years about the causes of the Southern California fires agree that the solutions are only going to come with serious land-use planning that addresses fire risk.
Stevenson Ranch near Santa Clarita is the model of the master-planned fire-resistant community. All of the homes are constructed to withstand radiant heat and flying embers using concrete tile roofs, double-paned heat-resistant windows and enclosed eaves. Stone and concrete culverts protect homes adjacent to canyons and other open space, and many of the swimming pools are equipped with valves to allow firefighters to draw water. A 200-foot greenbelt with fire-resistant landscaping rings the properties, and the development has been laid out with firefighter access and evacuation in mind.
Fire officials were so confident that the community would survive the recent fires that they allowed residents to shelter in place as the fires approached. Most watched the fires from their lawns, hoses at the ready to extinguish any embers that managed to ignite anything on their property. Not a single home was destroyed in Stevenson Ranch during the latest round of fires.
Obviously, not everyone can afford to live in places like Stevenson Ranch. According to the California Department of Forestry and Fire Protection, over five million homes in the state are at high to very high risk in wildfires, and 84% of those are in areas that could be designated wildland-urban interface. It is likely that many new developments will be built according to at least some of the ideas that guided construction of Stevenson Ranch and other communities like it, but there are still a whole lot of existing homes and developments that will remain vulnerable.
The argument of responsibility over western wildfires has long simmered over the question of forest management versus land-use planning. Non-federal entities consistently point to mismanaged forests and fire suppression history as the culprits when fires run wild. On the other side, federal land-management agencies always drag out statistics on the growth of the wildland-urban interface and the percentage of their efforts and budget that goes to fighting interface fires.
Both sides are correct. Forests have been mismanaged, too many fires have been suppressed and development has been allowed to expand dramatically without any thought to risk or planning.
Roger Kennedy, the former director of the National Park Service has argued that federal policies have led to the expansion of the wildland-urban interface. “Taxpayers build roads and power lines into the firetraps and insure the mortgages of those who live there. When the fire closes in, we pay to rescue the victims. Thus we encourage construction while risking the lives of both homeowners and those who rescue them,” he argued in a recent New York Times editorial.
Kennedy proposes immediate actions to remedy the problem through the creation of a National Flame Zone Atlas along the lines of the national floodplain maps. The atlas would be used to decide whether subsidies for infrastructure development and mortgage insurance would be granted or withheld.
We already have a good idea of the existing and potential overlap of high risk fire areas and housing. Technology is making it more and more feasible to create detailed maps that could guide fuel treatment efforts on a landscape scale to protect communities and restore forest health, while providing guidance for land use planning. What is lacking is the political will to make the tough policy decisions that will represent dramatic course changes in terms of land management and land use planning — budget allocations, zoning, expansion of wildland fire use — the types of actions that could make a real difference.
Misconceptions persist, but society is becoming much more aware of the human and economic consequences of placing homes and people in the path of hurricanes, floods and fire, and with awareness comes questions. Members of the firefighting, land-management, and scientific communities better be ready to answer them.
Josh McDaniel is the editor of the Advances in Fire Practice, a subsite of the Wildland Fire Lessons Learned Center Web site focused on bringing efforts and ideas to the forefront that leaders in the fire management, practice and research communities have identified as innovative and widely applicable. It provides access to critical and proven fire information and resources. The new Advances in Fire Practice section can be reached directly by going to www.wildfirelessons.net/AFP.net.
