In September, as the fire season slows and the smoke clears, it s obvious that 2012 was another big, bad year for wildfires. With a heat wave, a drought, and fires taking out thousands of homes in Colorado Springs and elsewhere, it seemed like everyone was talking about the weird weather this summer. Finally, after years of warnings from climate scientists, the mass media is including coverage of the role that climate change is playing, driving more extreme and unpredictable weather.
To me, this is the most striking statistic: this year, the number of individual fires was low, only 76 percent of the ten-year average. However, the acreage burned by wildfires was unusually high, about 133 percent of the ten-year average. (Data) We had more damage from few fires, a simple statistic that shows that, overall, fires are becoming more intense, more damaging to the ecosystem, and more dangerous for firefighters.
This new, increasingly intense fire regime requires a new way of thinking about fire science, particularly in post-fire restoration. Historically, in forests adapted to wildfires, burns periodically cleared out brush and dead trees, while most of the established, healthy trees survived. Today, after decades of fire suppression policies, forests are stockpiled with these accumulating fuels, what scientists refer to as a fire debt. Fuel-laden forests, combined with climate changing risk factors like mild winters, early snowmelt, and summer drought have created a perfect storm of conditions for mega fires.
This is the catch-22 of forest management. The forests need small fires to stay healthy but intense fires like those we ve seen in recent summers can cause such significant damage that the forests may never recover.
When a forest is completely destroyed by an intense fire, nothing but charred tree-trunks for miles, there are no survivors spreading seeds to start the ecosystem on a path to recovery. Especially in the arid southwest, forests that established and thrived under wetter climate conditions may not be able to re-establish, and shrub or grasslands may move in to take their places. (More from NPR)
When the formerly dominant species struggle to re-establish after a fire, something else will take its place. Unfortunately, in many places the species best equipped to take advantage of a dramatically disturbed landscape are invasive species. In the Mojave and Great Basin deserts, exotic annual grasses often take over burned areas and create a continuous carpet of grass, dead and dry by mid-summer, to fuel the next fire. Scientists call this spiral of ecosystem damage the grass-fire cycle.
Some ecosystems may never be able to fully recover, but that doesn t mean scientists and land managers aren t trying to encourage restoration. A federal program, the Emergency Stabilization and Rehabilitation program, funds projects to protect the landscape in the aftermath of a fire. Goals include minimizing soil erosion that could damage watersheds and reducing the establishment of invasive species. The program isn t designed to meet long term restoration goals, but rather to meet the immediate need of preventing further damage after a fire.
In ecosystems that are not strongly adapted to fire, one such project is applying seeds of a native species to a burned landscape, to encourage rapid recovery of native species and reduce the opportunity for weeds to invade. In some cases, these expensive treatments succeed, and in others, they fail. The ESR program doesn t fund research projects on restoration, only the actual treatments and subsequent monitoring to measure treatment effectiveness. (Disclaimer- I used to work as a field tech on one of these monitoring projects in Nevada).
In ecosystems where fires are common, and necessary, restoration research was less critical. The fire itself can catalyze the ecosystem s re-growth. But, since recent years have seen more wildfires devastating ecosystems where fire was historically rare and more intense wildfires doing unprecedented damage in forests adapted to less intense fire, more research is severely needed to understand the implications of our changing fire regimes.
Wildfires did a lot of damage this year, 2011 too. Scientists are just getting started on investigating the impacts of some of these mega-fires. 2006 was the worst year on record, and while some of those burns are healing and growing back, others were covered by invasive species, and burned again just a few years later. There s no simple solution to these problems, preventing fires in the first place led, in part, to our current mess. Removing the accumulating fuels can lead to lower intensity fires in the future, but those treatments are labor intensive and expensive. Post fire projects like seeding treatments, soil stabilization, and invasive species management are expensive too, on top of the costs of keeping fires away from communities and lost natural resources. With that in mind, fuel reduction may be long term cost effective, especially with continued climate risks for fire.
Every summer, fires make the news. This summer, the connections between climate and fire finally made it into mainstream coverage, some, but not enough. Maybe by next summer, we ll be talking about restoration and fuel reduction and ultimately how to save some of our western forests from the fires of the future.