July 12, 2013 | Article
Climate change has made our forests hotter and drier. Once you accept that, what do you do next?
Wildfires can take light unexpectedly and fiercely. With stunning frequency they threaten communities, scar national forests, and wreak havoc across our Western landscape for decades afterwards.
But it doesn’t have to be this way. At least not this bad, says Scott Abella.
Abella has made it his life’s work to understand how fires occur in Western forests. He has devised ways to prevent undesired, severe fires and championed programs to help forests recover. An affiliate UNLV research professor, Abella travels throughout the West each summer to study firsthand the devastation that wildfires deliver. As he puts it, fires will always happen, but steps can be taken to reduce their severity.
We caught up with Abella to learn more about what’s causing mega fires in the West.
Many forests in the West, over evolutionary time, adapted and became accustomed to frequent, low-intensity surface fires that usually only burned along the ground. Under natural conditions, small surface fires kept forests in check, recycled nutrients, and prevented the accumulation of the fuel that feeds the massive wildfires.
But in the last century, preventing fires in these ‘frequent fire’ forests resulted in much thicker tree cover and ballooning populations. It’s similar to how deer populations exploded when their predators were eliminated in national forests.
So, if a forest burned naturally every five years before 1900, the past 110 years of fire suppression means the forest has ‘missed’ 22 fires.
Nevada’s forests are located on more than 300 isolated mountain ranges, many with desert in between. Though Nevada might not have a mega fire — on the order of 500,000 acres like we’ve seen in Colorado, New Mexico, and Arizona — we could lose a forest on an entire mountain range in a single fire. It’s important to remember that while Mount Charleston seems green to us, the forest is still within the Mojave Desert – the driest desert in North America. A key point is that the ponderosa pine forests of Mount Charleston are not adapted to these types of severe fires.
Fires affect the entire landscape, not just the mountains. Our deserts have a major fire problem because nonnative grasses, like cheatgrass, have become well established and provide fuel for fires caused by humans and lightning strikes. As a result, fires are now starting in the desert and burning into the forest.
The current focus is on the safety of firefighters and citizens, and limiting ecological damage by stopping the Carpenter Fire currently burning at Mt. Charleston. When the fire is out, several preventive measures can limit soil erosion and help promote forest recovery.
Soil 'covers' like straw, mulches, or woody debris can be placed on the soil to help protect the soil. Obtaining enough seed for native plants is challenging, but seeding or planting native plants and trees can become a long-term goal for the burned areas.
To protect remaining forest areas, our best hope is to start large, collaborative landscape-scale projects with tree thinning and careful, strategic reintroduction of fire. An example for thinning is mimicking natural forest patterns like clumping of trees. This will reduce density and the accumulation of fuel sources, including pine needles, twigs, branches and logs. Some of this is already happening in the Spring Mountains outside Las Vegas.
Fires will continue to occur, through both human causes and lightning, and that’s actually fine. What we can control are the fuel conditions present when a wildfire starts.
Fires have previously occurred in the Spring Mountains, but diligent fire suppression and careful evacuation of people from their homes and recreation sites have limited the damage. But prevailing fire suppression practices will make it hard to prevent additional large fires in the future. Even if the fires are relatively small, they can nickel-and-dime the forest to the point that in 20 years, we realize very little forest is left.
It is hard to predict forest recovery time from fires like this because it depends on how much soil is lost through erosion, whether or not some trees are left to provide seed, and whether future climates are conducive to tree recruitment.
Re-establishment of trees after these types of fires elsewhere has required many decades to centuries.
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