Summer's approaching, and so is forest fire season. In the Summer of 2012, many wildfires around the country burned out of control due to above average temperatures and low rainfall across the nation.
The fact that many U.S. forests are overgrown has also played a part in how hot and fast forest fires burn.
Why do forests get overgrown? Isn't this a natural process? How does this truly affect forest fires, and is forest conservation policy to blame?
Dr. Karen Clark, of Albuquerque, NM, writes: Reporters and media use the term "overgrowth" when describing why forest fires are so intense. How can a forest become naturally overgrown? Isn't there carrying capacity in all ecosystems that would prevent this from occurring? Hasn't the term 'overgrowth' been used to excuse deforestation policies?
Chris Topik, Director of Restoring America’s Forests for The Nature Conservancy, responds:
The carrying capacity of ecosystems depends on the productive potential of the site (things like moisture and soil types), and also processes that govern life and development of vegetation and trees. One of these major processes is fire. Many of our forests here in the United States actually need fire as much as they need water; fire warms pine cones so they can release seeds, and many trees have grown dense bark to insulate themselves from fires that eliminates other tree competitors (thus providing more light, water, and soil to our native fire-adapted trees).
But for most of the 20th century we sought to restrain natural, low-intensity fires that historically helped clear out forests and prevented them from being overgrown. A century of this “fire suppression” policy has resulted in extremely overgrown forests, where too much woody fuel has built up, and not enough light is hitting the forest floor to nourish a wide diversity of plants— this is bad for people, water, and wildlife.
The result of this outdated policy is pretty clear today: 57% more acres in the United States have burned over the last decade than the previous four decades’ average. Stated another way, we’ve only had three years since 1960 where more than 9 million acres have burned; all three have come since 2006 (including last year). The severity of these fires has created a new term this century—“megafire”.
Rather than just clear out forests of undergrowth as they had in the past, today’s intense megafires incinerate entire forests, leaving completely sterilized soils and ash where no tree is left surviving. Sometimes this remaining ash gets washed out into our water supply, and sludges over our reservoirs (as half of the U.S.’s water comes from our forested lands).
Certainly the clear documented trend of warming temperatures and increasing drought, particularly in the Southwest, is also contributing to this perfect storm of megafires.
Our challenge today is figuring out how to respond to these existing conditions. A passive approach would be to let the forests continue to become unhealthy, allow megafires to develop, put firefighters and communities at risk in trying to react to megafires, and then deal with the expensive and undesirable outcome of incinerated lands.
Another more proactive approach, which The Nature Conservancy’s Restoring America’s Forests program is pursuing with our many great partners (including the country’s largest single manager of forest land, the U.S. Forest Service), is to pre-treat our forests with controlled burning and thinning. These actions reducing the risk of destructive and expensive megafires, improve water security, provide jobs, support wildlife habitat, and keep our forests healthy. Investing in proactive forest restoration is not only safer, but cheaper.
Our nation’s forests are part of who we are. They support our lives, livelihoods, and the wildlife we share this country with. We believe by helping our forests become healthier, we are making our nation healthier.