In today’s Academic Minute, Dr. Wally Covington of Northern Arizona University explains why the forests of the American West have become more susceptible to large fires and outlines efforts to restore their natural ecology.
Wally Covington is Regents’ Professor and Director of the Ecological Restoration Institute at Northern Arizona University. He has received national and international recognition for his work in forest ecosystem health, restoration ecology, and fire effects on forest ecosystems. He holds a Ph.D. in applied forest ecosystem analysis from Yale University.
Dr. W. Wallace Covington – Wildfires and Forest Restoration
One of today’s greatest conservation challenges is the decline of forests that evolved with frequent, low intensity surface fires. These forests now burn with high intensity crown fires on a scale of half million acres, an area half the size of Long Island. We are seeing these changes throughout dry forests of the West. The outlook is grim. Climate change is bringing extreme droughts and high winds, both of which exacerbate the problem.
These landscapes were once dominated by open, park-like forests, kept open by naturally occurring, frequent surface fires. That all changed with Euro-American settlement and the introduction of heavy livestock grazing. Grazing removed the grass across vast landscapes, effectively eliminating natural fires.
In the absence of these fires, tree populations irrupted to levels far beyond the carrying capacity of the land. Natural fire regimes once limited tree densities at 10 to 60 trees per acre. Today, 500 to 1000 trees per acre is the norm. These excessive tree densities have shifted the role of fire from maintaining forest health, to a destructive force that can impair ecosystems for centuries.
All is not lost. For example, in Arizona the 4 Forest Restoration Initiative is working to restore 2.4 million acres that stretches from the Grand Canyon to the New Mexico border. Other landscape restoration efforts are spreading throughout the West. Today many of us are optimistic about getting on top of this problem. If we are successful, future generations will have healthy forests that are an asset, instead of a liability.