Dr. Craig Allen, a USGS research ecologist with the Midcontinent Ecological Science Center, is speaking of the New Mexico forest ecosystems he knows best, but his words apply equally well to most of western North America. "If you're trying to understand past and present patterns on the landscape," Allen says, "first of all you need to know something about fire."
From the northern Rocky Mountains to the Southwest borderlands, wildland fires have burned and rejuvenated western forests over the course of millennia. And forests are not the only environments affected by fire; to a greater or lesser degree, fire influences the structure and dynamics of nearly all of the West's terrestrial ecosystems. In some, such as the chaparral brushlands of California, fire has been a strong force guiding the evolution of local plant life, and a constant regulator of ecological communities. In many desert habitats, on the other hand, fires have been far less frequent, but represent a more severe disturbance when they do occur.
Scientists and managers increasingly recognize the importance of fire as a natural component of ecological systems. But while fire is often a beneficial process, it is always, in the short term, a destructive one. The presence of fire has usually been seen as incompatible with both human land-use practices and aesthetics, and for over a century fires have been actively suppressed throughout the West.
The negative consequences of forest fire suppression can now be clearly seen. In many areas, disruption of the natural fire regime has produced overcrowded forests with vast accumulations of dry fuel. Blazes that break out under these conditions may be far more destructive than the normal fires of centuries past and are often extremely difficult or impossible to control. The absence of a regular fire cycle has also harmed many plant and animal species whose life histories are tightly linked to fire d
Contact: Catherine Haecker
United States Geological Survey