Posted by: chrismaser | June 20, 2011



Fire is a biophysical process through which Nature originally designed forests and grasslands throughout much of the United States and Canada.1 But, having been trained in British colonial forestry in France, that’s not how Gifford Pinchot, first chief of the U.S. Forest Service, saw it as he rode through park-like stands of ponderosa pine along the Mogollon Rim of central Arizona in the year 1900.

It was a fine day in June as Pinchot rode his horse to the edge of a bluff overlooking the largest, continuous ponderosa pine forest in North America. It was warm, and everything seemed flammable. Even the pine-scented air seemed ready to burn. What a sight! Sitting on a horse in a sun-dappled, perfumed forest without a logging road to scar the ground, without a chain saw to tear the silence, to simply behold such a forest.

“We looked down and across the forest to the plain,” he wrote years later. “And as we looked there rose a line of smokes. An Apache was getting ready to hunt deer. And he was setting the woods on fire because a hunter has a better chance under cover of smoke. It was primeval but not according to the rules.” 2 [Emphasis mine]

The forest over which Pinchot gazed on that June day in 1900 was 300 to 400 hundred or more years old, with trees that had germinated and grown throughout their lives in a regime characterized by low-intensity, surface fires sweeping repeatedly through their understory. These fires, occurring every few years or so, consumed dead branches, stems, and needles on the ground and thinned clumps of seedlings growing in openings left by vanquished trees. Although fire had been a major architect of the park-like forest of stately pines that Pinchot admired, he didn’t understand fire’s significance in designing the forest or the indigenous peoples’ role in perpetuating them.

I spent part of October, 2002, looking at fires that burned that summer, six years ago, 36 years ago, and 120 years ago. Each fire, no matter how intense, left almost all trees standing, even those that were only three inches in diameter. In addition to the wonderful diversity of habitats that a single fire creates within a given area, successive fires over variable years compound the vast mosaics of interconnected macro- and micro-habitats as they design and redesign landscape-scale patterns over decades and centuries, creating patterns that are readily discernible on aerial photographs. In so doing, fires maintain and revitalize ecological diversity and thus ameliorate many of our concerns about the ecological integrity (= health) of our nation’s forests and grasslands.

While we have progressed much in our understanding of Nature through the intellectual pursuit of science, we have lost much of our connection with Nature through our incessant focus on the competitive “money chase.” We seem most often to view Nature as something to conquer and control. Our fear of Nature causes us to isolate a point on the continuum of change (such as a tract of ancient forest), draw an illusionary line around it, quantify its commercial value, and define it as an independent entity in time and space—thereby denying its relationship as part of a functional whole.

An independent variable and a dynamic relationship are mutually exclusive; in addition to which, everything in the universe is part of a single, dynamic relationship. Moreover, it is both arrogant and unwise to demand from Nature what Nature is not designed to give. A forest, savannah, or grassland can thus be summed up as a continuum of causes and effects that may appear randomly unpredictable in the short term, yet dynamically organized in time and space in the long term. However, we forfeit our understanding and any predictability of the trends Nature has provided as long as we blindly commit ourselves to dealing in terms of artificially conjured, variables-du-jour based on potential economic gain.

Given enough time without human intervention, ecosystems evolve inevitably toward a critical state in which a minor event sooner or later leads to a major event that alters the ecosystem in some way. Thus, as a temperate forest grows old, it converts energy from the sun into living tissue, which collects on the forest floor. There, through decomposition, the organic debris releases the energy stored in its dead tissue. Similarly, a forest—like every ecosystem—is a dissipative system in that energy acquired from the sun is dissipated gradually through decomposition or rapidly through fire.

Rates of decomposition vary of course. A leaf rots quickly and releases its stored energy rapidly, whereas wood rots much more slowly, often over centuries. As wood accumulates, so does energy stored in its fibers. Before suppression, fires burned frequently enough to generally control the amount of energy stored in accumulating dead wood by burning it up, thus protecting a forest for decades, even centuries, from a catastrophic fire that started the forest over.

In this way, a 700-year-old forest that burned could be replaced by another, albeit different, 700-year-old forest on the same acreage, which mean, despite a series of fires, a forest ecosystem could remain a forest ecosystem. So it is that forests throughout most of North America have been evolving from one intense fire to the next, from one critical state to the next.

Whereas Pinchot knew about fire, he was convinced it had no place in a “managed forest.” Managed in this sense, means “under human control.” Fire was to be vigorously extinguished, therefore, because conventional wisdom dictated that ground fires kept forests “understocked,” and more trees could be grown and harvested in the absence of fire. In addition, fires often scarred the surviving trees, like the ones Pinchot had seen in Arizona, and this kind of injury allowed decay-causing fungi to enter the stem, thus reducing the quantity and quality of harvestable wood. Finally, any wood not used for direct human benefit was—and is—considered an economic waste.

That notwithstanding, Sunset Magazine contained an article in 1910—a mere decade after Pinchot’s ride on the Mogollon Rim—that recommended the fledgling Forest Service use the Indigenous American’s method of setting “cool fires” in the spring and autumn to keep the forests open, consume accumulated fuel, and in so doing protected the forest from catastrophic fire.3 Unfortunately, that recommendation came the same year that, in the space of two days in “Hell,” fires raced across three million acres in Idaho and Montana, killing 85 firefighters, in what is called the “Big Blowup.” It would be a ten years after the Big Blowup before fires in Western forests and grasslands were effectively controlled.4

For decades thereafter, the U.S. Forest Service was dedicated to putting all fires out. By 1926, the objective was to control all fires before they grew to ten acres in size. And a decade later, the policy was to stop all fires by 10 a.m. on the second day.5 Such a policy is misplaced, however, because it ignores the primary cause of forest fires.

The response of the Forest Service is not surprising when one considers that most people prefer the devil they know to the devil they don’t, which is but saying that fighting the “terrible known” (an intense wildfire) is often more comfortable than the unknown (setting “cool fires” like the Indigenous Americans), even if the unknown promises to be better. People thus chart a course by consciously avoiding charting a course, which means that a manageable situation is neglected until it is thoroughly out of hand.

In Pinchot’s time and place in history, however, he was correct and on the cutting edge, and the ecological problems caused by such thinking were unbeknownst to him. Nevertheless, incorporation of these ideas into forestry have taken their toll. Only now, decades after the instigation of fire suppression, has the significance of changes in forest structure, composition, and function become evident.

For example, evidence shows that some ponderosa pine forests in northern Arizona had only 23 trees per acre in pre-settlement times. This pre-settlement density is in stark contrast to the current density of approximately 850 trees per acre, with predominantly small diameters.

The increase in density of trees is estimated to have caused: (1) a 92 percent drop in the production of grasses and forbs, (2) a 31 percent reduction in stream flow, (3) a 730 percent increase in accumulated fuels on the forest floor, (4) a 1700 percent increase in volume of saw timber, (5) a decrease from 115 to -8 in the index of scenic beauty, and (6) a shift in habitat from open, savannah-like conditions in pre-settlement times to dense forest.6

This increase in the density of trees may also result in the decreased vigor and increased mortality of all trees, especially those of the oldest age classes. Finally, the increased closure of the canopy, the vertical continuity of fuel in the form of trees in the understory (a fuel ladder), and the high loads of fuel on the ground result in a severe hazard of crown fires that will kill the forest. Such fires probably were exceedingly rare and localized in pre-settlement times, although ground fires were common before the settlers introduced grazing by domestic livestock and the Forest Service instituted fire suppression.

Only now—decades after Pinchot instigated the suppression of fire—has the significance of changes in the structure and composition of forests in many areas become evident. Since the advent of fire suppression, there has been a general increase in the number of trees and an increase in the amount of woody fuels on the forest floor. There has also been a decrease in the extent of quaking aspen (which often sprouts from roots following fire) and a corresponding increase in those species of trees that are more tolerant of the shaded conditions in closed-canopy forests. Some of these shade-tolerant trees have grown into the forest canopy and form a ladder up which a fire can burn from near the ground to the tops of large trees.

Although it is possible that climatic change could partially account for the increased number of large, so-called “wildfires,” alterations in forest composition and structure due to decades of fire suppression is the primary cause due to unchecked accumulations of woody fuels on the forest floor and to increasingly dense stands of young trees within the forests—both of which have come about since 1910.

Moreover, intensive study of historical fires has failed to document any cases of fire killing a forest by burning through treetops in the ponderosa pine forests of the American southwest prior to 1900. In contrast, however, increasingly intense fires have occurred since 1950—witness those of today.7

Because of the dynamic nature of evolving ecosystems and because each system is constantly organizing itself from one critical state to another, an ecosystem can only be “managed” for its possible evolution, not for an absolute value of anything, such as a given yield of products on a sustained basis. The only sustainability for which we can manipulate an ecosystem is whatever ensures its ability to adapt to evolutionary change (such as global warming) in a way that may be favorable for us.

Today, a major task facing scientists and “managers” is to re-educate themselves and the public. Smokey Bear (not to mention Walt Disney’s Bambi) has done a resounding job of convincing people that a forest fire or a grassland fire is terrible and wasteful. The new message must be that fires set by careless people can be needlessly destructive. On the other hand, fires under specific conditions are both beneficial and necessary to the long-term biophysical integrity and sustainability of our nation’s forests and grasslands in viable patterns at the scale of landscapes.

It now seems obvious that the effort to eliminate fire from forests and grasslands is an economic rule made by humans. The major obstacle to changing this rule is the illusional certainty of our knowledge, which fuels traditional economics while scientific understanding advances by slowly, uncertain increments and contradictions.

The challenge for today’s forestry and rangeland professionals and politicians is to sit humbly in the forest and grassland to discover the rules by which they have evolved and lived out the millennia. In fact, if the far-sighted Gifford Pinchot was alive today, knowing what we now know about fire, he would undoubtedly say, “Fire in managed forests is primeval and according to the rules. We must, therefore, learn all we can about its role in sustaining our nation’s forests for the benefit of the forests and our citizens through time and generations.”

And finally, every citizen who chooses to build within a forested area must take personal responsibility for implementing and maintaining the prescribed means of protecting their home from fire—and accept the risk of financial loss without expecting the public at large to bail them out through the payment of personal taxes.

Although it seems obvious that Nature’s fires are going to be less and less tolerated in future times due to objections from the growing human population,8 we must find a way to emulate the disturbance patterns whereby fire has created and maintained forests through time for the expressed reason that forest have become adapted to cope with the stresses of fire, and consequently are ill adapted to do without them.9 The purpose of this exercise would be to determine the common denominators and differences among the fire patterns and begin to figure out how various portions of a fire pattern, of even an entire fire pattern, could be emulated in caretaking the our nation’s forests without having to use fire per se on all acres all of the time. This said, however, both prescribed fire and letting some fires burn as Nature intended would be part of the caretaking strategy because fire is the most authentic emulation of itself.

While the literature leaves little doubt that fuels can be modified in ways that affect the behavior of fire, the best modification of fuels is with fire. A number of empirical studies demonstrate the effectiveness of prescribed fire in altering the behavior of “wildfires.” In terms of caretaking our public forest, therefore, it would be wise to locate areas in which fuels are modified in accord with well-constructed, experimentally driven designs that will provided the kind of knowledge necessary to emulate forest fires at an acceptable level of intensity and rate of spread for the sake of forest health and the maintenance of Nature’s ecological services—those required to sustain us as a human society.10

Related Posts:

• The Negotiability Of Constraints

• The Law Of Cosmic Unification

• Principle 4: All systems are defined by their function.

• Principle 5: All relationships result in a transfer of energy.

• Principle 7: All relationships have one or more tradeoffs.

• Principle 13: Systemic change is based on self-organized criticality.

• Why Make Life a Battlefield?

• Restoration Of A Specific Condition Is Not Possible


1. (1) Thomas.W. Swetnam. “Forest fire primeval.” Natural Science 3 (1988):236-241 and (2) Stephen J. Pyne. Fire in America: A Cultural History of Wildland and Rural Fire. University of Washington Press, Seattle, WA. 1997. 654 pp.

2. Pinchot, Gifford. Breaking new ground. Harcourt, Brace and Co., Inc., New York, NY. 1947. 522 pp.

3. George L. Hoxie. How fire helps forestry. Sunset 34 (1910):145-151.

4. (1) Stephen J. Pyne. Year of the fires: The story of the great fires of 1910. Viking Press, NY. 2001. and (2) Michael Williams. Americans & Their Forests: A Historical Geography. Cambridge University Press, New York, NY. 1989. 289 pp.

5. Tom Kenworthy. Prevention efforts still missing mark after 2 years and $6 billion. USA Today. August 22, 2002.

6. The preceding two paragraphs are based on: (1) Wally W. Covington and M.M. Moore. “Post-settlement changes in natural fire regimes and forest structure: Ecological restoration of old-growth ponderosa pine forests.” Journal of Sustainable Forestry 2 (1994):153-182; (2) Wally W. Covington and M.M. Moore. “Southwestern ponderosa pine forest structure: Changes since Euro-American settlement.” Journal of Forestry 92 (1994):39-47; (3) Wally W. Covington and M.M. Moore. 1991. Changes in forest conditions and multiresource yields from ponderosa pine forests since European settlement. Unpublished report., submitted to J. Keane, Water Resources Operations, Salt River Project, Phoenix, AZ. 50 pp.; and (4) Thomas.W. Swetnam. Fire history and climate in the southwestern United States. Pp. 6-17. In: Effects of Fire in Management of Southwestern Natural Resources. J. S. Krammers (Tech. Coord.). USDA Forest Service General Technical Report RM-191. Rocky Mt. Research Station, Fort Collins, CO. 1990.

7. (1) Randolph E. Schmid. Arizona Wildfires 2011: Part of New Era, With More Big Fires. Associated Press, June 15, 2011; (2) Wildfires From Arizona to Florida. Ferocious wildfires burn over a million acres of land, displacing thousands (June 17, 2011).; (3) Wildfires Fueled by Hot Weather and Dry Ground. Thousands of people were forced from their homes due to record breaking wildfire (June 18, 2011).; (4) Battling Blazes. Three dozen large fires are raging tonight in 10 states (June 18, 2011).; and (5) Wildfires Threaten Entire Cities in the West. Ryan Owens on the raging fires that have caused thousands to leave their homes (June 20, 2011).

8. Stephen J. Pyne. “The Political Ecology of Fire.” International Forest Fire News 19 (1998):2-4

9. James K. Agee. “The landscape ecology of western forest fire regimes.” Northwest Science 72(Special Issue) (1998):24-34.

10. (1) General Accounting Office (GAO). 1999. Western national forests: A cohesive strategy is needed to address catastrophic wildfire threats. U.S. General Accounting Office, House of Representatives, Committee on Resources, Report to the Subcommittee on Forests and Forest Health RCED-99-65. Washington, D.C. and (2) Henry Carey and Martha Schumann. 2003. Modifying Wildfire Behavior—The Effectiveness of Fuel Treatments. National Community Forestry Center, Southwest Region Working Paper 2. 26 pp

Text © by Chris Maser 2011. All rights reserved.

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