The Beginnings of the Fire Suppression Fallacy

– How Truth Metastasized Into A Lie – The Fire Suppression Fallacy –
(Part IV)

How did the observation that fire suppression has caused some forests to miss several natural fire cycles metastasize into a pernicious stereotype that has convinced huge numbers of people that Nature is sick, clogged with dead trees and unhealthy vegetation, and is ready to vaporize in the next wildfire?

As is the case with fear-mongering media outlets, catastrophizing even the most insignificant events to obtain attention, images and situations are cherry-picked by proponents of the fire suppression fallacy to communicate the most dire circumstance. The propaganda has been incredibly successful, convincing politicians to allocate billions of dollars to “fix” Nature with grinding machines, chainsaws, and herbicide.

As with most stories designed to panic, the truth becomes embellished and inconvenient facts are ignored or forgotten.

Photo: A selected scene to convey the most dire circumstance; was it cherry-picked or a fair representation? This image was shown at a recent conservation conference in San Diego County to support the notion that the forests in the region’s eastern mountains are sick, “dog-haired” thickets in need of immediate treatment. Looking carefully through the trees in the foreground, green trees can be seen. Also, notice how the tops of the trees in the foreground are not shown in the frame. Some, perhaps even most of these trees are not dead. In denser pockets like this it is common for trees to self-prune their lower and middle branches, especially during droughts, since those branches receive far less sunlight and on a per-needle basis, needles in the lower and middle canopy are significantly less photosynthetically productive. Look closely at the upper right. Green foliage can be seen atop one of the mature trees in the foreground that is ostensibly dead. If the image had been expanded slightly to include the tree tops, would green crowns appear on some or most of the trees? Regardless, drought has killed groups of trees in forests for millions of years. It is a natural event that a multitude of organisms take advantage of, from nest cavity birds, to insects, to fungi. Unfortunately, the actual location shown in the image was not identified, although the presence of what appear to be invasive weeds indicate this may have been a previously disturbed site.

Photos: More typical forest scenes in the mountains of eastern San Diego County. L) An image selected to represent the average forest composition. R) A mixed conifer/oak/chaparral community with an open meadow/ranch land in the background. Location: Laguna Mountains, Cleveland National Forest.

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The origins of the fire suppression fallacy can be traced back to the late 1800’s when westward expansion brought more human beings, and hence sources of ignition, into a highly flammable environment. Vast piles of logging slash (limbs and other waste from timber operations), hot cinders from trains traveling deep into the back country, unattended fires utilized to clear land, outright carelessness (Pyne 1982), and most importantly drought and high winds, all played a role in adding more, larger fires to the landscape. Between 1865 and 1910 large wildfires from the Great Lakes region to California led federal and state governments to form cooperative firefighting agreements and pass regulations attempting to reduce the likelihood of human caused ignitions and fight fires when they started.

Many of these fires, such as the 1871 Peshtigo fire in Wisconsin, which killed an estimated 1,500 people, were linked to piles of logging slash. Such slash-related forest fires continued into the early 1900’s, due to the deadly combination of loggers resisting change in their practices (McMahon and Karamanski 2002) and severe fire weather. As a reminder, these huge, high-intensity wildfires burned prior to the era of fire suppression (Table 1).

Year	Fire Name	Location	Acres burned	Deaths
1825	Miramichi/Maine	New Brunswick/Maine	3,000,000	160
1846	Yaquina	Oregon	484,000	?
1848	Nestucca	Oregon	320,000	?
1849	Siletz	Oregon	800,000	?
1865	Silverton	Oregon	1,000,000	?
1868	Coos	Oregon	300,000	?
1870	The Great Fire	Santa Rosa, California	>40,000 est.	?
1871	Peshtigo	Wisconsin/Michigan	3,780,000 est.	Up to 1,500
1876	Bighorn	Wyoming	500,000	?
1878	Tujunga Cañon	Los Angeles Co, California	59,550	?
1881	Thumb	Michigan	1,000,000	282 est.
1889	Poway	San Diego Co, California	>60,000 est.	2?
1889	Santiago Canyon	Orange/Riverside/San Diego Co, California	>300,000 est.	?
1894	Hinckley	Minnesota	160,000	418
1894	Wisconsin	Wisconsin	1,400,000 est.	?
1902	Yacoult	Washington/Oregon	1,000,000	38
1903	Adirondack	New York	637,000	?
1910	The Great Fire	Idaho/Montana	3,000,000	85
1918	Cloquet-Moose Lake	Minnesota	250,000	450

Table 1: Large wildfires between 1825 and 1918. Contrary to current media stories and breathless commentary about wildfires, the newly minted “megafires” are nothing new in North America. If fire suppression impacts are responsible for the size and intensity of wildfires, why did such large fires occur long before the era of fire suppression?

Wildfires caused by human activity were certainly not limited to forests. According to an early Forest Service bulletin, the purposeful ignition of chaparral covered hillsides in Southern California was also a significant problem. “Some prospectors would burn over the region which they intended to explore. If a hunter wished to start a fire to drive out a wounded deer, no one objected” (Plummer 1911). Although the causes are unknown, in late September, 1889, more than an estimated 360,000 acres burned during two different fires in Orange and San Diego Counties (Barrett 1935, Keeley and Zedler 2009). For comparison, the 2003 San Diego County Cedar fire burned 273,246 acres.

The federal government’s desire to protect forests and other valuable watersheds from wildfires was one of the main reasons the first fifteen National Forest Reserves were established by President Benjamin Harrison in 1891, renamed National Forests by the Fulton Amendment in 1907. The amendment also prohibited further designation of national forests land in much of the West without an act of Congress. Just before the new law took effect, however, President Theodore Roosevelt established more than 16 million acres of forest reserve land within six western states, known as the “Midnight Reserves” for the nature of their last minute creation – a nifty sleight of hand that we should be forever grateful.

The federal government’s first significant fire suppression effort occurred in Yellowstone National Park by the U.S. Army during the Bunsen Peak Fire in 1886 (Allin 2006). After the Great Fire of 1910, where more than three million acres burned in Idaho and Montana killing eighty-five people, the fledgling United States Forest Service initiated a widespread effort to suppress all wildfires within the National Forest system (Pyne 1982). A cooling trend in the West between 1945 and 1980 helped considerably.

The Leopold Report

Although the wisdom of complete fire suppression was questioned from the very beginning by those who saw fire in forests as an important natural process (Benedict 1930), the official policy remained relatively unchanged until after the release of the Leopold Report in 1963 (named for the lead author, A. Starker Leopold, brother of the famous conservationist, Aldo Leopold). The report, officially titled “Wildlife Management in the National Parks,” correctly noted that most natural communities are dynamic systems in a constant state of change with fire, floods, and insect outbreaks playing pivotal roles. It advocated for allowing such natural forces to return in a managed way in national parks, in particular fire, to recreate conditions that were assumed to prevail prior to European settlement.

Photo: A. Starker Leopold. University of California.

The call to allow Nature to play its natural role in national parks was a welcome one, based on science. Unfortunately, in an apparent attempt to support their conclusions, the authors of the Report departed from proven ecological principles and repeated anecdotal descriptions of forests that have since been shown to be a selective use of evidence. Without any attempt to objectively analyze what was written by whom, where, and why, the authors stated that,

“When the forty-niners poured over the Sierra Nevada into California, those that kept diaries spoke almost to a man of the wide-spaced columns of mature trees that grew on the lower western slope in gigantic magnificence. The ground was a grass parkland, in springtime carpeted with wildflowers. Deer and bears were abundant.“

While such descriptions exist, they paint a biased image. Humans have a habit of seeing what they can describe, or what is preferred, rather than describing everything they see. In a thorough paper on historical forest structure and fire in the Sierra Nevada, Baker (2014) concluded,

“Thus, tree-ring reconstructions, early scientific reports, and the GLO (General Land Office) reconstructions concur that historical SMC (Sierra Mixed Conifer) forests were dense to very dense on average, not on average open and park-like as in the main view in the introduction. Somewhat open, park-like forests with 150 trees/hectare did occur, but only on 23% of the northern and 33% of the southern Sierra Nevada.”

The Leopold Report followed its pastoral description of early forests as being open and park-like with a general condemnation of the present condition of the western Sierra Nevada.

“Today much of the west slope is a dog-hair thicket of young pines, white fir, incense cedar, and mature brush–a direct function of overprotection from natural ground fires. Within the four national parks–Lassen, Yosemite, Sequoia, and Kings Canyon–the thickets are even more impenetrable than elsewhere. Not only is this accumulation of fuel dangerous to the giant sequoias’ and other mature trees but the animal life is meager, wildflowers are sparse, and to some at least the vegetative tangle is depressing, not uplifting.”

Since the Report was based on anecdotal experiences and the collective thinking of several individuals after visiting America’s national parks, it is impossible to evaluate how the authors came to the conclusion that the western Sierra Nevada, from its granite crests to the valley foothills, was covered in malignant tangles of depressing, dog-hair thickets, all the result of past fire suppression. However, the available research at the time (and the anecdotal experiences of this writer during his dozens of backpacking trips in the western Sierra from the 1970s onward) fail to support such a bleak picture.

There are more than ten distinctly different types of tree-dominated ecosystems in the western Sierra Nevada, each with varying natural fire regimes, species composition, and structure. From sparse subalpine forests to dense lodgepole pine forests, and significant stands of naturally impenetrable chaparral throughout, the diversity of these ecosystems and the tree species therein is vast and complex.

Photos: “Depressing, dog-hair thickets” nowhere to be found. Forests in Wilderness/national park areas on the western slope of the Sierra Nevada near Cedar Grove, California. Clockwise from upper left: 1) Old-growth pines. 2) Old-growth manzanita chaparral surrounded by pines and junipers. 3) Sparse sub-Alpine forests near Colby Pass. 4) Open Jeffrey pine grove. 5) Dense lodgepole pine forest immediately adjacent the open Jeffrey pine grove. 6) Native rhododendrons in bloom within California’s northernmost grove of Sequoias in the Tahoe National Forest.

Interestingly, the Leopold report did acknowledge the significant role years of mining, logging, overgrazing, and human-caused wildfires played in severely altering the landscape. But the report failed to make the connection between those activities and the dense forest conditions the authors may have observed in some locations.

Rather than being the result of “overprotection from natural ground fires,” much of the dense nature of forested areas in California is due to the second or third growth created by removal of the forest canopy through intensive logging operations. A similar conclusion has been reached concerning the impact of overgrazing by sheep and repeated burning by sheep herders in California (McKelvey and Johnston 1992). In a 1902 USGS report on the northern Sierra, John B. Leiberg indicated that a “third of the forest had been cut over and that most of the forest had a heavy undergrowth of brush.”  Concerning the central Sierra Nevada, the USGS report stated there was, “widespread damage to soil, water, meadows and forests due to heavy cattle and sheep grazing and decades of repeated fires” (Sudworth 1900). In a particularly vivid description, the Acting Superintendent of Sequoia and General Grant National Parks said, “The soil being denuded of grass is broken up by thousands of sheep tracks, and when the rains come this loose soil is washed down the mountainsides into the valleys, covering up the swamps and meadows, destroying these natural reservoirs” (Vankat 1970).

Why the Leopold Report authors laid complete blame on past fire suppression for the forest conditions they claimed were everywhere in the western Sierra, ignoring the historic role played by early settlers and the timber industry in setting the stage for the growth of dense forests, is unknown. However, the characterization has stuck. Today, it is nearly impossible to find a media article or agency report that does not characterize nearly every wildland, forest or not, as being dangerously overgrown, a product of past fire suppression by misguided government wildland firefighters charged with saving lives and property.

The Leopold Report laid the foundation of the fire suppression fallacy by mischaracterizing the extent and impact of our efforts to suppress fire.

While the 1963 Leopold Report had tremendous influence in changing the way land managers viewed fire, it took time for its recommendations to be applied to the landscape. Although the National Park Service (NPS) allowed some burning to occur in Everglades National Park and conducted a few experimental burns in California’s sequoia groves during the 1950’s, it wasn’t until 1968 in the Sequoia-Kings Canyon National Park that the NPS initiated a significant effort to allow fire to play a more natural role in ecosystem processes. The Forest Service soon followed in 1972 by permitting a lightning-caused fire to burn in the Selway-Bitteroot Wilderness (Carle 2002).

“We were a pretty lonely bunch back then,” Don Despain said about the few public land managers who were letting selected fires burn without suppression. We met Don for lunch during a fire ecology conference in Portland in 2006 and talked about his efforts to convince agencies to let it play its natural role again. “Les Gunzel from Saguaro National Monument, Bob Mutch from the Selway Bitterroot Wilderness, and Bruce Kilgore from Everglades National Park, and I got together in Missoula in 1972 to discuss our ideas about how to let fires run naturally. There was a lot of institutional fear and resistance.”

The Impact of Fire Suppression

The success of fire suppression efforts in the West over the past century, facilitated by climatic conditions conducive to suppression, has varied greatly depending upon the ecosystem involved. Dry ponderosa pine forests in the Southwest with frequent lightning-caused ignitions have been estimated to have burned at 4 – 36-year intervals prior to fire suppression efforts (Swetnam and Baisan 1996). A similar condition may exist in some of the ponderosa-Jeffrey pine forests covering the western slopes of the Sierra Nevada (Caprio and Swetnam 1995).

However, natural fire regimes in most of the West’s forests and native shrublands, have not been significantly altered by fire suppression activities – their natural fire return intervals are in excess of the time since fire suppression efforts became relatively successful (Table 2).

For example, subalpine forests of lodgepole pine in and around Yellowstone National Park have been shaped by naturally occurring, high-severity, stand-replacing crown fires every 300-400 years (Romme 1982). Fire return intervals in excess of 200 years occur in western hemlock-Douglas fir forests in the Pacific Northwest (Agee 1993).

Photo: Lodgepole pine forest in Yellowstone National Park. Although there is a tremendous amount of “fuel” in this dense forest, the condition is perfectly natural. It is not the result of fire exclusion.

It is important to point out that it is not always easy to determine natural fire regimes based on species mix alone because variations are often found within the same forest type. This can be seen for western larch-lodgepole pine forests in the southwestern portion of Glacier National Park where high-severity, stand-replacing crown fires with mean intervals of 140 – 340 years are the normal pattern. Six kilometers to the northeast, a mixed-severity fire regime with mean intervals of 25-75 years appears to predominate (Barrett, et al. 1991).

Plant Community	Approximate acres in Western US	Estimated natural fire return interval in years	Fire interval source
Sagebrush steppe Ferry et al. 1995.	112 million	325-450 years: low sagebrush 100-240 years: Wyoming big sagebrush 70-200 years: mountain big sagebrush	Baker 2006.
Mojave desert MacMahon 2000.	34.5 million	Extremely rare (low elevations) to uncommon elsewhere.	Humphrey 1974, Underwood et al. 2019.
Sonoran desert W.H. McNab 1994.	24.7 million	Extremely rare due to lack of fuel, but invasive weeds are now allowing fires to spread.	Aslan et al. 2020.
Lodgepole pine forest. Alig and Butler 2004.	14.6 million (Rocky Mts.)	135-185 yrs: Yellowstone low elevations 280-310 yrs: Yellowstone high elevations	Schoennagel et al. 2003.
Pinon-Juniper woodlands. West 1999.	74 million	400 years or more (Mesa Verde)	Floyd et al. 2004.
California chaparral. Jones and Stokes 1987.	8.6 million	30- 150 years or more. Higher range at lower elevations.	Halsey and Keeley 2016.
Fir-spruce forest. Alig and Butler 2004.	19 million (Rocky Mts.)	300 years or more (Colorado)	Benson and Green 1987.

Table 2: Natural Fire Return Intervals in Various Plant Communities.

Despite such differences in fire regimes between and within various types of forests, the viewpoint that fire suppression has been responsible for creating unnatural fuel loads throughout the West dominates public discourse about wildland fire management, regardless of ecosystem type.

Symbolic of this mindset, Secretary of the Interior Bruce Babbitt wrote in 1995 that, “the vast majority of western public lands – including rangelands, chaparral, and ponderosa forests – burned historically every 10 to 50 years.” Babbitt’s statement was wildly inaccurate not only because the numbers are wrong, but it over simplifies the complexity of fire regimes. In line with the fire suppression fallacy, Babbitt left the impression that we need to lay more fire on the ground across the West when in fact a significant number of ecosystems, especially chaparral, are suffering because of too much fire.

Babbitt’s words are nearly identical to what one hears today with the exception to chaparral. Most agencies recognize that chaparral is now being threatened by too much fire, rather than not enough.

The Impact of Missed Fire Cycles

There is a fierce debate concerning the biological impact of fire suppression on forests.

One narrative, in line with the Leopold Report, is that understory shrubs and small trees begin to accumulate due to a lack of fire. This accumulation in turn is blamed for increasing the occurrence and size of high-severity crown fires by facilitating the spread of flames into the forest canopy (Agee 1993, Covington and Moore 1994, Smith and Arno 1999). This was the narrative underlying the passage of the 2004 Healthy Forest Restoration Act (HFRA) – forests were deemed “unhealthy” because past fire suppression had allowed the accumulation of “hazardous fuels.”

Under the HFRA, forest type and natural fire return intervals are supposed to be considered in determining if a forest is in fact “unhealthy” (a term that was never defined). In practice, however, all understory habitat and trees without merchantable value are often seen as hazardous fuels in need of removal, no matter where they occur.

This narrative is compelling because it is based on the initial truth: the lack of natural fire has impacted some forests, facilitating understory growth. The narrative also seems to make intuitive sense. After all, the more wood one throws in the fireplace, the bigger the fire, right?

The problem with intuition like this is that it is based largely on anecdotal experience – a fire in a hearth is not subject to all the variables that cause wildfire behavior to become so wildly unpredictable.

The amount of burnable material available does not determine fire size, severity, or occurrence of wildfires in Nature. Deep, dense forests in the Pacific Northwest rarely burn despite downed trees, nearly impenetrable vegetation, and thick layers of leaf litter – there’s just too much moisture.

Large wildfires nearly always occur when the landscape is parched by drought, and subject to low humidity and wind. Wildfire spread is also facilitated by flammable, non-native grasses that are spread by logging/habitat clearance operations. Counter-intuitively, wildfires in old, dense forests and Wilderness areas where logging and clearance are not allowed, usually burn with much less severity than forests that have been heavily managed (Bradley et al. 2016, Odion and Hanson 2006, Odion et al. 2004).

“We investigated the relationship between protected status and fire severity using the Random Forests algorithm applied to 1500 fires affecting 9.5 million hectares between 1984 and 2014 in pine (Pinus ponderosa, Pinus jeffreyi) and mixed-conifer forests of western United States, accounting for key topographic and climate variables. We found forests with higher levels of protection [from logging] had lower severity values even though they are generally identified as having the highest overall levels of biomass and fuel loading.”

Bradley et. al 2016

The fire suppression fallacy has provided politicians an easy way to appear as if they are “doing” something about wildfires and climate change. As a consequence, billions of dollars have been allocated to log forests and clear native shrublands throughout California and the West, all in the name of “ecological restoration.”

Orwellian doublespeak is utilized often by fire suppression fallacy devotees.

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Part V coming soon: It’s Life, Not Biomass.
Are dense forests, dead trees, and “brushfields” really that horrible? Are forests really being destroyed by wildfires? Is “bombing” the forest to save the forest, Vietnam redux?

Part I: The Fire Suppression Fallacy
Part II: Chainsaw Medicine is Not the Answer
Part III: Landmark Study Finds Pattern of “Falsification of the Scientific Record” in Government-Funded Wildfire Studies

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