Good Fire, Bad Fire

How to think about 

forest land management 

and ecological processes

Catamount Center for Geography

of the Southern Rockies
The first rule of tinkering is to save all the parts, according to forester, 

philosopher, and hunter Aldo Leopold. Leopold was thinking about 

wildfire 50 years ago when he also was questioning his own role in 

exterminating large predators, wondering how their removal might 

affect forest ecosystems in the future. Leopold was well ahead of his 

contemporaries in ecological thought. Like predators, fire cleans and 

regenerates the systems it touches. A generation later, we’re seeing the 

dramatic consequences of excluding fire from fire-adapted ecosystems.


When Colorado’s Hayman fire erupted on June 9, 2002, it did something no one had witnessed in the Front Range of the Rockies. The fire swept into a solid forest 

canopy of ponderosa pine and Douglas-fir and raced 19 miles in a single day, sending 

convection currents to 21,000 feet and sparking new blazes more than a mile ahead of 

its blistering front. Nothing like it had happened in Colorado’s recorded history. 

No amount of air support or ground attack could stop it. Fire crews could only get 

people out of the way. Fighters couldn’t contain the conflagration for the next 10 

days. When weather finally slowed the fire, it had touched 138,000 acres and set 

an ominous record: 60,000 acres of nearly total forest destruction. While smallerscale, stand-renewing fires appear throughout the tree-ring record in the southern 

Rocky Mountains, this was the worst known fire in at least 700 years.

Conditions were ripe. Rainfall had been well below normal for the previous 

four years, the result of a distant La Niña event in the southern Pacific. Relative 

humidity was about 5 percent and winds were 20 to 50 mph from a direction 

favoring rapid fire spread. But another factor that had nothing to do with the 

weather led to the blaze. The forest itself had built up to this for almost a century.

Consequences


That something was awry in the forest escaped notice for a long time, partly because the problem 

had more to do with what wasn’t happening. The forest had been operating for decades without all its 

systems intact, and the missing part was fire itself.

Without periodic fires the forest lost an important control mechanism, allowing excessive 

regeneration and a build-up of fuels beneath the forest overstory. Though obvious now, in the early 

1900s people saw wildfire as a destroyer of forests, a threat to human safety, and an unacceptable 

waste. That fire might serve as an integral part of the forest machine, preserving its health, assuring its 

future, protecting the quality of our air and water, was unimaginable in the new West. So the natural 

fire cycle as a regulatory system was often deliberately or indirectly altered—and the wonderfully 

complex, self-running, self-correcting forest machinery broke.

The story was much the same throughout fire-adapted ecosystems of the West. In 

the semi-arid grasslands, ranchers have viewed wildfire as the greatest single threat. 

A range fire’s appetite for grasses seemed surpassed only by that of the cattle. 

Fire threatened isolated houses and respected no property boundaries. Thus, 

every ranch became every other rancher’s concern and fire exclusion became 

the highest priority—a matter of economic survival. But range fires are an 

important part of the prairie machine too, and when they were removed 

the machine sputtered. Aggressive shrubs, held at bay by recurring fires 

of the distant past, encroached upon grasslands. Eastern red cedar moved 

westward, usurping resources that once belonged to the prairie, and soon 

ranchers were spending their money trying to eradicate the invasive plants.

The lessons sifted from the ashes of 2002 are obvious. When the 

Hayman fire went haywire in Colorado because the forest machine had ran 

too long without all its parts, it ended up costing 132 homes, $42 million in 

suppression efforts, and incalculable loss of opportunity. It is clear that our 

social and economic well-being depends upon maintaining our ecosystems and that 

disruption of self-regulating processes can be disastrous.

But we find ourselves now in a difficult position: that of having to manage complex 

landscapes without all the information we would like. We still don’t know much about nature’s 

regulatory processes, such as energy flows and nutrient cycling. Parts of the system interconnect in 

ways we cannot see or comprehend, and the functional roles of individual species are incompletely 

understood. As expressed by American ecologist Frank Egler, “Ecosystems are more complex than we 

think—they may be more complex than we can think.” Here, however, is where the words of Leopold 

ring like a hammer on steel:

The first rule of tinkering is to save all the parts.


Sidebar:  The Niobrara River-Nebraska Sandhills Region

The Niobrara River-Nebraska Sandhills region encompasses some 12 million 

acres of squelched slow-growing shrubs. The near elimination of wildfires in the 

last century has had many adverse effects including the accumulation of fuel 

hazards, changes in plant community composition, and lost range-management 

options. Ranchers now face far greater threats from fire than under previous 

natural conditions. In parts of northern Nebraska and southern South Dakota, 

ranchers have lost 60-70 percent of their productive rangeland to invading 

shrubs, translating into annual income losses of $20,000 or more for some.

More ranchers in the Niobrara-Sandhills region are learning the benefits of 

returning fire to its natural role, thereby reducing forage losses and tree 

invasion. Consequently, a 12-member partnership of landowners and other 

stakeholders formed to create a new fire management paradigm. The partnership 

includes private landowners and commercial businesses, eight rural fire districts 

in four counties, several state and federal government agencies, and the 

Nature Conservancy. They focus on education and regional fire management 

infrastructure, including the funding and retraining of volunteer fire fighters 

in the tools and techniques of prescribed burning. Though independent 

stakeholders often have diffferent land management objectives, partners have 

identified common ground in a desire for restored ecosystem integrity through 

improved wildfire management and appropriate use of prescribed burns. 

Common benefits include community protection from severe fires, improved 

productivity of ranch land, and greater protection of plant and animal species.


Fire as Process: Pre-settlement

Ablackened forest doesn’t appear to support much life, so fire exclusion might seem the first rule of saving all the parts. But the right kind of fire, as we have seen, helps 

maintain conditions necessary to support life. Certainly, in the short term, fire destroys many 

living organisms. But fire also creates opportunity. Plants and animals differ in their site 

requirements and competitive abilities. Many depend on the presence of openings in the 

existing plant cover to establish and complete their life cycles. Fire helps maintain a mosaic 

of habitat conditions in the landscape and thus preserves biodiversity. Just as diversity in 

an investment portfolio offers stability in the face of market fluctuations, diversity in nature 

is often the key to ecosystem stability and protection of rare or uncommon species. It is 

important to draw a distinction, however, between natural fire regimes and the altered fire 

behavior that we now witness.

What constitutes a “natural” fire regime? Much scientific probing has gone 

into answering this question. Through meticulous research, past forest conditions and 

fire histories have been reconstructed for some forest sites in the Colorado Front Range 

extending as far back as 1200 A.D. Detailed journals from early explorers, old photographs, 

historical forest inventories, logging records, and General Land Office surveys have all 

helped to piece together a picture of what our forests looked like when settlers arrived in the 

West. The greatest insights into past fire regimes have come from deciphering the permanent 

history of climate, forest fire, and insect outbreaks recorded in the annual growth rings of 

living and dead trees—the science of dendrochronology. By precisely dating fire scars in the 

tree-ring record and then mapping the locations 

of trees with scars of the same age, we gain an 

accurate picture of fire frequency and size in 

prehistorical times. Analyzing the age structure of 

old-growth stands in previously burned areas also 

reveals the severity of these fires, especially in 

areas that escaped earlier logging. Crown fires, for 

example, result in complete stand replacement and 

restart. All this information can then be compared 

with other historical records and current stand 

analyses to indicate how conditions have changed 

in the past century.
What have these investigations revealed? Today’s forests are often very 

different in structure from pre-settlement forests. Forest fires behave much differently 

from the past as a result of changes in forest structure.

Scientific reconstructions show fire to have played a recurring role in shaping 

plant communities in almost every forest and grassland ecosystem in the western United 

States, as well as in the oak-shrublands and pine forests of southern and eastern regions. 

In prairie and savanna ecosystems the natural return interval for fire pre-historically 

may have been as short as 1-4 years. Even in oak woodlands and southern shortleafpine forests, a return interval of 5 years was not uncommon. In many mid-elevation 

ponderosa pine forests, particularly in the Southwest, the natural fire return interval 

ranged from 6-20 years. Only in the moist spruce-fir forests of higher elevations or in the 

dry piñon-juniper woodlands of western foothills (where widely spaced trees and a lack 

of groundcover carried fire poorly) did the average fire interval stretch out to 200 or 400 

years or more.

This does not mean, however, that all oak woodlands burned every 5 years, or that 

a ponderosa pine forest was “overdue” if it had not experienced fire for 20 years. In one 

of the most extensive investigations of its kind, studies in central Colorado’s ponderosa 

belt—in the very place where the uncharacteristically severe Hayman fire burned—

revealed a total of 77 fire years between 1197 and 1963 (the latter being the most recent 

fire year until 2002). Fires ranged in scale from thinning of small stands of trees to 

scorched hillsides across the forest landscape. However, intervals between individual fires 

were highly variable, between 3 and 58 years in one stand to over 100 years in others. 

And though the average fire return interval for the entire 10,000-acre study area was 

only 9 years, intervals for individual areas were about 50 years. Large portions of the 

landscape did not burn for a 128-year period between 1723 and 1851.
What were the ecological effects of recurring fire in these ecosystems? Where 

return intervals were short—such as ponderosa pine forests of the Southwest—ground 

fires of low intensity removed seedlings and saplings, consumed accumulated tree litter, 

and accelerated the return of nutrients to the soil. This was nature’s population control, 

maintaining open, park-like forest stands with a continuous ground cover of grasses, herbs, 

and shrubs beneath the forest canopy. Overstory trees surviving the ground fires were 

fewer and larger, in some old-growth forests numbering 40 trees or less per acre. Where 

return intervals were longer—perhaps one or two fires a century as in ponderosa pine in 

the Hayman fire area in Colorado—“mixed severity” fires spread into the canopy in some 

stands. In other stands, fire burned only fuels on the ground. Mixed severity fire left behind 

a much more complex forest landscape. When this happened, temporary openings were 

created in the forest, some of which would persist for many decades while others were soon 

colonized by nearby seed sources. The record shows that these pulses of tree recruitment 

occurred on average every 50 or 60 years. Thus, the most important result of this prehistorical, mixed-severity fire regime was the creation of a diverse, ever-changing mosaic of 

forest habitats. This fire regime supported maximum biodiversity, ecosystem sustainability, 

and watershed protection over large areas.
The Changing Landscape:

    The Last Two Centuries

Three things happened in the last two centuries to change the natural role of fire: The first, oddly enough, was the loss of human-caused fires. A wealth of 

archaeological evidence, ethnographical studies, and oral histories document use of 

fire by Native Americans in many parts of the country—for resource management, 

pest control, land clearing (sometimes for fire-proofing villages), and even malice 

and warfare. Fire probably escaped to burn far more than intended, though there 

also were areas where Native American burning was uncommon because population 

densities were low. With the spread of Euro-Americans across the continent, the 

fires of indigenous peoples were gradually quelled (though in some areas, especially 

where mining and railroad construction occurred, Euro-American settlers caused 

accidental fires). As the indigenous fires were extinguished, the landscape changed in 

other ways. When Juan de Oñate led his troop of settlers and livestock north out of 

Mexico in 1598, the animals spread faster than range fire, and a different way of life 

was established for the West. By the time the Sacramento National Forest Reserve 

in southern New Mexico was created in 1907, an estimated 17,000 cows and horses, 

10,000 sheep, and 40,000 goats grazed the forest. Free-roaming livestock quickly 

cropped the native grasses in the forest understory, and the lack of fuel reduced the 

frequency and effectiveness of lightning-sparked ground fires. Grazing pressure began 

to diminish in the prolonged droughts of the late 1800s and early 1900s, but it was too 

late for the fire-deprived forests. By then a policy of aggressive fire suppression was in 

place throughout much of the West. Tinkering with the forest ecosystem had started in 

earnest and fire was the first piece of the green machine to be dropped.

Western forests also were seen as a ready source of timber. Mining, railroading, 

and the rapid growth of communities in the West resulted in more than extraction 

of minerals from the earth. Vast areas were subjected to logging. Virgin forests of 

ponderosa pine and other species provided a seemingly unlimited frontier of tall, 

straight trees for lumber. Smaller trees provided railroad ties, mining timbers, and 

fuel. Logging removed many of the old trees, and just as importantly created seedbeds 

for millions of new seedlings to be established. In short order, forests of scattered 

large ponderosa pine trees were replaced by denser forests dominated by young trees.


What were the consequences of these changes in natural fire regime and 

structure of the forests? The conflagrations of 2002—in Colorado, Arizona, and 

Oregon—tell much of the story. As decades of fire exclusion and repeated logging 

allowed successive crops of new seedlings to gain a foothold, the understory began to 

fill in. Gradually the composition and structure of our forests changed. Fire-sensitive 

Douglas-fir often became prominent in ponderosa forests and stand densities reached 

new highs. Rather than having 40 or 50 trees per acre, our mountain slopes were soon 

supporting upwards of 200-400 trees per acre—often 10 or more times the normal 

density. Openings no longer were created by small and isolated stand-replacing fires, and 

those previously existing gradually filled in. The forest canopy, once a diverse mix of 

stands of differing ages, was soon uninterrupted over hundreds of square miles.

This set the stage for fires with very different behavior. As the forest canopy 

closed overhead, young trees reaching for light became fuel ladders, carrying ground 

fires quickly into the crowns of trees. And, once into the crowns, a ground-clearing fire 

is transformed into an all-consuming rage. Witness the record-breaking Hayman fire 

in Colorado: there is no evidence in the scientific record that any fire in pre-historical 

times produced such extensive stand destruction. The diverse patchwork maintained by 

recurring smaller or less severe fires would likely have prevented such from happening. 

These threats were not limited to ponderosa pine forests either. Similar alterations were 

occurring in other ecosystem types across the United States where natural fire was a 

frequent visitor, clearing the way for invasions 

of destructive non-native species better-adapted 

to the new fire regimes and hence able to often 

crowd out natives.


Tough Love: Realigning Our Ideals

With Ecological Reality

Science and history tell us that much of the western landscape we grew up knowing and loving is an artifact of human management from the late 19th century. With fire 

removed from ecosystem processes, and nothing to limit shrub invasions in prairies or 

millions of seedlings in forests, our landscape has become unnatural and unsustainable. 

When fire strikes now, it’s a different problem because the land has been too long 

without. The first step in redressing this situation may be the most difficult--that of 

changing our collective perception of what a healthy and sustainable forest or prairie 

looks like. We have to learn to understand what we see, for we have grown up accepting 

our experience, believing the forests we see today are natural. To deliberately alter 

them seems contrary to the very ethic of good environmental stewardship. But good 

stewardship, and good ecology, often means realizing that many of today’s forests are not 

natural at all. Here the scientific community can help. Carefully done science can provide 

common ground for agreement among different stakeholders, enabling communities to 

unify.

Can we remedy the situation by 

reintroducing fire? Yes, at least partially. 

Can we simply allow natural fires to 

burn again and let nature take over from

there? As a general rule, no. In many cases our 

forests, due to our tinkering, have become too 

vulnerable to runaway crown fires. Even the most 

carefully planned “controlled” burns may constitute 

unacceptable risk to the many people who live in or 

near the forest, at the wildland-urban interface. The 

best science available tells us that at some point we 

must reinstall this missing ecosystem process so the 

natural machinery functions properly again. We have 

to do it cautiously until our forests are restored to a 

more natural condition, and we may need treatments 

other than fire to reduce the risks of reintroducing 
10

fire. In many other places, such as some prairies and shrublands, it is only our perception 

of the role of fire that we must overcome to restore normal ecosystem processes. Fire can 

threaten ranch structures, but lack of fire can be a greater threat to long-term ranching 

livelihood. The larger questions then become: What does restoration involve, on

what scale is it needed, and how will we accomplish it?

Short of rekindling primordial fires, the best way now to reduce the density of our 

forest stands that currently support many more trees per acre than in historical times 

is through mechanical thinning. For many people, however, the prospect of removing 

half or more of the trees from our forests might seem untenable. Objections often come 

down to questions like: What will the new forest look like? Who will profit from 

thinning? Where is thinning ecologically appropriate?

In light of past experience, these are legitimate questions. Most of us treasure the 

forests we grew up with, even if they are ecologically “out of whack.” Suspicion of land 

management agencies as a result of past contracting practices on public lands has not 

always been unjustified. There is some uncertainty as to where logging is warranted. Not 

all forests—for example, high-elevation spruce-fir or lodgepole pine with naturally long 

fire return intervals—have been altered in the same way, so they need different types of 

restorative treatments.

Photo series: Reducing forest density may promote larger and healthier 

trees, fewer disease and insect outbreaks, and greater biodiversity.
11

Still, evidence from recent research 

in the Pacific Northwest, as well as in 

Colorado and the Southwest, indicates 

that less dense forests may promote larger 

and healthier trees, fewer disease and 

insect outbreaks, and greater biodiversity. 

This translates into several social and 

economic advantages: robust game and 

non-game wildlife populations, enhanced 

wildland recreational values, and watershed 

protection. There may be some short-term 

ecological costs; logging on any scale 

temporarily disrupts natural communities, 

shifts competitive balances between species, 

and alters energy flows and nutrient cycles. 

Access roads may increase erosion and 

sedimentation in watersheds, allow greater 

human entry into previously roadless 

areas, and provide conduits for exotic 

species invasions. Nonetheless, carefully 

planned and executed mechanical thinning 

may be the only way back to restoration 

of self-regulating ecosystem processes, 

guaranteeing future generations all the 

physical and spiritual benefits of a diverse 

and healthy forest environment.

And we must recognize this too: 

doing nothing may result in even greater 

long-term ecological costs associated 

with unnaturally large and severe fires. 

Catastrophic fires can set back forest 

recovery many centuries, cause massive 

erosion in watersheds, reduce habitat for 

threatened or endangered species, and 

irreversibly spread non-native species.

Sidebar:  The Jemez Mountains Fire Restoration Project

The Jemez Mountains Fire Restoration Project is situated in northwestern New Mexico 

and encompasses 987,000 acres of mid- to upper-elevation piñon-juniper, ponderosa 

pine, and montane mixed-conifer forest, with fire-adapted grassland and shrub 

communities intermixed. Homes are dispersed widely throughout the area, with 

37,000 acres classed as wildland-urban interface. The project area falls within 10 

different federal, state, and tribal jurisdictions.

Several large, high-intensity fires in recent years (e.g., Cerro Grande) have seriously 

impacted forest ecosystems, archaeological resources, and the economic wellbeing of the region, raising public awareness of the ecological issues involved. With 

assistance from The Nature Conservancy, a team of academic advisors, private 

consultants, and government agency personnel has been assembled to implement a 

new fire management policy to make communities safer and ecosystems healthier. 

The team has identified the following priority tasks:

ÿ Gather and organize baseline ecological and social information.

ÿ Integrate fire risk-reduction with ecological restoration and maintenance.

ÿ Create partnerships that include federal, state, and local agencies and 

organizations and private landowners.

ÿ Build connections between the scientific community and land managers to ensure 

that policy decisions are informed by the best science available.

ÿ Provide a framework for adaptive management - planning, implementation, 

monitoring, and evaluation - within and across administrative and political 

boundaries.

The team has compiled and refined data layers showing fire history and past, current, 

and planned fuel-reduction treatments of the Jemez Mountains. They have also 

constructed models of ecological function for each fire-adapted ecosystem. From 

this information the team has assessed threats to, and measures of the ecological 

integrity of the Jemez landscape.

Now, the goal of the Jemez Mountains Fire Restoration team is to build consensus for 

a coordinated landscape-scale approach to ecological restoration, and then work with 

community leaders on watershed-scale fire management planning.
12

Our Task

Our task will not be easy. The fires of 2002 and others in recent years demonstrated a landscape-scale problem, and isolated small-scale corrective measures are likely to 

be completely overwhelmed in a large burn as they were in the Hayman fire. Thinning 

on a large scale will require commitment and innovation from the private sector. The 

land area, public and private, requiring restoration is now vast. Most trees that must be 

removed from our forests are of small diameter and presently non-merchantable— thus 

requiring imaginative new-product development and financing. Though this may 

sound formidably difficult and expensive, we as a people have never shied away from 

innovation. We have seen repeatedly in recent years that more sustainable management 

of our resources has led to significant economic and social benefits.

The problem facing us today did not occur overnight, and it’s not likely to be 

corrected overnight. Complex problems are rarely solved with little effort. This shouldn’t 

discourage us, however, from taking steps toward a solution, for the road may turn out 

smoother than we think. Good ideas evolve as we gain new ecological insights and 

adjust management activities accordingly. We don’t need all the information available to 

get started, provided that management decisions are continuously re-evaluated with new 

information and experience.

Starting simply can yield incalculable benefits in the long run—and a good start 

might be to expand on Aldo Leopold’s admonition. Save all the pieces—save all

the processes. Ecosystems must have the potential for supporting all naturally 

occurring organisms and their assemblages—the pieces—in the system, along with the 

physical environment needed to support them, regardless of whether their role in the 

system is understood. In addition, ecosystem processes and their frequency, distribution, 

and intensity must be retained or restored to allow ecosystems to self-regulate. These 

processes include natural disturbances such as floods and fire. To this short list we might 

add think long term. Ecosystems function in time scales well beyond the normal 

human experience. Soils develop over millennia and forests require centuries to mature. 

Some management goals will be accomplished only over generations of leadership. But 

small steps make for great strides. What matters most now is getting started and using 

the best science available to guide the process.
13

What can you do?

4Get involved in a community-based conservation group working on 

local landscape restoration projects.

4Educate yourself about the role of fire in your local ecosystems.

4Provide feedback on National Forest, BLM, or other agency land 

management plans.

4Consult with regional experts or The Nature Conservancy on how to 

safely reintroduce fire to your ranch or land holding.

4Participate in local Firewise workshops to learn how to treat fuels 

around your home and create defensible space (www.firewise.org).

Start simply. But start.
Authors:

Merrill R. Kaufmann, U.S.

Department of Agriculture,

Forest Service, Rocky Mountain 

Research Station, Fort Collins, CO

Ayn Shlisky, The Nature 

Conservancy, Boulder, CO

Peter Marchand, Catamount

Center for Geography of the 

Southern Rockies, Woodland

Park, Colorado

The U.S. Department of Agriculture (USDA) prohibits 

discrimination in all its programs and activities on 

the basis of race, color, national origin, sex, religion, 

age, disability, political beliefs, sexual orientation, 

or marital or family status. (Not all prohibited bases 

apply to all programs.) Persons with disabilities who 

require alternative means for communication of 

program information (Braille, large print, audio-tape, 

etc.) should contact USDA’s TARGET Center at (202) 

720-2600 (voice and TDD).

To file a complaint of discrimination, write USDA, 

Director, Office of Civil Rights, Room 326 W, Whitten 

Building, 1400 Independence Avenue, SW, Washington, 

D.C. 20250-9410 or call (202) 720-5964 (voice and TDD). 

USDA is an equal opportunity provider and employer.

This publication was in-part supported by The Nature 

Conservancy and by the Restoration of Fire-adapted 

Ecosystems cooperative agreement (#04-CA-11132543-

037) between The Nature Conservancy, the USDA Forest 

Service, and the Department of the Interior.