Historical and Current Fire Management 

Practices in Two Wilderness Areas in the 

Southwestern United States: The Saguaro 

Wilderness Area and the Gila-Aldo Leopold 

Wilderness Complex

Molly E. Hunter, Jose M. Iniguez, and Calvin A. Farris

United States Department of Agriculture

Forest Rocky Mountain General Technical Report

Service Research Station RMRS-GTR-325 August 2014
Hunter, Molly E.; Iniguez, Jose M.; Farris, Calvin A. 2014. Historical 

and current fire management practices in two wilderness areas in 

the southwestern United States: The Saguaro Wilderness Area and 

the Gila-Aldo Leopold Wilderness Complex. Gen. Tech. Rep. RMRSGTR-325. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, 

Rocky Mountain Research Station. 38 p.

Abstract

Fire suppression has been the dominant fire management strategy in 

the West over the last century. However, managers of the Gila and Aldo 

Leopold Wilderness Complex in New Mexico and the Saguaro Wilderness 

Area in Arizona have allowed fire to play a more natural role for decades. 

This report summarizes the effects of these fire management practices on 

key resources, and documents common challenges in implementing these 

practices and lessons for how to address them. By updating historical fire 

atlases, we show how fire patterns have changed with adoption of new 

policy and practices.

Keywords: prescribed fire, managed wildfire, Southwest

Authors

Molly E. Hunter, School of Forestry, Northern Arizona University, Flagstaff, 

Arizona.

Jose M. Iniguez, USDA Forest Service, Rocky Mountain Research 

Station, Flagstaff, Arizona.

Calvin A. Farris, National Park Service, Klamath Falls, Oregon.

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Contents

INTRODUCTION................................................................................................. 1

Background, Purpose and Scope................................................................................................1

Terminology .................................................................................................................................2

METHODS........................................................................................................... 2

STUDY AREAS................................................................................................... 3

Geography...................................................................................................................................3

Vegetation Communities..............................................................................................................5

Cultural History ............................................................................................................................8

HISTORY OF FIRE REGIMES AND MANAGEMENT ........................................ 9

Pre-Euro-American Settlement Era (Prior to 1900).....................................................................9

Fire Exclusion Era (1900-1970)................................................................................................. 11

Managed Fire Era (1970 – 2010)...............................................................................................12

Megafire Era (2011 – present)...................................................................................................17

EFFECTS OF MANGED WILDFIRE AND PRESCRIBED FIRE ...................... 20

Fuels, Forest Structure, and Potential Fire Behavior.................................................................20

Threatened, Endangered, and Sensitive Species .....................................................................23

Aquatic Habitat and Species......................................................................................................23

Mexican Spotted Owl.................................................................................................................23

Wildlife Habitat and Populations................................................................................................24

CURRENT CHALLENGES TO IMPLEMENTING MANAGED WILDFIRE....... 25

Threatened and Endangered Species.......................................................................................25

Public Support for Fire Programs ..............................................................................................25

Risk of Escape...........................................................................................................................26

Invasive Species........................................................................................................................26

Reintroducing Fire in Mixed to High Severity Fire Regimes ......................................................27

LESSONS LEARNED....................................................................................... 28

Managed Wildfire and Prescribed Fire Can Restore Southwestern Forests .............................28

Managed Wildfire, Large-Scale Prescribed Fire, and Suppression Fires Create 

Landscape Fire Mosaics That Provide Opportunities for Fire Managers..............................29

Collaboration Across Disciplines and Agencies Is Imperative ...................................................29

Preparation and Public Outreach Is Critical...............................................................................30

CONCLUSION .................................................................................................. 31

ACKNOWLEDGMENTS ................................................................................... 31

REFERENCES.................................................................................................. 31

GLOSSARY....................................................................................................... 35

APPENDIX A: MANAGERS INTERVIEWED.................................................... 36

APPENDIX B: RESEARCH NEEDS................................................................. 37

USDA Forest Service RMRS-GTR-325. 2014. 1

INTRODUCTION

Background, Purpose and Scope

Suppressing wildfires has been the dominant fire 

management strategy over most of the western United 

States for the last century. In forested systems adapted 

to frequent fire, this practice, in part, has resulted in 

contemporary forests with declining ecological conditions, large build-up of fuels, and increased potential 

for large, high-intensity and stand replacing wildfire 

(Covington and others 1994). However, in some areas 

managers have been able to adopt more flexible policies over the last few decades to allow fire to play a 

more natural role. Two of the most notable examples 

occur in the southwestern United States: the Gila and 

Aldo Leopold Wilderness Complex (GALWC) in the 

Gila National Forest (GNF) in New Mexico, and the 

Saguaro Wilderness Area (SWA) in Saguaro National 

Park (SNP) in Arizona (figure 1). Over the last 30 to 40 

years, policies that facilitated the management of lightning and prescribed fires in these areas have resulted in 

the large-scale reintroduction of frequent fire as an ecological process. As a result, current forest conditions 

are strikingly different compared to long-unburned forests that can be found throughout the rest of Southwest.

Forest managers across the Southwest have long 

recognized the need to restore historical forest structure and reduce fuels following a century or more of 

fire exclusion. Mechanical treatments are often used to 

accomplish this goal in non-wilderness areas, but managers are increasingly relying on fire as a restoration 

tool for three main reasons: (1) the lack of a timber industry and local wood products manufacturing plants 

that can make mechanical treatments economically viable, (2) recent fire policy guidelines that now allow 

more flexibility in the use of fire, and (3) the need to 

work at landscape scales to effectively reduce the threat 

of large, high-intensity fires. Fire is often more efficient 

to implement than mechanical methods across large 

scales; the cost per acre of fire is typically lower and 

it is less restricted by access, topography, or legal challenges (Hunter and others 2007). Similar circumstances 

initially propelled the use of large-scale fires in wilderness areas within the GALWC and SWA. After several 

decades of fire management these two areas offer a 

wealth of knowledge that could aid managers who are 

now beginning to rely more on fire as a restoration tool 

in other forests throughout the western United States.

The purpose of this report is to document and synthesize the current and historical fire management 

practices in the GALWC and SWA, the effects of reintroduced fires on critical natural resources, and provide 

examples of how managers have addressed common 

challenges in implementing these fire programs. We 

culminate our findings with a discussion of key “lessons learned” from these unique programs. These 

lessons are broad concepts that are supported by the 

literature and conversations with managers and are applicable across both study areas. They represent what 

we have learned from these fire management programs 

that could be applicable to other areas where the practice of using fire as a restoration tool at landscape 

scales is in its infancy.

Figure 1—Location of the Saguaro 

Wilderness Area in Saguaro National 

Park (Arizona) and the Gila Aldo Leopold 

Wilderness Complex in the Gila National 

Forest (New Mexico).
2 USDA Forest Service RMRS-GTR-325. 2014.

Terminology

Terminology regarding the management of naturally 

ignited fire for restoration has changed numerous times 

since the practice was first adopted as official policy. 

When the policy was first implemented by a handful 

of National Park units in the late 1960s it was called a 

variety of things: “let burn,” “natural prescribed fire,” 

or “natural fire management” (van Wagtendonk, 2007). 

Over time, as policies were revised, the term “prescribed natural fire” took hold. A review and update 

of national fire policy in 1995 further reaffirmed the 

practice and introduced the term “wildland fire use for 

resource benefit,” referred to as “wildland fire use” or 

often “fire use” (Philpot and others 1995).

The latest change in terminology came with the release of the 2009 Federal Interagency Implementation 

Guide (Fire Executive Council 2009). In the past, official policy distinguished three types of fire: wildland 

fire use, prescribed fire (intentionally ignited by managers), and wildfire (unwanted and suppressed fire). 

The most current guidelines recognized just two types 

of fire: wildfire and prescribed fire. This is an important 

distinction because under the former policy a fire resulting from a natural ignition had to be declared either 

a wildfire or “wildland fire use” and either suppressed 

or managed for resource objectives (but not both). With 

the new policy interpretation, a single wildfire can be 

managed for multiple objectives, allowing mangers to 

aggressively suppress areas of a fire where resources 

are threatened and apply minimal suppression strategies in areas where a fire is benefiting and/or posing 

minimal threat to key resources. A common terminology describing this practice has yet to be widely adopted 

and can include multiple labels, including, “minimal 

suppression,” “contain,” “confine,” and “multiple objective fire.”

For simplicity, throughout this report we use the 

term “managed wildfire” to describe all naturally 

ignited fires in GWALC and SWA that have been managed with a strategy other than full suppression. This 

would encompass any fires that in the past might have 

been labeled “prescribed natural fire,” “wildland fire 

use,” “multiple objective fire,” or other related terms. 

Regardless of the specific terminologies used over 

time, these natural ignitions were managed with relatively similar overall strategies and objectives, and can 

be lumped into a single category. The term “prescribed 

fire” is used to describe any fire intentionally set by 

managers to meet specific resource objectives and 

“suppression fire” to describe any unwanted fire that 

was actively suppressed.

It should be noted that there is obviously overlap 

between managed, prescribed, and suppression fires. 

For example, a full suppression fire may involve indirect tactics such as utilizing natural barriers for 

safety. Conversely, managed wildfires often involve 

some level of direct suppression strategies such as line 

construction and firing operations to limit spread into 

undesirable areas or to manipulate fire intensity and 

effects (particularly in recent years due to more flexible policies). Moreover, some fires in the past started 

under one classification but were converted to another. 

For example, the 1994 lightning-ignited Rincon Fire 

in SWA was initially a “managed wildfire” (prescribed 

natural fire at that time) but was subsequently converted to full suppression fire when it burned outside of a 

specified area and acceptable fire behavior/weather parameters. Despite these ambiguities, this classification 

serves as a useful means of clarifying confusing terminology and examining how the use of fire has changed 

over time in the study areas.

METHODS

We used a combination of approaches to document 

and synthesize the historical role of fire and the effects 

of contemporary fire programs on critical resources in 

the GWALC and SWA. First, we conducted an extensive literature review of both peer-reviewed studies and 

grey literature regarding fire ecology and fire management practices in both study areas. Secondly, to identify 

challenges and keys to success in implementing the fire 

programs, we interviewed several managers (both current and retired) from a variety of disciplines in each 

study area. This included phone interviews, email discussions, and informal conversations on field trips and 

in other settings. Those interviewed represent over 200 

years of cumulative fire management experience in 

these study areas; they provided invaluable insight into 

the challenges and processes of implementing innovative fire management strategies (see list of names in 

Appendix A). Results from that effort are documented 

throughout this report.

Third, to document the landscape scale patterns of 

fire occurrence over time resulting from changing management strategies, we updated previously published 

fire history atlases (Farris and others 2010; Rollins and 

others 2001) using data obtained from the National Park 

Service, The U.S. Forest Service, and the Monitoring 

Trends in Burn Severity database (www.mtbs.gov, last 

accessed 6/7/2013). Fire frequency maps encompassed 

the period from 1909 to 2013 at GALWC, and 1937 to 

2013 at SWA, and included adjacent areas. Prescribed 
USDA Forest Service RMRS-GTR-325. 2014. 3

fires were not listed in the original fire history atlas 

for the GNF. However, using the Monitoring Trends 

in Burn Severity database (http://www.mtbs.gov/), we 

were able to update it to include prescribed fires over 

1,000 acres in size that occurred after 1984. We also 

calculated cumulative area burned and proportion of 

area burned by each fire type (managed, prescribed, 

suppression) over time. In the SWA, this analysis was 

restricted to the greater Mica Mountain Study Area 

(MMSA). This area supports the primary coniferous 

forest belt in the wilderness, which has been the main 

focus of most managed and prescribed fires.

We conclude the report with some key “lessons 

learned” from the fire management programs in the 

GAWLC and SWA. These were the culmination of 

the work that went into producing this report (literature review, interviews with managers, and fire history 

analysis). The list of lessons learned is certainly not 

comprehensive, but it represents a set of recurring, core 

ideas that were conveyed independently by various 

managers across both of the study areas, and had strong 

support in the literature and in our own analyses. We 

chose lessons with multiple lines of corroboration, assuming that they would be more likely to be applicable 

across broad geographic areas, including non-wilderness, and potentially most useful where using fire as a 

large-scale restoration tool is at an earlier stage of development. We also present these lessons as a starting 

point in hopes that managers in other areas will add to 

them based on their own experience.

STUDY AREAS

Geography

The GALWC in central New Mexico encompasses 

558,014 acres and is composed of two main mountain 

ranges (figure 2). The Mogollon Mountains dominate 

the western half of the study area. They rise to an elevation of 10,742 feet and fall abruptly toward the west 

and south and more gently toward east and north. The 

Black Range is a smaller range that runs south to north 

along the eastern part of the GALWC. These two main 

mountain ranges are the headwaters for the Gila River. 

Between them the land is dominated by steep canyons and large expansive mesas. The entire landscape 

was formed by volcanic activity in the Cretaceous Era 

(USGS 1965).

The SWA in southern Arizona is 70,905 acres and 

encompasses most of the Rincon Mountains, which are 

part of the Basin and Range Province that dominates 

the landscape across southern Arizona and the northern 

state of Sonora in Mexico. These mountain ranges were 

uplifted during the mid-Tertiary Era (Baisan 1990). The 

main mass of the Rincon Mountains is composed of 

granite gneiss although limestone outcrops can also be 

found throughout. The Rincon Mountains rise abruptly 

from the Sonoran Desert to an elevation of 8,432 feet 

above sea level. The two main physical features of the 

Rincon Mountains are two peaks, Mica Mountain and 

Rincon Peak to the south (figure 3). Mica Mountain 

Figure 2—Detailed map of the Gila 

Aldo Leopold Wilderness Complex and 

surrounding lands in the Gila National 

Forest. The main physical features of 

the Gila Wilderness are the Mogollon 

Mountains in the northwest along with 

the three forks of the upper Gila River. 

The main physical feature of the Aldo 

Leopold Wilderness is the north-south 

running Black Range.
4 USDA Forest Service RMRS-GTR-325. 2014.

slopes gently along the top but drops off abruptly on 

three sides towards the desert. Rincon Peak is steeper 

and dissected. The two high points are connected by 

Happy Valley saddle, which supports a stand of ponderosa pine at 6,234 feet elevation (figure 4).

Both study areas have a seasonally bimodal precipitation pattern. In the winter (November to March), frontal 

storms bring snow to higher elevations and rain to the 

lower elevations. In the mid- to late-summer (July to 

August), moisture from Mexico creates a “monsoonal” 

weather pattern with thunderstorms. The arid “foresummer” period (April to June) preceding the “monsoonal” 

moisture is typically very hot and dry and is when most 

large fires burn. Annual precipitation varies greatly by 

elevation. In the GAWLC, averages range between 12 to 

28 inches from roughly 4,500 to 11,000 feet in elevation. 

In the SWA, average annual precipitation ranges from 

about 13 inches at the base of Mica Mountain (~2,500 

feet) to 27 inches at the summit (8,666 feet).

Both study areas represent very remote and inaccessible areas, making them ideal places to experiment 

with managed wildfire. While there are some towns 

on the outskirts of the GALWC and GNF (Silver City, 

New Mexico, and Reserve, New Mexico) and private 

inholdings throughout, the human population density 

in the region is relatively low. Although SWA and SNP 

is located next to a major metropolitan area (Tucson, 

Arizona), its rugged, roadless terrain, difficult access, 

and surrounding unburnable fuels (desert) resulted in 

functional isolation for fire management purposes (figure 5). While there are some historical structures and 

significant cultural sites in both study areas, there are 

Figure 3—Detailed map of the 

Saguaro Wilderness Area in Saguaro 

National Park and the adjacent 

Rincon Mountain Wilderness Area in 

the Coronado National Forest. The 

outlined Mica Mountain Study Area 

represents a 6,870 acre area on 

Mica Mountain where the prescribed 

fire and managed wildfire program 

has been focused. It is also where 

most fire history studies have been 

conducted.

Figure 4—View from 

the top of Rincon Peak 

looking north across 

Happy Valley Saddle to 

Mica Mountain in the 

background (photograph 

by Michael Crimmins, 

University of Arizona).
USDA Forest Service RMRS-GTR-325. 2014. 5

very few modern human developments directly adjacent 

to the wilderness areas.

Vegetation Communities

Both study areas are located at the junction of two 

major biomes. From the north there is a Rocky Mountain 

Cordillera influence and from the south there is a 

Madrean influence. The sharp vertical relief and unique 

geographic position of these mountains combine to create a diverse mosaic of vegetation assemblages stratified 

along elevation/moisture gradients (Niering and Lowe 

1984). Plant communities at higher elevations (above 

6,000 feet) are closely related to the Cordilleran/Rocky 

Mountain floristic province. Plant communities in lower 

elevations (below 6,000 feet) are primarily influenced 

by the Madrean floristic province (McLaughlin 1995). 

For the sake of simplicity, however, we have identified 

three broad vegetation communities that this report will 

focus on: pinyon-juniper woodlands, ponderosa pine 

forests, and mixed-conifer forests (figure 6).

Pinyon-juniper woodlands typically occur in areas below 6,500 feet elevation although they can also 

be found at higher elevations on drier south-facing aspects (figure 7). The dominant tree species within the 

pinyon-juniper plant community include alligator juniper (Juniperus deppeana Steud.), Rocky Mountain 

juniper (Juniperus scopulorum Sarg.), one-seed juniper 

(Juniperus monosperma (Engelm.)Sarg.), pinyon pine 

(Pinus edulis Engelm.) and border pinyon (P. discolor

D.K. Bailey and Hawksw). Three general pinyon-juniper vegetation types have been identified across the 

western United States: persistent pinyon-juniper woodlands, pinyon-juniper savannas, and wooded shrublands 

(Romme and others 2009). The persistent woodland and 

wooded shrubland types are generally characterized as 

having higher tree and shrub density and lower grass 

cover in the understory compared to the savanna type. 

Both the persistent woodland and savanna types occur 

in the GNF, although the savanna type was historically 

much less prevalent (Miller 1999). Various pinyon and 

juniper species can be found at lower elevations in the 

pine/oak woodlands in SWA, which also includes a 

number of Madrean oak species.

Ponderosa pine forests are generally found at midelevations between 6,500 and 8,500 feet elevation 

(figure 8). The dominant tree species in these forests 

are ponderosa pine (Pinus ponderosa C. Lawson) and 

sometimes Gambel oak (Quercus gambelii Nutt.). In 

SWA, pine forests also includes Madrean species such 

as Apache pine (Pinus engelmanii Carr.), Chihuahua 

pine (P. leiophylla Schiede & Deppe), Arizona pine 

(Pinus arizonica), silverleaf oak (Quercus hypoleucoides A. Camus), Arizona white oak (Q. arizonica Sarg.), 

and Emery oak (Q. emoryi Torr.) (figure 9).

Mixed conifer forests are generally found between 

8,500 and 10,000 feet elevation (figure 10). Common 

tree species within mixed conifer forests include 

Douglas-fir (Pseudotsuga menziesii [Mirb.] Fanco), 

white fir (Abies concolor [Gord. & Glend.] Hildebr.), 

southwestern white pine (Pinus strobiformis Engelm.) 

quaking aspen (populus tremuloides Michx.) and ponderosa pine. Forest structure and composition generally 

changes dramatically along an elevation-temperaturemoisture gradient between warmer, drier ponderosa pine 

and colder, wetter spruce-fir forest types. Mixed-conifer 

can be further separated into warm/dry and cool/moist 

subtypes that occupy each end, respectively, of the elevation-temperature-moisture gradient (Evans and others 

2011) (figure 11). The cool/moist type occurs at the 

highest elevations but can also be found on north-facing 

aspects at lower elevations (figure 11a). The main distinguishing feature of this type is that although ponderosa 

pines maybe present they are not usually dominant. The 

warm/dry type occurs at the lower elevations or on 

south-facing slopes at higher elevations. This type can 

Figure 5—View of 

ponderosa pine and 

mixed conifer forests in 

the Mica Mountain Study 

Area (Helens Dome in 

foreground), looking west 

across desert vegetation and 

the city of Tucson Arizona in 

the background (photograph 

by Calvin Farris, National 

Park Service).
6 USDA Forest Service RMRS-GTR-325. 2014.

Figure 6—Maps of vegetation communities in (a) the Gila and Aldo Leopold Wilderness Complex and 

surrounding lands, and (b) Saguaro National Park. Vegetation categories are derived from Landfire Data 

(www.landfire.gov; last accessed 1/21/14).
USDA Forest Service RMRS-GTR-325. 2014. 7

Figure 7—Typical unburned pinyon-juniper vegetation in 

the Gila National Forest. This vegetation community tends 

to occur at lower elevation within these mountain ranges 

(photograph by Molly Hunter, Northern Arizona University).

Figure 8—Southwest ponderosa pine forest in the Gila 

National Forest. Although ponderosa pine can be found with 

other species at its lower and higher elevation limits, it often 

forms large stands or pure ponderosa pine. Historically, 

such stands were open and dominated by large trees due to 

frequent fires; however, due to logging and fire suppression, 

stands such as this one in the Gila wilderness are relatively 

rare in the Southwest (photograph by Jose Iniguez, USDA 

Forest Service).

Figure 9—Ponderosa pine forests in Saguaro National 

Park often include a number of Madrean oak species in the 

understory. Rincon Peak is in the background (photograph 

by Calvin Farris, National Park Service).

Figure 10—Mixed conifer forests are limited to a few 

isolated locations on north aspects in Saguaro National 

Park, but occur extensively across higher elevations in the 

GALWC. This scene is in the Mogollon Mountains taken 

prior to the 2012 Whitewater-Baldy fire that burned much 

of the landscape (photograph courtesy of USDA Forest 

Service).
8 USDA Forest Service RMRS-GTR-325. 2014.

contain the same mix of associated species as the cool/

moist type but ponderosa pine is often still dominant or 

co-dominant (figure 11b).

Cultural History

The two study areas share many cultural history 

similarities. Prior to European settlement both areas 

were home to various Native American groups. The 

earliest known inhabitants in the greater GNF landscapes were the Mogollon culture. They were followed 

by the Pueblo Indian Cliff Dwellers who occupied the 

area in the 13th and 14th centuries and, like other native 

cultures, abruptly abandoned the areas for unknown 

reasons (Cordell 1997). In SNP the oldest known inhabitants to the general area were the Hohokam who, 

as farmers, mainly occupied the desert valley bottoms 

near reliable water sources. By the 13th century, the 

Apaches began migrating to the Southwest from northern regions. Unlike prior inhabitants of the Southwest, 

the Apaches primarily hunted and gathered and thus 

utilized both valley bottoms as well as upland forested 

areas.

Spanish settlers began moving into the Southwest 

in the 16th and 17th centuries (Clemensen 1987). Early 

Spanish explorers were mainly interested in finding 

gold and silver. By the 1600s, settlements developed 

around mining camps near what is now the GNF and 

around missions near the Rincon Mountains. These 

activities had a great impact on the land in the form 

of timber harvesting, which was needed both for construction and fuel. However, significant impacts were 

mostly confined to areas in close proximity to settlements. Moreover, through the 1800s the presence of 

Figure 11—Mixed conifer in the two study 

areas can be divided into (a) cool/moist and (b) 

warm/dry types. The cool/moist mixed conifer 

forests are distinguished by a general absence 

of ponderosa pine. The closed canopy and 

abundant coarse woody debris in the cool/moist 

mixed conifer forest make it ideal habitat for 

Mexican Spotted Owls (photographs by Calvin 

Farris, National Park Service).
USDA Forest Service RMRS-GTR-325. 2014. 9

Apache groups restricted Euro-American settlement in 

and around high elevation forests (Bigelow 1968). By 

1856 both the Gila and the Rincon Mountains became 

part of the United States territory. Around the same 

time, the area saw the arrival of the railroad in 1880 

and the capture of the last Apaches (Bigelow 1968). 

These two events allowed greater Euro-American 

settlement and brought about significant ecological changes throughout southwestern forests (Cooper 

1961; Weaver 1951).

By the close of the 19th century, both areas had been 

declared part of the National Forest Reserve system and 

off limits to new settlement. By 1906 they became part 

of the newly created National Forest system. In 1924, 

due to the efforts of many including Aldo Leopold, 

the Gila Wilderness was set aside and became the first 

wilderness areas in the world (Roth 1990). In 1933 

the Rincon Mountains were taken out of the National 

Forest system and designated a National Monument 

(Clemensen 1987). By 1976 the Saguaro Wilderness 

Area and the Gila Wilderness Area were officially designated with the passage of the Wilderness Act. The 

Aldo Leopold Wilderness Area was designated in 

1980; in 1994 Saguaro was named the 52nd National 

Park.

HISTORY OF FIRE REGIMES AND 

MANAGEMENT

With an abundance of ignition sources, receptive 

fuels, and frequent intra- and inter-annual drought, 

forested landscapes in the Southwest are some of 

the most fire-prone in the United States. These two 

study areas are no exception, yet fire occurrence has 

fluctuated a great deal over the past 120 years due to 

human influences. Thus, we divided the discussion 

of fire history in our study areas according to major 

human-caused changes in the fire regime. The PreEuro-American Settlement Era includes years prior 

to 1900, which is approximately when the arrival of 

Euro-Americans dramatically changed the role of fire 

in these landscapes. The Fire Exclusion Era encompasses the period of about 1900 to 1970 when fire was 

virtually eliminated from the landscape due to fire suppression and land use changes (heavy grazing, logging, 

etc.). The Fire Management Era begins around 1970 

and continues into the beginning of the 21st century. 

This represents the time when fires were reintroduced 

through prescribed fire and managed wildfire. We end 

the discussion with the present day as we enter the 

Megafire Era in the Southwest. This time period is 

characterized by the increasing incidence of large and 

intense wildfires concurrent with rising global temperatures and intensifying drought conditions (Stephens 

and others 2014; Westerling and others 2006).

Pre-Euro-American Settlement Era 

(Prior to 1900)

Prior to Euro-American settlement, the fire regime 

in each of these landscapes varied by vegetation type, 

reflecting the significant differences in rates of fuel 

accumulation and fire-season length. Within the pinyon-juniper woodlands, live and dead fuels accumulate 

relatively slowly due to limited moisture and high temperatures. Fire history studies in these woodlands in 

both SWA and the GALWC are lacking, but inferences 

can be made from studies in pinyon-juniper woodlands 

throughout the Southwest. Although the fire season is 

relatively long and ignitions are plentiful, widespread 

fires were likely infrequent historically. That is, the 

mean fire interval (MFI), or the average number of 

years between fires, was likely greater than 100 years 

due to slow rates of plant growth and the discontinuous nature of fuels (Romme and others 2009). When 

fires did occur, most were likely either very small (impacting one or a few trees) and with variable intensity, 

or large (several hundred acres) high-intensity crown 

fires. More frequent, low intensity fires likely occurred 

in some juniper savannahs or woodlands that supported a dense and continuous grass fuel bed on the order 

of every 20 to 30 years (Margolis 2014).

Mid elevation pine forests have relatively high rates 

of fuels accumulation and a long fire season. Thus, 

they historically supported a fire regime dominated 

by frequent, low-severity surface fires prior to the 20th

century. In the MMSA in SWA for example, Farris 

and others (2013) found that the Natural Fire Rotation 

(NFR), or the time required on average to burn an area 

equivalent to size the entire study area, during the 19th

century was only 10 years. Between 1630 and 1900, a 

large fire (at least 25 percent of the study area) burned 

somewhere within MMSA every 7 to 8 years, on average (Baisan and Swetnam 1990; Farris and others 

2013). The MFI within small stands or groups of stands 

ranged from 6 to 13 years in the GALWC prior to EuroAmerican settlement (Swetnam and Baisan 1996) 

(table 1). Fires of this frequency would have mainly 

consumed surface fuels and had relatively minimal impacts on the overstory. Most fires in both study areas 

occurred during the hot, dry arid foresummer between 

May and early July, prior to the onset of “monsoonal” 

moisture moving into the region (Abolt 1997; Baisan 

and Swetnam 1990).
10 USDA Forest Service RMRS-GTR-325. 2014.

Fuels also accumulate at relatively rapid rates in the 

mixed conifer forests, but the length of the fire season 

is shorter compared to ponderosa pine forests because 

snow can remain on the ground into the early summer months. Historical fire regimes in mixed conifer 

forests were highly variable ranging from relatively 

frequent low-severity surface fires in transition areas 

between pine and mixed conifer forests to infrequent 

high severity fires at higher elevations where mixed 

conifer forests transitions to spruce-fir. The extent of 

mixed conifer forests in the SWA is limited, covering 

less than 400 acres. These stands are generally found 

adjacent to pine forest but in cooler north-facing slopes 

and ravines and historically experienced surface fires 

of variable intensity at 15- to 30-year intervals (Baisan 

1990; Iniguez and others 2009). In the GALWC, similar dry mixed conifer forests experienced a fire every 

13 years on average (table 1), although individual 

intervals ranged between 3 and 30 years at the stand 

level (Abolt 1997; Baisan and Swetnam 1990).

Although absent in the SWA, the GAWLC, also contains the wet/cool mixed conifer type on north-facing 

aspects that transition into spruce-fir forests. Winter 

snowpack tends to persist well into the summer in these 

forests and they are also the first to receive the summer 

rains, resulting in a relatively short fire season. As a 

result, these forests tended to experience relatively infrequent (every 30 to 400 years), mostly high severity 

fires (Abolt 1997; Margolis and others 2011). Although 

fires likely ignited somewhere on these landscapes on 

an annual basis, in most years fuels would have been 

too wet to support fire spread and fires would burn 

only a few acres. During very dry years, however, the 

wetter mixed conifer sites would support large standreplacing fires of 500 to 1,200 acres in size (Margolis 

and others 2011).

Table 1: Summary of published pre-20th century Mean Fire Return Intervals (MFI) in the Gila wilderness and Mica 

Mountain study areas (MMSA). Vegetation type sampled includes ponderosa pine (PIPO), mixed conifer (MC), and 

spruce-fir (SF). For blank values, the statistic either was not reported or not applicable because of stand size.

Vegetation

Elevation 

(feet)

Fire-scar 

samples

Area 

(acres) MFIall MFI10% MFI25% Time period

——Gila Wilderness——

PIPO/MCa 8,400-9,290 27 ~740 3.0 5.8 13.1 1700-1900

PIPOa 8,300 10 ~110 4.5 8.3 8.7 1700-1900

PIPOa 7,600-7,800 12 ~860 3.5 6.3 6.9 1700-1900

PPb 7,810 18 590 5.1 5.5 8.4 1700-1900

MC/PIPO 8,640 1 n/a 10.8 — — 1700-1900

MCb 10,100 9 50 12 — — 1700-1900

MC/PIPOb 8,690 16 60 7 — — 1700-1900

MCb 8,860 4 32 15 — — 1700-1900

SF/MCb 9,510 4 7 42 — — 1700-1900

MCb 9,020 6 10 8 — — 1700-1900

——Mica Mountain——

PIPOc 8,304 4 3d 7.3e — — 1631-1900

PIPOc 8,055 7 6d 6.7e — — 1631-1900

PIPOc 8,219 4 3d 6.9e — — 1631-1900

MCc 8,241 4 6d 9.9e — — 1631-1900

PIPO/MCa 7,005-8,488 12 sites 6,870g — 6.1 7.3 1631-1900

PIPO/MCf 7,005-8,488 60 sites 6,870g — 6.2 8.0 1800-1900

a From Swetnam and Baisan 1996.

b From Abolt 1997.

c From Baisan and Swetnam 1990.

d Approximate size of area individual trees were sampled from; estimated from maps in Baisan 1990.

e Only includes intervals between fires that scarred more than one tree at a collection site.

f From Farris et al. 2013.

g Size of the entire MMSA study area. 
USDA Forest Service RMRS-GTR-325. 2014. 11

Widespread fires across ponderosa pine and mixed 

conifer forests tended to be synchronized with interannual climate cycles that controlled broad-scale 

patterns of fuel production and drying (Swetnam and 

Baisan 1996). In the GALWC for example, Swetnam 

and Baisan (2003) identified at least 26 widespread 

fire years between 1605 and 1904 across a gradient of 

elevation and vegetation ranging from ponderosa pine 

to spruce-fir. Not surprisingly, most years with widespread fires were drier than average and most years 

with small fires were wetter than average. A closer examination of fire-climate relations reveals important 

lagging relationships during the years preceding fires: 

most of the largest fire years occurred during a drought 

year that was preceded by 1 to 3 years of significantly 

wetter/cooler conditions. These wet periods resulted in 

an abundance of fine fuels (especially grasses) across 

the landscape and set the stage for extensive fires when 

the next dry year occurred. Small fire years were preceded by relatively dry years that inhibited build-up of 

grasses and needles. These lagging relationships were 

weaker or absent in cool/wet mixed conifer forests 

dominated by woody fuels where drying was the most 

important factor (Swetnam and Baisan 1996, 2003).

Fire Exclusion Era (1900-1970)

The cultural changes brought about by the arrival of Euro-Americans at the end of the 19th century 

significantly altered the natural fire regime and ecology 

of these landscapes. After 1910, total annual area burned 

decreased dramatically in both the SWA and GALWC. 

For example, despite high rates of 20th century burning 

compared to other pine-dominated forests in the West, 

the NFR in the MMSA increased from 10 years in the 

19th century to 31 years for the period 1937 to 2013 

(Farris 2009; updated using data described in the methods section). A similar pattern occurred in GALWC 

fire history datasets (Swetnam and Baisan 1996). This 

was probably due to a number of factors but mainly 

the influx of intensive livestock grazing with the arrival of the railroad. Another contributing factor was that 

these areas were now under management of the U.S. 

Forest Service and active fire suppression was encouraged. The great numbers of livestock that moved into 

the Southwest with the establishment of the railroad 

significantly decreased grass cover and subsequently 

limited the capacity of the landscape to sustain frequent, low intensity fires (Cooper 1961; Weaver 1951). 

Furthermore, organized fire suppression began around 

1910, and became increasingly effective with the use 

of mechanized equipment and aircraft in the 1940s and 

1950s (Pyne 1997).

During this Era, however, fire exclusion was certainly not ubiquitous across these landscapes; their 

relative remoteness and rugged terrain sometimes limited effective fire suppression. In particular, starting 

in the late 1940s and 1950s both areas saw the return 

Figure 12—Decadal fire 

perimeters for the Gila and Aldo 

Leopold Wilderness Complex and 

vicinity. Fire perimeters include 

managed and suppression fires 

for the entire period in addition to 

prescribed fires adjacent to the 

wilderness areas after 1984. Only 

fires that intersected wilderness 

lands are shown. 

2000-2009 2010-2013

1970-1979 1980-1989 1990-1999

1940-1949 1950-1959 1960-1969

1909-1919 1920-1929 1930-1939
12 USDA Forest Service RMRS-GTR-325. 2014.

of some relatively large fires (figures 12 and 13). In 

the SWA, the first major fire in 1943 burned approximately 4,500 acres and by 1959 almost 8,000 acres had 

burned in total. What is particularly notable is that the 

major fires on Mica Mountain during this Era overlapped spatially, resulting in numerous reburns within 

a relatively short amount of time (figures 13). In the 

GALWC, several large fires occurred in the 1950s, including the McKnight Fire in 1951, which burned over 

48,000 acres in the southern end of the Black Range. 

Although these were large fires compared to earlier decades in the Era, they were not as large as the frequent 

fires that burned across these landscapes prior to 1900. 

Still, between 1909 and 1969, a total of 134,000 acres 

burned in the GALWC; by 1970, approximately 25 

percent of the wilderness area had experienced at least 

one fire since 1900 (figure 14). These mid-century fires 

reduced accumulated fuels and reduced tree densities, 

thereby making it more feasible to initiate managed 

wildfire programs in the 1970s (figure 15). 

Managed Fire Era (1970 – 2010)

The managed wildfire program in SWA began in 1971 

following the development of a fire management plan 

approving the practice. It was the second national park 

in the country to adopt such a policy. Managed wildfire 

was first officially implemented in the Gila Wilderness 

in 1975 (Boucher and Moody 1998). The initial fire 

management plans, which were relatively conservative and simple by today’s standards, described several 

Figure 14—Cumulative proportion of area burned at least 

once and at least twice over time in the Gila Aldo Leopold 

Wilderness Complex (GALWC) and Mica Mountain Study 

Area (MICA MTN). Data include all fire types.

Figure 13—Decadal fire perimeters 

in the Mica Mountain study area 

and vicinity. Fire perimeters include 

managed wildfire, suppression 

wildfire, and prescribed fires. Only 

fires that intersected wilderness 

lands are shown.

2000-2009 2010-2013

1970-1979 1980-1989 1990-1999

1940-1949 1950-1959 1960-1969
USDA Forest Service RMRS-GTR-325. 2014. 13

conditions required to consider managing a wildfire, 

such as specific calendar dates and a range of values 

for fire danger indices under which a wildfire could be 

managed. Additionally, early fire management plans 

in SNP highlighted the need for prescribed fire in the 

wilderness area to reduce fuels. With mechanical thinning not being an option in the Park or in wilderness 

areas, it was thought that prescribed fire in strategic 

locations would eventually allow for more use of managed wildfire. Prescribed fire was first implemented in 

the Park in 1984. Conversely, prescribed fire has not 

been implemented within the GALWC (although prescribed burning has occurred along the borders outside 

the wilderness), and managers have instead relied on 

natural ignitions to achieve their objectives.

Because the programs were initially conservative 

with respect to allowable burning conditions, acreage 

burned by managed wildfire and prescribed fire was 

modest in the early years (~1970-1990) (figure 16 and 

17). From 1970 to 1989, a combination of all fires 

in the GALWC covered a total of 88,805 acres, 90 

percent of those acres burned between 1985 and 1989 

Figure 15—Evidence and legacy of mid-1900s fires. Despite aggressive fire suppression policies, several fires still grew 

large in the Saguaro Wilderness Area and Gila Wilderness in the mid-1900s. Panel (a) shows a major fire burning in the 

Gila Wilderness in 1951. Panel (b) shows the effects of a 1943 wildfire near Mica Mountain in the Saguaro Wilderness 

(photo taken before 1957) (photographs courtesy of: (a) the Forest History Society, Durham, N.C., and (b) the National Park 

Service (from Dodge 1957)).

Figure 16—Area burned 

per year in the Gila and Aldo 

Leopold Wilderness Complex 

since 1909. The top panel shows 

annual area burned, and the 

bottom panel shows cumulative 

area burned in managed 

wildfires, suppression fires, and 

fires of “unknown” status (fires in 

which there was no information 

available in the database).

Vertical dashed line indicates 

first year of managed wildfire in 

1975. Prescribed fires have not 

occurred within these wilderness 

areas. The graph includes only 

fires greater than 100 acres.
14 USDA Forest Service RMRS-GTR-325. 2014.

(figure 12). The largest managed fire during this period was the 1989 Shelley Fire that burned over 10,000 

acres mostly within the wilderness boundary. Between 

1971 and 1989, several managed wildfires occurred in 

the SWA, but the vast majority were relatively small 

(figure 17). The two exceptions were managed wildfires in 1972 and 1988 that burned 820 and 420 acres, 

respectively on Mica Mountain. These fires were 

particularly important because they reburned areas 

east of Reef Rock that had already experienced four 

overlapping fires in the 1940s and 1950s, and which 

would burn again multiple times in the future (figure 

18). Additionally, the 1989 Chiva Fire was a suppression fire that started on Forest Service land but 

burned nearly 400 acres on Mica Mountain. In total 

more than 1,600 acres burned on in the SWA between 

1971 and 1989.

Large increases in prescribed fire and managed 

wildfire in both wilderness areas were not realized until the early 1990s and high rates of burning continued 

into the early 21st century. There are numerous reasons 

that this pattern developed. By 1998, policy and fire 

management plans were updated to allow for managed 

wildfire outside of wilderness areas in the GNF and 

managers began utilizing managed wildfire in other 

parts of the GNF, mostly in the Black Range Ranger 

District. Increased Federal investment in fuels treatments and fire management in general, including the 

adoption of the National Fire Plan (2000) in the early 

2000s, gave both units greater capacity to manage both 

Figure 17—Area burned per 

year in the Mica Mountain 

Study Area of Saguaro 

National Park since 1940. 

The top panel shows annual 

area burned, and the bottom 

panel shows cumulative 

area burned in managed 

wildfires, prescribed fires and 

suppression fires. Vertical 

dashed line indicates first year 

of managed wildfire in 1972. 

The graph includes only fires 

greater than 100 acres. *The 

1994 Rincon Fire was initially 

a managed wildfire, but was 

converted to a suppression fire 

after it spread toward the Park 

boundaries.

Figure 18—View of the east side of 

Reef Rock on Mica Mountain in the 

Saguaro Wilderness showing a small 

lightning fire that was suppressed 

in 2007. The relatively open forest 

structure of ponderosa pine forests in 

the foreground reflects the influence 

of 5 to 9 repeated fires in this area 

since 1943 (photograph courtesy of the 

National Park Service).
USDA Forest Service RMRS-GTR-325. 2014. 15

wildfire and prescribed fire. This included more funding for planning and implementing prescribed fire and 

access to Fire Use Modules (teams of fire professionals 

who specialized in implementing managed wildfire). 

Greater investment in prescribed fire ultimately provided more opportunities to utilized managed wildfire. 

For example, the Indian Peaks project in the GNF, in 

which 40,000 acres were treated with prescribed fire 

between 1999 and 2006, is seen as playing a pivotal 

role in allowing for the expansion of managed wildfire outside of the wilderness area in the Black Range. 

Prescribed fires on Mica Mountain in the SWA played 

similar roles. In addition, the accumulated experience 

with managed wildfire over decades allowed the organizations overall to be more comfortable and accepting 

of the practice.

In the GALWC, more than 219,000 acres burned 

between 1990 and 1999 with over 60 percent of these 

acres burning as part of managed fires. By the end of 

the 1990s more than 40 percent of the area within the 

GALWC had burned at least once since 1910 and more 

than 20 percent had burned multiple times (figure 14). 

The new millennium brought even more fire and the 

increase in area burned can be summarized in three distinct types of fires. The first type was a continuation of 

managed wildfires inside the wilderness area, the largest of which was the 2003 Dry Lakes Fire Complex 

that burned nearly 114,000 acres. The second fire type 

was large managed wildfires outside the wilderness. 

Examples of such fires include the 2005 Black Range 

Complex (74,274 acres), 2005 Fork fire (14,869 acres), 

and the 2007 HL fire (10,784 acres). The third fire 

type was large-scale prescribed fires outside the wilderness. The largest of these fires was the 2003 Boiler 

fire (56,695 acres) that burned in pine forests just north 

of the Aldo Leopold wilderness. As in prior decades, 

there were also a small number of fires that burned 

within high elevation mixed-conifer forests.

Patterns of severity of these fires varied, but fires in 

ponderosa pine forests tended to burn mostly with low 

severity while fires in mixed conifer forests tended to 

include more areas of high severity. For example, the 

1992 Creel fire (17,240 acres), 1993 Brush fire (39,348 

acres), 1993 Iron fire (5,825 acres) and 1997 Lilly fire 

(18,507 acres) all burned in ponderosa pine forest within the Gila wilderness and included less than 4 percent 

high severity within their perimeters (Iniguez 2014). 

These fires contained occasional patches of crown fire 

that created treeless patches as large as 300 acres. On 

the other hand the 1995 Bonner fire (26,380 acres) and 

the 1996 Lookout fire (14,200 acres) contained 18 percent and 11 percent high severity, respectively. These 

latter fires burned in higher elevation mixed-conifer 

forests; hence the mixed severity fire pattern was likely 

similar to historical fires in this landscape.

In the SWA, a total of 5,374 acres burned on Mica 

Mountain between 1990 and 1999 (figure 17). More 

than half of this total was from the 1994 Rincon Fire 

(3,281 acres) that was initially a managed wildfire; it 

was later converted to a suppression fire when it exceeded resource capabilities and burned toward U.S. 

Forest Service lands where management options were 

more limited. While most acreage occurred in suppression status, we classified it as a managed fire for the 

purpose of this report because it would have been suppressed at <1 acre had policy not been in place to allow 

lightning fires to burn. The rest of the acreage burned 

during this period was from prescribed fires, most of 

which were implemented in areas that had been burned 

in the prior decades. By the end of the decade nearly 

80 percent of the MMSA had burned at least two times 

since 1937 (figures 14). From 2000 to 2010 a total of 

2,500 acres had burned on Mica Mountain, of which 

about half was in the form of managed wildfires and 

the other half as suppression fires. The largest of the 

suppression fires was the Helens II fire in 2003, which 

burned mainly on the north slope of Mica Mountain 

through mixed conifer stands that had not burned during the last century.

Beginning in the mid- to late-2000s, a number of 

factors resulted in a decline in acreage burned in managed wildfire and prescribed fire in both the GAWLC 

and SWA (figure 16 and 17). This was driven in part by 

growing concern for the potential negative impacts of 

managed wildfire on valued resources, particularly under persistent drought conditions. Several suppression, 

managed, and prescribed fires during this period resulted in undesirable effects on habitat and populations 

of listed or sensitive species, including the Mexican 

spotted owl (Strix occidntalis lucida Nelson), the lowland leopard frog (Lithobates yavapaiensis Platz and 

Frost 1984), and the Gila trout (Oncorhynchus gilea 

(Miller)). In addition, some fires across the greater SWA spread into lower elevations in vegetation 

types not well adapted to fire; several saguaro cacti 

(Carnegiea gigantean (Engelm.) Britton & Rose), an 

iconic species and the namesake of the Park, were 

burned, along with other Sonoran desert species. There 

was also increasing concern about the spread of invasive grasses in the Sonoran desert, which might further 

encourage fire spread. In the GNF, there was growing 

concern for the impacts of fire on livestock range that 

was being impacted by severe drought. The capacity 

to implement prescribed fire in remote areas had also 
16 USDA Forest Service RMRS-GTR-325. 2014.

declined substantially toward the end of the 2000s; the 

cost of such projects had increased dramatically over 

the years and agencies directed most funds for fuels 

treatments to areas near the wildland urban interface. 

The last prescribed fire conducted in SWA was the 

2010 Mica Mountain prescribed fire. Only 114 acres of 

the 423-acre project area were burned because conditions became too dry, yet the burn cost approximately 

$300,000. Finally, managers in both study areas had 

found difficulty in expanding managed wildfire and 

prescribed fire programs to the “hard acres,” the steeper 

terrain and mixed conifer forests with heavy fuel loading where fires have greater potential to burn severely 

and have detrimental impacts to critical resources. Such 

areas comprised most of the remaining long-unburned 

areas by the beginning of the 21st century.

Figure 19—Fire frequency 

in the Gila Aldo Leopold 

Wilderness Complex from 

1909 to 2013. Most of the 

pine and mixed conifer forest 

in the GALWC have burned 

at least once; hence, most 

of the unburned areas are 

dominated by pinyon-juniper. 

Some areas in the interior of 

these two wilderness areas 

have burned as many as 

eight times since 1909.

Figure 20—Fire frequency in 

the Saguaro Wilderness Area 

in Saguaro National Park from 

1937 to 2013. Most of the area 

within the Mica mountain study 

areas has burned at least one 

and some areas have burned 

as many as nine times since 

1900.
USDA Forest Service RMRS-GTR-325. 2014. 17

Despite the successful reintroduction of prescribed 

fire and managed wildfire during this Era, there remain many areas within the SWA and the GALWC 

that have not burned in a century or more (figures 

19 and 20). The most notable in the SWA includes 

much of the area on Rincon Peak, which historically 

had fewer natural ignitions and slightly longer fire 

return intervals than Mica Mountain, and has had 

no prescribed fire (Iniguez and others 2009). More 

conservative approaches to fire management (suppressing more natural ignitions) on Rincon Peak have 

been taken in part because limited access and heavy 

fuels provide few options for managers to prevent 

fires from spreading to neighboring private property (figure 21). In addition, there has been resistance 

from resource staff in managing fires in Rincon Peak 

where there are sensitive resources, such as spotted 

owl populations. By 2010, long-unburned areas in the 

GALWC included the upper elevation mixed conifer, 

aspen, and spruce-fir forests in the Mogollon Range, 

which by the end of the 20th century, still hadn’t 

burned in over 100 years. Managers often attempted 

to utilize managed wildfire in these areas, but when 

lightning fires occurred they often burned during the 

monsoon season and remained small before going out 

on their own. Many wildfires were also suppressed in 

this system because of concerns about detrimental fire 

effects on Gila trout and Mexican spotted owl habitat. In addition, unlike at the SNP, fire managers have 

not utilized prescribed fire within the GNF wilderness 

area. Thus, mixed conifer forests have experienced 

relatively low rates of contemporary burning and 

may be more susceptible to larger, high intensity fires 

compared to what these forests would have experienced historically.

Megafire Era (2011 – present)

Very large and severe fires (~100,000+ acres) are 

projected to occur more frequently in the western 

United States as the climate becomes warmer and 

drier (Dillon and others 2012; Westerling and others 

2006). There is overwhelming evidence that many 

types of fuels treatments can be effective in mitigating the severity of wildfires (Fulé and others 2012). 

However, the degree to which fuels treatments (including managed wildfire and prescribed fire) will be 

effective in making forests more resilient to wildfire 

under future climates remains an open question and 

an important topic in need of additional research (see 

Appendix B). After more than a quarter century of 

reintroducing wildland fire in the GALWC, this landscape has been “tested” by a series of large wildfires 

since 2011. These fires have highlighted the benefits 

and potential limitations of the managed and prescribed fire program under relatively warm and dry 

climatic conditions. In particular, the 2011 Miller Fire 

(88,835 acres), the 2012 Whitewater Baldy Complex 

(297,845 acres, currently the largest wildfire in New 

Mexico State history), and the 2013 Silver Fire 

(133,625 acres) burned during severe and prolonged 

drought conditions through forests previously treated 

with prescribed fire and managed wildfire and through 

long-unburned forests.

Figure 21—View from Rincon Peak 

looking west toward the X-9 Ranch 

development. The steep terrain, 

accumulated fuels, and neighboring 

developments hamper fire managements 

in the Rincon Peak portion of Saguaro 

National park (photograph by Jose 

Iniguez, USDA Forest Service).
18 USDA Forest Service RMRS-GTR-325. 2014.

One thing that is evident from these fires is that 

the landscape mosaic created by previous prescribed, 

managed, and suppression fires provided options 

and opportunities to firefighters during suppression 

operations and that without that fire history, these suppression fires would have been much larger and more 

severe. For example, the spread of the Whitewater 

Baldy Complex (WWBC) was halted on the northeast 

by the 2006 Bear Fire and on the south by the Miller 

Fire. Firefighters were able to stop advancement to the 

north at the Eckleberger prescribed fire project area, 

an 18,000-acre burn on the Reserve Ranger District. 

Fewer resources were devoted to suppression on the 

eastern flank of the WWBC when it spread into Iron 

Creek Mesa, Jerky Mountain, and Lilly Mountain, 

where the WWBC was the third or fourth fire in the 

last 3 decades and was burning with low intensity. 

Similarly, the Silver Fire burned through previous fires 

with both low and high intensity, but it slowed and 

stopped to the north when it reached previous managed 

and suppression fires. The onset of “monsoon” conditions also helped stop the Silver Fire from spreading 

further.

Managed wildfire and prescribed fire can increase 

the resiliency of these forests to wildfire, even under 

severe drought conditions. In maps that overlay fire 

history and burn severity (figures 22 and 23), one can 

see that most of the areas that had previously experienced managed wildfire reburned with low to moderate 

severity in the Miller Fire and the WWBC. Overall, 

more than 64,000 of the 88,000 acres burned in the 

Miller Fire experienced at least one fire in the previous few decades. Most of the area classified as high 

severity had not burned in over a century; this included 

pinyon-juniper woodlands, pine stringers, and riparian areas that burned as the Miller Fire approached the 

West Fork of the Gila River. The WWBC and Silver 

Fire resulted in severe effects mostly in upper elevation 

mixed conifer forests that were also long unburned.

While the history of fires clearly impacted the 

spread and intensity of these suppression fires, it is also 

evident that previous fires were not always effective in 

mitigating fire severity. From the fire history and burn 

severity maps, it is clear that some areas classified as 

high severity had burned previously in managed wildfire (figures 22 and 23). Moreover, managers mentioned 

that all these fires seemed to result in fairly high tree 

mortality even as it passed through previously burned 

forests (figure 24). It is unclear, however, if the tree 

mortality is directly related to fire intensity, drought, 

or perhaps a combination of the two. Ultimately, the 

effects of subsequent fires likely depends on a large 

number of factors: how a fire burns into a stand, terrain and landscape context, fraction of total landscape 

treated, daily weather, seasonal drought, and fire management operations and tactics. More research into 

these and other factors that contributed to the high severity patches in these fires would further shed light on 

Figure 22—Map showing 

fire history and severity of 

the 2011 Miller Fire in the 

Gila National Forest. Most of 

the fire was low to moderate 

severity particularly within 

areas that had burned prior 

to 2011. Some of the areas 

that did experience high 

severity fires were pinyonjuniper stands that had not 

burned in the last century. 

Fire severity was derived from 

the Monitoring Trends in Burn 

Severity database (http://www.

mtbs.gov/).
USDA Forest Service RMRS-GTR-325. 2014. 19

the benefits and limitations of managed and prescribed 

fire under a changing climate (see Appendix B).

The fire program in SWA has not been recently tested 

in the same manner, because total area burned has been 

very low over the past several years. We speculate that 

a similar pattern might emerge should a fire start under 

Figure 23—Map showing fire history and severity of the 

2012 Whitewater Baldy Complex in the Gila National 

Forest. Fire severity was derived from the Monitoring 

Trends in Burn Severity database (http://www.mtbs.gov/).

severe drought conditions. In the areas where previous 

prescribed fires and managed wildfires have occurred, 

subsequent fires should be more likely to spread with 

lower intensity compared to long-unburned areas. 

However, unlike the GAWLC where burned area is increasing, about 10 years has passed since the last major 

Figure 24—Aerial view of the 

2011 Miller fire burning mostly 

as a low intensity wildfire within 

forested areas. The Miller fire also 

burned within and around nonforested patches (yellow/grass) 

created by prior more severe fires 

including the 2000 Bloodgood Fire 

and the 2003 Dry Lakes Complex. 

Patches of previous severe fires 

are now dominated by standing 

snags and grasses (photograph 

by U.S. Forest Service).
20 USDA Forest Service RMRS-GTR-325. 2014.

fire in SWA. Given that prescribed burning has also 

declined substantially in the Park, it remains unclear 

if resource management objectives will continue to be 

maintained in this landscape in the future with managed 

wildfires alone.

EFFECTS OF MANGED WILDFIRE 

AND PRESCRIBED FIRE

Over the last several decades, many research and 

monitoring studies have been conducted in these study 

areas in an attempt to understand the effectiveness of 

managed wildfire and prescribed fire in meeting management objectives and the effects of the practices on 

critical resources. This section summarizes what has 

been reported in the literature and sheds light on areas 

in need of further research (see Appendix B). Much of 

the existing literature focuses on the effects of these 

practices on (a) fuels, forest structure, and potential fire 

behavior, and (b) wildlife populations and habitat.

Fuels, Forest Structure, and 

Potential Fire Behavior

The effects of reintroduced fire on fuels, forest structure, and potential fire behavior vary by vegetation type 

and historical fire regime. For example, widespread low 

intensity fires would likely have occurred every 10 to 

30 years in juniper savannas (Margolis 2014). These areas have declined during the 20th century as a result of 

grazing and fire suppression. However, pinyon-juniper 

woodlands historically made up a much greater portion 

of the landscape (Miller 1999). In the woodlands, fires 

historically either burned very small areas (1-2 trees) or 

burned large areas as crown fires. This also appears to be 

how managed wildfires currently behave in this system 

(figure 25). In two recent wildfires in the GNF (2006 

Martinez and 2005 Johnson Fires), pinyon-juniper woodlands mostly burned as high intensity crown fires with 

almost complete overstory mortality (Hunter and others 2011). Even in pinyon-juniper woodlands that were 

classified as low severity in burn severity maps, often 

no evidence of fire was detected or if it was, it appeared 

that the fire impacted only 1 to 2 trees and logs in their 

immediate vicinity (Molly Hunter, personal observation 

of 2006 Martinez and 2005 Johnson Fires). Broadcast 

burning is not a common practice in these woodlands 

because fuels are generally not conducive to fire spread. 

Indeed, fire managers in the GNF often use pinyon-juniper woodlands as fuel breaks to slow or stop fire during 

prescribed fire and managed wildfire operations (Toby 

Richards, personal communication). However, recent 

wildfires have shown that many of these woodlands will 

support high intensity crown fire following a century 

of fire exclusion. While such fires may not be outside 

of the historical range of variability of fire behavior, it 

is unclear what the post-fire successional trajectories 

will be under current or future climates. Pinyon-juniper 

woodlands in other parts of the Southwest have shown 

the potential for novel successional trajectories due 

to spread of invasive species (Floyd and others 2006) 

and widespread mortality overstory induced by climate 

change (Breshears and others 2005).

The severity of managed wildfire and prescribed fire 

in ponderosa pine forests has tended to be more moderate. Studies in both the GWALC and SWA have shown 

that managed and prescribed fires were effective at reducing surface fuels and density of small trees while 

Figure 25—High severity burn 

in pinyon-juniper woodlands 

in the 2011 Miller Fire. Many 

of these woodlands tend to 

burn during periods of high 

winds and drought resulting 

in higher severity fires 

(photograph by Jose Iniguez, 

USDA Forest Service).
USDA Forest Service RMRS-GTR-325. 2014. 21

maintaining large trees (Holden and others 2007; Hunter 

and others 2011) (figure 26). This has resulted in stands 

that more closely resemble historical forest structure and 

are at lower risk of stand-replacing crown fire (Holden 

and others 2010; Hunter and others 2011). Areas that 

have previously burned in managed wildfires in the 

GAWLC tended to reburn with lower severity compared 

to previously unburned areas (Parks and others 2014). 

Furthermore, the cited studies show that those conditions 

can be effectively maintained after multiple managed 

wildfires have impacted an area (figure 27). One study 

showed that managed wildfire is slightly more effective 

Figure 26—Many ponderosa pine stands 

that have burned one or more times 

have more heterogeneous, open stand 

structures with lower densities of small 

trees. Stands such as this one in the Gila 

Wilderness should now exhibit a reduced 

probability of high severity fires in near 

future (photograph by Jose Iniguez, 

USDA Forest Service).

Figure 27—Open pine forests in the (a) Gila-Aldo 

Leopold, and (b) Saguaro Wilderness following 

multiple surface fires. Open forests in Iron Creek 

Mesa in the Gila Wilderness have experienced 

three surface fires since 1970 (1985, 2003, and 

2012) including burning most recently in the 2012 

Whitewater-Baldy fire. In Mica Mountain, this 

ponderosa pine stand (b) did not burn between 

1893 and 1942, but has since burned six times 

(two wildfires and four prescribed fires). Following 

a large increase in tree density during the fire 

exclusion gap in the early 1900s, the post-1942 

fires significantly reduced tree density and 

increased structural diversity and understory 

herbaceous cover (photographs by Jose Iniguez, 

USDA Forest Service (a) and Calvin Farris, 

National Park Service (b)).
22 USDA Forest Service RMRS-GTR-325. 2014.

than prescribed fire at reducing fuels and potential fire 

behavior (Hunter and others 2011). However, this study 

focused on first entry prescribed fires, which managers 

tend to ignite with cooler prescriptions to minimize detrimental effects and improve control. While no study 

has specifically examined the effects of multi-entry prescribed fire, managers in both areas are confident that 

they have achieved fuels objectives with repeated prescribed fire (figure 28).

Managed wildfires have been much less common 

in mixed conifer forests; when they have burned, they 

have tended to burn with higher severity compared to 

pine forests (Holden and others 2010). This may not be 

inconsistent with the historical fire regime, especially 

in the wetter, cooler mixed conifer types (Margolis 

and others 2011). In general, studies on the effects 

of prescribed fire and managed wildfire in mixed conifer forests in these areas are lacking in this region. 

However, Fulé and others (2004) found that a high intensity prescribed fire in mixed conifer forests in Grand 

Canyon National Park effectively reduced tree density 

and produced forest structures more closely resembling historical conditions. While studies on the effects 

of prescribed fire and managed wildfire on fuels, forest 

structure, and potential fire behavior have been studied 

in other parts of the country (for example, California), 

more studies in the Southwest are clearly needed (see 

Appendix B).

Figure 28—Examples of managed and 

prescribed fires in the Gila National Forest 

and Saguaro National Park. The 2002 

Cub Fire (a) is an example of a managed 

fire in the Gila National Forest. Panel 

(b) shows a ponderosa pine stand near 

the summit of Mica Mountain immediately 

following a prescribed burn in 2010. The 

burn was conducted as a maintenance 

burn in an area that had experienced four 

previous fires since 1943 (photographs by 

the U.S. Forest Service (a) and National 

Park Service (b)).
USDA Forest Service RMRS-GTR-325. 2014. 23

Threatened, Endangered, and 

Sensitive Species

In the last few decades, several local populations 

of the threatened Gila trout in the GALWC have been 

extirpated as a result of ash and debris flows following wildfires with large high severity patches on steep 

slopes (figure 29). Some examples include the 1989 

Divide Fire, the 1995 Bonner Fire, the 1996 Lookout 

Fire and more recent wildfires (Brown and others 

2001). Many populations of the Gila trout are geographically isolated, and opportunities for the fish to 

seek refuge and reestablish in recovered habitat after 

fires are limited. This has been exacerbated by low 

water levels during drought conditions. Thus, it has 

become common practice for fish to be removed from 

impacted streams when possible, and reintroduced 

when the habitat improves (Wood and Racher 2010). 

While widespread severe wildfire is known to be detrimental to the species, low intensity managed and 

prescribed fire may actually make Gila trout populations more resilient, especially if these fires result in 

reduced fuel loading and reduced risk of stand replacing wildfires in the future (Brown and others. 2001).

Aquatic Habitat and Species

Fires have also impacted aquatic species and habitat 

in the SWA. There are few perennial water sources in 

the SWA, and aquatic species rely in part on tinajas, 

or ephemeral pools that form in bedrock depressions. 

The lowland leopard frog, classified as a species of 

concern by the Arizona Game and Fish Department, is 

one of the species that relies on these pools (figure 30). 

Several tinajas filled with ash and sediment following 

the 1999 Box Canyon Fire and the 1989 Chiva Fire 

(Parker 2006). While water and frogs returned to some 

pools after a few years, some pools remained filled 

with sediment for up to 20 years. Severe fires have 

the greatest long-lasting impact on stream dynamics, 

sedimentation, and frog habitat. Thus there is concern 

that should fire spread through long-unburned portions 

of the SWA where fuel loading is uncharacteristically 

high, there could be further impacts on lowland leopard frog habitat.

Mexican Spotted Owl

The threatened Mexican spotted owl is adapted to 

fire-prone forests and uses a variety of forest conditions 

for feeding, nesting, etc. (figure 31). However, they 

rely particularly on closed forests with complex structure for nesting (USFWS 2012). These critical habitats 

exist both in pine forests within canyons and in denser 

mixed conifer forests. In the past, both managers and 

researchers have debated about using prescribed fire 

to reduce fuel loads within nesting areas as there was 

concern that fire could diminish key habitat features. 

However, some reduction in fuel loading is often desirable because stand replacing fires are seen as one of the 

biggest threats to the species (USFWS 2012). Extensive 

surveys have shown that low intensity prescribed fire 

Figure 29—The Gila trout is an endangered species found 

in streams within the Gila National Forest and is threatened 

by high intensity wildfire (photograph by R.C. Helbock, New 

Mexico Department of Game and Fish).

Figure 30—The lowland leopard frog is listed as a species 

of concern by the State of Arizona and is found in Saguaro 

National Park. The perennial pools that supply their habitat 

can fill with sediment following wildfire, but habitat and 

frogs have been found to return to some effected areas 

(photograph by Jim Rorabaugh, U.S. Fish and Wildlife 

Service).
24 USDA Forest Service RMRS-GTR-325. 2014.

and managed wildfire have minimal short-term impact 

on Mexican spotted owl occupancy or reproduction 

(Jenness and others 2004). However, several recent 

wildfires, such as the 2002 Helen’s II Fire in the SWA 

and the 2012 Whitewater-Baldy Complex in the GNF 

have burned severely in core owl habitat, particularly 

in mixed conifer forests (figure 32). Mexican spotted 

owls have high site fidelity so they will likely return to 

these sites particularly if patches of live forest remain 

(Willey 1998). However, there are fears because of low 

prey productivity and increased temperatures that the 

habitat will not be used by subsequent generation of 

Mexican spotted owl.

Wildlife Habitat and Populations

The fire programs in SNP and the GNF have had 

mostly positive or neutral impacts on non-listed wildlife species and their habitat. In the past, there have 

been concerns that frequent fire might deplete the snag 

population, which is a critical habitat feature for many 

wildlife species (Boucher and others 2000). Despite a 

decline in snag densities following a moderately intense 

fire in the Santa Catalina Mountains, they remained 

sufficient for wildlife habitat and bird populations remained stable (Ganey and others 1996). Snag densities 

also remained within recommended guidelines in areas 

that have burned multiple times in managed wildfire in 

the GALWC (Holden and others 2006).

There is also evidence that some species in particular have benefited from managed wildfire programs. 

For example, the buff-breasted flycatcher (Empidonax 

fulvifrons) is common in Mexico but its numbers declined in the mountains of southern Arizona and New 

Mexico starting in the late 1800s; some research suggests that fire exclusion may be partly responsible for 

the trend. Surveys have found the buff-breasted flycatcher associated with areas that recently burned in 

surface fire in the Rincon Mountains while they were 

not found on other mountain ranges in the region that 

had little to no evidence of recent fire (Conway and 

Kirkpatrick 2007). In addition, abundance of many 

other forest birds found in southwestern mountain 

ranges has been found to be higher in recently burned 

areas (Kirkpatrick and others 2006).

Figure 32—High severity burn patches following 

the 2002 Helens 2 Fire on the north slope of 

Mica Mountain. Historically, widespread fires 

burned across these north-slope warm/dry 

mixed conifer forests every 10-20 years prior to 

1886, but the area did not burn between 1886 

and 2002. The north slope of Mica Mountain 

was habitat for Mexican spotted owls. Although 

the fire severity was relatively heterogeneous, 

the long term impacts on the owl habitat are still 

unknown (photograph by National Park Service).

Figure 31—The threatened Mexican spotted owl is found in 

pine/oak and mixed conifer forests in both the Gila National 

Forest and Saguaro National Park. In some instances, 

managers have been successful in allowing spread of 

prescribed fire and managed wildfire in their habitat with 

minimal to beneficial effects. In other instances, managed 

wildfire and suppression fires have been detrimental to their 

habitat (photograph by Bill Radke, U.S. Fish and Wildlife 

Service).
USDA Forest Service RMRS-GTR-325. 2014. 25

CURENT CHALLENGES TO 

IMPLEMENTING MANAGED 

WILDFIRE

Their relative remoteness, inaccessibility, and history of frequent fire makes both of these study areas ideal 

for using fire as a restoration tool across broad landscapes. However, managers in both study areas still 

faced significant challenges managing wildfire and implementing large scale prescribed fire over the several 

decades of these programs. These challenges, which 

would likely be faced in other parts of the Southwest 

and the country, are described briefly here. In addition, 

we give examples of how managers in these study areas have worked to overcome these challenges.

Threatened and Endangered Species

There are several threatened and endangered species 

within SNP and the GNF that could be impacted by 

wildfire or prescribed fire: Mexican spotted owl, the 

lowland leopard frog, the Gila trout, and other species. Fire managers need to consider how their actions 

will affect these species. Managers often need to alter 

fire management practices during prescribed fire and 

managed wildfire to reduce potential threats to such 

species. Changed strategies and tactics could include 

altering the timing or intensity of fire, or restricting fire 

all together in sensitive areas. Managers in the GNF 

and SNP have overcome some of these challenges in 

particular by collaborating across disciplines and implementing rigorous monitoring programs.

Managers in the GNF for example have been successful in allowing fire to spread through Mexican 

spotted owl nesting habitat in pine forests with minimal 

and even beneficial effects to the species. In other parts 

of the Southwest, the default management strategy has 

been to avoid these areas altogether, which may ultimately be detrimental to the species if their core habitat 

cannot be made resilient to wildfire. The success in 

the GNF is partly attributed to collaboration between 

the fire staff and the natural resource staff that work 

closely together and recognize the importance of meeting objectives for both fuels and wildlife. Before every 

fire season both fire and non-fire personnel participate 

in a meeting where they strategize about where they 

might allow for managed wildfire in the upcoming fire 

season. Because of this close working relationship, fire 

managers understand what kind of fire and effects are 

desirable in sensitive areas and they can help achieve 

those effects. As a result, fire managers can make more 

informed decision on where, when, and how to manage 

fires.

SNP has invested a great deal in long-term monitoring to document the effects of fire on habitat and 

populations of lowland leopard frog to better understand the short- and long-term effects of fire on the 

species. Through these efforts, they have learned that 

leopard frog habitat can be severely degraded in the 

years following a high intensity wildfire and populations can subsequently disappear (Parker 2006). 

However, after several years frog populations have 

returned to some affected watersheds, indicating that 

refuge areas exist within the landscapes. Ultimately the 

monitoring results have provided further justification 

for the managed wildfire program; it has shown that 

fire management practices have likely increased resilience of frog populations in the long run.

Public Support for Fire Programs

Public support for fire programs is vital for their 

long-term success and there are many factors that 

can influence public opinion. For example, the public 

may not be supportive of fire programs if the inevitable smoke significantly impacts populated areas. 

However, the public is more likely to tolerate smoke 

if they recognize the benefits of less severe fires in the 

future. Other unintended consequences of prescribed 

fire and managed wildfire, such as escapes or impacts 

to recreation areas, can also influence public support. 

While some impacts to the public from fire are inevitable, minimizing impacts, engaging the public, and 

communicating the importance of fire can increase 

public support. Maintaining an active fire program is 

also important.

Managers in both study areas have invested a great 

deal in public outreach, which ultimately has increased 

public acceptance of prescribed fire and managed 

wildfire programs. Managers in both study areas take a 

variety of outreach approaches ranging from interpretive signs, putting information officers at visitor centers 

or other public venues, maintaining detailed websites 

to inform the public about individual incidents and the 

overall fire programs, and conducting educational programs in schools. They also work directly with local 

media outlets, which is why one can often find wellinformed and thoughtful stories on the fire ecology 

and management of the areas in both local and national publications. It is critical to devote resources to 

public outreach year round and to frame different messages at different times (before, during and after fires). 

Maintaining an active fire program is also important; 
26 USDA Forest Service RMRS-GTR-325. 2014.

having fire on the landscape each season (whether prescribed fire or managed wildfire) allows residents in 

the area to become accustomed to their effects, including smoke. A survey of local ranchers living near the 

GNF showed that many of these efforts have paid off; 

over two-thirds of respondents were supportive of the 

efforts of the GNF to manage wildfires and prescribed 

fires (Doug Boykin, personal communication).

Risk of Escape

There is always the potential for managed fires to 

spread beyond designated planning areas and impact sensitive resources or neighboring jurisdictions. 

This is a particular challenge in the SWA because it 

is a relatively small landscape surrounded by private, 

state, and Federal land managed by different agencies. 

Furthermore, the SWA boundaries are linear and do not 

follow any natural features that could be used to contain fires (figure 33). Any fire that starts in the SWA 

and grows to any measurable size is likely to spread 

beyond the Park’s boundaries. Therefore, most large 

wildfires in SWA have eventually been controlled on 

some flanks or suppressed completely because they 

threatened the border with the neighboring Coronado 

National Forest (CNF) and private lands. This is less 

of an issue in the GALWC, which is much larger than 

SWA; however, managers in the GNF must still contend with fire spreading beyond the agency boundaries. 

Outside of the wilderness areas, there are a number 

of private land inholdings throughout the forest and 

managers are challenged with minimizing the impact to 

these areas. For example the 2006 Skates Fire eventually had to be suppressed to prevent it from threatening 

a nearby community.

Managers in both areas have dealt with this challenge by collaborating with neighboring jurisdictions, 

both public and private. For example, SNP and the 

CNF developed a joint fire management plan, and a 

joint agency fire management officer oversees that 

plan. This has facilitated the sharing of resources and 

coordination of efforts across the agencies. In the GNF, 

managers worked with New Mexico State Forestry to 

develop agreements with private landowners in the 

area, mostly ranchers, to allow the GNF to manage 

wildfires on some private inholdings. These efforts allow for more effective and efficient management of 

wildfire as managers can take advantage of natural barriers for containment lines rather than trying to halt the 

spread of fire at fence lines.

Invasive Species

Spread of invasive species and their impact on fire 

spread patterns is becoming a significant challenge, 

particularly in SNP. Minimal fuels in Sonoran Desert 

habitats at lower elevations in the Park historically provide a barrier to fire spread from the higher elevation 

forests and woodlands. However, spread of invasive 

grasses such as buffelgrass (Pennisetum ciliare (L.) 

Link) at lower elevations has resulted in a more continuous fuel bed to support fire spread across these habitats 

Figure 33—Eastern boundary 

of Saguaro National Park. 

Saguaro National Park shares 

a boundary with the Coronado 

National Forest on the north, 

east and south, which often 

hampers the ability to manage 

fires due to the lack of 

natural barriers and differing 

levels of risk tolerance and 

management objectives. This 

image shows the eastern 

boundary, in close proximity to 

frequently burned ponderosa 

pine forests in the foreground) 

(photograph taken from Reef 

Rock looking southeast by 

Calvin Farris, National Park 

Service).
USDA Forest Service RMRS-GTR-325. 2014. 27

(figure 34). The potential for fire to spread in lower 

elevations could have significant impacts on many 

important native species in the Park that are not welladapted to fire, including the namesake saguaro cactus 

and many other species endemic to the Sonoran Desert. 

It may also result in more fires in higher elevations if 

continuous fuels allow fires to spread from lower elevation deserts (where human-caused ignitions are more 

common) to upper elevations woodlands and forests.

Multiple efforts are underway at SNP to combat the 

spread of buffelgrass. This includes treating hundreds 

of acres each year with herbicide or manual pulling, 

engaging in research and monitoring to inform treatment regimes, and public outreach. Research has 

shown that management efforts have been effective 

in slowing spread of the grass (Hunter 2012). In addition, managers at SNP are heavily engaged in a model 

collaborative effort to raise awareness about the threat 

of buffelgrass and coordinate volunteer and control efforts across southern Arizona (see www.buffelgrass.

org, last accessed 6/10/13).

Reintroducing Fire in Mixed to High 

Severity Fire Regimes

Managers in both areas have had difficulty reintroducing fires to areas that historically burned 

with mixed to high severity, namely pinyon-juniper 

woodlands and mixed conifer forests. When managed wildfire has been attempted in these systems 

they often either burn out on their own after impacting limited acreage, or burn as large, high intensity 

crown fires. While this pattern may not be inconsistent with what one would have seen historically, the 

high intensity fires in particular can be undesirable 

because of their potential to impact critical resources 

(such as threatened and endangered species) and may 

be difficult to control. Thus, many wildfires in mixed 

conifer forests have been suppressed during dry conditions because of concern for impacts on species like 

Gila trout and Mexican spotted owl. While these species obviously persisted under the historical mixed to 

high severity fire regimes, they are more threatened 

by contemporary high intensity fires given their low 

population numbers. Plus, recent fires in mixed conifer forests (for example, WWBC) have resulted in 

high severity patch sizes that are larger than historical 

estimates, possibly due to greater fuel homogeneity 

at landscape scales (Ellis Margolis, personal communication). In particular, it appears the high severity 

patches are burning both in dry and wet mixed conifer whereas historically high severity were relatively 

small and limited in dry mixed conifer forests (figure 

35). If fire is to be used as a tool in these systems, it is 

inevitable that some of it will be of high intensity and 

severity and it has been challenging to balance this 

fact with the protection of critical resources.

The GNF has attempted to address this challenge 

by experimenting with ways to reintroduce fire to 

mixed conifer forests. For example, a project was 

planned to introduce prescribed fire to a watershed 

occupied by Gila trout to reduce fuels and increase 

the resiliency of the population in the face of future 

wildfires. Unfortunately the project area was burned 

in the WWBC before the prescribed fire could be 

implemented. Other recent projects include the 2012 

Farm Flats Prescribed Fire, which covered approximately 2,000 acres of mixed conifer forests and was 

implemented in the fall to reduce fuels and protect 

a nearby community. Burning in the fall helped to 

achieve fuel reduction objectives while also keeping fire behavior within manageable levels. If fuels 

can be reduced in strategic locations to protect critical resources, then opportunities for use of some high 

Figure 34—Saguaro Cactus among a fuel bed of invasive 

grasses. Buffelgrass invasion of the lower elevations in 

Saguaro National Park has increased the connectivity of 

fuels across the landscape and can be detrimental to desert 

species that are not adapted to fire (photograph by Bethany 

Hontz, National Park Service).
28 USDA Forest Service RMRS-GTR-325. 2014.

intensity managed wildfire and prescribed fire may 

increase in other areas.

LESSONS LEARNED

Several factors facilitated the successful initiation 

of managed wildfire programs in the 1970s and their 

expansion over the last few decades. First the GAWLC 

and SWA represent relatively remote forested landscapes, making them ideal places to experiment with 

managed wildfire; while the SWA is not geographically remote, it is functionally remote due to limited 

access historically. Other important factors include 

the presence of vast fire-prone vegetation types, favorable climatic conditions, political environments 

that facilitated fire restoration, and the occurrence 

of mid-20th century wildfires that reduced fuel loads 

in many areas. The environmental and sociopolitical 

settings of these landscapes differ significantly from 

many other land management units throughout the 

West. Thus, we don’t necessarily expect the success 

of these programs to be replicated at similar scales 

everywhere using the same template. Nonetheless, 

there is much to be learned from these two programs that might be useful and applicable to other 

areas. Thus, we culminate this report by highlighting some of the key lessons that can be learned from 

these fire management programs. This list is by no 

means comprehensive or organized in order of importance. It simply represents recurring ideas and themes 

that emerged from the literature, the fire occurrence 

data, and discussions with managers throughout this 

project.

• Managed wildfire and prescribed fire can restore 

southwestern forests

• Managed wildfire, large-scale prescribed fire, and 

suppression fires create landscape fire mosaics that 

provide opportunities for fire managers

• Collaboration across disciplines and agencies is 

imperative

• Preparation and public outreach is critical

Managed Wildfire and Prescribed Fire 

Can Restore Southwestern Forests

Fire has been an effective restoration tool in the 

SWA and GAWLC to reduce fuels, restore forest and 

landscape structure, and reduce the potential for intense wildfire (particularly in the ponderosa pine 

dominated forests). Overall, both wilderness areas 

have burned considerably more during the 20th century than most other forested landscapes in the western 

United States. Within the SWA and GALWC there are 

extensive areas that have burned three or more times 

since the inception of the managed wildfire programs, 

Figure 35—High 

severity from the 2012 

Whitewater-Baldy fire. 

Although high severity 

fires are part of the 

historical fire regime 

in some mixed conifer 

forests, recent patches 

of high severity fire in 

the Gila National Forest 

may be larger due to fire 

exclusion, particularly 

in the dry/warm mixed 

conifer type (photograph 

by Jose Iniguez).
USDA Forest Service RMRS-GTR-325. 2014. 29

suggesting that current fire frequencies in these areas 

are closer to historic levels compared to other parts of 

the Southwest (figures 19 and 20). Although fires are 

still not as frequent or large as they were historically 

in most areas, studies have shown that areas where 

repeated managed wildfires have spread over several 

decades, forests more closely resemble historical conditions and are more resilient and resistant to wildfires 

under a variety of conditions. These findings suggest that managed wildfire and prescribed fire should 

be effective tools in other parts of the Southwest as 

well. Using fire as a restoration tool at large scales 

will likely be more difficult to implement in other 

landscapes that are less remote and more fragmented 

compared to these study areas. However, the opportunity for more use of managed wildfire and large-scale 

prescribed fire undoubtedly exists in the Southwest 

and is evident by the fact that we are beginning to 

see more use of these practices in a number of areas 

(for example, Kaibab, Tonto, Santa Fe, and Coconino 

National Forests).

Managed Wildfire, Large-Scale 

Prescribed Fire, and Suppression Fires 

Create Landscape Fire Mosaics That 

Provide Opportunities for Fire Managers

Acreage of fuels treatments in the western United 

States is currently dwarfed by wildfires and it is 

widely accepted that fuels treatments need to be dramatically scaled up to influence wildfire behavior and 

effects. Managers in both the GNF and SNP have 

been able to treat large areas with prescribed fire and 

managed wildfire relative to the size of their respective landscapes. Indeed, our analysis shows that a 

majority of each study area has been treated with fire 

at least once since the inception of the managed wildfire programs. This is in stark contrast to other forests 

in the Southwest where much of the landscapes remain untreated and long unburned, or has burned only 

through large suppression wildfires. One reason for 

this trend is that it is often more efficient to implement large-scale prescribed fire and managed wildfire 

because unlike mechanical treatments, their use is 

not restricted significantly by access or topography; 

however, mechanical treatments are not subjected to 

the same risks of escape or precision and have more 

predictable effects on stand structure. In addition, the 

absence of a robust wood products industry makes the 

use of fire less expensive on a per acre basis than mechanical treatments (Hunter and others 2007).

Over several decades, the numerous managed wildfires and prescribed fires in both areas have created a 

mosaic of historical burn scars across the landscape 

that have provided more strategic options during 

fire suppression events. Many examples of this were 

highlighted in this report where we discussed the effects of previous fires on the spread of the Miller Fire, 

WWBC, and Silver Fire in the GNF. For example, 

managers were able to use a previous prescribed burn 

to hold the 2012 WWBC to the north, and to devote 

fewer resources to suppression in the Iron Creek/Lilly 

Mountain area where the fire was spreading through 

areas burned previously by multiple managed wildfires (figure 23). Managers in SNP similarly believe 

that the prescribed fire and managed wildfire program 

slowed and reduced fire intensity of the 2003 Helen’s 

II Fire where it met previous burns.

Prescribed fire, managed wildfire, and suppression 

wildfires can facilitate the increased use of fire as a 

restoration tool. For example, a strong prescribed fire 

program allows managers to develop fire management 

skills, reduce fuels on the landscape, and allows the 

public and resource specialists to become comfortable 

with fire and its effects. These are all factors that will 

ultimately facilitate the increased use and success of 

managed wildfires. The same is true of the influence 

of managed wildfire on a prescribed fire program. 

For example, in SNP, the 1994 Rincon Fire reduced 

fuel loads and provided holding lines for prescribed 

fires in subsequent years, which is partly why the prescribed burning program was able to expand in the 

mid- to late-1990s. In addition, large-scale prescribed 

burning (for example, Indian Peaks project) allowed 

for managed wildfires to extend beyond the wilderness boundary in the Black Range. Thus in both areas, 

it is evident that a patchwork of large-scale fires on 

the landscape can aid all aspects of fire management.

The contribution of suppression fires can also be 

important for facilitating the use of future prescribed 

or managed fires, as is illustrated by the early 1950s 

fires in both wilderness areas (figures 12 and 13). 

Both fire programs have taken advantage of past burn 

scars to provide opportunities to implement future 

fires. By utilizing all types of fire available, a holistic 

fire landscape puzzle is created where each fire supports additional use of fire on the landscape. While 

the recent megafires that have occurred throughout 

the Southwest have had detrimental effects on some 

ecosystems and communities, they should also be 

thought of as opportunities and utilized for the safe 

reintroduction of beneficial fire on the landscape.
30 USDA Forest Service RMRS-GTR-325. 2014.

Collaboration Across Disciplines and 

Agencies Is Imperative

Agencies are tasked with managing land for multiple objectives and protecting a variety of resources. 

At times, management actions that reduce fire risk can 

conflict with other objectives. For example, a managed 

wildfire may achieve objectives for reducing fuels and 

restoring fire as an ecological process, but it might also 

threaten populations of sensitive aquatic species in 

ways not experienced in the past (for example, leopard 

frog). Thus, within an agency, it is imperative to constantly communicate and collaborate across disciplines 

to assure that managed wildfire and prescribed fire 

seek to achieve multiple objectives and minimize adverse impacts. It is also essential to work closely with 

people in neighboring jurisdictions, because fire and 

smoke do not obey property lines. Managed wildfires 

can get quite large and a program is not likely to be 

successful if fires aren’t able to spread across multiple 

jurisdictions.

There are several examples of successful collaboration across disciplines and agencies in both study 

areas: annual meetings among fire and non-fire personnel in the GNF, the joint fire management plan 

between SNP and the neighboring Coronado National 

Forest, and partnerships between Federal and private 

landowners in the GNF to manage wildfire on both jurisdictions. Managers in both areas have stressed that 

collaboration tends to facilitate rather than restrict use 

of managed wildfire across their landscapes.

Preparation and Public 

Outreach Is Critical

Both fire programs have had active and inactive 

periods of burning due to external and internal factors. Events external to the organization like the Cerro 

Grande Fire—escaped prescribed fire that burned part 

of the town of Los Alamos, New Mexico—or widespread budget cuts can effectively shut or slow down 

a fire program. Conversely, policy initiatives like 

the National Fire Plan (2000) can greatly increase 

capacity in fire management programs by allowing agencies to hire more fire related personnel for 

implementation, monitoring, and planning managed 

and prescribed fire. Internally, personnel changes can 

influence the activity of a program, particularly when 

new personnel are not familiar or comfortable with 

the risk that comes with using fire as a restoration tool. 

It is inevitable that external and internal factors will 

influence the activity of a fire program, but investing 

in preparation, both short- and long-term, and public 

outreach can help managers weather those factors and 

maintain fire programs through inactive periods.

In the short-term, pre-fire season preparation and 

collaboration can greatly increase of a manager’s ability to use managed wildfire in any given season. One 

example of this preparation is the annual meetings 

with fire and non-fire personnel in the GNF where 

they discuss potential locations to manage wildfire 

given what is known about sensitive resources, fuel 

conditions, outlooks, and the recent fire history. Since 

much of the analysis and discussion is done before a 

fire starts, decisions regarding fire strategies can be 

made relatively quickly in the event of an ignition. 

This type of short-term preparation has allowed the 

GNF to take advantage of natural ignitions when they 

occur in the areas where managed wildfire has been 

deemed a viable option. Similar planning strategies 

have been adapted by other successful fire programs, 

such as Grand Canyon National Park and others.

In the long-term, investments in monitoring, planning, and training for personnel can greatly bolster 

fire programs. Even basic inventory monitoring provides a good understanding of the fuels, fire history, 

and sensitive resources in an area, which is needed 

to decide where use of managed wildfire is most appropriate on a landscape. Monitoring information can 

also be used for public outreach to justify and gain 

support for increased fire activity. Planning then provides the policy and legal basis for managing wildfire 

and prescribed fire. Organizations also need ready access to staff qualified to implement managed wildfire. 

Having all these pieces in place allows managers to 

take full advantage of favorable climates for managed 

wildfire or prescribed fire when they do occur. For 

example, both the GNF and SNP were able to take 

advantage of resources allocated in the National Fire 

Plan (2000) because they already had the planning, 

information on current conditions, and qualified personnel in place to implement managed wildfire and 

large-scale prescribed fire. This is partly why the prescribed fire and managed wildfire programs were able 

to accomplish so much in the early 2000s.

Finally, public outreach plays a critical role in 

alleviating external factors that can influence fire programs in the short- and long-term. Managers from 

both units mentioned that public outreach has played 

an important role in acceptance of smoke and other effects that result from the fire programs. For example, 

in the GNF the 2006 Skates Fire forced the evacuation 

of a small community, yet evacuees remained mostly 

supportive of the overall fire program and understood 
USDA Forest Service RMRS-GTR-325. 2014. 31

the need for managed and prescribed fire. This was a 

testament to the year-round investment in public outreach by the GNF. In SNP the active engagement of 

community volunteers, especially in buffelgrass control efforts, can be attributed to the investments SNP 

has made in public outreach.

CONCLUSION

All three lines of evidence we explored for this 

report support the idea that managed wildfire and prescribed fire programs have been largely successful and 

beneficial in meeting resource management objectives 

where it has been applied in the GALWC and SWA. 

Managers from both sites have overcome significant 

challenges in implementing managed wildfire and 

large-scale prescribed fire, providing us with lessons 

that may be applied to other parts of the country. Still, 

even in these relatively remote landscapes, there are 

areas where the challenges of implementing managed wildfire and prescribed fire have been too great 

to overcome. Thus, managed wildfire will likely always need to be utilized in a larger fuels management 

framework that includes prescribed fire and other treatments. While we recognize that managed wildfire and 

prescribed fire cannot be applied everywhere, there are 

likely opportunities to increase their use in many parts 

of the West. In fact many management units throughout the Southwest, (for example, Kaibab, Santa Fe, and 

Coconino National Forests) are increasingly adopting 

the practice.

These two wilderness areas provide examples 

of how fires can effectively be used to restore landscape-scale forest structure and increase resiliency to 

wildfire. However, successfully restoring landscapes 

will require patience (decades) and an understanding 

that fire will inevitably result in some undesired effects. 

Current fire managers face a set of increasingly difficult conditions: heavy fuel loads, warming temperature 

and prolonging drought. It is no longer a question of 

whether a given tract of forest will burn or not; rather, 

the decision managers must now make is, when and 

how forests will burn, knowing full well that suppressing fires now only postpones the inevitable. Therefore 

it is in the best interest of the public and future generations to make greater use of fire as a restoration tool to 

create more resilient and resistant forest ecosystems.

ACKNOWLEDGMENTS

This project was supported in part by National Fire 

Plan funds provided by the Aldo Leopold Wilderness 

Research Institute for the U.S. Forest Service Rocky 

Mountain Research Station. We thank all the managers who provided valuable insight in fire management 

in these study areas (see Appendix A). We also thank 

Art Telles, Gabe Partido, and Martha Schumann who 

helped organize a field tour of the Whitewater Baldy 

Complex. Finally, we thank all those who provided 

detailed reviews of the report: Bob Lineback, Marcia 

Andre, Zach Holden, and Todd Erdody.

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USDA Forest Service RMRS-GTR-325. 2014. 35

GLOSSARY

Confine: The least aggressive wildfire suppression 

strategy that can be expected to keep a wildfire within 

predetermined natural or artificial boundaries under 

prevailing conditions.

Contain: A moderately aggressive wildfire suppression strategy that can be expected to keep a wildfire 

within predetermined artificial or natural boundaries 

under prevailing conditions.

Fire intensity: The rate of energy release from the 

flaming front of a fire.

Fire regime: A depiction of the role of fire in an ecosystem. It often includes descriptions of fire frequency, 

intensity, size, severity, and seasonality.

Fire severity: An indicator of the ecological impact of 

fire on a particular resource. In this report, fire severity 

is mostly referring to the effects of fire on dominant 

tree mortality.

Forest composition: All the plant species found in a 

forested stand or landscape.

Forest structure: The living and non-living physical 

components, and their spatial arrangement, within a 

forested ecosystem.

Fuels: Any living or dead vegetation that will burn. 

It can include coarse wood, litter, duff, grasses, forbs, 

shrubs, and trees.

Fuels treatment: The manipulation or removal of fuels with the intent to reduce the probability of ignition 

and/or to lessen potential fire intensity, severity, and 

resistance to control. Fuels manipulation and removal 

can be done with prescribed fire, managed wildfire, or 

with mechanized equipment.

Managed wildfire: A term used in this report to describe naturally ignited fires that are managed with 

minimal suppression and allowed to spread to meet 

resource objectives.

Mean fire return interval (MFI): The average number of years between fires for a specified area and time 

period.

Mechanical treatment: Any fuels treatment that uses 

mechanized equipment (i.e. chainsaws, masticators, 

tree harvesters) to remove or redistribute fuels for the 

purpose of reducing the probability of ignition and/

or to lessen potential fire intensity, severity, and resistance to control.

Megafire: A wildfire that burns under fuels and/or 

climatic conditions that results in extraordinary fire behavior characteristics, size, complexity, and resistance 

to control.

Natural fire rotation (NFR): The average time required to burn an area equivalent to the size of the 

entire study area.

Prescribed fire: A fire intentionally ignited by managers to meet specific resource objectives.

Prescribed natural fire: A previously used term (pre 

1995) to describe lightning fires that are allowed to 

burn to benefit resources.

Resilience: The capacity of an ecosystem to recover 

from a disturbance (e.g. wildfire) and retain essentially 

the same function, structure, identity, and feedbacks.

Resistance: The capacity of an ecosystem to weather 

a disturbance (e.g. wildfire) without significant change 

in function, structure, identity, and feedbacks.

Restoration: The process of assisting the recovery 

of ecosystems that have been degraded, damaged, or 

destroyed.

Suppression: The act of extinguishing or confining a 

wildfire.

Suppression fire: A term used in this report to describe 

any unwanted fire that is actively suppressed.

Tinajas: Ephemeral pools of water that form in bedrock depressions. These are particularly prevalent and 

important ecological features in Saguaro National Park.

Wildland fire use: A previously used term (pre 2009) 

to describe lighting fires that are allowed to burn to 

benefit resources.
36 USDA Forest Service RMRS-GTR-325. 2014.

Managers that we interviewed for input in this report. Interviews were conducted by telephone, email, or in 

person.

Craig Allen, US Geological Survey, Research Ecologist

Marcia Andre, Gila National Forest, Supervisor (retired)

Doug Boykin, New Mexico State Forestry, District Forester

Liz Carver, Gila National Forest, Forestry Technician

Pete Delgado, Gila National Forest, Fuels Specialist

Todd Erdody, National Park Service, Lead Fire Effects Monitor

Albert Flores, Gila National Forest, Fuels Specialist

Robert Gallardo, Gila National Forest, Fire Management Officer

Perry Grissom, Saguaro National Park, Fire Ecologist

Gabe Holguin, Gila National Forest, Fire Management Officer

Emily Irwin, USDA Forest Service, Region 3 Program Manager (formerly with Gila National Forest)

Carolyn Koury, Gila National Forest, Hydrologist

Bob Lineback, National Park Service, Regional fire manager (retired) and Incident manager

Ellis Margolis, University of Arizona, Research Associate

Pat Morrison, Gila National Forest, District Ranger

Shilow Norton, Gila National Forest, Fire Management Officer

Gabe Partido, Gila National Forest, Fuels and Vegetation Program Manager

John Pierson, Gila National Forest, District Ranger

Toby Richards, Gila National Forest, Assistant Fire Management Officer

Kathy Schon, USDA Forest Service, Washington Office, Fire Ecologist (formerly with Saguaro National Park)

Martha Schumann, The Nature Conservancy, Southwest New Mexico Field Representative

Chuck Scott, Saguaro National Park, Fire Management Officer (retired)

Art Telles, Gila National Forest, Biologist

APPENDIX A: MANAGERS INTERVIEWED
USDA Forest Service RMRS-GTR-325. 2014. 37

In conducting the literature review and conversations with managers, it became apparent that there is 

need for more research on several topics. The most 

pressing needs for research relevant to fire and fuels 

management in these study areas are (1) effects of 

high intensity fire, (2) mortality of drought-stressed 

trees, (3) effectiveness and effects of post-fire seeding, (4) effectiveness of fuels treatments under current 

and changing climatic conditions, (5) effects and effectiveness of prescribed and managed fire in poorly 

understood systems, and (6) limitations of using natural ignitions to achieve objectives.

Effects of High Intensity Fire

Wildfires with large (>500 acre), high severity patches have recently occurred in the GNF in particular and it 

is unclear how succession will proceed given the size of 

the patches and current and future climatic conditions. 

High severity patch size can influence opportunities 

for pine and conifer recruitment from surviving seed 

sources (Haire and McGarigal 2010). Drought may 

also make conditions unfavorable for pine and conifer 

regeneration. This may mean that sprouting species 

such as gamble oak and aspen dominate for a while; 

however, interactions with other disturbance agents 

(i.e. insects, disease, browsing, and drought) may influence their persistence. In general, there is uncertainty 

for how succession will proceed in the short- and longterm in areas impacted by large and intense wildfires, 

and how interacting disturbances such as drought and 

introduction of invasive species might influence the 

trajectory of succession. Alternative succession trajectories will undoubtedly have implications for wildlife 

populations that rely on these forests for habitat. Thus, 

research is needed on short- and long-term succession 

and implications for wildlife populations and habitat 

following large-scale, high intensity fire.

Mortality of Drought-Stressed Trees

Managers in both areas have expressed concern 

that tree mortality from low intensity fire seems to be 

higher when trees are drought-stressed. There is some 

evidence for this phenomenon in forests throughout 

the West (van Mantgem et al. 2013). However, little 

is known about the mechanisms responsible for this 

APPENDIX B: RESEARCH NEEDS

trend. More research is needed on the interactions 

between drought and low-intensity fire-induced tree 

mortality. Such research could inform management 

decisions on the appropriate timing and application 

of prescribed fire and managed wildfire under drought 

conditions.

Effectiveness and Effects of Post-Fire 

Seeding

Studies throughout the West have suggested that 

post-fire seeding in high severity areas for the purpose 

of reducing the potential for soil erosion is often ineffective (Peppin et al. 2010). For a number of reasons, 

seeded grasses often become sufficiently established to 

reduce erosion potential. However, managers in these 

study areas have long speculated that given different 

climatic conditions in southwestern forests, appropriate 

application of grass seed can produce effective results. 

Indeed, post-fire seeding of the WWBC seemed to produce high grass cover in seeded areas (Molly Hunter, 

personal observation of the WWBC). Thus, managers 

highlighted the need for research in post-fire seeding 

effectiveness and effects, particularly in southwestern 

forests where precipitation from summer “monsoonal” 

storms may facilitate greater grass establishment.

Effectiveness of Fuels Treatments 

Under Current and Changing Climatic 

Conditions

While there was certainly evidence that severity 

of the recent megafires in the GNF was mitigated by 

previous managed wildfires and prescribed fires, these 

fuels treatments were not universally effective in reducing fire behavior and effects, perhaps a result of 

the severe drought conditions under which these fires 

burned. Fuels treatments are not designed to be effective in lessening fire behavior under all possible 

conditions and we might expect their effectiveness to 

be more limited as the climate becomes warmer and 

drier. To that end, more research is needed to investigate the degree to which a variety of fuels treatments 

will be effective under current and future climatic conditions. Such research should consider the multitude 

of factors that might influence treatment effectiveness 
38 USDA Forest Service RMRS-GTR-325. 2014.

(i.e. fuels, weather, terrain, area treated, type and age 

of treatment). 

Effects and Effectiveness of Prescribed 

and Managed Fire in Poorly Understood 

Systems

Much of the research conducted on effects and effectiveness of prescribed fire and managed wildfire has 

focused on ponderosa pine forests. This is not surprising, given that fire management programs have focused 

more heavily in these systems. Recently however, 

large fires have impacted pinyon-juniper woodlands 

and mixed conifer forests with variable severity. These 

fires have provided opportunities to examine basic fire 

effects in these systems. Pinyon-juniper woodlands 

and mixed conifer forests have been the subject of research studies in other parts of the country, but they 

remain under-studied in the Southwest, particularly in 

the southern portion of their range. 

Limitations of Using Natural Ignitions to 

Achieve Objectives

Managers in the SWA and GALWC have been able 

to burn an impressive number of acres with managed 

wildfire. However, many areas in both units remained 

unburned decades after the inception of these programs. 

Examples include higher elevation mixed conifer forests in the GAWLC and Rincon Peak in the SWA. 

This begs the question: Can landscapes be made more 

resilient to wildfire using managed wildfire alone? 

Prescribed fire has not been used in the GAWLC, but 

managers have recently considered implementing the 

practice. Prescribed fire has been a very important tool 

in the SWA in the last few decades, but it is not used 

currently because funds for National Park Service fuels 

programs have been directed to areas closer to wildland urban interface. Modeling studies that examine 

fire ignition and spread patterns would inform managers on what accomplishments could be expected using 

managed wildfire and prescribed fire. 

United States Department of Agriculture

Forest Service

Rocky Mountain Research Station

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