-
United StatesDepartmentof Agriculture
Forest Service
Rocky MountainResearch Station
ProceedingsRMRS-P-15-VOL-5
September 2000
Wilderness Science in aTime of Change ConferenceVolume 5:
Wilderness Ecosystems,Threats, and ManagementMissoula, MontanaMay
23–27, 1999
-
AbstractCole, David N.; McCool, Stephen F.; Borrie, William T.;
O’Loughlin, Jennifer, comps. 2000.
Wilderness science in a time of change conference—Volume 5:
Wilderness ecosystems, threats,and management; 1999 May 23–27;
Missoula, MT. Proceedings RMRS-P-15-VOL-5. Ogden,UT: U.S.
Department of Agriculture, Forest Service, Rocky Mountain Research
Station. 381 p.
Forty-six papers are presented on the nature and management of
threats to wildernessecosystems. Five overview papers synthesize
knowledge and research on wilderness fire,recreation impacts,
livestock in wilderness, nonnative invasive plants, and wilderness
air quality.Other papers contain the results of specific research
projects on wilderness recreation impactsand management, wilderness
restoration, fire and its management, and issues related to
air,water, and exotic species.
Keywords: air quality, campsites, fire, fish stocking, invasive
species, livestock, recreation impact,restoration, trails
RMRS-P-15-VOL-1. Wilderness science in a time of change
conference—Volume 1:Changing perspectives and future
directions.
RMRS-P-15-VOL-2. Wilderness science in a time of change
conference—Volume 2:Wilderness within the context of larger
systems.
RMRS-P-15-VOL-3. Wilderness science in a time of change
conference—Volume 3:Wilderness as a place for scientific
inquiry.
RMRS-P-15-VOL-4. Wilderness science in a time of change
conference—Volume 4:Wilderness visitors, experiences, and visitor
management.
RMRS-P-15-VOL-5. Wilderness science in a time of change
conference—Volume 5:Wilderness ecosystems, threats, and
management.
Cover art by Joyce VanDeWater, Rocky Mountain Research
StationConference symbol designed by Neal Wiegert, University of
Montana
You may order additional copies of this publication by sending
yourmailing information in label form through one of the following
media.Please specify the publication title and number.
Telephone (970) 498-1392FAX (970) 498-1396
E-mail [email protected]
Mailing Address Publications DistributionRocky Mountain Research
Station240 West Prospect RoadFort Collins, CO 80526
-
Compilers
David N. ColeStephen F. McCoolWilliam T. BorrieJennifer
O’Loughlin
Wilderness Science in a Timeof Change Conference
Volume 5: Wilderness Ecosystems,Threats, and Management
Missoula, MontanaMay 23-27, 1999
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ii
CompilersDavid N. Cole is Research Biologist with the Aldo
Leopold Wilderness Research Institute,Rocky Mountain Research
Station, located on The University of Montana campus in
Missoula,MT. Dr. Cole has A.B. and Ph.D. degrees in geography from
the University of California,Berkeley, and the University of
Oregon. He has been conducting research on wilderness andits
management since the mid-1970’s.
Stephen F. McCool is Professor, Wildland Recreation Management,
at the School of Forestry,The University of Montana in Missoula,
MT. He holds a B.S. degree in forestry from the Universityof Idaho
and M.S. and Ph.D. degrees from the University of Minnesota. His
research andapplications projects concern wilderness and protected
area management and planning, focusingon management systems,
applications of social science to management, public participation,
andsustainability questions.
William (Bill) T. Borrie is Associate Professor and Program
Coordinator, Outdoor RecreationManagement, in the School of
Forestry, The University of Montana. Dr. Borrie received a
Ph.D.from the College of Natural Resources, Virginia Tech, and has
masters and bachelors degreesfrom the School of Forestry,
University of Melbourne, Australia. His research interests are
focusedon the outdoor recreation experience and on the meanings of
parks and wilderness.
Jennifer O’Loughlin holds a B.A. in journalism and history and
an M.S. in environmental studiesfrom the University of Montana.
After serving for 10 years as editor of the natural resource
journalWestern Wildlands, she turned to a life of free-lance
writing and editing.
The use of trade or firm names in this publication is for reader
information and does notimply endorsement by the U.S. Department of
Agriculture of any product or service.
The USDA Forest Service is not responsible for statements and
opinions advanced in thispublication. Authors are responsible for
the content and quality of their papers.
CAUTION:PESTICIDES
Pesticide Precautionary Statement
This publication reports research involving pesticides. It does
notcontain recommendations for their use, nor does it imply that
the usesdiscussed here have been registered. All uses of pesticides
must beregistered by appropriate State and/or Federal agencies
before they canbe recommended.
CAUTION: Pesticides can be injurious to humans, domestic
animals,desirable plants, and fish or other wildlife—if they are
not handled orapplied properly. Use all pesticides selectively and
carefully. Followrecommended practices for the disposal of surplus
pesticides andpesticide containers.
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iii
The Wilderness Science in a Time of Change Confer-ence was held
in Missoula, Montana, May 23 through27, 1999. The conference was
conceived to be both afollowup and an expansion of the first
National Wil-derness Research Conference, held in Fort
Collins,Colorado, in 1985. That conference brought togethermost of
the scientists in the world who are working onissues related to the
management of wilderness andresulted in literature reviews and
compilations ofresearch that remain critical references today
(Lucas1986, 1987). Our intent was to bring scientists to-gether
again, along with wilderness managers, toproduce an updated
compendium of the current state-of-knowledge and current research.
In addition, wesought to increase the array of scientific
disciplinesrepresented at the conference and to expand the rangeof
topics beyond the challenges of managing wilder-ness. Finally, we
hoped to use plenary talks to high-light controversy, divergent
viewpoints, and manage-ment dilemmas—to challenge participants’
beliefsystems—in the hopes that this would stimulate inter-action
and personal growth.
Well over 400 people participated in the conference.Conference
attendees included a roughly equal mix ofpeople from federal land
managing agencies and fromacademia. There were also several
representativesfrom state, local, and tribal governments. There
weremore than 30 attendees from 16 different nongovern-mental
organizations, as well as a number of privateindividuals,
consultants, and members of the press.About 20 participants were
from Canada, with about20 more participants from other countries.
We suc-ceeded in attracting people from diverse disciplines,united
in their interest in wilderness. As usually is thecase, a large
proportion of the researchers who at-tended specialize in the
social science aspects of out-door recreation. However, attendees
also includedother types of social scientists, philosophers,
paleon-tologists, and life scientists interested in all scales
ofanalysis from cells to the globe.
The conference consisted of plenary talks to bepresented before
the entire conference, as well as morenarrowly focused
presentations organized around threeconference themes and presented
in concurrent ses-sions. The conference’s plenary talks were
organizedinto four sessions: (1) global trends and their
influenceon wilderness, (2) contemporary criticisms and
cel-ebrations of the idea of wilderness, (3) the capacity ofscience
to meet the challenges that wilderness facesand to realize the
opportunities that wilderness pre-sents, and (4) concluding talks
related to conferencethemes.
The bulk of the conference was organized aroundthree themes. The
first theme was “Science for Under-standing Wilderness in the
Context of Larger Sys-tems.” The emphasis of this theme was better
under-standing of the linkages between wilderness and thesocial and
ecological systems (regional, national, andinternational) in which
wilderness is situated. Theemphasis of the second theme,
“Wilderness for Sci-ence: A Place for Inquiry,” was better
understanding ofwhat we have learned from studies that have
utilizedwilderness as a laboratory. The third and most tradi-tional
theme was “Science for Wilderness: ImprovingManagement.” The
emphasis of this theme was betterunderstanding of wilderness
visitors, threats to wil-derness values, and means of planning for
and manag-ing wilderness.
We organized three types of sessions under each ofthese three
themes. We invited 18 speakers to presentoverview papers on
specific topical areas under eachtheme. Many of these speakers
developed comprehen-sive state-of-knowledge reviews of the
literature fortheir assigned topic, while others developed
moreselective discussions of issues and research they judgedto be
particularly significant. In addition, conferenceparticipants were
given the opportunity to contributeeither a traditional research
paper or to organize adialogue session. Most of the research papers
(131papers) were presented orally, but 23 additional pa-pers were
presented in a poster session. The 14 dia-logue sessions were
intended to promote group discus-sion and learning.
The proceedings of the conference is organized intofive separate
volumes. The first volume is devoted tothe papers presented during
the plenary sessions.Subsequent volumes are devoted to each of the
threeconference themes, with two volumes devoted to wil-derness
management, the theme with the most pa-pers. Within each theme,
papers are organized intooverview papers, research papers, and
papers fromthe dialogue sessions. The format of dialogue
sessionpapers varies with the different approaches taken tocapture
the significant outcomes of the sessions. Re-search papers include
papers presented orally and onposters. Within each theme, research
papers are orga-nized into broad topical areas. Although the
initialdraft of each proceedings paper was reviewed andedited,
final submissions were published as submit-ted. Therefore, the
final content of these papers re-mains the responsibility of the
authors.
We thank the many individuals and institutions onthe lists of
committee members and sponsors that
Preface
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iv
follow. They all contributed to the success of
theconference.
Planning Committee: Joan Brehm, Perry Brown,David Cole, Wayne
Freimund, Stephen McCool, ConnieMyers, and David Parsons.
Program Committee: David Cole (Co-chair), StephenMcCool
(Co-chair), Dorothy Anderson, William Borrie,David Graber, Rebecca
Johnson, Martha Lee, ReedNoss, Jan van Wagtendonk, and Alan
Watson.
Sponsors: Aldo Leopold Wilderness Research Insti-tute; Arthur
Carhart National Wilderness TrainingCenter; Bureau of Land
Management; Forest Service,Research; Forest Service, Rocky Mountain
ResearchStation; Humboldt State University, College of Natu-ral
Resources; National Outdoor Leadership School;National Park
Service; Parks Canada; State Univer-sity of New York, Syracuse,
College of EnvironmentalScience and Forestry; The University of
Minnesota,Department of Forest Resources; The University ofMontana,
School of Forestry, Wilderness Institute;U.S. Fish & Wildlife
Service; and U.S. Geological Sur-vey, Biological Resources
Division.
Steering Committee Members: Perry Brown (Co-Chair), David
Parsons (Co-Chair), NormanChristensen, Rick Coleman, Chip
Dennerlein, DennisFenn, Denis Galvin, David Harmon, John
Hendee,Jeff Jarvis, Kenneth Kimball, Luna Leopold, RobertLewis,
David Lime, Nik Lopoukhine, JamesMacMahon, Michael Manfredo,
William Meadows,III, Chris Monz, Margaret Shannon, Jack WardThomas,
and Hank Tyler.
References__________________________Lucas, Robert C., comp.
1986. Proceedings, national
wilderness research conference: current research; 1985July
23-26; Fort Collins, CO. Gen. Tech. Rep. INT-212.Ogden, UT:
Intermountain Research Station. 553 p.
Lucas, Robert C., comp. 1987. Proceedings, nationalwilderness
research conference: issues, state-of-knowl-edge, future
directions; 1985 July 23-26; Fort Collins,CO. Gen. Tech. Rep.
INT-220. Ogden, UT: Intermoun-tain Research Station. 369 p.
—The Compilers
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v
ContentsPage
David N. Cole Wilderness Ecosystems, Threats, and Management
......................................1Stephen F. McCool
1. Overviews
.................................................................................................................................................3
James K. Agee Wilderness Fire Science: A State of Knowledge
Review ................................5
Yu-Fai Leung Recreation Impacts and Management in
Wilderness:Jeffrey L. Marion A State-of-Knowledge Review
.................................................................23
Mitchel P. McClaran Improving Livestock Management in Wilderness
..........................................49
John M. Randall Improving Management of Nonnative Invasive
Plants inWilderness and Other Natural Areas
.......................................................64
K. A. Tonnessen Protecting Wilderness Air Quality in the United
States ..................................74
2. Recreation Impacts and Management
..................................................................................................97
L. Alessa Effects of Soil Compaction on Root and Root Hair
Morphology:C. G. Earnhart Implications for Campsite Rehabilitation
..................................................99
Laurel Boyers Twenty-Eight Years of Wilderness Campsite
Monitoring inMark Fincher Yosemite National Park
.........................................................................105Jan
van Wagtendonk
Tracy A. Farrell Camping Impact Management at Isle Royale
National Park:Jeffrey L. Marion An Evaluation of Visitor Activity
Containment Policies
From the Perspective of Social Conditions
............................................110
Anna M. T. Gajda Managing Coastal Recreation Impacts and Visitor
ExperienceJudson Brown Using GIS
..............................................................................................115Grant
PeregoodoffPatrick Bartier
Ernest Hartley Thirty-Year Monitoring of Subalpine Meadow
VegetationFollowing a 1967 Trampling Experiment at Logan
Pass,Glacier National Park, Montana
.............................................................124
Mark C. Jewell Assessing Soil Erosion on Trails: A Comparison of
Techniques .................133William E. Hammitt
Paul R. Lachapelle Sanitation in Wilderness: Balancing Minimum
Tool Policiesand Wilderness Values
..........................................................................141
Yu-Fai Leung Wilderness Campsite Conditions Under an
UnregulatedJeffrey L. Marion Camping Policy: An Eastern Example
...................................................148
Christopher A. Monz The Consequences of Trampling Disturbance in
Two VegetationTami Pokorny Types at the Wyoming Nature
Conservancy’s Sweetwater RiverJerry Freilich Project Area
...........................................................................................153Sharon
KehoeDayna Ayers-Baumeister
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vi
P. E. Moore Meadow Response to Pack Stock Grazing in the
YosemiteD. N. Cole Wilderness: Integrating Research and Management
.............................160J. W. van WagtendonkM. P.
McClaranN. McDougald
Regina M. Rochefort Human Impact Surveys in Mount Rainier
National Park: Past,Darin D. Swinney Present and Future
................................................................................165
Akemi Yoda Erosion of Mountain Hiking Trail Over a Seven-year
Period inTeiji Watanabe Daisetsuzan National Park, Central
Hokkaido, Japan ...........................172
3. Wilderness Restoration
.......................................................................................................................179
David N. Cole Soil Amendments and Planting Techniques: Campsite
RestorationDavid R. Spildie in the Eagle Cap Wilderness, Oregon
....................................................181
Sean Eagan Restoration of Multiple-Rut Trails in the Tuolumne
Meadows ofPeter Newman Yosemite National Park
.........................................................................188Susan
FritzkeLouise Johnson
Joseph P. Flood The Influence of Wilderness Restoration Programs
on VisitorLeo H. McAvoy Experience and Visitor Opinions of Managers
.......................................193
David R. Spildie Effectiveness of a Confinement Strategy in
Reducing Pack StockDavid N. Cole Impacts at Campsites in the
Selway-Bitterroot Wilderness, Idaho .........199Sarah C. Walker
Charisse A. Sydoriak Would Ecological Landscape Restoration Make
the BandelierCraig D. Allen Wilderness More or Less of a
Wilderness?............................................209Brian F.
Jacobs
Catherine Zabinski Understanding the Factors That Limit
Restoration Success onDavid Cole a Recreation-Impacted Subalpine
Site ..................................................216
4. Wilderness Fire and Management
......................................................................................................223
Stephen F. Arno Mixed-Severity Fire Regimes in the Northern
Rocky Mountains:David J. Parsons Consequences of Fire Exclusion and
Options for the Future .................225Robert E. Keane
Anthony C. Caprio Returning Fire to the Mountains: Can We
Successfully RestoreDavid M. Graber the Ecological Role of
Pre-Euroamerican Fire Regimes to
the Sierra Nevada?
................................................................................233
Peter Z. Fulé Continuing Fire Regimes in Remote Forests of Grand
CanyonThomas A. Heinlein National Park
.........................................................................................242W.
Wallace CovingtonMargaret M. Moore
Thomas A. Heinlein Development of Ecological Restoration
Experiments in FireW. Wallace Covington Adapted Forests at Grand
Canyon National Park ..................................249Peter Z.
FuléMargaret M. MooreHiram B. Smith
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vii
Jon E. Keeley Restoring Natural Fire Regimes to the Sierra
Nevada in an Era ofNathan L. Stephenson Global Change
.......................................................................................255
MaryBeth Keifer Prescribed Fire as the Minimum Tool for
Wilderness Forest andNathan L. Stephenson Fire Regime Restoration:
A Case Study From the SierraJeff Manley Nevada, California
.................................................................................266
Kurt F. Kipfmueller Fire-Climate Interactions in the
Selway-Bitterroot Wilderness Area ............270Thomas W.
Swetnam
David J. Parsons The Challenge of Restoring Natural Fire to
Wilderness ..............................276
Matthew Rollins Twentieth-Century Fire Patterns in the
Selway-BitterrootTom Swetnam Wilderness Area, Idaho/Montana and the
Gila/Aldo LeopoldPenelope Morgan Wilderness Complex, New Mexico
........................................................283
G.Thomas Zimmerman The Federal Wildland Fire Policy:
Opportunities for WildernessDavid L. Bunnell Fire Management
...................................................................................288
5. Air, Water, and Exotic Species
............................................................................................................299
Paul Stephen Corn Fish Stocking in Protected Areas: Summary of a
Workshop .......................301Roland A. Knapp
L. Bruce Hill Visitor Perceptions and Valuation of Visibility in
the Great GulfWendy Harper Wilderness, New Hampshire
..................................................................304John
M. HalsteadThomas H. StevensIna PorrasKenneth D. Kimball
R. A. Knapp Effects of Nonnative Fishes on Wilderness Lake
Ecosystems inK. R. Matthews the Sierra Nevada and Recommendations
for Reducing Impacts .........312
Marilyn Marler A Survey of Exotic Plants in Federal Wilderness
Areas ..............................318
David S. Pilliod Evaluating Effects of Fish Stocking on
Amphibian PopulationsCharles R. Peterson in Wilderness Lakes
...............................................................................328
Ellen M. Porter Air Quality Management in U.S. Fish and Wildlife
ServiceWilderness Areas
...................................................................................336
6. Wilderness Management
.....................................................................................................................341
Shannon S. Meyer Legislative Interpretation as a Guiding Tool
for WildernessManagement
..........................................................................................343
S. Thomas Olliff Seeking a Scientific Approach to Backcountry
Management inSue Consolo Murphy Yellowstone National Park
.....................................................................348
Derek Petersen Grizzly Bears as a Filter for Human Use
Management inCanadian Rocky Mountain National Parks
.............................................354
Nicholas Sawyer The Development of the 1999 Management Plan for
theTasmanian Wilderness World Heritage Area (Australia)
........................362
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viii
Michael J. Tranel Wilderness Management Planning in an Alaskan
National Park:Last Chance to Do It Right?
...................................................................369
7. Dialogue Session Summary
................................................................................................................375
Peter B. Landres Naturalness and Wildness: The Dilemma and Irony
of ManagingMark W. Brunson Wilderness
.............................................................................................377Linda
MeriglianoCharisse SydoriakSteve Morton
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1. Overviews
2. Recreation Impactsand Management
3. Wilderness Restoration
4. Wilderness Fire andManagement
5. Air, Water, andExotic Species
6. Wilderness Management
7. Dialogue SessionSummary
-
USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 1
In: Cole, David N.; McCool, Stephen F.; Borrie, William T.;
O’Loughlin,Jennifer, comps. 2000. Wilderness science in a time of
change conference—Volume 5: Wilderness ecosystems, threats, and
management; 1999 May 23–27; Missoula, MT. Proceedings
RMRS-P-15-VOL-5. Ogden, UT: U.S. Depart-ment of Agriculture, Forest
Service, Rocky Mountain Research Station.
David N. Cole is Research Biologist, Aldo Leopold Wilderness
ResearchInstitute, Missoula, MT 59807 U.S.A., e-mail:
[email protected]. Stephen F.McCool is Professor, School of Forestry,
The University of Montana, Missoula,MT 59812 U.S.A., e-mail:
[email protected]
Wilderness Ecosystems, Threats, andManagementDavid N.
ColeStephen F. McCool
The Wilderness Act of 1964 gave wilderness managers adifficult
and challenging mandate. Wilderness areas are tobe kept in a wild
and natural state—relatively free of humaninfluence and human
control. Their value is dependent onthe degree to which they remain
unmodified—a contrast tothe highly modified world in which most of
us live. However,even the ecosystems in these most protected of
public landsare threatened by human activities both internal and
exter-nal to wilderness (Cole and Landres 1996). Impacts fromthese
activities vary in both intensity and areal extent.Recreation use,
often heavy and highly concentrated, hasturned many sites into
compacted, erosion-prone places,stripped of vegetation and topsoil.
Livestock grazing im-pacts, while absent in a majority of
wilderness areas, havebeen profound where they occur, with impacts
from currentgrazing practices often less pronounced than those of
thepast (Vankat and Major 1978). The impacts of fire suppres-sion,
while less intense, are widespread. Huge acreages ofwilderness have
already experienced profound changes invegetation structure as a
result of this activity. Air pollutioneffects may be even more
pervasive and problems with exoticinvasions are increasing all the
time.
As recognition of the prevalence and severity of humanimpact in
wilderness increases, pressure to restore wilder-ness ecosystems—to
compensate for human influence—mounts. Some managers are advocating
intentional ma-nipulation of wilderness ecosystems—from thinning
ofvegetation and management-ignited fire to liming of waterbodies
and genetic manipulation. This raises the seriousdilemma of whether
it is best to emphasize naturalness orwildness in
wilderness—whether to minimize human influ-ence or human control
(Cole 1996).
Science is needed to provide a foundation for
appropriatemanagement of wilderness ecosystems. Rich research
tradi-tions in the fields of wilderness recreation impact and
firehave contributed to relatively firm scientific bases for
deal-ing with these threats. Air quality programs, strengthenedby
the mandates of the Clean Air Act, are also relatively
welldeveloped. Most other threats to wilderness ecosystemshave
received even less attention. This problem is aggra-vated,
moreover, by the fact that many scientists who work
on large undisturbed ecosystems make little attempt toapply
their knowledge to wilderness management.
Managers need research on the nature and significance ofa wide
variety of anthropogenic impacts, as well as anunderstanding of
factors that influence impact characteris-tics. They need an
improved understanding of natural con-ditions and processes and the
extent to which existingconditions deviate from natural conditions.
They need prac-tical indicators and techniques for assessing
conditions andmonitoring deviation from natural or acceptable
conditions.Armed with this knowledge, managers should be in
animproved position when deciding where and what manage-ment is
appropriate.
This volume is devoted to research on human activitiesthat
threaten the integrity of wilderness ecosystems, im-pacts of those
activities, and management approaches thatminimize these impacts.
It is organized into seven sections.The first section provides five
overview papers, one on eachof five major threats. Yu-Fai Leung and
Jeff Marion providea comprehensive overview of the field of
recreation ecologyand update the synthesis of recreation impact
researchprovided in the proceedings of the first wilderness
scienceconference (Cole 1987). Jim Agee synthesizes the rich
re-search tradition on fire and its management in wilderness,again
updating a review developed for the first scienceconference
(Kilgore 1987). Research on air quality issuesand their management
in wilderness, another topic coveredin the first science conference
(Schreiber and Newman1987), is reviewed by Kathy Tonnessen. The
final two over-view papers provide research syntheses and
perspectives onthreats that were not addressed at the first science
confer-ence. Mitch McClaran examines livestock management
inwilderness, while John Randall covers management of
alienplants.
The second section consists of research papers on recre-ation
impacts and their management. While some of thesepapers improve our
understanding of the fundamental na-ture of recreation impacts,
many are devoted to assessmentand management of impacts. Papers in
the third sectiondeal with wilderness restoration. Most of these
papers areconcerned with restoration of sites damaged by
recreationuse. Papers on restoration of fire in wilderness are
in-cluded in the fourth section, along with other researchpapers on
fire regimes, impacts associated with suppres-sion of fires, and
appropriate fire management in wilder-ness. The few research papers
presented on air, water, andexotic species issues are collected in
the fifth section. Broadpapers on wilderness management and
planning are col-lected in the sixth section. The final section
consists of theone dialogue session included in this volume, a
sessiondevoted to the dilemma of manipulative restoration of
wil-derness ecosystems.
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2 USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000
References _____________________Cole, David N. 1987. Research on
soil and vegetation in wilderness:
a state-of-knowledge review. In: Lucas, Robert C., comp.
Pro-ceedings—National wilderness research conference: issues,
state-of-knowledge, future directions; 1985 July 23-26; Fort
Collins,CO. Gen. Tech. Rep. INT-220. Ogden, UT: U.S. Department
ofAgriculture, Forest Service, Intermountain Research
Station:135-177.
Cole, David N. 1996. Ecological manipulation in wilderness:
anemerging dilemma. International Journal of Wilderness. 2:
12-16.
Cole, David N.; Landres, Peter B. 1996. Threats to
wildernessecosystems: impacts and research needs. Ecological
Applications.6: 168-184.
Kilgore, Bruce M. 1987. The role of fire in wilderness: a
state-of-knowledge review. In: Lucas, Robert C., comp.
Proceedings—National wilderness research conference: issues,
state-of-knowl-edge, future directions; 1985 July 23-26; Fort
Collins, CO. Gen.Tech. Rep. INT-220. Ogden, UT: U.S. Department of
Agriculture,Forest Service, Intermountain Research Station:
70-103.
Schreiber, R. Kent; Newman, James R. 1987. Air quality in
wilder-ness: a state-of-knowledge review. In: Lucas, Robert C.,
comp.Proceedings—National wilderness research conference:
issues,state-of-knowledge, future directions; 1985 July 23-26;
FortCollins, CO. Gen. Tech. Rep. INT-220. Ogden, UT: U.S.
Depart-ment of Agriculture, Forest Service, Intermountain
ResearchStation: 104-134.
Vankat, John L.; Major, Jack. 1978. Vegetation changes in
SequoiaNational Park, California. Journal of Biogeography. 5:
377-402.
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1. Overviews
3
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USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 5
In: Cole, David N.; McCool, Stephen F.; Borrie, William T.;
O’Loughlin,Jennifer, comps. 2000. Wilderness science in a time of
change conference—Volume 5: Wilderness ecosystems, threats, and
management; 1999 May 23–27; Missoula, MT. Proceedings
RMRS-P-15-VOL-5. Ogden, UT: U.S. Depart-ment of Agriculture, Forest
Service, Rocky Mountain Research Station.
James K. Agee is Professor of Forest Ecology, College of Forest
Resources,University of Washington, P.O. Box 352100, Seattle, WA
98195-2100 U.S.A.
Wilderness Fire Science: A State-of-Knowledge ReviewJames K.
Agee
Abstract—Wilderness fire science has progressed since the
lastmajor review of the topic, but it was significantly affected by
thelarge fire events of 1988. Strides have been made in both
firebehavior and fire effects, and in the issues of scaling, yet
much of theprogress has not been specifically tied to wilderness
areas orfunding. Although the management of fire in wilderness has
beenslow to recover from the fires of 1988, science has progressed
mostsignificantly in its ability to deal with fire at a landscape
level. Majorchallenges include better understanding of the regional
context andfunction of wilderness areas, as well as understanding
and incorpo-rating fire patchiness, variability and synergistic
disturbance fac-tors into predictive models. If more precise models
are to be appliedaccurately in wilderness, better weather databases
are essential.
Wilderness fire has presented both managers and scien-tists with
considerable challenges over the 30 years thatwilderness fire
programs have been operational. Wildernessfire, in its purest form,
should be “wild” fire: unfettered bythe constraints of humans. We
have never prescribed a “let-it-blow” policy for tornadoes and
hurricanes, a “let-it-erupt”policy for volcanoes or a
“let-it-grind” policy for glaciers.Why, then, did we need a
“let-it-burn” policy for fires, orsurrogate strategies like
prescribed fire? Humans and firehave an inseparable history (Pyne
1995). We have been ableto control fire for human purposes for
thousands of years andfind it very difficult to “let wild fire
loose” (Pyne 1989). Thereare some good reasons for this reluctance,
including theissues of safety to humans and damage to resources
andproperty. As much as we have tried, we have not been ableto find
areas large enough to “let wild fire loose,” and this hasbeen at
the root of the challenges to research and manage-ment over three
decades. It remains a primary challengetoday.
The literature on fire in wildlands is immense. As inevery
field, some of it is hardly worth printing, while someis insightful
and informing. In this review, I cannot covereven the entire latter
category, and do not attempt acomplete literature review by any
means. My objective is tosummarize the major trends in wilderness
fire sciencesince its inception, with a focus on recent times, and
todefine scientific challenges for the future. Fortunately,there
are a number of major conference proceedings that
have synthesized fire research over the past decades andallow
somewhat cursory coverage in this review. In chrono-logical order,
they include: Fire Regimes and EcosystemProperties: Proceedings of
the Conference (Mooney andothers 1981); Proceedings – Symposium and
Workshop onWilderness Fire (Lotan and others 1985); National
Wilder-ness Research Conference: Issues, State-of-Knowledge,Future
Directions (Lucas 1986a) and National WildernessResearch
Conference: Current Research (Lucas 1986b);Fire and the
Environment: Ecological and Cultural Per-spectives (Nodvin and
Waldrop 1991); and Proceedings:Symposium on Fire in Wilderness and
Park Management(Brown and others 1995a). In addition, there is the
once-annual and now-periodic Tall Timbers Fire Ecology Con-ference
proceedings which contain significant materialrelated to wilderness
areas. Several books are availablethat provide specific geographic
or disciplinary informa-tion about fire: Fire and Ecosystems
(Kozlowski and Ahlgren1974); Fire Ecology of the United States and
SouthernCanada (Wright and Bailey 1982); and Fire Effects
onEcosystems (DeBano and others 1998). Some regional treat-ments
have been possible where information is abundant:Fire and
Vegetation Dynamics: Studies from the BorealForest (Johnson 1992);
and Fire Ecology of Pacific North-west Forests (Agee 1993).
Definitions of fires have changed over the past decades,most
recently in 1997. I have attempted to be faithful to thenew
terminology where possible, but doing so is awkward.The first
natural fires allowed to burn were called “let-burn”fires, but that
phrase conjured up an impression of nomanagement at all. It was
changed to “prescribed naturalfires” in the 1970s as part of a
tripartite division of fires:wildfires, which were unwanted fires
of any origin, pre-scribed fires, which were manager-ignited fires,
and pre-scribed natural fires. All of these fires were called
wildlandfires, as they occurred in wildlands, in contrast to
structuralfires. In the mid-1990s, Federal fire policy was
reviewed, anda new terminology was created. Prescribed fire
remained aseparate category, and all other fires were classed as
“wild-land fires,” which was somewhat confusing as that
phrasereferred previously to all fires in wildlands. The
wildlandfire category was subdivided into (1) wildfires
(unwantedwildland fires) and (2) wildland fires that might be
managed(those of natural origin burning within a predeterminedzone
and within prescription limits of some type): the oldprescribed
natural fire. Unfortunately, there has been noformal phrase adopted
for these fires: Prescribed naturalfire is now defined by what it
is not (not a prescribed orunwanted wildland fire). A logical name
such as “managedwildland fire” is not very descriptive or formally
used, so Iwill continue to call these fires “prescribed natural
fires,” or“pnf.”
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6 USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000
Historical Evolution of Fire ScienceApplied to Wilderness
___________
The recognition of ecological process as a major manage-ment
objective for parks and wilderness came of age in the1960s. Before
then, of course, there were national parks andmonuments managed by
the National Park Service (NPS)and designated wild areas and
primitive areas, as well asconsiderable unroaded but unclassified
lands, managed bythe Forest Service. Fire was suppressed in all of
these units,except for experimental burning in Everglades
NationalPark (Robertson 1962). Three major public policy
shiftsoccurred in one decade: the Leopold Report (1963),
theWilderness Act (1964) and Department of the Interior firepolicy
(1968) that recognized natural processes, includingfire, as valid
objectives of management. The Leopold Reportwas generated by a
wildlife controversy in YellowstoneNational Park, but its chair, A.
Starker Leopold, broadenedthe report to a grand vision of the
purposes of national parks(Leopold and others 1963).
The report recognized that the primitive landscapes ofAmerica
were, in large part, products of disturbance, includ-ing fire, and
that in the long run, management would only besuccessful if it was
to manage these disturbances, ratherthan just suppress them. The
authors were somewhat pes-simistic that this could ever occur, but
dreamed of recreatingthe “…vignette of primitive America...at least
on a localscale.” The report was very radical for its time and
wascirculated by the DOI for a year before Secretary of theInterior
Udall accepted it. That year, 1964, was the sameyear the Wilderness
Act passed and was signed into law byPresident Johnson. It defined
wilderness as an area “…un-trammeled [unaffected] by man,”
“…affected primarily bythe forces of nature...” and “…managed to
preserve itsnatural conditions.” The Leopold Report and the
WildernessAct provided similar guidance to scientists and
managers.Clearly, the natural force missing from almost every
parkand wilderness area was fire: How could it be reintroducedto
these systems? There was no regulatory guidance for anoperational
application of fire management until 1968, whenthe DOI released its
new fire policy, based on the concepts ofthe Leopold Report. This
new policy not only recognizedprescribed fire as a legitimate
action, but also sanctioned theuse of natural fires where
appropriate.
Within the same year, a fire management program wasinstituted at
Sequoia and Kings Canyon National Parks,accompanied by a research
program that investigated theeffect of these programs on fuels,
flora and fauna (Kilgoreand Briggs 1972). Yosemite National Park
followed in 1970.These parks had primarily low- and
moderate-severity fireregimes (c.f. Agee 1993), where fire
historically was fairlyfrequent and few of the fires were of
stand-replacementintensities over large areas (mixed-conifer/pine,
red fir).Higher-severity chaparral areas were avoided in the
initialyears. The broad granite terrain of these parks also
helpedcontain fires to individual valleys: Long wind-driven
intensefire runs were uncommon there. The early research there(Agee
1973; Biswell 1961, 1967; Hartesveldt 1964; Kilgore1971a,b, 1972,
1973; Parsons 1976, 1978; van Wagtendonk1972, 1974, 1978) clearly
showed that prescribed fire couldbe valuable in moving ecosystems
back to more naturalconditions, without unacceptable resource
damage, and that
prescribed natural fire could be successfully managed
(Kilgoreand Briggs 1972). Although Forest Service research hadbeen
helpful to the NPS scientists and managers, in bothresearch and
application the NPS was a leader by the early1970s (van Wagtendonk
1991a).
Yellowstone National Park began a prescribed naturalfire program
in 1972 (Romme and Despain 1989). Researchand monitoring there
found two seemingly apparent pat-terns: (1) Fires tended to burn
primarily in old-growth forest(Sweaney 1985) and naturally
extinguished themselves atthe boundary of younger forest; and (2)
very large fires werecharacteristic of the distant past (Romme
1982). Romme’swork was somewhat consistent with the monitoring, in
thathe found older forest to be more flammable than youngerforest.
But his reconstruction of the Yellowstone landscapesince the early
1700s suggested an ecosystem never inequilibrium or stability at
any park scale, due to large eventsat infrequent intervals. The
implications of these findingswere never addressed by the fire
management plan forYellowstone, although they were available almost
a decadebefore the fires of 1988.
The Forest Service began a similar wilderness fire pro-gram in
the Selway-Bitterroot Wilderness in northern Idahoin 1972. This
area contained forest types in moderate- andhigh-severity fire
regimes (Brown and others 1995b), andthe second fire that was
allowed to burn (Fritz Creek 1973)escaped, burning about 500 ha
outside of the managementunit (Daniels 1974). The fire had been
monitored during theburn, and research work was initiated after the
smoke hadcleared (Mutch 1974). The program was continued,
althoughit was later described by the agency as meeting with
“mod-erate” success (Towle 1985). In 1978 the Forest Serviceadopted
a nationwide “appropriate response” suppressionstrategy that more
clearly allowed this type of integratedfire management. A naturally
occurring ignition, under thispolicy, could be declared a wildfire,
but limited resourcesmight be directed to suppress it.
Manager-ignited prescribedfire was not allowed in designated Forest
Service wildernessthrough the mid-1980s.
The adoption of wilderness fire management plans
thatincorporated prescribed fire or prescribed natural fire
blos-somed in the 1980s. Associated with this increase
wereextensions of plans into primarily high-severity fire
regimesand the increase in both prescribed fire and
prescribednatural fire (Botti and Nichols 1995). Management
wasclearly moving faster than research, partly because of lim-ited
funding for park and wilderness research, and thelimitations of
science to address operational concerns.
Limitations of the Science Throughthe Mid-1980’s
__________________
The primary limitation posed by science for wildernessuntil the
fires of 1988 was the dissolving paradigm ofsuccessional theory.
The fading of a firm theoretical model(classical Clementsian climax
theory) to apply to distur-bance in natural ecosystems allowed
managers to viewreintroduction of fire as a “good” thing without
much atten-tion to either what fire was doing or where it might
go.Ecological problems with some fire programs were difficultto
solve because of a lack of records on where burns occurred
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USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 7
and a lack of monitoring of the fires’ effects on
resources(Thomas and Agee 1986).
The classical view of shifting paradigms (Kuhn 1970) wasthat
after an accepted model of science (a paradigm) wascreated,
evolving research would accumulate evidence sug-gesting the current
paradigm was too simple or just wrong.Eventually, a relatively
rapid shift towards a more robustmodel would occur, and that new
paradigm, in turn, wouldeventually be rejected in favor another,
more robust para-digm. In plant ecology, the major paradigms of the
centurythemselves underwent a succession similar to initial
floristics(Egler 1954; Agee 1993), where many of the species
(theo-ries) represented in the successional sequence are present
inearly succession but display differential dominance overtime. The
major plant ecology theories were all proposedwithin a decade early
in the 20th century, but exhibiteddifferential dominance over
time.
The classical view of plant succession (the theory thatattained
initial dominance) persisted much of the 20th cen-tury: the
Clementsian view of regional convergence towardsa vegetation
life-form created by autogenic succession in thepresence of stable
climate (Christensen 1988, 1991). Al-though competing models were
proposed early (Gleason 1917,Tansley 1924), the Clementsian model
was not seriouslychallenged until Odum (1969) proposed an ecosystem
modelthat had a number of tautological premises. Among themwere
assumptions that diversity and stability increased withecosystem
development (time since disturbance). Odum’spaper generated a
number of rebuttals (such as Drury andNisbet 1973) that suggested
that ecosystems did not haveemergent properties, that various forms
of diversity mightpeak in early succession and that stability might
in somecases be maintained by disturbance. Rather than producinga
more robust paradigm, these challenges to the existingorder
recognized that ecology is a science of place and time.Grand
unified theories are unlikely to apply (Christensen1988). Much of
the new theory was developed by ecologistswho had worked in
disturbance-prone ecosystems, and theyrecognized the multiple
pathways that succession might takeafter disturbance, a function of
both the disturbance and the“players” or organisms at the site.
Disturbance, rather than abinary presence-absence variable, became
a complex combi-nation of characteristics (White and Pickett
1985).
Wilderness fire scientists welcomed these challenges tothe
classical theory. The incorporation of disturbance intonew theory
provided a scientific niche for the presence offire in wilderness:
Disturbance had a place in naturallandscapes (White 1979). It was
now possible to moreclearly explain the previously baffling myriad
of succes-sional trajectories after disturbance. But as the
challengeswere comforting in one sense, they were discomforting
inanother. To what the new theory added in recognizing fireas a
natural factor, it removed in discarding the notion ofconvergence
toward stable ecosystem states (Christensen1991). This created two
managerial challenges: (1) Theissue of what to preserve became much
more complex, asecosystem classification resulted in much less
convergenceof community types; and (2) The stable end point
towardwhich we should manage suddenly disappeared, leavingmanagers
groping for a definition of a natural ecosystemstate or states.
This latter point had crucial significance forwilderness fire.
This question took form in 1980s wilderness as a debatebetween
structure and process as appropriate goals for parkand wilderness
management. In a somewhat simple synop-sis, the process argument
stated that every past landscapewas a snapshot of a variable
ecosystem, and that ecosystemwould vary into the future.
Reintroducing the process of firewould eventually restore an
uncertain but natural future setof ecosystem states (Parsons and
others 1986). This viewwas supported by some of the early
interpreters of theWilderness Act (Worf 1985a,b). The structure
argument(Bonnicksen and Stone 1982) stated that in any
ecosystemswhere an unnatural structure had developed,
reintroducingfire without attention to current structure could not
result ina restored natural ecosystem. To some extent, the
debatedepended on where one was (Agee and Huff 1986): after
all,ecology is a science of place. But the question remained
evenwhere scientists were viewing the same place. The
argumentbecame most heated in the Sierra Nevada/Cascades
low-severity fire regimes, where almost everyone agreed on
thedegree of ecological change but differed on the need
forstructural approaches to restoration (Bancroft and others1985;
Bonnicksen 1985).
Added to the uncertainty of a desired future condition wasthe
uncertainty of the disturbance regime. In the 1960s, therecognition
of fire as a natural factor was sufficient toencourage management
implementation. In the 1970s and1980s, more information began to
emerge about fire re-gimes. White and Pickett (1985) defined a
number of char-acteristics important for understanding the effects
of distur-bance (such as frequency, magnitude, seasonality,
extent,etc.), but for fire regimes, the primary one investigated
wasfrequency, and primarily for low-severity fire regimes.Kilgore’s
review of wilderness fire (1986) for the first confer-ence on
wilderness focused primarily on frequency withinbroad fire regime
types. More than 40 references to firefrequency were made by
generalized fire regime types. Thefire regime types did carry
implications for fire intensity, butlittle was known about extent,
season or synergism withother disturbances. Variability and
patchiness, now knownto be very important, were largely
unquantified. Someinformation on variability in fire frequency was
presented interms of ranges of fire frequency. Complex fire regimes
in themoderate severity fire regimes had little information
avail-able on patch size, proportions of different severity or
otheraspects of the fire regime.
Standards for monitoring were largely lacking during thisperiod.
Success was often gauged by area burned by pre-scribed fire and/or
prescribed natural fire. Even thoughuncertainty about the
operational goals of fire management(fuel reduction, ecological
effects, etc.) persisted, there waslittle information that could be
used to track progress to-wards any goal. Concerns about visual
effects of prescribedfire in giant sequoia groves led to
establishment of anindependent committee to review the fire program
at Se-quoia and Kings Canyon National Parks (Christensen andothers
1987; Cotton and McBride 1987). The committeerecommended
development of a detailed monitoring systemfor fires by the
National Park Service.
Stand-level dynamic models incorporating disturbance be-gan to
emerge in the 1970s, but they suffered from the absenceof
established subroutines for stand growth, fire effects, orfire
behavior. Most were derived from the JABOWA-type
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8 USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000
gap models that grew stands on a small area (Botkin andothers
1972). The first model, FYRCYCL, was developed atYosemite (van
Wagtendonk 1972) and was far ahead of itstime in using historical
fire weather to drive the fire portionof the model. Another early
model was SILVA (Kercher andAxelrod 1984), which was an improvement
on FYRCYCL inthe stand growth routine but less elegant in its fire
behaviorand fire weather. Fire effects on trees were estimated
fromscorch height (a function of fireline intensity) and
treediameter. However, many of the weather inputs were
heldconstant, so a crude simulation at best of the fire regime
waspossible. CLIMACS (Dale and Hemstrom 1984) was anotherfire model
parameterized for the Pacific Northwest. Itsstand growth
subroutines were robust but it treated distur-bance as an external
effect that required the user to defineexactly which size classes
and species were removed from aparticular disturbance. It was
verified for only one foresttype in the region.
Two models linking fire behavior and fire effects weredeveloped
during this period. Peterson and Ryan (1986)developed an algorithm
that integrated stand-level charac-ters and fire behavior
(including estimated flame residencetime) into a probability of
mortality that was a function ofvolume of crown kill and the
ability of a given bark thicknessto withstand lethal heat. The
model requires estimation ofburning time in order to compare time
of lethal heat tocritical time for cambial kill (based on bark
thickness), andburning time was not commonly available to users.
Ryanand Reinhardt (1988) used empirical data to develop asimilar
mortality function based on crown scorch volumeand bark
thickness.
One of the major developments useful in fire behavioranalysis
was adaptation of the Rothermel spread model(1972) to a variety of
stylized fuel models (Albini 1976),including those applicable to
wilderness. A PC-version knownas BEHAVE was made available in 1984
(Burgan andRothermel 1984), with later improvements in several
areas(Andrews 1986). This model allows prediction of surface
firebehavior for given fuel, weather and topographic predic-tions.
At high levels of input variables, fire behavior ex-pressed as
fireline intensity or flame length can be inter-preted as leading
to erratic fire behavior, but crown firemodels during this period
were limited to empirical studiesin boreal forests (Van Wagner
1977).
Most of the growth in operational fire management plansin the
1980s was in parks and wilderness areas withmoderate- to
high-severity fire regimes, suggesting thatthese plans contained
sufficient research information oneffects and behavior of fire to
indeed make these “pre-scribed” natural fire plans. In most cases,
this informationwas very generalized. Boundaries of prescribed
natural firezones were rather arbitrarily drawn inside the
boundariesof the preserves, with little attention to the main
directionof spread for intense fires or their historical or
projectedeventual size. Historical size could be estimated from
firehistory research, but technology to project fire behaviordays
or weeks in advance was not available. In other areas,such as the
chaparral of California, research in high-severity fire regimes did
occur but focused on ecologicaleffects of fire (Baker and others
1982; Parsons 1976; Rundeland Parsons 1979, 1980) and much less on
behavioralaspects. Limited research in the Pinnacles Wilderness
(Agee and others 1980) focused more on behavior thanecology.
Social science research was encouraged during this pe-riod,
focusing on visitor perceptions and acceptance of wil-derness fire.
Visitors who understood the role of fire inwilderness generally
supported the policies (Cortner andothers 1984; Rauw 1980; Stankey
1976; Taylor and Daniel1984; Taylor and Mutch 1986). The economics
of fire inwilderness remained clouded due to the blending of
firemanagement activities outside and inside wilderness whichmade
separation of costs difficult, and the different waysthat agencies
accounted for prescribed natural fire versuswildfire in the
pre-Yellowstone fires era. The Forest Serviceand some regions of
the National Park Service requiredupfront budgeting for monitoring
activities; when that bud-get was expended, the fire was reclassed
as a wildfire (Agee1985, Daniels 1991). Another complication is the
contrastbetween classical “least-cost-plus-loss” approaches,
whichassumes all resource change is a loss, and evaluation
ofresource change when fire could be viewed either as a cost
orbenefit. Mills (1985) defined the major obstacle to appropri-ate
economic analysis of fire in wilderness as understandingthe
“natural state” objective of wilderness which would thenallow
resource change to be viewed as cost or benefit.Ecologists, as
noted above, had been little help in agreeingon a consensus
definition useful for economic analysis.
The Wilderness Fire workshop held in Missoula in 1983(Brown and
others 1985) defined the major issues apparentat that time. Over
100 papers and posters were presented atthe conference, and five
major issues were addressed: (1) the“natural fire” issue—what is
natural; (2) the “Indian fire”issue; (3) the “lightning (prescribed
natural fire) versushuman (prescribed fire)” issue; (4) the “fire
size and inten-sity” issue; and (5) the “unnatural fuel buildup”
issue. Therewere no resolutions of these issues at that time, but
consid-erable discussion of each. Clearly, the issue of
“naturalness”was paramount in the first three topics. Are the
origins oreffects of fire the basis for “natural?” Native
Americansburned many of the landscapes of their day, often
repeat-edly, and these effects had a large influence on vegetation
asfar back as we can reconstruct it (Arno 1985; Gruell 1985;Kilgore
1985; Lewis 1985). How should this be incorporatedinto current fire
planning for wilderness? The lightningversus human ignition issue
is tied to the previous questionsand to the last question as well.
Arguments about how closea prescribed fire can mimic a natural
ignition (Despain1985), the need for caution in using prescribed
fire inwilderness (Daniels and Mason 1985), the need to focus
onfire effects (Van Wagner 1985) and the need to keep humanhands
off wilderness (Worf 1985a) all surfaced in this discus-sion. The
management-caused fuel buildup in some ecosys-tems was suggested to
be reason enough for prescribed fireprograms to restore more
natural conditions (Brown 1985;van Wagtendonk 1985).
Yellowstone: The Revolutionof 1988 ________________________
A revolution is defined as a drastic change of any kind, andthat
describes the events of the summer of 1988. Yellowstone’sfires were
at the center of the controversy because of their
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USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 9
visibility, but other fire events occurred that same yearunder
similar circumstances.
Yellowstone’s Fire ProgramYellowstone’s prescribed natural fire
program began in
1972 and was considered by the Park to be a successfulprogram
before 1988. An average of 30 fires per year burnedbetween 1972 and
1987 (Despain and Romme 1991), andabout half were monitored. The
monitoring of the firesduring this time indicated that fuels were a
major determi-nant of where fires burned, with weather influencing
thebehavior of the fires. Most fire starts and fire spread
oc-curred in older lodgepole pine (Pinus contorta) stands, andfires
appeared to naturally extinguish themselves at theedges of younger
stands. The monitoring results might havebeen interpreted to mean
that as more natural fires burned,the Park would be buffered from
extreme events by the patchmosaic of fuels (Sweaney 1985). However,
work by Romme(1982) had suggested that a very large event had
occurred inthe early 1700s over at least part of the Park.
The summer of 1988 brought many fires and little precipi-tation
compared to the 1972-1987 record, a very short periodof comparison
for a high-severity fire regime of hundreds ofyears. It is not
surprising that conditions of the extremeevent were not forecast,
and two-thirds of the 1972-1987period July and August precipitation
was well above long-term averages (Despain and Romme 1991). When
the firesof 1988 began to spread, they were pushed by a series of
coldfronts, which resulted in substantial increases in fire area
inshort periods of time, capped by the runs of early Septemberthat
resulted in fire area growth of tens of thousands of haper day.
By the end of the summer, over 300,000 ha (750,000 ac) ofthe
Park, and similar areas around it, had burned in aspectacular
series of fire runs. Roughly half of the areaburned was from direct
or indirect human causes (camper,firewood, power line), reviving
the argument of whethernature cared who started the fire (Van
Wagner 1985). Parkresearchers defended that area as “natural” by
claiming thatnatural fire starts in each area occurred later in the
sameyear and, under the extreme conditions of 1988, would
haveresulted in similar spread patterns (Despain and Romme1991).
Yet that argument remains a weak ex post factoattempt to justify
the argument that we were witnessing a“natural” event of
unparalleled magnitude in recent history.Certainly the scale had
precedent (Pyne 1982), but humanactivities altered the pattern and
extent of the fires of 1988(Christensen and others 1989).
Canyon CreekThe Canyon Creek fire burned in the Bob Marshall
Wil-
derness. Ignited by lightning on June 25, 1988, it wasdesignated
a prescribed natural fire and was allowed to burn(Daniels 1991). It
stayed at less than 1 ha (2.5 ac) for 26 days,but in late July grew
to 4,000 ha (10,000 ac) in three days,burning in a mosaic pattern
so that about a third of theencompassed area actually burned. After
65 days of activemanagement, the fire escaped the wilderness
boundary andgrew from about 25,000 ha (60,000+ ac) to almost
100,000 ha(250,000 ac) in 16 hours, at the same time the
Yellowstone
fires were rapidly expanding. Full suppression action wasordered
for the fire.
Prophecy FireThe Prophecy fire burned at Crater Lake National
Park,
Oregon, in August 1988. It began in the eastern boundaryarea of
the Park, but was within the approved natural firezone. Crater Lake
had managed natural fires for a decade inthe moderate-severity red
fir type, and these burns hadremained in prescription. The Prophecy
fire was pushed bystrong westerly winds and moved out of the Park
to coverabout 400 ha of Forest Service land to the east. These
windsmay not have been unusual, but the absence of weatherstations
in the area meant that this fire weather, and theassociated fire
behavior, would not be predicted. The firecrowned through a
sparsely vegetated climax lodgepole pinetype that was thought to
rarely support such behavior (Agee1981, Gara and others 1985).
Sifting Through the AshesBy late summer of 1988, the political
climate of an election
year, combined with the perceived multi-regional, multi-agency
failure of the natural fire program, resulted in thesuspension of
all such programs until completion of a reviewand implementation of
any review recommendations. Localpolicy reviews of the Yellowstone
situation (Christensen andothers 1989) and a major national fire
policy review (Philpotand Leonard 1989) were completed before the
end of theyear. The local review focused on ecological issues
andproposed both research and management recommendationsfor
Yellowstone. For research, the review recommended anecosystems
approach, a landscape or geographic context forindividual projects
and provision for long-term studies(Christensen and others 1989).
For management, the localreview recommended that an ecological
blueprint evolve ona wilderness-specific basis, to articulate
clearly the range oflandscape configurations locally acceptable and
to guide firemanagement planning. The national review (Philpot
andLeonard 1989) suggested that the natural fire policy was
ingeneral a sound policy, but that it had been implementedwithout
sufficient prescription criteria. Most of the plansthat did not
meet current policy were in national parks(Wakimoto 1989).
The Flame Flickers: Politics andPhilosophy After Yellowstone
_____
The political landscape has been as important as thenatural
landscape in directing wilderness fire science. Theevents of 1988
essentially shut out wilderness fire, and therecovery of management
programs over the past decade hasbeen relatively slow. No one
wanted to be the supervisor ofthe next Yellowstone event. Some
wildernesses, such asYosemite and Sequoia-Kings Canyon, which
pioneered bothprescribed fire and prescribed natural fire, had
their pro-grams reinstated almost immediately, as they met
thecriteria of the 1988 national fire policy review even
before1988. Other suspended programs have never been rein-stated.
The result was a significant and immediate decline
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10 USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000
in numbers of fires and area burned (fig. 1; Parsons andLandres
1998). Although area contained with prescribednatural fire zones
increased by seven percent between 1988-92, area burned by
prescribed natural fires decreased by 94percent (Botti and Nichols
1995), largely due to conservativemanagement criteria, including
funding. At the same time,prescribed fire activity doubled over its
pre-1988 levels(Botti and Nichols 1995), but this is largely due to
increasesfor one unit (Big Cypress National Preserve).
The conservative management criteria were all based oncontrol
(flame length) or external issues (smoke, availabilityof regional
forces). Not a single criterion was based onmeeting objectives for
wilderness management. Given thatplanning context, major reductions
in numbers of programsand fires allowed to burn are not at all
surprising. Yet theoperational management plans were not to blame.
Withoutan ecological blueprint for what was desired in
wilderness,it was not only much easier but more defensible to
defineconditions where fire was not wanted than to define
condi-tions where it was.
The consolidation of research scientists in the Depart-ment of
the Interior also affected wilderness fire science. Themanagement
agencies (such as the NPS) lost their ability tofund research,
because that function was now in the newlycreated National
Biological Survey. The brief life of both theNational Biological
Survey and its replacement, the Na-tional Biological Service,
resulted in financial chaos forresearch scientists, and funding for
fire research has contin-ued to be problematic in the Geological
Survey, where thesescientists now reside.
The political developments and problems of wildernessfire
management began to erode the “era” of wilderness fire(Pyne and
others 1996). Pyne correctly foresaw the 1990s asa new era of urban
intermix fires, and it was ushered in withthe horrific Oakland fire
of 1991 (Ewell 1995). Pyne’s decla-ration was rooted in the belief
that the philosophical ques-tions posed by the marriage of fire and
wilderness had neverbeen resolved and that technical approaches
could not re-solve them. Yet in the end, technical approaches must
beemployed to foster operational fire management programs,even if
the philosophical issues remain unresolved.
Science Since Yellowstone _______The science of wilderness fire
has progressed remarkably
in the past decade, withstanding the political issues and
alargely fragmented research approach. There have been fewlarge
research programs directed specifically toward wilder-ness fire,
partly because of the fragmented, multi-agencymanagement of
wilderness and a lack of research focus thatis characteristic of
many other large, national-scope projects(Long Term Ecological
Research, International BiologicalProgram, NASA’s space program,
etc.). The NPS GlobalChange program is one larger program that has
producedsome substantial implications for wilderness fire. Yet
manyof the technical developments have resulted from locallyfunded
projects, or from research done for other purposes.
Drivers of Wilderness FireThat fuel, weather and topography
drive the behavior of
an individual fire has long been known (Barrows 1951,Brown and
Davis 1973). Yet the factors driving wildernessfire regimes
continue to be debated: Are fuels or weathermore important? Our
research of the past decade suggeststhat the answer not only
differs by fire regime, but to someextent on the interaction of
fuels and weather. Swetnam andBetancourt (1990) linked a set of
regional cross-dated firehistories in ponderosa pine (Pinus
ponderosa) forests to high(La Nina) and low (El Nino) phases of the
Southern Oscilla-tion. During the El Nino phases, precipitation in
the South-west is much higher and fire activity is much less. At
thesame time, tropical and subtropical areas receive less
pre-cipitation as those storms are moving further north. Largeareas
burned in Borneo (Davis 1984) and Australia (Rawsonand others 1983)
during a large El Nino event in the early1980s. This link between
global climate and local variabilityin fire regime shows a trend
that links wilderness to the restof the world.
In high-severity fire regimes, arguments about the rela-tive
influence of fuels and weather continue (Weir andothers 1995,
Wierzchowski and others 1995). In Canadianboreal and subalpine
forests, prescribed fire has been usedoperationally under the
assumption that decades of fireexclusion have changed these forest
types, that youngerstands have not been created during that period
and thatolder forests were more flammable. Bessie and Johnson(1995)
concluded that weather was the primary drivingfactor in large fire
behavior; and since large fires constitutealmost all the area
burned, fuel conditions are relativelyunimportant. They generalized
these conclusions to all for-est types, a conclusion rebutted by
Agee (1997). He sug-gested that under extreme weather in
low-severity fireregimes, fire size may well have increased, but
that fireseverity may not have been markedly increased. Fuel
condi-tions have been shown to affect fire behavior and extent
inlow- (Wright 1996) and moderate-severity (van Wagtendonk1995)
fire regimes (fig. 2).
In some high-severity fire regimes, fire return intervalsmay be
so long that very unusual synergistic influences mayoccur and mask
more simple correlations of fire with flam-mability-stand age or
weather-climate patterns. In the Olym-pic Mountains, Henderson and
others (1989) mapped a verylarge forest fire event (fig. 3) circa
1700 A.D. that had been
Figure 1—Trends of numbers of fires and area burned since
theinception of prescribed natural fire programs in 1968. Note the
pro-nounced drop after 1988 (Parsons and Landres 1998).
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USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 11
Figure 2—A. Reconstructed fires of 1775-1778 in mixed-conifer
forests of eastern Washington (Wright 1996). Firesoccurring with
1-2 years of one another in this low-severity fire regime appear to
be extinguished when they enter recentlyburned areas. B. Monitored
fires 1974-1991 in Yosemite National Park show similar mosaics (van
Wagtendonk 1995).These appear to be more stable patterns than in
high-severity fire regimes where process overwhelms pattern under
severeweather (Romme and Turner 1991).
TeanawayButte
Swauk Prairie
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12 USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000
partially identified by Fonda and Bliss (1969). Fire cyclemodels
based on climate (Agee and Flewelling 1983) wereunable to reproduce
similar fire events, and it was thoughtthat very unusual patterns
of lightning frequency or foehnwinds may have occurred in the past.
Recently, a very largehistoric earthquake along the Washington
coast was recon-structed from tree ring records of trees buried
beneath sealevel by submergence of coastal lands at the time of
thequake (Yamaguchi and others 1997). This date was consis-tent
with records of a major tsunami that hit the east coastof Japan on
January 26, 1700. At a time when soils aresaturated, this
earthquake likely felled many stands of treesaround the peninsula,
and this additional dead fuel mayhave driven the large fire
activity that apparently occurred.Lightning frequency, drought or
foehn winds, the usualcombinations of factors associated with large
fires, may haveremained quite average during this period.
Where fire return intervals are quite long, these “surprises”may
be a major factor in the disturbance dynamics. Not onlymay extreme
events be driving the system, but they may beevents that we have
not yet uncovered. Lertzman and others(1998) showed through
simulating fire regime parameters thatsubstantial variability may
result, even in the absence of anunderlying physical or ecological
pattern. They recommendcaution in attributing causality of fire
regime drivers that arenot motivated by independently generated
hypotheses.
Fine-Tuning the Fire RegimeWhen early fire management programs
began in wilder-
ness, general knowledge of the fire regime was
consideredadequate. Research inside and out of wilderness has led
to a
more precise understanding of the fire regime, but it is
stillnot possible to generate many parameters of a fire regime
bysimply knowing, for example, what forest type is beingconsidered.
Where more precise information has been gener-ated, it usually
shows variability in frequency, intensity orextent. Synergistic
effects are known to be more importantthat previously considered,
although our ability to predictthem is still poor. And the general
implications for manage-ment have been clouded by the complexity of
these emergingfire regimes. Faced with considerable à·nges in
variability,which combination is appropriate for a certain place
now?Research on fire regimes has allowed us to place bounds
onuncertainty, but it has also generally driven us away fromrelying
on simple statistics like the mean. Programs haveevolved from
rather uniform burns to those incorporatingconsiderable variability
(Bancroft and others 1985; Parsonsand Nichols 1986).
Fire frequency has always been a primary parameter of thefire
regime. Kilgore’s wilderness fire review (1986) has over
40citations on fire frequency in selected wilderness ecosystems,and
he recognized that more examples could be cited. Butinformation on
other fire regime parameters was lacking.Since that time, we know
even more about fire frequency inwilderness. These new data have
allowed us to understandthe distribution of fire frequency, not
just its central tendency.A remarkable achievement was the
reconstruction of giantsequoia (Sequoidendron giganteum) fire
regimes back overmillennia (Swetnam 1993). The mean fire-return
intervalshifted significantly for this low-severity forest type
overperiods of centuries, and inferences about fire intensity
weremade from correlations of tree-ring growth with fire
occur-rences and percentages of sample trees scarred from
anindividual fire. Landscape juxtaposition of forest types wasfound
to be important in determining fire frequency. In thenorth
Cascades, where wet, west Cascades forest types aremixed with dry,
east Cascades types due to a rainshadoweffect west of the Cascade
crest, the wet types had fire-returnintervals well below those
measured elsewhere in the Cas-cades for those types. The dry,
eastside forest types had firereturn intervals well above those
measured in the easternCascades (Agee and others 1990).
Fire intensity remains difficult to reconstruct from his-toric
fire regimes. Reconstruction of growth on trees experi-encing fire,
and defining age classes of trees likely to estab-lish in
fire-generated gaps, have been used to infer historicintensities.
In giant sequoia groves where the history ofprescribed fire
includes some fairly hot burns, reconstruc-tion of tree-ring growth
showed that fire generally increasedgrowth, but some variable
response was evident (Mutch andSwetnam 1995). A delayed growth
response was foundwhere very intense fires had occurred and
scorched thefoliage of the sequoias. Sequoia regeneration was tied
to fire-generated gaps where sunlight could penetrate to the
forestfloor. These data were used infer past fire intensities.
Forexample, a fire in 1297 A.D. was inferred to be
relativelyintense due to the increase in tree growth on giant
sequoias(fig. 4), suggesting a release from competition and
substan-tial regeneration that occurred locally (Stephenson
andothers 1991). A recent article suggests that high-intensityfire
also was characteristic of ponderosa pine stands(Shinneman and
Baker 1997). However, these stands in theBlack Hills are
transitional to boreal forest; white spruce
Figure 3—The large fire of ca. 1700 in the Olympic
Mountains(Henderson and others 1989) appears to have occurred after
a largeearthquake in 1700. This quake, occurring in January, may
have beenassociated with considerable treefall and copious dead
fuel, needingonly an ignition source to become very large.
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USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 13
Synergism, or the interaction of fire with other distur-bances,
was recognized by White and Pickett (1985) as animportant parameter
of disturbance regimes. Very littlequantification of this effect
was evident for fire regimesbefore the late 1980s. Interaction with
insects has long beenrecognized as a major second-order fire effect
(Fischer 1980),but defining the degree of interaction is difficult,
as manyother factors are important (Amman and Ryan 1991). Afterthe
Yellowstone fires of 1988, the major tree species in thearea
(lodgepole pine, Douglas-fir [Pseudotsuga menziesii],Engelmann
spruce [Picea engelmannii], and subalpine fir[Abies lasiocarpa])
were attacked by a variety of insects;between 28-65% of the trees
living after the fire wereinfested and killed (Amman 1991). Most of
the bark beetle-attacked trees had basal damage from the 1988
fires.
At Crater Lake National Park, Swezy and Agee (1991)found that
low-intensity but long-duration fires, caused byforest floor
buildup due to fire exclusion, killed many of thefine roots after
late spring burns. Low vigor, old-growthpine trees had an increased
level of insect attack andmortality after these fires, and fall
burning was recom-mended as a better season, based on surveys of
trees burnedin spring and fall.
Disease can also be an important synergistic factor. Inthe
western United States, perhaps the most importantsynergism between
fire and disease is the introducedwhite pine blister rust (Kendall
and Arno 1990). Thisdisease causes cankers on the stems of young
pines andkills them. When fire kills older trees, recolonization
ofwhitebark pine (Pinus albicaulis), often mediated by
Clark’snutcrackers (Nucifraga columbiana) (Tomback 1982) maybe
short circuited. In mountainous terrain, snow ava-lanches can
create persistent snow avalanche paths andalter other processes
such as landsliding and future firespread (Butler and others
1991).
Models ________________________The past decade has witnessed an
explosion in personal
computing power and with that growth, an accompanyingexpansion
of models attempting to explain fire behavior andeffects. These
models have particular relevance to wilder-ness fire because they
allow forecast of spatially explicit firesizes, as well as fire
effects.
One of the more important models for fire effects has beenthe
individual tree model FOFEM (First Order Fire EffectsModel;
Reinhardt and others 1997). It scales mortality to thestand level
by aggregating individual tree effects to thestand level based on
the Ryan and Reinhardt (1988) mortal-ity algorithm. This model has
gone through four iterations inthe past decade and will continue to
be updated periodically.It is national in scope and provides
information in additionto tree mortality on fuel consumption,
mineral soil exposureand smoke. Synergistic effects, which tend to
be difficult topredict as second-order interactions, are not
predicted byFOFEM. Nevertheless, it has served as the basis for
treemortality prediction in several important models.
A variety of individual-based gap models have been devel-oped
since the 1970s (Hinckley and others 1996; Urban andothers 1991),
but few have concentrated on incorporatingfire. FIRESUM (Keane and
others 1989) was an improvedgap model that incorporated stand
growth and disturbance
Figure 4—Patterns of tree-ring growth from giant sequoias
(Stephensonand others 1991) show a pronounced growth effect after a
recon-structed fire of 1297 A.D. Unlike many previous fires, this
one must havebeen severe and reduced competition, as all trees show
a growthrelease. The pattern of unusual growth continues for a
century, andsome fires are associated with decreases in growth for
sample trees.This suggests severe fires did occur in sequoia
groves, and reminds usof the variability in fire regime for very
long-lived organisms like giantsequoias.
(Picea glauca) is a common understory species, and a com-plex
mix of fire regimes (e.g., Agee and others 1990) shouldbe expected
where types are in transition. Tree regenerationis closely linked
to fire severity; in moderate-severity fireregimes, severity will
have significant effects on tree specieslikely to establish
(Chappell and Agee 1996).
Quantifying season of burning has been important be-cause of the
opportunity to ignite prescribed fires over abroad seasonal range.
What is most natural? Historicalseasonality has been evaluated
primarily for low-severityfire regimes by defining the placement of
the fire scar for aparticular year in the earlywood to latewood of
the annualring. In Southwest ponderosa pine stands, most scars are
inthe earlywood, defining spring as the most common seasonfor fires
(Baisan and Swetnam 1990), although some areasexhibit more even
distribution of fires across the growthseason (Grissino-Mayer and
Swetnam 1995). In the PacificNorthwest, the same species exhibits
mostly late-seasonfires (Wright 1996). Heyerdahl (1997) showed that
there wasconsiderable seasonal variation in the Blue Mountains
ofOregon and Washington. Southerly Blue Mountain standshad a longer
snow-free season and more scars within thegrowing portion of the
annual ring than stands of the samespecies composition in the
northern Blue Mountains, whichhad a shorter growing season and a
concentration of scarsafter growth for the year had ceased.
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14 USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000
for inland Northwest conifers. The fire algorithms werecomplex,
but the stand-level results were greatly influencedby the
initializing stand condition; an individual tree dyingof old age,
for example, had a large influence on the basalarea output over the
simulation period.
While the science of gap modeling grew, the ability torepresent
wilderness landscapes in geographically refer-enced form also
increased. Geographic information systems(GIS) represented a way to
evaluate often inaccessible land-scapes in digital form. The
development of better softwarepackages and more powerful personal
computers allowedrobust analyses to occur at relatively low
expense. Fireapplications, such as analysis of historic fire
incidence byvegetation type, fuel inventories, prescribed burn
units,lightning strike incidence analysis and fire regime
analysis,were done (van Wagtendonk 1991b). Links of these types
ofanalyses to fire growth simulators were beginning (Bevinsand
Andrews 1989). Development of accurate input layersfor the current
generation of fire area growth models re-mains relatively poor
(Keane and others 1998).
FIRE-BGC (Keane and others 1996a) was developed bymarrying some
of the algorithms of FIRESUM with FOR-EST-BGC, a physiologically
based model (Running andGower 1991) that has been scaled up to a
landscape ap-proach. As applied to wilderness ecosystems in
GlacierNational Park (Keane and others 1996a) and the BobMarshall
Wilderness (Keane and others 1996b), the modellinks many
across-scale interactions, but it has the univer-sal problem of
marrying not only diverse spatial scales, butthose of time as well
(Keane and others 1996a). Temporalinformation at scales from annual
(stand growth equations)to hourly (fire growth equations)
complicate current model-ing efforts.
Disturbance propagation across landscapes has beenmodeled in two
general ways: percolation-type models anddeterministic models. The
percolation models suffer fromthe fact that fire does not move
across a landscape with equalprobabilities of spread in all
directions. The deterministicmodels suffer from data deficiencies
(Van Wagner 1987).Both have increased our knowledge of fire effects
and behav-ior at broader scales.
The percolation models have increased our knowledgeabout the
influence of landscape pattern on process (fire)(Turner 1989). Most
of the percolation work has been inhigh-severity fire regimes,
where the binary process of acell being occupied or not by
disturbance fits the high-severity nature of the disturbance. Work
in the 1980ssuggested that disturbance in heterogeneous
landscapeswas dependent on the structure of the landscape, as well
asdisturbance frequency and intensity (Turner and others1989). This
evolved to a more complex view that distur-bance probability
affecting percolation can change overtime, particularly where fire
weather becomes extreme(Turner and Romme 1994). Under extreme
conditions,process is relatively independent of pattern (Agee
1998;Romme and Despain 1989). Nonequilibrium systems willbe the
result (Baker 1989, Turner and Romme 1994);scientific advances in
landscape theory have resulted in atougher job for managers by
increasing the envelope ofuncertainty. Percolation-type models have
suggested thatlandscapes altered by past intervention in fire
regimes, orthose subject to climate change in the past (for
example,
Clark 1988) or the future, will take 0.5 to 2 rotations of
thenew disturbance regime for the landscape to adjust to thatnew
regime (Baker 1989, 1994).
In contrast to the ecological gap and disturbance models,fire
behavior models received less attention over the sameperiod, yet
our inability to predict fire spread and intensityhas had much more
effect on wilderness fire programs thanimprecision in predicting
ecological effects. Fortunately,substantial progress has been made
in landscape modelingof fire behavior. A nonspatial model (RERAP)
was developedto determine probabilities that a prescribed natural
firewould exceed an acceptable size (predetermined by the
user)before a fire ending event (precipitation) would halt
spread(Carlton and Wittala, no date). However, it has not
beenwidely used in wilderness fire management. A fire
growthsimulator (Bevins and Andrews 1989) was developed by
theForest Service, and a similar model was being developed bythe
National Park Service (Finney 1995). These effortsmerged in the
mid-1990s at the Missoula Fire SciencesLaboratory.
The model currently holding most promise for wildernessfire
behavior is FARSITE, a spatially and temporally ex-plicit fire
growth model (Finney 1998). The model wasinitially developed to
help predict spread of wilderness fires,but it has shown great
applicability to wildlands in general.The landscape “themes” or
data layers require informationon elevation, aspect, slope, fuel
model and canopy cover, withoptional themes for crown fire
behavior: crown height, crownbase height and crown bulk density.
Daily and hourlyweather streams are required over the simulation
period.Surface fire, spotting and crown fire behavior are
simulated,subject to the limitations of models that currently exist
forthose types of fire behavior. Fires spread in the model
usingHuygens’ principle, where the fire front is expanding basedon
elliptical wavelets, the shape of which depends on the fuelmodel
and local wind-slope vectors (fig. 5). Backing andflanking fire
spread is estimated from the forward rate ofspread, as the current
fire spread model (Rothermel 1972)only predicts the forward rate of
spread. Finney (1998)discusses the limitations of FARSITE.
Figure 5—The fire growth algorithm of FARSITE uses a series
ofellipses (Finney 1998). A. Under constant weather and fuels,
these“wavelets” are of constant shape and size. B. Non-uniform
conditionsshow the dependency of wavelet size on the local fuel
type but waveletshape and orientation on the local wind-slope
vector.
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USDA Forest Service Proceedings RMRS-P-15-VOL-5. 2000 15
Given accurate input data, the model is consistent
withexpectations for fire growth of surface fires. Spotting
andcrown fire spread are not possible to verify, although
simu-lations do produce patterns that resemble phenomena ob-served
on real fires. Outputs for FARSITE are geographi-cally referenced,
and flame length or fireline intensity percell can be exported to
fire effects and stand growth modelsto simulate landscapes over
time (for example, Keane andothers 1996 a,b). For wilderness
applications, FARSITEcould be applied to generate behavior under
worst-caseconditions to evaluate possible escape scenarios over
asummer for a prescribed natural fire, and could be linked
toecological effects. If adjacent fuelbreaks are proposed adja-cent
to wilderness as a rationale for loosening prescriptionsfor fire
within wilderness (Agee 1995), FARSITE can be usedto evaluate
effectiveness of the fuelbreak (van Wagtendonk1996) and spatial
effects on fire control efficiency (Finneyand others, in
press).
Few wilderness areas have databases that allow applica-tion of
FARSITE. Yosemite National Park was on-line earlydue to the
presence of an advanced geographic informationsystem (J. van
Wagtendonk, personal communication). WhereFARSITE data layers
(elevation, aspect, slope, fuel model,canopy cover, height to crown
base, crown bulk density andcanopy height) have been generated,
accuracy levels aresometimes so low (Keane and others 1998) that
applicationof the FARSITE model is bound to produce uncertain
re-sults, even if weather variables were perfectly predicted.
One of the major lessons learned in the 1988 fires wasthat the
Rothermel fire spread model was not particularlyrobust in
predicting the behavior of fires that contained alarge degree of
crown fire activity (Thomas 1989). Most ofthe quantification of
conditions where crown fire occurredwas derived from boreal forests
of Canada (Van Wagner1977). Crown fire assessments were possible
(Alexander1988) but not routinely employed by wilderness fire
man-agers. After the 1988 fire season, it was apparent thatbetter
understanding of crown fire behavior was needed.Rothermel (1991)
evaluated crown fire potential in north-ern Rocky Mountain forests,
and his derivation of crownfire spread was empirically derived as
3.34 times thesurface fire rate of spread of NFFL fuel model 10.
Links offorest structure (Agee 1996) and weather conditions
(Scottand Reinhardt, in press), using the Van Wagner
and/orRothermel approaches, have been made and are i