United StatesDepartment ofAgriculture

Forest Service

Volume 46, No.41986

FireManagementNotes

FireManagementNotesAn international quarterly periodical devoted to

forest fire management

Contents3 DESCON: A Proven Method of Reducing

Wildfire Suppression CostsDouglas J. Riley

4 Estimating Fuel Moisture in the Northeast: FuelSticks Versus the Tl-59

James L. Rudnicky and William A.Patterson III

7 Prescribed Burning of a Chained RedberryJuniper Community With a Helitorch

Guy R. McPherson, Robert A. Masters, andG. Allen Rasmussen

11 Efficient Fire ManagementJohn E. Roberts

13 Using the Fire Load Index as aClass-Day Indicator

Douglas J. Riley

15 Evaluating Structural Damage FromWildland Fires

Philip D. Gardner, Earl B. Anderson, andMay E. Huddleston

19 The Evolution of National Park ServiceFire Policy

David M. Graber

26 A Method to Assess Potential Fire SeasonSeverity

Mel Bennett

31 The USDA Forest Service Wildfire ProgramJames B. Davis

United StatesDepartment ofAgriculture

Forest Service

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Volume 46, No.41986

Fire Management NOles is published bythe Forest Service of the United StalesDepartment 0' AgricUlture, Washington,D.C. The Secretary of Agriculture hasdetermined that the publication 01 thisperiodical is necessary in the transac­tion of the public business required bylaw of this Department. Use 01 funds forprinting this periodical has been ap­proved by the Director of the outce ofManagement and BUdget HlroughSeptember 30, 1984.

Subscriptions may be obtained from theSuperintendent of Documents, U.SGovernment Printing Office.Washington, D.C. 2040'

NOTE-The use of trade, firm, or cor­poration names in this publication is forthe information and convenience of thereader, Such use does not constitute anofficial endorsement of any product orservice by the U.S. Department ofAgriculture.

Disclaimer: Individual authors are responsi­ble lor the technical accuracy of the materialpresented in Fire Management Notes

Send suggestions and articles to Chief,Forest Service (Attn: Fire ManagementNotes), P,O. Box 2417, U.S. Department01 Agriculture, Washington, DC 20013.

John A. BlOCK, SecretaryU.S. Department of Agriculture

A. Max Peterson, ChiefForest Service

L.A. Amtcarena. DirectorCooperative Fire Protection

Francis A. Russ,Generai Manager

34 Recent Fire Publications

2

Cover: The Butte Fire on the afternoon 01 August 29, 1985, 30 minutesbefore 73 persons were forced to deploy fire shelters. A forthcoming Issuewill contain detailed Information on this Incident, Including meterology, firebehavior, end shelter deployment.

Fire Management Notes

DESCON: A Proven Method ofReducing Wildfire Suppression Costs

Douglas J. Riley

Park Ranger, USDI National Park Service, DelawareWater Gap National Recreation Area, Buskill, Po.

Most, if not all, wildfire man­agement agencies are currently fac­ing the prospect of reducedbudgets, and are looking for waysto reduce wildfire managementcosts without adversely affectingeither the safety of fire manage­ment personnel or environmentalquality. One proven method ofreducing wildfire managementcosts that has been successfully uti­lized by a number of agencies isDESCON (Designated ControlledBurn).

DESCON refers to the processof controlling a wildfire throughthe use of existing barriers, (eitherconstructed roads, firebreaks,stone fencerows) or natural(streams, lakes, rock outcrop­pings). These barriers can be usedas they are, or they can becomeplaces from which to counterfire.The utilization of constructed ornatural barriers has several bene­fits:

I. Because the need to utilizeheavy equipment (such as dozers,tractors, or engines) in rugged ter­rain is reduced, repair costs areless, as are the costs of equipmentupkeep or rental.

2. Use of existing barriersgreatly reduces the need for hand­constructed firelines, thereby result­ing in reduced personnel costs.

3. Taking advantage of existingbarriers increases personnel safety,since the need for fire managementpersonnel to make a direct attackon a wildfire is greatly reduced.

Volume 46, Number 4

Counter/iring from within a constructed firetine.

DESCON has another big advan­tage in that planning can be doneahead of time for many wildlandareas. Fire maps can be made upwith known DESCON featuresmarked right on them for use inboth planning possible future firemanagement operations and con­tinuing ongoing fire managementoperations. Fire managementpersonnel who are going to beinvolved in either use of DESCONshould be well versed in both thefuels and topography that they willbe working with.

DESCON can also be very effec­tive when utilized in fire manage­ment operations involving fragileenvironmental areas, such as highalpine or tundra fires, where nor­mal fire management operationscan cause more environmentaldamage than the fire itself. In thistype of a situation, either throughadvance planning or on-the-sceneplanning, the fire is allowed toburn out when it reaches either aconstructed, or, more normally, anatural barrier that can either beused "as is" or improved throughcounterfiring.•

3

Estimating Fuel Moisture in theNortheast: Fuel Sticks Versus TI-59James L. Rudnicky and WilliamA. Patterson III

Research Assistant, Institute of Ecosystem Studies,The Mary Flagler Cary Arboretum, Millbrook, NY,and Associate Professor, Department ofForestry andWildlife Management, University of Massachusetts,Amherst, MA

Fuel moisture content is an impor­tant factor in the calculation ofseveral indexes that are part of theNational Fire Danger Rating Sys­tem (NFDRS) (2). The amount ofmoisture in a fuel particle and therate at which it dries are controlledby particle size (diameter) and byenvironmental parameters includ­ing temperature; relative humidity;wind speed; solar radiationreceived by the particle; and theamount) duration, and time sincelast precipitation. Before a particlecan burn, excess moisture must beevaporated to allow gases to be lib­erated and ignited.

The NFDRS uses fuel moistureto predict fire occurrence andbehavior. NFDRS indexes thatdepend upon fuel moisture includethe burning index (BI), which esti­mates the flame length of a spread­ing flame front; the ignitioncomponent (lC), which predicts theprobability of a firebrand ignitinga fire that will require suppressionaction; and the spread component(SC), which estimates the rate ofspread of a flame front. Fuel mois­ture sticks are commonly used tomeasure fuel moisture content. Thefuel sticks consist of four II2-inch­diameter wooden dowels that,together, weigh 100 grams Oven­dried. The fuel sticks are placedover a bed of conifer needles in anexposed area and weighed daily.The weight in excess of 100 gramscan be expressed directly as themoisture content of woody fuels

4

one-fourth to one-half of an inchin diameter (commonly referred toas la-hour timelag fuels).

In 1979, an algorithm was devel­oped so that the TI-59 hand-heldcalculator could be used to esti­mate fuel moisture content (l).The TI-59 uses daily weather obser­vations such as precipitation dura­tion, relative humidity, and airtemperature to estimate weight ofthe fuel sticks.

In 1982, the MassachusettsBureau of Fire Control (BFC)adopted the 1978 NFDRS as itsmethod for monitoring fireweather and predicting fire behav­ior and OCcurrence. Most fires inMassachusetts occur in early springafter the Snow has melted butbefore plant growth resumes(March, April, and early May). Itis during these months that fuelmoisture contents are typically attheir lowest levels. In 1983 theBFC fire-weather station atAmherst, MA, weighed fuel sticksand estimated values using a TI-59hand-held calculator. In this studyestimates of HI, IC, and SCobtained using fuelstick values arecontrasted with values obtainedusing the TI-59 estimates of fuelmoisture.

Methods

Fire weather data covering a 56­day period during the spring of1983 were used. Fuel moisture con­tent, HI, IC, and SC were calcu-

lated using data derived from fuelsticks and the TI-59 calculator.The average values based on fuel­stick and TI-59 estimates of fuelmoisture were compared using Stu­dents t-test, We used regressionanalysis to compare fuel stickweights and TI-59 estimates offuel moisture (3).

Results

Estimates of fuel moisture basedupon TI-59 calculations were con­sistently lower than those measuredby fuel sticks (figure I). On dayswhen it was raining when the fuelsticks were weighed, excess wateron the fuel sticks may have givenanomalously high values. Becausethe TI-59 algorithm does notreturn a fuel stick value larger than35 percent, we decided to eliminaterain days from the analysis. Differ­ences between values calculatedusing the TI-59 estimate of fuelmoisture and those obtained fromthe fuel sticks were highly signifi­cant (P less than .001) for MC, BI,and IC (table I). The fuel sticksconsistently gave higher values ondays following storms. Differencesbetween values derived using thetwo methods of estimating fuelmoisture gradually decreased in thedays following storms, suggestingthat the moisture content of thefuel sticks approached equilibriumwith the environment more slowlythan predicted by the TI-59 (table2).

Fire Management Not~s

Table I-Average values/or moisture content (MC), burning index (Bf), ignition component(IC), and spread component (SC) based upon measured and TI-59 estimates of lO-hr timelagfuel moisture {volues arefor days when it was not raining at the basic observation time (1300EST)/

Fuel stick and TI-59 moisturecontents were also compared byregression analysis (figure 2). Thecorrelation coefficient (r) indicatesa positive relationship between thetwo sets of values (as would beexpected), but the coefficient ofdetermination (r2

) indicates thatonly about half of the variation infuel stick data is explained by theTI-59. Thus, there is a wide rangeof actual fuel moisture values asso­ciated with each TI-59 estimate.The variability evident in figure 2indicates that in the Northeast itmay be difficult to derive an algo­rithm to relate fuel moisture toweather variables using hand-heldcalculators like the TI-59.

Differences in predicted fuel mois­ture influenced calculations ofburning indexes, ignition compo­nents, and spread components.Because the TI-59 "dried out" thefuel more rapidly than the fuelsticks actually dried, Bl's, IC's,and SC's rose more quickly and tohigher levels in the days followingprecipitation. Overall, the TI-59gave values for the Bl's and IC'sthat were significantly higher thanthose derived using fuel stick data(table I). For the SC, differencesbetween the two values were notsignificant.

5/19,I!

5/1

, I

tt

1983

tt

5

55

30

~ ~ 2.5[On; gc:'=- 0 I II

3/25 4/1

Figure I-Differences in moisture content values based on fuel sticks (.) and the TI-59 (*).Dates where the values coincide are indicated by an x. Solid vertical lines represent dayswhen the fuel sticks gave higher moisture values. Dotted lines are days when TI-59 valueswere higher. Arrows indicate days when it was raining at the time the sticks were weighed.Twenty-jour-hour precipitation amounts are shown on the lower graph.

ParameterMCBIICSC

Average based onFuel sticks TI 59

20 1026 3115 228.6 9.5

P value<.001<.001<.001

.06

DiscussionPredictions of NFDRS indexes

depend upon the accuracy of inputvalues used in the calculations.Fuel moisture content is one of the

Volume 46, Number 4 5

Table 2-A verage difference in moisture content (MC), burning index (BI), ignitioncomponent (IC), and spread component (SC) between fuel-stick and TI-59 values on daysfollowing precipitation

most important values used to esti­mate fire occurrence and behavior.If the fuel moisture values used forthe NFDRS do not represent fieldconditions, then the indexes cannotproperly rate fire danger.

Our analysis shows that theTl-59 does not reliably predict fuelmoisture content in central Massa­chusetts. Differences are greatestduring and following storms, whenthe Tl-59 can underestimate fuelmoisture by more than 30 percent.In the Northeast, spring storms areoften followed by periods of cooltemperatures and high humidity.Fuel sticks dry more slowly thanpredicted by the Tl-59, leading toanomalously high predictions forburning indexes and ignition com­ponents. Bureau of Fire Controlpersonnel often complained to usthat their estimates of fire danger,which were based upon Tl-59 cal­culations of fuel moisture, weretoo high. The Tl-59 often pre­dicted moderate to high fire dan­ger, for 2 to 3 days followingstorms, but BFC personnel knewfrom years of experience that theactual fire danger was low. Low

Figure 2-Fuel moisture values based upon the TI-59 plotted against those derived from thefuel sticks. The solid fine indicates the regression line. The analysis is based upon 46 pairs ofdata. We excluded from our analysis those days when it was raining.•

•

Literature Cited

1. Burgan, R. E. Fire danger/fire behaviorcomputations with the TexasInstruments TI-59 calculators: user'smanual. Gen. Tech. Rep. INT -61.Ogden, UT: U.S. Department of Agri­culture, Forest Service, IntermountainForest and Range Experiment Station;1979. 25 p.

2. Deeming, J. E.; Burgan, R. E.; Cohen,J. D. The national fire danger ratingsystem. Gen. Tech. Rep. INT -39.Ogden, UT: U.S. Department of Agri­culture, Forest Service, IntermountainForest and Range Experiment Station;1977. 63p.

3. Snedecor, G. W.; Cochran, W. G. Sta­tistical methods. 7th ed. Ames, IA: TheIowa State University Press; 1980. 507p.

•

SC-0.5-2.9-3.3

13.4

81 IC-3 -1

-12 -8-6 -7-2 -8-6 -4

Average difference

Fuel sticks55

191513

84

MC

fire occurrence on those daystended to support the beliefs ofBFC personnel. Eventually this dis­crepancy resulted in a lack of faithin the NFDRS on the part of BFCpersonnel.

We have recommended that BFCuse fuel sticks rather than theTl-59 to estimate fuel moisture inMassachusetts.

87776

Number ofobservations

a1234

Days sinceprecipitation

6 Fire Management Notes

Prescribed Burning of a ChainedRedberry Juniper Community With aHelitorch 1

Gny R. McPherson, Robert A.Masters, and G. Allen Rasmussen

Research assistants, Texas Tech University, College ofAgricultural Sciences, Department of Range andWildlife Management, Lubbock, TX.

Prescribed burning is an effec­tive means of reducing downedwoody debris in redberry juniper(Juniperus pinchotil)-mixed grasscommunities. Conventional groundignition techniques are effectiveand relatively inexpensive, but theyare limited to accessible areas.Large areas of rough terrain can­not be burned in a single day usingground ignition methods. Thispaper describes a prescribed fireconducted on a large area with ahelitorch,

The 4,Ol5-hectare (9,914-acre)unit is dominated by redberryjuniper-mixed grass habitat charac­teristic of the Texas rolling plains.It is located on the 7L division ofthe Triangle Ranch 40 kilometers(24 miles) northeast of Paducah,TX. (latitude 34° 10' N, longitude100°00' W).

The unit was chained 2 yearsprior to burning. Red needles werepresent on the chained juniper atthe time of burning. Fine fuel bedwas composed primarily of tobosa­grass (Hilaria mutica), little blue­stem (Schizachyrium scoparium),sideoats gramma (Boutelouacurtipendulai, vine mesquite

1 The authors wish to thank Henry A.Wright and Clifton M. Britton of TexasTech University, Jimmy Propst and GeneBradbury of Propst Helicopters. and ZachOsburn of Triangle Ranch. Many studentsand staff members from Texas Tech helpedon this burn. Their assistance is greatlyappreciated.

Volume 46, Number 4

(Panicum obtusum), buffalograss(Buchloe dactyloides), and three­awns iAristida spp.).

As a result of light grazing pres­sure (40 acres/animal unit/year),most grass plants were not grazed,leaving an abundance of rank mate­rial that reduced the palatability offorage. Chained woody debrisimpaired livestock handling anddecreasedforage availability andaccessibility. Furthermore, seed­lings and basal sprouts of redberryjuniper and honey mesquite(Prosopis glandulosa) were presenton the unit.

ObjectivesThe specific burn objectives were

to:• Remove 80 percent of downed

woody debris.• Reduce juniper canopy cover

by 70 percent.• Remove decadent material

from 70 percent of grass plants.• Check encroachment of juni­

per and mesquite by killing 70 per­cent of young plants.

The last two objectives would bemet if fire carried over 70 percentof the unit. Rank growth of herba­ceous plants is removed by burningand juniper, and mesquite trees arekilled if burned at a young age.Juniper trees can be killed if lessthan 15 years old (4), and honeymesquite can be killed if less than2.5 years old (7).

MethodsThe effectiveness of the burn in

removing downed woody debrisand reducing canopy cover wasmeasured along five 30-meter (98­foot) permanent transects ran­domly located in the unit. Inaddition, 20 temporary samplingplanes were established. Permanenttransects were marked with I-meter(3-foot) lengths of concrete rein­forcement bar numbered withmetal livestock ear tags. Downedwoody debris along transects wasinventoried using a planar-intercepttechnique (l). Canopy cover of allshrubs was estimated using lineintercept (2).

After burning, inventory ofwoody debris and canopy coverwas repeated on permanent tran­sects and on an additional 20 tem­porary transects. For each transect,percent consumption of woodydebris was calculated according toBrown (l). Reduction of canopycover-was determined by:

Percent reduction ~ (I ­

post burn cover) x 100 percentpreburn cover

To test the efficiency of perma­nent sampling, t-tests were con­ducted on all attributes measured.

Burning StrategyThe unit was prepared and

burned according to Wright andBailey (6). Two firelines weredozed 120 meters (400 feet) aparton the north and east sides of each

7

unit. Eighteen kilometers (II miles)of fire line were burned out withstrip headfires in January and Feb­ruary of 1985 under cool condi­tions (relative humidity 40 to 60percent, temperature 4 to 16 'C(40 to 60 'F), and windspeed 0 to16 kilometers per hour (0 to 10mi/hj). Main unit headfires were litwith a helitorch on 2 days, Febru­ary 25 and March 6, 1985.Weather conditions were measuredevery 30 minutes with a beltweather kit (5).

Aerial ignition was selected forsafety and time considerations.Steep, dissected terrain made handignition unsafe. Sheer drops of 20to 30 meters (65 to 100 feet) werecommon. Fine fuel load in drain­ages was about 10,000 kilogramsper hectare (9,000 Ib/acre). The

8

unit was dissected by numerousfuel discontinuities in the form ofroads, streams, and rocky ridges.A strip headfire ignition patternstarting in the northeast corner andmoving southwest into the windwas used to ignite the unit. Stripspacing was 100 to 150 meters (300to 450 ft). Consequently, an esti­mated 480 kilometers (300 mil ofstrip headfires were needed toburn the unit. Hand ignition wouldhave required at least 600 workhours, not including time for hold­ing crews. By contrast, 70 workhours were required for aerial igni­tion.

Ignition fuel was a mixture ofAlumagel and unleaded gasoline.The amount of Alumagel used var­ied according to air temperatureand relative humidity; cool and

'.

moist conditions required moreAlumagel. With an air temperatureof 21 'C (69 'F) and relative humid­ity of 34 percent, 5.6 kilograms(12.3 lb) of Alumagel were mixedwith 190 liters (50 gal) of gasoline.With an air temperature of 15 'C(59 'F) and relative humidity of 45percent, 6.0 kilograms (13.2 Ib) ofAlumagel were required to obtainthe desired consistency. The fuelmixture was applied at an averagespeed of 65 kilometers per hour(40 mi/h) from a height of 45 to60 meters (150 to 200 ft). The mix­ture was dropped in a 5-meter-wide(15 feet) strip, each drop the sizeof a golf ball.

Personnel and equipment werethe same both days. A burn boss,aerial ignition boss, 5-personhelipad crew, and two 6-personholding crews were used. The unitcould not be seen in its entiretyfrom a single observation point.Therefore, the aerial ignition bossdirected ignition from the helicop­ter. The burn boss, located on thebest possible ground observationpoint, directed the activities ofground personnel and coordinatedground-to-air communication. Tworadio frequencies were used-onefor the burn boss, helicopter, andhelipad boss and another for theburn boss and holding crews.

ResultsIgnition of the unit was com­

pleted in about 10 hours. The firstday, air temperature ranged from

Fire Management Notes

Table I-Downed woody fuel and canopy cover reduction resulting from a spring prescribedfire in the Texas rolling plains

TransectsPermanent 1 Temporary 2 Total 3

Standard Standard StandardAttribute Mean error 4 Mean error Mean error

Preburn woody fuel (m3/ha) 16.8 5.0 20.1 4.1 19.4 3.4Postburn woody fuel (m3/ha) 10.9 5.8 9.4 2.4 9.7 2.2Woody fuel reduction (%) 35.1 53.2 50.0Preburn canopy cover (%)

Downed woody debris 12.6 4.0 12.8 1.8 12.8 1.6Redberry juniper 15.1 3.0 13.0 1.3 13.4 1.2Other shrub species 2.7 1.7 3.1 0.8 3.0 .7Total 30.4 6.0 28.9 2.6 29.2 2.3

Postburn canopy cover (%)Downed woody debris 7.5 2.1 8.2 1.2 8.1 1.0Redberry juniper 6.0 2.5 6.2 1.6 6.2 1.3Other shrub species 2.3 1.5 2.2 .7 2.3 .6Total 15.8 3.9 16.7 2.2 16.5 1.9

Canopy coverreduction (%)Downed woody debris 40.4 35.9 36.7Redberryjuniper 60.2 52.3 53.7Other shrub species 14.8 29.0 23.3Total 48.0 42.2 43.5

1 n_ 5

2 n=20

3 n = 25 (combined results from all transects)

4 standard error of the mean calculated according to Steele and Torrie (1980)

17 to 21°C (63 to 69 OF), relativehumidity ranged from 30 to 40percent, and windspeed was 16kilometers per hour (10 mi/h).After a week of undesirableweather, burning was completedon a cooler day (temperature 12 to15°C (54 to 59 OF), relative humid­ity 40 to 50 percent, andwindspeed 13 kilometers per hour(8 mi/hj). Containment of the firewas not a problem, and nosuppression actions were required.Conditions for burning on March6 were cooler than normally pre­scribed for this fuel type. Earlyspring green-up, leading to a rap­idly increasing green component inthe fuel bed, forced ignition on arelatively cool day. As a result, thespecific burn objectives were notmet on the area burned March 6.

From transects flown after com­pletion of ignition, it wasdetermined that 61' percent of theunit burned. Concentration of live­stock on ridges and low-lying flatareas reduced continuous fine fuelbelow I,000 pounds per acre andcreated fuel breaks. By compari­son, drainages and hillsides werenot heavily grazed. As a result,only 20 to 30 percent of the areasof greatest livestock concentrationwere burned. However, dissectedterrain was characterized by 80 to90 percent fire coverage.

The accompanying table summa­rizes reduction in woody fuel vol­ume and canopy cover. Resultsfrom permanent and temporary

transects were similar for all attrib­utes measured. Downed woodyfuel and total canopy cover werereduced only 50 and 44 percentrespectively, primarily due to thediscontinuous nature of the fire.Where fine fuel was continuousenough to ensure fire spread,woody fuel volume was reduced 90percent, and total canopy coverwas reduced 85 percent. Moreover,consumption of 54 percent of livetree canopy reduced juniper stat­ure. In addition to improving visi­bility across the pasture, thisreduction in plant stature will

reduce the competitive ability ofjuniper, thereby increasing produc­tion of herbaceous species. Coolerthan normal conditions, coupledwith light fuel loads in some areasproduced less than desired resultson the second day of ignition.

Total cost of burning the unitwas $22,439.97, or $5.59 per hec­tare ($2.26/ac). The helitorch wascontracted for $2.47 per hectare($I.OO/ac). Remaining costs wereprimarily attributed to personnel($6,150) and transportation($3,996).

Volume 46, Number 4 9

Management ImplicationsNear optimal weather conditions

on February 25 compensated forfine fuel inadequacies, and burnobjectives were achieved. Becauseof cooler weather conditions andincreased percentage of green finefuel on March 6, overall objectiveswere not met. In light of this burn,we believe large units can beburned safely and quickly with ahelitorch at far less expense thanhand ignition. Because of thespeed of the operation. communi­cation is of fundamental impor­tance when using aerial ignition.Our experience indicates that tworadio frequencies are desirable tominimize confusion.

10

Permanent and temporary transectmeans were not significantly differ­ent (P <0.01) for any of theattributes measured. Therefore,these data indicate that fewer tran­sects can be used for samplingdowned woody debris and shrubcanopy cover in this fuel type iftransects are permanentlyestablished. Permanent samplingplanes can be established almost asquickly as temporary transects inthe field. The increased samplingefficiency offered by permanenttransects indicates that they are aviable alternative to temporary tran­sects in this fuel type. However, addi­tional research is needed beforepermanent transects can be univer­sally recommended.

Literature CitedI. Brown, J.K. Handbook for inventorying

downed woody material. Gen. Tech.Rep. INT-16. Ogden, UT: U.S. Depart­ment of Agriculture, Forest Service,Intermountain Forest and Range Experi­ment Station; 1974. 24 p.

2. Canfield, R.H. Application of the lineinterception method in sampling rangevegetation. Journal of Forestry.39: 388-394; 1941.

3. Steele. R.O.D.; Terrie, J.H. Principlesand procedures of statistics. 2nd ed.New York: McGraw-Hili; 1980.

4. Steuter, A.A.; Britton, C.M.Fire-induced mortality of redberry juni­per (Juniperus pinchotii Sudw.). Journalof Range Management. 36: 343-345;1983.

5. U.S. Department of Agriculture, ForestService. Belt weather kit. Fire ControlNotes. 20(4): 122-123; 1959.

6. Wright, H.A.; Bailey, A.W. Fire ecol­ogy. New York: John Wiley and Sons;1982.

7. Wright, H.A.; Bunting, S.C.;Neuenschwander, L.F. Effect of fire onhoney mesquite. Journal of Range Man­agement. 29: 467-471; 1976.•

Fire Management Notes

Efficient Fire Management

John E. Roberts

Fire Management Staff Officer, USDA Forest Service,Coronado National Forest, Tucson, AZ

Current Forest Service policy onwildland fire suppression is to sup­press wildfires at a minimum costconsistent with fire managementdirection and land and resourcemanagement objectives. Each wild­fire ignition requires an appropri­ate suppression response. TheForest Service defines an appropri­ate response as a "timely actionwith appropriate forces to safelyachieve fire suppressionobjectives. "

Now what does that mean? Itmeans we should select theresponse that meets the criteria ofthe policy and resource manage­ment objectives without wastingprecious dollars. According to theForest Service Manual, there arebasically three appropriateresponses to choose from­confine, contain, or control:

Confine-To limit fire spreadwithin a predetermined area princi­pally by the use of natural orpreconstructed barriers or environ­mental conditions. Suppressionaction may be minimal and limitedto surveillance under appropriateconditions.

Contain-To surround a fire,and any spot fires therefrom, withcontrol line, as needed, which canreasonably be expected to checkthe fire's spread under prevailingand predicted conditions.

Control-To complete controlline around a fire, any spot firestherefrom, and any interior islandsto be saved; to burn out any

Volume 46, Number 4

unburned area adjacent to the fireside of control line; and to cooldown all hot spots that are imme­diate threats to the control lineuntil the line can reasonably beexpected to hold under foreseeableconditions.

In the past, the Forest Servicehas tended to emphasize fire sup­pression. Therefore, the action thepublic is most familiar with is "con­trol." Also, the fires requiring thiskind of action are the ones mostlikely to get national presscoverage.

The action I want to talk abouthere is "confine." To implementthis action smartly requires consid­erable expertise, quick and decisiveplanning, and a degree of calcu­lated risk. One forest that hastaken the risk in full view of thepublic is the Coronado NationalForest, headquartered in Tucson,AZ. Although 1985 was not anexceptionally active fire season forthe Coronado Forest, it was atleast an average season, well abovethe national average as far as boththe number of fires and acresinvolved.

On 9,610 acres of wildland fireson the Coronado, the selectedresponse was to confine the fire.Now that in itself is quite an accom­plishment, particularly in light ofthe fact that more than 500 ofthose acres were four fires burningat the same time, in full view ofTucson and less than I mile aboveexpensive homes adjacent to the

Coronado boundary. Forest man­agers decided that the fire spreadwould be limited only by naturalbarriers and environmental condi­tions, and that surveillance wouldbe the appropriate action.

Now, consider taking that riskwith an entire metropolitan popu­lation watching to see if you didthe right thing. I don't intend tosay we had no problems, but itwas quite an accomplishment andan important step. To coordinatethe action and keep the publicinformed, to reassure worriedhomeowners, to keep emergency911 numbers unjammed, and soforth was not an easy task. Thedecision process itself is perhapsthe biggest stumbling block. Thatinitial decision is what starts it all.

The selected response to confinea fire could be made based on nat­ural barriers or environmental con­ditions. These two factors were theprimary basis for selection in thecase of the Coronado National For­est. If a fire is burning toward alarge rockpile and will then go out,the decision seems easy. But may­be it is not so easy. If you don'tgo all out, use engines, airtankers,and the like, and if the fire doesn'tgo out, what then?

I do feel that unfortunately thebudget is a major factor in decid­ing on the level of action. Themore you can do with less, itseems the more you lire asked todo, and the ones that waste moreget more to waste.

Confinement fires on theCoronado National Forest forJanuary-August 1985

The Coronado National Foresthas outlined some things over sev­eral years that have helped the man­ager on the ground make quickand sound decisions in difficult sit­uations. An analysis of pertinentfactors, similar to an economicanalysis, supports the decision toselect a particular suppressionresponse. Standard fire behavioritems such as intensity, fuel type,and fuel impostures, and the like,are coupled with resource values atrisk to determine the cost/benefitvalue of any action.

The Coronado National Foresthas been divided into basically twozones. Zone I has higher resourcevalues, and zone 2 has lower val­ues. Any risk to life and propertydemands the same aggressive sup­pression action in both zones. Inaddition to these two zones thereare eight wilderness areas thatreceive varying suppressionresponses. The initial decision isbased on the following:

• Where is the fire burning now?• Where is it expected to go?• What are the resource values

at risk?• Does the fire intensity level fit

in with the land management objec­tives for this area?

Basically, ask yourself, "Is-thefire creating unacceptable resourcedamage or is it expected to do sobefore natural barriers or environ­ment factors limit the spread?" Dis­trict fire management officers(FMO), with the help of fire behav-

ior calculations and several yearsof experience in local fire effects,can answer this question fairly rap­idly. Notice that I've emphasizedsome broad general descriptionsand no "magic numbers." That'sbecause there are no magic num­bers. If you rely on absolute for­mulas, you cease to think. On theCoronado National Forest, weknew from past experience that theparticular fires we were facing,under these conditions, were notgoing to create unacceptableresource damage.

You're probably sitting therethinking "that must take hours."But the initial decision by the dis­trict FMO took only minutes fromthe report of smoke and wasreviewed from the air by the forestFMO within the hour. The suppres­sion action, to confine, was quickand very sound. With proper plan­ning, both short and long range,these initial action decisions can bevery quick. All it requires is some­one willing to take the risk basedon the best information available.The employees of the CoronadoNational Forest are to be com­mended for their initiative.

Fire Rangername district

McDonald DouglasRedhill DouglasStanford DouglasSouth DouglasLeslie DouglasCastle SaffordEast Divide SaffordWindmill SaffordAsh SaffordVeach SaffordMontana NogalesHells Gate NogalesWilliams Sierra VistaPeak Sierra VistaSoldier Santa CatalinaEspero Santa CatalinaFinger Santa CatalinaPima Santa CatalinaCathedral Santa CatalinaTotal

Size(acres)

801500

7530020025

120800240

12143700

300300

104301251108010

9610

12 Fire Management Notes

Using the Fire Load Index as A Class­Day Indicator

Douglas J. Riley

Park Ranger, USDI National Park Service, DelwareWater Gap National Recreation Area, Buskill, PA

Table 2-FLJ versus percent oj fires occur­ring within given FLI limits

period. These data do not includeseveral large fires (in excess of 200acres) that have occurred becausesuch large fires are the exceptionrather than the rule. Data collectedprior to 1978 have not beenincluded because the NFDRS wasrevised in 1978. Fire weather dataprior to that date were based onthe old NFDRS system, which wasshown to be unsatisfactory.Table I-Number of fires occurring withinvarious ranges of FLI

Number of Number ofFLI fires FLI fires

0-2 21 51-53 53-5 4 54-56 06-8 3 57-59 29-11 4 60-62 0

12-14 4 63-65 015-17 3 66-68 018-20 8 69-71 021-23 2 72-74 224--26 10 75-77 027-29 12 78-80 030-32 19 81-83 033-35 19 84--86 036-38 14 87-89 039-41 23 90-92 042-44 12 93-95 045-47 4 96-98 048-50 14 99-100 0

IutroductionOne of the major pre-

suppression problems that wildfiremanagement personnel have todeal with is deciding the type andquantity of firefighting personneland equipment to bring on line inaccordance with the class-day indi­cator. Since the 1978 revision ofthe National Fire Danger RatingSystem (NFDRS), the fire loadindex (FLO has assumed a promi­nent role as a class-day indicator,in addition to the burning index(BI), and in many cases it will prob­ably replace the BI as the primaryclass-day indicator.

Index ComparisonThe burning index utilizes three

major factors or components as itsregulators: The l-hr timelag fuelmoisture (I-hr TL), the spreadcomponent, and the energy releasecomponent (ERC). Although thisparticular index provides a goodindicator as to the anticipated firebehavior (such as rate of spread,fireline intensity, and flamelength), it does not take into con­sideration the cause of the fires.However, fire cause plays a majorrole in determining how many firescan be expected on any given day.The number of fires expected on agiven day in turn plays a majorrole in determining the number ofpersonnel and the amount ofequipment needed to contain thefires that occur.

Volume 46, Number 4

The fire load index (FLI), whichis a rating of the maximum effortrequired to contain all probablefires occurring within a rating areaduring the rating period, is notbased only on the three major fac­tors or components that regulatethe BI. It is also the result of cal­culations that include the BI itself,the ignition component or IC (arating of the probability that a fire­brand will cause a fire requiringsuppression action), the lightningfire occurrence index or LOI (anumerical rating of the potentialoccurrence of lightning-causedfires), and the human-caused fireoccurrence index (an indication ofthe expected number of human­produced firebrands capable ofstarting fires that a rating area willbe exposed to during the ratingperiod).

Nevertheless, the BI, as well asthe other regulators that are usedto determine the FLI, should stillbe considered the primary indica­tors in determining the type of equip­ment needed and the distributionof fire suppression personnel.These indexes are still the primaryindicators of the type of fire behav­ior to be expected during the rele­vant rating period.

Fire Data Compilation andComparison

The following is a compilationand comparison of the fires thatoccurred within one National ParkService area during a 5-year

FLI

0-1718-2627-3839-4445-100

Firesoccurring

within indexlimits

3920643525

Firesoccurring

within indexlimits expressed

as percent of total

2111351914

13

1 Oata do not include any unusually large fires (morethan200 acres) tnet OCcurred.

Table 5-FLI vs average size of fire occur­ring within FLllimits I

Table 3-FLI versus percent of times FLIoccurred

Table 4-Percentage of times FLI occurredand percentage of fires occurring withinFL/ limits

Those not using any class-dayindicators might want to considerthe FLI. However. in order to effec­tively use either the HI or the FLIas a class-day indicator. it is neces­sary to have the following items:

I. At least 3-5 years of past fireweather records.

2. At least 3-5 years of past fireoccurrence records.

Personnel who do not maintaintheir own fire weather stations andrecords might be able to obtainsufficient correlatable data fromnearby State and National Parksand State and National Forests.•

FLI Class day Readiness class

0-17 Low I18-26 Moderate II27-38 High III39-44 Vary high IV45-100 Extreme V

Each readiness class calls for adifferent step-up action. with theintensity of the various step-actionsincreasing as the readiness classincreases. For example, in a readi­ness class I situation. the step-upaction might include a normal8-hour tour of duty. with a mini­mum of two initial attack person­nel per district. and a maximum offour initial attack personnel perdistrict. In a readiness class IV sit­uation. the step-up action mightconsist of the following directives:"All initial attack personnel on7-day workweek. with all tours ofduty to be extended from 0800 toat least 1800 hours. At least onebrush truck to be on patrol in eachsubdistrict at all times during theday shift."

ConclusionPersonnel currently using the HI

as the primary class-day indicatormight want to give the FLI a Sec­ond look. From all present indica­tions. the FLI seems to surpass theHI as a class-day indicator in termsof both accurateness and inclusive­ness.

Table 6-Comparison of FL/, class-dayrating system, and readiness class

235

109

2111351914

7413

832

Average sizeof fire (acres)

Firesoccurring withinFLI firrnte (0/0 of

total)

Times FLloccurred

expressed aspercent

of total FLIdays

7413832

0-100.25-15

0-600.1-130

0.25-45

1,1131911264229

Size range offires

within FLl

Times FLloccurred

Times FLloccurred (% oftotal FLI days)

FLI

0-1718-2627-3839-4445-100

FLI

0-1718-2627-3839-4445-100

FLI

0-1718-2627-3839-4445-100

14 Fire Management Notes

Evaluating Structural DamageFrom Wildland Fires 1

Philip D. Gardner, Earl B.Anderson, and May E. Huddleston

Assistant professor, Department of Soils andEnvironmental Sciences, University of California,Riverside; operations research analyst, PacificSouthwest Forest and Range Experiment Station,Riverside, CA; and technical publications editor(retired), Pacific Southwest Forest and RangeExperiment Station, Berkeley, CA.

Damage to structures as a resultof wildfires increases each year asurban development continues toencroach into wildlands. The needfor data on these losses increasescorrespondingly, as fire managersseek better information to use intheir fire management planning.However, information on wildfiredamage is often difficult to find.In the past, natural resource losseswere emphasized, and structuralfire suppression was not considereda basic Forest Service responsibil­ity. Thus, little attention was paidto the amount and value of struc­tural losses from wildfires.

To determine how the availabil­ity and utility of data on structurallosses might be improved, we exam­ined the literature and valuationreports from both public and pri­vate fire and insurance organiza­tions. Our analysis was limited tosouthern California, becauseefforts to locate data on otherpotential target areas for large struc­tural losses were unsuccessful inthe time available. Even in south-

I This article summarizes work accom­plished under a cooperative agreementbetween the University of California,Riverside. and the Pacific Southwest Forestand Range Experiment Station. The com­plete final report is on file at the PacificSouthwest Forest and Range ExperimentStation, 4955 Canyon Crest Drive, River­side. CA 92507: Frost, Grant; Gardner,Philip D. Validating estimates of structuraldamages resulting from wildland fires.Technical Completion Report; June 1982.

Volume 46, Number 4

ern California, available datasources were often incomplete. Fur­thermore, because various methodsare used to gather data, reportsfrom different agencies on thesame losses tend to be inconsistent.For a serious fire, assessor recordson property losses were comparedwith various other types of prop­erty loss information, includingdata gathered by an appraisalteam.

Results for the case studiedshowed that the loss estimated bythe appraisal team was higher thanthat obtained by other methods.The results also showed that prop­erty tax records could provide aconvenient source for structuralloss data. Several recommenda­tions are offered for the collectionand analysis of data on propertylosses due to wildfires.

Data Sources

We encountered major problemsin our search for data. Althoughwe identified a variety of datasources, reports were difficult toacquire. Some reports from pastfires could not be located, whereasmany from more recent fires wereincomplete. Names and dates didnot correspond among reportsfrom different agencies. Numbersof structures lost also differedamong agencies due to aggregationof related buildings, such as barnsand storage facilities.

To evaluate the sources of dataand their usefulness, we developeda method for rating major desir­able characteristics of the data(table I). Rated characteristicswere accessibility, extent of docu­mentation (based on fire damagelevel), reliability, verifiability, andinclusion of data on fire behavior.Three ratings were used: very use­ful, useful, and not useful. A use­ful rating implies that the dataobtained are helpful in certain spe­cific circumstances, but that thesource listed is not consistently sat­isfactory for each characteristic.Some data sources could not berated because the source did notinclude given categories.

Our review of data showed thatthe methods most often used toestimate the value of structures lostin wildfires were either appraisalby a team or individual or determi­nation of market value,replacement cost, or valuation bythe local·assessor. When values areadjusted for assessor practices,inflation, and local market condi­tions, they should not differnoticeably among sources.

Local tax rolls provided infor­mation on the value of propertyassessed at legally mandated inter­vals. One of the problems usuallyassociated with the tax assessmentis that it does not reflect currentmarket value (Lynn 1969). In Cali­fornia, this problem has been miti­gated by the adoption of a taxlimitation initiative (Proposition

15

VerifiabilityReliabilityData on

fire behaviorAccessibilitySource

Table I-Descriptive evaluation of data on structural losses from wildfires in southern California, by source I

Availability(based on number ofstructures per fire)

Federal:USDA Forest Service

State (California):Department of ForestryDepartment of InsuranceFire marshal

Local:AssessorFire departmentEngineer, building

departmentPrivate:

Board of realtorsInsurance companiesData collection

agencies

+

+++

oo+

+

,,=100 <100+

+ 0N/A N/A N/A0 0

+ 0 N/A+ 0+ N/A N/A

N/A NfA NfANfA N/A NfA0 N/A

0

0 +0 N/A0 0

+ +0 ++ +

? N/A0 N/A? N/A

1 +, very useful; 0, useful; _, not useful; N/A, not applicable; ?, unknown.

13), and the assessed value mustreflect the value of the structure atthe time of sale. Assessed valuecan be adjusted to current pricesby accounting for changes in localmarket prices and inflation fromthe base year (the year the prop­erty was last sold). Nonuniformitybetween taxing districts has alsobeen minimized under the initia­tive. In other States, however,careful attention must be given tohow the assessor appraises prop­erty and to possible nonconformityin practices across districts.

Case StudyTo find a method that could rea­

sonably provide the value of adamaged or destroyed structure,we obtained and analyzed data for

a case study, the Panorama fire. Itburned about 340 structures in ornear San Bernardino, CA, in Novem­ber of 1980. The Forest ServicePacific Southwest Region and theCalifornia Department of Forestryput together a professionalappraisal team to determine theextent of structural damage. Theappraisal team's report and prop­erty tax records from the countyassessor contained enough infor­mation to allow comparison ofseveral real property valuation meth­ods. As the buildings destroyedwere in a fairly homogeneous resi­dential area, we randomly selecteda IO-percent sample of all the resi­dences destroyed and estimatedthese five values: replacement cost,replacement cost less depreciation,

market value, property assessment,and appraisal estimate. Each esti­mated value was statistically ana­lyzed and compared with theothers.

Adequacy of the sample size wastested by increasing it by units of10 homes and calculating the dif­ference in the mean property val­ues (old versus new). The mean didnot change significantly after theaddition of 30 homes, which sug­gested that the IO-percent samplewas representative of the entirepopulation.

Total damage estimated for thesample by the five methods rangedfrom a high of $2.5 million to alow of $1.7 million. Average dif­ference per structure was about$25,000 between the high and low

16 Fire Management Notes

1 Numbers in parentheses are the approximate as-percent confidence intervals for the population correlationcoefficients.

Table 3-Sample correlation coefficients among real property values for 34 structures (10­

percent sample) destroyed in the Panorama fire I

Table 2-Total and mean damage values for 34 structures (lO-percent sample) destroyed inthe Panorama fire, near San Bernardino, CA, November 1980

ReplacementReal property Appraisal Property Market Replacement cost

value estimate assessment value cost less depreciation

Appraisal estimateProperty

assessment .42(.10, .66)

Market value .51 .75(21, .72) (.55, .87)

Replacement cost .41 .76 .95(.08, .66) (.57, .87) (.90, .97)

Replacement costlessdepreciation .43 .79 .94 .99

(.11, .67) (.62, .89) (.88, .97) (.98. 1.00)

$15,20012,8008,500

14,00013,300

Standarddeviation

$75.00059,00051,00073,00066,000

Mean damageper structure

ture. Therefore, firefighting agen­cies will need to establish acommon set of clear guidelines anddefinitions on how to account forand accurately report the addressof different types of structures,and will need to coordinate closelywith local assessors.

The degree of data precisionrequired for fire management pur­poses must be determined for eachsituation. Nevertheless, accuratenotes on some basic information

Totaldamage

$2.560.0002.000.0001.730.0002.500.0002.240,000

Appraisal estimateProperty assessmentMarket valueReplacement costReplacement cost

less depreciation

Reat propertyvalue

were inconsistent among agencies.In our judgment, the local asses­sor's rolls apparently could provideeasy access to value informationon structures damaged ordestroyed by fire in California.Adoption of this approach in otherStates may be more difficult.To obtain information on the typeof a structure and its value fromassessor records, the firefightingagency has only to reportaccurately the address of a struc-

RecommendationsEven though several data sources

were accessible, the informationthey contained could not be veri­fied. Data on the number andvalue of structures lost in a fire

estimates (table 2). Statistical exami­nation of data for individual par­cels showed that the' market valueestimates, although lower, corre­lated well with the two replacementcost values (table 3). The differ­ences might be explained partly bythe 2- to IO-month lag for theassessor to obtain sale prices andto make the necessary adjustmentsin market values. Market pricestend to lag behind, whereas replace­ment costs are updated regularlyby a computer program.

Property assessment was highlycorrelated with replacement costless depreciation, replacement cost,and market value. When assessedvalue figures were adjusted forannual housing price increases, theresultant values were comparableto replacement cost less deprecia­tion and fell between market valueand replacement cost figures (table2). The independent appraisal esti­mates were poorly correlated withthe others partly because the valuestended to be categorized in a fewlimited value classes, such as$100,000, $80,000, and $60,000.The average home value estimatedby the appraisal team was higherthan that estimated by othermethods.

Volume 46, Number 4 17

Structural damage from wildfires increases every year as more and more development takesplace in wild/and areas.

18

will undoubtedly be valuable onany fire report. Precise geographicinformation (parcel number orstreet address) should be recordedfor each structure. In addition togeographic location and fire char­acteristics, some information onstructural characteristics may bedesirable. Such variables as type ofstructure, quality, square footage,and improvements may be helpfulto adjust values taken from prop­erty assessment rolls.•

Literature CitedLynn, Arthur D., ed. The property taxand its administration. Madison,WI: University of Wisconsin Press;1969. 244 p.

Fire Management Notes

The Evolution of National ParkService Fire Policy 1

I

r David M. Graber

II}'I USDI National Park Service, Sequoia and Kings" Canyon National Parks, Three Rivers, CA

I

Service through the National ParksAct, and that legislation's vision­ary language directed the newagency "to conserve the sceneryand the natural historic objectsand the wildlife therein and to pro­vide for the enjoyment of the samein such manner and by such meansas will leave them unimpaired forthe enjoyment of future genera­tions." (fig. I).

r

U.S. Department of the Interior,National Park Service, the goalshave never been so clear cut.

The Yellowstone Act of 1872created a "public park or pleasur­ing ground for the benefit and enjoy­ment of the people" in which "thenatural curiosities or wonders"were to be maintained "in theirnatural condition." In 1916, Con­gress created the National Park

~~:A~(ztIih.4-~?,;;::~JFigure 1-The National Park Service was established for the protection ofnatural features and the pleasure of visitors. The role offire in park man­agement has evolved greatly since 1916.

I Reprinted from the Proceedings of theSymposium and Workshop on WildernessFire, Missoula, MT, November 15-18,1983.

A bstract: Fire policy dependsupon the function served by a unitof land and the land manager'sperception ofsociety's attitudestoward the role offire in nationalparks containing large naturalareas. This policy has evolved salta­torially over the III years sinceYellowstone National Park was cre­ated. Early policies emphasizedmanagement of the scene thatexisted when Europeans firstarrived. Present policy emphasizesmanagement for unimpeded natu­ral processes. Each stage in theevolution of society's attitudestoward forest land has altered andwill continue to alter NationalPark Service fire policy.

IntroductionChanges in the management of

fire in national forests have alwaysbeen closely affiliated with changesin the perceived function of thoseforests. Timber production, graz­ing, recreation, promotion of wild­life, and wilderness preservationare goals that elicit different firemanagement programs. Givenpresent-day knowledge of fire ecol­ogy and fire husbandry techniques,selecting the appropriate fire man­agement program is a relativelystraightforward process. For the

.1

\1

Volume 46, Number 4 19

Era of SpectaclesFrom 1886 to 1916, when the

U.S. Army administered thenational parks, and for the first 50years of National Park Servicemanagement, the mandate fromCongress was interpreted in a waythat excluded fire management(15). In fact, the early nationalparks were selected for their scen­ery and spectacles-geysers, water­falls, big trees, deep canyons.Protecting these phenomena andproviding opportunities for enjoy­ment of the scenery was ParkService policy, taken directly fromthe 1916 law. The policy was inter­preted to mean fire exclusion. Thatfire suppression in some areas cre­ates its own long-term threat tosafety and scenic resources was notyet appreciated.

During this initial period, thePark Service lacked the profes­sional cadre and sense of sharedvalues already well developed inthe USDA Forest Service (15). Inmost cases it was the ForestService that planned and con­ducted firefighting in the nationalparks. Park Service firefighting didnot come into its own until the1930's.

The management of nationalparks for protection of natural fea­tures and for the pleasure of visi­tors led to tourist accommodationsdirectly abutting those natural fea­tures and the creation of new amuse­ments such as bear-feeding stationsand the famous Yosemite firefall.

20

To protect living scenery, forestinsects and diseases were foughtwith pesticides and prophylacticcutting without regard to whetherthe phenomena were natural,exotic, or aggravated by humanpresence (9). Management of wild­life was largely an ad hoc affair.Although traditional Park Servicepolicy long has been "to permiteach species of wildlife to carryonits struggle for existence withoutartificial help" (9), individual super­intendents regularly ordered reduc­tions of hoofed animals when theywere believed to be overstocked ordamaging vegetation.

Thanks to work by scientistssuch as Adolph Murie and GeorgeWright, the policy of destroyingpredators to increase ungulates andreduce activities offensive to somevisitors was gradually abandonedin the 1930's (19). By the end ofthe decade, authors of internal docu­ments (4) and popular articles (5)were questioning the Park Servicehabit of feeding bears and thenkilling them when they became nui­sances. But despite valuable advicefrom people within and outside theagency, the Park Service lacked asubstantive resource policy. Fur­thermore' no professional scientistsand resource managers were avail­able to give life to such a policy.

Era of Resource MauagementNational park resource manage­

ment entered a new age in 1963when an advisory board on wildlife

management appointed by thenSecretary of the Interior StewartUdall filed its report entitled"Wildlife Management in theNational Parks" (11). TheLeopold Committee far exceededits formal directive and produced adocument that spoke to the broadissue of goals and policies for nat­ural resource management in thenational parks. Its words weretransformed into official policy:

As a primary goal, we wouldrecommend that the biotic asso­ciations within each park bemaintained, or where necessaryrecreated, as nearly as possiblein the condition that prevailedwhen the area was first visitedby the white man. A nationalpark should represent a vignetteof primitive America.With this goal clearly and for­

mally stated, the committee saidthat means to achieve it couldinclude reintroducing extirpatedspecies, controlling or eliminatingexotics, and managing populationwhere natural controls or park sizeand necessary habitat componentswere inadequate. Although timeand patience might restore climaxcommunities disrupted by fire, log­ging, or other disturbances, theloss of serial and other fire­dependent communities could onlybe restored by reintroducing fire.For the Sierra Nevada of Califor­nia, the report specifically recom­mended controlled burning as theonly method that could extensively

Fire Management Notes

•

'I•

tI'"\

I

I

"

iI'II

1I

reduce "a dog-hair thicket ofyoung pines, white fir, incensecedar, and mature brush-a directfunction of overprotection fromnatural ground fires."

The Leopold Committee restatedviews enunciated in 1962 at theFirst World Conference onNational Parks. There it had beensuggested that park managementserved a homeostatic function, sub­stituting artificial controls for nat­ural ecologic factors that had beenlost on account of inadequate parksize, extirpation, or cumulativehuman activities. The Leopold Com­mittee report stressed the manage­ment of a scene and defined thattarget scene explicitly as themoment when Europeans first laideyes on it: "A reasonable illusionof primitive America could berecreated, using the utmost inskill, judgment, and ecologicsensitivity. "

Possibly the most far-reachingrecommendation of the LeopoldCommittee was to develop a pro­fessional cadre of scientists andresource management specialistswithin the National Park Service:

Active management aimed atrestoration of natural commu­nities of plants and animalsdemands skills and knowledgenot now in existence. A greatlyexpanded research program,oriented to management needs,must be developed within theNational Park Service itself.Both research and the appli-

Volume 46, Number 4

The Park Service hadtwo distinct reasons forintroducing prescribedfire into its naturalareas.

cation of management methodsshould be in the hands of skilledpark personnel.The Leopold Committee report

provided a long-delayed rationalefor managing natural or wildernessareas in national parks. It calledfor acquiring scientific informationso that the "vignette of primitiveAmerica" could be determined andthe tools hest able to restore itselected. It repeatedly specified con­trolled burning as a preferred toolfor manipulating vegetationbecause of its low cost and its abil­ity to simulate the effects ofwildfire.

Those familiar with the writingsof John Muir know that his descrip­tions of open stands of conifers onthe western slopes of the SierraNevada and his reports of frequentfires set by local Indians (and atthat time ranchers as well) con­flicted sharply with conditions inYosemite and Sequoia NationalParks in the latter part of the 20thcentury. Reports by Hartesveldtand his coworkers (6, 7) found aclassic example of fire dependencein the giant sequoia (Sequoiaden­dron giganteum). The era of sup­pression apparently had drasticallyreduced reproduction while encour­aging undergrowth that jeopard­ized the famous giants when firedid-inevitably-recur.

Biswell (2) provided the techni­cal basis for fuel reduction by pre­scribed fire, and the National ParkService at last felt it had the policy

imperative, the biological justifica­tion, and the technical skills to intro­duce this management technique.As Pyne (15) reports, early suc­cesses in the Sierra Nevada embold­ened resource managers, and the1970's were years of enthusiasticexperiments with prescribed fires inseveral national parks. Unfortu­nately, in some of these experi­ments enthusiasm exceeded firemanagement techniques or a fullunderstanding of the ecologicalconsequences.

The Park Service had two dis­tinct reasons for introducing pre­scribed fire into its natural areas.The first was that nearly a centuryof fire suppression presumably hadaltered pristine plant communities,and living and dead fuels consti­tuted a threat of unnaturally hotand dangerous wildfire that imper­iled park resources, people, and sur­rounding lands. These threats andtheir reduction through prescribedfire rapidly became incorporatedinto management documents(17, 18).

Fires produced by natural igni­tion sources were permitted toburn with increasing frequency,but only insofar as they werewithin prescription and furtheredmanagement objectives. As naturalareas were modified by prescribedfire, managers felt that reducedfuel loadings would permit largerproportions of the parks to beincluded in natural fire zones.Both natural and prescribed fires,

21

Sequoia and Kings Canyon National Parks

o 5 Miies~

have made their first step torestore vegetation structure towhat it was in presettlement times,generally defined as approximatelya century ago. In most cases, that

Figure 2-Fire management zones for Sequoia and Kings Canyon NationalParks.

tains (1).Under the Leopold approach,

resource managers in a growingnumber of western parks with sig­nificant natural or wilderness areas

Fire Management Zone I(Alpine/Subalpine/Upper Mixed Conifer)Natural Fire Management Unit 1A

IZa Pre-1979 Natural Fire Mgmt. Zone[] 1979 Additions

o Conditional Fire Management Unit 18 hi·'!:"Yh'l'A~§f§~~~o Fire Management Zone II (J'.~'~~~~

(Sequoia-Mixed Conifer)• Fire Management Zone IIi

(Chaparral/Oak-Woodland)

however, were intended to servethe same end: restoring and per­petuating Leopold's vignette of"primitive America."

Evidence continues to accumu­late that, throughout much of theworld, aboriginal humans greatlyinfluenced vegetation by burning(15). This appears to be true ofCalifornia, including the SierraNevada (12). When Kilgore andTaylor (10) reconstructed the firehistory of sequoia-mixed coniferforest, they found a fire frequencysubstantially greater than one thatcould be generated by contempo­rary natural ignition rates, andconcluded that Indians were respon­sible for a large but undeterminedproportion of the fire scars theyfound. Partly because it is now dif­ficult to distinguish the historiceffects of aboriginal burning fromthose of lightning-caused ignitions,and partly because the LeopoldCommittee report specificallyreferred to "the condition that pre­vailed when the area was first vis­ited by the white man" (fromwhich one may infer that Indianswere to be included), managers inthe Sierra Nevada parks have beeninclined to merge both ignitionsources and their ecologic effectswhen calculating "natural" vegeta­tion patterns and developing pre­scribed burning plans. SimilarIndian burning effects have beennoted and similar managementconclusions drawn for other areas,such as the northern Rocky Moun-

22 Fire Management Notes

"

l~I

I,~

\1

structure has been estimated frompresent stand structure, fire scarsand other physical evidence, histor­ical records, and inferences drawnfrom similar vegetation elsewhere.All of these techniques-except inrare instances where actual reportsof Indian burning frequency andextent are available-lump ignitionsources for past fires. A combina­tion of mechanical manipulationand prescribed fire has then beenapplied.

Although not always explicitlystated, program objectives for the"first round" of burning programsgenerally include (I) restoring thepresettlement scene; (2) protectingvisitors, structures, featuredresources, and designated scenery;and (3) preventing, as an outcomeof ignition from any source, uncon­trolled wildfire that could burnareas within or outside park bound­aries in an unacceptable fashion.The rationale for this approach isfully developed by Parsons (14).

As techniques for burning havedeveloped to the point where first­round fire management programscan be implemented successfully,managers have been confrontedwith the dilemma of where to pro­ceed next. In natural areas, one isleft with the alternatives of ceasingprescribed burning and permittingnatural ignitions to provide thesole source of fire, or of supplement­ing/supplanting natural ignitionsindefinitely with prescribed fireswhose parameters would be deter-

Volume 46, Number 4

... parks are ecologicislands and cannot bemanaged as limitlesswilderness.

mined by available information onpresettlement fire behavior, presentand past vegetation structure, Orboth. In practice, the first alterna­tive is unlikely ever to be imple­mented strictly. Protection ofvarious resources and conflictingfire policies on adjoining lands willrequire prescribed fire for reasonsother than ecological objectives.The second alternative is obliga­tory if Indian burning was a signif­icant factor in creating thepresettlement scene.

Era of Ecological ReservesAs many wild ecosystems are

compromised by a variety ofhuman activities, such as mining,grazing, logging, and recreation,those that are left untouchedbecome increasingly valuable as liv­ing laboratories of natural ecologi­cal processes. Their value ascontrols in a world where humaninfluence is virtually omnipresentvaries inversely with the degree towhich they disturbed. This newlyemphasized function of naturalarea is explicitly recognized by thededication of International Bio­sphere Reserves under UNESCO'sMan and the Biosphere Program.American biosphere reservesinclude not only national parks butalso land managed by other agen­cies, and include both natural andmanipulated sites (16).

For the National Park Service,recognizing the scientific values ofnatural or wilderness areas intro-

duces some conflicts with otherapproaches. Human visitation,which is already acknowledged tocompromise wilderness value whenit reaches certain levels, may sig­nificantly compromise informationof scientific value by setting up sci­entific equipment, destructive sam­pling of resources, and other visualor acoustic blights on an otherwiseunmarred landscape. For theNational Park Service, these con­flicts remain unresolved at the pol­icy level.

The Leopold approach of scenemanagement is incompatible withmanagement for unimpeded natu­ral processes. By designating a par­tieular set of conditions as a"reasonable illusion of primitiveAmerica" and calling upon bothnatural and artificial processes toachieve it, new anthropogenic arti­facts-however subtle or artful­are introduced into the system andcompromise any study of naturalprocesses. An alternative approachrecognizes, as did the LeopoldCommittee, that parks are ecologicislands and cannot be managed aslimitless wilderness. This approachstill requires revising or mitigatinganthropogenic effects in naturalareas. But by abandoning thenotice of an end product-the "cor­reet" scene-natural processes arepermitted to proceed unimpairedwithin previously stated constraintsof protection of life, property, anddesignated resources. This new per­spective recognizes that ecosystem

23

processes and ecosystem elementsare interdependent and that bothare valid and important objects ofstudy.

The natural process approach towilderness management obviatessome difficulties with the Leopoldmodel and introduces a few of itsown. Cycles and trends in climate,erosion, and plant succession areno longer considered managementissues; they can be observed ratherthan confronted. Wildlife popula­tion phenomena such as epizootics,irruptions, and collapses are alsono longer at issue. What once wereproblems are now phenomena.Simulation of aboriginal burning isinappropriate because it freezes amoment in Indian cultural evolu­tion, climate, and biotic relationsfor all time. Had they been free tofollow their own cultural destiny,Indians presumably would nothave pursued deer, collectedacorns, and ignited fires inperpetuity.

Bonnicksen and Stone (3) eluci­date some of the inherent contra­dictions in what they call"structural maintenanceobjectives" and point out the inter­dependence of structure andprocess. They claim that in theSierra Nevada sequoia-mixed coni­fer forest, changes in forest struc­ture produced by decades of firesuppression have now sufficientlyaltered fire behavior so that fire/forest interactions with 0; withoutsimulated Indian burning do not

24

follow the pattern that would haveprevailed had Europeans neverentered the scene. Bonnicksen andStone focus on relatively short­term phenomena and ignore long­term variations produced byclimatic cycles that could far out­weigh human influence.

A serious difficulty in permittingunimpeded natural processes innational park natural areas is thatthere is little information on theanthropogenic factors that need .tobe corrected. Without data onlong-term lightning ignition andspread patterns, we cannot com­pensate for loss of fires that previ­ously invaded from beyond parkboundaries. When ungulate popu­lations explode and collapse, is itfrom loss of predators or habitatbeyond park boundaries or a natu­ral phenomenon? That kind of infor­mation can be obtained only byscientific study. The study of wild­fire pattern and process is itselfvalid, but repeated observation isneeded. National Park wildernesseshave fewer confounding variablesthan most other sites.

A greater difficulty in implement­ing a natural process approachmay be that high-intensity, exten­sive conflagrations are frightening,dangerous, and unpopular. Evolv­ing fire management techniquesmay eventually permit more fre­quent containment and less out­right suppression of chaparral firesand forest crown fires, but untilthen lower intensity, partial simula-

tions must suffice. In the manylocations where fuel buildup fromfire suppression would produce anunnaturally hot wildfire, prescribedfire remains the necessary firststep.

The ecological reserve approachto national park wilderness andnatural areas is compatible withthe Wilderness Act of 1964 and thephilosophy behind the act as devel­oped by Nash (13). The role of firein park wilderness is substantiallythat described by Heinselman (8).Although national parks have tra­ditionally emphasized the recrea­tional use of wilderness for itsesthetic and spiritual value, thatemphasis can be harmonious withpreserving the parks as reserves ofwild natural objects and processesfrom which we can learn moreabout the world and how we havechanged it and continue to changeit.

Literature Cited1. Barrett, Stephen W.; Arno, S.F. Indian

fires as an ecological influence in theNorthern Rockies. Journal of Forestry.80(10): 647-651; 1982.

2. Biswell, Harold H. Forest fire inperspective. Proceedings of the TallTimbers Fire Ecology Conference.7: 43-63; 1967.

3. Bonnicksen, Thomas M.; Stone, £'C.Managing vegetation within U.S.National Parks: a policy analysis. Envi­ronmental Management. 6(2): 101-102,109-122; 19&2.

4. Dixon, Joseph S. Special report on bearsituation at Giant Forest, SequoiaNational Park, California. Washington,

Fire Management Notes

t

,.,

DC: U.S. Department of the Interior,National Park Service; 1940. 5 p.

5. Finley, William L.; Finley, I. To feed ornot to feed ... that is the bearquestion. American Forestry. 46(3):344-347, 368, 383-384; 1940.

6. Hartesveldt, Richard J.; Harvey. H.T.The fire ecology of sequoiaregeneration. Proc. Tall Timbers FireEco!. ConL 7: 65-77; 1967.

7. Hartesveldt, Richard J.; Harvey. H.T.;Shellhammer, H.S.; Stecker. R.E. Thegiant sequoia of the Sierra Nevada.Pub!. No. 120. Washington, DC: U.S.Department of the Interior, NationalPark Service; 1975. 180 p.

8. Heinselman, Miron L. Fire in wildernessecosystems. In: Hendee, John C.;Stankey, George H.; Lucas, Robert c.,eds. Wilderness management. Misc.Pub!. 1365. Washington, DC: U.S.Department of Agriculture;1978; 249-278.

9. Ise, John. Our national park policy.Baltimore, MD: Johns Hopkins Press;1961. 701 p.

10. Kilgore, Bruce M.; Taylor, D. Fire his­tory of a sequoia-mixed conifer forest.Ecology. 60: 129-142; 1979.

Volume 46, Number 4

11. Leopold, Aldo S.; Cain, S.A.; Cottam,D.M.; Gabrielson, I.M.; Kimball, T.L.Wildlife management in the nationalparks. Trans. North Am. Wild!. Nat.Res. Conf. 28: 28-45; 1963.

12. Lewis, Harry T. Patterns of Indianburning in California; ecology andethnohistory. Ramona, CA; BallenaPress; 1973. 101 p.

13. Nash, Roderic. Historical roots of wil­derness management. In: Hendee, JohnC.; Stankey, George H.; Lucas, Robertc., eds. Wilderness management. Misc.Pub!. 1365. Washington, DC: U.S.Department of Agriculture; 1978; 27-40.

14. Parsons, David J. The role of fire man­agement in maintaining natural ecosys­tems. In: Mooney, H.A.; Bonnicksen,T.M.; Christensen, N.C.; Lotan, J.E.;Reiners, W.E., eds. Fire regimes andecosystem properties: Proceedings; 1978December II-IS; Honolulu, HI. Gen.Tech. Rep. WO-26. Washington,DC: U.S. Department of Agriculture,Forest Service; 1981: 469-488.

15. Pyne, Stephen J. Fire in America: a cul­tural history of wildland and rural fire.Princeton, NJ: Princeton UniversityPress; 1982. 654 p.

16. Risser, Paul G.; Cornelison, Kathy D.Man and the biosphere. Norman,OK: University of Oklahoma Press;1979. 109 p.

17.U.S. Department of the Interior,National Park Service. Fire managementplan. Three Rivers, CA: U.S. Depart­ment of the Interior, National ParkService, Sequoia and Kings CanyonNational Parks; 1979. 171 p.

18. Van Wagtendonk, Jan W. Refined burn­ing prescriptions for Yosemite NationalPark. Occas. Paper No.2. Washington,DC: U.S. Department of the Interior,National Park Service; 1974. 21 p.

19. Wright, George M.; Dixon, J .S.;Thompson, B.H. A preliminary surveyof faunal relations in national parks.Fauna Ser. No. I. Washington,DC: U.S. Department of the Interior,National Park Service; 1933. 157 p.•

New ToolsThe National Volunteer Fire

Council (NVFC) is offering a kitof public relations and fire preven­tion materials free of charge to anyfire department. The kit, called"New Tools for Volunteer FireFighters," includes advertisementsto help departments recruit, raisefunds, and promote fire safetythrough their local newspapers andmagazines, as well as a tape ofradio announcements recorded byrace car driver Richard Petty. Atelevision public service announce­ment on recruiting is also availablethrough the NVFC directors. Formore information, contact:

Gus Welter, NVFC Secretary9944 Harriett AvenueBloomington, MN 55420 •

25

A Method To Assess Potential FireSeason Severity

Mel Bennett

Forest Hydrologist, USDA Forest Service, OkanoganNational Forest, Okanogan, WA

r

Abstract: Long-term monthlyprecipitation data were used toestimate the chance for a severefire year. Monthly precipitationvalues were compared with pastsevere fire seasons to estimate thefuture occurrence of severe fireseasons. Fire season severity wassuccessfully predicted for fire sea­sons of 1983, 1984, and 1985 usingthis approach on the OkanoganNational Forest.

IntroductionA method to systematically eval­

uate the probability of fire seasonseverity prior to the central part ofthe fire season would assist manag­ers in preplanning deployment ofpeople and equipment. Tentativeassignment of fire personnel andequipment can be made to maxi­mize fire prevention and protectresources. Placing people andequipment for the most effectiveuse and benefit is important.

Different fire control strategiesare used in different areas of a for­est. These control strategies mayvary throughout the fire season.The fire season severity evaluationis an important part of the deci­sion tree that determines the actionto be taken in confinement andcontainment fire strategy areas.

BackgroundProbability concepts are used in

many hydrological and engineering

26

projects. One of the basic designsused is the frequency series, the list­ing of a range of values in order ofmagnitude (Lindsey and Franzini1964).

Fire management staff on theOkanogan National Forest have esti­mated potential fire season severityfrom precipitation values for cer­tain locations. When precipitationover a given period of time waslow I a severe fire season wasassumed to be ahead. High precipi­tation indicated a low likelihood offires.

Fire management needed a moresystematic approach to be able tobetter define the levels of "low"precipitation and what the proba­bility of a severe fire season was,by means of readily available pre­cipitation values.

Components of the MethodMonthly Precipitation-Low

monthly precipitation totals doindicate higher probability of asevere fire season. Monthly precip­itation values or combinations ofmonthly precipitation values weretotaled for each year for each sta­tion. This' can be any combinationof months which contribute to fireseason severity. Totals for eachyear of record were listed in orderfrom the lowest to the highest in afrequency series. Four stationswere tested for the general forestzone, Nespelem, Conconully,Winthrop, and Mazama. Informa­tion on precipitation values is

found in "Climatological Data"for Washington State, published inannual summaries by the NationalOceanic and AtmosphericAdministration.

Severe Fire Seasons-Thefrequency series of monthly precip­itation is compared to severe fireseason occurrence.

Deciding what constitutes"severe" fire seasons is importantto objectively determine the proba­bility of severe fire season occur­rence by precipitation totals. Thereare several methods for determin­ing or indexing fire season severity,but no common agreement on anymethod currently exists. Somesources for determining severe fireseasons include: (I) records oflarge acreages burned, (2) droughtrecords that indicated severe firepotential or occurrence, (3) per­sonal experience and/or knowledgeof someone else's personal experi­ence, (4) fire atlas records, (5) veg­etation growth records (tree ringsurveys), and (6) fire season sever­ity index of one's choice. The firstfour of these criteria were used toidentify the severe fire years forthe Okanogan National Forest.

Severe fire years used for thegeneral forest zone on theOkanogan National Forest were1910, 1919, 1926, 1928, 1929,1930, 1934, 1938, 1939, 1944,1945, 1961, 1962, 1967, 1970,1973, 1977, and 1979. Severe fireyears for the high elevation lands

Fire Management No.tes

,"

,,

were 1910, 1928, 1929, 1930, 1967,and 1970.

CorrelationTable I shows a comparison

between precipitation values andsevere fire years. Severe fire sea­sons tend to correlate with the low­est precipitation, although somefactors may have kept the lowestprecipitation years from beingsevere. For example, temperaturesmay have been below normal orwind movement was belownormal.

The correlation of severe fireseasons to total precipitation val­ues is expressed as percentage (col­umn 6, table 1). The percentage isthe probability of occurrence for asevere fire season with a given pre­cipitation range.

Using the percent probability asa management tool requires estimat­ing values that have the greatest

spread. 1n this example, maximumprobability is 60 percent (5 years).Whenever the current precipita­tion, in this example, was 1.27inches or less, there was a 60­percent chance of a severe fireyear. In the future this means ifthere is less than 1.27 inches ofprecipitation there is a 60-percentchance of a severe fire seasonoccurrence.

The next step is to calculate proba­bility of severe fire seasons forother precipitation totals. All rowsof table I with precipitation lessthan or equal to 1.27 are not con­sidered any further. The ranges ofprecipitation are determined sub­jectively and depend on precipi­tation totals or other factorsimportant to the user. The cut offused in table 2 is 3.00 inches ofprecipitation. Table 3 includesyears with 3.01 to 5.00 inches ofprecipitation. Table 4 lists the cor-

relation between severe fire seasonsand more than 5.01 inches ofprecipitation.

The probability of a critical fireseason developing is shown in table5 for given precipitation ranges.This table can be used in riskassessment.

The result is a probability tableof a severe fire season occurringwhich is based on past occurrence(table 5).

Table I-Comparison of precipitation (less than 1.28 inches) with severe fire season years

(1) (2) (3) (4) (5)Frequency series of

total precfp. Severefor Severe fire year

Total Precip selected fire year correlationsyears year period (in) correlation \IS. total years

, 1 1937 .75 No 0/1

r2 1973 .95 Yes 1/23 1960 1.20 No 1/3

I 4 1979 1.25 Yes 2/4.. 5 1967 1.27 Yes 3/5,i 6 1975 1.39 No 3/6,

7 1961 1.50 Yes 4/78 1957 1.79 No 4/89 1970 1.82 Yes 5/9

10 1964 1.83 No 5/10

(6)

Percentprobability

o503350605057505650

Volume 46, Number 4 27

I•Table 2-Comparison of precipitation (1.28-3.00 inches) with severe/ire season years

IJI~

Frequency seriestotal precip Severe

for Severe fire yearTotal Precip selected fire year correlations Percentyears year period (in) correlation VS. total years probability

1 1975 1.39 No2 1961 1.50 Ves (1)3 1957 1.79 No4 1970 1.82 Ves (2)5 1964 1.83 No6 1963 1.87 No7 1929 2.01 Ves (3)8 1930 2.07 Ves (4)9 1980 2.21 No

10 1934 2.31 Ves (5)11 1954 2.47 No12 1955 2.79 No13 1974 2.91 No14 1981 2.98 No 5/14 36

Table 3-Comparison of precipitation (3.01-5.00 inches) with severe/ire season years

Frequency seriestotal precip Severe

for Severe fire yearTotal Precip selected fire year correlations Percentyears year period (in) correlation VS. total years probability

1 1978 3.07 No2 1953 3.21 No3 1959 3.21 Ves (1)4 1935 3.27 No5 1945 3.47 Ves (2)8 1971 3.59 No7 1956 3.78 No ,I8 1949 3.81 No9 1969 3.94 No

10 1951 4.12 Ves (3)11 1950 4.37 No12 1972 4.94 No 3/12 25

Table 4-Compar:i:son of precipitation (more than 5.01 inches) with severe fire season years

Frequency seriestotal precip Severe

for Severe fire yearTotal Precip selected fire year correlations Percentyears year period (in) correlation vs. total years probability

1 1968 5.01 Ves (1)2 1947 5.27 No .f

3 1965 5.31 No4 1943 5.47 No5 1969 5.61 No6 1931 5.69 No7 1966 5.98 No8 1932 6.47 No9 1948 7.32 No

10 1946 7.33 No 1110 10

28 Fire Management Notes

"

Table 6-Probability ofsevere fire occurrence based on monthly precipitation

Table S-Probability of severe fire occur­rence based on monthly precipitation

AnalysisCombination of monthly precipi­

tation totals for stations on or nearthe Okanogan National Forestwere compared against the criticalfire seasons. The Nespelem stationprovided the closest correlationsbetween severe fire seasons andprecipitation on the OkanoganNational Forest.

Different combinations ofmonths allow tracking of precipita­tion totals through the beginningof the fire season so that severalcombinations of monthly precipita­tion can be analyzed (table 6).

29

average. There are factors notreflected in monthly precipitationvalues that influence fire severity;for example, high velocity winds,low humidity, and high incidenceof solar radiation. Heavy precipi­tation overcomes other contribut­ing factors of severe fire seasons.The probability is substantiallylower after some level ofprecipitation.

Precipitation values for Februaryand March on the OkanoganNational Forest usually provide lit­tle predictive capability. Precipita­tion falls on snow or wet heavyfuels, not substantially changingfuel conditions.

June and July precipitationincreases the probability estimatebecause precipitation in thesemonths influences fuel moistureduring the probable burningperiod. Precipitation values ofApril and May should be consid­ered as contributing some predic­tive capability and early-onassistance in fire planning.

Different monthly combinationsof precipitation were considered,some being more suitable than oth­ers. The months of August andSeptember were eliminated becausewhen monthly precipitation valueswere available, the peak fire sea­son was normally already wellestablished.

80713012603614

10075332275502910

Probability ofsevere fire year season (%)

This approach uses monthly pre­cipitation values because these val­ues are available for many years.However, the use of monthly pre­cipitation may be misleading.Some of the events creating asevere fire season are short termand may not be reflected inmonthly precipitation values. Forexample, monthly precipitation val­ues for May and June may behigh. These values do not show,however, when the precipitationoccurred. If the average precipita­tion for May and June fell the firstfew days of May and then was dryuntil the last few days of June,heavy fuels may have dried outsufficiently to create severe fireconditions, and the late June rainmay cause only a temporary wet­ting of the fine fuels, which coulddry out quickly. Severe fire situa­tions could exist even though pre­cipitation levels were near or above

Precipitation total(inches)

Less than .65Lessman.ao.65-1.93Greater than 1.94Less than 1.051.06-2.60Greater than 2.60Less than 1.091.10-1.301.31-2.45Greaterthan 2.46Lees than 1.751.75-2.802.81-4.28Greaterthan 4.28

60362510

Probability ofsevere fire season

(percent)

Volume 46, Number 4

Monthlycombination

March-April-May-June

March-April-May

March-April­May-June-July

March-April

Less than 1.271.28-3.003.01-5.00More than 5.01

Precipitation(inches)

I.

SummaryAccording to table I, when pre­

cipitation was below 1.25 inches,severe fire years occurred 60 per­cent of the time. The severe fireyears may occur in succession orbe separated by several years, butover the long term, 60 percent ofthe fire years will be severe if theprecipitation is less than 1.25inches.

The method described has beenused on the Okanogan NationalForest the past three fire seasons.

'Intermountain ResearchThe Intermountain Forest and

Range Experiment Station, head­quartered in Ogden, UT, is one ofeight regional experiment stationscharged with providing scientificknowledge to help resource manag­-ers meet human needs and protectforest and range ecosystems.

The Intermountain Stationincludes the States of Montana,Idaho, Utah, Nevada, and westernWyoming. About 231 million.acres, or 85 percent, of the land.area in the station territory is clas­.sified as forest and rangeland.These lands include grasslands,deserts, shrublands, alpine areas,and well-stocked forests. They sup­ply fiber for forest industries, min­erals for energy and industrialdevelopment, and water fordomestic and industrial consump-

30

In each of the past 3 years the fireseason severity was correctly pro­jected. The precipitation totals for1985 were used this year to helpmake midseason adjustments inconfinement and containment firestrategies. Precipitation levels fromthe analysis of past years were putinto the decision criteria to helpdetermine when confinement firestrategies would become contain­ment or control strategies.

This method allows fire manag­ers to systematically establish the

tion. They also provide recreationopportunities for millions of visi­tors each year.

Field programs and researchwork units of the station are main­tained in:

Boise, 1DBozeman, MT (in cooperation

with Montana StateUniversity)

Logan, UT (in cooperation withUtah State University)

Missoula, MT (in cooperationwith the University ofMontana)

Moscow, ID (in cooperationwith the Univeristy of Idaho)

Provo, UT (in cooperation withBrigham Young University)

Reno, NV (in cooperation withthe University of Nevada) •

probability of a severe fire seasonbased on past fire severity and pre­cipitation values. This informationcan help determine needs for pre­vention and suppression before thehot part of the fire season. Theinformation is also used to deter­mine control status of current orfuture fire control strategy.

Literature CitedLinsley. Ray K.; Franzini, Joseph B.Water resources engineering. NewYork: McGraw-Hill; 1964 (p. 110-132).•

Fire Management Notes

,,

,

The USDA Forest Service WildfireProgram

James B. Davis

Staff specialist, USDA Forest Service, Forest Fire andAtmospheric Sciences Research, Washington, DC

Figure I-Forest Service interregional fire crew.

,

i

"

For 80 years, the USDA ForestService has been the leader in theUnited States, and in most of theworld, in forest fire management.Three branches of the ForestService are involved with forestfire management activities.

The National Forest System,by far the largest of the threebranches, is responsible for fireprotection on almost 200 millionacres of national forests and grass­lands and on some adjacent andintermingled lands-an area that isabout twice the size of the State ofCalifornia.

State and Private Forestry(Cooperative Fire Protection)cooperates with State forestryagencies and private landownersengaged in forest fire activities.

Research staff members developand extend knowledge about fireprevention and management. Suchknowledge has helped solve manyof the critical fire problems thathave faced foresters for the pasthalf a century.

To control or manage fires onNational Forest System lands, theForest Service has built one of theworld's largest fire protection organ­izations, a group comprisingbetween 10,000 and 20,000 menand women, depending on the timeof year and the severity of the fireseason (fig. 1). This organizationengages in fire prevention, fuelmodification, fire detection, pre­suppression activities, and fire sup­pression.

Volume 46, Number 4

Before 1972, fire managementwas called fire control, and the pri­mary mission was to prevent orcontrol all forest fires. In 1971, theForest Service decided that merelyreacting to fires that had alreadystarted was not adequate and abroader approach was needed. Theconcept of greater preparednessinvolving increased presuppressionactivities began to receive new empha­sis. More recently, the ForestService further expanded fire man­agement to include the reintroduc­tion of fire to its natural role inselected forest ecosystems.

To achieve its goals, the ForestService uses prescribed fire, eitherby starting a fire or allowing awildfire to continue to burn undera carefully predetermined set ofweather, topographic, and fuelconditions (fig. 2). The objectives

of prescribed fire can be as variedas the forests of this Nation, rang­ing from reducing the flammabilityof chaparral in southern Californiato disposing of logging debris inthe Pacific Northwest to killingfungus pests in the Southeast.

The Role of the StatesPerhaps as important as the fire

management program on nationalforest land has been the ever increas­ing amount of non-Federal landbrought under fire protection.

The Cooperative Forest FireControl Program started under aprovision of the Weeks Act of1911. The law authorized the Sec­retary of Agriculture to enter intoagreements with the States "tocooperate in financing the organi­zation and maintenance of a sys­tem of fire protection on any

31

Figure 2-Prescribed burning is one of the fire management techniques cur­rently being used by the Forest Service.

private or State forest landson the watershed of a navigableriver." Under the law, cooperatingStates had to provide for a systemof fire protection to which the Fed­eral Government could contributeas much as one-half the cost.

The Clarke-McNary Act of 1924broadened and strengthened theprovisions of the Weeks Act. Sec­tion 2 of the Clarke-McNary Actauthorized extension of theCooperative Forest Fire ControlProgram to include all forest andcritical watershed lands in Stateand private ownerships.

These two laws prepared the wayfor steady progress in fire protec-

32

tion for the Nation's forested andnonforested watershed lands. In1917, only 21 States were cooperat­ing under the Weeks Act; by 1966,all 50 States were cooperatingunder the Clarke-McNary Act.

The Cooperative Forestry Assis­tance Act of 1978 superseded theClarke-McNary Act. This new actspeaks directly to recent programactivities that have emerged as partof the cooperative program withthe States, and it authorized thedevelopment of systems and meth­ods for improving programeffectiveness.

The Cooperative Forestry Assis­tance Act recognized that fire pro-

tection on State and private landsis a State responsibility. The newlydefined Federal role is to promotemore efficient State protection bytargeting Federal funds.

These aggressive programs, bothFederal and State, have been expen­sive. According to a conservativeestimate, the cost of fire protectionfor all wildland agencies rose fromabout $100 million annually in1965 to more than $600 million by1983. Forest firefighting emergencyfunds, which tripled between 1965and 1983, made up a significantpart of these costs.

Although the program has beenexpensive, it has also been effec­tive. The number of fires per mil­lion acres protected has declinedfrom more than 250 in 1917 toabout 100 in 1983. The reductionin acres burned is even more dra­matic, from 20,000 per millionacres protected in 1917 to slightlymore than 1,100 in 1983.

But these numbers representonly part of the success story.Although the area under protectionincreased eightfold between 1917and 1983, the total risk of firesstarting, as measured by varioustypes of land use, increased morethan tenfold. Considering theincrease in both the area protectedand the risk of fire, agencies couldhave expected more than 350,000fires in 1983. As a result of fireprevention efforts, however, onlyabout 100,000 actually occurred.

Fire Management Notes

I

I.r

Figure 3-0ne of many fire research tests conducted by the Forest Service.

Fire suppression efforts havealso been successful. The fires thatdo start are controlled at a smallersize. Statistics show that lossesfrom fire on protected areas mighthave exceeded 2.5 billion cubic feetof timber in 1981. However, with areduction both in the number offires and the average fire size, theloss of timber was less than 0.4 bil­lion cubic feet and has continuedto decline.

Because of the success in preven­tion and fire management, timbermortality by fire, on all protectedareas, has been superseded as thechief cause of loss of both sawtim­ber and growing stock. Fire hasfallen behind disease, insects, andweather as a major cause of timberloss.

The Role of ResearchAt the beginning of the 20th cen­

tury, foresters were responsible formanaging wild and remote areas inwhich the cause, behavior, andeffects of fire were poorly under­stood at best. Early fire researchwas essentially management sci­ence-trying to determine thewhat, the how much, and thewhere of a fledgling fire controlorganization and then attemptingto develop a policy for its use. Fireresearchers and forest managersfrequently traded roles.

Since World War II, however,the scope of fire research hasexpanded to include the physical,biological, and social sciences. Fire

Volume 46, Number 4

research today draws heavily onthe fields of meteorology, engineer­ing, public administration, andoperations research. In the 1960'sthe emphasis was on suppressioneffectiveness, with advances madein air attack and retardant devel­opment. In the 1970's, weatherresearch, fuels, fire effects, andprescribed burning were at theforefront. The knowledge, tools,methods, and strategies that firemanagers use nearly every dayhave evolved to a large extent fromfire research (fig. 3).

Despite such success, the state­ment "nothing succeeds like suc­cess" may not be true with respectto fire research. Whether fireresearch can continue to supplyknowledge on a timely basis is uncer-

tain; the budget for fire researchhas declined steadily since 198I.Furthermore, this reduction hasoccurred during a time when thecost of doing comprehensiveresearch increased substantially.

Perhaps even more important,forest fire research as a percentageof the total Forest Service researchbudget and as a percentage of theAviation and Fire Management sup­pression budget has declined sub­stantially since 1974. This meansthat fire researchers are now lessable to respond to user needs thanthey were a decade ago. Success infuture years will depend onresearch managers making verywise decisions about researchpriorities.•

33

Recent Fire Publications

Albini, Frank A. Wildland fires.American Scientist. 72: 590-597;1984.

Barnes, Will C. Trailing a firebug.American Forests. 91(8): 17,52-55; 1985.

Brown, J.K.; Marsden, M.A.;Ryan, K.C.; Reinhardt, E.D.Predicting duff and woody fuelconsumed by prescribed fire inthe northern Rocky Mountains.FSRP/INT-337. Ogden, UT:U.S. Department of Agriculture,Forest Service, IntermountainForest and Range ExperimentStation; 1985. 29 p.

Brown, Barbara G.; Murphy,Allan H. Quantification of uncer­tainty in operational and experi­mental fire-danger forecasts.Corvallis, OR: Oregon StateUniversity, Department ofAtmospheric Sciences; 1984.28 p.

Brown, Barbara G.; Murphy,Allan H. Verification of experi­mental probabilistic spot fire­weather forecasts. Corvallis,OR: Oregon State University,Department of AtmosphericSciences; 1984. 44 p.

Dieterich, John H.; Swetnam,Thomas W. Dendrochronologyof a fire-scarred ponderosa pine.Forest Science. 20(1): 87-96;1985.

Donoghue, Linda R; Main,William A. Some factors influenc­ing wildfire occurrence andmeasurement of fire preventioneffectiveness. Journal ofEnvironmental Management.30(1): 238-247; 1984.

Furman, R. William. Evaluatingthe adequacy of a fire-dangerrating network. Forest Science.30(4): 1045-1058.

Gabriel, Herman W.; Talbot,Stephen S. Glossary of land­scape and vegetation ecology forAlaska. Tech. Rep. 10.Anchorage, AK: U.S.Department of the Interior,Bureau of Land Management,Alaska State Office; 1984.137 p.

Gharabegian, A; Cosgrove, K.M.;Pehrson, J.R.; Trinh, T.D.Noise exposure quantificationanalysis for forest fire fighters.Irvine, CA: Fluor Engineers,Inc., Environmental ServicesDept.; 1984. 202 p.

Gonzalez-Caban A.; McKetta,C.W.; Mills, T.J. Cost of firesuppression forces based on cost­aggregation approach. Res. Pap.PSW-171. Berkeley, CA: U.S.Department of Agriculture,Forest Service, Pacific SouthwestForest and Range ExperimentStation; 1984. 22 p.

Huck, Chris. Burning the wilder­ness. American Forests.91(8): 13-16, 55; 1985.

Murphy, Allan H.; Brown,Barbara G. The state of the artof probabilistic weather forecast­ing. Corvallis, OR: OregonState University, Department ofAtmospheric Sciences; 1984.36 p.

National Wildfire CoordinatingGroup. Airtanker base planningguide. NWCG Pub. No. 440-1;NFES Pub. No. 1259. Boise,ID: Boise Interagency FireCenter, National WildfireCoordinating Group; 1984. 29 p.

Nicholas, N.S.; White, P.S. Effectof the southern pine beetle onfuel loading in yellow pineforests of Great Smoky MOlin­tains National Park.NPS/R/RM/SER-73.Gatlinburg, TN: USDI NationalPark Service, Uplands FieldResearch Lab; 1984. 40 p.

Radloff, D.L.; Freeman, D.R.;Yancik, R.F. FUELBEDEAST:User's guide for modelingactivity fuels and fire behaviorin eastern forests. Fort Collins,CO: U.S. Department of Agri­culture, Forest Service, RockyMountain Forest and RangeExperiment Station; 1984. 20 p.

Shute, Nancy. National Air andSpace Museum has a jump onforest fires for its new exhibit.Smithsonian. 15(12): 167-170;1985.•

34 -u. S. GOVERNMENT PR INTING OFF ICE: 19b6-490-912: 2ooo4-FS Fire Management Notes

United StatesDepartment of Agriculture

Washington, D.C.20250

OFFICIAL BUSINESSPenally for Private Use, $300

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