The Objective of thisPrescribed BurningG uide

To help resource managers plan andexecute prescribed burns in Southernforests by:

■ Explaining the reasons forprescribed burning.

■ Emphasizing the environmentaleffects.

■ Explaining the importance ofweather in prescribed burning.

■ Describing the various techniquesof prescribed burning.

■ Giving general information pertain-ing to prescribed burning.

A GUIDE FORPRESCRIBED FIRE

IN SOUTHERN FORESTS

Backing fire in young slash pine Postburn results

Rewritten in 1988 by Dale D. Wade,Southeastern Forest ExperimentStation; and James D. Lunsford, FireManagement, Southern Region,USDA Forest Service

Originally written in 1966 by Merlin J.Dixon, Southern Region, USDA ForestService.

1973-1979 revisions, lead author HughE. Mobley, Southern Region, USDAForest Service.

Photo assistance was provided by theAlabama Forestry Commission; GeorgiaForestry Commission; North CarolinaForest Service; USD1 Fish and WildlifeService, Piedmont National WildlifeRefuge; South Carolina Commission ofForestry; Southeastern Forest Experi-ment Station, Southern Region, andSouthern Forest Experiment Station,USDA Forest Service; Tall TimbersResearch Station; Union Camp Cor-poration; and Westvaco Corporation.

Appreciation is expressed to thevarious State and Federal agencies,private industries and other organiza-tions for their helpful reviews andcooperation.

This guide provides basic information needed to help you become technically proficient in the proper use ofprescribed fire. A glossary toward the end of this manual will help you with unfamiliar terms. To learn more aboutthe subject of prescribed fire, a list of suggested reading follows the glossary. Nearby State and Federal resourcemanagement agencies are also excellent sources of information. Many of these agencies provide periodic training in

fire behavior and prescribed fire.

Contents

ii

iii

Palmetto-gallberry fuel type prior to prescribed burn

Po stburn results

iv

introductionThe Ecology of Fire

Fire has played a major role indetermining the distribution of plantsacross the South. Some plant com-munities such as cypress swamps sur-vive for centuries between prolongeddroughts that finally allow stand-replacement fires to enter. Other com-munities such as the once vast expanseof longleaf pine burn every few years.In fact some ecosystems, for examplethe longleaf pine-wiregrass associa-tion, require periodic fire for theirvery survival.

A basic premise of fire ecology isthat wildland fire is neither innatelydestructive nor constructive: it simplycauses change. Whether these changesare viewed as desirable or not dependsupon their compatibility with one's ob-jectives. Irrespective of man's view-

point, change is biologically necessaryto maintain a healthy ecosystem.Resource managers have learned tomanipulate fire-caused changes inplant and animal communities to meettheir needs, and those of humankind ingeneral, while at the same time preser-ving underlying natural processes andfunctions. They do this by varying thetiming, frequency, and intensity of fire.

Prescribed Fire HistoryThe use of fire in the forests of the

United States has come full cycle. Ear-ly settlers found Indians using fire invirgin pine stands and adopted thepractice themselves to provide betteraccess, improve hunting, and to get ridof brush and timber so they couldfarm. Annual burning to "freshen up"

southern range became a custom. Thispractice, plus destructive wildfiresafter logging left millions of acres offorest land in the south devoid of trees.

The increasing wildfire problemcoupled with the need for a fire-freeinterval of several years to allow thepines to become reestablished ledmany foresters to advocate the exclu-sion of all fire from the woods. Others,however, pointed out that fire mighthave a place in the management oflongleaf pine. Fire has been used byprofessional foresters to reduce hazar-dous fuels since the turn of the century.The misconceptions and controversysurrounding the deliberate use of fireto achieve resource managementobjectives have slowly been replacedby facts. As knowledge accumulated,the use of prescribed fire grew.

Depression-era photo of unproductive forest land

Present UseToday prescribed fire is applied to

roughly 8 million acres in the Southeach year — about half of which areburned to achieve various forestmanagement objectives. Most of theremainder is for range and agriculturalpurposes. Prescribed burning is adesirable and economically soundpractice on most southern pine sites. Inmany cases, prescribed burning is theonly practical choice. Few, if any,alternative treatments have beendeveloped that can compete with firefrom the standpoint of effectivenessand cost. Chemical applicationsgenerally cost more than 10 times asmuch per acre as prescribed fire.Mechanical treatments such as disk-ing, chopping, or raking are at least 20times more expensive. Each of thesethree alternatives also has associatedenvironmental costs, such as destruc-tion of habitat and soil erosion. Boththe probability of causing damage, andthe magnitude of such damage, shouldit occur, need to be kept in mind.

In this guide, prescribed burning isdefined as fire applied in aknowledgeable manner to forest fuelson a specific land area under selectedweather conditions to accomplishpredetermined, well-defined manage-ment objectives.

This manual will be most useful inthe lower Piedmont and Coastal Plain.Prescribed burning in these areas hasbeen perfected by several generationsof resource managers. Although thepotential of prescribed fire in the upperPiedmont and mountains of the Southhas been demonstrated, few guidelinesexist. If you are interested in theemerging use of fire in the mountains,a good source of information and helpis your local State or Federal forestryoffice.

Impact of PrescribedBurning

A single prescribed burn canachieve multiple benefits. For examplea prescribed burn that consumes moredead fuel than it creates will reduce thefire hazard and, with few if anymodifications, will also improvewildlife habitat. Almost any prescribedburn improves access.

Prescribed fires aren't alwaysbeneficial, however. When conditionsare wrong, prescribed fire can severelydamage the very resource it was in-tended to benefit. Prescribed fire cantemporarily reduce air quality, butusually to a much lesser degree thanwildfire. For every prescribed fire op-portunity, there are tradeoffs thatshould be recognized and carefullyweighed before a decision is reached.Proper planning and execution are

necessary to minimize any detrimentaleffects to air quality. Potential off-sitei mpacts such as downstream waterquality should be carefully considered,as should on-site impacts to soil andaesthetics.

Public opinion is another factor toconsider because the general public isconcerned about the deterioration ofthe environment. Smoke fromprescribed fires, as well as fromwildfires, is highly visible. It is our jobas resource managers to inform thepublic of the differences betweenprescribed fire and wildfire—which oftenlook identical to the untrained eye.

Prescribed fire is a complex tooland should be used only by those trainedin its use. Proper diagnosis and detailedplanning are needed for every areawhere burning is contemplated. Theincomplete assessment of any factorcan pose serious liability questionsshould the fire escape or its smokecause damage. A prescribed fire thatdoes not accomplish it's intended ob-jective(s) is a loss of both time andmoney, and it may be necessary toreburn as soon as sufficient fuel ac-cumulates. Keep in mind that someresource management objectives canbe met with a single fire, some requireseveral fires in fairly quick succession,and some can only be accomplished byburning periodically throughout therotation.

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ReasonsFor Prescribed Fire In Forest Resource Management

■ Reduce hazardous fuels■ Prepare sites for seeding and planting■ Dispose of logging debris■ Improve wildlife habitat■ Manage competing vegetation■ Control disease■ Improve forage for grazing■ Enhance appearance■ Improve access■ Perpetuate fire-dependent species■ Cycle nutrients■ Manage endangered species

Reduce HazardousFuels

Forest fuels accumulate rapidly inpine stands on the Coastal Plain. In 5to 6 years, heavy "roughs" can buildup, posing a serious threat fromwildfire to all forest resources.

Prescribed fire is the most practicalway to reduce dangerous accumula-tions of combustible fuels undersouthern pine stands. Wildfires thatburn into areas where fuels have beenreduced by prescribed burning causeless damage and are much easier to

control. The appropriate interval be-tween prescribed burns for fuel reduc-tion varies with several factors,including the rate of fuel accumula-tion, past wildfire occurrence, valuesat risk, and the risk of a fire. The timeinterval between fires can be as oftenas every year although a 3- or 4-yearcycle is usually adequate after theinitial fuel-reduction burn.

The need to reduce hazardous fuelaccumulations in the pine plantationsof the South is increasing. Without fuelreduction, fire hazard is extremely

high in these vast contiguous stands.The initial hazard-reduction burn in ayoung pine stand requires exactingconditions of wind, humidity, andtemperature. Higher wind velocitiesand cooler temperatures minimizescorch damage. Southern pine planta-tions averaging 10 to 12 feet in heightcan be burned by experienced peopleunder the right conditions withoutdamage. Young plantations on in-dustrial lands arc often burned for thefirst time when they are 15 to 20 feettall using aerial ignition; close spacing

Winter backing fire in heavy rough Damaging wildfire in heavy rough3

Prescribed fire can improve wildlife habitat

of ignition spots (e.g., 2 chains by 2chains), and cool, damp conditionswith some wind are a must to avoidcrown damage.

Subsequent fuel reduction burnsneed not cover the entire area. The ob-jective is to break up fuel continuity.Fuel reduction on 75 to 80 percent ofthe area is sufficient. An added advan-tage of "patchy" burns is that the un-burned islands provide cover forwildlife. These unburned patches willnot have a dangerous accumulation offuels at the time of the next burn if theyresulted from a lack of fuel during theprevious fire. If, however, they weretoo wet to burn, these islands couldresult in a hot spot the next time if aheading fire was allowed to sweepthrough them under appreciably drierconditions. One reason excessivecrown scorch should be avoided isbecause, under some circumstances, itcan add more fuel to the forest floorthan the fire consumed.

Dispose of LoggingDebris

After harvest, unmerchantableli mbs and stems arc left either scat-tered across the area or concentrated atlogging decks or delimbing gates,depending upon the method of logging.This material is an impediment to bothpeople and planting equipment. If awildfire occurs within the next fewyears, fireline construction can beseverely hindered; the result beinglarger burn acreages and higherregeneration losses. Although not alllarge material will he consumed by aprescribed fire, what is left will he ex-posed so it can be avoided by tractor-plow operators. In stands that producea large amount of cull material, thedebris is often windrowed and burned.This practice should, however, beavoided whenever practical because ofsmoke management problems and thepotential for site degradation. Broad-cast burning is generally a much betteralternative. If the debris must be piledbefore burning, construct round"haystack" piles when the debris andunderlying ground are both fairly dry.This step will limit the amount of dirtin the pile. Piles containing largeamounts of dirt can seldom he burnedefficiently. They almost alwayssmolder for long peroids, creatingunacceptable smoke problems.

In some cases overstory pines areleft during harvest as seed trees, and inothers an unevenaged managementsystem such as shelterwood is used. Inboth situations, the logging debris canstill he burned, but you must take morecare to protect the remaining trees.

Prepare Sites forSeeding or Planting

Prescribed burning is useful whenregenerating southern pine by directseeding, planting, or natural regenera-tion. On open sites, fire alone can ex-pose adequate mineral soil and controlcompeting vegetation until seedlingsbecome established. Where competingvegetation cannot be adequately re-duced by fire, follow up withmechanical or chemical treatment.The fire will improve visibility so thatequipment operators can more easilysee the stumps of the harvested trees,as well as any other hazards. In addi-tion, if the area is to be bedded beforeplanting, burning first consumes muchof the debris. The result is more tightlypacked beds and thus better seedlingsurvival. Where herbicides are used tokill competition, subsequent burningwill give additional vegetation control.This step also permits more efficientand easier movement of hand-plantingcrews. Prescribed fire also recyclesnutrients, making them available forthe next timber crop.

For natural regeneration, knowledgeof anticipated seed crop and date ofearliest seed fall is essential. If the

seed crop is inadequate, burning canbe postponed. Complete mineral soilexposure is not necessary or desirable;a thin layer of litter should remain toprotect the soil. Generally, burningshould he done several weeks prior toseed fall. Timing varies with speciesand locality.

I mprove Wildlife HabitatPrescribed burning is highly recom-

mended for wildlife habitat manage-ment where loblolly, shortleaf,longleaf, or slash pine is the primaryoverstory species. Periodic fire tendsto favor understory species that requirea more open habitat. A mosaic ofburned and unburned areas tends tomaximize "edge effect" which pro-motes a large and varied wildlifepopulation. Deer, dove, quail, andturkey are game species that benefitfrom prescribed fire. Habitatpreferences of several endangeredspecies, including the Florida panther,gopher tortoise, indigo snake, and red-cockaded woodpecker are also enhancedby burning. Wildlife benefits fromburning are substantial. For example,fruit and seed production is stimulated.Yield and quality increases occur inherbage, legumes, and browse fromhardwood sprouts. Openings arecreated for feeding, travel, anddusting.

Selecting the proper size, frequency,and timing of burns is crucial to thesuccessful use of fire to improvewildlife habitat. Prescriptions should

4

Longleaf pine infected with brownspot needle blight

recognize the biological requirements(such as nesting times) of the preferredwildlife species. Also consider thevegetative condition of the stand and,most importantly, the changes fire willproduce in understory stature andspecies composition.

Manage CompetingVegetation

Low-value, poor-quality, shade-tolerant hardwoods often occupy or en-croach upon land best suited to grow-ing pine. Unwanted species may crowdout or suppress pine seedlings. In soilswith a high clay content and in areaswith low rainfall during parts of thegrowing season, competition for water,nutrients and growing space maysignificantly lower growth rates of theoverstory. Furthermore, understorytrees and shrubs draped with deadneedles and leaves act as ladder fuelsallowing a fire to climb into theoverstory crowns. In most situations,total eradication of the understory isneither practical nor desirable.

However, with the judicious use ofprescribed fire, the understory can bemanaged to limit competition withdesired species while at the same timeproviding browse for wildlife.

Burning is most effective in con-trolling hardwoods less than 3 inchesin diameter at the ground line. Periodicfires throughout the rotation can keepcompeting vegetation below this 3-inchthreshold. The most desirable seasonfor burning and the frequency of burnswill vary somewhat by species andphysiographic region. Generally, awinter (dormant season) fire results inless root kill than a late spring or sum-mer burn. One system recommendedin both the Piedmont and Coastal Plainis a dormant season burn to reduce in-itial fuel mass, followed by two ormore annual (if enough fuel is present)or biennial summer burns.

If not controlled, the hardwoodswill form a midstory and capture thesite once the pine is harvested. If alarge pine component is wanted in thenext rotation, these unmerchantablehardwoods must be removed duringsite preparation — an expensive

proposition. Generally, fire is requiredin combination with other treatmentsinvolving heavy equipment, chemicals,or both. In many locations the prefer-red system is a combination summerburn and herbicide treatment.However, in the lower Appalachians ofSouth Carolina. another relatively in-expensive technique is employed. Allresidual hardwoods arc felled and thearea broadcast burned under exactingfuel and weather conditions.

Control Insects AndDisease

Brownspot disease is a fungal infec-tion that may seriously weaken andeventually kill longleaf pine seedlings.Diseased seedlings tend to remain inthe grass stage. Control is recom-mended when more than 20 percent ofthe seedlings are infected or whensome of the diseased seedlings areneeded for satisfactory stocking. Oncethe seedlings become infected, burningis the most practical method of diseasecontrol. Any type of burning that kills

Warm-season grasses promoted by summer burning

the diseased needles without killing theterminal bud is satisfactory. Burningthe infected needles reduces thenumber of spores available to infect theseedlings. Generally a fast-movingwinter heading fire under damp condi-tions, as exist after passage of a strongcold front, is best. Height growth ofthe seedlings often begins the firstpostfire growing season.

Reinfection usually occurs quicklyif there are infected seedlings in un-burned areas near the burned area. Ifreinfection occurs, additional burnsmay be needed. However, longleaf ismost susceptible to fire immediatelyafter it comes out of the grass stage.Therefore, a reburn will likely killsome seedlings, so such a decisionshould be made in consultation with

Prescribed fire improves range habitat

experienced personnel. Your localState forestry office is a good place tobegin.

Prescribed burning seems to reduceproblems from Fomes annosus rootrot. This fungal disease is less frequentwhere periodic burns have reduced thelitter. The fire alters the microenviron-ment of the forest floor and perhapsdestroys some fruiting bodies andcauterizes tree stumps.

Prescribed fire has been success-fully used under very exacting fuel andweather conditions to control cone in-sects such as the white pine cone beetle(Conophthorus coniperda) while thepest is overwintering in cones on theground. Prescribed burning costsmush less than traditional chemicalcontrol methods used to control thisbeetle.

I mprove Forage forGrazing

Prescribed burning improvesgrazing in open pine stands on theCoastal Plain. Low-intensity burnsincrease availability, palatability,quality, and quantity of grasses andforbs. Dead material low in nutrientvalue is removed while new growthhigh in protein, phosphorus, andcalcium becomes readily available.These benefits are manifested inincreased seasonal cattle weightgains. Cattle congregate on recentlyburned areas so burn location andsize must be carefully selected to pre-vent overgrazing. One commonlyused system is to divide the range in-to three parts and burn one thirdevery year.

A plant may become more — orless — abundant after a fire. Theresult depends on the stage in theplant's life cycle at the time of thefire. Flowering dates vary amongspecies and with latitude and eleva-tion within a species' range. There-fore, observe these dates for thepreferred species, and time the burnaccordingly. For example, wiregrassresponds much better to summerburns than it does to dormant seasonburns.

Enhance AppearancePrescription burning improves

recreation and aesthetic values. Forexample, burning maintains openstands, produces vegetative changes,and increases numbers and visibilityof flowering annuals and biennials.Burning also maintains open spacessuch as mountain balds, and createsvistas. Unburned islands increasevegetative diversity which attracts awider variety of birds and animals. Apractical way to maintain manyvisually attractive vegetative com-munities and perpetuate many en-dangered plant species is through theperiodic use of prescribed fire.

Using fire to manage landscapesand enhance scenic values requiresjudiciously planned and executedburns, especially where exposure tothe public is great. Burning tech-niques can be modified along roadsand in other heavily used areas to en-sure low flame heights, which in turnwill reduce crown scorch and barkchar while still opening up the standand giving an unrestricted view.

6

Limited access due to fire exclusion

Open stand resulting from annual winter burning

Pitcher plants respond to prescribed fire

Improve AccessBurning underbrush prior to the

sale of forest products improves theefficiency of cruising, timber mark-ing, and harvesting. Removing ac-cumulated material before harvestingalso provides greater safety forti mber markers, loggers and navalstores operators due to better visi-bility and less underbrush. Thereduced amount of fuel helps offsetthe greater risk of wildfire duringharvesting. Moreover, the improvedvisibility and accessibility often in-crease the stumpage value of theproducts. Hikers and other users alsobenefit from easier travel and in-creased visibility. Hunters are morelikely to get a clear shot.

Perpetuate Fire-dependent Species

Many plants have structuraladaptations, specialized tissues, orreproductive features that favor themin a fire-dominated environment.Such traits suggest a close associationwith fire over a very long period oftime. Many endemics are only foundthe first 1 to 2 years after a fire.Changes in the "natural" fire patternas a result of attempted fire exclusionhave led to dramatic decreases inmany of these fire-tolerant or fire-dependent species. Many picturesqueflowers, including several orchids,currently listed as threatened or en-dangered are benefited by fire.

Prescribed burning, however, doesnot automatically help perpetuateplant and animal species becausefires are not necessarily conductedduring the same season in which thesite historically burned. The intervalbetween prescribed fires as well asfire intensity may also differ fromthose of the past. The individualrequirements of a species musttherefore be understood before a firecan be prescribed to benefit that species.

Prescribed Burning=Good Wildlife Habitat

7

Backing fires produce less smoke

than heading tires

As a stand matures, an increasingproportion of the nutrients on the sitebecome locked up in the vegetationand are unavailable for futher use un-til plants die and decompose. Low-intensity fires speed up this recyclingprocess, returning nutrients back tothe soil where they are again availableto plants. Under many conditions,burning may increase nitrogen fixa-tion in the soil and thus compensatefor nitrogen loss to the atmospherethat results from burning the litterlayer. When duff layers are not com-pletely consumed, changes in soilpore space and infiltration rate arevery slight. If mineral soil isrepeatedly exposed, rain impact mayclog fine pores with soil and carbonparticles, decreasing infiltration ratesand aeration of the soil.

A major concern of the forestmanager is how fires affect surfacerunoff and soil erosion. On mostLower and Middle Coastal Plainsites, there is little danger of erosion.In the steeper topography of the Up-per Coastal Plain and Piedmont,some soil movement is possible.However, if the burn is under atimber stand and some duff remains,soil movement will be minor onslopes up to 25 percent. The amountof soil movement will be greater aftersite preparation with heavy machinerythan after prescribed burning.

Care must be taken when clearcutlogging slash is burned on steepslopes. Until grass and other vegeta-tion cover the site, surface runoff andsoil erosion may occur. The burning

phase of the "fell and burn" site-preparation technique commonly usedin the upper Piedmont and mountainsshould be completed by mid-September.This timing allows herbaceous plantsto seed in and provide a winterground cover. Burning should not bedone if exposure of highly erosivesoils is likely.

Soil should be wet or damp at theti me of burning to ensure that anorganic layer will remain after aprescribed burn. Moisture not onlyprotects the duff layer adjacent to thesoil, but also prevents the fire fromconsuming soil humus. If the forestfloor is completely consumed, themicroenvironment of the upper soillayer will he drastically changed,making conditions for near-surfacetree roots very inhospitable. Dampsoil also aids mopup after the burn.

Effects on WaterThe main effect of prescribed

burning on the water resource is thepotential for increased runoff of rain-fall. When surface runoff increasesafter burning, it may carry suspendedsoil particles, dissolved inorganicnutrients, and other materials intoadjacent streams and lakes reducingwater quality. These effects seldomoccur after Coastal Plain burns. Pro-blems can be avoided in hilly areasor near metropolitan water suppliesby using properly planned and con-ducted burns.

Rainwater leaches minerals out ofthe ash and into the soil. In sandy

soils, leaching may also move mineralsthrough the soil layer into the groundwater. Generally, a properly plannedprescribed burn will not adverselyaffect either the quality or quantity ofground or surface water in the South.

Effects on AirPrescribed fires may contribute to

changes in air quality. Air quality ona regional scale is affected only whenmany acres are burned on the sameday. Local problems are more fre-quent and occasionally acute due tothe large quantities of smoke that canbe produced in a given area during ashort period of time.

Smoke consists of small particles(particulate) of ash, partly consumedfuel, and liquid droplets. Other com-bustion products include invisiblegases such as carbon monoxide, car-bon dioxide, hydrocarbons, and smallquantities of nitrogen oxides. Oxidesof nitrogen are usually produced attemperatures only reached in piled orwindrowed slash or in very intensewildfires. In general, prescribed firesproduce inconsequential amounts ofthese gases. Except for organic soils(which are not generally consumed inprescribed burns), forests fuels con-tain very little sulfur, so oxides ofsulfur are not a problem either.

Particulates, however, are ofspecial concern to the prescribedburner because they reduce visibility.The amount of particulate put intothe air depends on amount and typeof fuel consumed, fuel moisture con-tent, and rate of fire spread as deter-

Smoke sensitive areas can be impacted by prescribed fire

mined by timing and type of firingtechnique used. Rate of smokedispersal depends mainly on atmos-pheric stability and windspeed.

Effects of smoke can be managedby burning on days when smoke willblow away from smoke-sensitive-areas. Precautions must be takenwhen burning near populated areas,highways, airports, and other smoke-sensitive areas. Weather and smokemanagement forecasts arc available asa guide for windspeed and direction.Any smoke impact downwind must

be considered before lighting the fire.The burner may be liable if accidentsoccur as a result of the smoke. Allburning should be done in accord-ance with applicable smoke manage-ment guidelines and regulations.During a regional alert when highpollution potential exists, all pre-scribed burning should be postponed.

Nighttime burning should be donewith additional care because a tem-perature inversion may trap thesmoke near the ground. This smokecan create a serious visibility hazard,especially in the presence of highhumidities (which occur on mostnights). In particular, smoke mixingwith existing fog will drasticallyreduce visibility. Cool air drainage atnight will carry smoke downslope,causing visibility problems in low-lands and valleys. On the CoastalPlain, nighttime air drainage oftenfollows waterways. Conditions can beespecially hazardous near bridgecrossings because of the higherhumidity there. Of course, the earlier

in the day a fire is completed, theless likely it is to cause nighttimesmoke problems. More completemopup following daytime burningand nighttime burning only undervery stringent prescriptions canminimize the occurrence of theseproblems. Your local State forestryoffice can help with planning night-ti me burns.

Effects on HumanHealth and Welfare

Occasional brief exposure of thegeneral public to low concentrationsof drift smoke is more a temporaryinconvenience than a health problem.High smoke concentrations can,however, be a very serious matter,particularly near homes of peoplewith respiratory illnesses or nearhealth-care facilities.

Smoke can have negative short-and long-term health effects. Firemanagement personnel who are exposedto high smoke concentrations oftensuffer eye and respiratory systemirritation. Under some circumstances,continued exposure to high concen-trations of carbon monoxide at thecombustion zone can result in impairedalertness and judgement. The proba-bility of this happening on a prescribedfire is, however, virtually nonexistent.

Over 90 percent of the particulateemissions from prescribed fire aresmall enough to enter the humanrespiratory system. These particulatescan contain hundreds of chemicalcompounds, some of which are toxic.

The repeated, lengthy exposure torelatively low smoke concentrationsover many years can contribute torespiratory problems and cancer. But,the risk of developing cancer fromexposure to prescribed fire has beenestimated to be less than 1 in amillion.

Although the use of herbicides inforest management has increased allchemicals are now tested before beingapproved for use, and we arc morecareful than ever to minimize theirpotential danger. Many of them breakdown rapidly after being applied.Moreover, both theoretical calcula-tions and field studies suggest thatprescribed fires are hot enought todestroy any chemical residues.Minute quantities that may end up insmoke are well within currently-accepted air quality standards.Threshold limit values (TLV's) areoften used to measure the safety ofherbicide residues in smoke. Ex-pected exposure rates of workers tovarious brown-and-burn combinationshave been compared with TLV's.They showed virtually no potentialfor harm to workers or the generalpublic.

There is at least one group ofcompounds carried in smoke that canhave an immediate acute impact onindividuals. When noxious plantssuch as poison ivy burn, the smokecan cause skin rashes. These rashescan be much more widespread on thebody than those caused by direct con-tact with the plants. If you breathethis smoke, your respiratory systemcan also be affected.

Effects on WildlifeThe major effects on wildlife are

indirect and pertain to changes infood and cover. Prescribed fires canincrease the edge effect and amountof browse material, thereby improv-ing conditions for deer and otherwildlife. Quail and turkey favor foodspecies and semi-open or open condi-tions that can be created and main-tained by burning. Burning can im-prove habitat for marshland birds andanimals by increasing food produc-tion and availability.

The deleterious effects of prescribedfire on wildlife can include destructionof nesting sites and possible killing ofbirds, reptiles, or mammals trappedin the fire. Fortunately, prescribedfires can be planned for times when

Aesthetics can be enhanced by prescribed fire

nests are not being used. Also,virtually all the types of prescribedfire used in the South provide ampleescape routes for wildlife. For example,a large tract was operationally burnedwith aerially-ignited spot fires andimmediately examined for wildlifemortality. Fish and game agencypersonnel found none, but noted deermoving back into the still-smokingburn. The ill-advised practice oflighting all sides of a burn area (ringfiring) is a primary cause of animalentrapment and has no place in under-burning. It also results in unnecessarytree damage as the flame fronts mergein the interior of the area.

Management of the endagered red-cockaded woodpecker presents aspecial problem because of thecopious amounts of dried resin thatstretch from the nest cavity towardthe ground. The bird requires habitathistorically maintained by fire, eventhough these pitch flows can beignited, carrying fire up to the cavity.This is unlikely, however, if shortflame lengths are prescribed. Fuelcan also be raked from around cavitytrees as an added precaution.

Prescribed fire does not benefitfish habitat, but it can have adverseeffects. Riparian zone (streamside)vegetation must be excluded fromprescribed burns to protect highquality plant and animal habitat, andwater quality. When shade is removed,water temperatures will increase.Burning conditions are often un-favorable along streams because ofincreasing fuel moisture, making lineplowing optional. But a buffer zoneshould always be left. If in doubt, acontrol line should be put in.

Effects on AestheticsThe principal effect of prescribed

burning on aesthetics can be sum-marized in one word: contrast. Con-trast, or change from the preburnlandscape, may be postive or negativedepending largely on personal opinion.What may be judged an improvementin scenic beauty by one may be con-sidered undesirable by another.

Many of the undesirable impactsare relatively short term and can beminimized by considering scenicqualities when planning a burn. Forexample, the increased turbulenceand updrafts along roads and otherforest openings will cause more in-tense fire with resulting higher treetrunk char and needle scorch.

Generally, the more immediate un-favorable impacts such as smoke andash, topkilled understory plants, anda blackened forest floor are necessaryto achieve two major benefits —increased visual variety and increasedvisual penetration.

Variety or diversity in vegetativecover will create a more pleasing,general visual character to the stand.Similarly, scenic qualities of the forestcan be better appreciated if the standcan be made more transparent. Anexample is the reduction of an under-story buildup along a forest road thatwill permit the traveler to see into theinterior of the stand, perhaps to alandscape feature such as a pond or

interesting rock outcrop. The smuttyappearance of the ground will "greenup" fairly quickly. Any scorched needleswill soon drop and not be noticeable.Flowers and wildlife will increase.

Some important points are: 1) Theapparent size of a burn can be reducedby leaving unburned islands to createa mosaic pattern of burned and un-burned area. 2) Where hardwood in-clusions are retained, make sure theyare large enough to be relevant to theobserver. 3) Observer criteria must beunderstood if reactions to a burn areto be predicted. Personal reactionswill depend on observer distance,duration or viewing time, and aspect.

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Weather and FuelConsiderationsImportant WeatherElements

A general understanding of theseparate and combined effects ofseveral weather elements on thebehavior of fire is needed if you areto plan and execute a good burn.Wind, relative humidity, temperature,rainfall, and airmass stability are themore important elements to consider.These factors influence fuel moisturewhich is critical to success. Becauseweather and fuel factors interact, anexperienced prescribed burner canconduct a successful burn even withone or more factors slightly outsidethe desired range as long as they areoffset by other factors. You shouldbecome familiar with local weatherpatterns that are favorable forprescribed burning as well as local"watchout" situations.

Good winter prescribed burningconditions often exist for several daysafter the passage of a cold front thathas brought 1/4 to 3/4 inch of rain.During this time, persistent winds,low relative humidities, cool tempera-tures and sunny days can beanticipated. Weather conditions forsummer burning are much lesspredictable.

Before starting to burn, obtain thelatest weather forecast for the day ofthe burn and the following night.When possible, get a 2-day weatheroutlook. Knowledge of weather isthe key to successful prescribedburning, and is mandatory forproper management of smokeproduced by burning.

13

Knowledge of weather is essential for a successful burn Successful backing fires need steady winds

Sources of WeatherInformation

Ordinarily, four sources ofweather information are available.Use one or more of them before andduring prescription fires. The sourcesare:■ NATIONAL WEATHER

SERVICE■ STATE FORESTRY AGENCIES■ LOCAL OBSERVATIONS■ PRIVATE WEATHER

FORECASTING SERVICESLocal National Weather Service

offices will furnish weather forecastsand outlooks via radio and television.Spot weather forecasts are alsoavailable, but their value dependsupon the forecaster's knowledge oflocal conditions. Inexpensive radiosare also available that continuallymonitor National Oceanic and At-mospheric Administration (NOAA)weather-related information andforecast updates. Do not rely solelyon the NOAA broadcasts because thisinformation is not specific enough forsmoke-management planning.

The best source of information in-cluding current forecasts and outlooksis generally the local office of yourState forestry agency. The person youtalk to can often help you interpretthe forecast, give you any warnings,and pass on pertinent informationsuch as other burns planned for thatday, The prescribed burner shouldtake full advantage of such services.

All southern State forestry agen-cies and national forests, as well asmany military bases and private con-cerns operate fire-danger stations.The basic weather parametersmeasured at these sites are veryuseful. However, National Fire

14

Danger Rating System (NFDRS)indices which are calculated fromthese measurements should not heused. This system was designed toprovide a worst-case scenario forwildfire control over very large areas.It was not designed as a planning toolfor prescribed burning!

Weather observations should bemade at the prescribed burn sitei mmediately before, during and im-mediately after a fire. Such observa-tions are important because theyserve as a check on the applicabilityof the forecast and keep the burningcrew up-to-date on any local in-fluences or changes. Take readings ina similar area upwind of the fire toavoid heating and drying effects ofthe fire. Do this at 1- to 2- hour inter-vals, or more often if changes in firebehavior are noticed. Measurementstaken in an open area, on a forestroad, and in a stand are likely to dif-fer widely. Easy-to-use belt weatherkits that include a psychrometer andan anemometer are available. Byusing this kit and observing cloudconditions, a competent observer canobtain a fairly complete picture of thecurrent weather.

WindUnderburning

Prescribed fires behave in a morepredictable manner when windspeedand direction are steady. Onsitewinds vary with stand density andcrown height. Windspeed generallyincreases to a maximum in the earlyafternoon and then decreases to aminimum after sunset. The preferredrange in windspeed in the stand is 1to 3 mph (measured at eye-level) formost fuel and topographic situations.

Windspeed readings for most fire-weather forecasts are, however, taken20 feet above ground at open loca-tions. Windspeeds in fire-weatherforecasts are the maximum expectedand not the average for the day. Theminimum 20-foot windspeed for burningis about 6 mph and the maximum isabout 20 mph. These are the mostdesirable winds for prescribed burning,but specific conditions may tolerateother speeds. As a general rulehigher windspeeds are steadier indirection.

Relatively high winds quicklydissipate the heat of a backing fire.The result is less crown scorch thanfrom a fire backing into a low-speedwind. In-stand windspeeds should bein the low to middle range (1 to 2mph) when heading fires are used.With high winds, heading firesspread too rapidly and become toointense. On the other hand, enoughwind must be present to keep theheat from rising directly into treecrowns. Mature southern pine standswith a sparse understory can beburned at very low windspeeds —just enough to give direction to thefire.

Of greater importance than wind-speed is the length of time the windblows from one direction. Presistentwind directions occur frequently dur-ing winter, especially followingpassage of a cold front when windsare typically from the west ornorthwest. As these winds slowlyshift clockwise over the next fewdays, they become weaker and lesssteady. Winds with an easterly com-ponent are generally consideredundesirable for prescribed burning.However, along the coast, sea andland breezes are often utilized. Ir-

The belt weather kit and additional wind meter

respective of direction, a forecast ofwind steadiness should always be ob-tained. For sites near the coast, alsoobtain the expected time of seabreeze arrival and departure.

The most critical areas, withregard to fuel and topography, shouldbe burned when wind direction issteady and persistent. Relatively easyburns can be conducted under lessdesirable wind conditions. Topography,and local effects such as stand open-ings, roads, etc. may have a bearingon favorable wind conditions andshould always he considered whenplanning a burn.

PREFERRED IN-STAND WIND:1 MPH to 3 MPH

Debris BurningWinds are stronger in open areas

than they are in the forest. Becausethere is no overstory to protect, windis not needed to cool the heated com-bustion products. However, from asmoke management standpoint, thestronger the wind the better thedispersion—provided there are nodownwind smoke-sensitive areas thatwill be impacted. When broadcastburning, eye-level winds over 3 to 4mph can create containment problemsif a heading fire is used. With piledor windrowed debris, eye-level windsof 8-10 mph can be tolerated by ad-justing the firing pattern.

Wind direction may changesubstantially with height, but it isthese transport winds that regulate

the movement of the smoke column.Moderate transport windspeeds allowa convection column to develop thatexhausts the smoke high into theatmosphere where it quickly disperseswith a minimum impact on ground-level air quality. Before setting a firethat will generate a convection col-umn, however, obtain information onthe existing and forecast wind pro-files. If an adverse profile exists, it islikely to result in an unacceptablyhigh spotting potential. Fire behaviorcharacteristics are associated Withvarious wind profiles. They aredescribed in Byram's publication,listed in the Suggested Readingsection. Once the fire has died downand smoke production is fromsmoldering combustion, surface windis necessary to ensure good smokedispersion.

Relative HumidityUnderburning

Relative humidity is an expressionof the amount of moisture in the aircompared to the total amount the airis capable of holding at that temperatureand pressure. Each 20° rise in temp-erature (which often occurs duringthe morning hours on a clear day)reduces the relative humidity byabout half, and likewise, each 20°drop in temperature (which often oc-curs in early evening) causes relativehumidity to roughly double. When acold front passes over an area, the airbehind the front is cooler and drierthan the old airmass it is replacing.The result is a drop in both

temperature and humidity.Preferred relatiye humidity for

prescribed burning varies from 30 to55 percent. Under special conditions,a wider range of relative humidities,as low as 20 percent and as high as60 percent, can produce successfulburns. When relative humidity fallsbelow 30 percent, prescribed burningbecomes dangerous. Fires arc moreintense under these conditions andspotting is much more likely; pro-ceed only with additional precau-tions. When the relative humidity is60 percent or higher, a fire may leaveunburned islands or may not burn hotenough to accomplish the desiredresult.

The moisture content of fine, deadfuel such as pine needles and driedgrasses responds rapidly to changesin relative humidity. However, thereis a timelag involved for fuels toachieve equilibrium with the moisturecondition of the surrounding at-mosphere. Also, previous drying andwetting will influence fuel moisture.Therefore, the relative humidity andfuel moisture must be assessedindependently.

PREFERRED HUMIDITY:30 TO 55 PERCENT

Debris BurningRelative humidity (along with

temperature) controls fuel moisturecontent up to about 32 percent.Liquid moisture such as rain or dew

must contact a fuel for moisture con-tent to rise above 32 percent, and theincrease depends upon duration aswell as the amount of precipitation.

Recently-cut pine tops have a dry-ing rate that is somewhat independentof relative humidity as long as themositure content of fresh tops(needles still green) is above about 32percent. Once this material initiallydries to a moisture content below 32percent, it behaves as a dead fuel andbecomes much more responsive todaily fluctuations in relative humidity.The response to changes in relativehumidity is much more rapid in finedead fuels suspended above theground than in those that havebecome part of the litter layer. Theseelevated needles and other suspendeddead materials are not in contact withthe damp lower litter and are moreexposed to the sun and wind.

When burning piled debris, oncethe larger-diameter fuels ignite, in-creases in relative humidity have littleeffect on fire behavior during the ac-tive burning phase. Low humidities(below 30 percent), however, willpromote spotting and increase thelikelihood of tire spreading betweenpiles.

TemperatureUnderburning

The average instantaneous lethaltemperature for living tissue is about145°F. Air temperatures below 60°Fare recommended for winter under-burns because more heat is needed toraise foliage or stem tissue to lethaltemperature levels. When the objec-tive is to control undesirable species,growing-season burns with ambientair temperatures above 80°F arerecommended. These conditions in-crease the likelihood of reaching kill-ing temperatures in understory stemsand crowns. Of course, the overstorypines must be large enough to escapeinjury. Larger trees have thicker barkand their foliage is higher above theflames, which allows more room forthe hot gases to cool before reachingthe crowns.

Temperature strongly affectsmoisture changes in forest fuels.High temperatures help dry fuelsquickly. When fuels are exposed todirect solar radiation, they becomemuch warmer than the surroundingair. Moisture will move from thewarmer fuel to the air even thoughthe relative humidity of the air is

high. Temperatures below freezing,on the other hand retard fire intensitybecause additional heat is required toconvert ice to liquid water before itcan be vaporized and driven off assteam. Consequently, it does not takemuch moisture under these conditonsto produce a slow-moving fire thatwill leave unacceptably large areasunburned.

PREFERRED WINTERTEMPERATURE:

BELOW 60°F

Debris BurningCleared areas are often burned

when ambient air temperatures arehigh. There is no overstory present toworry about and surface heating fromdirect sunlight usually increases themixing height which helps dispersethe smoke.

It is particularly important to usean ignition pattern such as centertiring when ambient air temperaturesare high. This tactic draws the heatinto the cleared area and preventsheat damage to trees in adjacentstands.

Rainfall and SoilMoistureUnderburning

Because rainfall affects both fuelmoisture and soil moisture, youshould have some idea of the amountof rain falling on the area to beburned. In winter, rainfall is fairlyeasy to forecast throughout the South.In summer, when shower activityprevails, predicting rainfall at in-dividual locations is much moredifficult. The only reliable method todetermine the amount of precipitationthat actually falls is to place aninexpensive rain gauge on the site.

The importance of adequate soilmoisture can't be overemphasized.Damp soil protects tree roots andmicroorganisms. Even when burningto expose a mineral soil seedbed it isdesirable to leave a thin layer oforganic material to protect the soilsurface. Burning should cease duringperiods of prolonged drought andresume only after a soaking rain ofat least 1 inch. As soil moisture con-ditions improve, less rain is neededbefore burning. If recent precipitationhas been near average, 1/4 to 1/2 inchof rain followed by sunny skies, brisk

winds, and low humidities willgenerally result in several days ofgood prescribed fire conditions withadequate soil protection.

On clay soils, such as are found inthe Piedmont, much of the rainfall islost through surface runoff, and dura-tion is more important than amount.For example, 1 inch of rain occurringin 1/2 hour will not produce as largea moisture gain as 1/2 inch fallingover a 2 hour period.

PREFERRED SOILMOISTURE: DAMP

Debris BurningGenerally, rain has a much greater

effect on fuel moisture in clearedareas than under a stand becausenone is intercepted by tree canopies.However, fuels also dry much fasterin cleared areas because of increasedsunlight and higher windspeeds. Thisdifferential drying can often be usedto advantage from a fire-controlstandpoint. Burn the cleared areaseveral days after a hard rain whilefuels in the surrounding forest arestill damp. Burning under these con-ditions assures good soil moisture.However, when burning clearedareas, soil damage is as much a func-tion of fire intensity and duration asit is of soil moisture. Intense, long-duration fires will bake the soilregardless of the moisture present.Both the chemical and physical prop-erties of the soil can be altered. Thistype of fire should be avoided,especially on clay soils and steepslopes. These undesirable fire effectsare often produced when burningwindrowed or piled debris, and areone reason piling or windrowingslash prior to burning arediscouraged.

Fine-fuel MoistureUnderburning

Fine-fuel moisture is strongly in-fluenced by rainfall, relative humidity,and temperature. The preferred rangein actual (not calculated) fine-fuelmoisture of the upper litter layer (thesurface layer of freshly fallen needlesand leaves) is from 10 to 20 percent.Burning when fine-fuel moisture isbelow 6 or 7 percent can result indamage to plant roots and even thesoil. When fine-fuel moisture ap-

16

Fuel-moisture sticks Effects of humidity and days since rain on fine-fuelmoisture

proaches 30 percent, fires tend toburn slowly and irregularly, oftenresulting in incomplete burns that donot meet the desired objectives.However, when areas with very heavyfuel buildups or extensive drapedfuels are burned, moisture contentshould be 20 to 25 percent to keepfire intensity manageable, especiallyif aerial ignition techniques are used.Fine-fuel moisture values obtainedfrom NFDRS tables on fire-behaviormodels are considerably less thanthese actual values.

Some experienced practitionerscan accurately estimate fuel moistureby examining a handful of litter.However, the only sure way to tell isto take a sample and ovendry it.Tables and equations in the NationalFire Danger Rating System andBEHAVE can be used to estimatefine-fuel moisture, but the results areinvariably underestimates (becausethey are worst-case values designedfor use in predicting wildfirebehavior). One simple test that willgive a very rough estimate of theupper-litter-layer moisture content isto pick up a few pine needles and in-dividually bend each in a loop. If theneedles snap when the width of theclosing . loop is about 1/4 to 1/2 inch,their moisture content is between 15and 20 percent. If they do not snapin two, they are too wet to burn well.If they crumble into small pieces theyare exceedingly dry and even if thelower litter is moist, the fire maycause damage and be difficult to con-trol. Fuel moisture sticks that respondto weather changes like 10-hour fuelsare available. With a good set ofscales and proper placement of thesticks, acceptable fuel moisture

estimates can be obtained just beforeignition. These values will differslightly from actual fine-fuelmoistures, but are fairly represen-tative of most southern fuel types.They are much closer to actual fine-fuel moistures than are calculated ortabular values.

Lower litter should always bechecked before burning to make sureit feels damp. This will help ensurethat some remains, even though char-red, to leave a protective coveringover the soil. Generally, the moisturecontent increases from the litter sur-face down through the duff layer tothe soil. Exceptions can occur after alight shower, or in the morning aftera heavy dew. In these cases, firesoften burn more intensely than wouldbe expected from just looking at theupper-litter-layer moisture content.When burning on organic soils thisphenomenon can have drastic conse-quences. If the fire dries the moistsurface layer of peat, the organic soilwill ignite. These fires can impact anarea for many weeks in spite of con-trol efforts, causing extensive smokeproblems.

The speed with which fine fuelsrespond to changes in humiditydepends on fuelbed characteristicssuch as whether the fuelbed consistsof compacted hardwood leaves orjack-strawed pine needles. Differentfuel types can reach different moisturecontents under the same humidityconditions. For example, grassyopenings containing cured materialcan be burned within hours of adrenching rain if good drying condi-tions exist. Because of these naturalvariations, recommended fine-fuelmoisture values are only guidelines.

On-the-ground knowledge of fuelsmust be incorporated into theprescription.

Fuel moisture also influencessmoke production. When very dampwoody fuels burn, large amounts ofcharacteristic white smoke are givenoff. Much of the visible smoke plumeis actually condensed water vapor.

PREFERRED FINE-FUELMOISTURE:

10 TO 20 PERCENT

Debris BurningHarvested areas should be burned

when fuels are dry. They will igniteeasier, burn more quickly and com-pletely, shortening the time necessaryto complete the burn. Less mopupwill he required and the impact onair quality will be reduced. The shortbut severe summer droughts commonthroughout much of the South pro-vide ideal burning conditions oncleared areas, provided soil moisturedoes not get too low.

To avoid the possibility of un-necessary damage to the site, debrisshould be burned as it lies (broadcastburned) rather than piled. Becausefuels on logged areas receive fullsolar radiation, they dry before sur-rounding forest fuels do. It takes atleast several weeks after cutting forthe severed tree tops to cure. Oncethe needles turn a greenish-yellow

Prescribed Burned Forestsare More Productive

17

and the hardwood leaves wither, thedebris is ready to burn. Cleared areascan then be safely burned soon aftera rain, before adjacent forest fuelsdry enough to burn well. Ten-hourfuel moisture (fuels 1/4 to 1 inch indiameter, such as branches and smallstems) is a better indicator of burningconditions in slash fuels than is fine-fuel moisture. Fuel moisture stickswill give excellent results. One set of"sticks" can be placed on the area tobe burned and another in the nearbyundisturbed forest. Let the sticksbecome acclimated for at least 2weeks before reading. Manymanagers consider the area ready toburn when the moisture content ofthe sticks on the logged area reachesabout 10 percent while that of thosein the forest is still above 15 percent.

If the burn objective is to consumelarger fuels (over 2 to 3 inches indiameter), piling will probably benecessary. Piling in wet weathershould be avoided. Keep the pilessmall and free of dirt. Allow freshlogging debris to cure for severalweeks before piling because dryingconditions are exceedingly poor inthe middle of a pile, especially if it iscompacted or contains much dirt.Much of the smoke problem associatedwith burning piled debris is causedby inefficient combustion of damp,soil-laden piles. These piles maysmolder for days or weeks.

Airmass Stability andAtmospheric DispersionUnderburning

Atmospheric stability is theresistence of the atmosphere to verticalmotion. When the atmosphere isstable, temperature decreases slowlyas altitude increases (less than 5.5°Fper 1,000 feet). Under very stableconditions, inversions may develop inwhich temperature actually increaseswith height. The distance from theground to the base of this inversionlayer is called the mixing height.Under less stable atmospheric condi-tions, other factors beyond the scopeof this discussion determine theheight of the mixing layer. In eithercase, the mixing layer is defined asthe layer of air within which vigorousmixing of smoke and other pollutantstakes place. The average windspeedthroughout the mixing layer is calledthe transport windspeed. Mixingheights above 1,700 feet and transport

windspeeds above 9 mph arcdesirable for good smoke dispersion.Some prescribed burners on theOzark Plateau believe their firesbecome difficult to control when themixing height is greater than 6,500feet.

The old adage that hot air rises istrue but only as long as it is warmerthan the surrounding air. Thus, stableair tends to restrict convection col-umn development and produces moreuniform burning conditions.However, combustion products areheld in the lower layer of the at-mosphere (especially undertemperature inversions). Visibility isli kely to be reduced because ofsmoke accumulation. As the earthcools each night, the air near theground is cooled more than the airabove, forming a stable layer.Because this cold air is denser, itdrains into low-lying areas such asswamps and bottomlands, carryingwith it smoke from smolderingstumps, branches and other debris.

When the atmosphere is unstable,the decrease in temperature withheight exceeds 5.5°F per 1,000 feet.Once a parcel of air starts to rise, itwill continue to rise until it cools tothe temperature of the surroundingair. Such conditions promote convec-tion and rapid smoke dispersion but,if severe, can make fire controldifficult.

A neutral atmosphere is one inwhich a rising parcel of air remainsat the same temperature as its sur-rounding environment (i.e., thetemperature decrease with altitudeequals the dry adiabatic lapse rate of5.5°F per 1,000 feet). Smoke disper-sion in a neutral atmosphere can beadequate if windspeed is sufficientlyhigh. But remember, you need to ac-count for the effect of the wind onfire control.

Obtain forecasts of mixing height,transport windspeed, and atmosphericstability, but also observe local in-dicators at the fire site. Indicators ofa stable atmosphere arc steady winds,clouds in layers, and poor visibilitydue to haze and smoke hanging nearthe ground. Unstable conditions areindicated by dust devils, gusty winds,clouds with vertical growth, andgood visibility.

A prescribed fire generates verticalmotion by heating the air. If the at-mosphere is unstable, the hot com-bustion products will rise rapidly

because of the large temperature dif-ference between the smoke and sur-rounding air. The column will con-tinue to build in height as long as itremains relatively stationary and isheated by new combustion productsfaster than it is being cooled. Thestronger the convective activity, thestronger the indrafts into the fire.This effect increases fire intensity byproducing even stronger convectiveactivity. Eventually spotting, crown-ing and other indicators of erracticfire behavior develop. Supress such afire as quickly as possible to holddamage to a minimum. With adequateplanning, this situation rarely developswhen underburning, using conven-tional ground-ignition techniques.However, when using aerial ignitiontechniques at the high end of theprescription window, you can ignitetoo much area too quickly. This ac-tion results in severe damage to theoverstory. The behavior of the firstrow or two of spots should warn theburning boss to halt ignition andobserve fire behavior before making adecision to adjust the ignition pattern,change firing techniques, or terminatethe burn.

PREFERRED STABILITY:SLIGHTLY UNSTABLE OR

NEUTRAL

PREFERRED MIXING HEIGHT:1,700 TO 6,500 FEET ABOVE

GROUND

PREFERRED TRANSPORTWINDSPEED:9 TO 20 MPH

Debris BurningStrong convection over cleared

areas burned for site preparation orslash disposal helps vent smoke intothe upper atmosphere. A convectioncolumn will continue to rise until itcools to the temperature of the sur-rounding air or until it reaches thebase of an inversion layer. A well-developed convection column producesstrong indrafts which help confinethis type fire to its prescribed area.Care must be taken to ensure that all

18

burning materials sucked into theconvection column burnout before be-ing blown downwind and dropping tothe ground to act as firebrands.

Whenever a burn site is in hillyterrain, diurnal slope winds must beconsidered. As soon as a slope isheated by the morning sun, anupslope breeze results. This breezewill increase to a maximum (<8 mph)during the early afternoon and end asthe slope cools in the evening. As theslope continues to cool, a downslopewind will develop, reaching a max-i mum (<5 mph) after midnight. Thisbreeze will end after sunup as theslope again begins its daily heatingcycle. If you ignite a tire at the baseof a slope during the day, differentialheating will be greatly increased. Thefire will rapidly spread uphill, givingthe combustion products added lift tohelp vent them into the atmosphere.However the nighttime downslopewind will have the opposite effect,concentrating any drift smoke inlow areas.

Weather is the Vital Element ofPrescribed Burning -- Use the

Weather Forecasts

High fuel moistures produce lots of smoke

Stable conditions or a low mixing height keep smoke near the ground

Unstable conditions and/or a high mixing height provide for rapid smokedispersion 19

Firing TechniquesGeneral

Various firing techniques can beused to accomplish a burn objective.The technique chosen must be corre-lated closely with burning objectives,fuels, topography, and weather factorsto prevent damage to forest resources.The proper technique to use can changeas these factors change. Atmosphericconditions should be favorable forsmoke to rise into the upper air andaway from smoke-sensitive areas suchas highways, airports, and urban areas.

Based on behavior and spread, fireseither move with the wind (headingfire), against the wind (backing fire),or at right angles to the wind (flank-ing fire). The movement of any firecan be described by these terms. Forexample, a spot fire would exhibit allthree types. Heading fire is the mostintense because of its faster spreadrate, wider flaming zone, and longerflames. Backing fire is the least in-tense, having a slow spread rateregardless of windspeed. This type offire has a narrow flaming zone, andshort flames. Flanking fire intensityis intermediate. The slope of the landhas an effect on rate of spread similarto that of wind.

If you encounter slight variationsin fuel volumes or weather condi-tions, consider combining two ormore firing techniques to achieve thedesired result. A solid line of firealways spreads faster and thus buildsup intensity quicker than does aseries of spot ignitions spaced alongthe same line. Intensity increasesabruptly when two fires burntogether. The magnitude of this in-crease is greater when fires convergealong a line rather than along a mov-ing point. The line of crown scorchoften seen paralleling a downwindcontrol line delineates the zone wherea heading fire and a backing firemet.

Residence time is the time it takesthe flaming zone to move past agiven point. The residence time ofheading and backing prescribed firesis often about the same because thedeeper flame depth of a heading fire

compensates for its faster movement.Generally, backing fires consumemore forest floor fuels than doheading fires. The total heat appliedto a site may be roughly equal forboth heading and backing fires, aslong as additional fuels are not in-volved. This result can be expectedeven though the fireline intensity of

the heading fire would be greater. Ina backing fire, the released heatenergy is concentrated closer to theground.

Heading fire may be used with light fuel loadings20

YoungReproduction

Backing fire technique

Backing FireA backing fire is started' along a

baseline (anchor point), such as aroad, plow line, stream or other barrier,and allowed to back into the wind.Variations in windspeed have littleeffect on the rate of spread of a fireburning into the wind. Such firesproceed at a speed of 1 to 3chains per hour. Backing fire is theeasiest and safest type of prescribedfire to use, provided windspeed anddirection are steady. It producesminimum scorch and lends itself touse in heavy fuels and young pinestands.

Major disadvantages are the slowprogress of the fire and the increasedpotential for feeder-root damage withincreased exposure to heat if the lowerlitter is not moist enough. When alarge area is to be burned, it oftenmust be divided into smaller blockswith interior plow lines (usuallyevery 5 to 15 chains). All blocksmust be ignited at about the sameti me to complete the burn in a timelymanner. In-stand winds of 1 to 3 mphat eye level are desirable with back-ing fires. These conditions dissipatethe smoke and prevent heat from ris-ing directly into tree crowns.

When the relative humidity is low,a steady wind is blowing, and fuelsare continuous, an excellent burn canbe anticipated once the fire backsaway from the downwind control line.Under such conditions, however, extracare must be taken to make sure theinitial fire doesn't spot across the line.

Factors Associated with BackingFires:

■ Must be ignited along the down-wind control line.■ Use in heavy roughs.■ Use in young stands (minimumbasal diameter of 3 inches) when airtemperature is below 45°F.■ Normally result in little scorch.■ Costs are relatively high becauseof additional interior plow lines andextended burning period resultingfrom slower movement of the fire.■ Not flexible to changes in winddirection once interior lines areplowed.■ Requires steady in-stand winds(optimum: 1 to 3 mph).■ Will not burn well if actual fine-fuel moisture is above 20 percent.■ Requires good fuel continuity tocarry well.■ A single torch person can pro-gressively ignite lines. 21

Strip-Heading FireIn strip-headfiring, a series of

lines of fire are set progressively up-wind of a firebreak in such a mannerthat no individual line of fire candevelop to a high energy level beforeit reaches either a firebreak oranother line of fire. A backing fire isgenerally used to secure the base lineand the remainder of the area thentreated with strip-heading fires. Stripsare often set 1 to 3 chains apart. Thedistance between ignition lines isdetermined by the desired flamelength. This distance can be variedwithin a fire to adjust for slightchanges in topography, stand density,weather, or the type, amount ordistribution of fuel. Compensationfor minor wind direction changes canhe made by altering the angle of stripfire with the base line. Treat majorchanges in fuel type separately. Aneffective method of reducing fire in-tensity is to use a series of spots orshort 1- to 2-foot-long strips insteadof a solid line of fire. An added ad-vantage of these short strips or spotsis that driptorches will not have tobe filled as often. Strip-heading firespermit quick ignition and burnout,and provide for smoke dispersalunder optimum conditions. However,higher intensities will occur whereverlines of fire burn together, increasingthe likelihood of crown scorch.

Occassionally, on areas with lightand even fuel distribution, a headingfire may be allowed to move over theentire area without stripping to betteraccomplish the objective(s). Thismethod reduces the number of areasof increased fire intensity that occureach time two fires burn together.Caution: Be sure the fire will notescape control. First set a backingfire along the downwind control lineand allow it to burn out.a strip wideenough to control the heading fire.

Factors Associated with Strip-heading Fires■ Secure the downwind base linebefore igniting a heading fire.■ Do not use in heavy roughs. Con-sider alternative techniques if fire-free interval exceeds 3 years.■ Winter use is best because coolweather (below 60°F) helps avoidcrown scorch.■ Use in medium-to-largesawtimber. May be used for annualplantation maintenance burns after in-itial fuel reduction has beenaccomplished.■ Can be used in "flat" fuels such ashardwood leaves.■ Is a good method for brownspotcontrol.■ Because fire movement is fast,large blocks can be burned.■ Can be used with high relativehumidity (50 to 60 percent) and highactual fine-fuel moisture (20 to 25percent).

■ Needs just enough wind to givedirection (1 to 2 mph in-stand).■ Cost is lower than other line-firing techniques because fire pro-gress is rapid and few plow lines arerequired.■ The technique can accommodatewind shifts up to about 45 degrees.■ Flame lengths increase wheneverheading fire converges with a backingfire, thereby increasing the possibilityof crown scorch.■ A single torch person can pro-gressively ignite strips.■ Do not force a burn on a marginalday at the low end of the prescriptionwindow. The fire may burn slowlyuntil after the crew leaves, then pickup intensity and escape.

22

Flanking FireThe flanking-fire technique con-

sists of treating an area with lines offire set directly into the wind. Thelines spread at right angles to thewind. This technique requires con-siderable knowledge of fire behavior,particularly if used by itself. It isused quite often to secure the flanksof a strip-heading fire or backing fireas it progresses. It is sometimes usedto supplement a backing fire in areasof light fuel or under more humidweather conditions. It is useful on asmall area or to facilitate burning alarge area in a relatively short ti me

when a line-heading fire would betoo intense.

This method of firing can standlittle variation in wind direction andrequires expert crew coordination andti ming. For safety, all lines of flankfire should be ignited simultaneouslyand all torch people should keepabreast of one another. If only one ortwo torch people are available, thistechnique is usually altered to set theignition lines 45 degrees into the wind.

In the Piedmont, any ignition linethat drops perpendicularly off a ridgecreates a flanking fire under no-windconditions. If several lines are ignitedoff the end of a ridge or knoll, thepattern looks like a chevron or mapleleaf.

Factors Associated with FlankingFires:■ Always secure downwind base linefirst.■ Fuel loading should be light tomedium—less than 8 tons per acre.■ Wind direction must be steady.■ Best used in medium-to-largesawtimber.■ Allows fast area ignition.■ Needs few control lines.■ In areas with a high understory,multiple torch people are needed andcoordination is very important. Useradio communications whenever torchpeople cannot see one another.■ Useful in securing flanks of otherfire types.

Flanking fire technique23

Point source ignitions

Grid or point source ignition technique

Point Source FiresA prudent burning boss will often

switch from strip-heading fires topoint source fires as the day pro-gresses and continuous lines of firebecome too intense. When properlyexecuted, a grid of spot ignitions willproduce a fire with an intensity muchgreater than that of a line-backingfire but somewhat less than that of aline-heading fire. Timing and spacingof the individual ignition spots arethe keys to the successful applicationof this method. First a line backingfire is ignited across the downwindside of the block and allowed to back10 to 20 feet into the block to increasethe effective width of the control line.A line of spots is then ignited atsome specified distance upwind ofthe backing fire and the process con-tinued until the whole block has beenignited.

To minimize crown scorch,ignition-grid spacing is selected toallow the spots along a line to headinto the rear of the spots along thedownwind line before the flanks ofthe individual spots merge to form acontinuous flame front. The mergerof successive ignition lines thus takesplace along a moving point ratherthan along a whole line at the sametime. Merger along a moving pointcan be ensured by beginning with aclosely spaced square grid (2 chainsby 2 chains is recommended). Closespacing between lines helps the in-dividual spots develop, but ensuresthat the head of one spot will burninto the rear of the downwind spotbefore the heading fire's potentialflame length and intensity are reached.Of course, the closer the spacing, themore merging points you have. Youmust be aware that a large number ofsmall fires burning simutaneously canproduce the same kind of explosiveconvective energy as a single largefire because too much heat energy isreleased too rapidly. This situation isdiscussed more fully under the sec-tion on Aerial Ignition.

Rectangular grids with wider spac-ing between lines than within a lineshould not be used initially becausesuch a pattern may allow the spotsalong a line to merge into a line ofheading fire before running into therear of the downwind spots. Once thefirst few lines have been ignited andfire behavior has been assessed, in-tensity can be regulated to some ex-

tent by changing the time between ig-nition points within a line, thedistance between points, and thedistance between lines. Thus thebalancing act between spacing andti ming has to be continually adjustedas fire behavior reacts to both tem-

poral and spatial changes in fuel andweather.

Intensity is decreased by wideningthe interval between ignition pointsalong a line. If fireline intensity isstill too high after doubling this inter-val while maintaining a 2-chain

24

distance between lines, firing shouldbe halted. Allow the area to burnwith a backing fire or plow it out.Although intensity at the head of anindividual spot is increased by widen-ing the distance between lines, theaverage intensity of the burn as awhole is usually somewhat lower.Check to see that convergence-zoneflame lengths are within tolerableli mits, and that other fire behaviorparameters appear satisfactory. Ifeverything is within prescription, youcan increase both between- andwithin-line distances. This step willreduce ignition time, and decreasethe number of ignitors used. Thenumber of convergence areas withtheir higher intensities will also bedecreased.

Experience to date shows grids upto 4 chains by 4 chains (one ignitionpoint every 1.6 acres) can produceexcellent results. The time needed tocomplete the burn can be reduced byoffsetting successive ignition lines byone half of the within-line spacing.The heading fires from one line willthen come up between the backingfires on the next line.

Factors Associated with PointSource Fires■ Assume much of the area will beburned by heading and flanking firesand very little by backing fires.■ If conditions are ideal for tradi-tional line-backing fires, point sourcefires may be too intense.■ Preferred burning conditions in-clude low (1-2 mph) in-stand wind-speeds. Wind direction can hevariable. Actual fine-fuel moistureshould be above 15 percent.■ When underburning, start with asquare ignition grid (equal distancebetween spots within a line and betweenflight lines). Two chains by 2 chainsis often used.■ Always secure the downwind baseline first.■ Be careful when underburningstands with a flammable understoryor a heavy rough.■ Severe crown scorch is likely iffuel is too dry.■ Under the same weather condi-tions, fires in Piedmont fuel typestend to spread slower and be less in-tense than those in Coastal Plain fueltypes.■ The usual changes in weather dur-ing a typical winter day may requiremodification of ignition patterns

throughout the day. Burn until firesverge on getting "too hot'.' Then eitherquit burning or resort to backingfires only.■ Continually modify the ignitiongrid to take advantage of topographyand changes in understory fuels.■ Costs are low because firing israpid and no interior control linesneed to be constructed.

Aerial IgnitionWhen ground ignition techniques

are used, the downwind spots willusually coalesce and burn out beforethe whole block has been ignited. Incontrast, aerial firing permits ignitionof a block to be completed before thedownwind spots have burned out.This does not present a problem atthe damp end of the prescribed burn-ing window when actual fine-fuelmoisture is near 20 percent. Rapidignition of a block reduces both flyingti me and the time needed to completethe burn. However, when using aerialignition techniques under "traditional"ideal burning conditions for line-backing fires with actual fine-fuelmoisture near 10 percent, rapid igni-tion of the entire area can result in anincrease in fire intensity to unaccep-table levels. You would then havelittle recourse except to let the areaburn out and hope that damage islimited to just a loss in overstorygrowth.

Some experienced burners startfiring early in the day, before the fuelis dry enough to carry fire well.They reduce the distance betweenspots within a line to less than 2chains by 2 chains. The increasednumber of ignitions creates more heatand helps dry the surface fuels,especially when a helitorch is used.The distance between spots must beexpanded as the morning progressesand burning conditions improve.Otherwise, the spots will mergelaterally forming lines of heading firethat get too intense before reachingthe next downwind line of ignitionpoints. The distance between linescan also be increased as necessary tomaintain a square ignition grid.

Current aerial ignition techniquescan be separated into two majortypes: the DAID (Delayed AerialIgnition Device) or ping-pong ballsystem, and the helitorch or flyingdriptorch system. The ping-pong ballsystem utilizes small plastic spheres

containing potassium permanganate.The balls are injected with ethyleneglycol and immediately jettisonedbefore the chemicals react thermallyto produce a flame that consumes theball. The dispensing machine can bemounted in small airplanes orhelicopters. The ping-pong ballsystem works best in continuous fuelsor in areas where a mosaic burn pat-tern is desired.

The helitorch is simply a giantdriptorch and drum of gelled gasolinemounted or slung under a helicopter.The helitorch is well suited fordiscontinuous fuels such as those inclearcuts because this system emits asteady stream of burning fuel globs.It is very difficult to effectivelyregulate the spacing between thesefuel globs. At least one gadget thatapparently solves this problem isbeing marketed. Any helitorch notmodified to effectively control thetiming between the globs of burningfuel should be considered a line-firing device.

Both types of aerial ignitiondramatically reduce the time neededfor an area to burn out. Althoughroughly the same amount of smoke isproduced, it is emitted over a shorterperiod and more of it is entrained inthe convection column. Thus, the im-pact of any adverse air quality effectsis much reduced.

Factors Associated with AerialIgnition■ Rapid firing and burnout allowsuse of a much smaller prescriptionwindow.■ Damp, fine fuels are of criticali mportance. Actual fine-fuelmoistures of 15 to 25 percent arepreferable.■ Requires an experienced burningboss to make ignition grid adjust-ments and to determine when to haltignition due to conditions.■ Although not likely underprescribed fire conditions, too muchheat energy released over too short aperiod will result in a sudden,dangerous increase in fire intensity.■ Large acreages can be safelyburned in a single burning period.

■ Many widely dispersed tracts canbe burned during a single day.■ A contingency plan is essential inthe event the aircraft is reassigned orequipment breaks down duringoperation.

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DAID (Delayed Aerial Ignition Device) dispenser mounted in helicopter

Factors Assoicated with Ping -pongBall (DA ID) System■ Best suited for continuous fuels orwhen a mosaic pattern is desired.■ Ignition spacing within and betweenTight lines can be easily adjusted.■ A 2 by 2 chain to 4 by 4 chaingrid (one ignition point every 0.4acre to one every 1.6 acres) workswell in both palmetto/gallberry andPiedmont fuel types.■ When underburning Coastal Plainfuel types, actual fine-fuel moistureshould be 20 to 25 percent (evenhigher in very heavy fuels) and theair temperature should be low,preferably below 50°F.■ In Piedmont fuel types, actualfine-fuel moisture contents between10 and 15 percent and air temperaturebelow 55°F work well.■ Make sure no DAID's aremistakenly dropped outside the burnas the helicopter turns at the end ofeach line.

Factors Associated with HelitorchSystem■ Not as safe as the DAID system,but less expensive.■ If the torch and fuel tank is slungunder rather than attached to thehelicopter, a larger crew will berequired.■ Creates disposal problems.■ Very difficult to regulate spacingwithin a flight line.■ Fuel-mixing viscosity issometimes inconsistent due totemperature changes which, in turn,further aggravate in-line spacing ofignition spots.■ The most efficient firing techniquefor large, cleared areas with discon-tinuous fuels, including piled or win-drowed debris.■ Use extreme caution when under-burning Coastal Plain fuel types. Tryto keep within-line ignition point in-terval to at least 2 chains.

26

Ignite backing fire first, then center, and then perimeter

Center firing technique

Center and Circular(Ring) Firing

This technique is useful on cut-over areas where a hot fire is neededto reduce or eliminate logging debrisprior to seeding or planting. It worksbest when winds, if any, are light andvariable. This procedure should neverbe used for underburning because ofthe likelihood of severe tree damageas the flame fronts merge

As with other burning techniques,the downwind control line is the firstline to be ignited. Once the base lineis secured, the entire perimeter of thearea is ignited and the flame frontsallowed to converge. One or morespot fires are often ignited near thecenter of the area and allowed todevelop before the perimeter of theblock is ignited. The convectiongenerated by these interior firescreates indrafts that help pull theouter circle of fire toward the center.This tiring method can generally beused in any season, and weather con-ditions are not as critical. However,caution is in order, particularly whenthe atmosphere is unstable. This typeof fire tends to develop a strong con-vection column which can causespotting a considerable distancedownwind.

Pile and WindrowBurning

The objective of piling loggingdebris before burning it is to prolongfire residence time on a restrictedarea so that larger materials haveti me to be consumed. Some areaswill contain an unacceptable amountof large, scattered debris that must beconcentrated to ensure consumption.This material should be piled and notwindrowed. Windrowing can reducesite quality by removing topsoil.Piedmont soils are also susceptible tocompaction from the heavy equip-ment used, especially during wetweather. Full exposure of the soil tothe sun and rain bakes the top layer.Furthermore, the direct force of rain-drops will clog soil pores and oftenresults in erosion on steep slopes.The area beneath the windrows is lostto production because the debris israrely consumed completely and whatremains makes planting difficult orimpossible. Even when windrowscontain breaks spaced every couple ofchains, they still present a barrier tofirefighting equipment and wildlife.

The biggest deterrent to windrowburning, however, is that it causes ahigh percentage of all smoke incidents.Large volumes of fuel, includinglarger pieces that contain a lot ofmoisture, are consumed. However,oxygen for good combustion is lack-ing, especially in large piles and widewindrows. Large amounts of soil areoften mixed in, further compoundingthe problem. The result is a fire thatcontinues to smolder for days orweeks, creating air quality problemsbecause the smoke produced bysmoldering combustion is not hotenough to rise into the atmosphere.The smoke stays near the groundwhere it cools even more, diriftingand concentrating in low areasbecause of cool air drainage. Tomake matters worse, the smoke oftenmixes with humid air to produce fogwhich further reduces visibility.Coupled with these problems is thefact that the weather changes fromday to day making it impossible topredict, and thus manage, the smokefor more than a day or two. For thesereasons, air quality regulations pro-hibit pile and windrow burning in

some areas.Although it generally costs more

to pile than to windrow, piles arepreferable to windrows because accesswithin the area is no problem, plant-ing is easier, burning is safer and,most important, smoke problems aresignificantly reduced since piles burnout much quicker! Generally, pilescontain less dirt and dry faster. Burn-ing piles can easily be "humped" toremove any dirt and pushed in to in-crease consumption. The whole areacan then be utilized.

Keep piles small and minimize theamount of soil in them so surfacewater can pass through, and thedebris can dry quickly. Always pilewhen the ground surface is dry; lesssoil compaction will take place, andconsiderably less soil will end up inthe piles. Allow fresh logging debristo cure first and to dry after rain.Then "shake" the debris while pilingto remove as much soil as possible. Ifmaterial is piled while green or wet,the centers of the piles take an ex-ceedingly long time to dry. Piles thatcontain little soil and are constructedto allow some air movement will

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Tractor-mounted firing device for piled-debris ignition Piles burn more efficiently than windrows

result in a burn that consumessignificantly more of the debris andproduces less smoke. More efficientburning and greater heat output willlift smoke higher, reducing smoke.concentrations near the ground. Burnwhen the atmosphere is neutral toslightly unstable, but not unstableenough to create control problems.

Forest managers can take manysteps to minimize these debris pro-blems. Much of the larger materialleft after harvest is cull hardwood,and periodic use of underburns duringthe rotation will reduce the numberof large hardwoods at harvest. Someof the cull material can often be soldor given away as firewood. Sitesoften can be prepared for seeding orplanting by a broadcast burn withoutpiling the debris. Trees should be cutclose to the ground, leaving lowstumps.

Advances in harvesting equipmentand methods have also helped. Largemobile harvesters chip the wholetree, increasing utilization and reducingthe need for site preparation. Tree-length logging and gate delimbing

(backing a drag-load of trees betweentwo posts) tend to concentrate muchof the debris at the logging deck.Piles created in this manner aregenerally free of soil (providing log-ging was suspended in wet weather)and can be burned as is.

Techniques used in burning pileddebris are somewhat fixed because ofthe character and placement of fuel.Traditionally, each pile is ignitedalong its perimeter, but burnout canbe speeded up considerably by ignitingthe pile center. A helitorch is oftenused because burning globs of gelledgas penetrate deep into piled fuelsand provide a "large" heat source.Tractor-mounted ignition devices thathelp burning fuel penetrate downtoward the center of a pile have alsobeen fabricated.

Factors Associated with Pile andWindrow Burning:■ A large majority of all smoke-related incidents are caused by thistype of burning.■ Produces the most smoke of allfiring techniques.

■ Burns can continue to smolder formany weeks.■ Smoke produced at night tends tostay near the ground.■ Cannot be readily extinguishedafter ignition. If extinguished, evenmore effort is required to reignitethem the next day.■ Can burn in light or variablewinds.■ Usually safe and easy to control,provided piles are not next to theedge of the area and are not left unat-tended, particularly when burningduring periods of high fire danger.■ Piles should be as free of soil aspossible.■ Fuel should be dry.■ Burn area should be as small aseconomically practical.■ Need neutral to unstable condi-tions for good smoke dispersion —which generally do not occur aftersunset.■ Need good mixing heights andtransport winds.

Dirt in windrows can aggravate smoke managementproblems

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Windrows can smolder for long periods of time

SmokeManagement

Prescribed burning helps achievemany desired resource objectives, butit nevertheless pollutes the air. Wetherefore have an obligation to mini-mize adverse environmental effects. Ifthis obligation is disregarded, pre-scribed burners can be held liable fordamages from accidents or problemsresulting from their actions. Use thefollowing guidelines to reduce thei mpact from smoke.

A. Define objectives. — Be sure youhave clear resource objectives andhave considered both on-site and off-site environmental impacts.B. Obtain and use weather andsmoke management forecasts.

Iweather and smoke managementforecasts are available to all resourcemanagers through State forestryagencies. Be sure to use them. Suchinformation is needed to predictsmoke generation and movement as

well as fire behavior. If the forestryweather outlook does not agreereasonably well with the radio/TVforecast, find out why.C. Don't burn during pollutionalerts or stagnant conditions.—Smoke will tend to stay near theground and will not disperse readily.Many fire-weather forecasters includethis in their regular forecasts.D. Comply with air pollution controlregulations. — Know the regulationsthat apply at the proposed burn sitewhen you make the prescription.Check with your State fire controlagency.E. Burn when conditions are good

for rapid dispersion.— Ideally, theatmosphere should be thermallyneutral to slightly unstable so smokewill rise and dissipate, but not sounstable as to cause a control prob-lem. Again, your local forestry agencycan help. Some States use CategoryDay based on the ventilation rate, but

if the Dispersion Index is calculatedfor your area, it is a better indicator(see table 1). Reassess a decision toburn when the daytime DispersionIndex value is below 41.F. Use caution when near or upwindof smoke-sensitive areas. — Burningshould be done when wind will carrysmoke away from public roads, air-ports, and populated areas. Do notburn if a smoke-sensitive area iswithin 1/2 mile downwind of the pro-posed burn.G. Use caution when smoke-sensitive areas are down drainage.

smoke. Use aggressive mopup asnecessary.

Prescribed Fire Reduces A irPollution From Wildfires

TABLE 1.—Relationship of Dispersion Index toOn-the-Ground Burning Conditions

Dispersion

Index

>100

61 - 100

41 - 60

21 - 40

13 - 20

7-12

1 - 6

Burning conditions

Very good — Burning conditions may be so good that fires may behazardous and present fire control problems. Reassess decision to burn.

Good — preferred range for prescription burns.

Generally OK — climatological afternoon values in most inland forestedareas fall in this range.

Fair — stagnation may be indicated if accompanied by low windspeeds.Reassess decision to burn.

Generally poor — do not burn. Stagnant if persistent, although better thanaverage for a night value.

Poor — do not burn. Stagnant during the day, but near or above average atnight.

Very poor — represents the majority of nights at many locations.

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nighttime smoke patrol is oftennecessary.P.Anticipate down-drainage smokeflow.—Atmospheric conditions tend tobecome stable at night. Stable condi-tions tend to keep smoke near theground. In addition, downslope windsgenerally prevail at night. Thus, smokewill flow down drainage and concen-trate in low areas. When relativehumidity rises above 80 percent andsmoke is present, the formation offog becomes increasingly likely asmoisture condenses on the smokeparticles. There seldom are satisfac-tory solutions to these problems, sothey should be avoided entirelywhenever possible.Q. Mopup along roads. — Start mopupalong roads as soon as possible toreduce impact on visibility. Ex-tinguish all stumps, snags and logs.Mopup should be particularly ag-gressive whenever roads are in areaswhere smoke could travel downslopeor up or down a drainage.R. Have an emergency plan. — Beprepared to extinguish a prescribedburn if it is not burning according toplan or if weather conditions change.Have warning signs available. If winddirection changes, be prepared toquickly contact the local law enforce-ment agency and to direct traffic onaffected roads until traffic controlpersonnel arrive.

Caution: Check For DownDrainage Smoke Flow At Night!

Screening System forManaging Smoke

Most southern States have eithervoluntary or mandatory smokemanagement guidelines that shouldbe followed when planning a pre-scribed burn. Your local State forestryoffice can advise you of recommendedor required procedures. Many ofthese guidelines use a term called theventilation rate or ventilation factorwhich estimates the atmosphere'scapacity to disperse smoke. Anotherway to estimate this capacity is to usethe Dispersion Index (see table 1)developed at the Southern Forest FireLaboratory. This calculated index isbetter able to incorporate diurnalchanges in the lower atmosphere.

If you will be burning in a Statethat has not issued guidelines, use theSouthern Forestry Smoke ManagementGuidebook (see Suggested Readingsection, second listing under U.S.Department of Agriculture). Thisguidebook tells you how to predictsmoke concentrations at any distancedownwind. An improved and com-puterized version, called PRESMOK,simplifies use of this predictionsystem. Copies are available from theSouthern Forest Fire Laboratory. Useof this smoke screening system doesnot take precedence over Stateguidelines. The full system cannot bediscussed here, but an updated versionof the Initial Screening System basedon the Guidebook is presented below.This system has five steps: (1) Plotdirection of the smoke plume, (2)Identify smoke-sensitive areas, (3)Identify critical smoke-sensitiveareas, (4) Determine fuel type, and(5) Minimize risk.

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Step 1. Plot Direction of the SmokePlumeA. Use maps on which the locations of

smoke-sensitive areas can be iden-tified. Plot the anticipated down-wind smoke movement a distanceof: 5 miles for grass fuelsregardless of fire type; 10 milesfor palmetto-gallberry fuels whenusing line-backing fires or spotfires; 20 miles for palmetto-gallberry fuels using line-headingfires; 30 miles for all loggingdebris fires; 5 miles for line back-ing fires in all other fuel types;and 10 miles for line-heading firesin all other fuel types, or burns of250 acres or more. First locatethe planned burn area on a mapand draw a line representing thecenterline of the path of thesmoke plume (direction oftransport wind) for the distanceindicated. If the burn will last 3or more hours, draw another lineshowing predicted wind directionat completion of the burn.

B. To allow for horizontal dispersionof smoke as well as shifts in winddirection, draw two other linesfrom the fire at an angle of 30degrees from the centerline(s) ofobserved wind direction (45degrees if forecast wind directionused). If tire is represented as aspot, draw as in figure A. Iflarger, draw as in figure B. Theresult is your probable daytimesmoke impact area.

C. Now go down-drainage for one-half the distance determinedabove, but do not spread out exceptto cover any valleys or bottoms.The result is your probable night-time impact area, providing theburn will be completed at least 3hours before sunset, and providingthe forecast night winds are lightand variable.

Step 2. Identify Smoke-SensitiveAreas

Identify and mark any smoke-sensitive areas (such as airports,highways, communities, recreationareas, schools, hospitals, and factories)within the impact zone plotted in step 1.These areas are potential targets forsmoke from your burn.A. If no potential targets are found,

you may burn as prescribed.B. If the area to be burned contains

organic soils that are likely toignite, do not burn.

C. If any targets are found, continuethis screening system.

Step 3. Identify Critical Smoke-Sensitive AreasA. Critical smoke-sensitive areas are:

1.Those that already have an airpollution or visibility problem.

2. Those within the probablesmoke impact area as determinedbelow. If the distance determinedin step 1 was:

a) 5 miles, any smoke-sensitivearea within 1/2 mile is critical,both downwind and down-drainage.

b) 10 miles, any smoke-sensitivearea within 1 mile is critical.

c) 20 miles, any smoke-sensitivearea within 2 miles is critical.

d) 30 miles, any smoke-sensitivearea within 3 miles is critical.

B. If any critical smoke-sensitiveareas are located, DO NOTBURN under present prescription!

1.Prescribe a new wind directionthat will avoid such targets andTeturn to the beginning of thisscreening system, or

2. If smoke-sensitive area is in lasthalf of distance criteria, reduce

the size of the area to be burn-ed by approximately one half,complete burn at least 3 hoursbefore sunset, and aggressivelymopup and monitor, or

3. Use an alternative other thanburning.

C. If no critical smoke-sensitive areasare found, or criteria B1 or B2 ismet, continue the screening system.

Step 4. Determine Fuel TypeThe smoke produced may vary

greatly by type, amount, and condi-tion of fuel consumed.A. From the list below determine

which broad type best fits yourfuel.I. Grass (with pine overstory)2. Light brush3. Pine needle litter4. Palemetto-gallberry5. Windrowed logging debris6. Scattered logging debris or

small dry piles

B. Review fuel categories orcombinations.1. If the fuel type is described by

one of the above categories,continue.

2. If your fuel type is not com-parable to any of the above,pick the fuel type for whichfire behavior and smoke pro-duction most nearly comparewith yours and proceed withEXTREME CAUTION on thefirst few burns.

C. If the fuel type is windrowed log-ging debris, and you have identi-fied smoke-sensitive areas, DONOT BURN under presentprescription. Smoke production isgreat and can last for weeks.

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1.Prescribe a new wind directionto avoid all smoke-sensitiveareas and return to the beginningof the system.

2. If you cannot avoid all smoke-sensitive areas, you will need abetter procedure than this sim-ple screening system. Refer tothe Southern Forestry SmokeManagement Guidebook oruse PRESMOK.

D. If the fuel type is scattered log-ging debris or small, essentiallydirt-free, dry piles, the followingconditions should be met:1. Size of area to burn less than

100 acres.2. No major highways within 5

miles down drainage.3. No other smoke-sensitive areas

within 3 miles down drainage.4. If relative humidity is predicted

to stay below 80 percent andsurface winds above 4 m.p.h.all night, the distances in 2 and3 above can be cut in half.

E. If your comparable fuel type isone listed in 4A above, determineyour total per-acre fuel loading.See below or Southern ForestrySmoke Management Guidebookfor tables to assist you.1. If less than 10 tons per acre,

continue. Generally, the total

fuel loading will be less than10 tons in the fuel types listedbelow when age of rough is:a. Grass (with pine overstory),

any age. Also wheat fieldsand other agricultural burns.

b. Light brush, 7 years old orless (10 years if basal area isunder 100 square feet peracre).

c. Loblolly pine witha. palmetto-gallberry

understory, 7 years or lessif basal area is under 150square feet per acre.

b. little or no understory, 15years or less if basal areais under 150 square feetper acre.

d. Slash pine witha. palmetto-gallberry

understory, 5 years or lessif basal area is under 150square feet per acre.

b. little or no understory, 8years or less if basal areais under 150 square feetper acre.

2. If greater than 10 tons per acre,refer to the Southern ForestrySmoke ManagementGuidebook or double thedistance determined in step IA.Use 1 1/2 times the distance ifclose to 10 tons.

Step 5. Minimize RiskTo meet your smoke management

obligations when any smoke-sensitivearea may be affected by your burn,you must meet all of the followingcriteria to minimize any possibleadverse effects.

■ Height of mixing layer (mixingheight) is 1,650 feet (500 meters)or greater.

■ Transport windspeed is 9 mph (4meters per second) or greater.

■ Background visibility is at least 5miles within the plotted area.

■ If rough is older than 2 years, usea backing fire. If burn can becompleted 3 hours before sunset,or if no smoke-sensitive areas arelocated in the first half of theimpact area, other firing techni-ques can be used.

■ Promptly mopup and monitor tominimize smoke hazards.

■ If a smoke-sensitive area is in theoverlapping trajectory of twosmoke plumes, it should be 1 milefrom either source (2 miles if oneis from logging debris).

■ For night burns, backing fireswith surface windspeed greaterthan 4 mph and relative humidityunder 80 percent should beprescribed.

■ If it appears that stumps, snags,or logs may cause a residualsmoke problem, take steps to keepthem from burning. If they doignite, extinguish them.

■ Daytime value of the DispersionIndex between 41 and 60 is ade-quate for small fires and low levelsof burning activity. As either sizeof individual fires or level of burningactivity increases, the DispersionIndex value should also increase.

Many variables affect the behaviorand resulting smoke from a prescribedburn. The above system works best inflat terrain and was not designed foruse in mountainous country. It doesnot attempt to consider all the variables:it can only offer broad guidelines. Ifyour prescribed fire complies with allconditions in these five steps, youshould be able to safely burn withoutcausing a smoke problem. If youhave any marginal answers, areas thatare especially sensitive to smoke,heavy fuel loadings or wet fuels, usethe prediction system mentioned inthe Southern Forestry SmokeManagement Guidebook. You mustmake the final judgement.

CAUTION: Be Sure AtmosphericConditions Are Conducive

To Good Dispersion!

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Planning thePrescribed Burn

The first step to a successfulprescribed burn is a stand-by-standanalysis of your forest lands. Deter-mine the needs of each stand and whatacitons should be taken to meet theseneeds. Prescribed fire as well as otheralternatives should be addressed hereand a decision reached regarding thepreferred treatment.

Prescription burning is a highlytechnical job requiring knowledge oftire behavior, suppression techniques,and environmental effects of fire.Well in advance of the burning season,scout stands that may need a firetreatment and choose those to burn.Overplan the number of acres to beburned by 10 to 25 percent so substi-tutions can be made if necessary, andso additional areas can be burned iffavorable weather continues. Thenumber of suitable burning daysvaries widely from year to year andthe acreage that can be burned on a

given day can be increased drama-tically if aerial ignition is used. Ifyou have several blocks to burn, setpriorities. Specifically designate anyplanned burns that require exactingweather conditions. Considerationsinclude heavy fuels, small trees,potential smoke problems, etc. Indi-cate all blocks to be burned on anadministrative map. When the burnsare completed, record the dates onthe map.

A written prescribed-burning planprepared by a knowledgeable personis needed for each area to be burned.Complete the plan before the burningseason and be prepared to burn whenthe prescribed weather occurs. Someplans may be quite short and simplewhile others will be complex. Indivi-dual blocks can vary from a fewacres to over 1,000, but topography,and amount and type of fuel in a unitshould be similar. Your plan can con-

sist of a series of blocks in the samecompartment or management unit aslong as the same objectives apply andthe fuel is similar.

Break large areas into 1-day burningblocks or smaller areas. Use existingharriers such as roads and creeks aspossible, but be sure these barriersare effective at the time of the burn.

The Written PlanA prepared form with space for all

needed information is best. The formwill serve as a checklist to be sureyou have not overlooked some aspector potential impact. Sample forms forboth understory burns and postharvestburns can be found on pages 34, 35,and 36. The "simple" form can beused on small burns within a largelandholding that does not containpublic roadways. Contents of the writ-ten plan should include:

TABLE 3 — Effects of Age of Rough on Some Common Fire Parameters

Assume a 20-year-old southern pine plantation on the Coastal Plain with no understory present. Table values will increase as theamount of understory increases. In the Piedmont and mountains, an understory is likely to have an opposite effect ekcept duringsevere drought.

= Backing fire with rate-of-spread of 100 feet per hour and fuel consumption of 60 percent.11-1 = Heading fire with rate-of-spread of 660 feet per hour and fuel consumption of 40 percent.

'Ambient temperature of 50°F and windspeed of 2mph. Lower temperatures and higher windspeeds will decrease scorch height.

33

Equipment and PersonnelList equipment and personnel needed

on site and on standby. Assign duties.

Fire PrescriptionThe amount of fuel, weather condi-

tions and desired intensity of the burnwill determine the firing technique

and ignition pattern to use. Speciesinvolved and height of overstory willdetermine the maximum intensity thatcan be tolerated. Where large amountsof fuel arc present, cooler burns canbe accomplished by burning whenhumidity and fuel moisture are nearthe high end of the range so a smaller

fraction of the fuel will burn. Lowertemperatures are desireable with moreintense fires, especially when under-story fuels are tall.

A series of user-friendly computerprograms called BEHAVE has beendeveloped to predict the behavior of afire. They are based on a specific set

Required SignaturesProvide spaces for signature(s) of

person(s) who prepared the plan. Thisidentifies the people who know the mostabout the plan.

Purpose and Objective(s)Include in the written plan the

reason(s) for prescribing a fire.Examples include: prepare seedbed,control insects or disease, reducehazard, improve wildlife habitat, con-trol understory, improve forage,increase accessibility, and enhanceaesthetics. In addition, give a specificquantifiable objective. State exactlywhat the fire is to do — what itshould kill or consume, how muchlitter should be left, etc. Also con-cisely describe the expected firebehavior, including the desired rangein flame length and fireline intensity.In case prescribed weather conditionsdo not materialize, this descriptionmay allow the objective(s) to still beachieved by varying the firing tech-nique. Such information will also beuseful in determining success of aburn.

Map of the Burning UnitA detailed map of each burning

unit is an important part of the burningplan. The map should show the boun-daries of the planned burn, adjacentland owners, topography, control lines(both existing and those to construct),anticipated direction of the smokeplume, smoke-sensitive areas, holdingdetails, and other essential informa-tion. Plowed control lines are oftennot necessary. Consider expanding theplanned burn to employ existing fire-breaks and natural barriers. For exam-ple, use fuel type boundaries such asoccur near creek bottoms where thefire will go out as it encounters fuelswith a higher moisture content. Showareas that should be excluded or pro-tected such as improvements, youngreproduction, sawdust piles, etc. Sub-divide each area to be burned intological, I-day burning blocks, orsmaller areas if smoke managementneeds dictate.

37

of fuel data and prescribed weatherconditions. These programs will runon a hand-held calculator with a firebehavior CROM (Custom Read OnlyMemory). You can use them in thefield to make instant decisions asburning conditions change. A versioncalled MICRO BEHAVE, compatiblewith IBM PCs, is also available atvery low cost from Forest ResourcesSystems Institute (FORS), CourtviewTowers, Suite 24, 201 N. Pine Street,Florence, AL 35630; telephone (205)767-0250.

Always think about smokemanagement. Make sure your burningplan passes a smoke managementsystem.

SeasonWinter — Most understory burning

is done during the winter dormantseason. Acceptable relative humidity,temperature, fuel moisture, and steady,persistent winds most often occurthen.

Spring — More variable weatherand generally higher fire danger dic-tate smaller burns in the spring.Check with local wildlife specialists toavoid periods when prescribed burningcould harm nesting wildlife. Pinebuds are more exposed and thus moresusceptible to heat damage duringelongation.

Summer — Hot weather during thesummer means much less heat isneeded to raise the temperature ofplant tissue to lethal levels. For thisreason, summer burns are used to killundesirable hardwoods — usually aseries of burns after an initial winterburn. Care must be taken not toseverely scorch overstory crowns.Postharvest burns to dispose of log-ging debris can be conducted year-round, but conditions are especiallygood in mid to late summer becausethe high ambient temperatures helpdry out the larger materials.

Fall — Exercise special care whenburning in early fall just prior to thedormant season. Both loblolly andslash pines are more likely to die ifseverely scorched or root damaged atthis time.

Time of DayNormally, plan burning operations

so the entire job can be completedwithin a standard workday. Prescribedfires usually are ignited between 10a.m. and noon, after sunshine hasevaporated any early morning dew. Ifan inversion occurred the previousnight, wait until daytime heatingeliminates it before igniting the fire. Ifthe forecast is for poor nighttimedispersion, halt ground ignition before3 p.m. standard time (ST). Halt aerialignition before 4 p.m. ST, to allowadequate time for the fire to burn outbefore atmospheric dispersion condi-tions deteriorate.

Burning conditions are usually bet-ter during the day than at night becausewindspeed is higher and wind direc-tion steadier. Smoke management isalso much easier during the day. Atnight smoke tends to stay close to theground and collect in depressions.Also, relative humidity usually in-creases at night, resulting in spottyburning and an increased likelihoodthat fog will form.

However, on winter nights when astrong cold front moves across anarea, winds remain strong and persis-tent and relative humidity does notrise greatly. These conditions can pro-vide good prescribed burning weather,especially when cooler temperaturesare needed. Whenever night burningis done, keep a close check on wind,humidity, and smoke drift.

Firing PlanKey parts of a successful prescribed

burn are plans for firing and holdinga burn. This plan should consist of anarrative section and a detailed map.The burning unit map is ideal for thispurpose because it already containsmuch pertinent information. Add thefollowing items:■ Firing technique, ignition pattern,

and planned ignition time.■ Manpower and equipment

needed, and planned distributionfor setting, holding, patrolling,and mopping up the fire andmanaging the smoke.

■ Location and number of reinforce-ments and equipment that can bemobilized rapidly if fire escapes.

■ Instructions for all supervisorypersonnel, including completedescription or illustration ofassignment, and forces needed tofire out, hold, and mopup thefire.

Alternative PrescriptionsConsider alternative sets of weather

conditions (wind, relative humidity,and/or fuel moisture) and methods ofburning that will produce a fire ofabout the same intensity and accomplishthe desired objectives. Two separateburns may be necessary to eliminateheavy volumes of fuel without damageto the overstory.

Preparation Work and Protection ofSensitive Features

Include fire lines to be constructed,snags to be lined or felled, specialfeatures to be protected and the instal-lation of any monitoring equipment.Give instructions for the protection ofsensitive areas. Consider historicaland archeological sites, streams,habitats of threatened and endangeredspecies, and fragile soils.

Notification of Intent to BurnList the names and telephone numbers

of the local State fire protection officerand other officials who should becontacted prior to the burn. Makedirect contact with all homes andbusinesses in the area likely to bei mpacted by the burn. Offer toevacuate anyone with respiratory prob-lems during the burn. Put them up ina local motel if necessary. Considerwritten notification explaining thereasons for the burn and encouragingindividuals with respiratory ailmentsto contact you — include a 24 hourtelephone number. Establish respon-sibility for burn-day contacts and howthey will be made. Consider a news-paper article describing the reasonsfor the burn if you expect to producelots of smoke or anticipate anynegative reactions.

Establish Burn Acreage GoalsBut NOT Quotas!

38

Impact of SmokeList any sensitive areas near to,

downwind, or down drainage of theburn. Include smoke managementstrategies of avoidance, emissionreduction, dispersal, or all three, tominimize any adverse smoke impacts.Attach the smoke management plan(e.g. screening system calculations) aspart of the burning plan.

Legal RequirementsList any legal requirements that might

apply, and what the prescribed burnermust do to comply. Remember, theperson who conducts the prescribedburning operation may not be the onewho made the analysis and preparedthe prescription. Follow all applicablestatutes, regulations, and agency pro-cedures. Needs for a written prescribedburning plan, documentation of devia-tions from the plan, and good judge-ment cannot be overemphasized. Er-roneous forecasts, unforeseen localinfluences, and accidents occur despiteour best efforts to prevent them. Pro-per documentation will help establishthat the prescribed fire was conductedin a prudent and professional manner.If a prescribed fire results in damageor bodily harm and you cut corners,neglected any mandatory require-ments, or acted with disregard to thewelfare of others, you are likely to beheld responsible, regardless of whethercompliance would have changed theoutcome. For more information seethe summary article, Legal Implica-tions of Prescribed Burning in theSouth by William C. Seigal, listed inthe Suggested Reading section.

Escaped-Fire PlanIdentify potential fire escapes and

specify actions to take should suchoccur. Designate who will be incharge of suppression action and whatpersonnel and equipment will beavailable.

Control and MopupA plan must include necessary

safeguards to confine the fire to theprescribed area and reduce smokeimpact. Mopup promptly and com-pletely. Emphasize protection of alladjacent land. Consider and makeplans for any variation in forecastedweather that may change a prescribedfire into a damaging wildfire, increasethe pollution in smoke-sensitive areas,or create visibility problems on adja-cent roads.

EvaluationInclude space for a written evalua-

tion of the prescribed burn. A recordof actual weather conditions, behaviorof the fire, and total environmentaleffects of the burn is essential. Thisinformation is used to determine theeffectiveness of the prescribed burnand in setting criteria for future burns.

At the beginning of the prescribedburn, record windspeed and direction,fuel moisture, humidity, burning in-dex, temperature, days since andamount of last rain, and dampness ofsoil and lower litter. Also record firebehavior data such as type of fireused, length of flames, and forwardrate of spread. Continue to recordapplicable weather and fire-behaviorparameters at 2- to 3-hour intervalsthroughout the burn. After the burn,record amount of crown scorch, con-sumption of brush, litter, and duff,and any other evidence of fire intensitysuch as unburned areas, exposedmineral soil, and cracks in bark orcupping on the lower bole due to barkconsumption. Also include a shortnarrative on success of the burn.

Give Prescribed Burning FIRSTPriority When Weather Conditions

Are Favorable

Prescribed Fires Often BehaveErratically A t Edges Of Openings

39

Establishing a control line in heavy rough

Steps to Be ConsideredGood preparation is the key to

successful burning. It is essential inrealizing maximum net benefits atacceptable cost. Preparation consistsof all steps necessary in making thearea ready for firing and of having allneeded tools and equipment in operatingorder and ready to go.

This preburn work is often doneby a crew consisting of a leader, atractor operator, and a cleanup per-son. The leader should be trainedand experienced in prescribed fire.The job is to locate and establishcontrol lines to best accomplish theobjectives of the burning plan. To dothis job skillfully, the leader musthave personal knowledge or informa-tion available about:■ Weather elements involved■ Fire behavior■ Smoke management■ Amount and type of fuel on thearea■ Location of natural and manmadefire barriers■ Degree of risk and hazard present■ Burning technique and intensity offire to be used■ Burning objectives for the par-ticular area■ Restrictive measures dictated bylaw or local custom■ Fire suppression safety■ Location of any improvementswhich could he endangered■ Areas within the prescribed unitthat may need to be excluded fromfire, such as:

— areas with extreme mopup orbreakover potential (sawdustpiles, snags, etc.)highly scenic areas

— highly erodible areas— streamside zones— areas harboring special-quality

wildlife or plant communityhabitat that would be damagedby fire

— desirable hardwood areastimber and grass areas sus-ceptible to fire damage

All site-specific informationshould be included in the writtenprescription. Before starting work,the leader should inspect the area bywalking over it and should give safetyinstructions to the crew.

Establishing ControlLines■ Plow in advance of burning,preferably after leaf fall, to reduceeffect of fallen material on preparedlines.■ Use natural barriers such asstreams, logging roads, or cultivatedfields whenever possible.■ Hold plowlines to a minimum,keeping them shallow and on the con-tour as much as possible in hillycountry. Consider igniting from wetlines. Use skid trails and loggingroads where feasible.■ Keep control lines as straight aspossible. Bend them around excludedareas, avoiding abrupt changes indirection.■ Avoid rock outcrops and boggyground.■ Double or widen plow lines athazardous places.

■ Subdivide large areas into logicalI-day burning jobs.■ Avoid leaving dense timber standsor heavy fuel pockets near lines.

After Plow Lines areEstablished■ Remove any material above theline that could carry fire across thecontrol line such as vines andoverhanging brush.■ Fall snags near line (inside andoutside).■ Construct water bars and leadoffditches in steeper terrain to preventsoil erosion.■ Seed and fertilize exposed soil onplow lines in steep topography to pre-vent soil erosion.

Burning-unit Map■ Locate all control lines on the mapnoting any changes from the originalplan.■ Note on the map any danger spotsalong control lines having potential forfire escape.

41

Post smoke warning signs

42

Check fuel moisture of duff and litter

Executing the BurnThere are few days of good

prescribed burning weather duringthe year. When these days arrive,give top priority to burning. Withadequate preparation, burning canbegin without loss of opportunity.

A prescribed burning crew con-sisting of a burning boss and 3 to 6crew members can handle a burn ofseveral hundred acres. The leadershould be an experienced prescribedburner with an understanding of firebehavior. Such a crew often consistsof 3 torch people equipped with handtools, and a tractor operator with aplow unit for emergency use. If aerialignition is used, the ground crewoften consists of a tractor-plow unitand a 2-person crew with 2 pickups.The aerial crew generally consists ofa pilot and machine operator whenthe ping-pong ball system is used. Ifthe pilot is not an experienced firebehavior observer, the burning bossshould also be in the helicopter (asallowed) where he/she will have arelatively unobstructed view of thedeveloping fire. Use of the helitorchcan require 2 to 3 additional groundsupport people to mix the fuel andposition the drums depending upontorch configuration and company/agency policy. Disposal of any unusedhelitorch fuel mix can present additionallogistical problems; alumagel is toxicand should never just be dumped.

Radios for communication areessential for aerial ignition and forany large burn. Behavior of aprescribed burn will vary because ofroads or other openings in the timberstand, varying fuel conditions, chang-ing weather, and the firing techniqueused. Two vehicles are essential topermit maximum mobility of theburning boss and crews. Chain sawsare useful additions to the equipmentsupply.

The burning boss should have thecrew ready to fire the area as early inthe day as conditions permit, leavin

maximum time for rnopup and patrolof the lines. Normally, plan to com-plete any one job within a standardworkday. The burning boss mustmake sure the crew has the properclothing and safety equipment and isin good physical shape. Properclothing includes long-sleeve fireresistant or cotton shirts, pantswithout cuffs, leather boots with non-skid soles, safety glasses, hardhat,gloves, and plenty of drinking water.During the summer, the possibility ofheat exhaustion and heat stroke mustbe considered.

Examples of prescribed burning equipment

Small test fire to check behavior of fire and smoke

Prompt mopup will minimize residual smoke

Checklist■ Make sure all equipment is inworking order and safe to use.■ Carry burning plans and maps tothe job.■ Check the weather before startingto burn and keep updated throughoutthe day.■ Check all control lines, clean outneedles and leaves, and reinforce asnecessary.■ Notify adjoining property ownersand local fire control organizationsbefore starting fire.

■ Instruct crew on procedures, in-cluding safety precautions and theproper operation of equipment anduse of hand tools.■ Post signs on public roads and beprepared to control traffic if potentialexists for smoke to reduce visibility.■ Check duff and soil for dampness.■ Test burn with a small fire beforefiring; check the fire and smokebehavior to make sure the fire isburning as expected. If it is not,decide whether the observed behavioris acceptable. This is the time to

cancel the burn if you are not com-fortable with the observed behavior.■ Inform crew of starting point andfiring sequence. Give each member amap.■ Have a means of instant com-munication with all crew members.Portable radios are very useful.■ Be alert to changing conditions,and be prepared to change burningtechniques or plow the fire out if anemergency arises.■ Burn so the wind will carrysmoke away from sensitive areas.■ Mopup and patrol perimeters con-stantly during the operation, andthereafter until there is no furtherdanger of fire escape or smokeproblems.

"Give Prescribed BurningTOP PRIORITY

When Burning Weather Arrives"

Evaluating theBurn

The purposes of a burn evaluationare to determine how well the statedobjectives of the burn were met andto gain information to be used infuture burns. An initial evaluationshould be made immediately after theburn, perhaps the following morning.A second evaluation should be madeduring or after the first postfiregrowing season.

Points to be Considered■ Was preburn preparation properlydone?■ Were objectives met?■ Was burning plan adhered to?Were changes documented?■ Were weather conditions, fuelconditions, fire behavior, and smokedispersion within planned limits?■ What were effects on soil, air,vegetation, water, and wildlife?■ Was fire confined to intendedarea; any escapes?■ Was burning technique correct?■ Were costs commensurate withbenefits derived?■ How can similar burns bei mproved?

I ndications and

Guidelines

Needle ScorchThe best indicator of crop tree

damage is percent foliage discolora-tion. Assuming that buds and branch-lets are not heat-killed, even crownscorch approaching 100 percentgenerally will not kill trees unlesssecondary factors such as insectattack or drought materialize. If,however, loblolly pine stands areburned in the fall (September orOctober), after the trees haveundergone their last needle flush ofthe growing season but prior to theonset of dormancy, research indicatesthat 100 percent crown scorch is like-ly to kill them. Slash pine appears tobe more tolerant of severe crownscorch during the fall.

If more than 15 percent of a southernpine tree's needles are actually con-sumed by flames, the tree's chancesof survival would be poor even ifvery little of the rest of the crown isscorched. Young vigorous trees aremore likely to survive severe crowndamage than are older individuals.

Magnitude and duration of growthresponses in southern pines due tovarious levels and seasons of defolia-tion are not well documented. Bothnegative and positive responses havebeen observed, but the preponderanceof evidence shows a direct relation-ship between diameter and heightgrowth loss and crown scorch.

Providing no crown consumptiontook place, the following table willhelp in estimating potential growthloss in loblolly and slash pines over3 inches dbh. These "ball park"estimates can be used for othersouthern pines as well, until morespecific results become available.

A good indicator of hardwoodcontrol is a series of bark cracksextending into the cambium near groundlevel. This indicates sufficient heatwas applied to penetrate the bark andkill the cambium. Although large hard-woods can be damaged by periodicfires they are difficult to kill.

Judge the success of burning forbrownspot control by the number oflongleaf seedlings with all infected

needles burned off, but still having aprotective sheath of green needlesaround the unharmed terminal bud.

Soil and Root DamageBurning under prescribed conditions

in the South generally does not exposebare soil. If duff remains after aburn, the physical properties of thesoil probably were not harmed. Ifmineral soil is exposed, especially onsteep slopes, soil movement anddeterioration of site quality may occur.

Root damage is likely wheneverthe organic layer is completely con-sumed. It should also be expectedwhenever burns are conducted overdry soils (drought conditions) orwhen a deep litter layer is present,even though some duff remains. Newroot growth in vigorously growingpines can usually offset these losses,but older trees, having survived suchfires without crown damage, often diesix months to a year later for noapparent reason.

Air QualitySmoke behavior must be continually

evaluated from the time the fire isignited until smoldering ceases.Unusual or unexpected smoke effectsshould be noted and correlated withother parameters of the burn for futureuse. Any public complaints should berecorded as part of the evaluation.

Percent Damage

Crown Scorch

0 to 33 Some volume growth loss may occur the firstpostfire growing season but it will be minor.

34 to 66 Volume growth loss usually less than 40 percentand confined to first postfire growing season.

67 to 100 Reduction may be as high as a full year'svolume growth spread over 3 years.

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Timing and Points toEvaluate

Evaluation should take placei mmediately after the burn and againduring the first posture growingseason. In the case of late summerprescribed tires, the second evalua-tion should take place the followingspring after the next growing seasonhas begun.

Points in First Evaluation■ Amount of overstory foliagediscoloration.■ Amount of consumption and top-kill of understory vegetation.■ Consumption of infected needleson longleaf seedlings without injuryto terminal bud.■ Amount of litter remaining onforest floor.■ Smoke dispersion into upperatmosphere and success in avoidingsmoke-sensitive areas.■ Protection of areas not to beburned.■ Any escape of fire.■ Any adverse public comment orreaction prior to, during, ori mmediately after the burn.

Points in Future EvaluationFuture evaluation can best be

made after the start of the growingseason to determine the following:■ Resin exuding from pine trees, anindicator of cambium damage orinsect attack.■ Other signs of beetle attack.■ Mortality of timber or otherdesirable vegetation.■ Sprouting vigor of undesiredvegetation.■ Recovery of longleaf seedlingsfree of brownspot.■ Remaining duff layer, mineral soilexposed, and any soil movement.■ Public expression for or againstthe burning program.

45

General — Protect transitional orfringe areas. Do not burn streambottoms.

Want to promote sprouting andkeep browse within reach. Repeatsummer fires may kill somerootstocks.

Avoid April through June nestingseason.

Avoid April through June nestingseason. Leave unburned patchesand thickets.

Leave unburned patches andthickets.

Marshland only. Do not burn inhardwood swamps.

1 MPROVEW1LDL1FEHAB1TAT

Deer Winter preferred Small or leaveunburned areas

Backing fire orpoint-source fires

2 to 4 years

Turkey

Quail

Dove

Waterfowl

Winter preferred;summer burns inJuly - August

Late winter

Winter

Small or leaveunburned areas

25+ acres

Not critical

Backing fire orpoint-source fires

Not critical. Donot ring fire

Not critical. Donot ring fire

Heading fire

2 to 4 years

1 to 2 years

Not critical

2+ yearsLate fall or winter Not critical

Coordination ofBurning These guidelines are general and will not fit all situations.

PURPOSE TIME OF BURN SIZE OF BURN TYPE OF FIRE FREQUENCY REMARKS

REDUCE FUELS Winter Large enough tobreak fuelcontinuity

Not critical. Donot ring fire.

2 to 4 years Use line-backing fire, or point-source fires under moist conditionsfor initial burn. Grid-firing techni-que excellent for maintenanceburns.

CONTROL Heavy roughs in Not critical. Not critical. Do 2 to 8 years Summer burns result in higherCOMPET1NG winter, otherwise not ring fire. rootstock kill and affect largerVEGETAT1ON not critical stems. Exclude fire from desirable

hardwoods in pine-hardwood type.

1 MPROVEFORAGE FORGRAZ1 NG

Winter throughlate spring formost situations

Not critical butwill be damagedby overuse if toosmall for herd.

Not critical. Donot ring fire.

3 years Split range and burn one-thirdeach year. Individual herbs andgrasses respond differently tofire and season of burn. Consultexpert.

1 MPROVEACCESS1B1L1TY

Will vary withunderstory anddesired use

Brownspot,winter

Varies with in-dividual situation

Depends onamount of fuelpresent

As needed Coordinate with other resource ob-jectives. They will dictate size, tim-ing and frequency of burn.

CONTROLD1SEASE

Depends on sizeof infected area.Include a bufferstrip

Strip-heading orheading fire

2 to 3 years Burn when humidity is above 500/0.Avoid leaving unburned pockets ofinfected seedlings within or adja-cent to burn.

46

PURPOSE TIME OF BURN SIZE OF BURN TYPE OF FIRE FREQUENCY REMARKS

ENHANCEAPPEARANCE

Late fall throughlate winter

Varies with eachsituation

Backing fire orpoint-source fire

1 + years Requires precise prescription toprotect vegetative type changes.Know effect of fire frequency andseason of burn on both annual andbiennial flowering plants. Providepleasing visual lines.

PERPETUATE Will vary with Will vary but Will vary with fuel Will vary with Fire intensity, timing and frequencyF1RE species usually fairly conditions and species all dictated by speciesDEPENDENT small species requirements.SPEC1ES requirements.

YOUNG P1NE Winter Varies with size Backing fire 2 to 4 years Pine diameter 3 inches or more atSTANDS of stand ground. Pine height above 10 ft.

Burn only after a strong cold frontwith rain.

D1SPOSE OFLOGG1NGDEBR1S

Not critical Small areasmean fewernighttime smokeproblems

Center firing withhelitorchpreferred

— — Smoke management is a must!Take care not to damage soil orwater resources with these hotfires. If a broadcast burn will notmeet objectives, pile - do not wind-row debris.

PREPARE S1TESFOR SEED1NG

Natural seeding,summer to earlyfall prior to seedfall.

Direct seeding,fall to late winterfor spring sowing.Previous winterfor fall sowing oflongleaf.

Large enough toprevent concen-trations of birds &rodents (usually10 acres ormore).

Large enough toprevent concen-trations of birds &rodents (usually10 acres ormore).

Not critical. Donot ring fire

Not critical.Center firing withhelitorch prefer-red if slashpresent.

— — Be careful not to kill seed trees. Iflogging debris present, manageyour smoke.

If logging debris present, smokemanagement is a must! Take carenot to damage soil or waterresources with these hot fires

PREPARE S1TESFOR PLANT1 NG

Growing seasonfor hardwoodcontrol.

Large enough toprevent concen-trations of birds &rodents (usually10 acres ormore).

Not critical.Center firing withhelitorch pre-ferred if slashpresent.

— — If logging debris present, smokemanagement is a must! Take carenot to damage soil or waterresources with these hot fires

47

Rules ofThumb1.Obtain and use latest weather and

smoke management forecasts.2. Relative humidity will roughly

halve with each 20°F rise intemperature and double with each20°F drop in temperature in agiven air mass.

3. Expect increased spotting whenrelative humidity drops below 30percent. Do not burn when therelative humidity is below 25percent.

4. Burn when mixing height isabove 1,650 feet [500 meters].

5. Do not burn under temperatureinversions.

6. Burn areas with low fuel loadingsand large-sized trees on marginaldays at the high end of theprescription window.

7. Never underburn during adrought. Soil moisture is neededto protect tree roots and lowerlitter.

8. Don't burn on organic soils unlessthe water table is very close tothe surface.

9. Heading fires produce about threetimes more particulate than back-ing fires.

10.Burn when fuels are dry, but nottoo dry. Wet fuels producesubstantially more particulatethan do dry fuels.

11.Start burning logging debris bymidmorning.

12. Site prep burning behind chop-ping or other mechanical treat-ment gives best results if done 10to 15 days after treatment.

13.Windrows are the most pollutingof all southern fuel types.

14.Broadcast burn scattered debris ifpossible.

15.Do not pile when either groundor debris is wet.

16.Dirt in piled debris will increasethe amount of smoke produced byup to four times. Shake out dirtwhile piling "bump" piles whileburning, and repile as necessary.

17.Use a smoke management plan.Consider smoke sensitive areas.Look several miles downwind anddown-drainage for potentialtargets.

18.Estimate background smoke con-centration [micrograms per cubicmeter] in the absence of highhumidities by dividing 500 by thevisibility in miles.

19. If nighttime Dispersion Indexforecast is poor or very poor[less than 13], stop burning by3 p.m. ST.

20. Doubling the Dispersion Indexi mplies a doubling of the atmos-pheric capacity to disperse smokewithin a 1,000 square mile area.

21. Assuming 1 ton of fuel per acreis being consumed by smolderingcombustion during poor nighttimedispersion conditions, expectvisibility in the smoke to be lessthan 1/2 mile within 11/2 miles ofthe fire.

48

Red FlagSituationsIf any of the followingconditions exist,analyze further beforeburning.

Underburning:■ No written plan■ No map■ No safety briefing■ Heavy fuels■ Dry duff and soil■ Extended drought■ Inadequate control lines■ No updated weather forecast

for area■ Forecast does not agree with

prescription■ Poor visibility■ Personnel or equipment

stretched thin■ Burning large area using

ground ignition■ Communications for all people

not available■ No backup plan or forces

available■ No one notified of plans to

burn

■ Behavior of test fire not asprescribed

■ A smoke-management systemhas not been used

■ Smoke-sensitive area downwindor down drainage

■ Organic soil present■ Daytime Dispersion Index

below 40■ Not enough personnel or

equipment available to controlan escaped fire

■ Personnel on fire not qualifiedto take action on escaped fire.

Debris burning - in addition to theabove:

■ Area contains windrows■ A lot of dirt in piles■ Poor nighttime smoke disper-

sion forecast■ Have not looked down drainage■ Mixing height is below 1,650

feet (500 meters)■ Debris was piled when wet■ Pile exteriors are wet

If any of the followingconditions exist,stop burning and plowout existing fire.

■ Fire behavior erratic■ Spot fire or slop-over occurs

and is difficult to control■ Wind shifting or other unfore-

seen change in weather■ Smoke not dispersing as

predicted■ Public road or other sensitive

area smoked in■ Burn does not comply with all

laws, regulations, and standards■ Large fuels igniting and burn-

ing, not enough personnel tomopup before dark and likely tosmoke in a smoke sensitive area

49

Aerial Fuels—Standing and sup-ported live and dead forest com-bustibles not in direct contact withthe ground consisting mainly offoliage, twigs, branches, cones, bark,stems, and vines (See Draped Fuels,Ladder Fuels).

Aerial Ignition—Ignition of fuels bydropping incendiary devices ormaterials from aircraft.

Age of Rough—Time in years sincethe forest floor was last reduced byfire.

Air Stagnation Advisory (ASA) —A statement issued by a NationalWeather Service office whenatmospheric conditions are stableenough that the potential exists forpollutants to accumulate in a givenarea.

Anemometer—General name forinstruments designed to measurewindspeed.

Area Ignition—Igniting, throughoutan area to be burned, a number ofindividual fires either simultaneouslyor in rapid succession and so spacedthat they soon influence and supporteach other to produce a hot, fast-spreading fire throughout the area.

Aspect—Direction toward which aslope faces.

Atmospheric Stability—A measureof the degree to which theatmosphere resists turbulence andvertical motion. In prescribed fireactivities the atmosphere is usuallydescribed as stable, neutral, orunstable.Available Fuel—That portion of thetotal fuel that would actually beconsumed under a specific set ofburning conditions.

Backing Fire—A fire spreading orset to spread into (against) the wind,or downhill. (See Flanking Fire,Heading Fire).

BEHAVE —A system of interactivecomputer programs for modeling fueland fire behavior comprised of twosubsystems: BURN and FUEL.

50

Belt Weather Kit—Belt mountedcanvas case with fitted pockets foranemometer, compass, slingpsychrometer, slide rule, water bottle,pencils, and book of weather reportforms.

Blackline—Preburning of fuels,either adjacent to a control linebefore igniting the main prescribedfire, or along a roadway as adeterrent to human-caused fires.Blackline denotes a condition inwhich there is no unburned fine fuel.

Broadcast Burn—Prescribed firethat burns over a designated area,generally in the absence of amerchantable overstory, to consumedebris that has not been piled orwindrowed.

Brown & Burn—Application ofherbicide to desiccate livingvegetation prior to burning.

Brownspot Control—A prescribedburn to control a fungal infection(brownspot disease) of longleaf pinein the "grass" (small seedling) stage.

Buildup—Cumulative effects of long-term drying on current fire danger.

Buildup Index (BUI)—A relativenumber expressing the cumulativeeffect of daily drying factors andprecipitation on fuels with a 10-daytimelag constant.

Burning Boss—Person responsiblefor managing a prescribed fire fromignition through mopup.

Burning Index (BI)—A relativenumber related to the contributionfire behavior makes to the amount ofeffort needed to contain a fire withina given fuel type. A doubling of theBI indicates twice the effort will beneeded to contain a fire in that fueltype as was previously required.

Category Day—A numerical indexrelated to the ability of the atmos-phere to disperse smoke. Forexample, in South Carolina thecurrent scale, based on VentilationFactor, ranges from 1 (poor) to 5(excellent).

Catface—Defect on the surface of atree resulting from a wound wherehealing has not re-established thenormal cross-section.

Center Firing—A method ofbroadcast burning in which fire(s) areset in the center of the area to createa convection column with strongsurface indrafts. Usually additionalfires are then set progressively nearerthe outer control lines as the indraftbuilds up, to draw the flames andsmoke toward the center of the burn.

Chain —Unit of measure in landsurvey equal to 66 feet; 80 chainsequal 1 mile.

Clearcutting—Removal of the entirestanding, merchantable timber crop.

Cold Front—The leading edge of amass of air that is colder and drierthan the air mass being replaced.

Control Line—Comprehensive termfor all constructed or natural firebarriers and treated fire edges used tocontrol a fire.

Convection Column—The risingcolumn of gases, smoke and debrisproduced by a fire. The column has astrong vertical component indicatingthat buoyant forces override theambient surface wind (See SmokePlume).

Convergence Zone—The area ofincreased flame heights and fireintensity produced when two or moreflame fronts burn together.

Crown Scorch—Browning of needlesor leaves in the crown of a tree orshrub caused by heat from a fire.

Cured—Debris or herbaceousvegetation that has dried and lost itsgreen color.

DAID (Delayed Aerial IgnitionDevice)— See Ping-pong BallSystem.

Debris Burning—In this publication,defined as any prescribed fire used todispose of scattered, piled, orwindrowed dead woody fuel in theabsence of an overstory. Such a burnoften accomplishes the objectives of aSite Prep Burn as well.

Glossary

Dew Point—Temperature to which airmust be cooled to reach saturation ata constant atmospheric pressure. Thedew point is always lower than thewet-bulb temperature, which in turnis always lower than the dry-bulbtemperature. The only exception tothis is when the air is saturated (i.e.,relative humidity is 100 percent), inwhich case all three values are equal.

Dispersion—The decrease inconcentration of airborne pollutantsas they spread throughout anincreasing volume of atmosphere.

Dispersion Index—As used in thismanual, a numerical index developedby Lee Lavdas (Southern Forest FireLaboratory). This index is anestimate of the atmosphere's capacityto disperse smoke from prescribedburns over a 1,000-square-mile area.It is related to the Ventilation Factor,but also considers the rate ofpollutant dispersion.

Draped Fuels—Needles, leaves,twigs, etc., that have fallen fromabove and have lodged on lowerbranches and brush. Part of aerialfuels.

Drift Smoke—Smoke that has beentransported from its point of originand in which convective motion nolonger dominates.

Drip Torch—Hand-held apparatusused to ignite fires by drippingflaming liquid fuel, at an adjustablerate, on the materials to be burned.The fuel is generally a mixture of 65to 80 percent diesel and 20 to 35percent gasoline.

Drought Index (Keetch-ByramDrought Index)—A numerical ratingof the net effect of evapotranspirationand precipitation in producingcumulative moisture depletion indeep duff or upper soil layers.

Dry-bulb Temperature—Thetemperature of the air.

Duff—The layer of decomposingorganic materials lying below thelitter layer and immediately above themineral soil. It is comprised of theFermentation (F) and Humus (H)layers of the forest floor.

Edge—As used in this manual, theboundary between two fairly distinctfuel types.

Emission Factor—The amount ofpollution (pounds per ton) released tothe atmosphere per unit weight of dryfuel consumed during combustion.

Emission Rate—The quantity ofpollutant released to the atmosphereper unit length of fire front per unittime.

Equilibrium Moisture Content(EMC)—The moisture content that afuel would eventually attain ifexposed for an infinite period tospecified constant values of Dry-bulbTemperature and Relative Humidity.

Fine Fuels (Flash fuels) — Fast-drying, dead fuels which have aTimelag constant of 1 hour or less.These fuels ignite readily and areconsumed rapidly when dry. Includedare grass, leaves, draped pineneedles, and small twigs.

Fire Behavior—A general term thatrefers to the combined effect of fuel,weather and topography on a fire.

Firebrand—Any flaming orsmoldering material such as leaves,pine cones, or glowing charcoal thatcould start another fire.

Firebreak—Any natural orconstructed discontinuity in a fuelbedused to segregate, stop, or control thespread of fire or to provide a controlline from which to suppress a fire.

Fire Effects—Physical, biologicaland ecological impacts of fire on theenvironment.

Fire Front—The strip within whichcontinuous flaming occurs along thefire perimeter (See Flame Depth).

Fireline Intensity (Byram'sIntensity)— The rate of heat releaseper unit time per unit length of firefront. Numerically, it is the productof the heat yield, the quantity of fuelconsumed in the Fire Front, and therate of spread.

Fire Plow—Heavy-duty share or diskplow designed to be pulled by atractor to construct Firebreaks.

Fire Rake—A long-handledcombination rake and cutting tool,the blade of which is usuallyconstructed of a single row of 4sharpened teeth.

Firing Technique—The type(s) offire resulting from one or moreignition(s), e.g., backing fire,flanking fire, heading fire, (See GridIgnition, Ignition Pattern).

Flame Depth —The depth of the FireFront at the fuel surface.

Flame Length—The distance betweenthe flame tip and the midpoint of theFlame Depth at the base of the flame(generally at the ground surface).

Flanking Fire—A Fire Frontspreading, or set to spread at roughlyright angles to the prevailing wind.

Flash Fuels—See Fine Fuels.

Flying Drip Torch—See Helitorch.

Fuel Moisture Content—Watercontent of a fuel expressed as apercentage of the ovendry weight ofthe fuel.

Fuel Moisture Indicator Sticks—Aspecially manufactured set of sticksof known dry weight continuouslyexposed to the weather andperiodically weighed to determinechanges in moisture content. Thechanges are an indication of changesin the moisture status and relativeflammability of dead fuels thatroughly correspond toTen-hourTimelag Fuels.

Grid Ignitions—Method of ignitingfires in which ignition points are setindividually at predetermined spacingwith predetermined timing throughoutthe area to be burned (see Ping-pongBall System).

51

Dew Point—Temperature to which airmust be cooled to reach saturation ata constant atmospheric pressure. Thedew point is always lower than thewet-bulb temperature, which in turnis always lower than the dry-bulbtemperature. The only exception tothis is when the air is saturated (i.e.,relative humidity is 100 percent), inwhich case all three values are equal.

Dispersion—The decrease inconcentration of airborne pollutantsas they spread throughout anincreasing volume of atmosphere.

Dispersion Index—As used in thismanual, a numerical index developedby Lee Lavdas (Southern Forest FireLaboratory). This index is anestimate of the atmosphere's capacityto disperse smoke from prescribedburns over a 1,000-square-mile area.It is related to the Ventilation Factor,but also considers the rate ofpollutant dispersion.

Draped Fuels—Needles, leaves,twigs, etc., that have fallen fromabove and have lodged on lowerbranches and brush. Part of aerialfuels.

Drift Smoke—Smoke that has beentransported from its point of originand in which convective motion nolonger dominates.

Drip Torch—Hand-held apparatusused to ignite fires by drippingflaming liquid fuel, at an adjustablerate, on the materials to be burned.The fuel is generally a mixture of 65to 80 percent diesel and 20 to 35percent gasoline.

Drought Index (Keetch-ByramDrought Index)—A numerical ratingof the net effect of evapotranspirationand precipitation in producingcumulative moisture depletion indeep duff or upper soil layers.

Dry-bulb Temperature—Thetemperature of the air.

Duff—The layer of decomposingorganic materials lying below thelitter layer and immediately above themineral soil. It is comprised of theFermentation (F) and Humus (H)layers of the forest floor.

Edge—As used in this manual, theboundary between two fairly distinctfuel types.

Emission Factor—The amount ofpollution (pounds per ton) released tothe atmosphere per unit weight of dryfuel consumed during combustion.

Emission Rate—The quantity ofpollutant released to the atmosphereper unit length of fire front per unittime.

Equilibrium Moisture Content(EMC)—The moisture content that afuel would eventually attain ifexposed for an infinite period tospecified constant values of Dry-bulbTemperature and Relative Humidity.

Fine Fuels (Flash fuels) — Fast-drying, dead fuels which have aTimelag constant of 1 hour or less.These fuels ignite readily and areconsumed rapidly when dry. Includedare grass, leaves, draped pineneedles, and small twigs.

Fire Behavior—A general term thatrefers to the combined effect of fuel,weather and topography on a tire.

Firebrand—Any flaming orsmoldering material such as leaves,pine cones, or glowing charcoal thatcould start another fire.

Firebreak—Any natural orconstructed discontinuity in a fuelbedused to segregate, stop, or control thespread of fire or to provide a controlline from which to suppress a fire.

Fire Effects—Physical, biologicaland ecological impacts of fire on theenvironment.

Fire Front—The strip within whichcontinuous flaming occurs along thefire perimeter (See Flame Depth).

Fireline Intensity (Byram'sIntensity)— The rate of heat releaseper unit time per unit length of firefront. Numerically, it is the productof the heat yield, the quantity of fuelconsumed in the Fire Front, and therate of spread.

Fire Plow—Heavy-duty share or diskplow designed to he pulled by atractor to construct Firebreaks.

Fire Rake—A long-handledcombination rake and cutting tool,the blade of which is usuallyconstructed of a single row of 4sharpened teeth.

Firing Technique—The type(s) offire resulting from one or moreignition(s), e.g., backing fire,Clanking fire, heading fire. (See GridIgnition, Ignition Pattern).

Flame Depth —The depth of the FireFront at the fuel surface.

Flame Length—The distance betweenthe flame tip and the midpoint of theFlame Depth at the base of the flame(generally at the ground surface).

Flanking Fire—A Fire Frontspreading, or set to spread at roughlyright angles to the prevailing wind.

Flash Fuels—See Fine Fuels.

Flying Drip Torch—See Helitorch.

Fuel Moisture Content—Watercontent of a fuel expressed as apercentage of the ovendry weight ofthe fuel.

Fuel Moisture Indicator Sticks—Aspecially manufactured set of sticksof known dry weight continuouslyexposed to the weather andperiodically weighed to determinechanges in moisture content. Thechanges are an indication of changesin the moisture status and relativeflammability of dead fuels thatroughly correspond toTen-hourTimelag Fuels.

Grid Ignitions—Method of ignitingtires in which ignition points are setindividually at predetermined spacingwith predetermined timing throughoutthe area to he burned (see Ping-pongBall System).

51

Hazard Reduction—Treatment ofliving and dead forest fuels to reducethe likelihood of a fire starting, andto lessen its damage potential andresistance to control.

Heading Fire—A Fire Frontspreading or set to spread with thewind or upslope.

Helitorch (Flying Drip Torch) —Aspecialized drip torch hung from, ormounted on a helicopter thatdispenses globs of ignited gelledgasoline.

Herbaceous Fuels—Grasses andother plants that contain little woodytissue.

Humus—The layer of decomposedorganic matter on the forest floorbeneath the partially decomposedlitter layer (F layer) and directlyabove the soil.

Hygrothermograph—An instrumentthat continuously records Dry-bulbTemperature and Relative Humidity.

Ignition Pattern—The manner inwhich a Prescribed Fire is ignited.The distance between ignition linesor points and the sequence of ignitingthem, as determined by fuel, topo-graphy, weather, ignition system,firing technique, and other factorsinfluencing fire behavior and theobjectives of the burn (See FiringTechnique).

In-stand Wind (Midflame Wind)—Windspeed within a stand at abouteye level.

Inversion—In this publication,defined as a layer of the atmospherethrough which the temperatureincreases with increasing height.

Keetch-Byram Drought Index—SeeDrought Index.

Ladder Fuels—Fuels that providevertical continuity between the groundand tree crowns, thus creating apathway for a surface fire to move intothe overstory tree crowns.

Line Ignition—Setting a line of fireas opposed to individual spots.

Litter—The top layer (L layer) of theforest floor directly above thefermentation layer (F layer),composed mainly of recently fallenleaves and pine needles, but alsoincludes dead twigs, bark fragments,etc. (See Duff).

Logging Debris—Unwanted treeparts remaining after harvest,including tree crowns, unutilizedlogs, and uprooted stumps.

Low-Level Jet—See Wind Profile.

Midflame Wind—See In-stand wind.

Mineral Soil—Soil layers below thepredominantly organic horizons.

Mixing Height —The height to whichrelatively vigorous mixing of theatmosphere occurs.

Mopup—Extinguishing or removingburning material, especially nearcontrol lines after an area has burnedto make it safe, or to reduce residualsmoke.

Muck—See Organic Soil.

National Fire Danger RatingSystem ( NFDRS)—The methodcurrently used by the USDA ForestService, and many otherorganizations to integrate the effectsof topography, fuels, and weather intonumerical indices of fire danger on aday-to-day basis.

One-Hour Timelag Fuels—Finefuels consisting mainly of deadherbaceous plants, roundwood lessthan about 1/4-inch in diameter, andthe uppermost Litter Layer.

Organic Soil—Any soil or soilhorizon containing at least 30 percentorganic matter; examples are peatand muck.

Particulate (Total SuspendedParticulate (TSP))—Any liquid orsolid particles temporarily suspendedin the atmosphere. See PM-10.

Peat—See Organic Soil.

Ping-pong Ball System—A methodof igniting fires with the use of aDelayed Aerial Ignition Device(DAID). The device is a polystyreneball, 1.25 inches in diameter thatcontains a combustible chemical. Theballs are fed into a dispenser,generally mounted in a helicopter,where they are injected with anotherchemical and drop through a chuteleading out of the helicopter. Thechemicals react thermally and ignitein about 30 seconds. The spacebetween ignition points on the groundis primarily a function of helicopterspeed, gear ratio of the dispenser,and the number of chutes used (up to4) (See Grid Ignition).

PM-10—Particulate with an aero-dynamic diameter smaller than orequal to 10 micrometers.

Prescribed Burning—The controlledapplication of fire to wildland fuelsin either a natural or modified state,under specified environmentalconditions which allow the fire to beconfined to a predetermined area andat the same time produce theintensity required to attain plannedresource management objectives.

Psychrometer—The general name forinstruments designed to determine themoisture content of air. A psychro-meter consists of dry-and wet-bulbthermometers that give the Dry-andWet-bulb Temperatures, which in turnare used to determine RelativeHumidity and Dew Point.

Relative Humidity—The ratio,expressed as a percentage of theamount of moisture in the air, to themaximum amount of moisture the airis capable of holding under the sameconditions.

Residence Time —The time (seconds)required for the Fire Front to pass astationary point at the surface of thefuel. Numerically, it is the FlameDepth divided by the rate of spread.

Residual Smoke — Smoke producedby smoldering material behind theactively burning Fire Front.

52

Ring Fire—A tire started by ignitingthe perimeter of the intended burnarea so that the ensuing Fire Frontsconverge toward the center of theblock.

Rough—The live understory and deadfuels that build up on the forest floorover time.

Scorch Height (Scorch Line)—Theaverage height to which foliage hasbeen browned by fire.

Site Prep Burn —A fire set to exposeadequate mineral soil and controlcompeting vegetation until seedingsof the desired species becomeestablished (See Debris Burning).Slash—Debris resulting from suchnatural events as wind, tire, or snowbreakage, or such human activities aslogging or road construction .

Smoke Concentration—The weightof combustion products (microgramsper cubic meter) found in a givenvolume of air.

Smoke Management—Application ofknowledge of fire behavior andmeteorological processes to minimizeair quality degradation duringPrescribed Burning.Smoke Plume—The gases, smoke,and debris that rise slowly from afire while being carried along theground because the buoyant forcesare exceeded by those of the ambientsurface wind (See ConvectionColumn).

Smoke-sensitive Area (SSA)—Anarea in which smoke from outsidesources is intolerable.

Smoldering Combustion Phase—Combustion associated with residualburning of forest fuels behind theFire Front. Emissions are at leasttwice that of the Fire Front, andconsist mainly of tars.Spot Fire—Fire ignited outside theperimeter of the main fire by a FireBrand.

Spot Weather Forecast—Specialprediction of atmospheric conditionsat a specific site, sometimes requestedby the Burning Boss before igniting aprescribed fire.

Stagnant Conditions—Conditionsunder which pollutants build up fasterthan the atmosphere can dispersethem.Strip-Heading Fire—A series oflines of fire upwind (or downslope)of a firebreak or backing fire thatwill burn with the wind toward thefirebreak or backing fire.Ten-Hour Time lag Fuels—Deadroundwood 1/4 to 1 inch in diameterand, to a rough approximation, thetop 3/4 inch of the litter layer.

Timelag—The drying time, underspecified conditions, required for adead fuel to loose about 63 percentof the difference between its initialmoisture content and its EquilibrumMoisture Content. Providingconditions remain unchanged, a fuelwill reach 95 percent of its EMCafter four timelag periods.Tractor-Plow—Any tracked vehicle,with a plow for exposing mineralsoil, with transportation andpersonnel for its operation.

Transport Windspeed—A measureof the average rate of the horizontalmovement of air throughout themixing layer.

Underburning— Prescribed burningunder a timber canopy.Ventilation Factor—An indicator ofthe lower atmosphere's potential todiffuse and disperse smoke.Numerically, it is the product of theMixing Height and the TransportWindspeed (See Dispersion Index).Wet-bulb Temperature—Technically,the temperature registered by the wet-bulb thermometer of a Psychrometer.It is the lowest temperature to whichair can be cooled by evaporatingwater into it at a constant atmos-pheric pressure.

Wet li ne —A line of water, or waterand chemical retardant, sprayed alongthe ground and which serves as atemporary control line from which toignite or stop a low-intensity fire.

Wind Direction—Compass directionfrom which the wind is blowing.Wind Profile—A plot of windspeedover height above the earth's surface.A rapid increase with height to amaximum windspeed within 1,000feet above ground and then a slowdecrease above that peak is commonlycalled a low-level jet and is one ofseveral adverse wind profiles.Windrow—Woody debris that hasbeen piled into a long continuousrow.

53

SuggestedReadingAbercrombie, James A.,Jr; Sims,Daniel H. 1986. Fell and burn forlow-cost site preparation. ForestFarmer. 46(1): 14-17.

Andrews, Patricia L. 1986.BEHAVE: Fire behavior predictionand fuel modeling system-burnsubsystem, part 1. Gen Tech. Rep.INT-194. Ogden, UT: U.S.Department of Agriculture, ForestService, Intermountain Forest andRange Experiment Station. 130 p.

Boyer, William D. 1987. Volumegrowth loss: a hidden cost of periodicprescribed burning in longleaf pine.Southern Journal of Applied Forestry.11(3): 154-157.

Brown, A.A.; Davis, K.P. 1973.Forest fire: control and use. 2d ed.New York: McGraw-Hill. 584 p.

Burgan, Robert E.; Rothermel,Richard C. 1984. BEHAVE : Firebehavior prediction and fuel modelingsystem - fuel subsystem. Gen. Tech.Rep. INT-167. Ogden, UT: U.S.Department of Agriculture, ForestService, Intermountain Forest andRange Experiment Station. 126 p.

Byram, George M. 1954.Atmospheric conditions related toblowup fires. Station Pap. 35.Asheville, NC: U.S. Department ofAgriculture, Forest Service,Southeastern Forest ExperimentStation. 34 p.

Countryman, Clive M. 1971. Thishumidity business: whats its all aboutand its use in fire control? Berkeley,CA: U.S. Department of Agriculture,Forest Service, Pacific SouthwestForest and Range Experiment Station.15 p.

Croker, Thomas C., Jr. 1967. Crop-seedling method for planning brown-spot burns in longleaf pine. Journal ofForestry. 65(7): 488.

Golden, Michael S. 1987.Development and evaluation of low-cost systems for artificial regenerationof pine. Ga. For. Res. Pap. 71.Macon, GA: Georgia ForestryCommission. 12 p.

Grano, Charles X. 1970. Eradicatingunderstory hardwoods by repeatedprescribed burning. Res. Pap. SO-56.New Orleans, LA: U.S. Departmentof Agriculture, Forest Service,Southern Forest Experiment Station.11 p.

Greene, Thomas A.; Shilling,Charles L. 1987. Predicting girdlingprobability for pine and hardwoodsaplings in low-intensity backfires.Forest Science. 33(4): 1010-1021.

Hough, W.A. 1968. Fuelconsumption and fire behavior ofhazard reduction burns. Res. Pap.SE-36. Asheville, NC: U.S.Department of Agriculture, ForestService, Southeastern ForestExperiment Station. 7 p.

Hough, W.A.; Albini, F.A. 1978.Predicting fire behavior in palmetto-gallberry fuel complexes. Res. Pap.SE-174. Asheville, NC: U.S.Department of Agriculture, ForestService, Southeastern ForestExperiment Station. 44 p.

Hughes, Ralph. 1975. The nativevegetation in south Florida related tomonth of burning. Res. Note. SE-222.Asheville, NC: U.S. Department ofAgriculture, Forest Service, South-eastern Forest Experiment Station.8 p.

Johansen, R.W. 1968. Fire controlconsiderations in pine plantations. In:Proceedings seventh forestry forum;1968 June 12-13; Auburn, AuburnUniversity, AL: 14-19.

Johansen, Ragnar W. 1981.Windrows vs. small piles for forestdebris disposal. Fire ManagementNotes. 42(2): 7-9.

Johansen, R.W. 1984. Prescribedburning with spot fires in the GeorgiaCoastal Plain. Ga. For. Res. Pap. 49.Macon, GA: Georgia ForestryCommission. 7 p.

Johansen, R.W. 1985. Is aerialignition a panacea to the southernprescribed burner? In: Shoulders,Eugene, ed. Proc. 3rd biennialsouthern silvicultural researchconference; 1984 November 7-8;Atlanta, GA. Gen. Tech. Rep. SO-54.New Orleans: U.S. Department ofAgriculture, Forest Service, SouthernForest Experiment Station: 514-518.

Johansen, Ragnar W. 1987. Ignitionpatterns & prescribed fire behavior insouthern pine stands. Ga. For. Res.Pap. 72. Macon, GA: GeorgiaForestry Commission. 6 p.

Johansen, Ragnar W.; McNab, W.Henry 1977. Estimating loggingresidue weights from standing slashpine for prescribed burns. SouthernJournal of Applied Forestry. 1(2): 2-6.

Johansen, R.W.; Wade, D.D. 1987.An insight into thinning young slashpine stands with tire. In: Proceedingsof the fourth biennial southernsilvicultural research conference; 1986November 4-6; Atlanta, GA. Gen.Tech. Rep. SE-42. Asheville, NC:U.S. Department of Agriculture,Forest Service, Southeastern ForestExperiment Station. 103-106.

Johansen, Ragnar W.; Wade, DaleD. 1987. Effects of crown scorch onsurvival and diameter growth of slashpines. Southern Journal of AppliedForestry. 11(4): 180-184.

Johnson, Von J. 1984. Estimatingmoisture content in litter. SouthernJournal of Applied Forestry. 8(4):197-201.

54

Lavdas, Leonidas G. 1986. Anatmospheric dispersion index forprescribed burning. Res. Pap. SE-256.Asheville, NC: U.S. Department ofAgriculture, Forest Service, South-eastern Forest Experiment Station.33 p.

Lewis, Clifford E.; Harshbarger,Thomas J. 1986. Burning and grazingeffects on bobwhite foods in thesoutheastern Coastal Plain. WildlifeSociety Bulletin. 14(4): 455-459.

Lilieholm, Robert J.; Hu, Shih-Chang. 1987. Effect of crown scorchon mortality and diameter growth of19-year-old-loblolly pine. Southern

Journal of Applied Forestry. 11(4):209-211.

Lotan, James E. (and others). 1981.Effects of fire on flora: a state ofknowledge review. Gen. Tech. Rep.WO-16. Washington: U.S. Departmentof Agriculture, Forest Service. 71 p.

Lansford, James. 1987. Prescribedfire in the Southeast-five steps to asuccessful burn. Fire ManagementNotes. 48(3): 30-35.

Lyon, L. Jack (and others). 1978.Effects of fire on fauna: a state ofknowledge review. Gen. Tech. Rep.WO-6. Washington: U.S. Departmentof Agriculture, Forest Service, 22 p.

Martin, Robert E. (and others).1979. Effects of fire on fuels; a stateof knowledge review. Gen. Tech. Pap.WO-13. Washington: U.S. Departmentof Agriculture, Forest Service, 64 p.

McKevin, Martha R.; McKee,William H., Jr. 1986. Long-termprescribed burning increases nutrientuptake and growth of loblolly pineseedlings. Forest Ecology andManagment. 17(4): 245-252.

McMinn, James W. (and others).1987. Pre-harvest estimation of loggingresidues in middle Georgia. Ga. For.Res. Pap. 73. Macon, GA: GeorgiaForestry Commission. 6 p.

McNab, W. Henry. 1976. Prescribedburning and direct-seeding oldclearcuts in the Piedmont. Res. NoteSE-229. Asheville, NC: U.S.Department of Agriculture, ForestService, Southeastern ForestExperiment Station. 4 p.

McPherson, Guy R.; Rasmussen,G. Allen; Wright, Henry A.;Britton, Carlton M. 1986. Gettingstarted in prescribed burning.Management Note 9. Lubbock: TexasTech University, Texas Tech Rangeand Wildlife Manage. Dept. 5 p.

Mobley, Hugh E.; Kerr, Ed. 1973.Wildfire versus prescribed fire in thesouthern environment. Atlanta: U.S.Department of Agriculture, South-eastern Area, State and PrivateForestry. 6 p.

Paul, James T.; Lavdas, LeonidasG.; Wells, Wesley. 1987. Use ofgeneral weather and Dispersion Indexto minimize the impact of smoke onhighway visibility. Ga. Forest Res.Pap. 69. Macon, GA: GeorgiaForestry Commission. 10 p.

Prescribed Fire and Fire EffectsWorking Team, National WildfireCoordinating Group. 1985.Prescribed fire smoke managementguide. Publication 420-1. NFES No.1279. Boise, ID: Boise InteragencyFire Center. 28 p.

Rothermel, Richard. 1983. How topredict the spread and intensity offorest and range fires. Gen Tech. Rep.INT-143. Ogden, UT: U.S.Department of Agriculture, ForestService, Intermountain Forest andRange Experiment Station. 161 p.

Sackett, Steven S. 1975. Schedulingprescribed burns for hazard reductionin the Southeast. Journal of Forestry.73(3): 143-147.

Sandberg, D.V. (and others). 1979.Effects of fire on air: a state ofknowledge review. Gen. Tech. Rep.WO-9. Washington: U.S. Departmentof Agriculture, Forest Service, 40 p.

Schroeder, Mark J.; Buck, CharlesC. 1970. Fire weather. Agric. Handb.360. Washington: U.S. Department ofAgriculture, Forest Service. 229 p.

Seigel, William C. 1985. Legali mplications of prescribed burning inthe South. In: Proceedings onPrescribed Fire and SmokeManagement in the South Conference;1984 September 12-14; Atlanta, GA.Asheville, NC: U.S. Department ofAgriculture, Forest Service,Southeastern Forest ExperimentStation: 77- 85.

Tiedemann, Arthur R. (and others).1979. Effects of fire on water: a stateof knowledge review. Gen. Tech. Rep.WO-10.Washington: U.S. Departmentof Agriculture, Forest Service. 28 p.

U.S. Department of Agriculture,Forest Service, Southeastern ForestExperiment Station. Prescribedburning symposium. 1971 April 14-16.Charleston SC. Asheville, NC. 160 p.

U.S. Department of Agriculture,Forest Service, Southeastern ForestExperiment Station. 1976. Southernforestry smoke managementguidebook. Gen. Tech. Rep. SE-l0Asheville, NC. 140 p.

U.S. Department of Agriculture,Forest Service. 1977. Fire byprescription symposium; 1976 October13-15; Atlanta. Washington. 127 p.

U.S. Department of Agriculture,Forest Service, Southeastern ForestExperiment Station. 1985. Prescribedfire and smoke management in theSouth: Proceedings of a symposium;1984 September 12-14; Atlanta, GA.Asheville, NC. 194 p.

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U.S. Department of Agriculture,Forest Service, Southern Region.1988. Draft environmental impactstatement: vegetation management inthe Costal Plain/Piedmont. Vol. I andII. Mange. Bull. R8-MB 15. Atlanta.

Van Lear, D.H; Danielovich, S.J.1988. Soil movement after broadcastburning in the southern Appalachians.Southern Journal of Applied Science.12(1): 49-53.

Villarrubia, CR.; Chambers J.L.1978. Fire, its effect on growth andsurvival of loblolly pine, Pinus taedaL. Louisiana Academy of Science. 41:85-93.

Wade, Dale D. 1983. Firemanagement in the slash pineecosystem. In: Proceedings, themanaged slash pine ecosystem. 1981June 9-11; Gainesville, FL.Gainesville, FL: University ofFlorida, School of Forest Resourcesand Conservation, 203-227, 290-294,301.

Wade Dale D. 1986. Linking firebehavior to its effects on living planttissue. In: Proceedings of the 1986Society of American ForestersNational Convention; 1986 October5-8; Birmingham, AL. Bethesda,MD: Society of American Foresters.112-116.

Wade, Dale D.; Wilhite, Lawrence P.1981. Low intensity burn prior tobedding and planting slash pine is oflittle value. In: Proceedings, 1stsouthern silvicultural researchconference; 1980 November 6-7;Atlanta, GA. Gen. Tech. Rep. SO-34.New Orleans: U.S. Department ofAgriculture, Southern ForestExperiment Station: 70-74.

Waldrop, Thomas A. (and others).1987. Long term studies of prescribedburning in loblolly pine forests of theSoutheastern Coastal Plain. Gen.Tech. Rep. SE-45. Asheville, NC:U.S. Department of Agriculture,Forest Service, Southeastern ForestExperiment Station. 23 p.

Weise, David R.; Johansen, R.W.;Wade, Dale D. 1987. Effects of springdefoliation on first-year growth ofyoung loblolly and slash pines. Res.Note SE-347. Asheville, NC: U.S.Department of Agriculture, ForestService, Southeastern ForestExperiment Station. 4 p.

Wells, Carol G. (and others). 1979.Effects of fire on soil: a state ofknowledge review. Gen. Tech. Rep.WO-7. Washington: U.S. Departmentof Agriculture, Forest Service. 34 p.

For information about articles,contact: USDA Forest Service,Southern Region, Fire and AviationStaff Unit, 1720 Peachtree Road NW,Atlanta, GA 30367 or USDA ForestService, Southeastern ForestExperiment Station, P.O. Box 2680,Asheville, NC 28802

Wade, Dale D.; Johansen, R.W.l986.Effects of fire on southern pine:observations and recommendations.Gen. Tech. Rep. SE-41. Asheville,NC: U.S. Department of Agriculture,Forest Service, Southeastern ForestExperiment Station. 14 p.

Wade, Dale D.; Lewis, Clifford E.1987. Managing southern grazingecosystems with fire. Rangelands.9(3): 115-119.

56

Five Steps to a SuccessfulPrescribed Burn

ANALYSIS

PRESCRIPTION

PREPARATION

EXECUTION

EVALUATION