GETTING STARTED IN PRESCRIBED BURNING1

by GUY R. McPHERSON, G. ALLEN RASMUSSEN, HENRY A. WRIGHTand CARLTON M. BRITTON

Department of Range and Wildlife Management Texas Tech University

Lubbock, TX 79409

Prescribed burning for range improvement hasincreased dramatically during the past few years. This has been especially evident in Texas. Prescribed fire can accomplish many rangeimprovement objectives with a single treatment.For example, one burn can control noxious brush,increase herbage yield, increase utilization, increase forage availability, improve wildlife habitat, andcontrol various diseases.

Management after the burn is essential if desiredresults are to be obtained. Grazing animalsfrequently concentrate on a burn because forage ismore palatable, nutritious, and available. There-fore, alternate forage will have to be available untilthe pasture is ready for grazing.

EquipmentEquipment required before beginning a pres-

cribed burning program includes:

pumperbelt weather kitdrip torches hand tools (shovels, swatters, backpack

radio communication (depending on size ofunit)heavy equipment (for line preparation andsuppression activities).

pumps)

These items need to be gathered in advance toensure they are operative and available for use.

A pumper is essential because water is thequickest method to cool an escaped fire, allowing itto be put out. The type of pumper may vary froma cattle sprayer to a fire truck, but it should meetthe following specifications:

1) minimum capacity of 100 gallons2 )minimum of 50 feet of hose3 )hand held nozzle with adjustable spray.

In addition, the terrain and vegetation ofrangelands require the pumper to be maneuvera-ble. Texas Tech University has used a 100 gallonslip-on pumper for the past 19 years with noproblems. This pumper is placed in the bed of a 3/4ton 4 x 4 pickup to gain maneuverability.

Weather forecasts cannot accurately predictchanges in temperature, relative humidity, and

1Contribution No. T-9-455, College of Agricultural Sciences,Texas Tech University.

wind speed through the course of a day, so thesevariables must be measured on site. A belt weatherkit needs to contain the following:

1) psychrometer (temperature and relative

2) bottle of water3) anemometer (wind speed)4)note pad and pencil5)compass.

Grassland fire behavior is closely related to localweather variables. Air temperature, relativehumidity, and wind have the greatest impact onfire behavior. Prescriptions developed to meetspecific objectives for different fuel types dependon these weather variables. Weather changes throughout the day, causing changes in firebehavior. Wind speed affects fire behavior immediately, whereas changes in relative humiditydo not affect fine fuel moisture content for approximately 1/2 hour. Because of this time lag,weather variables are measured every 1/2 hr and recorded for reference throughout the burn. If theperson responsible for taking the weather is not

humidity)

Suppression can be facilitated w i t h proper equipment. A slip-on pumper unit is desirable. Appropriate hand tools include(from left to right) backpack pumps, axes, fires swatters, andshovels.

familiar with the area, a compass is recommendedfor wind direction.

Ignition sources used in prescribed burning aredivided into two categories, ground and aerialtechniques. The most common ground techniqueutilizes drip torches. The drip torch consists of areservoir tank, spout, and wick. There are severaltypes available commercially. The mixture of fuelused in rangeland prescribed fires is 70% diesel and30% gasoline.

Aerial ignition techniques include the helitorchand aerial ignition device system. These techniquesrequire specialized training and will not bediscussed here. However, burns larger than 3,000acres with rough topography are candidates foraerial ignition.

Hand tools are needed to remove any fuelbridges (areas where fine fuel extends across thefire break) and suppress spot fires. The mostcommon tools are shovels, rakes, and axes. Use ofspecialized tools such as the fire swatter andbackpack water pumps for suppression are veryeffective. Fence cutters are also recommended toallow quick access, with limited damage, to anadjacent pasture if a spot fire is beyond reach ofthe pumper.

Communication is essential during a prescribedfire. When the unit is too large for effective voicecommunication, radios are recommended. Two-wayradios are especially useful because of their greaterrange and the advantage of assigned channels.Citizen band radios will work, but the fire bossmust be aware of their limitations.

Establishment of mineral soil, dozed lines is thesafest practice for securing the perimeter of a unitto be burned. Equipment needed to make mineralsoil lines will vary with topography and vegetation. A farm tractor with a blade or disk will suffice onlevel areas with few rocks and small brush, but heavy equipment (bulldozer or maintainer) may berequired on rough, rocky terrain or areas with large brush. Regardless of the equipment used, thebreak must be clear of fuel bridges. Heavyequipment may also be used for suppressionactivities when the unit is being burned.

OrganizationThe success of a prescribed fire is largely

dependent upon the level of planning. Dozed lines should be constructed and arrangements made forequipment several weeks in advance. Finally,everyone should know their task on the day of theburn. Teamwork and communication are essentialfor conducting a safe, efficient prescribed fire.

Several aspects of prescribed burning should beaddressed early in the planning process. Specificobjectives for burning individual pastures should

be identified. Preburn treatments, includingmechanical and herbicidal treatments, should beconsidered. The pasture to be burned must bedeferred from grazing for one growing seasonbefore burning to ensure adequate fine fuel. General insurance for the ranch should provideliability protection.

Final preparations for burning can be made afterequipment is secured and dozed lines areconstructed. Several days before burning, facilities(feeders, pens, fences, electric transmission poles,oil and gas structures, buildings) and dozed lines should be inspected. Dozed lines should expose mineral soil, and be 6 to 8 feet wide. Finally, anextended weather forecast is necessary todetermine the feasibility of burning within thenext several days.

Number of people required on a particularprescribed burn will depend on fuel characteristics, size of the unit, and personnel experience.Pesonnel should be divided into the fire boss,pumper crew, and ignition crew.

The fire boss serves several functions infacilitating a smooth burn. This person isresponsible for determining the type of ignitionpattern needed to accomplish the objectives, whenignition should occur, and where suppressioncrews should be placed. Knowledge of prescribedfire behavior and its interactions with fuel and weather variables allow the fire boss to determineif desired objectives can be met. If objectives

A belt weather kit is used to monitor temperature, relativehumididty, and wind speed. A sling psychrometer isdemonstrated in the foreground and a windspeed indicator inthe background.

The fire boss should give a pre-burn briefing to explainignition sequence and crew assignments.

cannot be met or conditions create a safety risk,the fire is not ignited, or put out if already in progress.

An objective view of the fire allows the fire bossto alter ignition pattern to account for changingfuel and weather conditions. For example, slight changes in wind direction may dictate a change inignition pattern. The fire boss is also the keycommunication link between the entire burningcrew.

The fire boss places the pumper crew in the areawhich has the greatest danger of fire escape.

Examples of this would be when a bluff, ridge, orareas with heavy or volatile fuels are next to thedozed line. These conditions alter wind patternsand fire behavior creating increased risks of spotfires.

Suppression crew (pumper crew) of 1 to 4 peopleis normally sufficient on burns of 1000 acres orless. This crew is responsible for patrolling downwind of the fire to check for spot fires and putthem out. The fire boss should tell them where the greatest danger may be, but they must be awarethat spot fires can occur anywhere. If the pumpercrew finds a spot fire outside the unit, all ignitionis stopped until the spot fire is controlled. Ignitioncrew should help the suppression crew contain thespot fire if required. Further ignition does not takeplace until the fire boss determines it is safe.

The primary responsibility of the ignition crew isto ignite the unit under the fire boss’s direction.They also serve as a second suppression crew. Many techniques have been developed to igniteprescribed fires. The safest, under most conditions,is to divide the unit into two parts, firelines andheadfires. Firelines are burned under cool, moistconditions, while the headfire is burned underhotter, dryer conditions needed to achieve thedesired objectives.

RulesPrescribed fires can be safe and efficient if a few

1) Check the unit several days beforehand. Alldozed lines and structures within the unit(power lines, oil tanks, hunting stands, etc.) must be checked.

rules are followed.

FIRELINE

(100

RH

TEMP 7

WIND 8-

-500ft

25-40%

0-80 O F

15 mph

)

NDOZED LINES

RH 40- 60%TEMP 40- 60 OF

WIND 0-10 mph

Generalized fire plan for conducting prescribed burns. Fireline width depends on fuel type and amount.

T h e strip headfire ignition pattern is commonly used to burnfirelines. Personnel wi th torches proceed in a staggeredpattern.

2) Obtain a weather forecast. Informationneeded is:

a) predicted wind speed and direction b) temperaturec) relative humidityd) time of next major wind shifte) stability of atmosphere.

A spot fire weather forecast from theNational Weather Service can be obtained forspecific areas.

3) Call all neighboring land owners, fire andsheriff departments before igniting a fire.

4) Equipment must be available and operational.It is recommended that a check list bedeveloped and used.

5) Make sure all personnel know their dutiesand how the burn will be conducted.

6) Stay within fire prescriptions that aredeveloped to meet objectives.

7) Never burn when there are one or more ofthe following "RED FLAG CONDITIONS":

FirelinesFirelines (areas between dozed lines) are

generally burned on the north and east sides of thepasture. This assumes that the head fire will beburned with a southwest wind. Fireline widthvaries from 100 feet for low volatile fuels (such as

mesquite-tobosagrass) to 500 feet for high volatilefuels (such as juniper-mixed grass). The prescrip-tion for burning firelines is:

1) temperature 40-60°F2) relative humidity 40-60%3) wind speed 0-10 mph.

This prescription minimizes the chance of spotfires.

The most common ignition pattern for burningfirelines is the strip headfire technique. This technique involves igniting a series of lines of fireupwind of a dozed line in such a way that noindividual line of fire will develop to a high level ofintensity before it reaches the dozed line oranother line of fire. The first strip is ignited withina few feet of the dozed line. The second strip isignited 5 to 20 feet upwind of the first. Strip widths should be narrow in heavy fine fuel andwider in light fuel. The third and subsequent stripsshould be wider, since there is a decreasing chance of spot fires as the width of the burned out areaincreases. Personnel with torches should be in astaggered pattern. It is important for torch carriersto maintain visual or verbal contact with thepeople on both sides to prevent overrunning aslow-moving torch carrier with fire.

The number of personnel required will dependon fuel type and width of firelines. Firelines inlow-volatile fuel types can be burned safely with asfew as 5 people. A fire boss, a 2-man pumper crew,and a 5-man ignition crew can burn 3 miles of 100-foot wide fireline in 4 hours. More people and timeare required for firelines wider than 100 feet.

For the headfire, f ine fuel should be ignited downwind fromthe dozed lines and f rom major fuel breaks in large pastures.

Good communication is imperative for safe,effective fireline burning. This is especially true inthe evening, when prescription conditions areoften present. Radios for the fire boss, the pumpercrew, and every second torch carrier are desirable.Radios can be used to: 1) inform the pumper crewthat a torchman needs fuel; 2) announce a spotfire; 3) tell torchmen about approaching topogra-phic features or turns in the fireline; 4) control thepace of ignition; and 5) improve efficiency of allphases of the operation.

HeadfiresThe pasture can be burned with a headfire after

fireline burning is completed. The prescription forburning headfires in west Texas is:

1) temperature 70-80oF2) relative humidity 25-40%3) wind speed 8-15 mph.

Since firelines are usually established on the north and east sides of the pasture, wind direction shouldbe west, southwest, or south for the headfire.

Pasture size, shape, and topography influencethe number of people required for headfireignition. Fine fuel should be ignited on the north and east side of each fuel break (roads, drainages, rocky ridges). The number of fuel breaks willdetermine time and manpower requirements forignition. A flat 200 acre pasture with continuousfine fuel may require ignition only on the southand west dozed lines. O n the other hand, a 3,000-acre pasture dissected by several roads, rivers, andsteep ridges will require several miles of ignition.

A fire boss should be designated on headfires.This is especially important on large fires, wherepeople and equipment can become spread over a large area. The fire boss coordinates the ignitionsequence, monitors weather conditions, and makesdecisions regarding conduct of the burn.

Equipment requirements on headfires include apumper truck, a belt weather kit, several drip torches, and radios. The pumper truck can be used to patrol the downwind fireline. A post-burn patrolshould be made around the entire pasture to checkfor any burning material near the firelines.Burning material should be moved 50 feet insidethe fireline.

Getting ExperienceExperience is the best teacher of fire behavior.

Before burning a large pasture, the inexperiencedprescribed burner can learn quickly by observingprescribed fires lit by other people. Importantpoints to observe are:

1) organization and efficiency2) communication between torchmen

Junipers are high-volatile fuels capable of lofting firebrandsseveral hundred feet. Caution should be exercised with usingfire in juniper habitats.

3) ignition pattern4) number of people and their assignments5) placement of pumper.

After watching a few burns, the next step isignition, of several small fires. Considerable knowledge can be learned about fire behavior byburning small (less than 1 acre) units under a widerange of weather condition. Lighting several fires is the only way to learn what environmental andfuel conditons are required to produce desired firebehavior. Be sure to start gaining experience inlow-volatile fuels first. After several years ofexperience, high-volatile fuels can be attempted.

AcknowledgementsThe authors wish to thank the following

individuals for their contribution to the Texas TechFire Program: Stephen C. Bunting, Frank (Fee) E.Busby, Robert G. Clark, Ricardo DeLeon, RobertA. Gordon, Alan L. Heirman, Bob L. Karr, DonKlebenow, Robert A. Masters, Lee F. Neuensch-wander, Frederick H. Roberts, Steve H. Sharrow, Michael A. Smith, Allen A. Steuter, Kenneth J. Stinson, Jon P. Weddle, Jeffrey R. Weigel, andRobert L. Wink.

C O V E R PHOTO: Prescribed burning of mesquitetobosagrass range in west Texas.