for 406

FOR 406

Tend

Regenerate

Harvest

Prescribed burning is...

• Applied in a skillful manner• At a definite location & time• Under pre-defined weather conditions• To achieve specific management objectives

Anything else is a

PinesWestern larchDouglas-firGiant sequoia

PinesWestern larchDouglas-firGiant sequoia

OaksEucalyptusOaksEucalyptus

“Fire and life, in brief, form anecessary kind of symbiosis.”

Stephen Pyne

WILDWILD

Healthy Forests Restoration Act 2003

A fire is not a fire…

Surface Fire

Ground Fire

Crown Fire

I (kW m-1) = 2.598 L2.174I (kW m-1) = 2.598 L2.174

Frontal Fire IntensityFrontal Fire Intensity

I (kW m-1) = 300 L2I (kW m-1) = 300 L2

Average flame le

ngthWIND

~0.5 mI = 58 kW m-1

~1.0 m~1.0 m

Low IntensityLow Intensity

I = 300 kW m-1I = 300 kW m-1

~0.5 mI = 75 kW m-1

~0.5 mI = 75 kW m-1

Low IntensityLow Intensity

~91 mI = 2,484,300 kW m-1

~91 mI = 2,484,300 kW m-1

High IntensityHigh Intensity

<1.0 m (3 feet)<1.0 m (3 feet)

Why use prescribed fire?

• Reduces hazardous fuels


• Controls woody understory

Why use prescribed fire?• Stimulates natural regeneration & increases

diversity of ground flora

Why use prescribed fire?• Improves wildlife habitat & livestock forage


• Controls certain insects & diseases

Why use prescribed fire?• Recycles nutrient cations (Ca, Mg, P, K) &

stimulates N fixation

Why use prescribed fire?• Restores a natural (pre-European settle-

ment) ecological process

Why use prescribed fire?• Enhances aesthetics & improves access


• Watch it burn!

WeatherWeather

• Fuel moisture

• Fire behavior

• Fuel moisture

• Fire behavior

WeatherWeather

Good forecastsare essential!

Good forecastsare essential!

• Wind– Speed & direction steady

– 5 mph or less in the stand

– Direction more important than speed

– Interacts with topography

Weather for prescribed fire

• Relative humidity– 25 to 40%

M N M

RH


• Temperature– <90o F (35o C)

– Lethal temperature for plant tissue ~145o F

– High temperature dry fuels quickly


• RainfallWeather for prescribed fire

• Airmass stability– Resistance of atmosphere to vertical

movement


• Airmass stability—unstable – low resistance to vertical movement (large

decrease in temperature with altitude)


• Airmass stability—stable – high resistance of to vertical movement

(small decrease in temperature with altitude)


Mixing height2000-6500 ft agl

Transport windspeed10-20 mph

• Frontal activity

- No approaching fronts, esp. cold fronts


LL

ColdCold

Stationary

Stationary

WarmWarm

WIND

WIND

Goal: accurately predict fire intensity & behavior

Fine-fuel moisture & loading

• Influenced by all the elements of weather

• Fuel time lags

Fuel moisture lags(Time it takes for a fuel to lose 63% of its moisture)

Time lag Fuel diameter

1-hour (fine fuels) <¼ inch (twigs, dead grass, leaves, needles)

10-hour ¼-1 inch (twigs, small branches, cones)

100-hour 1-3 inch (branches, tops)

1000-hour >3 inch (large branches, tops, logs)



• Fuel time lags

• 8-10% low risk conditions

• 10-15% high risk conditions



• Fuel time lags

• 8-10% low risk conditions

• 10-15% high risk conditions

• Measurement– Oven drying– Fuel sticks– Bending needles

Fire Danger Rating Systems

• National Fire Danger Rating System (NFDRS)

• Canadian Forest Fire Weather Index System (FWI)

Canadian Forest Fire Weather Index System

The higher the values, the more intense the fire!

FuelMoisture Codes

FireBehaviorIndices


• Calculation of FWI parameters begins 3 days after either:

– Final snow melt

– Noon temperatures reach 54o F (12o C)

• Calculation of today’s values starts with yesterday’s, then factors in 24-hour (noon-noon) weather


FuelMoisture Codes

FireBehaviorIndices

Wind speed

TemperatureRelative humidity

Rain

TemperatureRain

FireWeatherObservations

TemperatureRelative humidity

Wind speedRain

Target Values for UnderburningFuel moisture codes: FFMC 90-95 DMC 15-30 DC 70-100Fire behavior indices: ISI 6-10 BUI <50 FWI 10-15

Target Values for UnderburningFuel moisture codes: FFMC 90-95 DMC 15-30 DC 70-100Fire behavior indices: ISI 6-10 BUI <50 FWI 10-15

Target Values for UnderburningFuel moisture codes: FFMC 90-95 DMC 15-30 low intensity fire DC 70-100Fire behavior indices: ISI 6-10 BUI <50 manageable behavior FWI 10-15

Target Values for UnderburningFuel moisture codes: FFMC 90-95 DMC 15-30 low intensity fire DC 70-100Fire behavior indices: ISI 6-10 BUI <50 manageable behavior FWI 10-15

FFMC 90-95DMC 15-30DC 70-100

ISI 6-10BUI <50FWI 10-15

FFMC 90-95DMC 15-30DC 70-100

ISI 6-10BUI <50FWI 10-15

Type of fire: low-intensity surfaceFuel type: C5 red & white pineFireline weather observations: temperature 80-84oF relative humidity 32-34% wind speed <2; gusts to 5 mph days since rain 5

10 May 1991

Fuel moisture codes: FFMC 90.5 DMC 23 DC 76Fire behavior indices: ISI 6.5 BUI 26 FWI 11.6

You’ve got to have a PLANand

you’ve got to be ready to GO…NOW!

The Plan• Burn prescription written• Pre-burn site treatments completed• Equipment designated & ready• Personnel identified & trained• Approvals & permits in hand• Authorities & interested parties identified &

notified*• Latest forecasts checked*

* Day before & day of burn

FOR 406

ContinuedContinued

The Plan• Burn prescription written• Pre-burn site treatments completed• Equipment designated & ready• Personnel identified & trained• Approvals & permits in hand• Authorities & interested parties identified &

notified*• Latest forecasts checked*

* Day before & day of burn

FFMC 90-95DMC 15-30DC 70-100

ISI 6-10BUI <50FWI 10-15

FFMC 90-95DMC 15-30DC 70-100

ISI 6-10BUI <50FWI 10-15

2-3 weeks

Ignition Devices

Ignition Devices

• Hand-held/ground-based

– Drip torch

– Propane torch

– Fire fuse (flare)

– Flame thrower

Drip torch fuel:

3:1 or 3:2Diesel/gasoline

Ignition Devices

• Aerial

– Helitorch– Delayed aerial ignition device

(“ping-pong balls”)

Helitorch

Ignition Devices• Lightning

Ignite a test fire first!Ignite a test fire first!

Ignition Techniques

• Backfire (backing fire)– Least intense & most predictable

– Short flame lengths

– Narrow burning zone

– Slow rate of spread; burns deep

– Low smoke output

Ignition Techniques

• Backfire WIN

D

Ignition Techniques

• Headfire (heading fire)– Most intense & unpredictable

– Long flame lengths

– Wide burning zone

– Fast rate of spread; burns shallow

– High smoke output

Ignition Techniques

• Strip headfire

WIN

D

Distance between strips controls intensity

Ignition Techniques

• Spotfire– Intensity intermediate between back &

head fires

– Useful in shifting winds

– Spots merge to form a strip head fire

– What you get using a DAID

Ignition Techniques

• Spotfire

WIN

D

Distance between spots controls intensity

Ignition Techniques• Flankfire (flanking fire)

– Intensity intermediate between back & head fires

– Fire spreads at right angle to wind– Limited to steady wind conditions– Requires careful crew coordination– Used primarily for securing flanks of back

or head fires

Ignition Techniques

• Flankfire WIN

D

Headfire

Fla

nkfir

eBackfire

Wind

Smoke ManagementSmoke Management

Principles of smoke management

• Have clear, defensible objectives• Comply with local pollution regulations• Notify local fire & law enforcement officials,

nearby residents, & adjacent landowners• Obtain the best available weather forecasts• Don’t burn under highly stable conditions• Burn during midday; avoid night burns• Use caution near, upwind, or up-drainage of

smoke sensitive areas

Principles of smoke management(continued)

• Use test fire to estimate smoke output & behavior

• Use backing fires if feasible

• Burn in small blocks if dispersion marginal

• Do not burn when fuel moisture high

• Don’t burn organic soils

• Mop-up along roads first

• Have an emergency plan!

Karner blue butterflyENDANGERED

Gopher tortoiseTHREATENED

Kirtlands warblerENDANGERED

Economics

Economics

Miller Lumber Co.

Those who regularly work with fire develop a profound respect for its tendency to surprise the unwary.

G.S. Beebe & P.N. Omi

Those who regularly work with fire develop a profound respect for its tendency to surprise the unwary.

G.S. Beebe & P.N. Omi

Mack Lake FireHuron National Forest May 5, 1980

24,000+ acres(20,000 in first 6 hours)

One firefighter killed44 homes & structuresdestroyed

Cerro Grande FireLos Alamos, NM May 4-11, 2000

45,000+ acres 235 homes destroyed Los Alamos National Laboratory threatened

A CAREFUL MATCH … RESTORES!

Partners in promoting responsible prescribed fire

for 406

Documents

prescribed firerainfallweather

weather fuel moisture

fuel sticks

low risk conditions10

weather index systemthe

stand direction

predefined weather conditions

controls woody understorywhy