FOR 406
Harvest
Regenerate
Tend
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
Pines
Western larch
Douglas-fir
Giant sequoia
Oaks
Eucalyptus
“Fire and life, in brief, form a
necessary kind of symbiosis.”
Stephen Pyne
Sparkey
WILD
Remember,
only you
can ignite a
prescribed
fire!
Healthy Forests Restoration Act 2003
A fire is not a
fire…
Surface Fire
Ground Fire
Crown Fire
Frontal Fire Intensity
I (kW m-1) = 2.598 L2.174
I (kW m-1) = 300 L2
WIND
~1.0 m
I = 300 kW m-1
~0.5
m Intensity
Low
I = 58 kW m-1
~0.5 m
I = 75 kW m-1
Low Intensity
~91 m
I = 2,484,300 kW m-1
High Intensity
<1.0 m (3 feet)
Why use prescribed fire?
• Reduces hazardous fuels
Why use prescribed fire?
• Controls woody understory
Why use prescribed fire?
• Controls woody understory
Why use prescribed fire?
• Stimulates natural regeneration & increases
diversity of ground flora
Why use prescribed fire?
• Improves wildlife habitat & livestock forage
Why use prescribed fire?
• 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 settlement) ecological process
Why use prescribed fire?
• Enhances aesthetics & improves access
Why use prescribed fire?
• Watch it burn!
Weather
• Fuel moisture
• Fire behavior
Weather
Good forecasts
are essential!
Weather for prescribed fire
• Wind
–
–
–
–
Speed & direction steady
5 mph or less in the stand
Direction more important than speed
Interacts with topography
Weather for prescribed fire
• 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%
RH
M
N
M
Weather for prescribed fire
• Temperature
– <90o F (35o C)
– Lethal temperature for plant tissue
~145o F
– High temperature dry fuels quickly
Weather for prescribed fire
• Rainfall
Weather for prescribed fire
• Airmass stability
– Resistance of atmosphere to vertical
movement
Weather for prescribed fire
• Airmass stability—unstable
– low resistance to vertical movement (large
decrease in temperature with altitude)
Weather for prescribed fire
• Airmass stability—stable
– high resistance of to vertical movement
(small decrease in temperature with
altitude)
Mixing height
2000-6500 ft agl
Transport windspeed
10-20 mph
Weather for prescribed fire
• Frontal activity
- No approaching fronts, esp. cold fronts
L
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
1-hour (fine fuels)
Fuel diameter
<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)
Fine-fuel moisture & loading
•
•
•
•
Influenced by all the elements of weather
Fuel time lags
8-10% low risk conditions
10-15% high risk conditions
Fine-fuel moisture & loading
•
•
•
•
•
Influenced by all the elements of weather
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!
Fuel
Moisture
Codes
Fire
Behavior
Indices
Canadian Forest Fire Weather Index System
• 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 (noonnoon) weather
Canadian Forest Fire Weather Index System
Fire
Weather
Observations
Fuel
Moisture
Codes
Fire
Behavior
Indices
Temperature
Wind
Relative humidity speed
Wind speed
Rain
Temperature
Relative humidity
Rain
Temperature
Rain
Target Values for Underburning
Fuel moisture codes:
FFMC 90-95
DMC 15-30
DC 70-100
Fire behavior indices:
ISI 6-10
BUI <50
FWI 10-15
Target Values for Underburning
Fuel moisture codes:
FFMC 90-95
DMC 15-30
low intensity fire
DC 70-100
Fire behavior indices:
ISI 6-10
BUI <50
manageable behavior
FWI 10-15
FFMC 90-95
DMC 15-30
DC 70-100
ISI 6-10
BUI <50
FWI 10-15
10 May 1991
Type of fire: low-intensity surface
Fuel type: C5 red & white pine
Fireline weather observations:
temperature 80-84oF
relative humidity 32-34%
wind speed <2; gusts to 5 mph
days since rain 5
Fuel moisture codes:
FFMC 90.5
DMC 23
DC 76
Fire behavior indices:
ISI 6.5
BUI 26
FWI 11.6
You’ve got to have a PLAN
and
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
Continued
FOR 406
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 90-95
DMC 15-30
DC 70-100
ISI 6-10
BUI <50
FWI 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 3:2
Diesel/gasoline
Ignition Devices
• Aerial
– Helitorch
– Delayed aerial ignition device
(“ping-pong balls”)
Helitorch
DAID
Ignition Devices
• Lightning
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
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
Distance
between
strips
controls
intensity
WIND
• Strip
headfire
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
WIND
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
WIND
• Flankfire
Smoke 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 butterfly
ENDANGERED
Gopher tortoise
THREATENED
Kirtlands warbler
ENDANGERED
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
Mack Lake Fire
Huron National Forest
24,000+ acres
(20,000 in first 6 hours)
May 5, 1980
One firefighter killed
44 homes & structures
destroyed
Cerro Grande Fire
Los Alamos, NM
May 4-11, 2000
45,000+ acres
235 homes destroyed
Los Alamos National Laboratory threatened
A CAREFUL MATCH …
RESTORES!
Sparkey
Partners in promoting responsible prescribed fire