unit_8 fuel moisture
TRANSCRIPT
Intermediate Wildland Fire Behavior (S-290)
Intermediate Wildland Fire Intermediate Wildland Fire Behavior (SBehavior (S--290)290)
UNIT 8Fuel Moisture
UNIT 8UNIT 8Fuel MoistureFuel Moisture
Unit 8: Fuel MoistureUnit 8: Fuel MoistureUnit 8: Fuel MoistureObjectives:Objectives:Objectives:Name the five stages of vegetative development of live fuels, and give the average percent moisture content of each.Describe the relationships among relative humidity, wind, and moisture content of fine and large fuels.Explain how the amount and duration of precipitation and soil moisture affect moisture content of fine and large fuels.
Name the five stages of vegetative Name the five stages of vegetative development of live fuels, and give the development of live fuels, and give the average percent moisture content of each.average percent moisture content of each.Describe the relationships among relative Describe the relationships among relative humidity, wind, and moisture content of fine humidity, wind, and moisture content of fine and large fuels.and large fuels.Explain how the amount and duration of Explain how the amount and duration of precipitation and soil moisture affect precipitation and soil moisture affect moisture content of fine and large fuels.moisture content of fine and large fuels.
Unit 8: Fuel MoistureUnit 8: Fuel MoistureUnit 8: Fuel MoistureObjectives (cont’d) :Objectives Objectives (cont(cont’’d)d) ::Define the fuel moisture timelag concept and its value to firefighters and fire managers.Describe how fuel moisture is determined for dead fuels in each of the four timelagcategories.Define moisture of extinction, how it varies in natural fuel complexes, and how it affects wildland fire ignition and spread.
Define the fuel moisture Define the fuel moisture timelagtimelag concept and concept and its value to firefighters and fire managers.its value to firefighters and fire managers.Describe how fuel moisture is determined for Describe how fuel moisture is determined for dead fuels in each of the four dead fuels in each of the four timelagtimelagcategories.categories.Define moisture of extinction, how it varies in Define moisture of extinction, how it varies in natural fuel complexes, and how it affects natural fuel complexes, and how it affects wildlandwildland fire ignition and spread.fire ignition and spread.
Unit 8: Fuel MoistureUnit 8: Fuel MoistureUnit 8: Fuel MoistureObjectives (cont’d) :Objectives Objectives (cont(cont’’d)d) ::Determine fuel moisture contents for dead 1-hour timelag fuels from fuel moisture tables during daylight conditions.
Determine fuel moisture contents for dead 1Determine fuel moisture contents for dead 1--hour hour timelagtimelag fuels from fuel moisture tables fuels from fuel moisture tables during daylight conditions.during daylight conditions.
Natural Fuel SituationsNatural Fuel Situations
Fuel Moisture ContentFuel Moisture Content
Amount of water in a fuel, expressed as a percent of the oven dry weight of that fuel
Amount of water in a fuel, Amount of water in a fuel, expressed as a percent of the expressed as a percent of the oven dry weight of that fueloven dry weight of that fuel
Living FuelsLiving Fuels
LIVE FUELS
HERBACEOUS
WOODY
ANNUALS
PERENNIALS
CONIFEROUS
DECIDUOUS
LIVE
&DEADFUELS
LIVE
&DEADFUELS
Annual Tread of Jack Pine Foliar Moisture
Annual Tread of Jack Pine Foliar Moisture
0
50
100
150
200
250
300
March April May June July August Sept Oct
New Foliage Old Foliage
Live Fuel Moisture ContentLive Fuel Moisture Content
Stage of vegetative development moisture content
Percent
Fresh foliage, annuals developing, early in growing cycle. 300
Maturing foliage, still developing with full turgor. 200
Mature foliage, new growth complete and comparable toolder perennial foliage.
100
Entering dormancy, coloration starting, some leaves mayhave dropped from stem.
50
Completely cured. 30 Treat as dead fuel
STRAWSTRAW
PURPLEPURPLE
GREENGREEN
0
50
100
150
200
250
MO
IST
UR
E C
ON
TE
NT
(%)
0
50
100
150
200
250
MO
IST
UR
E C
ON
TE
NT
(%)
Moisture Content Changes in Cheatgrass
Moisture Content Changes in Cheatgrass
SPRINGSPRING SUMMERSUMMER
3030
LIVING
TRANSITION
DEAD
Live Fuel Moisture (Sagebrush)Muskrat Springs -- Salt Lake District
Year
1996 1997 1998 1999
Two-Week Period Ending1/17
2/143/7
3/214/4
4/185/2
5/165/30
6/136/27
7/117/25
8/88/22
9/59/19
10/310/17
10/3111/14
12/110
50
100
150
200
250
Live Fuel Moisture (Juniper)Muskrat Springs -- Salt Lake District
Year
1996 1997 1998 1999
Two-Week Period Ending1/17
2/143/7
3/214/4
4/185/2
5/165/30
6/136/27
7/117/25
8/88/22
9/59/19
10/310/17
10/3111/14
12/110
30
60
90
120
150
Moisture Exchange in WildlandFuels
Moisture Exchange in WildlandFuels
GROUND MOISTUREGROUND MOISTURE
PRECIPITATION & DEWPRECIPITATION & DEW
RELATIVE HUMIDITYRELATIVE HUMIDITY
EVAPORATIONEVAPORATIONEVAPORATIONEVAPORATION
Equilibrium Moisture ContentEquilibrium Moisture Content
Environmental Factors Influencing Fuel MoistureEnvironmental Factors
Influencing Fuel MoistureNIGHTCLOUDSCANOPY
NIGHTCLOUDSCANOPY
Environmental Factors Influencing Fuel MoistureEnvironmental Factors
Influencing Fuel MoistureNIGHTCLOUDSCANOPY
NIGHTCLOUDSCANOPY
ASPECTSLOPEASPECTSLOPE
Environmental Factors Influencing Fuel MoistureEnvironmental Factors
Influencing Fuel MoistureNIGHTCLOUDSCANOPY
NIGHTCLOUDSCANOPY
ASPECTSLOPEASPECTSLOPE
SOLARRADIATIONSOLARRADIATION
ELEVATION
UNSHADED
SHADE
WIND
PRECIPITATION
FUELMOISTUREFUELMOISTURE
TEMPERATURERELATIVE
HUMIDITY
TEMPERATURERELATIVE
HUMIDITY
Shaded vs. Unshaded Effectson Fuel Temperatures
Shaded vs. Unshaded Effectson Fuel Temperatures
85º85º
85º85ºAIR TEMPERATUREAIR TEMPERATURE
3%3%8%8%
FUEL MOISTUREFUEL MOISTURE
SURFACE TEMPSURFACE TEMP110º110º 160º160º
Aspect Affects Fuel MoistureAspect Affects Fuel Moisture
0
5
10
15
0:00
6:00
12:00
18:00
Time of Day
Moi
stur
e C
onte
nt (%
)
0
5
10
15
0:00
6:00
12:00
18:00
Time of Day
Moi
stur
e C
onte
nt (%
)
EAST SLOPEEAST SLOPE
NORTH SLOPENORTH SLOPE
SOUTH SLOPESOUTH SLOPE
WEST SLOPEWEST SLOPE
0
1000
2000
3000
J F M A M J J A S O N D
MONTH
Btu
s/A
ve D
ays/
sq ft
0
1000
2000
3000
J F M A M J J A S O N D
MONTH
Btu
s/A
ve D
ays/
sq ft
Solar Heating Received at Boise, Idaho
Solar Heating Received at Boise, Idaho
EEEE
E = EQUINOXE = EQUINOX
Elevation Affects Fuel Moisture (Daytime)
Elevation Affects Fuel Moisture (Daytime)
1000 FEET1000 FEET
2000 FEET2000 FEET
3000 FEET3000 FEET
4000 FEET4000 FEET
5000 FEET5000 FEET
ELEVATION
6000 FEET
ELEVATION
6000 FEET
TEMPTEMP RHRHFUEL
MOISTUREFUEL
MOISTURE
69 º69 º 39%39% 8%8%
73 º73 º 35%35% 7%7%
76 º76 º 31%31% 6%6%
80 º80 º 27%27% 5%5%
83 º83 º 25%25% 5%5%
87 º87 º 22%22% 4%4%
Slope Percent Affect Solar HeatingSlope Percent Affect Solar Heating
WINDSWINDSWINDS
0
5
10
15
20
25
30
35
0 2 4 6 8 10 12 14 16
HOURS OF CONTINUOUS PRECIPITATION
FUE
L M
OIS
TUR
E C
ON
TEN
T (%
)
1-Hour10-Hour100-Hour
0
5
10
15
20
25
30
35
0 2 4 6 8 10 12 14 16
HOURS OF CONTINUOUS PRECIPITATION
FUE
L M
OIS
TUR
E C
ON
TEN
T (%
)
1-Hour10-Hour100-Hour
Duration of Precipitation & Fuel Moisture
Duration of Precipitation & Fuel Moisture
Timelag and Fuel Size RelationshipsTimelag and Fuel Size Relationships
Dead Fuel Timelag CategoriesDead Fuel Timelag Categories
TIMELAG DIAMETER (inches)
1-Hour 0 to
10-Hour to 1
100-Hour 1 to 3
1000-Hour 3 to 8
Reaction Time of Fuels to Wetting & Drying
Reaction Time of Fuels to Wetting & Drying
MO
IST
UR
E C
ON
TE
NT
MO
IST
UR
E C
ON
TE
NT
DAYS AFTER PRECIPITATIONDAYS AFTER PRECIPITATIONPRECIPITATIONPRECIPITATION
DAYBEFORE
DAYBEFORE
LASTDAY OFLAST
DAY OF11 22 33 44 55 66 77
12” LOG12” LOG
½” STICKS½” STICKS
Daily Relationship of Relative Humidity to Fine Dead Fuel Moisture
Daily Relationship of Relative Humidity to Fine Dead Fuel Moisture
12 PM12 PM 6 AM6 AM NOONNOON 6 PM6 PM 12 PM12 PM00
REL
ATI
VE H
UM
IDIT
Y &
MO
ISTU
RE
CO
NTE
NT
PER
CEN
T
REL
ATI
VE H
UM
IDIT
Y &
MO
ISTU
RE
CO
NTE
NT
PER
CEN
T
RELATIVE HUMIDITYRELATIVE HUMIDITY
MOISTURE CONTENTMOISTURE CONTENT
Methods for Determining Fuel Moisture Content
Methods for Determining Fuel Moisture Content
Determining Fuel Moisture Content in Fine Dead Fuels (1-Hour Timelag)Determining Fuel Moisture Content in Fine Dead Fuels (1-Hour Timelag)
Dry Bulb TemperatureRelative Humidity
Dry Bulb TemperatureRelative Humidity
MonthShaded or UnshadedTime of DaySite LocationAspectSlope
MonthShaded or UnshadedTime of DaySite LocationAspectSlope
REFERENCE FUELMOISTURE (RFM)REFERENCE FUELMOISTURE (RFM)
FUEL MOISTURECORRECTION (FMC)FUEL MOISTURECORRECTION (FMC)
ADJUSTED FINE DEADFUEL MOISTURE (FDFM)ADJUSTED FINE DEADFUEL MOISTURE (FDFM)
Table 1Reference Fuel Moisture (Day Time 0800-1959)
Input Line 6
Table 1Reference Fuel Moisture (Day Time 0800-1959)
Input Line 6
Go to Tables 2,3, or 4 for CorrectionsGo to Tables 2,3, or 4 for Corrections
Fine Dead Fuel Moisture WorksheetFine Dead Fuel Moisture Worksheet
Table 2Fine Dead Fuel Moisture Content Corrections
(Day Time 0800-1959) May, June, JulyInput Line 13
Table 2Fine Dead Fuel Moisture Content Corrections
(Day Time 0800-1959) May, June, JulyInput Line 13
Note: B = 1,000 to 2,000 feet below siteL = ± 1,000 feet of site locationA = 1,000 to 2,000 feet above site
Note: B = 1,000 to 2,000 feet below siteL = ± 1,000 feet of site locationA = 1,000 to 2,000 feet above site
Table 3Fine Dead Fuel Moisture Content Corrections
(Day Time 0800-1959) Feb, March, April / Aug, Sept, OctInput Line 13
Table 3Fine Dead Fuel Moisture Content Corrections
(Day Time 0800-1959) Feb, March, April / Aug, Sept, OctInput Line 13
Note: B = 1,000 to 2,000 feet below siteL = ± 1,000 feet of site locationA = 1,000 to 2,000 feet above site
Note: B = 1,000 to 2,000 feet below siteL = ± 1,000 feet of site locationA = 1,000 to 2,000 feet above site
Table 4Fine Dead Fuel Moisture Content Corrections
(Day Time 0800-1959) November, December, JanuaryInput Line 13
Table 4Fine Dead Fuel Moisture Content Corrections
(Day Time 0800-1959) November, December, JanuaryInput Line 13
Note: B = 1,000 to 2,000 feet below siteL = ± 1,000 feet of site locationA = 1,000 to 2,000 feet above site
Note: B = 1,000 to 2,000 feet below siteL = ± 1,000 feet of site locationA = 1,000 to 2,000 feet above site
Temperature and Humidity SelectionTemperature and Humidity Selection
Above Site (A)Above Site (A)
Site Location (L)Site Location (L)
Below Site (B)Below Site (B)
1,000 feet1,000 feet
1,000 feet1,000 feet
0 feet0 feet
2,000 feet2,000 feet
2,000 feet2,000 feet
Solution to Exercise 2, Number 3a & 3bFine Dead Fuel Moisture Worksheet
Solution to Exercise 2, Number 3a & 3bFine Dead Fuel Moisture Worksheet
Example of B, L, A ValuesFine Dead Fuel Moisture Worksheet
Example of B, L, A ValuesFine Dead Fuel Moisture Worksheet
FIRE SEVERITY RELATED TO RELATIVE HUMIDITY AND FUEL MOISTURE CHARTFIRE SEVERITY RELATED TO RELATIVE HUMIDITY AND FUEL MOISTURE CHART
R.H.(%)
1-HRF.M. %
10- HRF.M. %
Relative ease of chance ignition and spotting,general burning con ditions
>60 >20 >15 Very little ignition; some spotting may occur withwinds above 9 mph
45-60 15-19 12-15Low ignition hazard--campfires become dangerous;glowing brands cause ignition when relativehumidity is <50 percent
30-45 11-14 10-12 Medium ignitability--matches become dangerous;easy burning conditions
26-40 8-10 8-9High ignition hazard--matches always dangerous;occasional crowning, spotting caused by gustywinds; moderate burning conditions
15-30 5-7 5-7
Quick ignition, rapid buildup, extensive crowning;any increase in wind causes increased spotting,crowning, loss of control; fire moves up bark oftrees igniting aerial fuels; long distance spotting inpine stands; dangerous burning conditions
<15 <5 <5
All sources of ignition dangerous; aggressiveburning, spot fires occur often and spread rapidly,extreme fire behavior probable; critical burningconditions
R.H.(%)
1-HRF.M. %
10- HRF.M. %
Relative ease of chance ignition and spotting,general burning con ditions
>60 >20 >15 Very little ignition; some spotting may occur withwinds above 9 mph
45-60 15-19 12-15Low ignition hazard--campfires become dangerous;glowing brands cause ignition when relativehumidity is <50 percent
30-45 11-14 10-12 Medium ignitability--matches become dangerous;easy burning conditions
26-40 8-10 8-9High ignition hazard--matches always dangerous;occasional crowning, spotting caused by gustywinds; moderate burning conditions
15-30 5-7 5-7
Quick ignition, rapid buildup, extensive crowning;any increase in wind causes increased spotting,crowning, loss of control; fire moves up bark oftrees igniting aerial fuels; long distance spotting inpine stands; dangerous burning conditions
<15 <5 <5
All sources of ignition dangerous; aggressiveburning, spot fires occur often and spread rapidly,extreme fire behavior probable; critical burningconditions
Unit 8: Fuel MoistureREVIEW
Unit 8: Fuel MoistureUnit 8: Fuel MoistureREVIEWREVIEW
Objectives:Objectives:Objectives:Name the five stages of vegetative development of live fuels, and give the average percent moisture content of each.Describe the relationships among relative humidity, wind, and moisture content of fine and large fuels.Explain how the amount and duration of precipitation and soil moisture affect moisture content of fine and large fuels.
Name the five stages of vegetative Name the five stages of vegetative development of live fuels, and give the development of live fuels, and give the average percent moisture content of each.average percent moisture content of each.Describe the relationships among relative Describe the relationships among relative humidity, wind, and moisture content of fine humidity, wind, and moisture content of fine and large fuels.and large fuels.Explain how the amount and duration of Explain how the amount and duration of precipitation and soil moisture affect precipitation and soil moisture affect moisture content of fine and large fuels.moisture content of fine and large fuels.
Unit 8: Fuel MoistureREVIEW
Unit 8: Fuel MoistureUnit 8: Fuel MoistureREVIEWREVIEW
Objectives (cont’d) :Objectives Objectives (cont(cont’’d)d) ::Define the fuel moisture timelag concept and its value to firefighters and fire managers.Describe how fuel moisture is determined for dead fuels in each of the four timelagcategories.Define moisture of extinction, how it varies in natural fuel complexes, and how it affects wildland fire ignition and spread.
Define the fuel moisture Define the fuel moisture timelagtimelag concept and concept and its value to firefighters and fire managers.its value to firefighters and fire managers.Describe how fuel moisture is determined for Describe how fuel moisture is determined for dead fuels in each of the four dead fuels in each of the four timelagtimelagcategories.categories.Define moisture of extinction, how it varies in Define moisture of extinction, how it varies in natural fuel complexes, and how it affects natural fuel complexes, and how it affects wildlandwildland fire ignition and spread.fire ignition and spread.
Unit 8: Fuel MoistureREVIEW
Unit 8: Fuel MoistureUnit 8: Fuel MoistureREVIEWREVIEW
Objectives (cont’d) :Objectives Objectives (cont(cont’’d)d) ::Determine fuel moisture contents for dead 1-hour timelag fuels from fuel moisture tables during daylight conditions.
Determine fuel moisture contents for dead 1Determine fuel moisture contents for dead 1--hour hour timelagtimelag fuels from fuel moisture tables fuels from fuel moisture tables during daylight conditions.during daylight conditions.