All presentation of Test 2 fire management

• Rose (time lapsed)


  Measure of energy released on a specific area
• Factors determining energy release


  • Fuel loading
  • Fuel moisture
  • Heat required to reduce moisture to cause combustion
  • Slope
  • Wind speed
  • Fuel compactness
  • Fuel arrangement
• Extreme fire behaviour


  • Results from combination of environmental factors
  • Available fuels
  • Wind
  • Low fuel moisture
  • Stability
  • Weather
• Extreme fire behaviour


  1. High spread rate

  2. Intense burning

  3. Crown fires

  4. Spotting
• Crown fire development


  • Crown closure
  • Stagnation of smoke
  • Torching
  • Spotting
  • Smoke columns
• Wind driven fire


  • Unpredictable spread in all directions
  • High spread rate
  • Short range spotting
  • Sheared smoke columns
  • Long range spotting
  • Smoke rises up
• Smoke colour


  • White smoke - dry fuel
  • Black smoke - living fuel
  • Park smoke - fast spreading fire
• Analyzing extreme fire behaviour

  1. Analyzing searing external

  2. Fuel bed

  3. Type of embers

  4. Number of embers

  5. Gusty wind

  6. Atmospheric instability

  7. Vortices

  8. Intense heat from fire
• Wind driven fire

  • Spotting occurs in front of the fire
  • Fire spread can be predicted
• Plume driven fire


  • Updraft wind forces are stronger than wind force
  • Fire development is unpredictable, spotting occurs in all directions
• Aspect

  • Southern aspect has lower temperature, lowest rate of spread
  • Northern aspect has higher temperature, faster rate of spread
  • Easterly aspect fuels are transitional, first to cool in afternoon
  • Westerly aspect fuels are transitional, last to cool in afternoon
• Slope contributes to pre-heating and ignition by presenting the fuels to the flame front
• Fire will move quicker uphill, slower downhill
• Topography influence on fire behaviour


  • Affects local wind patterns
  • Certain landforms attract lightning ignition
  • Slope affects fuel pre-heating and rate/direction of spread
  • Elevation affects fuel types, loading, curing, and length of fire season
• Slope is the one factor that contributes to runaway fires that we can manage
• Slope positions

  • More fires at base of slope and mid-slope than on top of ridges
  • Rate of spread decreases on the downslope
• Ridges are the best place to construct a break in steep terrain
• Narrow valleys

  • Tend to funnel and accelerate wind on hot days
• Box canyons and chuted valleys


  Steep narrow valleys that funnel and accelerate wind, creating a chimney effect
• Barrier

  Any landscape feature that will obstruct the spread of fire, including breaks in fuel, changes in fuel type, fuel moisture, density, and natural or man-made features
• Influence of aspect on fuel moisture


  • North slope has lowest fuel moisture during the hottest part of the day
  • South slope receives less solar radiation, has higher fuel moisture
• Influence of elevation on fuel moisture


  • As elevation decreases, temperature increases, relative humidity decreases, and fuel moisture decreases
• Fuel size and moisture reaction time


  Larger diameter fuels take longer to gain and lose moisture compared to smaller fuels
• Biomes


  • Fynbos
  • Grassland
  • Savanna
  • Forest
  • Thicket
• Fynbos

  • Coastal fynbos
  • Mountain fynbos
  • Renosterveld
• Components of fynbos


  • Ericoid or heath component
  • Proteoid component
• Types of fuels consumed by fire


  • Aerial fuels (above 2m)
  • Surface fuels (grass, litter, brush up to 2m)
  • Ground fuels (rocks, deep litter, buried logs)
• Fuel characteristics


  • Compactness
  • Fuel load
  • Horizontal continuity
  • Vertical arrangement
  • Chemical content
  • Size and shape
  • Moisture content
  • Fuel temperature
• Moisture exchange rate factors


  • Difference between air and fuel moisture
  • Wind
  • Fuel size
  • Compactness of fuel