Wiltronics Research Pty Ltd 20
561 DC1V1
APPENDIX B. A GUIDE TO FUEL MOISTURE CONTENT
AND FIRE BEHAVIOUR.
Eucalypt
Radiata Pine
Fine Fuel
Moisture Content (% ODW)
Indicative Fire Behaviour
(Radiata Pine Fuels)
(Source: Woodman, M. & Rawson, R. (1982), Fire Research Report No. 14)
< 7
Very intense wildfire possible
7 - 10
Elevated dead needles carry fire of high intensity, which is difficult to control.
Surface needles carry fire of moderate to high intensity.
10 - 15
Elevated dead needles carry fire of moderate intensity (e.g. ROS > 1 m/min).
Surface needles easily ignited and carry fire of moderate intensity.
15 - 20
Elevated dead needles easily ignited and carry fire of low intensity (e.g. ROS up to 1 m/min).
Surface needles ignite and carry slow moving fire (e.g. ROS < 0.5 m/min).
20 - 25
Elevated dead needles will ignite and just carry a fire (e.g. ROS < 0.2 m/min).
Surface needles will just ignite and only carry fire with the assistance of wind
25 - 30
Elevated dead needles will just ignite and will carry fire only with the assistance of wind.
Surface needles will not ignite.
(Adapted from: McArthur, A.G. (1962,1967), For. & Timb. Bureau, Leaflets 80, 107)
Surface Fine Fuel
Moisture Content (% ODW)
Indicative Fire Behaviour
(Eucalypt Fuels)
< 4
Fuel extremely dry. Severe spotting, crown fire, uncontrollable.
22 - 28
Litter is wet. Fuel very difficult to ignite. Burning very difficult to sustain.
4 - 6
Litter very dry. Fire behaviour could be severe, spotting likely, possible crown fire.
6 - 9
Litter dry. Conditions may not be suitable for fuel reduction burning, fuel very easy
to ignite, spotting initiated by large firebrands only, but high intensity fire may develop.
16 - 22
Litter is damp. Eucalypt fuel is difficult to ignite. Burning difficult to sustain.
Low intensity fuel reduction burn could be patchy. No spotting.
9 - 13
Litter is reasonably dry. Eucalypt litter easy to ignite. Burning readily sustained.
Fuel reduction may be carried out in light fuels under very mild weather conditions.
Limited spotting from large firebrands.
13 - 16
Litter just moist. Eucalypt fuel moderately easy to ignite. Burning is sustained.
A suitable range for fuel reduction when other conditions, particularly wind, are suitable.
Spotting unlikely.
NOTE 1. Elevated dead needles refer to dead pine needles lodged on branches, vegetation or debris on the forest floor so
that they are well aerated and above the ground.
NOTE 1. Surface needles refer to the top part of the duff layer of dead pine needles. They are more compacted than
elevated dead needles, but better aerated than the underlying part of the duff layer.
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