Historical information

Used to mince fuel samples to measure moisture content

Representative samples of fuel such as bark, leaves, twigs etc were minced and the moisture measured

The availability of fuel to burn depends largely on its moisture content. When it exceeds 20-25% not much will burn, whereas 12-15% is generally ideal for fuel reduction burning, but if the moisture content drops as low as 7-10% virtually everything will ignite, and fire behaviour becomes extreme.

During the afternoon of the Ash Wednesday bushfires on 16 February 1983 fuel moisture contents were recorded at Stawell as low as 2.7%.

Fine fuels like leaves and bark can rapidly absorb moisture after a shower of rain, or from the air when the Relative Humidity (RH) is high, and the temperature is low. Conversely, they can also dry out very quickly.

So even though the overall fuel quantity in the forest doesn’t change, the fine fuel availability can increase rapidly from zero after rain to many tonnes per hectare as the fuel dries out. This can happen over a few hours on hot and windy days. Heavy fuels like logs on the ground take longer to dry out.

Physical description

Battery operated Fuel mincer. Plugs into 12 volt car cigarette lighter socket
Adaption using parts from commercial food processor
Made at Altona as an alternative design to the commercial Spong Mincer
Glass jar to collect sample