Bushfire behaviour is influenced by many factors including temperature, relative humidity (RH), forest type, fuel quantity and fuel dryness, topography and even slope. Wind has a dominant effect on the Rate of Spread (ROS), as well as fire size, shape and direction. Temperature and relative humidity have major impacts on fuel dryness and therefore upon the availability of fuel for combustion. A thermo-hygrograph measures and records both temperature and humidity. It produces a continuous record by drawing ink traces on a paper chart held in revolving cylinder. Humidity is measured by shortening or lengthening of a bundle of specially treated human hair. Temperature is measured by means of a laminated bi-metal strip of temperature-sensitive metals which bend differentially with temperature change. The recording drum is driven by clockwork which may be geared for rotation intervals of daily, weekly or monthly periods. This particular instrument is a seven-day recorder. Serial number 10186 which probably dates from about 1960. The chart indicates it was last used in March 1979.Used for bushfire research.Clockwork Thermo-hygrographCasella London 10186 Made in England Research Branch. Forests Commission Orbostbushfire, forests commission victoria (fcv), forest measurement

Used to prepare fuel samples to measure their moisture content. Representative samples of fine fuel such as bark, leaves, twigs etc were minced first through a course mincing plate, then a fine plate and the moisture content measured with a Speedy moisture meter or other device. 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. Spong No 10 food mincerforests commission victoria (fcv), bushfire, forest measurement

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. Adaption of a timber moisture meter made by the FCV radio lab to measure fuelforests commission victoria (fcv), bushfire, forest measurement