Evaluation of a 10-h fuel stick and a moisture meter for measuring fine dead fuel moisture and response times

Background Accurate estimates of fine dead fuel moisture content (FMC) are critical for assessing bushfire risk. Aims This study aimed to evaluate the ability of the Campbell Scientific 10-h fuel stick and the Wiltronics Fine Fuel Moisture Meter for estimating fine dead FMC. Methods Equilibrium FMC of eucalyptus leaf litter and cured Kangaroo grass was measured under varying humidities in controlled laboratory experiments using a 10-h fuel stick and a Wiltronics meter, and compared against oven-dried FMC. Response times of 1- and 10-h fuel to environmental changes were also investigated. Key results The 10-h fuel stick underestimated fine FMC under dry conditions. Its response times were approximately 20 h (adsorption) and 9 h (desorption), while 1-h fuel showed faster drying responses (2.84 h for leaf litter and 2.64 h for grass). The Wiltronics meter demonstrated better accuracy at lower FMC levels (9–16%) but underestimated FMC at higher humidity (>80%). Conclusions Both tools potentially have limitations for wildfire applications. The 10-h fuel stick may need calibration, especially in changing conditions. The Wiltronics moisture meter, while underestimating FMC at higher humidity, is effective for prescribed burning. Implications These findings offer insights into the effectiveness of different FMC estimation methods, which are pivotal for fire management.