Estimating Fuel Moisture Response Times From Field Observations

Abstract

The response time of a fuel element is defined in terms of the response to a step change in moisture content, and is not measurable in the field. However the formulation of fine fuel moisture content as a continuous process leads to a simple relationship between the re- sponse time of the fuel and the time lag with respect to a diurnally varying equilibrium moisture content. This time lag is estimable from field data. This method is applied to obtain response times for fine litter in a EucaIyptus forest. The same formulation is applied to the discrete moisture content model of Fosberg and Deeming (1971) which is re-cast and solved as a continuous model.