Description

Mastication has become a popular fuels treatment in the Western United States, but predicting subsequent fire behavior and effects has proven difficult. Fire behavior and effects in masticated fuelbeds have been more intense and erratic in comparison with model predictions. While various particle or fuelbed characteristics in these fuels may contribute to the inaccuracy of model predictions, an increase in particle surface area to volume ratio by the mastication process may affect moisture dynamics. The prediction of fuel moisture is critical to predicting fire behavior and effects in prescribed fire or wildfire scenarios. Moisture dynamics in masticated fuels is characterized here by analyzing desorption rates in masticated and intact manzanita and compared with pine and maple dowels under laboratory experiments. Preliminary analysis shows that desorption rates are similar in masticated and intact manzanita as well as pine dowels by comparing relative moisture contents throughout desorption as well as by calculating response times using the timelag concept. These results held true both at the particle and fuelbed level, although masticated manzanita and pine dowels were both found to desorb moisture more quickly as individual particles compared to within fuelbeds. Particle density was strongly linked to desorption although it is not fully explored in terms of its significance as compared with other physical properties. Physical and chemical differences due to particle weathering and species differences may play significant roles as well. While this may be some of the first work to address the effects of mastication on moisture dynamics in forest fuels, future work should focus on other aspects where fuelbed or particle characteristics in masticated fuels may influence fire behavior and effects.