Fuel mastication, or the mechanical modification of live and dead surface and canopy biomass, to reduce the potential of extreme fire behavior is becoming the preferred fuel treatment for many fire hazard reduction projects. This is especially true in areas where reducing fuels using prescribed fire is challenging. Much of the research conducted in mixed-conifer ecosystems concerns how fire in masticated fuel beds affects soils, how compressed fuels affect fire behavior, and how mastication methods affect vegetation response. However, little is known about the changes in fuel particle and fuel bed characteristics and properties over time.
To answer these questions, scientists, technicians, and volunteers from the RMRS Fire, Fuel and Smoke Science Program, the RMRS Forest and Woodland Ecosystems Science Program, and the University of Idaho spent the summer and fall of 2014 gathering field data and collecting fuel particles from masticated areas in Idaho, Colorado, New Mexico, and South Dakota. The collection sites were located in mixed-conifer forests from dry to wet climates, and were treated with three distinctly different methods of mastication. Each sample area contains a range of ages of masticated materials that will help determine how fuel particles and fuel bed characteristics change over time.
At 15 sites within the four states, the project team measured fuel bed depths for masticated fuel, duff, and recent litter fall to examine the spatial variation of fuel distribution created during the mastication process. Next, samples were collected from 20 subplots (0.5 m x 0.5 m size) at each site. The samples were transported to the Missoula Fire Sciences Lab, where samples from each site were sorted into shape and size classes to characterize fuel loads and particle characteristics. Subsamples of particles were randomly selected to determine length, width, dry weight, particle density, and surface characteristics. We ground-up particles from the same subsample to examine the chemical content of carbon, nitrogen, lignin, and cellulose. Thirty samples from several sites were characterized in 2013-2014.
For more information, please visit http://firelab.org/project/mastication-mixed-conifer-forests.