What is Mastication?

Blog Post created by faithberry Employee on Aug 15, 2016

When I first heard about mastication the first thing that came to mind was chewing something yummy.  In the fire prevention arena mastication is the process of “chewing up” vegetation with machinery.  This is just another means of utilizing a tool to reduce fuels in communities.  I have learned about a variety of types of equipment utilized by communities and agencies to get the job completed.  For those of you who did not get the shiny piece of equipment that you were looking for under your tree, I am including some YouTube™ examples of this type of heavy equipment hard at work.

Image 1
: A masticator hard at work. (source: Fire Science Brief, Issue 47, May 2009)

Video 1: Masticator with reticulating arm working in Virginia City Highlands outside of Reno Nevada.  This type of masticator can be manipulated easily to only chew up certain clumps of vegetation and works well in areas where communities only want to select certain clumps of bushes to be removed and others to remain.

Video 2: A masticator with rubber tracks working in Lake Tahoe California.

Key points of the masticating fuels study were:

  • Mastication combined with prescribed burning results in favorable outcomes in terms of burning goals, including fuel reduction.
  • All mastication treatments added fuel load to the forest floor, but the amounts varied by fuel size class and treatment.
  • Mastication equipment used in this study was successful at thinning non-merchantable trees and there was minimal damage to residual over story trees.
  • Burning after mastication reduced fuel across treatments. Burning after mastication also significantly decreased fuel bed, litter, and duff depth.
  • Mastication treatments lowered fire intensity potential because the likelihood of a forest crown or canopy fire is reduced.
  • Soil heating was relatively low within all mastication treatment units that were burned.
  • Fire following mastication generally supported forest management goals.
  • Average cost was comparable to other fuel treatment methods, and may be more efficient.


Image 2: Mastication: coarse fuels treatment (Left) fine fuels treatment (Right). (Source: Fire Science Brief, Issue 47, May 2009).


If your community is considering utilizing this type of heavy equipment for a fuels reduction project,  first contact your local land management agency regarding environmental compliance requirements.  Some types of heavy equipment may not be utilized close to streams and rivers or in other sensitive plant community areas.  Your state forester can also help you with information about these requirements.  For information vist the National Association of State Foresters website.  For information about Firewise Communities/USA® successes visit this weblink.