Skip to main content

Resource Catalog


Type: Report
Author(s): Nicole M. Vaillant; Alicia L. Reiner; Josephine A. Fites-Kaufman
Publication Date: 2009

Due to increases in tree density and hazardous fuel loading in Sierra Nevada forests, land management is focusing on fuel reduction treatments to moderate the risk of catastrophic fire. Fuel treatments involving mechanical and prescribed fire methods can reduce surface as well as canopy fuel loads. Mastication is a mechanical method which shreds smaller trees and brush onto the surface fuel layer. Little data exists characterizing fuel beds after mastication or mastication/prescribed burn treatments nor the associated fire behavior or effects of these fuel beds. The purpose of this study is to provide land managers with information on fuel characteristics, potential fire behavior and tree mortality associated with mastication and mastication/prescribed burn treatments. This project focused on three types of treatments, mastication, mastication plus prescribed burning and mastication plus prescribed burning after fuels were 'pulled-back' from the boles of trees. Fuel characteristics and tree mortality data were gathered before and after treatments in a 25-year old ponderosa pine (Pinus ponderosa C. Lawson) plantation. In addition to surface fuel characteristics and tree data collection, bulk density samples were gathered for masticated material. Fire behavior measurements were gathered during the prescribed burn treatment using video cameras, thermocouples and passive flame height sensors. Potential fire behavior estimates using 90th and 97th percentile weather, similar to wildfire conditions, were derived using FMAPlus along with post-treatment fuel data. Total masticated fuel load prior to fire treatment ranged from 25.9 to 42.9 Mg ha^-1, and the bulk density of masticated fuel was 125 kg m^-3, both within the range found in other studies. Mastication treatment alone showed increases in most surface fuel loads and decreases in canopy fuel loads. Masticated treatment in conjunction with prescribed burning reduced both surface and canopy fuel loads. Rates of spread and flame lengths as predicted with FMAPlus using 90th and 97th percentile weather and post-treatment fuel conditions for masticated plots were higher in masticated than masticated/burned plots. Torching and crowning indices from FMAPlus indicated that higher winds would be necessary to promote torching in plots treated with mastication and prescribed fire and the probability of active crown fire was reduced slightly for all treated plots. Post-treatment tree mortality, as measured in the field at the end of the first growing season, was 38 % for mastication/burn and 28 % for mastication/pull-back/burn treatments. Detailed information on fuel load and structure in mastication treatments will allow for better predictions of fire behavior and fire effects associated with this treatment; allowing managers to make informed decisions regarding mastication as an option for reducing hazardous fuels and enhancement of forest health.

Online Links
Link to this document (335 KB; pdf)
Citation: Vaillant, Nicole; Reiner, Alicia; Fites-Kaufman, Jo Ann. 2009. Red Mountain mastication study - Final Report to the Joint Fire Science Program. JFSP Project No. 05-2-1-30. Sparks, NV: USDA Forest Service, Adaptive Management Services Enterprise Team. 34 p.

Cataloging Information

  • fuel characteristics
  • hazardous fuel reduction
  • mastication
  • potential fire behavior
  • Sequoia National Forest
  • Sierra Nevada
  • tree mortality
JFSP Project Number(s):
  • 05-2-1-30
Record Last Modified:
Record Maintained By: FRAMES Staff (
FRAMES Record Number: 11751