Effect of mastication and other mechanical treatments on fuel structure in chaparral

International Journal of Wildland Fire
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Abstract

Mechanical fuel treatments are a common pre-fire strategy for reducing wildfire hazard that alters fuel structure by converting live canopy fuels to a compacted layer of dead surface fuels. Current knowledge concerning their effectiveness, however, comes primarily from forest-dominated ecosystems. Our objectives were to quantify and compare changes in shrub-dominated chaparral following crushing, mastication, re-mastication and mastication-plus-burning treatments, and to assess treatment longevity. Results from analysis of variance (ANOVA) identified significant differences in all fuel components by treatment type, vegetation type and time since treatment. Live woody fuel components of height, cover and mass were positively correlated with time since treatment, whereas downed woody fuel components were negatively correlated. Herbaceous fuels, conversely, were not correlated, and exhibited a 5-fold increase in cover across treatment types in comparison to controls. Average live woody fuel recovery was 50% across all treatment and vegetation types. Differences in recovery between time-since-treatment years 1–8 ranged from 32–65% and exhibited significant positive correlations with time since treatment. These results suggest that treatment effectiveness is short term due to the rapid regrowth of shrubs in these systems and is compromised by the substantial increase in herbaceous fuels. Consequences of not having a full understanding of these treatments are serious and leave concern for their widespread use on chaparral-dominated landscapes.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Effect of mastication and other mechanical treatments on fuel structure in chaparral
Series title International Journal of Wildland Fire
DOI 10.1071/WF14140
Volume 24
Issue 7
Year Published 2015
Language English
Publisher Fire Research Institute
Publisher location Roslyn, WA
Contributing office(s) Western Ecological Research Center
Description 15 p.
First page 949
Last page 963
Online Only (Y/N) N
Additional Online Files (Y/N) N