Using Herbicides to Reduce the Risk of Forest Fires


Wildfire Burning on Forest Floor


Spraying Weeds on Forest Floor

Forest floors can be covered with many weeds that dry out and become a source of fuel
for forest fires. Many weed species dry quickly during drought creating hazardous “flashy” fuels in wildfire situations.  Studies have shown a significant reduction in fire intensity in areas where herbicides are applied to remove weeds. Incorporating herbicides into land management plans helps to decrease fuel loads and reduce the risk of forest fires.

“Exotic annual grasses such as cheatgrass, medusahead, and Ventenata can produce large amounts of fine fuel loads creating favorable conditions for wild fires… Herbicides imazapic and propoxicarbazone sodium have been particularly effective in controlling or suppressing exotic annual grasses, depending on rates and time of application. The main limitation for extensive use of these herbicides, particularly in rangelands, is the cost. However, if the fuel load from exotic annual grasses is reduced, the risk of wild fires will also decrease as a result of the herbicide applications. This could help create lower fire risk sections or corridors in order to protect more sensitive areas such as installations, roadsides, buildings, animal shelters, etc. The cost of herbicide applications for these areas would be compensated by the value of the saved resources and reduction in the cost of controlling frequent wild fires. The use of herbicides would only be justified if a significant reduction of the fuel load is achieved. The objective of this study was to quantify the impact of herbicides and application timings on invasive annual grass fuel load production.

…Although every treatment had an impact on the produced litter, the most significant biomass reduction, 53 percent, was observed with the application of Plateau®.

These preliminary results suggest that herbicides have the potential be used to reduce fuel loads from annual weedy grasses, particularly in recently burned fields.”

Authors: Sbatella, G., and Twelker, S.
Affiliations: Oregon State University
Title: Impact of herbicide applications for exotic annual grass control on fuel load production.
Source: Rangeland Research Reports, available at:


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