USDA Forest Service

Pacific Southwest Research Station

 
Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Publications and Products

Title: Long-term changes in masticated woody fuelbeds in northern California and southern Oregon, USA

Authors: Reed, Warren P.; Varner, J. Morgan; Knapp, Eric E.; Kreye, Jesse K.

Date: 2020

Source International Journal of Wildland Fire

Abstract:

Mechanical mastication is a fuels treatment that shreds midstorey trees and shrubs into a compacted woody fuel layer to abate fire hazards in fire-prone ecosystems. Increased surface fuel loading from mastication may, however, lead to undesirable fire intensity, long-duration flaming or smouldering, and undesirable residual tree mortality. Two major questions facing fuels managers are: how long do masticated fuels persist, and how does the composition of masticated fuelbeds change over time? To evaluate these changes, we measured 25 masticated sites with a range of vegetation, species masticated and time since treatment (1–16 years) in the western US. Seven of the 25 sites were sampled nearly a decade earlier, providing a unique opportunity to document fuelbed changes. Woody fuel loading ranged from 12.1 to 91.9 Mg ha−1 across sites and was negatively related to time since treatment. At remeasured sites, woody fuel loads declined by 20%, with the greatest losses in 1- and 10-h woody fuels (69 and 33% reductions in mass respectively). Reductions were due to declines in number of particles and reduced specific gravity. Mastication treatments that generate greater proportions of smaller-diameter fuels may result in faster decomposition and potentially be more effective at mitigating fire hazard.

Keywords: decomposition, fire hazard reduction, fuel loading, fuels treatments, timelag, woody fuels

View and print the publication (948.0 KB)

Citation

    Reed, Warren P.; Varner, J. Morgan; Knapp, Eric E.; Kreye, Jesse K. 2020. Long-term changes in masticated woody fuelbeds in northern California and southern Oregon, USA. International Journal of Wildland Fire. https://doi.org/10.1071/WF19156.
Last Modified: June 30, 2020