Category: Ecological Research
Title: Fact Sheet: Effectiveness of Fuel Reduction Treatments: Assessing Metrics of Forest Resiliency and Wildfire Severity after the Wallow Fire, AZ
Author: * Waltz, A.E.M.
Subject: Forest Resiliency, Fire Severity, Fuel Reduction
Abstract: Arizona’s largest wildfire to date, the Wallow Fire, was a human-caused fire ignited on May 29, 2011. By early July, the Wallow Fire had burned across 537,820 acres of forest and montane grasslands in eastern Arizona and western New Mexico, with fire managers reporting unusually extreme fire behavior including crowning patch sizes as large as 25,000 acres and spotting distances greater than 3 miles (Wadleigh 2011). While studies have assessed the effectiveness of preventive fire hazard reduction treatment in protecting society’s priority resources (Martinson and Omi 2013), few studies have examined if fuel reduction treatments contribute to ecosystem resili-ence, or the capacity of a system to absorb perturbation and return to a similar set of structures or processes (Holling 1973). In this study, we defined short-term metrics of resiliency to test the hypothesis that fuel reduction treatments in mixed conifer forests increased a fire-adapted system’s resiliency to uncharacteristically severe wildfire. In addition, we tested the hypothesis that fuel reduction treatments reduced burn severity, thereby in-creasing protection for adjacent human communities. Forest fuel reduction treatments and the Wallow Fire occurred in a mix of ponderosa pine (Pinus ponderosa) and mixed conifer forest types. This experiment focused on treatments occurring in warm/dry mixed conifer, characterized by a co-dominance of ponderosa pine and Douglas fir. Both fuel reduction and restoration objectives in warm/dry mixed conifer for-ests can be met by thinning out small diameter fire-intolerant species (removing ladder fuels) and shifting forest structure and composition to larger-diameter, fire-resistant trees (Evans et al. 2011), moving systems toward historic reference conditions. Reintroducing fire consumes accu-mulated surface fuel and contributes significantly to nutrient cycling, veg-etation composition, and quality wildlife habitat while also increasing re-siliency to wildfire (Evans et al. 2011).
Type: Fact Sheet
Source: ERI - Fact Sheet
Publisher: Ecological Restoration Institute