A Model-Based Framework to Evaluate Alternative Wildfire Suppression Strategies

Karin Riley,Julie Gilbertson-Day,Joe Scott,Matthew Thompson

doi:10.3390/resources7010004

Abstract

The complexity and demands of wildland firefighting in the western U.S. have increased over recent decades due to factors including the expansion of the wildland-urban interface, lengthening fire seasons associated with climate change, and changes in vegetation due to past fire suppression and timber harvest. In light of these changes, the use of more wildland fire on the landscape could reduce fuels and form barriers to the spread of future fires while performing forest restoration in some areas. However, the risks, costs and benefits of changing fire response strategy have not been quantified. Here, we identify gaps regarding the ability to simulate alternative wildfire suppression strategies, due to a number of factors including limited data collected on fireline construction, as well as synergies between firefighting resources and resource effectiveness. We present a fire management continuum: at one end lies full suppression of all fires under all circumstances, and at the opposite end lies no suppression of any fires regardless of location or time in season, with a wide array of managed fire options falling in between. Next, we demonstrate the proof-of-concept using a stochastic fire simulation model, FSim, to simulate two alternative fire suppression strategies close to opposite ends of this continuum for the Sierra National Forest of California: (1) business-as-usual, which equates to nearly full fire suppression; and (2) full suppression of human-caused fires and no suppression actions on lightning-caused fires. Results indicate that fire management strategy can substantially affect the number of large fires and landscape burn probabilities, both of which were shown to increase under the second scenario. However, temporal feedbacks are expected to play an important role: we show that increases in burned area substantially limit ignition potential and the extent of subsequent fires within the first five to ten years, especially under the second scenario. While subject to current data gaps and limitations in fire modeling, the methodology presented here can be used to simulate a number of alternative fire suppression strategies, including decisions to suppress or not suppress fires based on location, time of season or other factors. This method also provides basic inputs needed to estimate risks, costs and benefits of various alternative suppression strategies in future work. In future work, uncertainties resulting from current limitations in knowledge can be addressed using techniques such as scenario planning in order to provide land managers with a set of possible fire outcomes.

Highlights

Wildland fire management in the United States and elsewhere has increased in complexity commensurate with dramatic shifts in the fire environment due to factors such as changing climate, Resources 2018, 7, 4; doi:10.3390/resources7010004 www.mdpi.com/journal/resourcesResources 2018, 7, 4 land use and population [1,2,3,4]
We present results regarding the observed fire record of the study area and of two alternative fire suppression strategies from nearly opposite ends of the fire management continuum
In the observed record of fires occurring in the study area between 1992 and 2013, the vast majority of area was burned by large fires (>100 ha)

Summary

Introduction

Resources 2018, 7, 4 land use and population [1,2,3,4] These shifts produce continued if not growing concerns over escalating fire suppression costs, losses of highly valued resources including homes, and firefighter fatalities (e.g., [5,6]). The legacy of past management practices contributes to the problem, since aggressive fire suppression produces increased fuel loading and continuity that makes future fires resistant to control, a syndrome known as the fire paradox [9,10,11,12,13]. Mechanical treatment alone is insufficient to reduce fuels without the use of prescribed fires [20], is limited in spatial scope compared to the scale of many wildfires [18,21] and is constrained by practical factors including access in many areas [22,23]. An increasing role exists for using unplanned ignitions to manage fuels in selected areas and under selected conditions [24]

Methods

Results

Discussion

Conclusion