Uncertainty and Risk in Wildland Fire Management
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Journal of Environmental Management 92 (2011) 1895e1909 Contents lists available at ScienceDirect Journal of Environmental Management journal homepage: www.elsevier.com/locate/jenvman Review Uncertainty and risk in wildland fire management: A review Matthew P. Thompson*, Dave E. Calkin Rocky Mountain Research Station, USDA Forest Service, PO Box 7669, Missoula, MT 59807, USA article info abstract Article history: Wildland fire management is subject to manifold sources of uncertainty. Beyond the unpredictability of Received 7 June 2010 wildfire behavior, uncertainty stems from inaccurate/missing data, limited resource value measures to Received in revised form guide prioritization across fires and resources at risk, and an incomplete scientific understanding of 20 January 2011 ecological response to fire, of fire behavior response to treatments, and of spatiotemporal dynamics Accepted 11 March 2011 involving disturbance regimes and climate change. This work attempts to systematically align sources of Available online 13 April 2011 uncertainty with the most appropriate decision support methodologies, in order to facilitate cost- effective, risk-based wildfire planning efforts. We review the state of wildfire risk assessment and Keywords: fi Uncertainty and risk management, with a speci c focus on uncertainties challenging implementation of integrated risk fi Risk assessment assessments that consider a suite of human and ecological values. Recent advances in wild re simulation Wildfire management and geospatial mapping of highly valued resources have enabled robust risk-based analyses to inform Decision support planning across a variety of scales, although improvements are needed in fire behavior and ignition occurrence models. A key remaining challenge is a better characterization of non-market resources at risk, both in terms of their response to fire and how society values those resources. Our findings echo earlier literature identifying wildfire effects analysis and value uncertainty as the primary challenges to integrated wildfire risk assessment and wildfire management. We stress the importance of identifying and characterizing uncertainties in order to better quantify and manage them. Leveraging the most appropriate decision support tools can facilitate wildfire risk assessment and ideally improve decision- making. Published by Elsevier Ltd. 1. Introduction aspects of decision-making under uncertainty. Here we review extant approaches to managing uncertainty adopted in the wildfire Wildfire is a global phenomenon, with attendant global investi- management literature, and attempt to systematicallyalign sources of gation into the impacts of wildfires on human life and property, uncertainty with the most appropriate decision support methodol- ecosystems, and other valued resources, and into the factors ogies, in order to facilitate efficient, risk-informed wildfire planning contributing to wildfire occurrence and spread. Managing wildland efforts. Our work therefore examines wildfire risk assessment largely fire is subject to manifold sources of uncertainty. Beyond the through the lens of resource economics and decision science. unpredictability of wildfire behavior, uncertainty stems from inac- Uncertainty is essentially a lack of information; complete igno- curate/missing data, incomplete scientific understanding of ecolog- rance represents one end of the spectrum and perfect information ical response to fire, incomplete scientific understanding of fire (i.e., certainty) the other. Managing uncertainty is of course nothing behavior response to management treatments (suppression, fuel new to fire managers, who have and continue to make decisions with reduction, etc.), and limited resource value measures to guide imperfect information. Where one can express uncertainty quanti- prioritization across fires and resources at risk. Strategic manage- tatively (e.g., modeled as a probability distribution), one can speak in ment is subject to significant additional uncertainty when attempt- terms of managing risk. Objective, repeatable measures of risk can ing to consider the spatiotemporal dynamics of climate change, better inform management (Roloff et al., 2005). Our challenge is to vegetative succession, species migration, and disturbance regimes. better understand the nature of uncertainty, identify where it can be Recognizing that there are various manifestations of uncertainty, integrated into quantitative risk management frameworks, and decision scientists have developed myriad tools to address particular where it cannot, to identify what additional information is necessary to reduce the scope and magnitude of the uncertainty. In this paper we view wildfire management through the lens of * Corresponding author. Tel.: þ1 406 329 3393; fax: þ1 406 329 3487. a widely accepted ecological risk assessment framework (Fairbrother E-mail address: [email protected] (M.P. Thompson). and Turnley, 2005; U.S. Environmental Protection Agency,1998). Risk 0301-4797/$ e see front matter Published by Elsevier Ltd. doi:10.1016/j.jenvman.2011.03.015 1896 M.P. Thompson, D.E. Calkin / Journal of Environmental Management 92 (2011) 1895e1909 assessments are decision support tools that integrate information ultimately chosen, using a coherent framework informs manage- regarding the likelihood and magnitude of resource response to risk ment by facilitating the identification of potential sources of factors, in order to synthesize a conclusion about risk that can inform uncertainty and the quantification of their impact. decision-making (Sikder et al., 2006). Risk assessments inform For the purposes of this paper we adopt the uncertainty strategic, tactical, and operational decision-making, and are used in typology of Ascough et al. (2008), which synthesizes various extant decision support models as developed by operations researchers and characterizations of uncertainty in the environmental decision- other management scientists. In the absence of fire risk assessments, making context. According to this typology, four broad categories of decisions and management are likely to be less effective (Bar uncertainty exist: linguistic uncertainty, variability uncertainty, Massada et al., 2009). The process of evaluating how risk to various knowledge uncertainty, and decision uncertainty. Linguistic resources changes in response to alternative management scenarios uncertainty refers to issues of vagueness, ambiguity, the contextual (including no action) is crucial to risk-informed decision-making dependency of words, evolving definitions, and difficulty in (e.g., Ager et al., 2010a, 2007; O’Laughlin, 2005; Roloff et al., 2005). explaining results. Brugnach et al. (2010) describe ambiguity as Increasingly, wildfire management is being viewed as a form of a source of uncertainty in which there may exist more than one risk management, with a corresponding increase in analytical rigor valid way of understanding the system to be managed, thus leading and alignment with risk management principles. Developing and to alternate problem definitions and solution approaches. In the using wildfire risk assessment models can aid active and preven- wildfire context the term “risk” has been used somewhat loosely, tative forest management decision-making (González et al., 2006). engendering confusion (Chuvieco et al., 2010; Schmoldt, 2001). The literature continues to expand with examples of wildfire risk Hardy (2005), for instance, defines risk as the probability of fire analyses from around the globe (e.g., Atkinson et al., 2010; Dlamini, occurrence, whereas Finney (2005) adopts an actuarial approach, 2010; Kaloudis et al., 2010; Li et al., 2009; Zhijun et al., 2009). defining risk as the probabilistic expectation of net resource value Planning scales for wildfire management range from incident- change in response to fire. For the purposes of this paper we adopt specific to regional/national assessment, and applications include the latter definition, consistent with our risk assessment frame- fire prevention, fire detection, deployment and initial attack work (e.g., Fairbrother and Turnley, 2005) as well as other dispatch, large fire management, and strategic planning and fuel approaches in the forest planning literature (e.g., Gadow, 2000). management (Martell, 2007). Managing fire risk involves analyzing Variability uncertainty refers to the inherent variability that both exposure and effects (i.e., likelihood and magnitude of manifests itself in natural systems. Elsewhere in the literature this potential beneficial/detrimental effects), and then developing uncertainty may have been referred to as external, objective, appropriate management responses to reduce exposure and/or random, or stochastic. The frequency and spatial pattern of ignition mitigate adverse effects (Fairbrother and Turnley, 2005; Finney, locations, or the weather conditions driving extreme fire behavior 2005). Effective management of wildfire risk requires a clear defi- are examples of variability uncertainty. Probabilistic approaches are nition of management objectives, and where multiple objectives most often used to handle variability uncertainty, such as modeling are present, an understanding of relative management priorities. fire occurrence, spread, and/or intensity (e.g., Ager et al., 2010a; The primary aim of this paper is to review the state of wildfire Carmel et al., 2009; Krougly et al., 2009; Bar Massada et al., 2009; risk assessment and management, with a specific focus on uncer- Podur et al., 2009; Wei et al., 2008; Amacher et al., 2005).