Ecological risk assessment to support fuels treatment project decisions

Risk is a combined statement of the probability that something of value will be damaged and some measure of the damage’s adverse effect. Wildfires burning in the uncharacteristic fuel conditions now typical throughout the Western United States can damage ecosystems and adversely affect environmental conditions. Wildfire behavior can be modified by prefire fuel treatments, thereby reducing risks to firefighters, structures, and ecosystems, but such projects pose their own environmental risks. To support fuels treatment decisions, environmental analysis of alternatives is generally required, including taking no action. How can managers determine whether risks of actively treating fuels are greater than risks posed by no action? The risk-reduction benefits of fuel treatment are often overlooked in decision processes for comparing wildfire effects with and without fuel treatment. To fill the void, a comparative ecological risk assessment conceptual model is presented. Both prefire fuels treatment and postfire events produce sediment that can adversely affect water quality and aquatic organisms. Similarly, both prescribed fire and wildfire can adversely affect air quality. The model’s tradeoff diagram tests a risk management hypothesis: The benefits of restoring natural (historical) fire regimes and native vegetation in a particular location, plus the benefits of reducing the severity of wildfire effects, balance favorably against any adverse effect, either short- or long-term, from fuels treatment. Managers may believe this hypothesis, but policies require environmental analysis to support it. A tradeoff diagram illustrates the conceptual model and graphically replies to the question: Which produces more sediment, wildfire burning under untreated conditions, wildfire burning after fuels are reduced, or the treatments designed to reduce wildfire risks? Similarly: Which situation would produce more fine particulate matter (PM2.5) air pollution? Tradeoff diagrams of such situations may contribute to sustainable resource management decisions by improving communications between risk assessors, public agency managers, and interested nongovernmental parties.