Christopher J. Dunn

Temporal fuel dynamics following high-severity fire in dry mixed conifer forests of the eastern Cascades, Oregon, USA

Fire-resilient landscapes require the recurrent use of fire, but successful use of fire in previously burned areas must account for temporal fuel dynamics. We analysed factors influencing temporal fuel dynamics across a 24-year spatial chronosequence of unmanipulated dry mixed conifer forests following high-severity fire. Duff and litter accumulated as bark sloughed from snags and leaves senesced from recovering vegetation, averaging 14.6 Mg ha–1 and 22.1 Mg ha–1 at our 24-year post-fire site, respectively. 1-h fuels increased linearly, averaging 1.1 Mg ha–1 at our 24-year post-fire site, with additions occurring from recovering vegetation. 10-h and 100-h fuels exhibited non-linear temporal trends, with maximum loadings occurring 14 years (3.9 Mg ha–1) and 18 years (10.5 Mg ha–1) post-fire, respectively. 1000-h fuel accumulation slowed after 20 years post-fire (reached 124.6 Mg ha–1), concurrently with ~90% snag fall and fragmentation. Maximum herbaceous fuel loading averaged 0.73 Mg ha–1 at our 5-year post-fire sites, but only averaged 0.02 Mg ha–1 at all sites thereafter. Live shrub biomass accumulation slowed after 21 years post-fire, averaging 14.3 Mg ha–1 at our 24-year post-fire site. Managers can use post-fire temporal fuel dynamics to help facilitate the restoration of fire regimes while mitigating undesirable fire effects.

Towards enhanced risk management: planning, decision making and monitoring of US wildfire response

Wildfire’s economic, ecological and social impacts are on the rise, fostering the realisation that business-as-usual fire management in the United States is not sustainable. Current response strategies may be inefficient and contributing to unnecessary responder exposure to hazardous conditions, but significant knowledge gaps constrain clear and comprehensive descriptions of how changes in response strategies and tactics may improve outcomes. As such, we convened a special session at an international wildfire conference to synthesise ongoing research focused on obtaining a better understanding of wildfire response decisions and actions. This special issue provides a collection of research that builds on those discussions. Four papers focus on strategic planning and decision making, three papers on use and effectiveness of suppression resources and two papers on allocation and movement of suppression resources. Here we summarise some of the key findings from these papers in the context of risk-informed decision making. This collection illustrates the value of a risk management framework for improving wildfire response safety and effectiveness, for enhancing fire management decision making and for ushering in a new fire management paradigm.

Characterising resource use and potential inefficiencies during large-fire suppression in the western US

Currently, limited research on large-fire suppression effectiveness suggests fire managers may over-allocate resources relative to values to be protected. Coupled with observations that weather may be more important than resource abundance to achieve control objectives, resource use may be driven more by risk aversion than efficiency. To explore this potential, we investigated observed percentage of perimeter contained and self-reported containment values, the exposure index, and patterns of resource use during the containment and control phases of fire response. Fireline production capacity of responding resources typically exceeds final fire perimeter, often by an order of magnitude or more. Additionally, on average, 21% of total incident resource productive capacity was observed on the fire during the control phase, that is, after the fires cease to grow. Our results suggest self-reported percentage containment significantly underestimates actual percentage of perimeter contained throughout an incident, with reported values averaging only 70% contained at actual fire cessation. Combined, these results suggest a fire manager’s risk perception influences resource use and may unnecessarily expose responders to fireline hazards. These results suggest a considerable opportunity to improve large-fire management efficiency by balancing the likelihood and consequences of fire escape against the opportunity cost of resource use.