one 2022




Dead and down woody debris fuel loads in Canadian forests

BY Chelene C. Hanes , Xianli Wang and William J. de Groot 


In Canada, fire behaviour is modelled based on a fuel classification system of 16 fuel types. Average fuel loads are used to represent a wide range of variability within each fuel type, which can lead to inaccurate predictions of fire behaviour. Dead and down woody debris (DWD) is a major component of surface fuels affecting surface fuel consumption, potential crown fire initiation, and resulting crown fuel consumption and overall head fire intensity. This study compiled a national database of DWD fuel loads and analysed it for predictive driving variables. The database included DWD fuel loads for all dominant Canadian forest types at three size classes: fine (<1 cm), medium (1–7 cm) and coarse (>7 cm). Predictive models for DWD fuel load by size classes individually and collectively for various forest types and ecozones were analysed. Bioclimatic regime, age, spatial position, drainage, and structural components including diameter at breast height and stem density were significant variables. This study provides tools to improve our understanding of the spatial distribution of DWD across Canada, which will enhance our ability to represent its contribution within fire behaviour and fire effects models.


‘Any prediction is better than none?’ A study of the perceptions of fire behaviour analysis users in Australia

Timothy Neale, Matteo Vergani , Chloe Begg, Musa Kilinc, Mike Wouters and Sarah Harris


Internationally, fire and land management agencies are increasingly using forms of predictive services to inform wildfire planning and operational response. This trend is particularly pronounced in Australia where, over the past two decades, there has been an alignment between increases in investments in fire behaviour analysis tools, the training and development of fire behaviour analysts (FBANs), and official inquiries recommending the expanded use of these tools and analysts. However, while there is a relative lack of scholarship on the utilisation of predictive services, existing research suggests that institutional investment and availability are poor indicators of use in contexts with established social dynamics of trust and authority. To better understand the utilisation of predictive services in Australia, we undertook a survey of key predictive services users (e.g. incident controllers, planning officers) in order to test several hypotheses developed from existing studies and ethnographic fieldwork. Our results provide directions for further research and indicate that, rather than simply invest in tools and systems, there is a need for fire management agencies to foster personal connection between predictive services practitioners, their tools and their users.


Variability in wildland fuel patches following high-severity fire and post-fire treatments in the northern Sierra Nevada

Ian B. Moore, Brandon M. Collins, Daniel E. Foster, Ryan E. Tompkins, Jens T. Stevens and Scott L. Stephens


Surface fuel loads are highly variable in many wildland settings, which can have many important ecological effects, especially during a wildland fire. This variability is not well described by a single metric (e.g. mean load), so quantifying traits such as variability, continuity and spatial arrangement will help more precisely describe surface fuels. This study measured surface fuel variability in the northern Sierra Nevada of California following a high-severity fire that converted a mixed-conifer forest to shrub-dominant vegetation, both before and after a subsequent shrub removal treatment conducted as site preparation for reforestation. Data were collected on vegetation composition, spatial arrangement and biomass load of the common surface fuel components (1–1000-h woody fuel, litter, duff and shrubs). Mean shrub patch length decreased significantly from 9.25 to 1.0 m and mean dead and down surface fuel load decreased significantly from 131.4 to 73.4 Mg ha−1. Additionally, probability of encountering a continuous high fuel load segment decreased after treatment. This work demonstrates a method of quantifying important spatial characteristics of surface fuel that could be used in the next generation of fire behaviour models and provides metrics that land managers may consider when designing post-fire reforestation treatments.


How to measure the economic health cost of wildfires – A systematic review of the literature for northern America

Ruth Dittrich and Stuart McCallum


There has been an increasing interest in the economic health cost from smoke exposure from wildfires in the past 20 years, particularly in the north-western USA that is reflected in an emergent literature. In this review, we provide an overview and discussion of studies since 2006 on the health impacts of wildfire smoke and of approaches for the estimation of the associated economic cost. We focus on the choice of key variables such as cost estimators for determining the economic impact of mortality and morbidity effects. In addition, we provide an in-depth discussion and guidance on the functioning, advantages and challenges of BenMAP-CE, freely available software of the US Environmental Protection Agency (EPA) that has been used in a growing number of studies to assess cost from wildfire smoke. We highlight what generates differences in outcomes between relevant studies and make suggestions for increasing the comparability between studies. All studies, however, demonstrate highly significant health cost from smoke exposure, in the millions or billions of US dollars, often driven by increases in mortality. The results indicate the need to take health cost into account for a comprehensive analysis of wildfire impacts.