Wildfires are an inherent part of the landscape in many parts of the world; however, they often impose substantial economic burdens on human populations where they occur, both in terms of impacts and of management costs. As wildfires burn towards human assets, a universal response has been to deploy fire suppression resources (crews, vehicles and aircraft) to extinguish them, and limit their spread or impacts. The determination of the appropriate levels of investment, resource allocation and suppression tactics is a challenge for managers. As suppression expenses account for a substantial proportion of the cost of fires, and escaped fires account for a large portion of impacts, fire suppression models have been developed to better inform decision-makers. We undertake a review of the literature pertaining to the development of operational models that emulate fire suppression as part of decision support systems. We provide a summary of the development of modelling approaches, discuss strengths and limitations and provide perspectives on the direction of future research.

There are multiple pathways for vegetation to change following disturbances. Understanding those post‐disturbance pathways is critical for managing wildfire risk since vegetation is fuel in a wildfire context. Across forest systems, there is considerable debate about disturbance‐related changes to fuels and flammability. This study investigated post‐disturbance fuel trajectories following three disturbance types—high severity wildfire, low severity wildfire, and clear‐fell logging. Fuels were measured in a chrono‐sequence of 141 sites in Mountain Ash (Eucalyptus regnans)‐dominated wet sclerophyll forest in southeastern Australia, a particularly contentious forest system. Wildfires are an important part of the lifecycle of these forests, but too frequent fire can threaten post‐fire regeneration. Large wildfires (in 2009, 1983 and 1939) and ongoing public and scientific debate over clear‐fell logging highlight the need to better understand post‐disturbance trajectories for fuel and flammability in wet sclerophyll forests. We used empirical data to test 10, sometimes contradictory, hypotheses from the scientific literature regarding post‐disturbance pathways for fuel following wildfire and logging. Only five hypotheses were supported with surface fine fuels, fuel hazard, species composition, and vertical structure driving overall differences in post‐disturbance fuel trajectories. The implications for flammability remain uncertain because the independent and interactive effects of many fuel components on overall flammability remain unquantified. Importantly, we found there were always high quantities of fuel, irrespective of disturbance history, which demonstrates that fire occurrence is not fuel‐limited in wet sclerophyll forests. Under conditions of abundant fuel, fuel moisture could become critical to fire occurrence. Therefore, forest management should prioritize efforts to quantify not only the importance of individual fuel components to flammability but also fuel moisture dynamics in wet sclerophyll forests. As the climate (and fuels) becomes drier under climate change, it will be a major challenge to manage fire regimes in these highly valued forests.

Understanding spatial variation in wildland fuel is central to predicting wildfire behaviour as well as current and future fire regimes. Vegetation (plant material) – both live (biomass) and dead (necromass) – constitutes most aspects of wildland fuel (hereafter ‘fuel’). It therefore is likely that factors influencing vegetation structure and composition – climate, soils, disturbance – also will influence fuel structure and associated hazard. Nonetheless, these relationships are poorly understood in temperate environments. In this study, we used an extensive database of fuel hazard assessments to determine the extent to which environmental variables (climatic conditions and soil type) and disturbance (fire) can predict fuel hazard in native vegetation across south‐eastern Australia. Fuel hazard ratings are based on the horizontal and vertical continuity of fine fuels (dead plant material < 6 mm thick, and live plant material < 3 mm thick) that burn in the flaming front of a fire. These scores are used widely by fire managers in Australia. We used environmental and disturbance variables to develop models to predict spatial patterns of hazard for each fuel stratum (surface, near‐surface, elevated and bark) and the height of two fuel strata (near‐surface, elevated). Soil, climate and time since fire were strong predictors of fuel hazard for at least one stratum, and soil predictors were the strongest predictors of fuel hazard across all strata. We used models to predict fuel hazard by stratum at a fixed time since fire in two regions with contrasting environments in south‐eastern Australia to better understand the spatial arrangement of fuel hazard. Fuel hazard varied within and between regions, emphasising the complexity and heterogeneity of fuel patterns that affect fuel hazard from local to landscape extents. The models improve the basis for analysing fuel hazard patterns and therefore increase the capacity to predict fire regimes under future climates.

Wildland fires are a function of properties of the fuels that sustain them. These fuels are themselves a function of vegetation, and share the complexity and dynamics of natural systems. Worldwide, the requirement for solutions to the threat of fire to human values has resulted in the development of systems for predicting fire behaviour. To date, regional differences in vegetation and independent fire model development has resulted a variety of approaches being used to describe, measure and map fuels. As a result, widely different systems have been adopted, resulting in incompatibilities that pose challenges to applying research findings and fire models outside their development domains. As combustion is a fundamental process, the same relationships between fuel and fire behaviour occur universally. Consequently, there is potential for developing novel fuel assessment methods that are more broadly applicable and allow fire research to be leveraged worldwide. Such a movement would require broad cooperation between researchers and would most likely necessitate a focus on universal properties of fuel. However, to truly understand fuel dynamics, the complex biotic nature of fuel would also need to remain a consideration—particularly when looking to understand the effects of altered fire regimes or changing climate.