School of Agriculture, Food and Ecosystem Sciences - Research Publications
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ItemFlammability at field-scales: conducting research in prescribed burns(UNIV COIMBRA, 2018)To better understand the role of plant flammability in driving landscape-scale fire behaviour and fire regimes, field-scale flammability research needs to occur. Yet, experimental fires are costly to implement and research within wildfires is both logistically challenging and potentially dangerous. As an alternative, we propose that operational prescribed burns undertaken for land management purposes should be exploited for flammability research.. In some parts of the world, large areas are burnt annually, providing extensive opportunities for research. In this paper we describe three broad methods that can be used to measure different facets of flammability in prescribed burns. We compare the strengths and potential limitations of each method before finally providing ten principles for conducting effective flammability research in prescribed burns. We conclude that operational prescribed burns are a largely untapped resource that could be used to better understand links between plant flammability and landscape-scale fire behaviour.
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ItemManagement of firebrand potential through the candling of bark fuel(UNIV COIMBRA, 2018)Aerially suspended fuels play an important role in forest fire behaviour. They can act as a ladder to flames, increasing the potential for crownfire, and can ignite and act as firebrands. When large accumulations of these fuels are present, wildfires may spread more rapidly, be more difficult to suppress and be more likely to impact assets such as houses. However, as these fuels are suspended above the ground, their moisture status is predominantly a function of atmospheric humidity. As a result, bark and suspended fuels may become flammable at times when the remainder of the fuel bed is too wet to burn due to high soil moisture levels. This means that these fuels can be reduced by burning when conditions are unfavourable for prescribed burning using the practice candling. Candling is the deliberate ignition of bark and other dead fine ladder fuels under conditions where surface fires are unlikely to spread. We compared the number of days available for prescribed burning and candling for a locality in South Eastern Australia and found that in the period 2012 – 2016, candling could be undertaken for an average 124 days per year, 48 days more than the window available for prescribed burning (76 days). As each accumulation of aerial fuel must be individually lit during candling, the practice is labour intensive and inefficient over large areas relative to prescribed burning, so it is best used for targeted risk reduction such as near control lines or assets. However, it can be used to reduce risk with low chance of escape in locations where prescribed burning is difficult such as the Wildland Urban Interface. The practice is applied operationally in South Eastern Australia, however to date there has been limited research into its effects on wildfire spread and intensity. Given its suitability for strategic use near highly vulnerable assets, we believe further investigation into its utility is warranted.