@article {bnh-8192, title = {Risk mitigation from prescribed burning in Kangaroo Island and Mount Lofty Ranges - Black Summer final report}, number = {690}, year = {2021}, month = {08/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

According to the Independent Review into South Australia{\textquoteright}s 2019-20 Bushfire Season, conditions were the worst on record with fires resulting in the loss of three human lives, 196 homes, 660 vehicles, 68,000 livestock, $200m of agricultural production. Around 280,000 ha were burnt by the fires, including total or partial burning of several National Parks.

The Bushfire and Natural Hazards CRC commissioned this project as part of a larger set of Black Summer fires research projects aimed at understanding the record-breaking fire season. This project focuses on answering questions about the effectiveness of prescribed burning, also known as hazard reduction burning, in mitigating risk in two areas affected by fires during the season: The Mount Lofty Ranges east of Adelaide, and Kangaroo Island.

The key questions were:

  1. How does risk respond to treatment in Kangaroo Island, an area with little formal quantification of prescribed burning benefits and costs?
  2. What was the risk in the leadup to the 2019-20 fire season in the Mt Lofty Ranges, and how will risk change in the next five years as a result of the implied fuel reduction from the fires, as well as alternative prescribed burning strategies?

These questions were answered using a well developed methodology combining large scale fire behaviour simulations and Bayesian risk quantification. Similar analyses have been carried out for a range of case study landscapes in southern Australia as part of the Hectares to tailor-made solutions CRC project, with results available online via the end-user tool the Prescribed Burning Atlas, and also the NSW Bushfire Risk Management Research Hub{\textquoteright}s projects for the NSW Bushfire Inquiry.

We found a clear relationship between the rate of prescribed burning and area subsequently burnt by wildfire in the Kangaroo Island case study. This translated into reductions in loss of life and property as well. Risk mitigation was more sensitive to edge treatment than landscape treatment, although both reduced risk. Conversely, increasing treatment (particularly at the edge) resulted in higher areas of the landscape exposed to vegetation being burnt below its minimum tolerable fire interval.

In the Mt Lofty Ranges, we found complex patterns of risk are likely in the aftermath of the 2019-20 fires. In the absence of further wildfire events, risk of area burnt is likely to rise substantially by 2025, regardless of prescribed burning rates, with a similar result for vegetation exposed to too frequent fire. However, risk sto life, property and infrastructure are projected to remain similar to current levels.

Our work contributes to the evidence base for prescribed burning planning in South Australia, with future work potentially examining new management values (e.g. smoke health costs, new biodiversity measures) and exploring empirical relationships between prescribed burning and fire-affected area in 2019-20.

}, keywords = {black summer, kangaroo island, mitigation, Mount Lofty Ranges, Prescribed burning, risk}, issn = {690}, author = {Hamish Clarke and Brett Cirulis and Owen Price and Ross Bradstock and Matthias M. Boer and Anthony Rawlins and Trent Penman} } @article {bnh-7389, title = {From hectares to tailor-made solutions for risk mitigation {\textendash} final project report}, number = {615}, year = {2020}, month = {09/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

We are pleased to present the 2020 Final Report for the Bushfire and Natural Hazards CRC project, {\textquotedblleft}From hectares to tailor-made solutions for risk mitigation: systems to deliver effective prescribed burning across Australian ecosystems{\textquotedblright}.

Prescribed burning is a central feature of contemporary fire management, not just in Australia but in fire-prone countries around the world. Yet we lack a firm quantitative basis for understanding and comparing its effectiveness at mitigating risk across different regions. This project aims to address these gaps and provide critical support to agency decision makers across southern Australia by undertaking a systematic investigation of the drivers of prescribed burning effectiveness across the region. This project will thus support fire managers in transitioning from hectare targets to a set of tailor-made, risk-based approaches.

The project is divided into two phases: fire behaviour accounting and risk accounting. At the heart of the project is predictive modelling of the effect of prescribed burning on subsequent bushfire (wildfire) behaviour. In this project we combine ignition likelihood modelling, fuel type and arrangement from fire management agencies, weather representing all possible local fire weather conditions from Bureau of Meteorology and fire history including wildfire and variable combinations of edge and landscape treatments, applied to agency or model-derived burn blocks. From thousands of simulations, key outputs such as fire size and intensity are used estimate impacts on key management values: house loss, life loss, length of road damaged, length of powerline damaged and area burnt below minimum tolerable fire interval. We use Bayesian decision networks to estimate risk mitigation, including cost, available through different treatments. Local trajectories of cost for given treatment rates and locations can then be tracked and compared between regions, allowing identification of the most cost-effective prescribed burning strategies, either overall or for a given management value.

The key finding of the project is that the effectiveness of prescribed burning at mitigating area burnt by bushfire and other key values varies considerably across landscapes and values. That is, there is no one-size-fits-all solution to prescribed burning. This has major implications for fire managers, suggesting that tailored prescribed burning solutions are possible, based on the unique risk mitigation profile for any given suite of management values in that region. Further details are included in this report and journal articles listed herein.

While the project now draws to a close, its findings live on in the Prescribed Burning Atlas, a dedicated website for fire managers, researchers and anyone else interested in using our project to support their planning, decision making and communication. The Prescribed Burning Atlas will provide a geographically-based summary of risk for decision makers in an accessible, user friendly format. Our project is unique in placing the design and delivery of this utilisation output at its heart. Active involvement of end-users throughout 2020 and beyond will be crucial in ensuring uptake and translation into outcomes for end-users and the communities they serve. From a research perspective, key outstanding questions include quantification of risk mitigation for new values (smoke effects on human health, biodiversity measures, cultural burning) and expansion of the approach to represent the full richness of planned and unplanned landscape fire over time.

}, keywords = {ecosystems, hectares, mitigation, Prescribed burning, risk, systems, tailor-made solutions}, issn = {615}, author = {Hamish Clarke and Brett Cirulis and Trent Penman and Owen Price and Matthias M. Boer and Ross Bradstock} } @article {bnh-5654, title = {Climate change effects on the frequency, seasonality and interannual variability of suitable prescribed burning weather conditions in south-eastern Australia}, journal = {Agricultural and Forest Meteorology}, volume = {271}, year = {2019}, month = {06/2019}, chapter = {148-157}, abstract = {

Despite the importance of prescribed burning in contemporary fire management, there is little understanding of how climate change will influence the weather conditions under which it is deployed. We provide quantitative estimates of potential changes in the number of prescribed burning days in coastal NSW in south-eastern Australia, a fire-prone area dominated by dry sclerophyll forests. Burning days are calculated from an objectively designed regional climate model ensemble using three definitions of suitable weather conditions based on: a literature search (Literature), actual weather observed during recorded prescribed burns (Observed) and operational guidelines (Operational). Contrary to some claims, evidence for a decrease in prescribed burning days under projected future climates is weak. We found a complex pattern of changes, with the potential for substantial and widespread increases in the current burning seasons of autumn (March-May) and spring (August-October). Projected changes were particularly uncertain in northern NSW, spanning substantial increases and decreases during autumn. The magnitude of projected changes in the frequency of burning days was highly sensitive to which definition of suitable weather conditions was used, with a relatively small change for the Operational definition (+0.3 to +1.9 days per year across the study area) and larger ranges for the Observed (+0.2 to +7.9 days) and Literature (+1.7 to +6.2 days) definitions. Interannual variability in the number of burning days is projected to increase slightly under projected climate change. Our study highlights the need for a better understanding of the weather conditions required for safe and effective prescribed burning. Our analysis provides practitioners with quantitative information to assess their exposure to a range of potential changes in the frequency, seasonality and variability of prescribed burning weather conditions.

}, keywords = {Burn window, Climate change, Fire weather, Global warming, Hazard reduction, Prescribed burning, prescribed fire}, doi = {https://doi.org/10.1016/j.agrformet.2019.03.005}, url = {https://www.sciencedirect.com/science/article/pii/S0168192319301091}, author = {Hamish Clarke and Bruce Tran and Matthias M. Boer and Owen Price and Belinda Kenny and Ross Bradstock} } @article {bnh-5697, title = {From hectares to tailor-made solutions for risk mitigation: annual project report 2018-19}, number = {487}, year = {2019}, month = {07/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

We are pleased to present the 2018-2019 Annual Report for the Bushfire and Natural Hazards CRC project, {\textquotedblleft}From hectares to tailor-made solutions for risk mitigation: systems to deliver effective prescribed burning across Australian ecosystems{\textquotedblright}. The project aims to provide critical support to agency decision makers across southern Australia by undertaking a systematic investigation of the drivers of prescribed burning effectiveness across the region. This report describes the background, research approach and key milestones since the previous Annual Report in 2017-2018. The report focuses on the research outputs informing the development of the Prescribed Fire Atlas. The project has now delivered a rich, layered dataset capable of addressing nuanced questions about the quantitative risk reduction available through prescribed burning for multiple management values in varying landscapes. The project is now entering its final phase as we complete climate change and cost-effectiveness analyses and launch the Prescribed Burning Atlas in 2019/20. The Prescribed Burning Atlas will provide geographically based summary of risk for decision makers in an accessible, user friendly format. Our project is unique in placing the design and delivery of this utilisation output at the heart of the project. Active involvement of end users throughout 2020 and beyond will be crucial in ensuring uptake and translation into outcomes for end users and the communities they serve.

}, keywords = {cost-effective, ecosystems, fire management, Prescribed burning}, author = {Hamish Clarke and Owen Price and Matthias M. Boer and Brett Cirulis and Trent Penman and Ross Bradstock} } @article {bnh-6000, title = {Globe-LFMC, a global plant water status database for vegetation ecophysiology and wildfire applications}, journal = {Scientific Data}, volume = {6}, year = {2019}, month = {08/2019}, abstract = {

Globe-LFMC is an extensive global database of live fuel moisture content (LFMC) measured from 1,383 sampling sites in 11 countries: Argentina, Australia, China, France, Italy, Senegal, Spain, South Africa, Tunisia, United Kingdom and the United States of America. The database contains 161,717 individual records based on in situ destructive samples used to measure LFMC, representing the amount of water in plant leaves per unit of dry matter. the primary goal of the database is to calibrate and validate remote sensing algorithms used to predict LFMC. However, this database is also relevant for the calibration and validation of dynamic global vegetation models, eco-physiological models of plant water stress as well as understanding the physiological drivers of spatiotemporal variation in LFMC at local, regional and global scales. Globe-LFMC should be useful for studying LFMC trends in response to environmental change and LFMC influence on wildfire occurrence, wildfire behavior, and overall vegetation health.

}, keywords = {database, Emergency management, land management, Natural disasters, Wildfire spread}, doi = {https://doi.org/10.1038/s41597-019-0164-9}, url = {https://www.nature.com/articles/s41597-019-0164-9.epdf?author_access_token=HISJcfE-VovHPab3al2NwNRgN0jAjWel9jnR3ZoTv0OARKV_7w7xO9p9PGwHd2zKbrs5f-VkYE5AC2lYTydBxaTKy0JaWSgXKUWz0U-fruuzViNrn1JJFl8mARAjGudmQfIcQsd98fM0zv-fk4bXxA\%3D\%3D}, author = {Marta Yebra and Gianluca Scortechini and Abdulbaset Badi and Maria Eugenia Beget and Matthias M. Boer and Ross Bradstock and Emilio Chuvieco and F. Mark Danson and Philip Dennison and Victor Resco de Dios and Carlos M. Di Bella and Greg Forsyth and Philip Frost and Mariano Garcia and Abdelaziz Hamdi and Binbin He and Matt Jolly and Tineke Kraaij and Pillar Martin and Florent Mouillot and Glenn J Newnham and Rachael Nolan and Grazia Pellizzaro and Yi Qi and Xingwen Quan and David Ria{\~n}o and Dar Roberts and Momadou Sow and Susan Ustin} } @conference {bnh-6396, title = {A new decision support tool for prescribed burning risk assessment}, booktitle = {Bushfire and Natural Hazards CRC Research Day AFAC19}, year = {2019}, month = {12/2019}, address = {Melbourne}, abstract = {

In most Australian jurisdictions, the use of prescribed fire is promoted on the basis of its efficacy in mitigation of risk. Despite this, formal attempts to evaluate effects on risk to people, property and environmental values across different jurisdictions are generally lacking. In particular, there is no basis for assessing the generality of attempts to predict risk in response to any particular strategy for use of prescribed fire (e.g. the 5per cent target recommended by the 2009 Victorian Bushfires Royal Commission). General principles therefore need to be developed about how to apply a risk-based approach across widely varying environments, human communities and combinations of key management values.

In this Bushfire and Natural Hazards Cooperative Research Centre project, researchers from the University of Wollongong, Western Sydney University and the University of Melbourne have come together with end users across southern Australia to design a project to systematically investigate how risk to any particular management value will respond to variations in the spatial location and rates of treatment. Project outputs are currently being moulded for utilisation by end users in a dedicated tool, the Prescribed Fire Atlas, which will guide the implementation of {\textquoteleft}tailor-made{\textquoteright} prescribed burning strategies to suit the biophysical, climatic and human context of all bioregions across southern Australia.

}, keywords = {decision support, Fire, perscibed burning, risk management}, url = {https://knowledge.aidr.org.au/resources/australian-journal-of-emergency-management-monograph-series/}, author = {Hamish Clarke and Brett Cirulis and Ross Bradstock and Matthias M. Boer and Trent Penman and Owen Price} } @article {bnh-5615, title = {Quantification of inter-regional differences in risk mitigation from prescribed burning across multiple management values}, journal = {International Journal of Wildland Fire}, year = {2019}, month = {06/2019}, abstract = {

Fire agencies are moving towards planning systems based on risk assessment; however, knowledge of the most effective way to quantify changes in risk to key values by application of prescribed fire is generally lacking. We present a quantification and inter-regional comparison of how risk to management values responds to variations in prescribed burning treatment rate. Fire simulations were run using the PHOENIX RapidFire fire behaviour simulator for two case study landscapes in interface zones in Tasmania and the Australian Capital Territory (ACT), Australia. A Bayesian network approach used these data to explore the influence of treatment and weather on risk from wildfire. Area burnt, length of powerline damaged and length of road damaged responded more strongly to treatment in the ACT than in Tasmania, whereas treatment mitigated house loss and life loss more strongly in Tasmania than the ACT. The effect of prescribed burning treatment rate on area burnt below minimum tolerable fire interval was similar in each case study landscape. Our study shows that the effectiveness of prescribed burning at mitigating area burnt by wildfire and other key values varies considerably across landscapes and values.

}, keywords = {Bushfire, Climate change, trends, Wildfire, wildland fire}, doi = {https://doi.org/10.1071/WF18135}, url = {http://www.publish.csiro.au/WF/WF18135}, author = {Brett Cirulis and Hamish Clarke and Matthias M. Boer and Trent Penman and Owen Price and Ross Bradstock} } @article {bnh-6856, title = {Quantification of inter-regional differences in risk mitigation from prescribed burning across multiple management values}, journal = {International Journal of Wildland Fire}, volume = {29}, year = {2019}, month = {09/2019}, pages = {414-426}, abstract = {

Fire agencies are moving towards planning systems based on risk assessment; however, knowledge of the most effective way to quantify changes in risk to key values by application of prescribed fire is generally lacking. We present a quantification and inter-regional comparison of how risk to management values responds to variations in prescribed burning treatment rate. Fire simulations were run using the PHOENIX RapidFire fire behaviour simulator for two case study landscapes in interface zones in Tasmania and the Australian Capital Territory (ACT), Australia. A Bayesian network approach used these data to explore the influence of treatment and weather on risk from wildfire. Area burnt, length of powerline damaged and length of road damaged responded more strongly to treatment in the ACT than in Tasmania, whereas treatment mitigated house loss and life loss more strongly in Tasmania than the ACT. The effect of prescribed burning treatment rate on area burnt below minimum tolerable fire interval was similar in each case study landscape. Our study shows that the effectiveness of prescribed burning at mitigating area burnt by wildfire and other key values varies considerably across landscapes and values.

}, keywords = {Bushfire, Climate change, trends, Wildfire, wildland fire}, doi = {https://doi.org/10.1071/WF18135}, url = {https://www.publish.csiro.au/WF/WF18135}, author = {Brett Cirulis and Hamish Clarke and Matthias M. Boer and Trent Penman and Owen Price and Ross Bradstock} } @article {bnh-5035, title = {From hectares to tailor-made solutions for risk mitigation: annual project report 2017-18}, year = {2018}, month = {10/2018}, institution = {Bushfire and Natural Hazards CRC}, abstract = {

This report describes the background, research approach and key milestones since the 2016-2017 Annual Report. The report focuses on the analysis of fire spread simulations for two case study landscapes: the ACT and Tasmania. The analysis demonstrates that it is possible to investigate prescribed burning effectiveness at risk mitigation across a range of treatment levels, management values and landscapes, by placing them on a common baseline of risk.

}, issn = {421}, author = {Hamish Clarke and Owen Price and Matthias M. Boer and Brett Cirulis and Trent Penman and Ross Bradstock} } @conference {bnh-4774, title = {A systematic exploration of the potential for bushfire risk mitigation with prescribed burning}, booktitle = {AFAC18}, year = {2018}, month = {09/2018}, publisher = {Bushfire and Natural Hazards CRC}, organization = {Bushfire and Natural Hazards CRC}, address = {Perth}, abstract = {

Fire regimes vary widely across Australian ecosystems as a function of climate, fuel, terrain and ignition variations. Fundamentally such variation will not only shape the way that prescribed burning can reduce risk to human and environmental assets but also the scope for effective treatment. While many agencies are moving toward planning systems based on risk assessment, knowledge of the best way to use prescribed fire to reduce risk to key values is generally lacking. The BNHCRC Project, {\textquotedblleft}From hectares to tailor-made solutions for prescribed burning{\textquotedblright}, combines simulation and empirical approaches to improve our understanding of how risk to any particular management value will respond to variations in the spatial location and rates of treatment. Here, we present the modelling framework and key results for two landscapes, Tasmania and the Australian Capital Territory. We run a large number of simulations using the PHOENIX RapidFire model, investigating the interaction between fuel treatment and location under various weather scenarios. Key outputs for risk assessment include area burnt, house loss, life loss, roads and powerlines damaged, environmental cost and economic cost. Across both case study landscapes, greater levels of prescribed burning tend to result in reduced wildfire impacts on all risks. However, there is considerable variation in the rate of reduction in risk, including the amount of treatment required to achieve key targets. Further, the particular combination of weather factors underpinning given fire weather conditions (e.g. temperature vs wind driven) can substantially impact the overall level of risk, as well as the response to prescribed burning.\ 

}, author = {Brett Cirulis and Hamish Clarke and Ross Bradstock and Matthias M. Boer and Trent Penman and Owen Price} } @article {bnh-4203, title = {From hectares to tailor-made solutions for risk mitigation - systems to deliver effective prescribed burning across Australian ecosystems: annual project report 2016-17}, number = {310}, year = {2017}, month = {09/2017}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

We are pleased to present the 2016-2017 Annual Report for the Bushfire and Natural Hazards CRC project, From hectares to tailor-made solutions for risk mitigation: systems to deliver effective prescribed burning across Australian ecosystems. By undertaking a systematic investigation of the drivers of prescribed burning effectiveness across southern Australia, the project will provide critical support to agency decision makers across the region.

This report describes the project goals, methods and activities since the 2015-2016 Annual Report. The report focuses on initial results from a key project component: fire spread simulations in a range of case study landscapes throughout southern Australia. Results are presented in detail for case studies in East Central Victoria, Adelaide, the ACT and Hobart. This initial suite of simulations provides good evidence that there is substantial variation between case study landscapes in the response of key risks to different rates of prescribed burning. Further simulations in combination with other project methodologies will provide further evidence about this critical issue.

The report also details progress on data acquisition, empirical analyses and stakeholder engagement, which form the other key activities of the project to date. Finally, we are graetful to Naomi Stephens and Felipe Aires, our End User representatives from the NSW Office of Environment and Heritage, for providing an insight into the project{\textquoteright}s progress from a stakeholder perspective.

}, issn = {310}, author = {Hamish Clarke and Owen Price and Matthias M. Boer and Brett Cirulis and Trent Penman and Ross Bradstock} } @article {bnh-2532, title = {Predicting dead fine fuel moisture at regional scales using vapour pressure deficit from MODIS and gridded weather data}, journal = {Remote Sensing of Environment}, volume = {174}, year = {2016}, month = {03/2016}, chapter = {100}, abstract = {

Spatially explicit predictions of fuel moisture content are crucial for quantifying fire danger indices and as inputs to fire behaviour models. Remotely sensed predictions of fuel moisture have typically focused on live fuels; but regional estimates of dead fuel moisture have been less common. Here we develop and test the spatial application of a recently developed dead fuel moisture model, which is based on the exponential decline of fine fuel moisture with increasing vapour pressure deficit (D). We first compare the performance of two existing approaches to predict\ D\ from satellite observations. We then use remotely sensed\ D, as well as\ D\ estimated from gridded daily weather observations, to predict dead fuel moisture. We calibrate and test the model at a woodland site in South East Australia, and then test the model at a range of sites in South East Australia and Southern California that vary in vegetation type, mean annual precipitation (129{\textendash}1404\ mm\ year-\ 1) and leaf area index (0.1{\textendash}5.7). We found that\ D\ modelled from remotely sensed land surface temperature performed slightly better than a model which also included total precipitable water (MAE\ \<\ 1.16\ kPa and 1.62\ kPa respectively).\ Dcalculated with observations from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra satellite was under-predicted in areas with low leaf area index. Both\ D\ from remotely sensed data and gridded weather station data were good predictors of the moisture content of dead suspended fuels at validation sites, with mean absolute errors less than 3.9\% and 6.0\% respectively. The occurrence of data gaps in remotely sensed time series presents an obstacle to this approach, and assimilated or extrapolated meteorological observations may offer better continuity.

}, url = {http://www.sciencedirect.com/science/article/pii/S0034425715302315}, author = {Rachael Nolan and Victor Resco de Dios and Matthias M. Boer and Gabriele Caccamo and Michael L Goulden and Ross Bradstock} } @article {bnh-3432, title = {Biogeographical variation in the potential effectiveness of prescribed fire in south-eastern Australia}, journal = {Journal of Biogeography}, volume = {42}, year = {2015}, month = {09/2015}, pages = {2234-2245}, chapter = {2234}, abstract = {

Aim

Prescribed fire is a common land management for reducing risks from unplanned fires. However, the universality of such effectiveness remains uncertain due to biogeographical variation in fuel types, climatic influences and fire regimes. Here, we explore biogeographical patterns in the effectiveness of prescribed fire by calculating leverage (the reduction in unplanned area burnt resulting from recent previous area burnt) across south-eastern Australia over a 25\ year period.

Location

The 30 bioregions of south-eastern Australia.

Methods

We quantified leverage in each bioregion from fire records from 1975{\textendash}2009, controlling for variation in annual weather. We also identified potential drivers of variation in leverage by relating the bioregional leverage values to measures of fuel type and growth, climate, and weather extremes.

Results

Leverage was inferred in four bioregions while in the other 26 bioregions no leverage was detected or prescribed fire had the opposite effect (fire-follows-fire). Leverage occurred in the forested eastern section of the study area, where rainfall, fuel load and fire activity is high and fire weather is mild. In all bioregions, weather was a stronger predictor than past-fire extent of area burnt in a particular year.

Main conclusions

Our analysis of leverage shows that the effectiveness of prescribed fire varies regionally in predictable ways, which means that fuel management strategies applied in one region are not necessarily applicable in another. In most bioregions prescribed burning is likely to have very little effect on subsequent extent of unplanned fire, and even in regions where leverage occurs, large areas of treatment are required to substantially reduce the area burned by unplanned fire.

}, doi = {10.1111/jbi.12579}, url = {http://onlinelibrary.wiley.com/doi/10.1111/jbi.12579/abstract}, author = {Owen Price and Trent Penman and Ross Bradstock and Matthias M. Boer and Hamish Clarke} } @article {BF-3142, title = {Neighbourhood rules make or break spatial scale invariance in a classic model of contagious disturbance}, journal = {Ecological Complexity}, volume = {8}, year = {2011}, month = {12/2011}, pages = {347 - 356}, abstract = {Scale invariant patterns have been observed in a range of terrestrial and marine ecosystems. These patterns are commonly interpreted as a signature of a self-organising system where global structures emerge from local dynamic interactions between system elements. In effect, an analogy is drawn to the scale invariant output of self-organised model systems, such as the Drossel and Schwabl forest fire model (FFM), and scale invariance in actual systems is then taken to be the product of self-organisation rather than some other process-specific, generative cause. Misinterpretation of the generative mechanism of scale invariance may well have significant consequences for ecosystem management. In actual ecosystems spatial interactions typically vary in form, distance and direction over time, often dependent on exogenous factors such as weather. While simulation models may sometimes represent spatial processes using a variable interaction within a local neighbourhood, what influence this has on model phenomena that are normally attributable to self-organisation has been little studied. We relax a key assumption implicit in the FFM by allowing different sized neighbourhoods over which contagion can occur, rather than maintain a constant sized neighbourhood. We examine how the scaling behaviour of simulated fire sizes changes with a variable neighbourhood size, and show that the invariant scaling typical of the FFM {\textquoteleft}breaks{\textquoteright} with the relaxation of the neighbourhood assumption. Our findings are a strong indication that the generative origins of scale invariance in the FFM (i.e., self-organisation) and in actual fire-prone forest landscapes are essentially different, in contrast to conclusions of previous studies.}, issn = {1476945X}, doi = {10.1016/j.ecocom.2011.07.005}, author = {Matthias M. Boer and Johnston, P and Sadler, Rohan J.} } @article {BF-2411, title = {Dendroecological potential of Callitris preissii for dating historical fires in semi-arid shrublands of southern Western Australia}, journal = {Dendrochronologia}, volume = {28}, year = {2010}, month = {2010}, pages = {37 - 48}, abstract = {Historical fire regimes in the semi-arid shrublands of southern Western Australia are poorly understood, largely owing to a lack of quantitative historical data. We sought to determine the dendroecological potential of fire-sensitive Callitris preissii Miq. trees to date historical fires and extend the length of fire-history data available from remotely sensed imagery. We sampled C. preissii trees from known fire areas in the Lake Johnston region in southern Western Australia. Our objective was to assess the capacity to date historical fires using stand establishment date as a proxy measure of time since fire. We measured stem basal diameter and height and collected stem sections of C. preissii trees and saplings from five areas that were burnt on known dates between 1974 and 2001. We also sampled older trees (>35 years), which were used to create a master chronology to assist with dating of seedlings and saplings. Tree age could not be reliably estimated from stem basal diameter and tree height, with 95\% prediction intervals of more than 17 years. However, we were able to successfully determine tree age and develop a ring-width chronology using standard dendrochronological techniques. The cross-dated chronology showed a relatively high inter-series correlation in ring width (r=0.63) indicating consistency in growth rate among samples and sites, while mean sensitivity (0.39) signified high inter-annual variability in ring width. The age structure of C. preissii stands revealed consistent recruitment within 1 year of fire occurrence and maximum intra-stand variation in tree age of 4 years. Our results confirm that C. preissii has significant dendroecological potential to accurately date past fire events and that this approach will assist in extending fire-history records beyond recent decades for much of southern semi-arid Australia.}, doi = {10.1016/j.dendro.2009.01.002}, author = {O{\textquoteright}Donnell, Alison J. and Cullen, Louise E. and Lachlan W. McCaw and Matthias M. Boer and Grierson, Pauline} } @article {BF-2416, title = {Deriving state-and-transition models from an image series of grassland pattern dynamics}, journal = {Ecological Modelling}, volume = {221}, year = {2010}, month = {02/2010}, pages = {433 - 444}, abstract = {We present how state-and-transition models (STMs) may be derived from image data, providing a graphical means of understanding how ecological dynamics are driven by complex interactions among ecosystem events. A temporal sequence of imagery of fine scale vegetation patterning was acquired from close range photogrammetry (CRP) of 1 m quadrats, in a long term monitoring project of Themeda triandra (Forsskal) grasslands in north western Australia. A principal components scaling of image metrics calculated on the imagery defined the state space of the STM, and thereby characterised the different patterns found in the imagery. Using the state space, we were able to relate key events (i.e. fire and rainfall) to both the image data and aboveground biomass, and identified distinct ecological {\textquoteleft}phases{\textquoteright} and {\textquoteleft}transitions{\textquoteright} of the system. The methodology objectively constructs a STM from imagery and, in principle, may be applied to any temporal sequence of imagery captured in any event-driven system. Our approach, by integrating image data, addresses the labour constraint limiting the extensive use of STMs in managing vegetation change in arid and semiarid rangelands.}, doi = {10.1016/j.ecolmodel.2009.10.027}, author = {Sadler, Rohan J. and Hazelton, Martin and Matthias M. Boer and Grierson, Pauline} } @article {BF-2467, title = {Vegetation and landscape connectivity control wildfire intervals in unmanaged semi-arid shrublands and woodlands in Australia}, journal = {Journal of Biogeography}, volume = {38}, year = {2010}, month = {01/2011}, pages = {112 - 124}, abstract = {Aim The aim of this study was to determine how spatial variation in vegetation type and landscape connectivity influence fire intervals in a semi-arid landscape with low relief and complex mosaics of woodland and shrubland vegetation. Location Our study focused on a 15,500-km2 area of relatively undisturbed and unmanaged land in south-western Australia, referred to as the Lake Johnston region. Methods We modelled fire-interval data from a 67-year (1940{\textendash}2006) digital fire history database using a two-parameter Weibull function, and tested for the effects of vegetation type and landscape connectivity on estimates of the length of fire intervals (Weibull parameter b) and the dependence of fire intervals on fuel age (Weibull parameter c). Results Vegetation type and landscape connectivity significantly influenced fire interval probability distributions. Fire intervals in shrublands (dense low shrub assemblage) were typically shorter (b = 46 years) and more dependent on fuel age (c = 2.33) than most other vegetation types, while fire intervals in open eucalypt woodlands were much longer (b = 405 years) and were less dependent on fuel age (c = 1.36) than in shrub-dominated vegetation types. Areas adjacent to or surrounded by salt lakes burnt less frequently (b = 319 years) and fire intervals were less dependent on fuel age (c = 1.48) compared with more exposed areas (e.g. b < 101 years, c > 1.68). Fire intervals in thickets (dense tall shrub assemblage) were longer (b = 101 years) than would be expected from fuel loads, most likely because they were protected from fire by surrounding fuel-limited woodlands. Main conclusions Fire intervals in south-western Australia are strongly influenced by spatial variation in vegetation (fuel structure) and landscape connectivity. The importance of fuel structure as a control of fire intervals in south-western Australia contrasts with other landscapes, where topographical gradients or climatic influences may override the effects of underlying vegetation. We found that, regardless of low relief, topographical features such as large salt lake systems limited the connectivity and spread of fire among landscape units in an analogous manner to lakes or mountainous features elsewhere.}, issn = {03050270}, doi = {10.1111/j.1365-2699.2010.02381.x}, author = {O{\textquoteright}Donnell, Alison J. and Matthias M. Boer and Lachlan W. McCaw and Grierson, Pauline} } @article {BF-2412, title = {Impacts of increased fire frequency and aridity on eucalypt forest structure, biomass and composition in southwest Australia}, journal = {Forest Ecology and Management}, volume = {258}, year = {2009}, month = {10/2009}, pages = {2136 - 2142}, abstract = {Water stress and fire disturbance can directly impact stand structure, biomass and composition by causing mortality and influencing competitive interactions among trees. However, open eucalypt forests of southwest Australia are highly resilient to fire and drought and may respond differently to increased fire frequency and aridity than forests dominated by non-eucalypt species. We measured the variation in stem density, basal area, stand biomass, sapwood area, leaf area and litterfall across 16 mixed jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) forest stands along an aridity gradient in southwest Australia that had variable fire histories. Fire frequency was defined as the total number of fires over a not, vert, similar30-year period and aridity as the ratio of potential evapotranspiration to annual precipitation. Total stand biomass and sapwood area were predicted from diameter at breast height of individual jarrah and marri trees using allometric equations. Leaf area was estimated using digital cover photography. More arid and frequently burnt stands had higher stem density, especially of smaller trees, which were mainly jarrah. Overall, both standing biomass and leaf area decreased at more arid sites, while sapwood area was largely unaffected by aridity, suggesting that these stands respond to increased water limitation by decreasing their leaf area relative to their sapwood area. Biomass of marri was reduced at more arid and, to a lesser extent, at more frequently burnt stands. However, total stand biomass (jarrah and marri) and leaf area index did not vary with fire frequency, suggesting that less marri biomass (due to slower growth rates, higher mortality or less recruitment) was compensated by an increase in the density of jarrah trees (regeneration). We conclude that increased fire and drought shift tree species composition towards more fire-resistant species and result in denser stands of smaller trees. In contrast, total stand biomass declines with increasing aridity, but has no association with fire frequency.}, doi = {10.1016/j.foreco.2009.08.013}, author = {Pekin, BK and Matthias M. Boer and Macfarlane, C and Grierson, Pauline} } @article {BF-2396, title = {Long-term impacts of prescribed burning on regional extent and incidence of wildfires{\textemdash}Evidence from 50 years of active fire management in SW Australian forests}, journal = {Forest Ecology and Management}, volume = {259}, year = {2009}, month = {12/2009}, pages = {132 - 142}, abstract = {Prescribed burning is advocated for the sustainable management of fire-prone ecosystems for its capacity to reduce fuel loads and mitigate large high-intensity wildfires. However, there is a lack of comprehensive field evidence on which to base predictions of the benefits of prescribed burning for meeting either wildfire hazard reduction or conservation goals. Australian eucalypt forests are among the very few forest types in the world where prescribed burning has been practised long enough and at a large enough spatial scale to quantify its effect on the incidence and extent of unplanned fires. Nevertheless even for Australian forests evidence of the effectiveness of prescribed burning remains fragmented and largely unpublished in the scientific literature. We analysed a 52-year fire history from a eucalypt forest region in south-western Australia to quantify the impact of prescribed burning on the incidence, extent and size distribution of wildfires. Quantile regression identified the longevity of the influence of prescribed fire treatments on wildfire incidence and extent. Anomalies in the frequency-size distribution of unplanned fires were identified through a relative risk mapping using kernel density estimates. Changes in the spatial distribution of fuel age were quantified using patch metrics, while generalized additive models were applied to estimate effects of fuel age patterns on the incidence and extent of unplanned fire. Prescribed burning has pronouncedly changed the spatial distribution of fuel age in the study area and has significantly reduced the incidence and extent of unplanned fires. This effect on both the incidence and extent of unplanned fires was minimal for time lags greater than 6 years between fuel treatment and response. When averaged over 6-year periods, the annual extent of prescribed burning explained 24\% and 71\% of the variation in the mean annual number and extent of unplanned fires, respectively. The incidence of large unplanned fires was significantly less than the long-term average for the region when the annual extent of prescribed fire was at a maximum and significantly more when the annual extent of prescribed fire was at a minimum. Since the 1960s, the length of time sites remain unburned by wildfire has approximately doubled to not, vert, similar9 years. We found that each unit area reduction in unplanned fire required about four units of prescription fire. These findings concur with the observations of experienced field practitioners who identify the 6-year mark as effective at reducing wildfire hazard. Our findings provide strong empirical evidence of the effectiveness of prescribed burning for mitigating wildfire hazard in SW Australian forests. Ongoing research and development is needed to implement managed fire regimes that integrate wildfire mitigation with conservation of biodiversity and other environmental values.}, doi = {10.1016/j.foreco.2009.10.005}, author = {Matthias M. Boer and Sadler, Rohan J. and Wittkuhn, Roy and Lachlan W. McCaw and Grierson, Pauline} } @article {BF-2376, title = {Mapping burned areas and burn severity patterns in SW Australian eucalypt forest using remotely-sensed changes in leaf area index}, journal = {Remote Sensing of Environment}, volume = {112}, year = {2008}, month = {12/2008}, pages = {4358 - 4369}, abstract = {Remote sensing is the most practical method available to managers of fire-prone forests for quantifying and mapping fire impacts. Differenced Normalised Burn Ratio (ΔNBR) is among the most widely used spectral indices for the mapping of burn severity but is difficult to interpret in terms of fire-related changes in key biophysical attributes and processes. We propose to quantify burn severity as a change in the leaf area index (ΔLAI) of a stand. LAI is a key biophysical attribute of forests, and is central to understanding their water and carbon cycles. Previous studies have suggested that changes in canopy LAI may be a major contributor to ΔNBR and to the composite burn index (CBI) that is frequently used in combination with the NBR to assess burn severity on the ground. We applied remotely-sensed ΔLAI to map burn severity in jarrah (Eucalyptus marginata) forest in south-western Australia burnt during the January 2005 Perth Hills wildfires. Ground-based digital photography was used to measure LAI in typical stands representing the full range of canopy densities present in the study area as well as variation in the time since the last fire. Regression models for the prediction of LAI were developed using NBR, the Normalised Difference Vegetation Index (NDVI) or the Simple Ratio (SR) as the independent variable. All three LAI models had equally high coefficients of determination (R2: 0.87) and small root mean squared errors (RMSE: 0.27{\textendash}0.28). ΔLAI was calculated as the difference between pre- and post-fire LAI, predicted using imagery from January 2004 and February 2005, respectively. The area affected by the January 2005 fire and the burn severity patterns within that area were mapped using ΔLAI and ΔNBR. Landscape patterns of burn severity obtained from differencing pre- and post-fire LAI were similar to those mapped by ΔNBR. We conclude that fire-affected areas and burn severity patterns in the northern jarrah forest can be objectively mapped using remotely-sensed changes in LAI, while offering the important advantage over NBR of being readily interpretable in the wider context of ecological forest management.}, doi = {10.1016/j.rse.2008.08.005}, author = {Matthias M. Boer and Macfarlane, C and Jaymie Norris and Sadler, Rohan J. and Wallace, J and Grierson, Pauline} } @article {BF-2377, title = {Spatial scale invariance of southern Australian forest fires mirrors the scaling behaviour of fire-driving weather events}, journal = {Landscape Ecology}, year = {2008}, abstract = {Power law frequency-size distributions of forest fires have been observed in a range of environments. The scaling behaviour of fires, and more generally of landscape patterns related to recurring disturbance and recovery, have previously been explained in the frameworks of self-organized criticality (SOC) and highly optimized tolerance (HOT). In these frameworks the scaling behaviour of the fires is the global structure that either emerges spontaneously from locally operating processes (SOC) or is the product of a tuning process aimed at optimizing the trade-offs between system yield and tolerance to risks (HOT). Here, we argue that the dominant role of self-organized or optimised fuel patterns in constraining unplanned-fire sizes, implicit in the SOC and HOT frameworks, fails to recognise the strong exogenous controls of fire spread (i.e. by weather, terrain, and suppression) observed in many fire-prone landscapes. Using data from southern Australia we demonstrate that forest fire areas and the magnitudes of corresponding weather events have distributions with closely matching scaling exponents. We conclude that the spatial scale invariance of forest fires may also be a mapping of the meteorological forcing pattern. }, doi = {10.1007/s10980-008-9260-5}, author = {Matthias M. Boer and Sadler, Rohan J. and Ross Bradstock and Gill, A. Malcolm and Grierson, Pauline} } @proceedings {BF-2992, title = {Self-organization of Fire-prone Landscape Systems: Concepts, models and field evidence}, year = {2005}, month = {August 2005}, publisher = {Ecological Society of America}, address = {USA, United States of America }, keywords = {Australia, Self-organization, spatial patterns, wildland fire}, url = {http://abstracts.co.allenpress.com/pweb/esa2005/document/48216}, author = {Matthias M. Boer and Grierson, Pauline} }