@article {bnh-8328, title = {Post-fire impact assessment of Tasmanian sphagnum bogs}, number = {724}, year = {2022}, month = {03/2022}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

In the summer of 2015-2016 several large dry lightning storms ignited wildfires that burned across Western Tasmanian landscapes desiccated by the combination of severe spring drought and above average summer temperatures. Approximately 20 000 ha of the Tasmanian Wilderness World Heritage Area burnt including Sphagnum moss communities, or {\textquoteleft}sphagnum bogs{\textquoteright}, and other significant areas of high conservation value Gondwanan refugia. The scale of the fires prompted the Tasmanian government to fund research in techniques to rehabilitate fire-impacted Gondwanan refugia, including sphagnum bogs, in the Lake Mackenzie area of the Northern Central Plateau. A key step in sphagnum bog restoration is the development of rapid, broad-scale, cost-effective and low impact survey techniques to identify sites in need of rehabilitation. We trialled unmanned aerial systems (UAS) with visible spectrum sensor technology to map fire extent and severity.\  Three sphagnum bogs were used to develop an ENVI classification workflow based on a training data set of burn severity categories and other ecological surface cover measurements to map burn severity.\  These maps were validated using ocular assessments of ground cover and burn severity in pre-existing permanently marked quadrats. We found poor to moderate agreement between the UAS and field fire severity with considerable variation amongst the sampled bogs. Total burnt area sphagnum bog maps were then produced by combining burnt severity categories for five bogs, including the three used for fire severity mapping, The congruence between Sphagnum burn extent maps with field data collected by differential Global Positioning System was found to range from substantial to poor according to Cohen{\textquoteright}s Kappa index. Multivariate analysis of the quadrat ground cover assessments showed that high grass cover was most strongly associated with poor field validation agreement (low Kappa scores), whereas acceptable field validation agreement (high Kappa scores), were associated with high cover of Sphagnum. A major constraint of this study was the two-year time gap between the fire and remote sensing mapping and field survey. Higher accuracy fire severity mapping and area burned mapping would be possible if imagery was acquired immediately after a fire event. In light of our findings, we provide recommendations for future UAS surveys of fire impacted sphagnum bogs, the most critical of which is acquiring remote sensing and field data in the same growing season as the fire.

}, keywords = {bogs, impact assessment, post-fire, sphagnum, Tasmanian}, issn = {724}, author = {Morgan Harding and Darren Turner and Grant Williamson and Scott Nichols and David Bowman} } @article {bnh-7977, title = {Bioclimatic drivers of fire severity across the Australian geographical range of giant Eucalyptus forests}, journal = {Journal of Ecology}, year = {2021}, month = {04/2021}, abstract = {

The relationships between productivity, fire frequency and fire severity shape the distribution of plant communities globally. Dry forests are expected to burn frequently and wet forests to burn infrequently. However, the effect of productivity on intensity and severity of wildfire is less consistent and poorly understood. One productive ecosystem where this is especially true is the Australian tall wet Eucalyptus-dominated forest (TWEF), which spans wet areas across the continent. This study aims to characterise how climate shapes the likelihood of low- and high-severity wildfire across Australian TWEF.

We performed a continental-scale analysis of fuels in 48 permanent plots in early-mature stage TWEF across four climate regions in Australia. We estimated fuel loads and measured understorey microclimate. We then obtained historical fire-weather observations from nearby meteorological stations and used fuel moisture and fire behaviour equations to predict the historical frequency with which TWEF could burn and what fire severities were expected. We investigated how this varies across the different TWEF climate regions. Lastly, we validated our approach by remeasuring eight plots that burned unexpectedly post-measurement.

We found that surface fuels in cooler, moister regions were available to burn 1{\textendash}16\ days per year historically, with only low-severity, surface fire possible most of these days: high-severity fire was only possible under rare, extreme fire-weather conditions. However, in warmer, drier regions, fuels were available to burn 23{\textendash}35\ days annually, and high-severity fire was more likely than low-severity fire. Validation showed that we slightly overestimated flame heights, inflating high-severity risk estimates. If we used elevated fuel loads to predict flame heights, however, high-severity fire was more likely than low-severity fire everywhere. Lastly, the likelihood of high-severity fire increased with increasing temperature and worsening fire weather.

Synthesis. Fire activity in early-mature TWEF is limited by climatic constraints on fire weather and availability to burn, with high-severity fire more likely in warmer, drier regions than in cooler, wetter ones. This indicates a particularly worrisome vulnerability to climate change, given TWEF{\textquoteright}s diminished ability to recover from disturbance in a warmer world. The occurrence of both low- and high-severity fire means the fire regimes of TWEF are best described as mixed severity.

}, keywords = {biogeography, Climate change, ecological disturbance, fire ecology, fire severity, macroecology, mixed-severity fires, tall wet Eucalyptus forests}, doi = {https://doi.org/10.1111/1365-2745.13663}, url = {https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13663}, author = {Furlaud, James M. and Lynda Prior and Grant Williamson and David Bowman} } @article {bnh-7954, title = {Demographic effects of severe fire in montane shrublands on Tasmania{\textquoteright}s Central Plateau}, number = {658}, year = {2021}, month = {04/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

Australian montane sclerophyll shrubland vegetation is considered to be resilient to infrequent severe fire but this may not be the case in Tasmanian shrublands. Our research reports on the regeneration response of a Tasmanian non-coniferous woody montane shrubland following a severe fire. The 2019 Great Pine Tier fire in the Central Plateau Conservation Area was a severe crown fire that killed all above ground vegetation in the shrubland. Our field survey revealed that less than 1\% of the burnt plants were not top-killed by the fire, and only 5\% of the burnt plants were observed to be resprouting one year following the fire. Such a low resprouting rate means the resilience of the shrubland depends on seedling regeneration from aerial and soil seedbanks or colonisation from plants outside the fire ground. The low number of resprouters within the shrubland suggest that it may not be as resilient to fire as mainland Australian montane shrubland. As a consequence, our research highlights the fragility of the shrubland under a warming climate and potential increase in fire frequency.

}, keywords = {demographic, effects, Fire, montane, severe, shrublands, Tasmania}, issn = {658}, author = {Judy Foulkes and Steven Leonard and David Bowman} } @article {bnh-8081, title = {Understanding post-fire fuel dynamics using burnt permanent forest plots}, number = {674}, year = {2021}, month = {06/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

The main goal of this study is to obtain empirical measurements of fuel load, structure and hazard within the first two years after a fire to complement the measurements of fuel loads taken directly before the fires.\  This will not only allow us to precisely quantify the fuel loads consumed by a range of fires, but it will also give us a baseline measurement of fuel loads.\  We can use this baseline to anchor measurements of fuel accumulation in wet eucalypt forests that are part of related TERN and BNHCRC studies attempting to measure both the effects of climate and stand age on fuel accumulation in wet forests.

Current state of knowledge

The flammability of tall wet eucalypt forests is poorly understood. A globally unique forest type, these forests consist of a highly-flammable Eucalyptus overstorey and a moist, non-flammable understorey consisting of rainforest and broadleadf trees and shrubs. As a result, these forests are rarely available to burn, and almost no data exists on flammability and fire behaviour. While current fire behaviour models assume that fuel load and hence flammability increase asymptotically as a function of time since previous fire,\ there is much debate over whether this is the true trajectory of flammability in these forests. Understanding how fire severity is influenced by fuels and time since fire is a critical question in these forests.

As the rate of spread and intensity of a fire is a function of fuels, fire weather and topography, and as only the latter can be physically manipulated, the effect of fuel load and structure on fire behaviour, and the subsequent reduction in fuels, is extremely important to understand.\  Planned burning, the intentional use of low-severity fire, is the most commonly employed fuel reduction technique in Australia.\  The underlying concept is that burning off fuel loads across a landscape leads to an increased encounter rate with low fuel load areas.7 While reducing fuel ages has been shown to reduce both the extent and incidence of unplanned fires, the effect of low severity fires on actual fuel loads has not been explicitly quantified, especially in wet forests where planned burning is less commonly practiced than in dry forest.\  Further, low-severity fires have historically been overlooked in wet forests, as high-severity fires are though to be the important disturbance type due to the serotinous nature of many eucalypts. But recent research indicates that low-severity fires could play a more important role that previously realised.

Related projects

This study is building a large dataset of pre- and post-fire permanent plot measurements to complement existing studies on the fire regime of wet eucalypt forests. As mentioned above it utilised infrastructure set up as part of the TERN forests Ausplots network, and the Warra Chronosequence plots. Such a dataset will allow for analyses such as\  the validation of fire behaviour models, analysis of the resilience wet forests to wildfire, and help understand how fire severity affects subsequent fire hazard. Data from this study has already added a valuable validation section to a study providing the first-ever explicit description of the fire regime of mature wet Eucalyptus forests across Australia.26\ 

This project has also contributed a valuable high-resolution field-based validation for the BNHCRC project Using pre and post fire LiDAR to assess the severity of the 2019 Tasmanian Bushfires. This project will create, among other things, a high-resolution fire-severity map of the Riveaux Road Fire. With these data, we will be able to perform geospatial analyses to untangle the drivers of fire severity during this bushfire. Importantly the area burned in the fire includes the WARRA silvicultural experiment, in which a number of silvicultural treatments were trialled in a small area. This will allow an investigation into the effects of different silvicultural practices on flammability and fire severity in tall wet Eucalyptus forests.

Research questions

This study plans to focus on three major research questions:

}, keywords = {burnt, dynamics, forest, fuel, permanent, plots, post-fire}, issn = {674}, author = {Furlaud, James M. and David Bowman} } @article {bnh-8165, title = {Using pre- and post-fire LiDAR to assess the severity of the 2019 Tasmanian bushfires}, number = {698}, year = {2021}, month = {08/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {MELBOURNE}, abstract = {

In January 2019, over 64,000 ha of bushland burned in the Riveaux Road fire in Tasmania{\textquoteright}s southern forests. Most of area burned occurred in tall wet eucalypt forest. These forests are considered to be highly flammable in dry conditions, but fires are infrequent due to the generally cool, wet climate in which they grow. As a result, limited data exists on the behaviour and effects of wildfire in these forests. Prior to these fires, extensive areas of these southern forests have been studied in-depth. In 2014, a large area of the forests that burned were mapped with aerial LiDAR, a remote-sensing technology that can characterise three-dimensional forest structure. Further, in 2016, detailed field-based measurements of fuel load, structure, and hazard were taken at 12 permanent plots which subsequently burned in 2019. Hence, the 2019 fires in Tasmania represent a globally-rare opportunity to characterise the severity of a large wildfire using pre-fire and post-fire data. In October 2019, the Department of Primary Industries, Parks, Water and Environment (DPIPWE) in Tasmania, along with five other BNHCRC end-users and the University of Tasmania, launched a project to use remote-sensing and field-based data to create a detailed case study of the 2019 Riveaux Rd. Fire, and to untangle the drivers of fire severity in tall wet eucalypt forests.\  To do this we (i) remeasured plots to assess tree mortality and changes in fuel loads post fire; (ii) acquired LiDAR data from a transect across a burned buttongrass-forest boundary on the Weld River enabling comparison with pre-fire LiDAR data; (iii) established baseline postfire LiDAR buttongrass-forest boundary transect on the Huon River at Blakes Opening.\  Here we describe the data sets and report some preliminary analyses.

}, keywords = {Bushfire, fire severity, Lidar, post-fire, pre-fire, Tasmania}, issn = {698}, author = {Furlaud, James M. and Arko Lucieer and Scott Foyster and Anna Matala and David Bowman} } @article {bnh-7475, title = {Exploring the key drivers of forest flammability in wet eucalypt forests using expert-derived conceptual models}, journal = {Landscape Ecology}, volume = {35}, year = {2020}, month = {06/2020}, pages = {1775{\textendash}1798}, abstract = {

Context

Fire behaviour research has largely focused on dry ecosystems that burn frequently, with far less attention on wetter forests. Yet, the impacts of fire in wet forests can be high and therefore understanding the drivers of fire in these\ systems\ is vital.

Objectives

We sought to identify and rank by importance the factors plausibly driving flammability in wet eucalypt forests, and describe relationships between them. In doing so, we formulated a set of research priorities.

Methods

Conceptual models of forest flammability in wet eucalypt forests were elicited from 21 fire experts using a combination of elicitation techniques. Forest flammability was defined using fire occurrence and fireline intensity as measures of ignitability and heat release rate, respectively.

Results

There were shared and divergent opinions about the drivers of flammability in wet eucalypt forests. Widely agreed factors were drought, dead fine fuel moisture content, weather and topography. These factors all influence the availability of biomass to burn, albeit their effects and interactions on various dimensions of flammability are poorly understood. Differences between the models related to lesser understood factors (e.g. live and coarse fuel moisture, plant traits, heatwaves) and the links between factors.

Conclusions

By documenting alternative conceptual models, we made shared and divergent opinions explicit about flammability in wet forests. We identified four priority research areas: (1) quantifying drought and fuel moisture thresholds for fire occurrence and intensity, (2) modelling microclimate in dense vegetation and rugged terrain, (3) determining the attributes of live vegetation that influence forest flammability, (4) evaluating fire management strategies.

}, keywords = {Cognitive mapping, Conceptual models, Expert elicitation, Fire behaviour, fire intensity, flammability, Structured decision-making, Structured expert judgement, Wet forest, Wildfire}, doi = {https://doi.org/10.1007/s10980-020-01055-z}, url = {https://link.springer.com/article/10.1007/s10980-020-01055-z}, author = {Jane Cawson and Victoria Hemming and Ackland, A and Wendy R. Anderson and David Bowman and Ross Bradstock and Brown, T and Jamie Burton and Geoffrey J. Cary and Thomas Duff and Alex Filkov and Furlaud, James M. and Tim Gazzard and Kilinc, Musa and Petter Nyman and Ross Peacock and Mike Ryan and Jason J. Sharples and Gary J. Sheridan and Tolhurst, K.G. and Tim Wells and Phil Zylstra and Trent Penman} } @article {bnh-6929, title = {Understanding post-fire fuel dynamics using burnt permanent forest plots}, number = {569}, year = {2020}, month = {05/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The main goal of this study is to obtain empirical measurements of fuel load, structure and hazard within the first year after a fire to complement the measurements of fuel loads taken directly before the fires. This will not only allow us to precisely quantify the fuels consumed by these relatively low-severity fires, but it will also give us a baseline measurement of fuel loads. We can use this baseline to anchor measurements of fire severity and fuel accumulation in wet eucalypt forests related to other BNHCRC studies attempting to measure both fuel accumulation and the drivers of fire severity in wet forests.

The flammability of tall wet eucalypt forests is poorly understood. A globally unique forest type, these forests consist of a highly-flammable Eucalyptus overstorey and a moist, non-flammable understorey consisting of rainforest and broadleadf trees and shrubs.[i], As a result, these forests are rarely available to burn, and almost no data exists on flammability and fire behaviour. While current fire behaviour models assume that fuel load and hence flammability increase asymptotically as a function of time since previous fire, there is much debate over whether this is the true trajectory of flammability in these forests. Understanding how fire severity is influenced by fuels and time since fire is a critical question in these forests.

As the rate of spread and intensity of a fire is a function of fuels, fire weather and topography, and as only the latter can be physically manipulated, the effect of fire on fuel loads is extremely important to understand.\  Low-severity fires are known to reduce surface fine fuels loads across a landscape in certain forest types, so intentionally lighting low-severity fires (i.e. planned burns), will increase the encounter rate of wildfires with low fuel load areas.7 However the effect of low-severity fires in wetter forests is mostly unstudied. While reducing fuel ages has been shown to reduce both the extent and incidence of unplanned fires, the effect of low severity fires on actual fuel loads has not been explicitly quantified.\  While the period of effectiveness of a planned burn has been generally reported to be 5-6 years,8,\ these studies have looked at the empirical probability or size of unplanned fires as a function of fuel age, no studies that we could find in Australia measured fuel loads directly after a low-severity fire.

}, keywords = {eucalypt forest, fuel dynamics, permanent forest plots, post-fire}, issn = {569}, author = {Furlaud, James M. and David Bowman} } @article {bnh-7465, title = {Using pre- and post-fire LiDAR to assess the severity of the 2019 Tasmanian bushfires: field survey methods}, number = {620}, year = {2020}, month = {10/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

In January 2019, over 64,000 ha of bushland burned in the Riveaux Road fire in Tasmania{\textquoteright}s southern forests. Most of this burning occurred in tall wet eucalypt forest. These forests are considered to be highly flammable in dry conditions, but fires are infrequent due to the generally cool, wet climate in which they grow. As a result, limited data exists on the behaviour and effects of wildfire in these forests. Prior to these fires, extensive areas of these southern forests have been studied in-depth. In 2014, a large area of the forests that burned were mapped with aerial LiDAR, a remote-sensing technology that can characterise three-dimensional forest structure. Further, in 2016, detailed field-based measurements of fuel load, structure, and hazard were taken at 12 permanent plot which subsequently burned in 2019. Hence, the 2019 fires in Tasmania represent a globally-rare opportunity to characterise the severity of a large wildfire using pre-fire and post-fire data. In October 2019, the Department of Primary Industries, Parks, Water and Environment (DPIPWE) in Tasmania, along with five other BNHCRC end-users and the University of Tasmania, launched a project to do just this, using remote-sensing and field-based data to create a detailed case study of the 2019 Riveaux Rd. Fire, and to untangle the drivers of fire severity in tall wet eucalypt forests.

Here, we present the Methodology this study. We took measurements at the 12 permanent plots that burned, dividing our measurements based on 2 levels of detail, based on the level of detail of the pre-fire measurements. In four plots we took {\textquoteleft}Level 1{\textquoteright} measurements, undertaking an overstorey census over 1 ha, assessing overstorey mortality. In 12 plots, we took {\textquoteleft}Level 2{\textquoteright} measurements, which involved characterising understorey phiognomy, structure fuel load, and fire hazard along 3-4 transects at each plot. For Level 1\&2 measurements we also took numerous fire severity measurements, such as char height and burnt tip diameter.\  We also developed a {\textquoteleft}Level 3{\textquoteright} methodology of mostly qualitative fire severity indices that could be quickly conducted at many sample points across the landscape. quantifying fuel load, structure, mortality, hazard, and fire severity indices such as char height and burnt tip diameter. We also outline the next steps to be taken for this project.

}, keywords = {2019 Tasmania fires, field survey method, fire severity, Lidar}, issn = {620}, author = {Furlaud, James M. and Scott Foyster and David Bowman} } @article {bnh-7344, title = {Variation in Eucalyptus delegatensis post-fire recovery strategies: The Tasmanian subspecies is a resprouter whereas the mainland Australian subspecies is an obligate seeder}, journal = {Forest Ecology and Management}, volume = {473}, year = {2020}, month = {10/2020}, abstract = {

Eucalyptus delegatensis\ is native to the Australian Alps (subsp.\ delegatensis) and montane Tasmania (subsp.\ tasmaniensis).\ Post-fire regeneration mechanisms of the obligate-seeder subspecies on the Australian mainland are well-known, but less is known about the resprouter Tasmanian subspecies. In January 2016, large tracts of\ Eucalyptus delegatensis\ forests in central Tasmania, logged at different intensities, were burnt by low- and high-severity fire. We used statistical modelling to understand how tree survival, vegetative regeneration and seedling recruitment differed according to understorey type, fire severity, logging intensity and tree size (DBH). Fire severity, defined as unburnt, low-severity (fire scarring on the stem and/or lower canopy burnt) and high-severity (full canopy burnt), affected tree survival: 84\% of trees were alive in unburnt transects, compared with 43\% in low-severity transects and 36\% in high-severity transects. Epicormic resprouting was the dominant mode of vegetative recovery, with\ \<\ 1\% of total trees recovering solely by basal resprouting. Fire severity significantly affected epicormic resprouting, with 70\% of live stems resprouting post-fire in low-severity transects and 99\% in high-severity transects, compared with 4\% in unburnt transects. Tree survival was strongly influenced by tree size: in high-severity transects, 24\% of trees with DBH\ \<\ 20\ cm were alive, compared with 88\% of trees with DBH\ >=\ 20\ cm. These differences in survival were primarily because large trees were more likely to resprout epicormically, with epicormic shoots present on 24\% of live trees with DBH\ \<\ 20\ cm, compared with 79\% of live trees with DBH\ >=\ 80\ cm. The strong effect of tree size renders clear-felled forests especially vulnerable to fire during the several decades when all the regenerating trees are small (DBH\ \<\ 20\ cm). Seedling recruitment was uncommon, independent of understorey type and logging intensity, but with higher occurrence on high-severity (54\%) than low-severity (19\%) or unburnt (15\%) transects. When present, seedling densities were typically low: median\ =\ 400 and maximum\ =\ 4{\textperiodcentered}104\ seedlings ha-1. This study highlights that mature forests of\ Eucalyptus delegatensis\ in Tasmania are more resilient (able to return to pre-disturbance conditions) to single high-severity fires than their mainland counterparts, because they can recover more quickly through epicormic resprouting. However, clear-felling reduces this resilience for several decades because it decreases median tree size and, hence, leads to higher post-fire mortality. It is difficult to predict how the Tasmanian subspecies will respond to an increased frequency of high-severity fires associated with a projected warmer and drier climate.

}, keywords = {Clear-felling, Epicormic resprouting, Eucalyptus delegatensis, fire severity, Seedlings, Tasmania, Tree size, Tree survival, Understorey type}, doi = {https://doi.org/10.1016/j.foreco.2020.118292}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0378112720310616}, author = {Dario Rodriguez-Cubillo and Lynda Prior and David Bowman} } @article {bnh-6392, title = {Evolution of an extreme Pyrocumulonimbus-driven wildfire event in Tasmania, Australia}, journal = {Natural Hazards and Earth System Sciences}, year = {2019}, month = {12/2019}, abstract = {

Extreme fires have substantial adverse effects on society and natural ecosystems. Such events can be associated with intense coupling of fire behaviour with the atmosphere, resulting in extreme fire characteristics such as pyrocumulonimbuscloud (pyroCb) development. Concern that anthropogenic climate change is increasing the occurrence of pyroCbs globally is driving more focused research into these meteorological phenomena. Using 6-minute scans from a nearby weather radar, we describe the development of a pyroCb during the afternoon of 4 January 2013 above the Forcett-Dunalley fire in south-eastern Tasmania. We relate storm development to: (1) near-surface weather using the McArthur Forest Fire Danger Index (FFDI), and the C-Haines Index, a measure of the vertical atmospheric stability and dryness both derived from gridded weather reanalysis for Tasmania (BARRA-TA), and (2) a chronosequence of fire severity derived from remote sensing. We show that the pyroCb rapidly developed over a 24-minute period in the afternoon of 4 January, with the cloud top reaching a height of 15 km. The pyroCb was associated with a highly unstable atmosphere (C-Haines 10-11) and Severe-marginally Extreme (FFDI 60-75) near-surface fire weather, and formed over an area of forest that was severely burned (total crown defoliation). We use spatial patterns of elevated fire weather in Tasmania, and fire weather during major runs of large wildfires in Tasmania for the period 2007-2016 to geographically and historically contextualise this pyroCb event. Although the Forcett-Dunalley fire is the only known record of a pyroCb in Tasmania, our results show that eastern and south-eastern Tasmania are prone to the conjunction of high FFDI and C-Haines values that have been associated with pyroCb development. Our findings have implications for fire weather forecasting and wildfire management, and highlight the vulnerability of southeast Tasmania to extreme fire events.

}, keywords = {C-Haines, extreme fire, fire severity, Fire weather, McArthur Forest Fire Danger Index, pyrocumulonimbus, smoke plume injection, Tasmania, wildland fire}, doi = {https://doi.org/10.5194/nhess-2019-354}, url = {https://www.nat-hazards-earth-syst-sci-discuss.net/nhess-2019-354/}, author = {Mercy Ndalila and Grant Williamson and Paul Fox-Hughes and Jason J. Sharples and David Bowman} } @article {bnh-5426, title = {Relicts at Risk: Impacts of the 2016 Tasmanian Fires on Pencil Pine (Athrotaxis Cupressoides)}, number = {459}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The main goal of this study is to obtain empirical measurements of fuel loads within the first year after a fire to complement the measurements of fuel loads taken directly before the fires.\  This will not only allow us to precisely quantify the fuel loads consumed by these relatively low-severity fires, but it will also give us a baseline measurement of fuel loads.\  We can use this baseline to anchor measurements of fuel accumulation in mature wet eucalypt forests that are part of related TERN and BNHCRC studies attempting to measure both the effects of climate and stand age on fuel accumulation in wet forests.\ 

}, keywords = {fire impacts, fire management, post-fire recover}, author = {Aimee Bliss and Lynda Prior and David Bowman} } @article {bnh-5425, title = {Understanding Post-Fire Fuel Dynamics using Burnt Permanent Forest Plots Report}, number = {461}, year = {2019}, month = {03/2019}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

The main goal of this study is to obtain empirical measurements of fuel loads within the first year after a fire to complement the measurements of fuel loads taken directly before the fires.\  This will not only allow us to precisely quantify the fuel loads consumed by these relatively low-severity fires, but it will also give us a baseline measurement of fuel loads.\  We can use this baseline to anchor measurements of fuel accumulation in mature wet eucalypt forests that are part of related TERN and BNHCRC studies attempting to measure both the effects of climate and stand age on fuel accumulation in wet forests.\ 

}, keywords = {ecology, ecosystems, Fire, Tasmanian fires}, author = {Furlaud, James M. and David Bowman} } @article {bnh-5259, title = {Can air quality management drive sustainable fuels management at the temperate wildland{\textendash}urban interface?}, journal = {Fire}, volume = {1}, year = {2018}, month = {08/2018}, abstract = {

Sustainablefiremanagementhaseludedallindustrialsocieties. Giventhegrowingnumber and magnitude of wildfire events, prescribed fire is being increasingly promoted as the key to reducing wildfire risk. However, smoke from prescribed fires can adversely affect public health. We propose that the application of air quality standards can lead to the development and adoption of sustainable fire management approaches that lower the risk of economically and ecologically damagingwildfireswhileimprovingairqualityandreducingclimate-forcingemissions. Forexample, green fire breaks at the wildland{\textendash}urban interface (WUI) can resist the spread of wildfires into urban areas. These could be created through mechanical thinning of trees, and then maintained by targeted prescribedfiretocreatebiodiverseandaestheticallypleasinglandscapes. Theharvestedwoodydebris could be used for pellets and other forms of bioenergy in residential space heating and electricity generation. Collectively, such an approach would reduce the negative health impacts of smoke pollutionfromwildfires,prescribedfires,andcombustionofwoodfordomesticheating. Weillustrate such possibilities by comparing current and potential fire management approaches in the temperate and environmentally similar landscapes of Vancouver Island in British Columbia, Canada and the island state of Tasmania in Australia.

}, url = {https://www.researchgate.net/profile/Sarah_Henderson4/publication/326955566_Can_Air_Quality_Management_Drive_Sustainable_Fuels_Management_at_the_Temperate_Wildland-Urban_Interface/links/5b6db08245851546c9fa2dab/Can-Air-Quality-Management-Drive-Sustainable}, author = {David Bowman and Lori Daniels and Fay Johnston and Grant Williamson and Matt Jolly and Sheryl Magzamen and Ana Rappold and Michael Brauer and Sarah Henderson} } @article {bnh-6321, title = {Geographic Patterns of Fire Severity Following an Extreme Eucalyptus Forest Fire in Southern Australia: 2013 Forcett-Dunalley Fire }, journal = {Fire}, volume = {1}, year = {2018}, month = {10/2018}, abstract = {

Fire severity is an important characteristic of fire regimes; however, global assessments of fire regimes typically focus more on fire frequency and burnt area. Our objective in this case study is to use multiple lines of evidence to understand fire severity and intensity patterns and their environmental correlates in the extreme 2013 Forcett-Dunalley fire in southeast Tasmania, Australia. We use maximum likelihood classification of aerial photography, and fire behavior equations, to report on fire severity and intensity patterns, and compare the performance of multiple thresholds of the normalised burn ratio (dNBR) and normalized difference vegetation index (dNDVI) (from pre- and post-fire Landsat 7 images) against classified aerial photography. We investigate how vegetation, topography, and fire weather, and therefore intensity, influenced fire severity patterns. According to the aerial photographic classification, the fire burnt 25,950 ha of which 5\% burnt at low severities, 17\% at medium severity, 32\% at high severity, 23\% at very high severities, while 22\% contained unburnt patches. Generalized linear modelling revealed that fire severity was strongly influenced by slope angle, aspect, and interactions between vegetation type and fire weather (FFDI) ranging from moderate (12) to catastrophic (\>100). Extreme fire weather, which occurred in 2\% of the total fire duration of the fire (16 days), caused the fire to burn nearly half (46\%) of the total area of the fireground and resulted in modelled extreme fireline intensities among all vegetation types, including an inferred peak of 68,000 kW{\textperiodcentered}m-1 in dry forest. The best satellite-based severity map was the site-specific dNBR (45\% congruence with aerial photography) showing dNBR potential in Eucalyptus forests, but the reliability of this approach must be assessed using aerial photography, and/or ground assessment.

}, keywords = {aerial photography, Eucalyptus forest, fire intensity, fire severity mapping, generalized linear modelling, geospatial validation, normalized burn ratio, Tasmania}, doi = {https://doi.org/10.3390/fire1030040}, url = {https://www.mdpi.com/2571-6255/1/3/40}, author = {Mercy Ndalila and Grant Williamson and David Bowman} } @article {bnh-4361, title = {Simulating the effectiveness of prescribed burning at altering wildfire behaviour in Tasmania, Australia}, journal = {International Journal of Wildland Fire}, year = {2017}, month = {12/2017}, abstract = {

Prescribed burning is a widely accepted wildfire hazard reduction technique; however, knowledge of its effectiveness remains limited. To address this, we employ simulations of a widely used fire behaviour model across the ecologically diverse Australian island state of Tasmania. We simulate three broad scenarios: (1) no fuel treatment, (2) a maximal treatment, with the most possible prescribed burning within ecological constraints, and (3) 12 hypothetically more implementable state-wide prescribed-burning plans. In all simulations, we standardised fire-weather inputs to represent regionally typical dangerous fire-weather conditions. Statistical modelling showed that an unrealistically large maximal treatment scenario could reduce fire intensity in three flammable vegetation types, and reduce fire probability in almost every vegetation type. However, leverage analysis of the 12 more-realistic implementable plans indicated that such prescribed burning would have only a minimal effect, if any, on fire extent and that none of these prescribed-burning plans substantially reduced fire intensity. The study highlights that prescribed burning can theoretically mitigate wildfire, but that an unrealistically large area would need to be treated to affect fire behaviour across the island. Rather, optimisation of prescribed burning requires careful landscape design at the local scale. Such designs should be based on improved fire behaviour modelling, empirical measurement of fuels and analysis of actual wildfires.

}, doi = {https://doi.org/10.1071/WF17061}, url = {http://www.publish.csiro.au/wf/WF17061}, author = {Furlaud, James M. and Grant Williamson and David Bowman} }