@article {bnh-7907, title = {High-Resolution Estimates of Fire Severity - An Evaluation of UAS Image and LiDAR Mapping Approaches on a Sedgeland Forest Boundary in Tasmania, Australia }, journal = {Fire}, volume = {4}, year = {2021}, month = {03/2021}, chapter = {14}, abstract = {

With an increase in the frequency and severity of wildfires across the globe and resultant changes to long-established fire regimes, the mapping of fire severity is a vital part of monitoring ecosystem resilience and recovery. The emergence of unoccupied aircraft systems (UAS) and compact sensors (RGB and LiDAR) provide new opportunities to map fire severity. This paper conducts a comparison of metrics derived from UAS Light Detecting and Ranging (LiDAR) point clouds and UAS image based products to classify fire severity. A workflow which derives novel metrics describing vegetation structure and fire severity from UAS remote sensing data is developed that fully utilises the vegetation information available in both data sources. UAS imagery and LiDAR data were captured pre- and post-fire over a 300 m by 300 m study area in Tasmania, Australia. The study area featured a vegetation gradient from sedgeland vegetation (e.g., button grass 0.2m) to forest (e.g., Eucalyptus obliqua and Eucalyptus globulus 50m). To classify the vegetation and fire severity, a comprehensive set of variables describing structural, textural and spectral characteristics were gathered using UAS images and UAS LiDAR datasets. A recursive feature elimination process was used to highlight the subsets of variables to be included in random forest classifiers. The classifier was then used to map vegetation and severity across the study area. The results indicate that UAS LiDAR provided similar overall accuracy to UAS image and combined (UAS LiDAR and UAS image predictor values) data streams to classify vegetation (UAS image: 80.6\%; UAS LiDAR: 78.9\%; and Combined: 83.1\%) and severity in areas of forest (UAS image: 76.6\%, UAS LiDAR: 74.5\%; and Combined: 78.5\%) and areas of sedgeland (UAS image: 72.4\%; UAS LiDAR: 75.2\%; and Combined: 76.6\%). These results indicate that UAS SfM and LiDAR point clouds can be used to assess fire severity at very high spatial resolutio

}, keywords = {3D remote sensing, drone, fire severity, fuel structure, Lidar, photogrammetry, RPAS, structure, UAS, vegetation}, doi = {https://doi.org/10.3390/fire4010014}, url = {https://www.mdpi.com/2571-6255/4/1/14/htm}, author = {Samuel Hillman and Bryan Hally and Luke Wallace and Darren Turner and Arko Lucieer and Karin Reinke and Simon Jones} } @article {bnh-7889, title = {Optimisation of fuel reduction burning regimes for fuel reduction, carbon, water and vegetation outcomes {\textendash} final project report}, number = {648}, year = {2021}, month = {03/2021}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Fire managers often have multiple objectives for a given prescribed burn centred around risk reduction and conservation of biodiversity. The ability to predict the effects of prescribed burning on the capacity of forests to deliver ecosystem services such as clean air, carbon sequestration, and a reliable and high-quality supply of water is becoming increasingly more important.

The body of research detailed in this Synthesis Report represents a concerted effort to understand the effect of prescribed burning on water quantity and carbon losses and gains in forested ecosystems in south-eastern Australia. We collected empirical data from over 100 sampling sites treated with a recent prescribed burn. The sampling strategy we used was consistent over time with target sampling variables included for estimation of overstorey and understorey biomass and direct sampling of surface and near surface fuel loads. Site selection was stratified to accommodate as much site variability as possible and to take full advantage of prescribed burn plans.

Data collected from the field was used in a variety of modelling assignments to capture the effect of prescribed burning on changes in water availability and transformation of carbon pools. Using a mixture of models and empirical sampling and analysis, we showed that there are few risks to long-term carbon and water cycles when prescribed burning is conducted on cycles of 10 or so years. Critical to this analysis is the frequency of bushfires {\textendash} if the inter-fire interval of unplanned fires becomes short (e.g., \<50 years) then ecosystem losses of carbon and reductions in water yield are likely to become semi-permanent features.

Our modelling endeavours ranged from relatively complex process-based models describing water and carbon balances through to simple response surface models. By exploring the transformation of carbon pools in surface fuels during prescribed burning, we developed robust yet simple-to-use models for predicting changes in total carbon and biomass in this fuel fraction. The novel application of FullCAM, a well-established model used for carbon accounting, was tested for its ability to incorporate often subtle changes in forest growth and carbon transformation associated with prescribed burning. We found this model to be relatively sensitive and recommend it to fire managers for applications such as estimation of carbon emissions. Based on our key findings, we advocate for continued research and evidence-based application of prescribed burning as a valuable land management approach.

Data assembled from peer-reviewed publications and researchers worldwide was mined for changing trends in publications concerning prescribed burning, global patterns of litterfall and standing litter, and water use efficiency of forests. These summative studies informed our research direction and chartered our progress.

A considerable number of student projects have been supported during the course of this project contributing to the training of the next generation of researchers and land managers.

}, keywords = {burning regimes, carbon, fuel reduction, optimisation, vegetation, water}, issn = {648}, author = {Bell, Tina and Adams, Mark A. and Mathias Neumann and Danica Parnell and David Pepper and Malcolm Possell} } @article {bnh-7299, title = {Optimisation of fuel reduction burning regimes for fuel reduction, carbon, water and vegetation outcomes: annual report 2019-2020}, number = {606}, year = {2020}, month = {09/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

We have made good progress over the past 12 months and have completed a number of milestones. Fieldwork and analysis of associated samples has ben completed and the data sets generated have formed the basis of our modelling efforts. Research has included: (i) landscape-scale modelling of the effect of prescribed burning on evapotranspiration as the main driver for water use by vegetation; (ii) calibration and testing of FullCAM, a process-based model that can track carbon pools in forests systems, that we have shown is sensitive enough to integrate changes due to prescribed burning; (iii) testing of a fine fuel model that can be used to determine changes in biomass (fuel load) and carbon content in surface fuels without laborious sample collection and analysis; and (iv) use of near infrared spectroscopy to determine fire intensity and severity.

Modelling using FullCAM and the fine fuel model are tools that have very good potential to be adopted by end-user agencies when required to report on carbon emissions resulting from their efforts to manage fuels. For example, the fine fuel model is an easy-to-use tool that can be used as a guide for estimating potential for carbon loss due to prescribed burning. Our recent advances with near infrared spectroscopy of fire residues suggests that the next steps will be to move from a laboratory setting to the field to test the efficacy of hand-held devices. The potential to develop a simple, yet accurate method for determining fire intensity would aid in ground-truthing of fires to replace current methods that are mostly subjective.

Reporting on our progress has taken the form of milestone reports (draft reports and Technical Reports), bi-monthly newsletters directed towards our end-users, and presentations for local, national and international audiences. We have endeavoured to meet regularly with our primary end-user and have continued collaborations with research groups such as CSIRO and local land managers from NSW National Parks and Wildlife Service. As our project ends, we will produce a synthesis of our research and will develop it further for peer-review publications.

}, keywords = {burning regimes, carbon, fuel reduction, vegetation, water}, issn = {606}, author = {Bell, Tina} } @article {bnh-6978, title = {Quantifying the conversion of vegetation to ash for soil carbon fingerprinting}, number = {572}, year = {2020}, month = {06/2020}, institution = {Bushfire and Natural Hazards CRC}, address = {Melbourne}, abstract = {

Samples of leaves, twigs and bark representing typical surface fuels from forests and woodlands were systematically heated and combusted under controlled conditions. Very little biomass, carbon (C) and nitrogen (N) was lost when heated at low temperatures to 200 {\textdegree} and greatest losses occurred between 400 and 600

{\textdegree}C, regardless of the type of fuel burnt. Losses of C and N varied considerably with temperature. Carbon was lost when fuels were heated at temperatures of 300 {\textdegree}C or more. Nitrogen was relatively more abundant when heated at 400 {\textdegree}C, albeit at very low levels (less than 5\%). When heating time was varied there were noticeable differences in patterns of weight loss and changes in proportions of C and N. This indicates that both fire intensity and residence time is likely to be important in understanding losses of C and nutrients during fire, particularly during low intensity prescribed burning.

The use of colour of residues after heating surface fuel has the potential to determine fire severity. Existing technology such as near infra-red scanners can measure ash colour, not only indicating fire severity but also, by association, C and N losses from fire. Combustion studies done in a well-controlled laboratory environment could be used to interpret fireground conditions in relation to fire intensity and residence time, according to the nature and amount of charred material, charcoal and ash that remains after fire.

}, keywords = {Ash, milestone, soil carbon fingerprinting, vegetation}, issn = {572}, author = {Danica Parnell and Bell, Tina and Malcolm Possell} } @mastersthesis {bnh-5779, title = {Effects of Sydney coastal dry sclerophyll forest litter on fuels and fire behaviour in Hornsby shire}, volume = {Masters of Philosophy}, year = {2019}, month = {02/2019}, school = {The University of Sydney}, type = {Masters}, address = {Sydney}, abstract = {

Globally bushfires are an ecological phenomenon that can cause deaths and widespread destruction of assets such as homes, utilities and essential infrastructure. Bushfires usually start in forest litter on a forest floor. The research described in this thesis used empirical data to characterise the physical and chemical attributes of litter, a component of forest and woodland fuels that is particularly important for propagation of fire. Differences in the amounts, arrangement and flammability of components of litter were determined for Sydney Coastal Dry Sclerophyll Forest, a common vegetation type in the Sydney Basin. Surface litter was investigated at study sites at Rofe Park, Hornsby Heights and Halls Creek, Arcadia, New South Wales, Australia.

}, keywords = {bushfires, coastal fire, flammability, litter, rubbish, Sydney, vegetation}, author = {Angela Gormley} }