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  • 1
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 25, No. 2 ( 2016), p. 158-
    Abstract: Most landscape-scale fire severity research relies on correlations between field measures of fire effects and relatively simple spectral reflectance indices that are not direct measures of heat output or changes in plant physiology. Although many authors have highlighted limitations of this approach and called for improved assessments of severity, others have suggested that the operational utility of such a simple approach makes it acceptable. An alternative pathway to evaluate fire severity that bridges fire combustion dynamics and ecophysiology via dose–response experiments is presented. We provide an illustrative example from a controlled nursery combustion laboratory experiment. In this example, severity is defined through changes in the ability of the plant to assimilate carbon at the leaf level. We also explore changes in the Differenced Normalised Differenced Vegetation Index (dNDVI) and the Differenced Normalised Burn Ratio (dNBR) as intermediate spectral indices. We demonstrate the potential of this methodology and propose dose–response metrics for quantifying severity in terms of carbon cycle processes.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2016
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  • 2
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 27, No. 7 ( 2018), p. 490-
    Abstract: Climate change is increasing drought and fire activity in many fire-prone regions including the western USA and circumpolar boreal forest. These changes highlight the need for improved understanding of how multiple disturbances impact trees in these regions. Recent studies linking fire behaviour to plant ecophysiology have improved understanding of how fire affects tree function and mortality but have not investigated interactions between drought stress and fire. In this study, Larix occidentalis saplings were subjected to different levels of water stress followed by low-intensity surface fires in a controlled laboratory setting. Post-fire mortality, recovery and growth were monitored for up to 1 year post fire. Generally, increased pre-fire water stress resulted in decreased post-fire stem diameter (up to 5% lower) and height (up to 19% lower) growth. However, severely water-stressed saplings whose foliage had senesced before the fires had lower 1-year mortality (14%) and significantly greater post-fire bud densities than moderately stressed saplings that did not senesce (86% mortality). The mortality patterns suggest that water-stressed western larch saplings exposed to low-intensity wildfires, or prescribed fires conducted as part of forest management activities, may exhibit lower mortality rates if stress-induced foliar senescence has occurred.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2018
    SSG: 12
    SSG: 23
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  • 3
    In: International Journal of Wildland Fire, CSIRO Publishing, ( 2014)
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2014
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  • 4
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 24, No. 1 ( 2015), p. 70-
    Abstract: Although fire is a common disturbance in shrub–steppe, few studies have specifically tested burned area mapping accuracy in these semiarid to arid environments. We conducted a preliminary assessment of the accuracy of the Monitoring Trends in Burn Severity (MTBS) burned area product on four shrub–steppe fires that exhibited varying degrees of within-fire patch heterogeneity. Independent burned area perimeters were derived through visual interpretation and were used to cross-compare the MTBS burned area perimeters with classifications produced using set thresholds on the Relativised differenced Normalised Burn Index (RdNBR), Mid-infrared Burn Index (MIRBI) and Char Soil Index (CSI). Overall, CSI provided the most consistent accuracies (96.3–98.6%), with only small commission errors (1.5–4.4%). MIRBI also had relatively high accuracies (92.2–97.9%) and small commission errors (2.1–10.8%). The MTBS burned area product had higher commission errors (4.3–15.5%), primarily due to inclusion of unburned islands and fingers within the fire perimeter. The RdNBR burned area maps exhibited lower accuracies (92.9–96.0%). However, the different indices when constrained by the MTBS perimeter provided variable results, with CSI providing the highest and least variable accuracies (97.4–99.1%). Studies seeking to use MTBS perimeters to analyse trends in burned area should apply spectral indices to constrain the final burned area maps. The present paper replaces a former paper of the same title (http://dx.doi.org/10.1071/WF13206), which was withdrawn owing to errors discovered in data analysis after the paper was accepted for publication.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2015
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  • 5
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 27, No. 4 ( 2018), p. 228-
    Abstract: Fire radiative energy density (FRED, J m−2) integrated from fire radiative power density (FRPD, W m−2) observations of landscape-level fires can present an undersampling problem when collected from fixed-wing aircraft. In the present study, the aircraft made multiple passes over the fire at ~3 min intervals, thus failing to observe most of the FRPD emitted as the flame front spread. We integrated the sparse FRPD time series to obtain pixel-level FRED estimates, and subsequently applied ordinary kriging (OK) and Gaussian conditional simulation (GCS) to interpolate across data voids caused by the undersampling. We compared FRED interpolated via OK and GCS with FRED estimated independently from ground measurements of biomass consumed from five prescribed burns at Eglin Air Force Base, Florida, USA. In four of five burns considered where undersampling prevailed, OK and GCS effectively interpolated FRED estimates across the data voids, improving the spatial distribution of FRED across the burning event and its overall mean. In a fifth burn, the burning characteristics were such that undersampling did not present a problem needing to be fixed. We also determined where burning and FRPD sampling characteristics merited applying OK and CGS only to the highest FRED estimates to interpolate more accurate FRED maps.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2018
    SSG: 12
    SSG: 23
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  • 6
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 27, No. 7 ( 2018), p. 498-
    Abstract: Fire radiative energy density (FRED, Jm-2) integrated from fire radiative power density (FRPD, Wm-2) observations of landscape-level fires can present an undersampling problem when collected from fixed-wing aircraft. In the present study, the aircraft made multiple passes over the fire at ~3min intervals, thus failing to observe most of the FRPD emitted as the flame front spread. We integrated the sparse FRPD time series to obtain pixel-level FRED estimates, and subsequently applied ordinary kriging (OK) and Gaussian conditional simulation (GCS) to interpolate across data voids caused by the undersampling. We compared FRED interpolated via OK and GCS with FRED estimated independently from ground measurements of biomass consumed from five prescribed burns at Eglin Air Force Base, Florida, USA. In four of five burns considered where undersampling prevailed, OK and GCS effectively interpolated FRED estimates across the data voids, improving the spatial distribution of FRED across the burning event and its overall mean. In a fifth burn, the burning characteristics were such that undersampling did not present a problem needing to be fixed. We also determined where burning and FRPD sampling characteristics merited applying OK and CGS only to the highest FRED estimates to interpolate more accurate FRED maps.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2018
    SSG: 12
    SSG: 23
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  • 7
    Online Resource
    Online Resource
    CSIRO Publishing ; 2010
    In:  International Journal of Wildland Fire Vol. 19, No. 6 ( 2010), p. 698-
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 19, No. 6 ( 2010), p. 698-
    Abstract: Vegetation fires produce biomass combustion residues, with colour varying from dark black char to white mineral ash. The colour-lightness of char and ash combustion residues is a qualitative parameter describing the post-fire condition of burned areas, and has been correlated with the completeness of combustion, fire intensity, and fire duration. Researchers have suggested that visual comparison of combustion residue samples with a standard grey scale would enable reliable combustion residue colour-lightness estimation. This paper describes an experiment aimed at assessing if colour-lightness can be estimated using a standard grey scale. Fifteen combustion residue samples with colour-lightness ranging from black char to white mineral ash were collected in the Northern Territory, Australia, and visually evaluated by three individuals using a grey scale. The grey-scale scores (0–19) were compared with the mean visible (390 to 830 nm) wavelength combustion residue reflectance (0–1) measured with a portable spectroradiometer. A significant linear relationship between the grey-scale scores and the mean visible combustion residue reflectance was found (R2 = 0.816 with a linear fit, R2 = 0.936 with a logarithmic-transformed fit). This finding suggests that combustion residue colour-lightness can be assessed in the field using inexpensive grey scales, and that this technique is a suitable avenue for future research on the field assessment of fire characteristics and effects.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2010
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  • 8
    In: International Journal of Wildland Fire, CSIRO Publishing, Vol. 23, No. 4 ( 2014), p. 532-
    Abstract: The Brazilian tropical moist forest biome (BTMFB) is experiencing high rates of deforestation and fire. Previous studies indicate that the majority of fires occur close to roads, however they did not consider the network of unofficial roads and navigable rivers, nor inter-state and inter-annual variability. We examine 8 years of Moderate Resolution Imaging Spectroradiometer (MODIS) active fire detections and the cumulative frequency distribution of the distance of each detection to the closest official road, unofficial road, and navigable river bank. Approximately 50 and 95% of all MODIS active fire detections occurred within 1 and 10km respectively of a road or navigable river. Inter-state and inter-annual variations are discussed and linkages to expansion of the road network are suggested. Comparison of the distance distribution of the MODIS active fire detections and the distance distribution of a 0.5-km spaced geographic grid to the combined roads and navigable river network revealed significant differences for each state and for the BTMFB and indicate that the great majority of fires are anthropogenic. The results provide insights that may be useful for modelling the incidence of fire under future expansion of the Amazonian road network and increased river navigability.
    Type of Medium: Online Resource
    ISSN: 1049-8001
    Language: English
    Publisher: CSIRO Publishing
    Publication Date: 2014
    SSG: 12
    SSG: 23
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