Fire Scar Report

A ‘fire scar’ is the visibly blackened land surface left after bushfires burn vegetation and leaf litter.

When viewed from space using satellite imagery, fire scars are usually visible as blackened or charred areas. Sometimes, if the satellite passes over the fire at the right time, the active fire front can be detected.

Remote sensing scientists use satellite imagery, which is captured on a regular basis, to identify and map fire scars by looking for changes in the landscape over time.

The fire scar maps and bar graphs were generated using information obtained from Landsat (1990 to 2016) and Sentinel (2017 to current) satellite imagery. Both the Landsat and Sentinel imagery are produced by the Queensland Government’s Remote Sensing Centre and reported on a monthly basis (https://www.qld.gov.au/environment/land/management/mapping/statewide-monitoring/firescar). The Landsat imagery has a resolution of 30m x 30m and Sentinel has imagery a resolution of 10m x 10m.

Note: Landsat images before 2013 may have more omissions of undetected fire scars or false fire scars due to issues such as cloud shadow and water bodies, as the older imagery has only had limited checking.

A range of fire scar maps and graphs describing fire scar seasonal distribution, fires detected in different years and fuel load information:

• a cumulative fire scar map for the period from 1990 to current, showing how many times fire scars were detected for an area during that period.

• a fire scars detected in each month for current year map.

• a years since burnt map showing how long ago the latest fire scar was detected.

• a graph that indicates the number of fire scars that occurred in different months in the past.

• a graph indicating the cumulative percentage fire scar area out of the total property area within an individual year.

• a graph relating the historical time series of curing index and fuel load for the property.

Be aware that NOAA satellite based imagery has broad scale resolution (approximately 1km x 1km), but provides daily revisits of a site from which fire scars can be detected.

Some fire scars may still be undetected by satellites due to:

• spatial or temporal limitation;

• "cool fires" under trees that don’t affect tree leaves; and

• Incidence of cloud cover.

"False fire scars" are also possible where land becomes dark due to cloud shadows or inundation of water.

The curing index is the percentage of dead pasture out of the total modelled pasture biomass. Both curing index and fuel load data were sourced from the AussieGRASS model outputs. The AussieGRASS model simulates regional scale historical time-series of rainfall and pasture growth, as well as projections for the season ahead, which are useful for forage budgeting and assessing impacts of drought and bushfire risk (see https://www.longpaddock.qld.gov.au/aussiegrass/about/).

All of the above factors need to be taken into consideration when interpreting the information presented in this report.

Fire scar information (spatially and temporally) can be used in land management by:

• adequacy of fire frequency for woody plant maintenance

• monitoring of carbon farming activities

• checking reduced fire frequency as an indicator of inadequate fuel load (e.g. signs of overgrazing)

• bushfire risk – monitoring fuel load build-up in woody areas

• general knowledge of past fire regime

• possible cause of low ground cover identified in imagery

• pasture species management and maintenance

For further information regarding fire management, see the Bioregional planned burn guidelines (DES/QPWS), which are based on Queensland’s thirteen Bioregions, addressing Fire Vegetation Groups (groups of related ecosystems that share common fire management requirements), and have been developed via expert panel and regional consultation https://parks.desi.qld.gov.au/management/programs/fire-management/guidelines.