Mapping fire severity in tropical savannas

Australia’s tropical savannas cover approximately 25%, or 1.9 million km2, of the continent, spanning Western Australia, the Northern Territory and Queensland. During the dry season, from May to October, fires occur frequently and can extend hundreds of kilometres.

In this context, it is easy to understand that strategic planning is vital for reducing harm to people, property and biodiversity. TERN’s AusCover facility is working closely with its partners in the region to make new remote-sensing data and information about fires and their effects available to support enhanced capabilities for fire management.

One of the new outputs is a fire-severity mapping product, which will provide more information about fires by describing their effect on vegetation. For example, it will allow researchers and fire managers to tell if a fire affected understorey vegetation or the tree canopy. This higher level of detail is important for determining the carbon emissions from savanna burning, as more intense fires burn more of the biomass and result in greater emissions. Dr Stefan Maier, an AusCover associate and Principal Research Fellow in Remote Sensing at Charles Darwin University, said the information about the severity of fires was also important from an ecological perspective.

‘Because fire is so prevalent and is a key driving force in Australian ecosystems, this information is crucial for all kinds of ecological research,’ Stefan says.

The new fire-severity product, which was developed in collaboration with the Bushfire CRC, combines AusCover’s remote-sensing data and satellite imagery from MODIS with extensisve field data from the Bushfire CRC that enabled calibration and validation of the product.

Dr Andrew Edwards of the Bushfire CRC undertook the field calibration as part of his PhD research. Andrew combined ground-based post-fire vegetation sampling with measurements taken from a helicopter using a handheld device with a sensor similar to the MODIS sensor on the Terra and Aqua satellites.

‘By correlating these datasets I was able to develop an algorithm for mapping fire severity from remotely sensed imagery,’ Andrew says.

The fire-severity mapping product will become available through the AusCover data portal in 2013. Land managers will be able to use it to monitor the effect of unplanned fires and strategically implemented burns. It will also provide researchers and conservation managers with greater information about the effects of fires on ecological communities, and improve estimates of carbon emissions resulting from tropical savanna fires.

The next step in the project will be to refine the product, and expand it to cover Australia’s rangelands – meaning that the tool will be available for land managers across more than 75% of Australia.

Published in TERN e-Newsletter November 2012

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