Main Club, 4 April 2025

Peta Kelsey was our guest speaker. Peta has worked in the Antarctic and Fiji as a geophysicist. She has also worked at Curtin University and the Department of Water and Environmental Regulation (DWER) in WA, where she modelled groundwater, catchments and estuaries. On retirement, Peta took an interest in prescribed burning in the SW forest region of WA and, as a member of the South-West Forests Defence Foundation (SWFDF), published a booklet called Prescribed Burning Fact Sheets. This can be found at the SWFDF website.

The Department of Biodiversity, Conservation and Attractions (DBCA) carries out its prescribed burning (PB) program over the SW Forests area. The Department mainly aims to minimise property damage and protect people from wildfires. They also claim that prescribed burning benefits biodiversity.  Depending on the location, they have annual targets for the area to be burnt. Burning close to settlements has to be managed more intensively and carefully, so costs per hectare are greater. 

Peta pointed out the many adverse ecological consequences of PB. Burning stimulates understorey growth, increasing fuel load and making the bush susceptible to higher intensity and more severe wildfire. The prescribed burning kills many animals and destroys habitats like old trees with nesting hollows. Prescribed burns are carried out by dropping Incendiaries in such a way that it makes it difficult for animals to escape.

Peta said that the burns are often as severe as a wildfire. She says that DBCA often burns in sensitive areas, which is contrary to their mission statement, and that they are not prohibited from killing threatened species. Tens of thousands of animals are impacted annually, including nesting birds. If burning is too frequent, plants and animals that need long recovery times from fire are severely impacted. 

On average, Peta says that previously (1952–2004), the 200,000ha annual PB had prevented about 50,000ha of wildfire (a ratio of 4:1). Now, using a larger data set (1952–2020), the effectiveness of PB in preventing subsequent wildfire has been about 50:1, so annually it now prevents about 4000ha of wildfire. This data suggests that PB is very low in effectiveness and a dreadful waste of money, apart from the damage it causes. Peta says that DBCA is undertaking the cheapest possible program to burn the largest area. The recent annual costs have been $52 million each year to burn on average177,000ha. 

Additionally, there are hidden costs caused by the smoke—human deaths and illness, effects on tourism, and harm to the honey and wine industries. Ambient air quality laws don’t apply to PB. Then there are the 8 million tonnes of CO2 emitted each year (8–10% of WA’s emissions), which exacerbate Global Warming. These emissions are not reported in the annual greenhouse gas report.

Could there be better ways to minimise wildfires, such as technology for early detection and rapid response?

Mike Gregson