The claim

As Australia grapples with a horror fire season, questions are being asked about what was done — and what can be done in the future — to mitigate such devastating loss of life and property.

While some politicians, including Barnaby Joyce, have suggested a lack of hazard reduction burning may have exacerbated the severity of the fires, landscape flammability expert Philip Zylstra said it was "completely false to say there has been a lack of prescribed burning".

"Prescribed burning rates have increased markedly," Dr Zylstra, an adjunct associate professor at Curtin University, told ABC Radio.

"In NSW, the last decade has seen more than twice the amount of prescribed burning compared to the decade before and in all mapped records of prescribed burning across NSW national parks it's the highest decade."

Is that correct? RMIT ABC Fact Check considers the statistics.





The verdict

Dr Zylstra's claim is a fair call.

His claim resulted from an analysis of NSW National Parks and Wildlife Service (NPWS) fire data mapped against national park boundaries.

Experts said this was an appropriate way to see how much national parkland in NSW had been subjected to prescribed burns.

An independent analysis of the same data showed hazard reduction burning within national park boundaries increased 2.3 times — more than double — in the decade to 2018-19 compared with the preceding 10 years.

The analysis also showed a larger area of national parkland was burned over the course of the decade than in any preceding decade.

Further, the numbers showed all prescribed burning covered by the NPWS data, including burns outside national park boundaries, also increased 1.9 times when comparing the two most recent 10-year periods.

It's a fair call to say that twice the amount of land was burned this decade compared to the previous. ( Supplied: NSW RFS )

What is prescribed burning?

Prescribed burning, variously called "hazard reduction burning" or "controlled burning", is the planned and purposeful burning of excess ground litter and fuel hazards in a specific area.

Hazard reduction burning should not be confused with "backburning", which is a last-resort measure used during fire fighting efforts to prevent the spread of bushfires.

Since 2011, the NSW Government has committed to treating 135,000 hectares of bushland on average per year.

Fact Check previously explained hazard reduction burns in depth in a fact file on the issue.

The source of the claim

Dr Zylstra told Fact Check he had used NSW Government spatial data for the basis of his claim, and pointed to data available online that he believed to be the same as that provided to him.

The online data comes from the NSW National Parks and Wildlife Service (NPWS), which carries out 75 per cent of hazard reduction burning in NSW. A document attached to the data notes that fires included in the dataset "often extend outside NPWS estate".

The dataset is available in the form of mapping data which can then be viewed and explored in online mapping software called the SEED (sharing and enabling environmental data) portal.

Fact Check contacted the Department of Planning, Industry and Environment regarding the dataset and was told "the SEED data is only a subset of the total fire data available" and to contact the NSW Rural Fire Service for comprehensive figures.

In a statement, a spokeswoman for the department told Fact Check:

"The SEED portal has been developed to, over time, provide open access to all NSW environmental data. With respect to hazard reduction datasets, SEED provides access to information on hazard reduction deemed relevant to the National Parks and Wildlife Service (NPWS). Importantly, NPWS data is only a subset of all NSW hazard reduction data.

"While SEED will continue to expand the range of environmental data that can be accessed through its portal, at this time the NSW Rural Fire Service (RFS) should be the source for complete fire history data for all NSW agencies and across all tenures."

Prescribed burning aims to reduce the amount of fuel available for future bushfires to spread. ( Supplied: NSWRFS )



The NPWS numbers

Fact Check accepts that Dr Zylstra's claim was essentially referring to prescribed burning in national parks, rather than the whole of NSW.

Despite the limitations outlined by the Department of Planning, Industry and Environment spokeswoman, Fact Check has used the NPWS SEED data to analyse Dr Zylstra's claims of increased burning within national parks.

In order to analyse prescribed burning in national parks only, Dr Zylstra used a national parks map to confine prescribed burns outlined in the NPWS data to park boundaries.

"That would mean that I reported the area of NPWS estate burnt, whereas they reported the [total] area burnt by NPWS," Dr Zylstra explained.

Dr Zylstra's analysis showed that in the 10 years to June 30, 2019, 668,191 hectares of NSW national parkland was burned in NSW.

That compares to 279,039 hectares in the preceding 10 years, in line with Dr Zylstra's claim that "the last decade has seen more than twice the amount of prescribed burning compared to the decade before".

In each other decade in Dr Zylstra's analysis, the area of national parks burned in hazard reduction fires was less than in the 10 years to 2018-19.

Checking the numbers

Fact Check asked Amy Griffin, a senior lecturer in geospatial sciences at RMIT University, to independently analyse the publicly-available NPWS data.

Her figures, while differing slightly from Dr Zylstra's numbers, showed the same overall trend in hazard reduction burning inside NSW national parks.

"You can say with confidence the trend identified [by Dr Zylstra] is accurate," Dr Griffin told Fact Check.

When comparing the 10-year period to 2018-19 with the preceding 10 years, Dr Griffin concluded that there had been an increase of 2.3 times in the amount of prescribed burning — close to Dr Zylstra's claim of a two-times increase.

In addition, Dr Griffin provided Fact Check with annual figures for the number of hectares of NSW national parks subjected to prescribed burns.

"Summarising the data by decade masks differences year-to-year," she told Fact Check, adding that years with less prescribed burning seemed to correspond with known drought years.

Queensland Fire and Emergency Services Superintendent James Haig has previously told Fact Check that the most common reason for a permit for hazard reduction burning not being granted was due to dry conditions which made such action unsafe.

What about total area burned?

Dr Griffin also analysed the NPWS data for the total area burned, including where hazard reduction burns extended outside national park boundaries.

Those figures, like the figures for just the national parks, show the area of land burned in prescribed fires in the decade to 2018-19 was nearly double the area burned in the preceding 10 years.



The largest area covered by all prescribed burning in a 10-year period did not occur in the most recent period; Dr Griffin's numbers show the area burned in the decade 1979-80 to 1988-89 exceeded the area burned from 2009-10 to 2018-19.

The RFS figures

The NSW RFS provided Fact Check with hazard reduction statistics dating back to 2004-05.

As previously mentioned, the RFS statistics provide a more complete picture of areas subjected to prescribed burns, though the limited timeframe of those figures does not allow for a comparison in 10-yearly increments.

Notwithstanding, the data does show an upwards trend in hazard reduction burning over the past 15 years.

What do the experts say?

Geospatial mapping experts told Fact Check that Dr Zylstra's method was an appropriate way to analyse the available data.

Eleanor Bruce, an associate professor in the Faculty of Science at the University of Sydney, told Fact Check "the spatial analysis techniques described here are appropriate".

"I would also use [geographic information systems]-based intersect analysis outlined by Dr Zylstra," said Dr Bruce, whose research interests are in environmental spatial analysis and modelling.

Philip Gibbons, of the Fenner School of Environment and Society at the Australian National University, looked at both Federal Government data relating to fires in forests as well as the NPWS data in order to evaluate the Dr Zylstra's claim.

"Although the total areas are in disagreement, both data sources basically support the assertion that hazard reduction burning has approximately doubled within NSW in the last decade relative to the one before it," Professor Gibbons said.

An expert in forest management and ecological sustainability, Dr Gibbons added that it was "wrong to castigate state agencies" for not meeting hazard reduction targets as they were difficult and dangerous to achieve in periods of drought, and less meaningful than more strategic targets such as burning nearer to houses.

"Pushing state agencies to chase area targets results in large, hazard reduction burns in remote areas where they are easy to execute — as happened in Victoria in the first years after the Bushfires Royal Commission — rather than strategic hazard reduction burning close to houses where they are more effective as indicated by our research."

Principal researcher: Ellen McCutchan

factcheck@rmit.edu.au



Editor's note (February 5, 2020): A graph in a previous version of this fact check contained figures, supplied by the RFS, for both burning and mechanical hazard reduction activities rather than just prescribed burns as it was labelled. This graph has been amended with the correct figures. The headline of the fact check was also amended to better reflect the parameters of Professor Zylstra's claim, as he referred to national parks. This does not change our verdict.

Sources