This paper provides further evidence that the severity and extent of the Black Summer bushfires were primarily driven by climatic and meteorological factors. In particular, the authors note the role of extended drought, topography, and sustained hot windy weather.

This is consistent with prior research findings that highlight the influence of rugged terrain and critical fire weather in the development of extreme bushfires, and the diminishing influence that fuel load and structure have on fire propagation when weather conditions are at their worst.

Under such conditions, the spread of fire in forested areas is dominated by spotting and other fire-atmosphere feedbacks. During the 2019/20 bushfire season, the combination of severe drought, recurring episodes of critically low fuel moisture content, and the repeated occurrence of extreme fire weather associated with heatwaves and frontal systems resulted in the perfect conditions for catastrophic bushfire. 

The paper has many problems. The paper says there are no forest management effects, when in fact there ARE effects that are shown in their own data – Figure 3 of the paper. The title of the paper is highly misleading.

There is an extensive body of science that shows there are strong links between logging and fire severity and the data in this paper actually reinforces exactly that, despite the misleading title of the paper.
 
There are significant statistical problems with the way data were analysed – for example by combining cool fires with crown fires – which greatly weaken the analysis. Despite these problems they STILL found an effect of logging on fire severity!
 
This is a rather unfortunate paper, poorly framed, badly analysed, with the narrative actually not matching the data or the analysis.

Understanding the drivers of the 2019–2020 Australian forest fires is so important right now and this research provides a well-needed leap forward. By teasing apart the relative contributions of potential fire-drivers, the research shows just how important fire weather and features of the landscape are for predicting the chances of such devastating wildfires. It’s clear from this work that a long dry period leading up to the wildfires meant that the forests were primed and ready to ignite and burn severely.

The leaf litter was drier than it has been for 30 years in some places; forest fire danger indices were frighteningly high; and on top of all that the ongoing windy conditions and limited rainfall meant that the chances of such devastating forest fires were high. Strategic use of this sort of carefully put-together, evidence-based information is critical if we are to move forward in the new normal and prevent such events in the future.

A lot of work has already shown that crown fire is more likely in logged forests. Crown fires are beyond any capacity to control and lead to long-distance spotting, fast fire spread, and potentially pyrocumulonimbus storms. Instead of addressing that issue though, this study changed the focus to crown scorch. Even quite small flames can cause scorch, so it’s just not the same thing.

They did actually show that logging increases the likelihood of scorch so that logged forests were about as likely to scorch on mild days as undisturbed forests were on very high fire danger days. Despite that, they argued that logging still wasn’t an issue because it wasn’t responsible for the amount of scorch over the entire burnt area. Of course, no one has ever said it was; the concern is that where it happens, logging makes more crown fires that are impossible to control and have huge effects on the final size of the fire. This study didn’t address that at all.

The scale and impact of the Black Summer Fires on Australia’s forests was both ecologically and economically devastating. Therefore, the scientific community must demonstrate responsibility in accurately and honestly reporting the associated science.

The narrowly focussed and superficial science and opinion represented in the paper by Bowman et al. 2021 devalues existing knowledge on the impacts of climate change and of logging history in these forests. The authors have presented inadequate analyses, resulting in a confused message.

In other papers, the authors recognise that anthropogenic climate change has demonstrably increased the intensity, frequency, and severity of fires generally. This evidence is stronger than the emphasis on drought and dry soil conditions presented in this paper. Regardless of the well understood impacts of topography and climate change, the data presented show that logged and regenerating forests are burnt with greater severity.

The legacy of logging is widely recognised as one contributing factor to fire severity. It is not the only contributing factor. Logging changes forest structure, so that fire in logged forests increases fire severity, slowing ecological recovery. These impacts are expected to increase with global warming, and hence climate change.

A more thorough statistical analysis incorporating delayed and non-linear effects would have improved the clarity of the science in this paper."

The unprecedented scale of the 2019-20 wildfires in south-eastern Australia focused attention on how forest management might reduce their risks and impacts. Some argued that the severity and frequency of these fires were made worse by logging and associated forest management and that harvesting in native forests should cease to reduce fire risk. Little evidence from those fires has been presented to support these contentions.

This study provides a clear test of the hypothesis that logging increases fire severity, using data from areas burnt in 2019-20. Results indicated that the extent and severity of these fires was largely determined by 3 years of well below-average rainfall leading to dry fuels across all vegetation types, extreme fire weather conditions, and local topography.

Policy proposals to mitigate fire risks and impacts should be evidence-based and integrate multiple perspectives.  Traditional Indigenous knowledge, experience of local and professional fire managers, and the breadth of evidence from bushfire research should inform strategies for reducing bushfire impacts and increasing forest resilience and community safety.

This new research is very important because it points the finger squarely at human-induced climate change as the primary cause of the Black Summer bushfires of 2019/2020. The research shows that it was extreme fire weather, the combination of extremely hot, dry, windy weather, on top of a drought, that led to a bushfire catastrophe on a scale never seen before in Australia. Forest management – including whether there had been logging or prescribed burning in recent years – was of little importance.

 This research contradicts earlier work by researchers from the Australian National University, that suggested logging could increase the flammability of forests, increasing the likelihood of high-severity fires occurring. It seems likely that under very extreme fire weather conditions, such as those experienced in the summer of 2019/2020, the effect of forest management becomes irrelevant. Blaming land management practices for the Black Summer bushfires is wrong.
 
Alarmingly, this new research clearly suggests that under future climate change, bushfire catastrophes are likely to become more frequent, and there is very little that land managers will be able to do to prevent this. The most effective way to prevent future bushfire catastrophes is to take immediate, strong action to prevent further climate change.