Questionable environmental science and ill-informed eco-activism now endangering Australia's forests

In recent weeks, the media has reported on so-called 'landmark research' co-authored by ANU ecologist, Professor David Lindenmayer, and Curtin University environmental scientist, Associate Professor Philip Zylstra, which asserts that prescribed fuel reduction burning intended to reduce forest fire risk, can have the opposite effect by increasing forest flammability.

Their paper was published in December 2023 in an online access journal, Biological Reviews, which, according to its website, only publishes "synthetic reviews …. that comprehensively surveys the literature in order to answer a key biological question, or to identify new biological questions that need to be addressed to advance the field". The journal's website also makes it clear that its published reviews do not constitute primary research, which must include new data. Furthermore, co-author Philip Zylstra, has been publishing similar findings about forest flammability since at least 2018. This somewhat puts the claim of 'landmark research' into perspective.

The paper was publicly launched via an ANU media release just a week before the start of a Federal Court case in which environmental group, Save Our Strathbogie Forest, is seeking to overturn Victorian Government plans to conduct fuel reduction burns in local forests during the 2024 autumn period. According to a media report, the environmental activists claim that these burns pose a 'catastrophic risk' to a population of southern greater gliders.

Until now, most criticism of prescribed fuel reduction burning has been focused on claimed impacts to native flora and fauna and/or on the failure of burns to limit bushfire outcomes as they are expected to do. So, the Lindenmayer-Zylstra theory that prescribed burning actually worsens the bushfire risk, represents a fresh new argument for those railing against it.

According to the accompanying ANU media release, the Lindenmayer-Zylstra theory challenges the contemporary forest management notion that broadscale interventions are necessary to manage fire risk, and exemplifies the need "for a greater connection between forestry and fire science to understand how fire prevention strategies affect the natural environment".

This could be construed as implying that forestry and fire science are not closely connected even though serious concerns about damaging bushfires have been integral to organised forest management (ie. forestry) since its inception over a century ago. Accordingly, forestry agencies and fire scientists have been researching and refining all aspects of the prevention and control of forest fire for generations, including observing and understanding its impacts on the natural environment.

Their most important learnings have been that: (1) any adverse environmental impacts associated with periodic fuel reduction burning pales into insignificance against the catastrophic environmental impacts that occur when long unburnt forests carrying heavy fuel loads are incinerated in hot mid-summer bushfires; and (2) that previously fuel reduced forests are significantly less affected than long unburnt forests when hot mid-summer bushfires pass through them.

Unfortunately, these fundamental realities do not seem to register amongst those opposed to broadscale fuel reduction burning. This suggests that the greater need for a meaningful connection is actually between forestry authorities who bear the burden of responsibility for fire management, and those environmental scientists and eco-activists who oppose fire management strategies generally from a comfortable 'all care- no responsibility' stand-point.

If such a connection could be achieved, then perhaps intending critics of fuel reduction burning could better understand how cool season controlled fire differs from uncontrolled hot summer bushfires; its wider context and proportional scale; how it is planned and conducted in the face of many natural and societal variables; the many documented instances of its benefit in facilitating bushfire control; the adverse ecological and potential human consequences of not burning; and the practical and/or cost-effective shortcomings of mooted alternatives.

From a forestry perspective, there is a disturbing lack of practical understanding about forest fire management amongst critics of prescribed fuel reduction burning. This is somewhat exemplified by Lindenmayer and Zylstra's thoughts on how forest fire risk can be ameliorated in the absence of broadscale fuel reduction burning. They believe forests can grow old free from any disturbance by fire (either prescribed or unplanned) to thereby become more fire resistant. This prolonged absence of fire can supposedly be achieved through greater investment in AI and drone technology to quickly detect and fight bushfires.

Irrespective of their scientific reasoning, a century of organised forest management suggests that achieving a prolonged absence of fire from most Australian forests would be impossibly at odds with nature. Apart from the small proportion that grow in very wet areas, the vast bulk of Australia's forests and woodlands occupy relatively dry landscapes and are comprised of vegetation that has been shaped by thousands of years of regular fire. Indeed, the south-eastern corner of the continent is one of the world's top three most fire-prone regions, and the historical record of explorers and early settlers is full of accounts of fires burning on a far more extensive scale than modern times where we actively suppress bushfires during the warmer months.

The historical record also suggests that prior to European settlement, most fire in the landscape was of low intensity (similar to prescribed burning) because the frequency of ignitions from indigenous cultural activity and due to lightning, coupled with a lack of any control other than rain, meant that all but the wettest parts of the forested landscape, were being so regularly burned as to be maintained in a low fuel state. This effectively made them more resistant to the ecologically damaging high intensity bushfires that are commonplace today, and directly contradicts the Lindenmayer-Zylstra theory that it is a long absence of fire that creates landscapes that are more resistant to fire.

From a forestry perspective, an expectation that investing in drones and AI technology can dramatically improve bushfire outcomes reflects a limited understanding of the complexities of bushfire control. The advocacy of AI technology to more quickly detect bushfires assumes that already quick detection of fires and rapid response can be significantly improved upon. Even if true, while slightly quicker fire detection may improve control of bushfires that can be quickly accessed in well-roaded plantations or near towns; it would make little difference to the remote area fires that are more likely to develop the size and momentum to cause catastrophic environmental outcomes.

In these remote area fires, the limiting factors that generally determine successful fire control are the availability of ground-based fire-fighting resources and the speed at which they can reach the fire-ground. This is dependent on the nature of the topography and the highly variable quality and maintenance of the road and track network which, in this era of increasing national park declarations, frequently includes closed-off, over-grown, or unusable tracks due to unmaintained drainage infrastructure, such as log bridges. Given that overcoming such constraints is often measured in multiple hours, using AI technology to detect a bushfire a minute or two earlier than conventional detection methods, would make little overall difference to fire response and control outcomes.

The advocacy of drones is perplexing. While they could be useful in an observational role, the prospect of drones carrying water to extinguish going bushfires is fanciful given that not even helicopter or fixed wing water bombers dropping far larger payloads are generally capable of doing much more than temporarily halting the spread of small remote forest fires, or holding parts of the perimeter of a larger fire. The main benefit of aerial water bombing is in saving houses and properties when bushfires adjoin towns or suburbs. They can assist remote area fire suppression, but are not a panacea for conventional ground-based fire control strategies.

The already huge annual expenditure on aerial water bombing capability is often cited as a reason for the decline in funding for off-season preventative measures such as prescribed burning. It has been noted elsewhere that despite a dramatic expansion of aerial fire-fighting capability over the past 20 years, the incidence and extent of hot summer bushfires has significantly increased, rather than declined as had been envisaged.

It has been said that criticising fuel reduction burning for not stopping bushfires is akin to criticising seat belts because people still die in car accidents. The aim of fuel reduction is to reduce fire intensity and thereby improve the capability for fire control, which can then result in improved outcomes for human life and property, as well as the environment, if fires can be contained and extinguished sooner rather than later.

The real problem with fuel reduction burning is that not enough of it is being done. This has been a recurring theme in the dozens of public inquiries arising from the aftermath of major bushfire disasters. Small isolated fuel reduced patches or narrow strips are easily by-passed or overwhelmed by large intense bushfires, whereas large, contiguous blocks of reduced fuels can and often do stop or significantly slow large fires under most circumstances, thereby improving the chances for control. There were many examples of this during the 2019-20 'Black Summer' bushfires.

Recently it was reported that record numbers of native species were added to the national threatened species list last year. Apparently over the last two years, 223 threatened species and eight ecological communities have been added to the threatened species list. Of these, 130 were bushfire-affected species and eight were bushfire-affected ecological communities, largely arising from the 2019-20 bushfires. It is highly likely that this outcome would have been substantially mitigated if we were doing sufficient broadscale fuel reduction burning to significantly ameliorate the extent of hot summer bushfires.

Given that unnaturally severe bushfire ranks with introduced feral animals and weeds as the greatest threats to Australian forest ecology, and that prescribed burning is a major tool employed to mitigate it, there are potentially very dangerous consequences attached to calls by environmental scientists and eco-activists that it be sidelined in favor of theoretical or unproven fire management approaches. Forest fire management is best left to the specialist field practitioners and fire scientists with genuine experience, understanding and insight into what will or won't work.