Review of forest fire intervals for planned burns and bushfires in South Eastern Australia

John O’Donnell

A review of bushfire disasters and forest fire intervals for planned burns and bushfires in South Eastern Australia has been prepared by John O’Donnell and is attached.  The author considers that the review is an essential component of learning from ongoing disastrous and intense bushfires and consequent impacts on communities, infrastructure, assets, plantations and the environment.

Click on the link below for the full article.

Fire-Interval-Review-4-Mar-24-2.pdf

Photo from an intense bushfire disaster in 2019/ 20 in central NSW with high fuel loads, its past time to move away from this outcome.

Preferred optimum fire intervals for forest burning is outlined in Section 2 of the review.

Current fire intervals in NSW are reviewed In detail in Section 3, including Sections 3.1 to 3.5 of the review. 

The author considers that current fire intervals, fire management and fire outcomes in NSW are not working effectively, as outlined in Sections 4.1 to 4.4.Section 4.1 is a broad assessment of failure areas in relation to restrictive fire interval criteria in NSW, identifying 17 failure areas.

It is suggested that there needs to be a total review of current fire intervals, noting current theoretical fire intervals set at very long timeframes that allows the build-up of high fuel loads and strata across landscapes and restricts low intensity burning across landscapes.   

There are differing time intervals for vegetation associations, flora species, fauna species and EEC’s across NSW.  It is extremely hard to manage prescribed burning under this complex fire interval approach considering all these matters and the very long fire intervals involved.  And importantly,  these fire intervals fail to address a large number of important issues as outlined in Section 4.1.

Large proportions of some vegetation associations that were burnt in the NSW 2019/ 20 bushfire firegrounds were wet sclerophyll forest types which are listed with very long fire intervals and have rapid rates of fuel accumulation.  This includes 51.24 % of Wet Sclerophyll (grassy sub formation) and 48.81 % of Wet Sclerophyll (shrubby sub formation).  These proportions were considerably higher than other vegetation associations burnt in the NSW 2019/ 20 bushfire.

In relation to the use of thresholds, there are large areas of contiguous similar threshold forest areas across eastern NSW, these are mapped in Map 22.2a and b of NSW SOE (2021).  These are often very large is size, this was a large factor in the rapid spread of the 2019/ 20 bushfires in long unburnt and within threshold areas.  The author suggests that a much better approach is using mosaic burning approaches to improve fire management and biodiversity across landscapes. 

Current theoretical fire intervals are not going to get us close to establishing and maintaining resilient forested landscapes in SE Australia.

The safety of fire fighters entering forested areas, particularly where there are high fuel loads, is a critical issue, and is a major risk area and has been for a long time.  The same observation applies in relation to the protection of  communities, including towns and cities, the safety of communities needs addition mitigation and focussed discussion with communities.  These matters and opportunities are raised in order to optimise the safety of fire fighters, communities, forests, the environment and heritage sites using regular low intensity fire and sensible fire interval prescriptions.

Other important words by Jurskis (2021) highlights the importance of urgent action to improve fire management:

We need a coalition of traditional knowledge; black, white and brindle, with fairdinkum science to restore sustainable management across the landscape. It would save heaps of money and reduce the massive emissions from megafires which aren’t brought to account because it doesn’t suit our Lock It Up and Let It Burn ‘conservation’ paradigm.

The author considers that regular burning every 3 to 6 years is needed across forested landscapes to reduce fuel loads and strata, intense bushfires and better protect sensitive areas, this reduces fuel loads and strata, firebrands and also reduces eucalypt decline.  Following high intensity burning and consequent dense regrowth in many cases, prescribed burns need to be undertaken as soon as possible after these intense bushfires to maintain previous forest structures and reduce massive fuel loads and strata.

The author considers that bushfire and prescribed burning, bushfire and fire interval prescriptions across forested landscapes should be redesigned into one practical fire prescription document, taking into account all the factors listed below:

1. A key focus on addressing the failures of current fire and bushfire fire and fire interval management across all land tenures and across landscapes;
2. A key focus on improved control of fire behaviour through management of fuel loads and strata and setting up fire resilient forests across all land tenures. Moist/ wet forests also have more rapid fuel accumulation that needs better considered and addressed.  Firebrands are another critical issue that need improved consideration;
3. A focus on recognising that the increasingly extensive high intensity fire regimes and eucalypt decline are consequences of fire exclusion;
4. A focus on reducing large area intense bushfire disasters and repeat intense bushfire disasters across all land tenures. There are way too much intense bushfires across NSW and SE Australia, the impacts of these fires are huge in relation to structure, integrity, sustainability, flowering, tree health and biodiversity.  Dead fuel and dense forest regrowth is resulting from many of these bushfires, further increasing bushfire hazards across large contiguous areas.  Yet these critical issues receive minimal attention;
5. A focus on avoidance of and management of large volumes of dead fuel and dense regrowth from intense bushfires across all land tenures;
6. A focus on improved planning for worst case bushfires, bushfire seasons, environmental impacts and costs of intense bushfires across all land tenures;
7. A key focus on setting up sound fire regimes for forests now and into the future and less focus on going back 60 plus years looking at past fire histories and intervals based on excessive fire return intervals;
8. A key focus on community, infrastructure and firefighter protection;
9. A key focus on government, community, landholder and individual fire management accountabilities across all land tenures;
10. Improved cooperative/ alliance approaches in firefighting and prescribed burning across all land tenures;
11. A key focus on cultural burning considerations is addressed;
12. A key focus on forested landscapes broken up by prescribed burning and treating 10 % of forested landscapes per year. Focus on mosaic burning with fuels of different ages across forested landscapes and avoidance of large areas of older contiguous fuels, strata and firebrands;
13. A key focus on establishment and maintenance of resilient forested landscapes, with healthy forests and maintenance of good condition vegetation associations;
14. A key focus on improving and maintaining forest condition, health and structures using regular low intensity fire as required;
15. A key focus on establishment of improved habitat for flora and fauna using low intensity fire and using mosaic burning approaches for benefit;
16.  Undertaking a review of the current focus on long interval requirements for individual threatened species and communities, at the expense of whole forested landscapes, with consequent heavy fuel loads and consequent intense bushfire disasters. Also undertaking a review of the policies of no low intensity fire in wilderness are other areas, this approach comes at a major cost when intense bushfires come around;
17. A key focus of improved protection of sensitive areas and heritage areas using low intensity burning;
18. A key focus on improved consideration on reducing major air quality and greenhouse impacts associated with intense, large area and long duration bushfires, and consequent deaths, such as during 2019/ 20; and
19. A key focus on improved consideration of research by Fasullo et al. (2023) in relation to the climate response to biomass burning emissions from the 2019–2020 Australian wildfire season subsequent multiyear ensemble mean cooling of the tropical Pacific is simulated through the end of 2021, suggesting an important contribution to the 2020–2022 strong La Niña events.

Its past time to incorporate the other important factors that haven’t been adequately considered into fire prescriptions, including reducing large area intense bushfires, adequately considering the impacts of large area intense bushfires, considering fuel build up, considering fire behaviour and suppression difficulty, adequately considering community and fire safety, addressing eucalypt decline and the other concerns outlined in this review.

The author considers that this review is an essential component of learning from ongoing disastrous and intense bushfires and consequent impacts on communities, infrastructure, assets, plantations and the environment.