FOBIF and Forest Fire management: a list of differences

FOBIF and Castlemaine Field Naturalists representatives met with fire officers in the Fryers Forest in February to discuss differences of opinion about fire. The discussion was lengthy and clarified [again] the difference in outlook of the two groups. The following points of contention were discussed:

1. The question of litter as a dangerous fuel .
2. The question of tussocks as fuel
3. The question raised by research: do long unburned forests burn less fiercely in bushfires?
4. The question of damage caused by canopy scorch.
5. The destruction of big trees in management burns, both accidental and deliberate
6. Fire and forest health: what do we know about the long term effect of management burns, both on biodiversity and on flammability?
7. The consequence of rating public safety as ‘number one’, and environmental health ‘number two’: does this inevitably lead to biodiversity damage in remoter forests?
8. A subject which didn’t come up: how the zoning system works. In particular, what’s the rationale behind ‘burn exclusion zones’?
9. Small burns/large burns: what’s the desirability and practicality of these?

Here are some details:

Litter

For managers, 75% of the fuel danger lies in surface and near surface fuels—ie, litter. There are two perspectives on litter:

                                                    a.

–Hawkeye research has proposed that three years after a reduction burn, leaf litter levels are the same in adjacent unburned areas as they are in burned areas. The reason for this is that litter is processed and reduced into soil by invertebrates, so that it never builds beyond a certain level. Any gardener using mulch is familiar with this process.

–However, fire officers believe that the litter build up after three years would be about 3.5 cm. According to The Department’s Fuel hazard assessment guide this is a ‘very high’ to ‘extreme’ fuel hazard.

This means that to be truly effective, reduction burns would have to be conducted at least every three years. The minimum tolerable fire interval in our forests is 10-15 years, though it could be much higher in more severe conditions.

To burn more often would be to radically change the nature of the forest, and not for the better.

The apparently irresolvable difference is that conservationists see enormous value in leaf litter—as habitat for invertebrates.

There’s a worldwide dimension to this: the decline in insect populations…See, for example: The insect crisis, by Oliver Milman. This is not a trivial matter, as widespread anxiety about bees has shown. Threats to bees might be the least of the problem.

Fire officers, on the other hand, see litter as menacing fuel. It’s hard to see how these two positions can be reconciled.

Tussocks

According to The Fuel hazard assessment guide, tussocks are at the ‘very high’ or ‘extreme’ danger level when they cover more than 40% of the ground, and more than 30% of the fronds are dead. We didn’t clarify how many of our tussocks carry lots of dead fronds. We need to get more info on this one. We also need to clarify what species of tussock are involved here: not all tussocks are equally flammable.

In any case, the assessment of tussocks as high fuel danger has to depend on many factors. The conflict here is similar to that about litter: conservationists believe that perennial grasses retain moisture in the soil, particularly on slopes; they prevent or control erosion; and they are also habitat for insects.

An interesting case study in this area is the burning of the slopes of Tarilta Gorge in 2012: this was followed by massive soil loss when heavy rain followed the burn.

The effect of fire on soil biota, including fungi, doesn’t feature in these discussions: we’d like to see some monitoring figures on this.

Does long unburnt bush burn less fiercely?

Research by Phil Zylstra and David Lindenmayer proposes that long unburnt bush burns less fiercely in a bushfire than bush that’s been ‘fuel reduced.’

This research is dismissed as ‘academic’ by some [most?] managers.

We’re not impressed to hear university research dismissed as ‘academic’. The question is a factual one: is it, or isn’t it true that unburned forests suffered less in recent bushfires than burned ones?  This seems to run contrary to Department modelling, which purports to show that ‘bushfire risk rose steadily after the devastating 1983 Ash Wednesday bushfires as fuel re-accumulated across the state, reaching a peak of 81% in 2002.’ . We’re not sure what ‘81%’ means.

Modelling is one thing: the facts of experience are another: do unburned forests burn less fiercely than ‘fuel reduced’ ones, or not?

Managers cite experience of seeing bushfires halted or moderated by fuel reduced areas. As far as we can tell, these fuel reduced areas are usually only 1-2 years old. Conservationists have to deal with heartfelt statements by managers about the lifesaving effects of reduction burns.

Our compromise position is acceptance of reduction burns around settlements; but we believe that remoter areas need a different approach.

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Canopy scorch

We see this as extremely damaging and possibly fatal to trees. This doesn’t appear to be the view of fire managers. At the very least, we believe canopy scorch makes trees vulnerable to other threats—like strong wind.

Destruction of big trees

Many substantial trees were brought down in the Hunters track burn: some were felled deliberately for safety reasons, others came down through fire damage.

It is not normally Department policy to destroy big trees, and when it happens, clearly something could have been done better. When we pointed out the large trees deliberately felled,  officers  explained that this was done to avoid injury to workers analysing the area after the fire. Obviously we appreciate this point. It was conceded, however, that their method of assessing ‘unsafe’ trees could be improved, however.

Trees brought down by the fire are another matter. A Gippsland Hawkeye research program found that Hollow bearing trees are 22 times more likely to fall down in fuel reduction zones than they are in unburnt areas, and this doesn’t surprise any of us who have prowled around these areas. The Department’s response has been to try raking around big trees, but this seems to be both random and ineffective.

Fire and forest health

It appears to be the Department view that fire is essential to the regeneration of this type of forest. Although we agree that fire has a role to play in the local ecology we differ as to how widespread and frequent the burning has to be.

We were challenged at the meeting to show any area of the Fryers Forest which had been damaged by FFMV’s repeated burns. The problem here is that  our knowledge is largely anecdotal, and it should be admitted that we see what we’re inclined to see. What we need is some baseline information on very long unburned bush, along with detailed records of how the local bush has or has not changed over the time of burning regimes. We do know, however, that bird populations are in long term decline, and that fire is one factor in that decline; and our own anecdotal evidence would suggest that Department fires have caused significant damage in some local areas.

We have been offered access to Department records, and we hope these will be enlightening. Unfortunately the current fires have stalled this process, but we’re hopeful.

However, in the shorter term: a comparison between the Maldon railway reserve [or any such reserve] and the adjacent forest would suggest that regular management intervention does have a quite dramatic effect in reducing biodiversity.

Further, we have been frustrated by the lack of reliable detailed knowledge about the effect of management action. We aren’t alone. Here’s the Auditor General in 2021:

‘DELWP cannot demonstrate if, or how well, it is halting further decline in Victoria’s threatened species populations.’

And

‘DELWP advised us that it cannot guarantee the protection of all threatened species given:

• current funding levels
• scientific constraints around how species respond to threats and actions to control these in the wild, particularly in a time of climate change
• the long-term lag effects on Victoria’s biodiversity of over 200 years of colonisation.’

Safety versus the environment?

A characteristic of these discussions is the repetition of the FFMV mantra: ‘public safety is the number one priority; environmental matters are number two.’ We accept this in areas directly adjacent to settlement; we don’t think it should apply in remoter areas. Or do we have to accept that all areas in our region are dangerous to the public? We are also wary of the consequences of such a prioritisation: too often it seems to us to mean: environmental concerns are set aside completely. As we tried to make clear in the meeting, we believe community safety and forest health are inseparable priorities.

Zoning questions

The Department has extensive ‘burn exclusion zones’: we should enlighten ourselves as to their relevance in the Fire Protection system, and how much light their condition would throw on adjacent areas. We have been offered the ‘possibility of a presentation from the Strategic Team’. We will follow that up.

The size of Department  burns

We’ve repeatedly said that we’d be a lot happier with the current system if burns were smaller in area. Some fire officers on the contrary, prefer larger burns, because more area could be covered by the system in the limited time window managers have. That seems to sum up many of the differences we have. 

And, of course…

This matter is not just a problem between conservationists and fire managers. It is a matter of general community concern, and decisions about it are ultimately political ones. In other words:  This is a political matter. The major political parties, the ones which get the votes, are agreed about burning the bush, differing possibly in minor details. We can have as many discussions as we like with the officers. They’ll still go away and follow the politicians’ instructions.