Trees and wildfire - damaging mythology, just plain ignorance or self-serving risk avoidance

On commencing this blog on 16 February 2014 my intention was to assist people having difficulty with the Bushfire Management Overlay (BMO) considering the frustration I was encountering from the CFA and some councils in representing some of my clients and well aware that there were and continue to be others in the community experiencing similar difficulties.

The basis of dealing with the BMO as part of a planning permit application should be understanding fire behaviour, lacking in much of the community, and seemingly in part of corporate CFA when it comes to dealing with BMO referrals.

CFA promulgates its attitude toward the BMO at this time in a one-size-fits-all set of bushfire protection conditions, regardless of the actual conditions that contribute to fire behavior likely to affect a dwelling the subject of a specific planning permit application.

This attitude seems to be premised on a statement on the first page, penultimate paragraph, second sentence of the standard planning permit conditions: "Any justification for a tailored response should be included in the application". Why, who makes the decision and on what basis? More about this attitude later, but back to trees and wildfire now.

In the standard planning permit conditions there is a one-size-fits-all requirement under the heading Defendable Space stating that "the canopy of trees must be separated by at least 5 metres".

An arbitrary five metres canopy separation usually generates a planning permit condition requiring offsets that can be very costly to someone trying to establish a new home — many thousands of dollars, approximately $120,000 in one situation I'm aware of. Imagine the impact of that extra cost on a young couple trying to establish their dream home.

Raises the question, why would the CFA require a blanket canopy separation, is it because canopy or crown fire is not well understood by some CFA people making policy and dealing with BMO referrals? Hopefully the following will help.

Some examples to get the subject started.

In a blog posting on 23 April 2016 I included the following photographs from Wye River in the aftermath of the Christmas Day fire where crown fire was virtually non-existent. Observe the unburnt vegetation virtually to ground level.

And, what better than some examples from Ash Wednesday 1983. The following are from my collection photographed in the Lerderderg State Park a few days after the Trentham East fire. They show the effect of the fire at the time it was still heading in a generally southeasterly direction towards Bacchus Marsh and prior to the wind change to the southwest much later in the day forcing it towards Mount Macedon.

Above is a view of Firth Park in the Lerderderg State Park showing an absence of crown fire in the forest in the background. Note the singed trees or shrubs in the foreground.

The following two photographs are further south from Firth Park towards Bacchus Marsh.

What is particularly significant about these two apart from the lack of crown fire? Observe the unburnt shrubs/suckers at the base of the trees!

Below from my blog posting of 22 June 2014 are two examples of trees and shrubs in the path of the 9 February 2014 Gisborne fire as it travelled northeast towards Riddells Creek after the wind change.

The fire weather conditions this day were described as being the worst since 7 February 2009 (Black Saturday). Again, observe the vegetation close to the ground left unburnt when the fast moving grass fire passed.

The evidence is that crown fire is a relatively rare occurrence.

To quote Professor Julius Sumner Miller, "Why is it so?" The answer is in the fire triangle.

I will continue this theme in my next posting. Meantime, those of you who have or are still grappling with the BMO as part of a planning permit application may find the BMO Amendment VC109 July 2014 Explanatory Report of interest — ninth dot point on page 2 "remove their veto power" read the "CFA". It does not seem to be working in the manner then Planning Minister Guy intended, or maybe it is?

People grieving over the loss of trees in Wye River-Separation Creek may also find this posting of interest and it raise some questions.