This article relates to the ongoing debate on Australian Rural & Regional News into Bushfires, Logging, Burns & Forest Management

Roger Underwood

I have recently re-read Think Trees, Grow Trees, a 1985 publication from the Institute of Foresters of Australia. This excellent little book was the brainchild of, and was edited by Dr Wilf Crane, one of my contemporaries at the Australian Forestry School, a notable forest scientist and famous and eccentric character.

Wilf was motivated to publish the book by his concern about the decline of trees and woodlands on farmland in eastern Australia. His aim was to encourage professional tree planting (the right tree in the right place), but also professional management of trees, woodlands and forests to ensure their health, vigour, productivity and long life.

To me, the most important part of the book (in terms of contemporary relevance) is the chapter called Living with Fire. It is written by Phil Cheney. Phil was also a friend at Forestry School. He later became the chief of bushfire research in the CSIRO, Australia’s premier bushfire scientist and expert and was the recipient of international awards for his research into fire science.

I read Phil’s chapter with interest, but also (ultimately) with falling spirits. The paper (written over 40 years ago now) is full of bushfire wisdom, basic bushfire science and the sort of practical common sense that is underpinned by real-world experience – exactly what every Australian bushfire manager became accustomed to read from Phil back in the day. What depressed me, however, was the realisation that the wheel has turned since it was written decades ago, and key lessons have been forgotten. Out in today’s bushfire world, especially in Victoria and NSW, but to a lesser extent Qld and Tasmania, the same old errors that Phil cautions against are still being made, the same traps fallen into, and there is the same failure to profit from the lessons of  bushfire history and science. The paper begins with a statement so sound and so basic, that almost nothing more needs to be said:

In the Australian environment, people who chose to live in the country or in the bushland surrounding our major cities, must accept that fire is an integral part of that environment. They must understand how fires behave, and what measures can be taken to minimise the impact of wildfires under extreme conditions.

If only they did. On the contrary, from what I can see around the country, very few people who live in bushfire-prone areas are aware of the dangers, or appreciate the threat … at least not to the degree that they are motivated to take the necessary mitigatory measures. Nor do our government agencies achieve much success in either educating them, or enforcing responsible bushfire preparedness. In Western Australia, for example, where things are mostly better than in the eastern states,  I can still name two major country towns (Denmark and Margaret River) where the community is mostly in a state of denial about the bushfire threat, while at the same time local environmentalists are active in opposing appropriate mitigation (like fuel reduction burning).

Phil Cheney did not mince his words. “Conflagration fires” (his term for the high-intensity, uncontrollable fires that cause serious damage), he wrote, will always occur whenever the following elements occur simultaneously: heavy and continuous fuels, drought, strong hot winds, and an ignition source. This is a precise description of the situation that prevailed in the lead-up to the Black Summer bushfire disasters in 2019/20. Amazingly, the conflagrations that summer caught the community by surprise. The local ‘Fire Chiefs’, who should have been aware of Cheney’s prescription for bushfire calamity, and well-prepared for the calamity, blamed the fires on “climate change”.

Living with Fire was written well before the notion that climate-change-causes-bushfires had become accepted wisdom. Nevertheless, Cheney anticipated the ‘Fire Chiefs’ in a section of his paper about fire behaviour. On the subject of temperature, he says:

People naturally tend to relax fire precautions on cold days – but if low humidities are forecast [you need to remember that] … fires burn almost as fiercely on cold dry days as when the temperature is high.

This is a point which the ‘Fire Chiefs’ deny, and most journalists misunderstand. About once or twice every summer I am telephoned by some journalist after a hot day has been forecast and asked for a doomsday comment. Over and again, I point out that temperature per se is not the factor that firefighters fear: it is the combination of strong winds and dry fuels (low humidity) that ensure things will be difficult on the fire front. Indeed, as Cheney points out “a fire burning under calm conditions is relatively easy to control, even if the fuel is heavy and the fuel moisture content is very low.” The alternative scenario was demonstrated dramatically in the February 2021 Wooroloo Fire in WA. The temperature was relatively mild, but strong winds combined with a low dew point, and heavy, dry fuels, led to an intense and fast-moving fire that defied all initial efforts at control.

The idea that fires will become uncontrollable if global temperatures rise a couple of degrees flies in the face of long bushfire experience, to say nothing of elementary physics.

Back in 1985, Cheney also anticipated the latest fad among environmentalists opposed to bushfire-mitigation burning. This is the notion, advanced by academics like Professor Zylstra of Curtin University, that if eucalypt forests are left unburnt long enough, they will become non-flammable. This absurdity is extrapolated by the anti-burning brigade to assert that therefore bushfire-mitigation burning is not needed. However, as Cheney pointed out, based on his own experience and that of hundreds of foresters and firefighters all over Australia over the decades:

… forest fuels … continue to build up until the rate of decay more or less balances the rate of litter fall. In an unburned mature forest, fuel loads of 15-20 t/ha are common. Under drought conditions, large logs and deep, partially decomposed litter beds dry out and are consumed by a fire. More than 50 t/ha of surface fuels may be burned by a forest fire during a drought. This … is the reason why forest fires are so damaging and so difficult to control under drought conditions.

Cheney does not fail to point out the other critical factor relating to long-unburnt forests, especially those comprising mostly stringybark trees. This is the way, in the long absence of fire, fibrous bark accumulates on the tree stems. When ignited in a wildfire the bark becomes the firebrands that start spot fires down-wind, or the embers that flow into and ignite houses. One of his many sensible recommendations to people living in fire-prone areas is to replace stringybark trees with smooth-barked species in the surrounds of the home. The green bureaucrats in the City of Armadale in WA have none of this. On the contrary, as part of their Urban Forest Strategy, they urge land owners in the bushfire-prone area of the Perth Hills to plant up their back and front yards with jarrah trees, i.e., stringybarks of extreme flammability.

As expected, Phil Cheney is a strong advocate of people being responsible for their own bushfire safety, and for taking appropriate measures to protect their own properties.

Ask yourself this question? [he asks an imaginary land owner]. Why should a volunteer firefighter put his life at risk to protect your property when you are not prepared to institute a few basic hazard reduction measures? Remember, they are volunteers.

He also makes another very pertinent point, seemingly forgotten so often by firefighting agencies these days:

In a major fire, firefighters must concentrate on suppressing the fire rather than saving individual homes. Sounds tough? Maybe, but there are many examples where fires might have been contained to a few hectares if the firefighters had concentrated on suppressing the fire rather than on protecting a home with hazardous surroundings.

This was one of the most important principles I was taught as a young firefighter. The first priority must be to attack and put out the fire. The alternative approach of focusing on “saving assets” while letting the fire burn unchecked is advocated by many “Fire Chiefs”. Thus, fire crews operating in the face of the approaching headfire are sent from home to home to home, heroically trying to save them, winning some, losing some, while the fire just gets bigger and nastier, and descends on ever more homes. Trying to save assets instead of stopping the fire is a hopeless strategy; firefighters are constantly being put in the most dangerous situations, and end up chasing their tails, never getting in front of the game, and ultimately dependant for relief only upon the arrival of rain.

Needless to say, one of the main reasons why the assets take so much effort to save and often cannot be saved, is because they are so ill-prepared, the land-owner having taken no responsibility for making his land and house as resilient to fire as possible.

There is one final lesson from Phil Cheney’s paper: bushfires, he wrote, must be attacked and if possible extinguished as soon as possible after detection. You would think this hardly needs to be said. But again, I have observed a surprising new approach emerge (first seen, I think, in the 2003 Canberra fires). This is the policy of watch and wait, allowing a bushfire to burn along happily by itself, during which time the authorities “keep an eye on it” but take no steps to control it. When I read about a fire in a national park in NSW during the build-up to the 2019/20 fires being allowed to burn unchecked for three weeks, I nearly fell off my chair. Yes, it didn’t do much during most of that time, other than grow in perimeter. But as soon as angry weather conditions arose, it got up, and then it got away. “Watch and wait” is possibly the most retrograde policy change in Australian bushfire management, equal in stupidity only by the incomprehensible “Residual Risk” approach adopted by the Victorian government.

Coming across, and reading Phil Cheney’s 1985 paper in Think Trees Grow Trees was almost nostalgic … a bit like an unexpected meeting with old friends on a social occasion. Here were the golden bushfire principles, and the practical nous that I had been brought up on, and which once guided Australia to a pretty good position in the bushfire world. But much of it seems to have been forgotten or is being undermined by “experts” from academia and “Fire Chiefs” with a bee in their bonnet about global warming.

Best of all, I was reminded that Phil was one of those old-fashioned bushfire scientists. He worked in the field with real fires, and he established a sound working relationship with real bushfire managers, foresters and brigades. I compare this with the “bushfire experts” of today, especially those in academia, who work entirely from the comfort of their office in a leafy campus, playing with computer models, and far-removed from the smoke and heat of actual fires. I am very happy that Phil is not yet in his grave, because if he was, he would be turning in it when he observes the way bushfire management and research has gone in Australia over the last 25 years.

Reference:

Department of Arts, Heritage and Environment in association with the Institute of Foresters of Australia (1985): Think Trees Grow Trees. Australian Government Publishing Service, Canberra.

Roger Underwood is a member of The Bushfire Front of WA Inc.