Phil Cheney (1)

This is a fairly technical book but one that I found quite fascinating. Having just finished reading it, the section on myths about grassfire is probably uppermost in my mind. And it is a myth that if you jump into a tank of water that you will be boiled alive. The passage of a grassfire is unlikely to raise the temperature of a water tank by even a fraction of 1 degree C. But you need to protect your airways from hot gases and ash.
I think the book does the job that they set out to do; to make the science available and understandable to the ordinary person.
I did learn that most fires are only going to move at about 20 km per hour ...though they will move considerably faster than this on an up-slope.
I did learn that forest fires have a lot more fuel and are hotter and harder to predict and extinguish than grassfires. And if you are in your car and trying to survive...you have a better chance in a paddock than in an area alongside a road where there are trees.
The authors have developed a number of slide rules or nomograms for predicting the rate of forward spread for grassfires ...and others for fire danger. I guess you don't have to be a genius to figure out that a combination of: higher temperatures, low fuel moisture content and wind is a pretty potent mix for fires.
I also found it interesting that the convection columns associated with fires or downdrafts associated with thunderclouds could radically change the wind direction for considerable distances (up to 6km).
By and large, the authors bring a good dose of common sense to working with fires. And hopefully, whilst not minimising the danger of fires to those caught up in them, they give sound advice about managing them. When it makes sense to try and suppress the head fire and when it doesn't make sense. And if you are going to try and suppress the fire on the flanks, in Eastern Australia you should do this on the eastern or north eastern flank because this is the one that is most likely to break away when the wind changes. The normal pattern of wind shift during the day is anti-clockwise.

The authors don't really (if at all) talk about climate change but clearly, climate change is going to mean more fires and more severe fires rather than less.
I found myself wondering about the possibility of ploughing fuel....especially from forests into the soil or otherwise removing it from the surface. this would increase the carbon content of our soils and reduce the fuel load in the forests. Could we use termites? ants? fungi? worms? Of course, it would be impossible in some terrain and the leaf litter shed during dry spells would soon replenish the fuel....but not by very much if the burying was done in systematic, wide firebreaks and repeated once in a while.
Quite an interesting and useful book. I give it five stars.… (mais)