Treated pine is simply not a compatible material in a Bushfire Prone Area, and I would suggest not putting it into the landscape, and to progressively phase it out of use on your property.

The CCA treatment that makes the pine resistant to rot and termites when used against earth, that process makes it even more readily ignitable and more likely to burn to completion than the pine that it started out as.

Well over 70% of the metal salt treatments that actually went into preserving that wood actually remain in the landscape as a green ash made up of toxic metal salts that ends up getting washed into the soil and is very bio persistent. So, it has toxic effects well after the fire, and is a particular risk for people attempting to clean up that area or to fossick through the wreckage.