The Canadians and Yanks use two different approaches. They use large aircraft to fight fires as they occur from lightning strikes etc and smaller aircraft and helicopters when they get close to civilisation.They also use smoke jumpers in the wilderness, backing them up with the large bombers.
Unlike our approach they don't wait until a fire gets close to civilisation.
Up until recently they used a mix of large aircraft until one company lost a Liberator and an A model Herc, pulling the wings of both. Then followed a grounding of most large aircraft and an enquiry and the closing down of a few of the fire bombing concerns.
The Herc operations were a mix of contractors and Air National Guard. The ANG have developed a roll on/off Kit for a standard Herc. The privateers, or some at least, appear to have been involved in some interesting activities in their downtime. Others now operate Orions and L188s.Conair of Canada operate Firecats (Trackers) and CV580s and one Canadian company, Airspray operates L188 Longliners including former QF VH ECC. There are also DC6s and DC4s.The Canadians and a number of European operators use Canadair derivatives and a few Catalinas are still around but most now grounded.
The aircraft in Australia a few years ago was from memory a DC6 from Conair.Depending on how you look at it fortunately or unfortunately there was very little activity for it the year that it was here. I am not sure what a single aircraft would do anyway as the operation depends on a rapid strike by multiple aircraft to knock down the fire.
I have been told that the heavy approach is no good with our trees but California and most Med Countries are full of Gums and it seems to work there.
If you can think back to the video of the recent Helios B737 crash in Greece there were Canadairs busy in the background putting out the fire that the crash had started
I can't see under the current emergency requirents why say Airspray could not be contracted to bring out their L188s for the season. They should have no trouble with delivery range. Talking to some of the fire heavies a few years ago I came to the conclusion that the real problem was one of control and budgets. The only way to fund such an operation is via the Feds who could allocate across Australia. This puts the operations outside of the State Fire services. It also limits expenditure on other things like trucks etc.