There have been controlled burns:
$1:
How much hazard reduction has happened?
In the last full fire season of 2018 and 2019, the National Parks and Wildlife Service in NSW told Guardian Australia it carried out hazard reduction activities across more than 139,000 hectares, slightly above its target.
There are two major restricting factors for carrying out prescribed burning. One is the availability of funds and personnel, and the second is the availability of weather windows.
The 2018-19 annual report of the NSW Rural Fire Service says: “The ability of the NSW RFS and partner agencies to complete hazard reduction activities is highly weather dependent, with limited windows of opportunity. Prolonged drought conditions in 2018-19 adversely affected the ability of agencies to complete hazard reduction works.”
The RFS said 113,130 properties had been subject to hazard reduction activities, which was 76% of its target. The 199,248ha covered was 106% of its target.
https://www.theguardian.com/australia-news/2020/jan/05/explainer-how-effective-is-bushfire-hazard-reduction-on-australias-firesWhat mitigates them is the fact the seasonal window for doing burns is getting shorter thanks to climate change and the fact that the Aussie government reduced funding for land management in recent years.
Also, the fires this year have been so intense that land that had previously been burned by controlled and uncontrolled burns, burned again weeks after the fact.