Australia The Department of Parks and Wildlifes annual report reveals the average area subject to controlled burns in the South West has fallen more than 70 per cent over the past five decades.
But over the same period the total area ravaged by wildfires rocketed as blazes were made worse by increasing fuel loads and a warming, drying climate.
The figures show the mean area burnt by prescribed fires has fallen over the past 50 years from about 350,000ha a year in the 1960s to just 100,000ha a year so far this decade.
Uncontrolled bushfires have burnt 75,000ha a year from 2010 to June this year, compared with just a few thousands hectares a year in the 1970s.
The department burnt 154,000ha across the South West in 2015-16, its best result in six years, but still short of its target of 200,000ha a year. In a new breakdown of the result, it said it had achieved 61 per cent of its separate targets for areas closer to population centres.
Factors contributing to the decline in prescribed burning include population growth leading to more fragmentation of the landscape and more urban development in proximity to bushland, the report said.
This is coupled with a gradual change in departmental firefighting resources (as reflected in the reduction of employees engaged in frontline fire management from 530 in the mid-1980s to 290 in 2015), a drying south-west climate and the escalating cost of prescribed burning under more stringent and necessary risk management arrangements.
The figures come following a horror year of bushfires in southern WA including the fatal blazes in Esperance in November and Yarloop in January.
Of the 720 bushfires across the State that DPAW monitored during 2015-16, lightning started 32 per cent, above the 10-year average of 24 per cent.
Fires deliberately lit or sparked by arsonists accounted for 37 per cent of monitored fires, down from a 10-year average of about 41 per cent.