Use of prescribed burns in areas prone to wildfire has fallen since 2011, according to a study by advocates of the practice.

A total of 11.3 million acres were treated with fire in 2017, down 12 percent from the 12.8 million acres treated in 2011, the Coalition of Prescribed Fire Councils and the National Association of State Foresters reported today.

The groups attributed the decline to several factors, including weather, access to wilderness, politics, liability and cost. Regardless of the reasons, they said, the report suggests officials should examine the impediments to prescribed burns, which the organizations consider a vital part of managing many forests and prairies.