A forest-thinning bill authored by Northstate Assemblyman Brian Dahle and signed into law in 2013 has been extended. The original bill expanded on the 2003 Fire Prevention Exemption Act. Designed to eliminate the horizontal continuity of tree crowns and the vertical continuity of vegetative fuels, the law allowed landowners to cut down trees up to 18 inches in diameter without filing a timber harvest plan. The 2013 amendment expanded that to include trees up to 24 inches in diameter, measured 8 inches above ground level. The expansion was a 3-year pilot program, and that 3 years is up, so a new law had to be passed to extend it. The program is restricted to the boundaries of the Sierra Nevada Conservancy, as well as areas designated by Cal-Fire as having moderate, high, or very high fire danger. The bill was supported by the timber industry and opposed by environmental groups.