 Before the late 1960s, fires were generally believed to be detrimental for parks and forests, and management policies were aimed at suppressing fires as quickly as possible.However, as the beneficial ecological role of fire became better understood in the decades before 1988, a policy was adopted of allowing natural fires to burn under controlled conditions, which proved highly successful in reducing the area lost annually to wildfires.In contrast, in 1988, Yellowstone was overdue for a large fire, and, in the exceptionally dry summer, the many smaller "controlled" fires combined.