Controlled burns remain essential as US wildfires intensify

In 2015, the Lake Fire burned 31,000 acres in this popular hiking forest northeast of Los Angeles. It destroyed four buildings, came perilously close to the resort town of Big Bear Lake and took more than 1,900 firefighters five days to contain at a cost of almost $40 million.

This is why it seemed counterintuitive to see some of those same firefighters walking along the forest floor in April with red drip torches,…