Georgetown, CaliforniaRob York walks calmly through the quiet pines deep in California’s Sierra Nevada foothills, trailing a mix of kerosene and gas from a canister behind him onto the forest floor, which crackles alight into low flames.

“It’s nice, right?” he says to the group of locals gathered at the fire’s neatly contained edge, turning around to draw another delicate line of fire across the designated burn zone. 

To many Californians, fire signifies danger. But here, on a cool, serene day in the pines, controlled flames go only where York, a scientist and forester with the University of California’s Blodgett Experimental Forest, and his colleagues direct them.

He has been out in the trees for hours, checking the humidity and