GEORGETOWN, California — Waves of fire swept through the Sierra Nevada forest under the watchful eye of a heavy-duty drone. …Prescribed burns, an age-old practice that rids forests of the small trees, brush and other matter than can fuel wildfires, are getting a 21st-century upgrade. With climate change parching the land and increasing wildfire hazards, scientists are beginning to use cutting-edge technology and computer modeling to make controlled, low-intensity burns safer, more effective and less disruptive to nearby communities. …While researchers have long deployed advanced techniques to examine wildfire behavior, fewer have looked at questions specific to prescribed fires, like whether debris should be cleared away with chain saws and bulldozers in advance, said Robert York, a forest ecologist with the University of California, Berkeley. …Better fire modeling is important, but so is baking that knowledge into easy-to-use tools for burn crews. [the access the full story a NY Times subscription is required]