Roughly 500 years ago in California’s High Sierra, pine cones dropped to the ground and a cycle began. …Half a millennia later, US Forest Service scientists began testing strategies to save these now ancient and massive trees in the little-known area east of Fresno called the Teakettle Experimental Forest. They had plans to light a huge prescribed burn to clear overgrowth next year.  But then the Garnet Fire ignited and scorched all 3,000 federally protected acres on its path through the Sierra National Forest. …Scott Scherbinski, a biologist at the Climate & Wildfire Institute, said “It will be a start-over event for this forest.” …Malcolm North, a Forest Service ecologist said…fires with less intensity can be beneficial in California’s fire-adapted landscapes, but the Garnet Fire, when it burned through in September, may have killed most trees and sterilized the ground — making it unlikely the forest can rebound without intervention. [to access the full story a San Francisco Chronicle subscription is required]