U.S. Forest Service officials say the number of trees in Sierra Nevada forests killed by drought and bark beetles now is in the millions. And Nevada forestry’s Natural Resources Manager says the damage is starting to show on this side of the Sierra as well. “All you’ve got to do is stand back and take a look up the hillside,” said John Christopherson. “You see dead trees and dying trees.” According to the forest service, an estimated 66 million trees have died over the past half-dozen years in California’s southern Sierra.