"Essentially it's choking the tree off," Glen Miller of the California Department of Forestry and Fire Protection told CBS News Correspondent Sandra Hughes.
The bark beetle is choking so many trees, normally green forests look like they've been painted brown. And thousands of mountain homes are in the line of fire.
Bob White watched 16 of his trees die virtually overnight. He showed Hughes his now-denuded back yard.
"This is the backyard. Sixteen of 'em, sixteen beautiful trees,'' he sighed.
How did it get this bad?
A century of fighting fires instead of letting Mother Nature clear the forest, then four years of devastating drought. That's left an overstocked and vulnerable forest and it's a recipe for disaster.
Asked what's his biggest fear for this summer, Gene Zimmerman of the U.S. Forest Service replied, "Catastrophic fire, without a doubt. The possibility of a fire where we could lose an ecosystem, lose communities and lose a lot of lives."
Normally, healthy trees can push a predator beetle out of its bark, ensnaring it in sap. But the drought-weakened trees don't even try. Fighting the tiny tree eater seems impossible.
"We work fourteen days straight, ten hours, ten-twelve hours a day," said tree remover Jim Miller. "There's not enough qualified people to cut all these trees."
And once the trees are gone, it will take a lifetime to grow them back - too long for Bob White.
"We raised our children here, played in this back lot, climbed the trees. Of course those are all memories now," he said.
He can only hope by cutting down his trees, he's saving his home from fire.