SAN FRANCISCO (KPIX 5) — Head into California’s Sierra foothills and you might think the colorful views are seasonal. But what may look like attractive fall foliage is actually evidence of an ugly reality.

“It’s not like the fall colors that you have on the east coast. These are trees that are dying, and trees that are dead,” explained Sheri Smith, an entomologist with the U.S. Forest Service. Smith and her team are deep in the Stanislaus National Forest, on the trail of a killer no larger than a grain of rice.

“For native bark beetles in California, drought is the trigger. You can see some of the tunneling,” says Smith, pointing to the damage beetles have done to a sugar pine, lethally gutted by the infestation. It’s not just in the Sierra foothills. The beetles are clear-cutting their way through pine forest, all the way down to southern California.

“This is the worst spot in Kern County. This subdivision right here, we had trees that look like they were hit with shotguns,” said Jeff Glente, a forester for the Kern County Fire Department. Unfortunately, the state’s tree problems don’t end with bark beetles.

“In 2008 when I was in this exact location, you couldn’t see any sky,” said Yana Valachovic, a forest advisor for the University of California. She has been watching a disease called sudden oak death (Phytophthora ramorum) spread from Monterey County, through the Bay Area, and right on up the state’s north coast.

From the tips of the leaves, infected oaks turn brown – and then a ghostly gray – before falling to the forest floor. There’s really no stopping the disease in a forest so overgrown. While the disease delivers the fatal blow, Valachovic also blames an overpopulated forest.

Beetles, disease, too much density on the forest floor, any one of these things can be a problem for a tree or a forest. But when they happen together, fueled by four years of drought, problems mount into a full-scale tree disaster, one that now covers a large swath of California.

“We have estimated about 66 million statewide,” said Smith, giving the Forest Service’s latest tally of dead trees scattered across California. The worst of it comes from the bark beetle explosion along the Sierra foothills where aerial surveys have found thousands of acres where every single pine tree has died.

That’s what has unfolded in parts of Kern County, where Jeff Glente is trying to keep the dead trees from causing another disaster in the form of an explosive fire. That means homeowners are responsible for bringing those trees down, just as their property values fall right along with them.

“So it’s a real problem,” said Glente, “just getting rid of the trees without going broke doing it.”

There is likely an even larger price tag coming for all Californians as utility companies and Caltrans race to keep dead trees off of power lines and roadways.

As for the future – even some drought relief might make some problems worse. While a healthy rain season would slow the beetles, sudden oak death thrives in moisture, meaning normal rainfall could kick the disease into high gear.

“It’s really sitting here waiting for those right conditions, and it will have explosive growth again,” said Valachovic. She stressed that while the north coast die-off isn’t as spectacular as the Sierra mortality, more dead trees are inevitable.

It’s statewide catastrophe that has only intensified the debate over how California’s forest strategy should evolve – but for tens of millions of trees, the damage is done and recovery will take decades. For other areas, the worst may still lie ahead as California tries to untangle a crisis now unfolding across 32 million acres of forestland.

“We keep passing the buck,” lamented Valachovic, looking across a landscape of dead and dying trees, “not managing our fuels, not managing our resources, it gets harder and harder to solve the problem.”