PONDEROSA BASIN, Mariposa County — When Ursula Rowe returned to her mountain home after a hip replacement a few months back, the landscape had changed. Dozens of towering pine trees had browned up and died on her once-verdant plot of land near Yosemite, and she had to cough up $25,000 to remove them.

“I couldn’t see that house before,” said Rowe, pointing from her deck across 50 lifeless stumps to the properties of neighbors also littered by downed pines and piles of split wood. “I had to go out and buy blinds for my windows.”

California’s drought-driven epidemic of dead trees has ushered in a cascading crisis from the community of Ponderosa Basin in the central Sierra to towns closer to Lake Tahoe. As government agencies and private landowners race to clear trees that could supercharge wildfires, they’re ending up with a glut of wood that nobody knows what to do with.

Turnouts along rural highways are becoming way stations for timber, and counties are opening makeshift stacking yards. Often, fallen trees are simply left on the forest floor, sometimes closing trails and campgrounds, or they remain sprawled across people’s yards. Signs for “free firewood” have become as ubiquitous in many mountain areas as the buzz of chain saws.

“A lot of these trees are sitting alongside the road because there’s not a place for them to go,” said Len Nielson, the lead forester in Mariposa County for the California Department of Forestry and Fire Protection, or Cal Fire, as he made his rounds surveying tree-cutting efforts on a recent day.

While Nielson and others acknowledge that allowing downed wood to pile up is anything but ideal during fire season, it’s better than leaving vast stands of dead trees that could feed an inferno. Fire officials hope to eventually move the debris, but areas like Mariposa County — despite its lumberjack-themed tourist towns and shops with names like Lucky Logger — no longer support a timber trade to process the wood.

“We don’t have a logging industry anymore,” Nielson said, motioning from his truck toward an old sawmill that’s now just a lumber yard.

Tree triage

At least 66 million trees have died in California since 2010, more than a third within the past year, according to recent estimates by the U.S. Forest Service. The die-off is the result of five years of drought that has deprived forests of water and allowed bark beetles to take advantage of the trees’ weakened condition.

“We’re finding these trees are extremely dry, and they’re deteriorating much faster,” said Steve Brink, a vice president of the California Forestry Association.

State and federal forestry officials, alongside local governments and Pacific Gas and Electric Co., have launched a massive effort to remove trees closest to roads and communities where the fire threat is greatest. A couple of hundred thousand trees have already come down in what’s become a sprint to clear as much dry fuel as possible before the fire season peaks in late summer and early fall.

“Regardless of the mills or the market, we have to cut these trees or they’re a direct threat to life and property,” said Ken Pimlott, director of Cal Fire.

Debris loses value

Already, the smell of smoke is wafting through many parts of the Sierra. The Erskine Fire has charred nearly 50,000 acres and leveled 200 structures near Lake Isabella in Kern County, while the Trailside Fire is threatening more homes in Placer and El Dorado counties.

The largest stands of dead forest, most of which are ponderosa pine, are being cut down and trucked to some of the 25 mills that remain from California’s once-booming logging trade. Most of these facilities, though, are already inundated with salvaged wood from past wildfires.

Because much of the wood is rotted or stained blue from beetle infestation, most of its value is lost. It may become mulch or animal bedding. Power plants that use organic materials to generate electricity have also been receiving some of the lesser-value forest debris. But like the mills, there’s not a lot of them, and they have only so much capacity.

Heavy price

The expense of getting rid of the wood, meanwhile, is paralyzing communities. For property owners with dead trees, the best-case scenario is that they have a stand with enough healthy timber to cover the cost of removal. Taking down a tree can run hundreds, if not thousands, of dollars.

“I about fainted when I found out” the price, said Rowe, who used a combination of savings and borrowing to pay her $25,000 bill. “Heck, I could have gotten a new car.”

While many in Ponderosa Basin have paid to have their dead trees removed, one of Rowe’s next-door neighbors hasn’t done anything about a handful of expired pines that remain perilously close to Rowe’s property.

“He said that within a week or so he’ll get someone in,” she said.

Groups like Mariposa County’s Fire Safe Council and Resource Conservation District have helped many residents who can’t afford tree removal. PG&E has also downed thousands of trees near power lines. Cal Fire, the state Department of Transportation and county crews have helped clear private lands as well. But there’s not enough money to do all the work that’s needed.

The state has made $31.5 million available to counties under Gov. Jerry Brown’s declaration of an emergency last October caused by dying trees. Since the financing requires a 25 percent match, though, only so much has gotten done.

“When we’re talking about removing the number of hazardous trees that we have in our areas, we’re looking at millions of dollars,” said Mariposa County Supervisor Rosemarie Smallcombe. “Most counties don’t have that much money lying around.”

In places like Ponderosa Basin, as much as 90 percent of trees are dead. The county’s Office of Emergency Services estimates that 500,000 trees are a direct threat to people or property. Only about 23,000 have been removed.

“Until people come up here and drive around, it’s hard to wrap your head around this,” said Don Florence, a planner in the Office of Emergency Services. “You couldn’t have a worse standing hazard.”

Residents are keenly aware of the danger. Bill Harsh of Ponderosa Basin was happy to see PG&E drop 25 dying pine trees in his yard, though he knows there’s so much dead forest around the community that the removal efforts will only go so far.

“If we get a fire, they won’t stop it now,” he said. “We’re surrounded by dead trees. My goodness, we’ve never been surrounded by so many dead trees.”

As part of the governor’s emergency declaration, an unusual task force was created to figure out what to do with trees as they come down.

“We can’t keep stacking logs in the woods,” said Larry Swan, a woody biomass and utilization specialist for the U.S. Forest Service who is part of the new working group. “We have to think about fires and the safety of our firemen and women. ... This becomes an impediment to suppression.”

Shipped out, burned up

The governor has called for more bioenergy production, allowing additional woody debris to be disposed of at power plants. The task force is also looking into increasing wood exports — already some trees are being hauled to Oakland for shipment to China — as well as utilizing chips for dust abatement and soil enrichment at the giant Salton Sea in Southern California.

About $6 million in mobile equipment, paid for under the emergency order, has been rolled out by Cal Fire to process trees that aren’t likely to go anywhere. Chippers, sawmills and 10 air curtain burners — essentially wood incinerators — are among the new gear.

Even with these efforts, the volume of dead trees — estimated by the Forest Service to be 14.1 billion board feet — is 10 times the state’s annual timber harvest.

“We’re using every tool in our tool chest,” said Swan. “This is not a year or two issue. We have to take a look at it five or seven years out, at least.”

Kurtis Alexander is a San Francisco Chronicle staff writer. Email: kalexander@sfchronicle.com Twitter: @kurtisalexander