The staccato beat of a yellow and blue helicopter’s rotating blades drowned out nearly all other noise as the pilot Joe Ryan tilted the aircraft from side to side and made low circles over power lines west of Ukiah.
It was a clear morning and Ryan and two foresters on board the aircraft were scouring the area for dead and dying trees that could topple into Pacific Gas & Electric transmission lines, triggering outages and potentially igniting fires.
“I think we’ve got a dead one here,” Ryan said into a microphone, relaying instructions to Amy Rowe and Chelsea Michael, foresters with Western Environmental Consultants Inc.
The team, including Ryan of A&P Helicopters, has been hired by PG&E to survey its lines across several North Coast counties, where the state’s prolonged drought, insect infestation and disease have all taken a heavy toll on forests.
Though abundant rainfall this winter banished the drought, the dangers presented by the state’s ravaged forests are higher than ever, according to utility officials, firefighters and foresters. Statewide, an estimated 102 million trees have died during the drought and its immediate aftermath, with many millions more expected to succumb in the next few years.
“No amount of water was going to bring back those trees,” said Heather Williams, a spokeswoman for Cal Fire, the state forestry and firefighting agency.
As a result, PG&E, which annually inspects all 134,000 miles of its overhead power lines in northern and central California, last year added a second patrol on some 68,000 miles of line located in high fire hazard areas, said company spokeswoman Linsey Paulo. This year, it plans to patrol 73,000 miles of line a second time.
The hot spot for dead trees in California remains the Sierra Nevada range, where vast swaths of red and brown trees cover mountain sides. Some 76 million trees have died in the ten worst hit counties, including Amador, Calaveras, El Dorado, Fresno, Kern, Madera, Mariposa, Placer, Tulare and Tuolumne, according to the state’s Tree Mortality Task Force, which includes local, state and federal agencies and utility companies such as PG&E. The tree mortality data is based on the U.S. Forest Service’s annual aerial detection surveys.
While not among the hardest hit, Northern California counties also have seen spikes in tree mortality.
Forest Service survey maps show the highest concentrations of dead trees in Mendocino and Lake counties are in the Mendocino National Forest. Sonoma County has several concentrated pockets of dead trees just west of Cazadero and south of Lake Sonoma, according to state data.
In fire prone Lake County, the Boggs Mountain Demonstration State Forest is among the prime problem areas. It was hit by a beetle infestation before the Valley fire swept through in late 2015, turning the forest into a graveyard of blackened firs and pines. Trees in the area that were not burned remain under attack by the pests. Water-starved conifers are more susceptible to pests and diseases because they are unable to produce sufficient sap to ward off the invaders.
The wave of tree deaths has not been as intense in Mendocino County, but it’s still taken a toll, with some 330,000 dead trees recorded during Forest Service aerial surveys since 2010, according to Cal Fire. The highest count was in 2015, with 133,000 trees.
PG&E, which normally prunes or removes some 1.2 million trees annually, removed an extra 236,000 dead and dying trees from its right of ways statewide in 2016, Paulo said.
Of those, about 6,200 were in Mendocino County, she said. This year, the company expects to remove or trim 200,000 trees statewide, including 3,200 in Mendocino County and 800 in Sonoma County.
“It’s a critical need out there,” Paulo said.
Other agencies, including Cal Fire, the U.S. Forest Service and Caltrans also are working on removing dead trees and brush to reduce fire hazards.
From the air, the local surveys for PG&E start with Rowe noting a dead or dying tree. Michael then clicks the button on her GPS device, pinpointing the spot and jots the information on a pad of paper. Later, ground crews — after notifying the landowner — will examine the tree up close to decide whether it should be cut or trimmed.
Needles from dead trees add extra fuel for fires in areas already at risk from the bumper crop of grasses and brush generated by heavy winter and spring rains.
“We’re anticipating that it’s going to be a very busy fire season,” Williams said.
In Mendocino and Sonoma counties, many of the tree deaths have only partial ties to the drought.
Sonoma County’s predominant problem is with sudden oak death syndrome, which actually was deterred by the drought because its pathogen is a water-loving mold. The rain is expected to bring a new surge of the disease, said Greg Giusti, a forest specialist with the UC Cooperative Extension.
On the Mendocino Coast, bishop pines also are dying in large numbers, he said. The cause is a combination of old age — they’re 80 to 90 years old and at the end of their lives — beetles and fire suppression, Giusti said.
Bishop pine require fire to open their seed-bearing cones, he said. Prescribed burning might help, but too many people now live in wooded coastal zones, so it’s unlikely that will happen on a large scale. The trees also have been attacked by beetles, many generated by Monterey pine, a shorter-lived, introduced species.
“PG&E is worried about these trees,” Giusti said, noting bishop pine can grow to 90 feet tall and could easily fall into power lines when they die.
Between Boonville and Ukiah this week, the dead trees spotted by the PG&E crew included a variety of pine, fir and oak trees.
“Chelsea, we have a pine here that looks pretty bad,” Rowe said.
“Got it,” Michael said.
You can reach Staff Writer Glenda Anderson at 707-462-6473 or firstname.lastname@example.org. On Twitter @MendoReporter.