The tranquility of Annadel State Park's forested hillsides will be pierced next week by the shriek of chainsaws felling dead trees throughout the 5,000-acre preserve.
CalFire crews will begin toppling about 2,000 Douglas fir trees that have been killed over the years in an effort to keep them from overrunning the native oak woodlands.
The slopes of the park are marked with such towering snags. Their lifeless limbs stand in ghostly grey contrast to the green canopies of the park's much older oaks.
They're an eyesore to some park visitors and felling them will improve the aesthetics of the park, said Gerald O'Reilly, maintenance chief for the Marin/Diablo Vista state parks district.
"At this point it's basically a clean-up project," he said.
Taking them down now also will reduce future maintenance, he said. The trees were "girdled" -#8212; cut with a chainsaw around the base a few inches into the sapwood -#8212; more than a decade ago to keep them from shading out the shorter oaks. Biologists expected them to rot and fall over on their own, but many of the sturdy trees have remained defiantly upright.
"That part didn't go quite as planned," O'Reilly said.
When they do fall on their own, the trees can block trails and roads, forcing park maintenance crews to remove them. Cutting them now will reduce that future workload, O'Reilly said. The work also will give CalFire crews an important training opportunity, he said.
The trees won't be removed or harvested for lumber but will be left on the ground to rot, O'Reilly said. Removing them would require the use of heavy machinery that would do more harm than good, he said.
"Skidding logs out of the forest was going to do a lot of damage to what we were trying to protect," he said.
What they're trying to protect is one of the best examples of native oak woodland in the state. Studies have shown that the suppression of wildfires in Annadel has allowed the faster-growing fir trees to invade the oaks' territory.
Historically, fires regularly swept through area, clearing out the young fir trees but leaving the mature Oregon oaks to bask in full sun. Without those fires, the fast-growing firs had begun to shade out the oaks, killing them.
Over the years, state parks biologists have used controlled burns, girdling of mature fir trees and regular removal of smaller fir trees to keep them at bay.
The effort has been controversial. Some have questioned the wisdom of killing one type of tree to preserve another. Controlled burns in a park surrounded by homes have raised air quality concerns. And fire officials have warned that so many dead trees might increase the risk and intensity of wildfires.
Parks officials say the program actually has decreased the amount of fuel for wildfires in the park and has succeeded in preserving the oak woodland and the biodiversity it sustains.
While he understands the reasoning for killing the firs, Ken Wells has always been troubled by the visual impact of the effort. He is executive director of the Sonoma County Trails Council, a group whose volunteers work to maintain the park's trails for hikers, mountain bikers and horse riders.