Black streaks run 40 feet up the trunks of a ring of redwoods in the Pepperwood Preserve off Porter Creek Road in the Mayacmas Mountains northeast of Santa Rosa.
The trees are healthy, silently bearing the scars of the epic wildfire of September 1964 that rattled Santa Rosa's nerves before it was stopped about 100 feet from the door of the old Community Hospital on Chanate Road.
Nearly all of the 3,200-acre preserve was scorched as 70 mph winds, close to hurricane strength, blasted the Hanly fire from Calistoga through Knights Valley, Franz Valley and down the Mark West Canyon to what was then the northeast outskirts of Santa Rosa.
At 52,700 acres, the Hanly fire is the largest in Sonoma County — and fourth-largest in the Redwood Empire — in the last half-century.
It pales in comparison to California's mega-fires, including the 255,560-acre Rim Fire still burning in and around Yosemite National Park, now the state's third-largest wildfire since the 1930s.
Firefighters and forest ecologists say it's unlikely the Redwood Empire will ever see such massive blazes, but destructive wildfires regularly erupt in the region, as they do all over the state.
The Hanly fire, ignited when a deer hunter tossed a cigarette into dry grass on the slope of Mount St. Helena in Napa County, remains as testimony to what happens when California's recreation-friendly Mediterranean climate bakes grass, brush and trees dry every summer.
"All it needs is an ignition source," said Michael Gillogly, the Pepperwood Preserve manager, standing on an east-facing slope that the Hanly fire's flames raced up 49 years ago. "It could burn any time."
Firefighters and forest ecologists agree: About 4,400 wildfires a year, covering nearly 220,000 acres, according to a recent five-year average reported by Cal Fire, are part of the circle of life and death in California.
"Fire is another of those processes built into the landscape," said Rick Mowery, a Mendocino National Forest fire ecologist. "A lot of California relies on fire to function in a healthy way."
Over thousands of years, the state's flora and fauna have adjusted to fire, Mowery said. Species that couldn't tolerate it "were gone long ago."
Nobcone pines can't propagate without fire, while Ponderosa pines and redwoods are cloaked in thick bark that insulates them from all but the hottest fires.
In the wake of the 29,526-acre Mill Fire in July 2012, green sprouts of oak trees and brush emerged, only to be bitten off "by something looking for lunch," he said.
However, the Mill Fire, which threatened the Colusa County town of Stonyford, occurred close to and under the same weather conditions that bolstered the tragic Rattlesnake Fire of July 1953 in which 15 firefighters were overrun and killed by flames after a shift in the wind.
Both fires erupted in the 1.1 million-acre Mendocino National Forest, which runs through parts of Lake, Mendocino, Colusa, Glenn, Tehama and Trinity counties.
The forest, managed and protected by the U.S. Forest Service, has had 29 fires of more than 1,000 acres since 1966, including four of the Redwood Empire's five largest fires, ranging from about 42,000 to 83,000 acres.
Winds up to 30 mph fanned the region's largest blaze, the Fork Fire of August 1996, which doubled in size in one day and ultimately burned 83,057 acres in Lake County, mostly in the national forest and coming within 1.5 miles of the community of Upper Lake.
Mowery said he expects the forest's larger fires to remain in the 20,000- to 60,000-acre range, largely because of topography. Valleys and foothills flank the east and west sides of the national forest, while roads and ridgelines give firefighters a chance to limit fire movement to the north or south, he said.
Sonoma County's recent fire history includes 13 major wildland blazes since 1964, with all but the Hanly Fire between 1,300 and 12,000 acres. "The potential is always there," said Eric Hoffmann, division chief of Cal Fire's Sonoma-Lake-Napa unit.
With less than seven inches of rain in Santa Rosa since Jan. 1 — one-third of the 30-year average — the region's wildfire fuels are drier than usual, he said.
Cal Fire's local unit monitors a chaparral shrub called chamise for moisture content, considering less than 60 percent a "critical point."
Samples from the Geysers typically reach that point around Oct. 15, and they already are below it now, Hoffmann said.
Still, the Redwood Empire's worst fires are only one-third to one-half as large as California's biggest conflagrations, including three in San Diego County that covered 175,000 to 273,000 acres.
Redwoods that grow abundantly here are less prone to burning than San Diego's brush and the damp ocean breeze also suppresses fire, said Marshall Turbeville, a Cal Fire battalion chief based in Sonoma County.