(Adds details about prison inmate firefighters, paragraphs 9-10)
By Laila Kearney
SAN FRANCISCO, Aug 30 (Reuters) - Fire crews battling to outflank a monster wildfire inside Yosemite National Park made headway on Friday in confining flames to wilderness areas but were powerless to salvage the region's sputtering tourist economy at the end of its peak summer tourist season.
By morning, the tally of charred landscape from the so-called Rim Fire surpassed 200,000 acres (80,900 hectares), or nearly 315 square miles, three-quarters of that in the Stanislaus National Forest west of the park, fire officials said.
But a second straight night of cooling temperatures and higher humidity helped firefighters extend containment lines around nearly a third of the fire's perimeter by the start of its 14th day.
"I can't say we've turned a corner just yet, but we are making very good progress," U.S. Forest Service spokesman Dick Fleishman said. "We're going to keep chugging away."
With an overall footprint that now exceeds the land mass of Kansas City, Missouri, the blaze ranks as the fifth-largest California wildfire on record.
In terms of acreage burned, it also stands as the largest of dozens of wildfires that have raged across several states in the drought-parched west this year, straining U.S. firefighting resources.
A force of nearly 5,000 personnel are now assigned to the Rim Fire, mostly ground crews laboring around the clock with hand tools, chain saws and torches to cut fire breaks in the rugged terrain by clearing away unburned trees and dry brush.
They were supported by teams of bulldozers, water-dropping helicopters and airplane tankers carrying payloads of flame-retardant chemicals.
The firefighting force includes nearly 700 specially trained California prison inmates who work on ground crews building containment lines and as camp cooks, state Corrections and Rehabilitation Department spokeswoman Dana Simas said.
The minimum-security inmates, who cannot be sex offenders or serious violent offenders or have a history of escape, arson or gang affiliations, earn $1 a day and two days off their prison sentence for every day they work fighting fires, Simas said.
Less than a quarter of the total burned acreage from the blaze lies inside Yosemite, and firefighters there have succeeded in limiting most of the damage to wilderness and backcountry areas in the park's remote northwestern corner.
The most popular portions of the park remained open to the public, including the scenic Yosemite Valley area famed for its towering granite rock formations, waterfalls, meadows and pine forests.
Nevertheless, park officials say the droves of visitors who typically crowd Yosemite in late summer have noticeably diminished ahead of the usually busy Labor Day weekend that marks the close of the summer tourist season.
The slump in visitation has in turn put a severe crimp in Yosemite-area businesses whose proprietors were counting on a healthy summer season after last year's hantavirus outbreak frightened away many tourists.
"We're laying off just about everybody, something like 45 employees," Chris Loh, 38, who owns the Iron Door Saloon in Groveland, a gateway town 20 miles (32 km) west of Yosemite, said on Thursday.
"This is devastating for not just the businesses but the employees and the community," he told Reuters.
One notable casualty was the Strawberry Music Festival, an annual bluegrass jamboree that draws some 5,000 weekend guests to the area but was canceled when the site of the event, Camp Mather just outside the park, was closed, organizers said.
Some 4 million people visit Yosemite each year, most of them during the peak months of June through August.
While firefighters have so far prevented flames from invading the heart of Yosemite, the blaze has forced the closure of one of the park's four entrances and about half of its main east-west corridor, Tioga Road, along with numerous campgrounds, trails and two popular groves of giant sequoia trees.
Dry, hot conditions returned after daybreak on Friday. But calmer winds again favored efforts to check the spread of flames and allowed crews to continue controlled burning to create fire breaks and steer flames away from threatened or high-fuel areas.
One such containment line was being slowly burned from the edge of the Hetch Hetchy Reservoir south to Tioaga road in a bid to fully enclose the fire's eastern flank, fire officials said.
The strategy also appeared to be paying off on the opposite end of the fire zone as an evacuation alert was listed late Thursday for Tuolumne, a town of about 1,800 residents whose homes were among some 4,500 dwellings counted as threatened by the fire all week west of the park.
The fire has destroyed dozens of homes and cabins in the region, but no serious injuries have been reported. (Writing by Steve Gorman; Editing by Cynthia Johnston, Bernard Orr and Lisa Shumaker)