A new report warns that continued construction and remodeling could cost the town its coveted and lucrative spot on the National Register of Historic Places - a landmark loss for a place that distinguishes itself among North American ski resorts by touting its Old West image.

Park City's multimillion-dollar marketing efforts also focus on summer tourism in this booming community in the Wasatch Mountains where Main Street harks back to the 1880s.

But the hyper-economics that spurred the rapid rise in real estate values here could threaten the historic district - and with it the cachet that has propelled Park City to prominence.

New construction is out of scale with the old mining town, and modifications of aging structures may have diminished their historic value.

Those are among the findings in the "Historic Property Inventory," a report by consultants Dina Blaes and Beatrice Lufkin. The City Council commissioned the one-year study so it could pinpoint the number of historic structures.

"Park City's Main Street Historic District has undergone changes over the last two decades [that] have diminished its integrity and could result in delisting from the National Register of Historic Places," the report states.

That does not mean Park City has not worked hard to protect its history, Blaes said in an interview this week. But there is a significant dichotomy at work, she said, referring to structures such as the six-level, 94,000-square-foot Sky Lodge being erected near Main Street.

"The enormous development is an intrusion [on Main Street] yet, in its own sales brochure, it touts the historic district," Blaes said.

The report cites five similar encroachments. Among them are the Main Street Mall, a large contemporary building put up in the early 1980s, and the Galleria, a towering red-brick structure built near the bottom of Main a few years later.

Beyond that, the inventory identifies a stark reduction in Main Street buildings that comply with National Historic Register requirements. From 1979 to 2006, the number of Main Street structures that met that definition dwindled from 65 to 34. Most were remodeled to the point they no longer qualified for the register.

"Park City has to decide: 'Do we want to embrace national criteria? Or are economic pressures so great we want to develop our own criteria?' " Blaes said.

Among the report's recommendations is that Park City adopt more-stringent design guidelines and development standards in the Main Street Historic District.

Nonetheless, most visitors strolling along the storied street feel like they are in an old mining town and could not identify buildings that don't qualify for historic status, said Hal Compton, a research historian at the Park City Historical Society & Museum.

Until they see the Main Street Mall.

"If they walk up Main Street with their eyes open, they'll see all these historic buildings, and then they'll see this big mall. It's completely out of place. It should never have been built."

Compton puts the Sky Lodge in that same category.

"I cringe at that new hotel being built at the bottom of Main Street," he said.

But some trade-offs are necessary in a small, historic town that has morphed into a world-class destination, said City Councilman Jim Hier.

The hotel's builder, Cloud Nine Resorts, has promised to maintain the Union Pacific Depot, Utah Coal & Lumber and a third historic structure on its property.

"It worked out to be a decent compromise," Hier said of the city's approval of the hotel. "You have to be able to give something to the landlord so they can realize the economic value of their property."

Park City has made great efforts during the past quarter century to ensure its historic district survives, according to Mayor Dana Williams, whose family once owned property there.

"I have a picture of my mother on Main Street with a cocktail and three buildings on fire. Nobody was putting them out, because no one gave a damn back then."

The City Council will revisit the report Jan. 25 to determine if changes to its Land Management Code are needed to preserve Main Street.

"Regardless of if we have the national designation," Williams said, "we'll still have a charming town."

csmart@sltrib.com