While the memorable "Bonanza" theme music played, Ayres' map appeared, then dissolved in flames, revealing the Ponderosa ranch's inhabitants on horseback — the Cartwright clan played by Lorne Greene, Michael Landon, Dan Blocker and Pernell Roberts.
Ayres' original Ponderosa map had hung for decades in the home of "Bonanza" creator and producer David Dortort, but Dortort's family donated it to the Autry National Center of the American West after he died in 2010.
After the Autry Center announced last June that the map of the fictional Ponderosa was on permanent display, Ayres and family members visited the exhibit three times.
Upon re-encountering the map for the first time in more than 50 years, Ayres exclaimed, "Oh, for goodness' sake! I had no idea where that had gone," Tessie Borden of the museum's staff wrote on the Autry website after his first visit in July.
At first, the artist "didn't think it was the original map, because it was so big," said Don Richards, Ayres' son-in-law. "It was a neat thing, and he was just enjoying it."
An observant reader of the museum's Trading Posts blog had noted that the museum's Ponderosa map differs in several small details from the one that burns in the opening credits of "Bonanza," said Autry spokeswoman Yadhira de Leon.
The Autry made inquiries with experts, who said that to avoid burning the original rendering, "Bonanza" producers probably would have had numerous hand-drawn and perhaps inexact copies made for the purpose of torching them until they achieved the right effect for the opening sequence.
Ayres was born July 28, 1913, in Lansing, Mich. He attended what is now Michigan State University but left to help with his father's real estate and property management business during the Depression.
Exempted from military service because of severe allergies, Ayres worked as a navigator for Pan American Airways during World War II. He studied at the Academy of Art in Chicago and at the Chouinard Art Institute and Jepson Art Institute in L.A.
After working as a commercial artist, he illustrated "The Golden Treasure of Bible Stories" and other books.
His religious artwork landed him a job at MGM when the studio needed set illustrators for the big-budget 1959 epic "Ben-Hur."
As a set illustrator, his work involved turning blueprints and technical specifications given to him by set designers into drawings or paintings that would help guide set builders.
He moved on to Paramount and Disney, where he was a set illustrator on hundreds of films, including "Blue Hawaii" (1961), "The Man Who Shot Liberty Valance" (1962) and "The Black Hole" (1979).
His last assignment at Disney before retiring in 1980 was creating artwork for restaurants and other venues at Epcot Center in Florida.
After his first wife, Geraldine, died in 1980, Ayres remarried. His second wife, Lucy, died in 1996.
Besides his daughter, he is survived by his sister, Peg Boehm; and two grandchildren.
Los Angeles Times staff writer Dennis McLellan contributed to this report.