The world-famous public-private partnership that has transformed Central Park into an 800-acre emerald celebrates its 25th anniversary tonight at Tavern on the Green.

The black-tie party is the Central Park Conservancy’s official thank-you to the trustees, donors, and volunteers who helped remove the graffiti, trash, chain-link fences, mud, and crime that were prevalent in the 1970s.

The conservancy’s founding president, Elizabeth Barlow Rogers, will be there, as will the former commissioner of parks, Gordon Davis, and 300 other park luminaries.

Back then, the idea that a group of private citizens would band together on behalf of the park was considered outlandish. Today the conservancy manages the park and contributes 85% of the park’s $25 million annual budget.

For the 59 business, social, and philanthropic leaders who are trustees of the conservancy, 44 of whom are expected at the silver anniversary tonight, it is some of their most fulfilling work.

“What’s special about this board particularly is the universal enthusiasm for the park that trustees have,” the chairman of the conservancy, A.J.C. Smith, said.

“This board is like no other board I’ve been on,” trustee and businesswoman Elizabeth Varet said. “Elsewhere, there are factions or the chairman becomes some little dictator. Not here.”

The staff is grateful for their input. “The trustees and donors are part of my everyday life,” the conservancy’s current president, Douglas Blonsky, said. “They know more about the park than almost anyone.”

One of the conservancy’s original trustees, Richard Gilder, has a vigilant eye. The financier, an owner of The New York Sun, walks through the park every morning.

“I’m not a nature lover at all. I’m a New Yorker. Animals? Please. But when I see some bum lying on a bench I send off an e-mail to Doug. I’m on patrol,” Mr. Gilder said.

He once noted the new metallic lampposts going up throughout the park. “They didn’t look park-y. They were very Triborough Bridge Authority. I persuaded Doug to paint them all black,” Mr. Gilder said.

He is a generous supporters of the park. In 1993,he gave a $17 million challenge grant. The Wonder of New York campaign raised more than $50 million, which helped complete restoration of major landscapes in the park.

Mr. Gilder first became involved with rescuing the park in the early 1970s, when he and George Soros founded the Central Park Community Fund. The fund commissioned a study on park usage. One of its recommendations was to establish a board of guardians.

That became a reality when the conservancy was founded in 1980, superceding the Community Fund and the group Ms. Rogers had founded, the Central Park Task Force.

The success of the conservancy owes much to the Women’s Committee established by Jean Clark, Norma Dana, Marguerite Purnell, and Phyllis Cerf Wagner. Among its many accomplishments, the committee brought social prestige to the conservancy, along with the devotion of women living along the perimeter of the park.

“The four of them were much more fancy than the board. They looked down on the board and we looked down on them. They really did a great job,” Mr. Gilder said.

Some park supporters have affection for the park generally, while others are more focused.

“One of the things I’m most happy about is the money my family gave to redo the Shakespeare gardens in memory of my mother [Roberta Rudin],” Eric Rudin,a trustee, said.

“I love the park, period. I use the park as my office and playground,” a businessman who lives in Los Angeles and New York, Stanley Chais, said. He funds the upkeep of Naturalists’ Walk.

Many of the park’s supporters grew up near the park. Ms. Varet may be unusual for her fond childhood memory of all the trash lying about.

“There were all these Cracker Jack and Planters Peanuts wrappers. If you picked up 25 wrappers and sent 25 cents in, you could get a ‘Paint Without Paint’ book. That was my dream,” Ms. Varet said.

Today Ms. Varet finds the park “beautiful, radiant, and welcoming.” As chairwoman of the development committee, she sometimes wishes that an acre of the park had been left alone, to show people how much it has improved.

Physical change in the park isn’t Ms. Varet’s chief motivator, though.

“The intangible part is just the best. This park has soul. People feel comfortable. They love to let their dogs loose. I once asked Doug how he feels about people picking the daffodils. He said ‘That’s all right. It’s meant to be that way.'”

A highlight of the event tonight will be a live auction of “once-in-a-lifetime Central Park experiences,” including the chance to mow the 14-acre Sheep Meadow, have a sleepover in Belvedere Castle, take a trolley tour with historian Barry Lewis, and visit the top 10 trees with the park’s chief horticulturist, Neil Calvanese.

After a champagne toast, guests will dance to the music of Alex Donner and his orchestra. Unlike the conservancy’s celebrated fund-raising events, this invitation-only gala carries no cost to attendees. Tavern on the Green is underwriting the cost of the dinner, which includes a grilled shrimp salad, beef with black truffle madeira wine demiglace, and deep-dish apple cobbler.

As much as the 25-year mark is an occasion to look back, it is also a time to look forward.

“We are at a crossroads. This is truly that moment in time when we can set up the park’s future so it can never fall back again,” Mr. Blonsky said.

Mr. Smith reiterated the sentiment. “I’m not coming up with radical new ideas. My job is to ensure that the park continues to be what it’s like now, and to make sure that as many people as possible know how the park works,” he said. “The moral support of New Yorkers is as important as the financial support.”

agordon@nysun.com