Now that’s a lot of green for Central Park!

A billionaire hedge-fund manager is donating $100 million to the Central Park Conservancy, in the largest gift ever to New York’s beloved opened space and is believed to be the largest donation to any park in US history.

John Paulson, 56, announced the mind-blowing contribution with Mayor Bloomberg at Bethesda Fountain in Central Park.

Paulson, who joined the conservancy board in June, said he wants to make New York City a center of his philanthropy and decided Central Park, which he has visited regularly since his childhood and where his grandparents courted, should be No. 1 on the list.

“It’s been an important part of my life and my family’s life for a very long time.” he said. “I wanted the amount to make a difference.”

Paulson was previously best known for making a killing in 2007, short-selling the mortgage and securities market. He reportedly made $4 billion by anticipating the monumental burst of America’s housing bubble.

“It is a great privilege to be able to contribute to the Central Park Conservancy, one of the most important cultural institutions in New York,” Paulson said.

Paulson has enough loose change to make the massive donation. He’s No. 28 in the Forbes 400 and No. 61 in the list of Forbes Billionaires.

He’s also been a generous donor in the past:

–The NYU alum and trustee gave $20 million to the school in 2009.

–He made a $5 million gift to Southampton Hospital, near his summer home.

–The Wall Street titan donate $15 million to a maternity hospital in Guayaquil, Ecuador, where his dad was born.

Half of Paulson’s $100 million will be added to the conservancy’s endowment, which now stands at $144 million.

The other $50 million will go towards dozens of capital improvement projects, including the heavily-trafficked southwest entrance that conservancy president Doug Blonsky said was in dire need of an upgrade.

“This is a fantastic gift, John,” declared Mayor Bloomberg. “It’s not a gift to the park, but a gift to everybody…. There will be a handful of people who say,’Thank you, John.’ Most people aren’t going to know…But most importantly, you will know that you made the difference.”

Former Parks Commissioner Adrian Benepe called Paulson’s extraordinary gift a game-changer.

“This is a really big deal. This $100 million given to Central Park is three times more any previous gift. It sets a very high bar,” said Benepe. “It will resonate around the country like a gunshot. Other people who have done well in life will think about making a big gift to their park.”

The largest previous donation for a park was the $40 million pledged for a Brooklyn indoor bicycling facility.