NEW YORK >> The blue-collar shop floors fall silent, find new life as artists’ studios, then exchange their 19th-century guts for 21st-century wine cellars, marble bathrooms and private gyms: So goes the story in a city where time does not stand still for long, and where a neighborhood’s shifting fortunes can be told through its old warehouses and factories.

In the process, the city coughs up timbers that were logged and hoisted into place when it was almost young. New York is the country’s largest repository of the lumber that formed the spine of the Industrial Revolution — a five-borough safe deposit box for New England white pine and spruce, Pacific Northwest Douglas fir and, especially, Southern longleaf pine.

Vast hoards of the longleaf pine are entombed at each base of the Brooklyn Bridge. It once underpinned the New York City subway tracks. It endured the trampling of 150 years of Domino Sugar Factory workers in Williamsburg, buttressed the warehouses of Tribeca and bore the weight of Brooklyn’s waterfront depots.

Now the sugar factory is being converted into condominiums; Tribeca lofts are among the city’s most expensive real estate; and the East River storehouses have been razed to make way for more condominiums. And the longleaf pine has found new purchase.

The timber of the industrial age now graces Thomas Jefferson’s Monticello and the stately Maryland chamber where the Continental Congress once met. You can walk on it at the new Whitney Museum and New York’s Patagonia flagship store. Much of it is being reclaimed by the region it was hauled away from, when northern timber barons descended on the South’s millions of acres of virgin pine after the Civil War.

“The South was an extraordinarily poor region during that time, and was nothing but a resource base, and most of this wood came to New York,” said Larry Stopper, a partner based in Virginia at the reclaimed lumber firm Bigwood. “Now the industrial cities of the North are transforming themselves, and the South has plenty of money, and people want their old wood back.”

By now, as shelter-magazine readers and Pottery Barn customers alike know, reclaimed wood — salvaged from sources that include bourbon tanks and mushroom farms — has gone mainstream. In the case of New York City, salvaging wood also means salvaging the city’s past.

As the timber industry gobbled through northeastern and western forests, it began turning to the longleaf pine, also known as yellow or heart pine, that covered as many as 90 million acres from southeastern Virginia to eastern Texas and northern Florida, a forest where naturalist John Muir wrote in 1867 that he had “sauntered in delightful freedom.”

Some of the trees were three centuries old. Dense, durable and saturated with resin that made it unusually resistant to rot and insects, the timber proved rough work for builders to mill. But in the decades before steel began to dominate, longleaf pine was the strongest material around.

“Everybody in the wood business says the longleaf pine tree was the best wood the Lord ever made,” said Pat Fontenot, owner of Olde Wood Accents in Washington, Louisiana, an antique pine dealer. “If it wouldn’t have been for the longleaf pine tree, we wouldn’t have been able to do the Industrial Revolution.”

The largest mass of longleaf pine in the city probably sits under the two towers of the Brooklyn Bridge. Completed in 1883, the bridge was built using caissons, essentially enormous airtight timber chambers that engineers sank into the riverbed, allowing workers inside to dig deeper into the earth below and workers above water to construct stone towers on top.

By 1938, the Great Southern Lumber Co., based in Pennsylvania, had sold its last longleaf pine log. Only about 3 percent of the original old-growth forest survives, according to the U.S. Forest Service. Pine harvested today comes from farmed trees that are cut down young.

The only way to find original-strength longleaf pine these days: Mine it from buildings like the Domino Sugar Factory or 443 Greenwich St. in Tribeca, the brick and mortar vertebrae of northern cities’ industrial might.

“It’s a Southern tree that has been a part of New York City for 150 years,” Alan Solomon, owner of Sawkill Lumber, who hunts down old lumber, from the Coney Island boardwalk to a Western Beef supermarket in the Bronx, said during a recent expedition to the Tribeca building. “The city’s always reinventing itself. Stuff’s always getting knocked down.”

It has taken Solomon’s team a year and a half to strip the brick-and-stone Romanesque Revival plant in Tribeca, finished in 1883, of all its pine. The building’s tenants have included the Novelty Toy Co., which is said to have produced the first teddy bear; the American Steel Wool factory; a printing house; and, as manufacturing jobs drained out of the city, studios for architects, filmmakers and artists.

Its newest incarnation is as 53 large, lavish condominiums financed partly by a Russian billionaire. The asking price for one of the most expensive units is $53 million.

The building’s lumber was stripped of nails, dried, milled and sometimes stained again. Fontenot bought a batch for several customers in Louisiana who were seeking to restore old homes or to build new ones in classic Southern style.

Some of the wood was originally logged not far away in Bogalusa, Louisiana. These days, it can go for as much as $14 per board-foot, or a foot-length of a board 1-foot wide and 1-inch thick.

Susie Mitchell, who runs a home-building business with her husband, bought pine from Tribeca and the Domino factory for their own home. “Definitely in this region,” she said, “if you did a beautiful home and didn’t put antique pine in it, you’d be, like, ‘Hmm, it’s nice, but …’”

George Washington apparently thought so, too. After the pine he bought for the floors at Mount Vernon was stolen, he wrote to wood suppliers across the region looking for more. They pointed him toward the builders of the Maryland Statehouse, where a nearly flawless set of pine planks had been used for what is now called the Old Senate Chamber — the same room where Washington had resigned his commission as commander in chief of the Continental Army and where the Treaty of Paris was ratified, officially ending the Revolutionary War.

The room recently underwent a seven-year restoration. Its new — and yet very old — floorboards came from the Domino factory. Only a few made the cut for the restoration, Michael Day, chief preservation officer at the Maryland Historic Trust, said. The standard? “Perfect.”

Pine from the Domino factory also helped restore the nursery and the venetian blinds at Monticello, where the restorers wanted all the boards to “match the exact same thickness and length and look” like the originals, said Paul Atkinson, an owner of Southend Reclaimed in Virginia, which supplied the lumber.

Not all of the pine returns to the South. Wood from the Domino factory lends the Patagonia and Filson stores in Manhattan authentic-looking backdrops to ultralight down jackets and rugged-look briefcases.

At the Roosevelt Island duplex of Nina Tandon and Noah Keating, both born-and-bred New Yorkers, the wood pays homage to their native city, a small piece of an East River landmark always just underfoot.

Less heralded bits of the area’s industrial past have found new uses in its present, too. The new Whitney Museum, which New York Times architecture critic Michael Kimmelman hailed as “a glittery emblem of new urban capital,” has floors all made of longleaf pine salvaged from the Paul G. Mehlin & Sons Piano Co. factory (later a major tobacco pipe manufacturer) in West New York, New Jersey; the Maidenform bra factory in Bayonne, New Jersey; and the Philip Morris factory in Louisville, Kentucky.

Many museums want a pristine floor; at the Whitney, the architects kept the outlines of nails in the wood. “The Whitney was interested in a kind of rougher or more honest kind of working art space,” said Toby Stewart, an architect who worked on the project under Renzo Piano, who designed the building.

The piano factory and the Philip Morris plant have been torn down. And the Maidenform factory, where workers once produced bras and, during World War II, military parachutes and carrier pigeon vests, is now home to Brooklyn-style lofts.

In Brooklyn itself, the pace of recycling has quickened, with warehouses and factories along the borough’s north waterfront being razed or converted.

A few years ago, a complex of cold-storage warehouses hard by the Brooklyn Bridge that once stored perishables shipped to the city were torn down to make way for Brooklyn Bridge Park. The pine that once buttressed floors and roofs became benches, picnic tables and playground equipment. What preserved the lumber’s strength for 170 years now protects it, not too far away, from the snow, the rain and the sun.