The world’s oldest commissioned warship is still afloat — thanks to a forest in Indiana.

The USS Constitution, named by George Washington and built with copper bolts forged by Paul Revere, was launched in 1797. The three-masted heavy frigate earned is famous nickname — “Old Ironsides” — during the War of 1812 after an astonished American sailor reportedly watched British cannonballs bounce harmlessly off the ship’s exceptionally thick oak hull and shouted, “Huzzah, her sides are made of iron!” according to the National Park Service.

While the wooden ship remains a symbol of durability and strength, its longevity would not be possible without a special 40 acres of land set aside for the care and maintenance of the ship from Naval Support Activity Crane.

According to National Geographic, NSA Crane dates back to the Franklin D. Roosevelt New Deal-era, when the U.S. government, in the depths of the Great Depression, purchased unfarmable land across the U.S. and reforested them for the purpose of creating jobs. NSA Crane was among the plots of land purchased by the FDR administration, and its 40,000 acres of hills was soon swarming with workers planting a wide variety of oak, hickory, poplar, maple and ash trees across the acres of Crane.

The onset of the war in 1939 prompted the U.S. Navy — whose weapons and munitions at the time were housed in Delaware — to seek a location that a potential enemy could not strike by sea.

Central Indiana was the ticket and so the government purchased another 30,000 acres surrounding NSA Crane.

The first administrative buildings on the base, according to Nat Geo, were dedicated in December 1941 — just a few days before the attack on Pearl Harbor.

But it wasn’t until the nation’s bicentennial in 1976 that NSA Crane reentered the Navy’s consciousness.

With attention returning to the storied, yet aging USS Constitution, NSA Crane’s concentration of high-quality white oak caught the Navy’s eye.

The oak forest is one of the few in the United States that contains centuries-old oak long and thick enough to provide the necessary lumber for the hull of the hulking Constitution.

Mature trees anywhere from 110 to 125 years old and 120 to 130 feet tall are needed for the ship that requires near constant maintenance. Its two most recent dry dock restorations — concluding in 2017 — required the felling of 114 white oaks.

Today, 40 acres of the park have been dedicated to keeping the warship afloat, where much of the timber is harvested, and it remains the only forest in the U.S. that is owned and managed by the Navy to support its fleet of old wooden ships.