The USS Constitution--one of the original six frigates commissioned for the nascent United States Navy--is technically still in active service. "Old Ironsides" earned her name during an engagement of the War of 1812 when British cannonballs bounced off her hull, leading one sailor to suggest that her sides were made of iron, not wood.
But they are indeed made of wood. Specifically, the Constitution consists primarily of White Oak. To ensure that the frigate remains in suitable condition should the Royal Navy ever again need a a good thrashing, the US Navy maintains a forest with mature White Oaks.
The Naval Support Activity of Crane, Indiana consists of 64,000 acres of forest, including the finest White Oak in the United States. The White Oak preserve is appropriately named "Constitution Grove."
-via J&L Historical | Photos: US Navy