The practice of using live oak in shipbuilding was well established in America by 1700. Early famous live oak vessels include the Hancock, an American revolutionary privateer, and the USS Constitution and Constellation, built in the 1790's. The Constitution saw action against the British during the war of 1812, receiving the nickname "Old Ironsides" due to the strength of its live oak construction. To ensure a future supply of the invaluable live oak, the United States Government reserved thousands of acres of southern woodlands to protect the tree from timber interests. The need for wooden ship timber diminished with the advent of iron and steel warships. However, in 1926 live oak timbers from the Pensacola area were found to be useful in the restoration of the USS Constitution, a National Monument. Today, as a reminder of the importance of live oak to our heritage, its story is told at Gulf Islands National Seashore.
In 1828, the United States purchased the land which comprises the present Naval Live Oaks Area, with the goal of reserving its valuable timber resources for ship building. President John Quincy Adams authorized the establishment of the first, and only, federal tree farm on this site, beginning operations January 18, 1829. Superintendent Henry Marie Brackenridge, who lived on the tree farm, experimented with cultivating the live oak tree. He was perhaps our country's first federal forester.
http://www.nps.gov/guis/historyculture/the-live-oak-story.htm
They are amazing trees.