A new study analyzing tree rings has scoped out the origin of a mysterious sailing ship skeleton found 22 feet below the ruins of the World Trade Center in New York City. The buried ship was almost certainly built in Philadelphia around 1773, reports Fox News on Wednesday, July 30, based on a Live Science report, using the same type of white oak found in original parts of Independence Hall.
The 32-foot ship’s hull was unearthed in July, 2010, reported CBS News on July 29, and researchers have spent the past four years trying to track down its origins. Since tree rings constitute a kind of birth certificate for trees, it is possible to identify the source of unknown pieces of wood by comparing them to current and past samples of the same kind of tree. It helps, though, to make a good guess as to what samples should be featured in the comparison.
Philadelphia was home to a large ship building industry in the 18th century, so Philadelphia was an obvious choice. The rest of the world was effectively ruled out, because the hickory wood found in the keel of the ship had to have come from a source in the eastern United States – or from eastern Asia, which seemed unlikely. Analyzing the tree rings in the ancient wood formed the proof. They compared closely to sources in Philadelphia, at the time in question.
Climate clues could place the time the particular trees were cut down at around 1773 – at the time of turmoil surrounding the country’s birth. Wet years produce thick rings and drier years thin ones, so weather patterns can be followed. Some of the trees were at least 100 years old, which allowed for a long comparative record.
But figuring out how the body of the ship came to rest under the original World Trade Center is a bit more difficult. A favored theory is that the ship, after a long career sailing in the Atlantic and the Caribbean, turned into landfill in the late 1700s. Its parts were used as fill to push out the shoreline of Manhattan Island. Or, says another theory, it simply sank there.