Twenty-three duct-taped packages chilled in a refrigerator at Columbia University's Lamont–Doherty Earth Observatory in Palisades, N.Y., for months before scientists finally got up the nerve last December to pull them out and peel them open.
Neil Pederson's team had initially chickened out. His tree-ring experts knew that the 200-year-old fragments inside were of interest to more than just their fellow dendrochronologists.
That's because the packages were the precious raw data derived from an unusual discovery last July made by workers at the World Trade Center construction site in New York City. Three stories below street level, buried among rotten piers and other landfill once used to extend Manhattan's shoreline, emerged a well-preserved skeleton of an old wooden ship.
The aged wooden planks were in a very delicate state, making any investigation into their age and origin especially daunting.
In the days that followed the find archaeologists overseeing the excavation at the massive construction site carefully documented and pulled from the pungent mud about nine meters of what remained of the USS Adrian—named after the construction site supervisor. The original vessel is estimated to have been at least twice that long.
But the rest of the ship's story remained buried. Where was it built, and when? Where did it sail, and why?
"This shipwreck gives us a glimpse of the past—the last chapter in a complex story. We can start rebuilding and rewriting those other chapters of a ship's life by doing things like dendrochronology," says tree-ring specialist Pearce Paul Creasman of the University of Arizona, in Tucson.
"The boat had a lifetime before it got to that point," adds Creasman, who was not involved in the project.
Over the next several months, a range of experts would start nailing down some important clues. Most recent are the newly released conclusions from the Columbia team's tree-ring analysis. In their report Pederson and his colleagues suggest that the ship was likely built in 1773 in a small shipyard on the outskirts of a major metropolitan center.
A maritime historian and a plant pathologist, among others, analyzed data ranging from horseshoe crabs to shipworms to help corroborate these findings and fill in other blanks.
"Various aspects of scientific research have contributed pieces to the puzzle," says Molly McDonald, an archaeologist with the firm AKRF, Inc., the environmental and planning consultants monitoring the World Trade Center site for the Port Authority of New York & New Jersey. "All of them help us to understand a moment in history."