There is a very old tree near where I work, in Deptford township, along the south bank of the Timber Creek. It's called, locally at least, Clement's Oak, and is thought to be of similar age. Local tradition has it that when the first white settlers came to the area in the first half of the 1600s, it was already the largest and oldest tree around, and became a landmark. It sits unceremoniously behind the loading dock area of the Walmart on Clements Bridge road and access is somewhat blocked by a chain link fence, but it's still worth a look if you're in the area.
The 1217 is likely just graffiti. There is a little bronze plaque on that stone, and last year the township spread some mulch around it. I work just down the street in Runnemede and I didn't know about it until maybe two years ago.