Nice one there Hiker.
I found a 3 prong at the bottom of a bluff last year in a spot that I walked right by two years earlier looking and it was in a real easy place to spot, but I did not see it two years earlier. I expect it had been browsed - it was in a easy place for deer to get to too.
But it was about a 8-10\" tall 3 prong - did not look special at all.
When I got to digging it I was like you - I was impressed with the root neck and scar count.
I think it may have been in the 40 year old range - possibly more.
Here is a pic of it - not a real big root but a impressive root neck.
TNhunter