My dads got a big slice of oak like that in his garage that he said he cut with his great grand dad in the early 70's I wonder how you could tell when it started it's life that would be pretty neat. I'll have to snap a pic and count the rings next time I'm over there
If he knows the year he cut it and if it was alive at the time, the outermost ring would be from that year. He could count backward from there. Should be able to figure it out to plus or minus a couple years.
Sorry Jon_E got a quick look and some story on the slab tonight. Roughly 30" has three hearts to it since dad said it was a slice from where the top started into three leaders. He got to cut the top off and buck it into firewood. He said the trunk was near 5' at the bottom and where he made the cut to take the top off was roughly 50' up plus another 30' ish for the top. He wasn't allowed a slice off the bottom since his grandpa and great grandpa were sending it to the mill. Dad also said 1978 he cut it with the 041 his great grandfather had just given him that day. I counted 77 rings from the bottom right edge to one of the hearts!
I should have zoomed out the ol 041 sits on the shelf next to it, you can see the bar tip . I'll have to get it down and do some real measuring and counting