In my neighborhood old-growth forest in the city, one of the black oak logs looks to have 260 rings. It was a fairly careful count, though the most accurate way of counting rings is to cut and polish a slice of the log--not to count rings in the field. This number is significant because the oldest registered black oak is one with 257 rings, and that one lived in Tennessee.
Here is Neil Pederson's blog, "The Broadleaf Papers," which focuses on the ecology of hardwood forests. These old black oaks that live just up the hill from me are my "Charismatic Megaflora."