Last winter, I started to prune a Wisteria in Jacksonville, Oregon. It's said by some to be a 100 years old. Others say its more like 40 or 50 years old. The pruning was a task. The tree service that was doing it, left deadwood up to 3" in diameter, so decayed that it could be squeezed like a sponge. And no thinning. Primarily "hacking-back". This vine is going to take years to restore decently. Last winter was mainly cleaning deadwood, light thinning and removing big branches so new supports could be slipped into place. Today's work was more light thinning and containing the spread a little. Anyhow, I took a photo of the trunk area. It's not easy to tell from the photo, but the trunk is 18" in diameter where it MEETS the soil. It looks narrower, like 14" about a foot up, but if you could stand sideways, its 16 inches in diameter there too. And about two feet up from the ground, its 16" to 18" in diameter at that point. The canopy on the arbor is 45' east to west, and 25' north to south. That's after reducing it's spread. Anyhow, the historical society has no photos from behind the historic building to document the age of the vine. Do vines like that have growth rings where an increment boring tool could detect the age? Can a vine reach that size in 30 to 50 years? Seen any examples? Place your vote, or write your knowledge and experiences. Thanks.