Here’s another photo of the same friend’s madake grove.
My son’s eyes, pupil to pupil, are right about 2-1/4" apart, so I figure that makes this culm 4-1/4" to 4-1/2" in diameter at his head height. That might have been the biggest culm I saw, but I don’t think there was a single culm of madake in that grove under 3" in diameter: they were all fairly close in size.
The pole I brought home, the one I cut into pieces and pieced back together on the sidewalk, was over 36’ not counting the crown, which was very roughly another 18’, and that wasn’t the largest culm in the grove, just a random one that had fallen over. If I remember correctly that pole was about 3-1/2" in diameter at the base, which looks about right from that other photo, so I’d guess the larger culm in this photo would have been 60’ tall.
P. dulcis is supposed to be one of the best for edible shoots (and is supposed to be very productive, too), but from the reports I’ve read P. atrovaginata and P. parvifolia – the two are closely related – are liked even better by people that have eaten shoots from lots of different Phyllostachys species.