One thing I noticed right away with the first photo is that your dulcis made some massive gains in thickness this year so something may have been keeping it back up until this year. Perhaps next year will it will get above 2 inches.
It also looks like you thin that out very well to create an open walk through grove, as well as with many other bamboos.
None of the Dulcis culms this year were as large as the largest older culms, so there was no 'massive' size up at all, perhaps there are more culms in a similar size range that makes it look larger. Voles have really held this one back so I've been letting it run out farther to try and get it out of their mulchy communities.
That Beijing is a piece off my main clump, I made a division and container grew it for 2 years then planted it out maybe 4 years ago? It does not run far and there is actually a Dulcis culm in the midst of that clump, I had to leave it since it had done such a nice job of hiding right in the middle.
bambooseller wrote: want to share my personal bamboo in urban city
You're lucky to be able to grow bamboo in a tropical climate. I could never grow any bamboo that size, and if by fluke of nature I do get a big one, it'll be cherished and pampered like my own baby. I would never chop it down.