Useful video from Geoff. Much of my chop is smaller tender plants like comfrey. I chop and drop when these plants start closing in on the mother plant in the trio. My B.Locust and some other "trees" are getting bigger and I will have to take into consideration the time of year.
I find that I have enough biodiversity at this point that I'm doing chop and drop as I weed and clear some room between plants but I will have to Pollard to keep the nitrogen fixers in check.