If you are hinting at what I told the new guy asking about his little zelkova and pruning in summer, that is the best advice for someone who doesnt know. I know as well as you do that most pruning can be carried out at anytime if you know what you are doing.
There is no real winter in San Francisco. The problem with harsh treatment is the question of how hard it is for the tree in the period immediately following. Not the least of which is freezing roots. Length (with depth ) of "winter, too, like 5 months of zero growth under 32°F.I agree- least of all elms.
Last year I ripped a 2 yr zelkova out of my grow bed in august (literally pulled, no digging at all) cut off the bottom inch of the trunk/roots and all the roots that werent perfect and replanted. It put on 4’ of growth this year. But I would never recommend that to someone.
Ive always felt that if one has to ask, then one probably does not know. And in that case, the safe route is the best route until people can make their own educated decisions.
I Appreciate the discussion and have always admired your trees
