Is it too late to trunk chop a Chinese Elm in Floridas climate? Also, is it safe to chop it below the first branch???
It should be no problem IF the plant is healthy and currently growing with good vitality - especially if some of the spring flush has already matured. Yes - it's safe to chop it below the first branch. If the tree is very old, most of the back-budding will occur from the cambium around the wound, so I would be sure to cover well with cut paste (I apply water-proof wood clue to the cut) or similar to keep the wound from drying back. If the tree is young and the bark still pretty smooth, it will back-bud randomly along the trunk. Again though, you can't cut back a tree that's circling the drain & expect it to back-bud fir you. With most trees, you wouldn't want to risk cutting back so close to the spring flush, but U parvifolia is so genetically vigorous that trees in good vitality should tolerate it fine.
The tree is healthy and growing like a weed. It's only a couple of yrs old so the bark is smooth.