Thanks,
I have heard different views, and I thought spring was best, I did my tropical trees a few weeks ago, but this is my first non tropical tree besides the junipers I have so wasn't sure.
Non tropical trees have a yearly cycle. There is a dormant period which is followed by a period of rapid growth. The best time for repotting is just at the beginning of rapid growth because that is when the cuts you make in the roots heal fastest. Second best is in the dormant period because then the tree is not dependent on the roots and it will experience less shock.
Maples are easy because the leaf buds start to swell and give you notice that it is time. You can't set a time on your calendar because what matters is when the tree is ready. I had elms leaf out January 7 this year, and the last tree came out in late March. Watch the tree.
The following user(s) said Thank You: Clicio, Caryboy60013