As I tell folks who ask, don't make American beech the centerpiece of your bonsai efforts. They are frustrating bonsai subjects! You will get, at best, two flushes of growth per year. And while that sounds good, in practice you'll find that when the growth just stops dead by summer that you most likely haven't gotten as far as you wanted in that year's training effort. American beech is a wonderful tree, but a challenge for bonsai. I say that even though I have a small one right now I'll looking forward to coming out in a couple of months. But that's one of hundreds of trees in training.