rockm

I think you must also take into account the species, here. Birch are notoroous for dropping branches for no reason, on a whim, if they're pruned wrong, too hard or not at all.

The branches are a fleeting part of a birch bonsai. You can't build an image around them. It's best built around the trunk, which in this case is terrific.

I have a friend who has been hacking away at a few birch for some time trying (and sometimes succeeding) to make them into bonsai. His designs have been frustrated by this species habits. He is constantly retyling them when the branches simply die off.

Some of the best results are sometimes already before us and we don't know it until someone points them out...