All are easily kept to a single trunk, provided you start with a single
trunked specimen. The Kousa has a propensity to be a low spreader, meaning
many primary branches spreading out near the ground. The Trident Maple
enjoys suckering at the base so it might need periodic pruning to discourage
this.

Dave

"Stuart E. Weiner" wrote in message
...
I have decided to plant one of the above--Kousa dogwood, Amur maple,
Trident maple, or Triflorum maple--in my front yard as the "featured"
tree. It is important that the tree have a single trunk, ideally 4 to 6
feet off the ground. Which of these would I likely have the best luck
with training to have a single trunk? Are there specific cultivars that
achieve this?

Thanks.