Prune Double-Trunked Tree

Q: I bought two of these trees 18 months ago. They are about 8 feet tall and growing well, except one has a double trunk. Should I prune away the smaller trunk even though it is close in size to the main trunk?

A: Your dawn redwood may be only 8 feet tall now, but it will soon be 70 feet tall. When that happens, even a gentle breeze can put a great amount of strain on the joint between the two trunks. The smaller trunk will pull away from the larger one with tremendous force. This will split the tree, and it will likely rot and die.

Cut the small one as close as you can to where it attaches to the larger one. Leave a little ring of bark on the big one to begin the healing process. In a few years, you’ll have a target-shaped scar and a single trunk to grow properly. If you bought this tree at a nursery, it would have been a simple task for them to clip off the smaller trunk before it got so large.