I'd let it make its own choice.

Here in Boston at the Arnold Arboretum and across the river at Mt. Aubun Cemetery (I was there Thursday) large numbers of griseum grow and prosper. I have never seen a single multi trunk tree.

I have also grown these trees for more than 25 years and several thousand seedlings have shown no inclanation to multi trunks. I sell some at 2-3'. All my seeds I collect from single trunk trees, only becaus thats all we have here, that I have seen. Evan the dozen or so trees that the rabbits have eaten the branches back to the trunk seem to have no desire to rebranch near the ground.

If you have more than one seeding why not try a few?

If your in a heavy snow area it may be a concern.

Ron

In April a grower in Washington state supplied my favorite local nursery with some clumped paperbark maples that were from 4 to 5 feet tall. They were bare root and I bought one because I thought they had been grown just like you described you wanted to do.

The local nursery owner soaked the tree's roots in a root stimulator for me and I planted the tree to grow in a pot until the roots were strong enough for replanting in the dirt this coming September. At the time of potting, I still believed that the three trunks were growing from one root system. To my surprise, I found that not to be the case.

Only two of the trunks leafed out, and the third trunk produced buds that would not leaf out. After several weeks of waiting I finally repotted the tree in a new pot with better draining potting soil. At that time, to my surprise, the tree trunks separated. I could see that they each had one independant main thick root, each with just a few feeder roots growing. The trunk that was only budding had the least amount of feeder roots.

So I called the nursery and discussed the discovery with them. They told me that is how growers produce multi-trunk Paperbark maples. She said that all of the ones that the supplier had shipped them were the same way and they were labeled Clumped Paperbark maples.

A few days ago, I decided to again purchase one of the two remaining CPMs that they had not yet sold. That tree looked better filled out and had grown a better root system than the first one I had purchased.

I noticed that the trunks on the newly aquired tree were about 6 feet tall and very nicely leafed out. But it was clear that to keep the trunks close to the same heights the nursery had to purne the main leaders to all be close to the same height at the 6 feet level. If I do not want the leader trunks to branch at that height, I will need to prune the remaining branches from that point to only grow with one leader for each of them as they acquire more height. I will most likely then let each of them grow in a modified leader form once they reach nine or ten feet high.

Since your sapling is still so short you should have time to find two more single trunked paperbarks about the same height to prune the roots in such a way that all three tunks can survive and grow together and form one three tunked clumped version of the tree.

Just make sure that all three trunks' roots are pruned to about the same size. Then plant them close together so that as the roots develop they will grow and interconnect with each other.

When I repotted my first tree I separated the trunks about 5 inches apart from each other in the pot. but the nursery had kept the trunks of my second tree very close almost touching each other. When I purchased that tree I asked the nursery owner if that close spacing would cause problems as the individual trunks tried to spead, and he said that the tree would adjust itself and have no problems with all the trunks starting out that close. It will take years of growing before I can see the proof that he was correct. He should know more about it than I, so I plan on leaving the tree as is; especially, since the tree is doing so much better than my first one I would not want to take the risk of harming the tree by messing with the trunks' spacing.

Katrina, I wouldn't be all that concerned with the three being exactly the same height. All that work and nature will do what she wants to!

Thanks for the story, I'm sure there going to be the focal point in your yard.

Ron

Ron, it is interesting to see how casual and relaxed about how the trees turn out. Maybe when I have had mine longer I will get more relaxed about them also.

It is nice that you have grown so many and have lots of experience with Paperbark Maples.

Can you tell me the closest to the foundation of house or a patio a Paperbark Maple can be planted with out risking the PBM's roots from damaging the cement when the tree matures. Or is this type of tree not a concern with that problem like other taller and faster growing maples are?

Well, I went ahead and pinched the tree back anyway. I was expecting 2 stems to emerge. To my surprise 6 stems have developed. This is going to be one unique tree. I realize it will be more susceptible to rot and breakage, but it could also look great. One tree with 6 beautiful stems with that beautiful bark. I guess time will tell.