Acer Griseum is a naturally upright grower and rarely if ever forms a multi-trunk tree. There has been a trend for some nurseries to sell multiple saplings that have been grown together to look like a multi-trunk tree. My suggetion would be to keep the low branches to replicate it as much as possible.

I agree with with scross4, I know some one else said they topped their tree and it suckered from the base. I have grow hundreds of griseum, if it happened, its a very rare occurrence. And that's why they pot up multiple seedlings.

Ron

I have a paperbark maple seedling that is a year old. I pinched the top out this summer and it produced two nice trunks instead of the single. It is growing well and is now almost 3' tall. I think this will enhance the appearance of the tree as the bark is the main appeal. I am happy with the appearance. I don't know how big your tree is yet, but with a seedling it was easy to turn it into a multistemmed tree.

Many trees are upright growers by nature, but can easily be induced to form multiple trunks. It is a common bonsai practice & referred to as a trunk-chop. Once the tree is well established, feed it particularly heavily after the initial spring growth push ends. In August, stop nitrogen applications & apply 0-10-10. The following spring, before buds move, make a diagonal cut with a very sharp saw or lopper a few inches above the basal flare. This will activate dormant buds & multiple new branches will begin growing. Select your new trunks from those growing in appropriate places, and remove the rest as they occur. The wound will quickly heal. Painting the wound with waterproof Elmer's Glue, being sure to seal the exposed cambium, will help keep the cambium in the wound area moist, prevent the wound from drying, and die-back of cambium in the wound area. This isn't to hasten healing per se, but to allow new buds to activate nearer the cut. In the case of trunk chops, it does, in the end, allow the wound to close faster.

Al

Thanks everyone. My tree is not quite a sapling. I would guess it is a couple years old. It's about 6 feet tall and the trunk is about 1 1/2 inches in diameter. But there are a few young branches very low on the trunk. I will prune them off unless I can somehow train those to look like an additional trunk.

You can utilize existing branches by securing them to the trunk with something that will not damage the cambium. I have used strips of old towels or sweatshirts to do this. The branches may need to be raised to vertical in more than one increment to allow small fissures in cambium to heal and prevent branch breakage. Best time to do this is in late winter or early spring before sap begins to rise. If you do it now, the cracks in the cambium will not have time to heal & branches could dry out & die over winter. How many trunks are you envisioning? Compositions with 1, 2, 3, or 5 trunks look best.

The tree will appear more natural as a "clump" if you chop according to my initial outline, though.

Al

Brickell/Joyce, 'Pruning & Training' has 3 diagrams showing "Pruning to form a multistemmed tree on a low trunk" over a 3 year period in their section on maples (pp. 52-53). The specimen drawn by the artist starts at about the height yours is now, is cut down to about 20". It is exactly the procedure you are asking about.