Maybe let it root out first and then prune next year, when you may also have a better idea of what to do. Top pruning at planting time reduces root growth.

Leif,
Too much top and a little root ball. There needs to be balance. Cut the main leader in half and also all the side limbs. It will grow much stronger if you do. Some shippers will have already done that.
Bberry

Wow, two contradictory answers so far.

Let me add my opinion as well....

I would only prune out any branches that are crossing and which would likely rub against another branch, thereby leading to the possibility of fungal or other disease. Next year I would consider making more pruning decisions with regard to the final shape of the tree.

btw, that's a pretty healthy looking Northstar. The one I planted 2 years ago was much smaller than that one.

~Chills

Growth of new roots prompted by opening of dormant buds at branch tips, which send hormones down to the root ends upon opening. Growth of new roots supported by nutrients stored over winter in branches. Reduction of top reduces potential for strong root growth - and vice versa. That is why roots of bonsai are pruned, to reduce the top growth. Cutting the top back or thinning it out substantially makes the plant grow less strongly, rather than more. The false impression that the top is growing more strongly is created by the fast-growing watersprout or whip-like shoots it throws up to quickly replace the growth it wishes you hadn't pruned away. Typically a few of these are produced where it has several shoots before, overall increase in size of plant body actually being less than if the top had not been pruned.

Thanks for your input, everyone. I think I'll go with a more moderate pruning scheme for now; that is, only removing the braches that are clearly problematic, and leaving any other pruning until the tree is more established. That seems like the safest route.

Once again, I really appreciate your help.

Leif