When should I start pruning?

[mswabbie]

I planted ten hickory trees two years ago from nuts. They are now about 4 feet tall and 1/4 to 3/8 in diameter. I would like the trunks to be straight and the first limbs to be about 10 feet from the ground. When should I start thinking about pruning them to achieve this.
Thanks

 

[gumneck]

In what I do with training fruit trees/vines, the earlier in its life that I can begin to shape it the way I want it the better and faster I can help the tree/vine achieve the goal.

Not sure if this would apply to Hickory, but I think it might.

 

[treeseer]

http://www.treesaregood.com/treecare/pruning_young.asp

Not too much at a time or you'll starve your trees.

Reduce temporary branches.

 

[Elmore]

Leave those low branches for now as they help the trunk to develop. Gradually raise the developing crown. Perhaps remove the lower branches before they reach a 1" diameter. A one inch diameter wound should callous over rather nicely.