They're small now and have a great deal of growth ahead of them so the shape doesn't matter. More important than what the tops look like, what do the roots look like? Did you plant these trees? If not, take a look to see if they were planted too deep in the ground. For a while after being planted, if the trees can be wobbled it means the roots are probably still in a tight ball from the pot, so the trees won't grow well or quickly.
Take a look through the Library of Organic Information on the home page for tree planting tips.
Here is one to start with.