I always have difficulty with this as well. So far as I know, a lot depends on the exact type of tree or shrub. You may get the answer if you Google the tree/shrub name and look it on some gardening/botanical site(s)
if they are decidious trees, ie that is they always loose all their leaves in Winter then in that case it is best not to move them until all the leaves are gone.
If they are evergreens ie they always have leaves in winter then I think it best to wait until the spring but you could probably do it now also.
As they were only planted last year it should be no bother moving them but try to keep as much of the root ball as you can together and also water them well preferrable the day before moving them.
Have the new location ready first so the roots won't dry out lying around and only water the new hole AFTER you have transplanted the trees and heeled them in.
now will be ok to transplant them but leave a good ball of soil around the roots and mix a bit of compost if you have availability of it and what distance did you plant them at if the tree type will grow more than 15 feet tall and spread wide leave at least ten paces between each tree.