Generally there is little specific pruning required of most trees other than to remove dead, diseased and crossing branches and unwanted growths. Always remove stems that are growing over or swamping other planting to allow all plants space to grow in.
If branches become overcrowded they will need to be thinned out, removing approximately one third of all growth. It is advisable to remove unwanted growth back to the point from which it arises on the main stem, rather than shortening shoots back.
Other than this they only need to be pruned cosmetically to suit the size and shape of their situation.