Genetically improved trees are one of many elements to consider when selecting a quality tree. Your next consideration should be how the nurseries plant, cultivate and maintain their trees. This is important because a street tree will be resident of the nursery for many years and requires a lot of specialized treatment to prepare it for the street. Trimming gives the crown a strong structure and raises the branching to a proper height up the trunk. Branches help the tree put on caliper growth, but if the tree is not trimmed when young, the later pruning cut can cause considerable damage.
Roots require pruning so a fibrous and compact system is produced.
How a tree is cultivated makes a difference in its ability to survive and stay healthy. If a tree isn't properly root pruned, for example, most of the roots needed for survival will be lost when it is transplanted. The tree may survive, but will grow slowly and require a great deal of care. There is a long list of things that need to be done by the nursery to prepare a tree for street planting. The buyer needs to insist on quality and be sure the bidding process recognizes differences in quality.