It’s good to start young. Proper pruning measures taken when a tree is young (generally speaking, 10’ – 20’ tall) can significantly impact its future development.
To help ensure a healthy, structurally sound tree, early signs of problems should be dealt with. These include crossing, crowded or defective limbs as well as competing leaders.
This will allow more space and resources for the remaining tissue to develop into a well-formed, healthy specimen.