Which practice is NOT used to help create a dominant leader in young nursery trees?

In the establishment of a dominant leader in young nursery trees, maintaining a clear and strong main stem is crucial for healthy growth and development. Keeping lower temporary branches does not contribute to the formation of a dominant leader; instead, it can compete with the central leader for dominance. This competition can lead to a forked structure or an uneven canopy, which can be detrimental to the overall strength and stability of the tree as it matures.

On the other hand, regular pruning of competing leaders helps to focus the tree's energy on the dominant leader, encouraging it to grow taller and stronger. Training the tree to grow upright ensures that the leader is properly positioned and supported as it develops. Using support stakes as needed provides additional stability to the tree during its formative years, helping it withstand wind and other environmental stresses while it establishes its structure.