What is the difference between the cause and the reason?
I am glad you asked.
THe cause is the action leading to the result. THe reason is the factor that made the cause come into action.
In this case..
This is what you do with deciduous trees once you have the basic structure of the canopy. Once the tree gets too dense for light to enter the inside of the tree, and the growing tips block each other from growing you can trim back and defoliate (except for branches you want to thicken). In a few weeks a second push of growth will come in, doubling the number of growing tips. And buds on the inside will break, increasing the number of branches on the inside.
At the same time I removed the winter wiring and trimmed back all branches that were starting to shoot (Except for a sacrifice branch to thicken the lowest)