I've read before that root bound trees in pots will develop smaller leaves and start to decline after a while and that pruning is a way to invigorate the plant and encourage new growth. This seems logical as the roots are confined and unable to grow too much so they can't provide an over abundance of food. However, last year I air layered the top half of a vigorous Shin Deshojo maple that had been growing in a large nursery container for 4 or 5 years. The roots of the parent were not completely rootbound, but close. The top layered half ,as would be expected , had many more dormant buds than the lower half. I have both trees in the same type of soil, located just a few feet apart, and receiving the same water and fertilizer. So, this spring when the two put out new leaves, the air layered top half had numerous leaves that are about 1/4 the size of the parent tree. So, I suspect that the small leaves were a result of the tree having numerous buds but less roots to feed them, and the large leaves were a result of the tree having fewer buds and a quite extensive root system pumping lots of energy into far fewer buds than they are capable of supporting. Does this seem logical, or could it be something else?