Answer: Yellow is the normal fall coloration for this tree. Pruning should be kept to a minimum and can be done in winter or early to mid summer as needed to correct poor structural development or to open the inner reaches of the canopy to sunlight, this latter usually only needed for a more mature specimen. On a young tree, you really shouldn't have much pruning to do at all. The natural shape is quite lovely and will reflect each individual tree's attempt to acclimate itself to its site and reach for the available light. Any resulting irregularity is usually considered to be part of the tree's unique charm.
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