When harvests have been completed, remove all fruit from the Deciduous Trees and rake up all; leaves, fallen fruit, and weeds. Send all the orchard waste for composting.
Many pests "over-winter" in the fallen fruit and fruit left on the trees. The fruit left on the trees are called "mummies." It's best to have these professionally composed, so that the usually higher temperatures obtained can kill all of the pest larvae, bacteria and fungi. If the tree has been very healthy, without a lot of disease on the leaves, then composting leaves in the garden is fine. If not, put the leaves in with the fruit for the community composting operation.
Accumulated leaves and weeds are a favored spot for pests to spend the winter, in their own state of dormancy. In the Spring they would be ready for another life cycle..... unless of course they've been composted !!
If you have composted leaves or other clean mulch, this would be a good time to spread a fresh layer under the tree.
OK - While you're under the tree spreading the mulch (remember to keep it away from the trunk), it's a good time to remove any "suckers" that appeared since your last tree care. These will be sprouts and shoots that arise from below the graft union, or coming up directly from the roots. Don't be fooled by their healthy and vigorous appearance. These just steal nourishment from the tree, we're not interested in growing more root stock. You can also renew the "Tanglefoot" (your anti-ant trap!). On the young trees you can renew the trunk paint (white water based latex paint, mixed with an equal amount of water) right down to the top-most roots. This will protect against sun burn and ground-level insect Borers.