This year we had unexpectedly warm weather, followed by a sudden freeze. This impacted many of our plants that were beginning to leaf out early. It also damaged blooms on fruit trees. It is possible that this sudden frost after warm temperatures is what caused this stunting. If your tree is otherwise healthy I would wait a few weeks and see if the stunted leaves and damage begin growing out. If the stunted leaves persist, I would recommend contacting an arborist to come out and inspect your tree. Small leaves can sometimes be caused by other issues such as disease, drought, or damage. You can find an arborist at the following site.

treesaregood.org