We had a late frost on Friday, and I just discovered that some young trees that are totally adapted to our climate here are sensitive to frost. We had red oaks, black locust, and some other nut trees that have burned leaves now. Some of the oaks were just putting out their first leaves as seedlings. On the other hand the apple trees didn't seem to be affected.
Temperate trees which leaf out with frost-tender foliage usually have some lower buds in reserve and are able to leaf out a second time. In fact most trees do this.....it enables them to recover from a defoliation by caterpillars or whatever during the growing season.