ponderosa pine needles chewed down
The deer have chewed down the ponderosa pine needles to the quick - now very short. Will the trees recover their needles?
If the deer are primary feeding on the needles of the lower branches the trees should be fine. The future of the trees growth, is in the emerging candle (terminal bud), which will produce new needles that will be able to photosynthesize and generate food for the tree. The needle that have been eaten will not regrow and will be shed in the few years.
The drawing below is from the attached Virginia Tech handout. If you are concerned that the deer are causing too much damage you can looking to foliage sprays that provide a foul taste, it will need to be repeated often with the current weather conditions.