A tree whose leaves were frozen
These two trees standing side by side in Christian County, Kentucky, demonstrate the state of our trees at present.
The tree at right has suffered leaf-dieback from the freeze. The tender new leaves of many trees were killed by cold temperatures recently.
The tree at left had not yet put on its leaves at the time of the freeze. With its new growth still held safely in its buds, it survived the drastic change in weather without any apparent damage.
The vast majority of the trees will survive the setback and put out new leaves soon.
Many of the trees were blooming (maples, ashes, oaks, and others), and since their blossoms were killed, they won't make nuts or fruit this year. This will make it harder for wildlife for the entire next year. The various tree seeds (especially ash and maple) and the acorns and various sorts of wild fruit won't be available.
I am not sure if the hickory trees were affected or not, but if their blossoms froze as well, the squirrel population will definitely be affected.
Related news report: Non-native trees took worst of frost damage
Related post: Tree damage in the late freeze