Reddit reviews Winter Tree Finder: A Manual for Identifying Deciduous Trees in Winter (Eastern US) (Nature Study Guides)
We found 2 Reddit comments about Winter Tree Finder: A Manual for Identifying Deciduous Trees in Winter (Eastern US) (Nature Study Guides). Here are the top ones, ranked by their Reddit score.
I don't know for sure, but I would guess those are going to be flowers, not leaves. I would bet the leaves are coming later.
Edit: I have and like this little guide to leafless trees; maybe it could help you with yours too! https://www.amazon.com/Winter-Tree-Finder-Identifying-Deciduous/dp/0912550031
Here is an excellent field tree ID book for the Eastern US by leaves. Here is another tree ID book for the Pacific Coast. Here is a tree ID book for the Eastern US during winter.