In my experience, deer will eat anything if they are hungry. Even things that deer supposedly don't eat. My deer never read the book I guess...
Perversely, my deer seem to have a definite preference for new stuff I have planted.
Anyway, now, all the new transplants get a tree tube. Pretty much eliminates the problem, AND the trees grow noticeably faster. It's a couple bucks per tree. If you buy a hundred, they are $2.25 a pop. Even in low numbers, they are 2.65 ea. I use re-rod for the stake.
https://www.treeprotectionsupply.com/tree-tubes/tree-pro/tree-pro-4-ft/
Maybe your deer aren't as hungry as mine...