If you want to plant trees, unfenced, you need to provide a LOT of lead poisoning to the local deer herd.
A few years ago, I went back to a place I hunted back in the 70's. It was full of deer then and you could see forver in those woods. The ridge top was white pines with some ehmlocks on the edge of the ridge and down over the north side. Not a seedling survived, ever.
Went back after the first HR of the 80's and 90's, might have been 2000 or 2001, and there were white pines and hemlocks maybe 3-4 ft tall on that ridge top!
Just took some lead poisoning to allow those seedlings to take off.