The markings on the tress are symbols used by hobos. The x in a circle means 'Good for a handout', and the horizontal line means 'Doubtful'. So probably another way to attract people to Terminus and away from the church. Maybe the priest made them; another sin of his leading people down the wrong path?
With Beth, I'm guessing the hospital has a small group who are experimenting on people. Beth either ends up traumatized, brainwashed, or even lobotomized, thus Daryl saying in preview that she's gone, as in mentally gone.