Question:
I was at a someones home that has many pomegranate trees. They gave me permission to take what I wanted . Is there a halacha against picking them and eating them?
Answer:
One is not allowed to destroy a fruit tree for no reason but there is no problem to pick fruit from a tree for human consumption. (If the tree is in Israel Trumos and Maasros have to be separated from the fruit).
Sources:
Devorim 20:19-20, Y:D 116 Pischey Teshuvah 6