kill the offender.
then take your friends to his house.
cut down all his trees.
Plant a homstead on his border and start digging
kill him every time he walks out of his house.
i mean jeeze...send one of yours to the hospital send to of theirs to the morgue.
i'm sorry, but at some point you have to stick up for yourself..whether that means knowing your neighbors to help fight against interlopers, huddling up to someone bigger and stronger that will benevolently protect you, hiring some mercs, or just summoning up the intestinal fortitude to go carve someone up yourself.