you didnt give enough info. do you own or lease this 40 acres. if so kick him the hell out. also if you are on public land, you can try to bluuf him off or due what the above mentioned. sit there and tell him to join you. or go find a new spot, it is public land and no one can lay claim to something they dont own.

don't fear the night
fear what hunt's at night
the snakeman