i wrote a song called hunting the public lands blues ive been there many times before. the only advice i can give is to use your flashlite and flash that thing back at him like a disco show!. most will move on but some dont care. one time i got down from my tree and told a guy who set up 50 yards from me that i like to think were not fishing opening day of trout season in the river shoulder to shoulder but he didnt care. most seem to think thats a far enough distance but i think 100 yards is more fair. theres plenty of woods to hunt. most of my hunting buddies would have gave the person hell who showed up and screwed up the hunting being that close. they would yell or even fire off shots if they had to just to screw up that guys hunting. i could never be that way and im glad you didnt do anything in that manner. when something like this happens my softy side kicks in and im always thinking that it could be an old timer , young kid, or first timer that just dont understand the big picture. hang in there. remember up in the tree you have a better chance to shoot the deer first anyway. i would just hunt the first couple hours then get down and just explain things to the other hunter. they even might learn something