I would definitely find out who actually owns the properties and where they stand on biking.
We've got some extremely arrogant so-called 'environmentalists' in my area. They are so full of themselves, they believe they have the right to make the rules on other people's property and don't hesitiate to claim it as their own. They have no problem at all telling you they make the rules on property they have no claim to whatsoever, because they've deluded themselves into thinking they own the woods in it's entirety. Sounds like you've met a guy just like that.
Get your facts in a row first - go to town hall and get a plan showing property lines and owners. If he actually does own any of the land (which I wouldn't necessarily believe just on his word), is there a way you can re-route the trail so it doesn't cross his property? We've had lots of luck with private property owners allowing us to pass through. If he doesn't own any of the land and the people that do are cool with biking, have fun setting him straight. Then get ready for the booby-traps and vandalism, cuz that's how those people operate. I'm installing game cameras this week to catch them in the act. Should be a nice surprise when they find out they got caught on film.
Slapheadmofo Leisure Team
Sunday River Bike Park