First: get the property surveyed again and make sure it is accurate. If it too expensive, you could barter a detail in exchange, or for a reduced price.
Check the communities fence oridnances as to placement on property. Good fences make good neighbors... and to tick him off, put the good looking side facing your property!
I noticed communal mailboxes in the pics.. does he have to step onto your porperty to get his mail? If this is the case, tell him he can't step onto your property, and if he does, you will contact the local constabulary to file a complaint.
If he continues to trespass, I would make up a letter using Microsoft Word on some very high grade paper , make up the name of a law firm and inform him that you will bring him to court if he steps onto your property again, even to get his mail...
I would check with town hall in reference to the site plans for the complex.. they would or should be on file in the Building Department and the Assesors Office. You may have a recourse going after the builder who misrepresented the property lines if you were the inital owner.
If in fact the property is his, he should be paying more in taxes for the additional property.. even if it is just $5 dollars more, it is a victory.
If his trees do in fact go over the line you can trim them back. If you enjoy the shade, just blow "his leaves" back onto "his" property... after all, they do belong to him...
