Legal Question in Real Estate Law in Illinois

Oh my. The "general rule" is that your trees are encroaching and your neighbor would be w/in his rights to have you trim them back to the property line and to trim them back himself if you refuse to do so and if it interferes w/ his reasonable use of his property, as long as he doesn't kill them. But you have some unique facts (this is agricultural land so what is a reasonable use is at issue, and these trees were planted and not just a natural stand meaning even your dad should have known at some point they would overgrow the property line) and based on what appears to be current research materials, Illinois law on this subject with these additional facts isn't entirely clear. Then again even if this went "to court" a trial judge may cut through the facts and apply the general rule and you'd be stuck with an appeal. So from a practical standpoint, while the "tree cutter" may be right, is he a certified arborist? If not the arborist may be able to help find a way to trim them bit by bit so they're not damaged as such although it may take longer. If you leave it to your neighbor he might kill them as the cutter suggests, and if you're not quick enough to run to court to stop him, then the trees your dad planted.....are dead. Clearly you care but the question is how much..... Illinois law does not seem to support the idea of adverse possession but then that is where there is natural growth and this is not. It may also be worthwhile for you to check w/ a local attorney about the possibility of going to court for a declaration of rights based on a comprehensive search of case law; again the question is how much you want to spend to make sure what you have to do..... Hope this provides some direction. There may be other facts mitigating for or against your situation that a complete review of the situation may reveal, and this forum is not equipped to do so.