[jyl]

Your neighbors are *******s.

I would do this.

1. Find lawyer. Have lawyer write letter warning neighbors not to cut your trees or trespass on your property, or to cause others to do so. Have letter delivered to neighbors via certified mail, return receipt requested. Or better yet via process server. This will cost, say, $600. Well worth it.

2. Visit police. Explain neighbor stated intent to trespass on your property and cut your trees without your permission. Try to get an incident report, complaint report, whatever you call it. Ideally you want a police officer to go and warn them not to do it.

3. Post trees with large no cutting signs. "Trespassers will be prosecuted". Photograph same.

You see, the problem is that if they do illegally cut your trees, the potential damages you could get from them will not compensate you for the loss. Suppose you get $1,000 a tree. Would you trade $5,000 or so for your privacy and 30-y/o trees? I sure wouldn't. So you need to take every possible step to deter them from doing so, and of maximizing the trouble they will get into if they do..

Being "nice" is a waste of time. "Avoiding conflict" is stupid. These people are *******s and unethical, they get their way by bullying nice folks.

Hard to imagine their mold is actually caused by your trees, I suppose if they are super jerks they could sue you for it, so be it.