Destructive neighbor

I have owned my home for 24 years. I am at the end of a street and one house meeting up to me on left side of house. The original owners of my house planted many trees around the perimeter of my property. The trees on the side of this neighbor were great in the years needing the shade for swing sets, picnic tables, etc. Through the years they have constantly cut my trees without speaking to me and without knowledge if what they were doing harmed the trees. A couple of winters ago one of these trees fell from the soil getting soaked from heavy rains. From constantly hacking on one side of the tree, it had died and fell. Today, I came home to find all my trees hacked up and some of these trees are large and old. There were large tree parts all along his property along with a lift truck cutting on my large tree in the back yard.This man said nothing to me. I am sure that these trees are going to die also. Through the years my children have been threatened and my pets have disappeared. This person thinks he can do what is wants. Any rights here.

You'll need an updated survey (which can run anywhere from $400-$900 depending on your location) and if it can be shown that the trees were completely located within your property lines, your neighbors could possibly be held liable for damages/replacement costs. Depending on where you live, some cities offer mediation programs for boundary disputes through their zoning office. It's not very likely you can successfully resolve this without a current survey from a licensed land surveyor unless of course, your neighbor is willing to negotiate. (Your city or county deeds office will have an existing survey on hand also, but the one on record is probably outdated and may not reflect any changes through the years.)
Once you have the survey and a few free replacement estimates from reputable licensed landscapers in your area, you'll need to decide for yourself whether to follow up in small claims court or to contact a real estate attorney. Depending on the size and amount of trees that were removed from within your property (if that is indeed the case,) this dispute could turn out quite costly for both you and your neighbor.
Good luck. Any chance of negotiating a tall fence with the neighbor?