That sucks. Well.........maybe you can put up an electric fence???? Let those bratty kids climb on that. HAHAHAHAHA!!!
Show ur neighbor a map of where the property lines begin and end..tell him that he needs to be more considerate of your property, whether its the fence in the ground or the limbs on the trees. Next time he acts like a dumbass and messes with your stuff...give him a dose of his own medicine!! Put a glass bottle behind the tires of his car or let your boys just throw baseballs at his windows..one right after the other!
I'm a lawyer. The law says he can cut branches from your trees that grow over/into his property but he can't come onto your property without your permission and he can't cut trees that are on your property.
He and his wife sound like idiots. I would call letting three-year-olds set off fireworks child endangerment. You could report them to Child Protective Services, or DYFS or whatever they call it in your state. The same goes for letting a small child wander with no adult supervision: it's neglect.
I don't think you can expect much from him. If he is dumping on your property you can call the police. Illegal dumping carries a fine. If he claims to be "storing" items on your property without your permission, well, you know what they say about possession being none-tenths of the law. That stuff is YOURS if it's on your land. Keep it. Dump it. Sell it. Whatever.
Sorry. I meant possession is nine-tenths of the law.
Keep a record of the stupid crap he does and take pictures. You may need it someday if you choose to prosecute him.
Good luck.
The next time he messes with you, stand outside in your yard with a shotgun at your hip for a half hour or so.
That'll rattle him.