my neighbors trees are overhanging my house and ruining my roof,causing carpenter ants and pine needles in gutters- any recourse

my neighbor has very large pine trees lining his property. They have gotten so big that they are hanging on my roof, causing my roof to curl on the corners. My gutters are clogged with pine needles- I have gotten carpenter ants that I have to pay someone to spray for and have asked many times for them to be removed and he will not. He now does not live there, but his children are caring for his home and we have also asked them to have them cut back. What is our recourse at this time?