Your yard looks very similar to mine. Neighbor to my east has several trees that always grow over my fence, shading the grass, scraping on my storage shed, growing through my fence, leaning against my fence. When they need trimming, I trim them and never look back. Never had them complain. Several years ago, when the fence needed to be replaced, they were given the opportunity to share in the cost. I never saw a penny from any of my neighbors. My fence, my yard, I'm gonna' maintain them.