Posted: 04/07/2013 at 04:40
I think I'd call a professional tree removal service to get those trunks out. Also I've rototilled my garden and had I known, wouldn't have bothered in many areas. The roots wind around the tiller and then requires hours to try to get the mess untangled from the blades. Also this previous owner had underground sprinklers and extension cords I didn't know about! The hoses were rotting anyhow, but it was a disaster.
That fence looks like it should be replaced. Trees should never be planted right on a property line or right beside a structure!
Anyhow, one thought I have is that you get the roots out as best as you can and then consider adding several inches of topsoil before laying grass; raise the entire lawn so the roots are burried.