Or would it be possible to prune them back to a manageable size? I don't have much experience with arbs, but it seems I see them in tidy little rows quite often. Might be worth having one of those tree arborist people come out and give you a bid on managing their size. My brother-in-law bought a house with a nice mature row of arbs between his back fence and a rather messy farmer which he promptly cut down, and has spent time/dollars trying to rescreen. I can only shake my head...
