Location: West Branch, IA A long row of approximately 50 arborvitae running E-W on south side of property in a subdivision with 3-5 acres lots. For years these trees did well (there is a row on the north side that still looks fine.) Planted about 10' behind the arborvitae is a row of some type of willow, now about 30-35' tall and causing shade on arborvitae in spring, summer and fall. Arborvitae are mulched each year. Distress has started at low end of property and is gradually moving up the slope and consuming more trees as it does so. I can send samples, but I have a sense that it is not a disease, but climate related in some way, Attached are a few pictures, hoping you can help.