i live in Lower Hudson Valley NY and have enjoyed the Arborvite that border our property since we moved here 5 yrs ago. They are very green and narrow and tall 10 feet or so, Emerald Green variety i believe. Just this past few months I've noticed they are thinning from the bottom up. turning brown and thinning as if dying. All in a uniform way. Up till this point they have been so healthy and beautiful. We have never done anything but let them grow since there were never any problems. I should mention that many homes in the area have the same problem. Actually more advanced so that the bottoms are dead and only tops of the trees are green. It seems so strange does anyone know what is happening and how to stop it!?