Greetings,
We had a row of Chinese Chestnuts along our fence line and, at the age of 60, 11 of 12 died. I have written to a number of web sites and colleges and everyone says it had to be something in the environment. But its unlikely anything was sprayed there and I can't think of a thing that changed. Actually the only thing that changed was a planting of Christmas trees in the field but they were way outside the drip line and the "experts" tell me that this wouldn't do it.
Since then I've replanted and, despite a few losses along the way, I think I have them going pretty well. They are still small so I put little wire fences around them to discourage deer but the leaves are still eaten by bugs a bit.
In any case, I think they are one of the great pleasures of country life. Best of luck with yours.
Thanks,
Rod