I have lived in my house for 12 years. There were 3 aspen trees planted together. As of today the original three all died (not more than 10 years old) and were replaced; subsequently, one of the new aspens died after 3 years. All had the same symptoms. The leaves on one branch would all turn brown and eventually fall off in the summer. This would eventually occur throughout the whole tree and the tree would have to be removed. I replaced one aspen with a crab apple tree and now the largest replaced aspen is showing the same signs - a branch with all leaves turning brown. Picture attached. What is happening to these aspens? Anything I can do other than cut of dead branch with hopes whatever it is doesn't spread. Tom Rasmussen