My sugar maple looked OK last fall, but this spring I saw that the top 15 feet (out of about 35 feet) of the tree- the leader- was dead. I cut it off, thought maybe it was verticillium wilt, but there was no brown ring in the cut part... Could it be our arid summers, getting more arid? I know it isn't a native tree. The tree looked pretty good this summer, but it is very dry again around here. (In fact my native vine maple is all brown this fall, without the usual fall color.)

Ansel - you sound like you know a little bit about horticulture! I am going to refer you to your local Master Gardener group, in King County. They have an email clinic so you can direct your question to ask-a-mastergardener@live.com or to know when their in person clinics are you can see their webpage at https://extension.wsu.edu/king/ask-a-master-gardener/ . Good luck!