Well, I too had an ornamental cherry die (Hally Jolivette). It was beautiful this spring, blossomed incredibly and the next week ALL the leaves were brown, crisp and shriveled. I am stumped and sad.

You can bet your life it's last year's drought. Last year, the arborists were saying the longterm effects of a drought like 2005 would be pretty terrible, and we're beginning to see problems here, too. One of our Austrian pines looks terrible, in spite of my best efforts to keep it watered last year. The thing that really scares me is that stressed trees invite disease organisms, and the Chicago area is FULL of stressed trees.