Please help if you can. I have a 15-18' Black Alder clump tree in my back yard that has started dropping its leaves for the last 5 days. It never has lost all of its leaves from this but enough fall that I could rake them up if I choose. The leaves appear to be disease free but I have no formal training on tree disease diagnosis. Couple things that may help you help me, this happens every year in the summer, I live in the suburbs of Chicago where it has been an unusually hot and DRY spring with moderate humidity. Over the last week average daily temps have been a high of 90 deg. and a low of 65. This tree is usually irrigated by rainfall only although this year I have watered it by hand to see if it may make a difference. Any suggestions that might help minimize this leaf drop would be great. This tree is a great shade tree for my patio and pool deck and want to keep it that way. I will post pictures if needed but to me the pictures will look like a ordinarily healthy tree in the fall.