Question

Ash tree   Hello there.
I have a question about my Arizona Ash. It is a younger tree, approximately 10 year old. I Live in Mesa Arizona.
A month or so ago the tree dropped a lot of its leafs. Some just dried up and are still clinging to the branches. About two weeks ago it began getting leaves again, so I figured it would be fine. Now, today I went out and found that the bark is peeling off and under it is a black powdery mold or mildew.(See attached image The tree forks in two, the stronger, or thicker of the two main branches has now lost all the new growth. The second smaller of the two still has some leafs. What do you think is happening, and what can I do to help out this poor tree?

Thank you so very much for your time,
Katie

Answer
Hi Katie:
From your photo and description, this tree may be in trouble. The bark cracks with associated peeling with leaf drop may indicate a terminal situation.  The black sooty growth beneath the bark is probably a fungus that is setting up housekeeping on the dead wood beneath.  This fungus is probably not the cause of the problem, merely an opportunistic organism that is growing on declining wood.  Probably very difficult to determine the factor(s) leading to the stress.  It may be a combination of many things such as an unfavorable environment.  An on-site exam may be helpful to postulate a cause.

Based on your information, I suspect replacement may be an option for you to consider.

Regards
Steve