What are those?

What is the problem?
chlorosis on red maple
                                                                   Chlorosis on red maple from unavailable manganese

What are the symptoms? What common ornamental trees are particularly susceptible? How can I solve the problem? Where can I get more information?

Koenig, Rich, and Mike Kuhns.  1996.  "Control of Iron Chlorosis in Ornamental and Crop Plants."  Utah State University Extension.  For other information, advice and help on this topic, call offices of your State Urban Forestry Coordinator or University Extension service, or visit urban forestry web sites.