Tree Leaves Have Black Spots?

You don't say the type of tree, or much about the black spots. Your 'tree' could be a tall rose bush, or an actual tree-black spot on different types of plants have different causes and treatments.

The best thing would be to take a sample to your local extension service office for identification. That way you would be sure of the disease and the proper treatment.

Google your local university name plus the words extension service, or look in the government pages of your local phone book under Extension Service to find a website, address, and phone number so you can talk to an agent.

The services available through your local extension office are mostly free although some services like soil testing can have a low cost attached.