It will be helpful if you upload some more images of both upper and lower leaf surfaces. Are the black spots superficial? If yes, it could be sooty mold. Also, did you notice any insect on the tree especially sucking insects (like hoppers, scale etc.)? Usually sooty mold develops on honey dew (sugary substance) excreted by sucking insects.
Posted by: Dr. Ravishankar Narayana
Posted: November 17, 2017