maple trunk spots
Thank you for the question. It's hard to make a definite diagnosis from a photo but it looks like your tree may have some lichen growing on the trunk and branches. It requires no management and isn't harmful to the tree but you may want to examine the tree very closely to see if there is any thinning of the canopy or branch system that would allow more light, moisture and nutrients through to the trunk that support the growth of the lichen. Read more about it here:
Thank you for contacting Extension.