White substance on tree

(Question)

Hi there,
We live in London Ontario in an area close to an old gravel pit on top of a hill so we have good drainage. Our Norway Maple has started to get some white spots and I am wondering if it is fungus. Some Maples on the neighbourhood Boulevard have been dying from fungus.
The leaves seem ok it is the trunk that has spots.
Hopefully it is just some kind of lichen or missy type growth. So far it is just one side of the tree that has the spots.
The tree was fine last fall but the previous year the leaves had black spots on them when they fell.
Please advise as to what you think it is and whether there is anything that can be done.
Thanks for your time and help

(Answer)

Hello and thank you for your inquiry.

Your Norway Maple (Acer platanoides) is certainly a lovely mature specimen.  It is difficult to see what this growth looks like close-up, as the photo is too distant for accurate analysis.  Our suggestion when dealing with such large trees is to consult a certified arborist, access to which can be obtained through Landscape Ontario.

https://landscapeontario.com/

If the growth is lichen, we have attached an article below for your reference, and there is no cause for alarm.

https://www.canr.msu.edu/news/liking_lichens_in_the_landscape