What is wrong with the leaves on my maple tree?
I just noticed raised spots/growths on some of my maple tree leaves. They look like tiny shotgun lead BB in the smallest size offered (#9). What is this, and is my tree's life at risk? The tree is about 50 feet tall and really thick and it has full branches and leaf foliage. It looks full and healthy, but the leaves are definitely smaller this year.
Washington County Minnesota maple tree galls
These are maple galls. They are caused by insect feeding early on in leaf development and harmless. There is no action required on your part. For more information about galls, here is an Extension publication: http://www.extension.umn.edu/garden/insects/find/insect-and-mite-galls/