Linden trees

[cam]

There are several Linden trees in the park adjacent to our property that have hundreds of tiny little reddish tinged spikes on the surface of the leaves. I believe, in the past, I have seen the same sort of disease on Maple tree leaves. What is this disease?

 

[Kneejerk Bombas]

It sounds like Leaf Gall, caused by little bugs making a home. They normally have little impact on the health of the tree because they disrupt only a small percentage of the leaf surface.