I'll suggest that both trees, especially the street tree, are running short of water.

The two pictures of stuff on the trunk(s) show lichen of several different colors. Not a problem. Lichens tend to grow on trees that are growing slowly.

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My neighbor's trees look almost identical to yours. This is what she told me: the green stuff on the trunk is a fungus and not harmful but grows on weakened trees and can be sprayed with fungicide in early spring to prevent it from growing. Her trees were planted too deep and the trunk is girdled and the roots are bound. I have since found out that the main roots on the tree should be level with the top of the soil - so right where the trunk starts to widen is where the roots start to come out. An arborist came out last year and aerated the roots with some tool they have, trimmed off some of the dead twigs and branches on top and told her to water, water, water. (BTW, I don't think she waters frequently enough or thoroughly enough) The trees look better this year but they aren't really what I would call healthy. These are things I've been told. I have no idea if the arborists are pulling her leg or taking her for a ride but again, her trees look just like yours.

stl wrote:
"This is what she told me: the green stuff on the trunk is a fungus and not harmful but grows on weakened trees and can be sprayed with fungicide "

Not so.

As was said, it's lichen. Not a disease. Not a problem. Fungicide won't get rid of it.

mine is alive on the bottom but dying on the top. should i prune all the way back or top . did not give leaf last year

I looked at Jim's photos from 2007 and they look exactly like what I have with maples in my backyard. Did anyone determine what the problem was. Jim, how are the maples now>