Tree disease help

I have a couple diseases going on in the same tree - one is dark spots on the leaves, which I assume is fungal, and the other consists of outgrowths that look similar to bark that project out from the limbs. Can't find the second one online. Anyone know exactly what these are and how to treat them (if they require treatment)? I've read that some fungal infections are purely cosmetic and won't kill the tree, thus not requiring treatment. But this year I have several small trees 2-3 feet high that are growing out from the roots of the big tree, and I'd like to continue growing them. They were doing fine, but 3 of the 5 have the spots and two have the bark-like projections already, and a couple of those are starting to die. The two right next to them that lack any problems are growing very well, so I'm assuming that the diseases are what's killing the others. Any help is appreciated.