So, a friend was looking at my cherry tree, and telling me I need to do some trimming. Apparently late summer is the time to trim a cherry tree, so here we are. He mentioned the "suckers", sticking straight up out of the tree, saying they need to go. I assume he means these: Any advice? I know how to prune a tree, but aside from cutting out dead stuff on some healthy trees, have only ever worked on shaping walnuts and pines. I'm not really sure where to start on this one, particularly since most of those "suckers" are very hard to get at, without harming something else. They're really buried in the tree.