First let me say I am not a tree guy so please talk down to me with your suggestions so I may understand Yesterday, I was doing some routine maintenance to what I am told is a Black Alder clump tree in my back yard. I was trimming sucker branches from its base (they are seen in the attached pictures) and while doing so I discovered what appears to be insect damage at the base of two of the trunks. No insects seen at the time of the pictures. The affected areas also have its bark is peeling off in that area. I also see some defined lines in the trunk where the bark had fallen off. That picture is poor but you can still see what they look like. I have mixed up a batch of Tempo to spray into and around the affected areas but wanted to get the advise from those who deal with this daily. After treating the affected areas what should I do to protect / save that tree from the possibly of dying or loosing affected limbs. That tree provides perfect shade from the setting sun on my patio and living room.