Dear all, I'm glad I found this forum. I would really need some of you experienced folks here to have a look at these pictures and recommend a course of action. This here is an established approx 50 years old+ sugar maple. One of the main branch seems to have a significant canker in it (refer to pictures). I am not sure if that is a canker caused by rot, animals, or anything else OR an old healing wound caused by the pruning / cracking of an old branch. The problem is that if that particular limb cracks and - God forbid! - falls off, the roof of the house might get the top of that limb. The top of that limb is composed of thin-ish / medium sized branches, but this cause still cause some significant damage nonetheless. It has to be noted that the foliage of that particular branch is perfectly fine and it looks healthy otherwise. What do you guys think? I uploaded four pictures to this thread. Thank you very much.