Well, you left a big stub that is now dying and has lichens on it. NEVER leave a stub on a tree. You must cut that stub off near the trunk, making a cut as close to vertical as possible. but not so close that you cut into the branch collar ( a bulge where the limb meets the trunk).

Natural break down of dead wood by fungus. Correct removal necessary.

FWIW: You should remove that rope from the other branch in the picture or there will be another dead branch in your future.

I'd say fungus rather than lichen too.

Sound like I need to cut it off either way. The rope is is coated braided steel and part of a dog run that's been there for some time...it's looped around the limb.

I don't know if it will recover at this point or not though I think it would. I'd cut the cable if there isn't a connector to unhook. Even a hacksaw would work if you don't have a bolt cutter. The little bit you'd hurt the bark wouldn't matter.

What harm is the cable doing...it's been our dog run for a while now?

About the dog run cable... I actually have a clothesline strung between two trees. I loosen it every time I see it's getting snug, maybe once every year or two. Not an expert, but I have seen a few trees with wire wrapped around, where the tree swelled around it as it grew. Sometimes didn't completely girdle and kill the branch, but seemed to have problems with bugs, lichens and rotting as it was a weaker spot. I'd loosen it every year or two, or slide it up so it's not tight to keep the bark strong and healthy.

"What harm is the cable doing...it's been our dog run for a while now?"

The cable is sinking/cutting into the branch, because the branch is swelling with growth and the cable is not stretching or expanding. This will continue causing a weak spot in the branch and either kill the branch out right or other problems will come in that take advantage of a weakened part of the tree, as mentioned in the above post. That's if the limb doesn't first break off in a strong wind.

Makes sense... I will lossen if necessary..tx!

Ok, so how do I cut this...look how it merges into a major limb.

looking from other side:

Anyone?

Cutting large intersecting branches is not the most fun. Here's a quick guide that talks about the branch collar. Your branch collar may be a little less defined as to where the cut should be made because of that intersection. But the branch you are cutting is already dead, so you want to cut up to where the dead wood ends and green tree starts without cutting into the live bark and wood. You'll have to look carefully to determine where the cut has to be made. It's hard to tell by looking at the picture but it looks to be where I marked the picture following. Be careful not to cut into the adjacent branch. You can always take a little more than add back on so cut a little long if in doubt and then take more if necessary.

I can get in there..was not sure if I should cut it horizontal as suggested or vertical...TX

As square with the branch being cut as possible.

ok, I looked last night and can get in there and make a horizontal cut instead of vertical...it does not matter that the cut will be facing up...more exposed to rain and such....probably a stupid question...