Hello,
Sorry, I know the color didn't come through very well on the pictures. In person the majority of the trunk is still bright green, even without scratching.
I performed my prune a couple days ago. I was hoping to only take off the right limb and the top of the left limb. But when I turned the tree around, I saw that in the previous day or so the black patch from the right limb had spread onto the main trunk.
Ended up cutting down to a stump and paste sealing. The remaining trunk is still bright green.
I'm not hopeful, but I might as well just wait and see.