Green sounds promising.

Iirc, I've seen some fact sheets put out by extension offices stating to wait when removing freeze damage. See what comes back.

The greenish material is the cambium layer. If it is green, then it is still alive (now). However, I have noticed green cambium on some sickly trees that ended up dead.

Nik, is it really necessary to remove the dead branches? I have read this many times but does it really matter? By the way, I , too would remove the dead branches but mostly for aesthetic reasons.

Dead branches and twigs on live ones call for infections and boring insect attacks. The same is true for live branches with bark wounds.

Thanks Nick and everybody. I can’t imagine getting any new growth out of those sections, but I wasn’t sure if they still serve some purpose for the tree, such as an energy reserve.

Several of the trees have obviously died back to the rootstock which is sending out new shoots. Given that they have established root systems, is it a good idea to try grafting? I haven’t really thought of doing this before, as largish grafted citrus are very cheap here.

A very good opportunity to learn how to graft. But wait for the thicker branches which may be alive. A graft on an established stock grows really fast if compatible. In commercial orchards when they want to change varieties they usually just decapitate the scions off and graft on the existing stocks. This also avoids any issues with specific replant disease.