This past winter was the second winter I stored trees in my detached unheated garage. two winters ago it was very mild and not a great test. Everything survived with no damage. This past winter I stored a lot more trees of all sizes. It was a little colder overall and we had decent cold snap. A few times I turned on heaters in the garage to bring the temps up a bit short term, which maybe caused issues, I don't know... I re-potted, up-potted and root pruned all my trees over the past few weeks and put them outside. What I am seeing now is that my larger trees have some significant die-back and I am wondering if some are going to make it. Some are budding and look like they will make it.  What is interesting to me is that the small trees are all fine. Most are breaking bud or swelling. They were all pretty much in the same place. I scratched a little bark and it looks alive, but but I'm not seeing good signs on the outside. I am also seeing some splits in the wood around branches on a few trees. I know this topic came up a few weeks ago and maybe I watered to much over the winter.
I know people store trees with no issues in similar situations and colder climates. If these trees come back I want to make sure this doesn't happen and the small trees I hope will be larger this year I don't want to set back.
   What I think happened is that the larger trees that seem to have the issues are trees that rooted into the ground last year early on and I could not get them up until fall when I just cut the roots. These trees ended up getting stuck in pretty small pots relative to the sizes they ended up growing to because they got roots in the ground. When I cut them up  I stored them in these pots. When I repotted them they really did not have a lot or root mass. I tried not to take off to much. Could that be the issue? Maybe they didn't have enough root mass to store energy or now they don't have enough to sustain the top growth. When I pruned the roots they seemed to be a live. It has really only been the past few weeks that I can see what branches are dead.

Are the cracks you mention more like bursts ?
If they were kept warm for an extended period causing the fluids to start moving up the branches then went below freezing then you could get those burst sections .
My garage never goes below freezing , I watered 3 times in total ( light watering ) during the winter and have about 100 plants , they all survived with no dieback at all .
How cold did it get in there ?

John

I guess it could be a burst. The branch still looks alive. It just has a clean crack in it like you tried to saw it off and stopped half way. It is connected to the trunk still. It probably got in the mid 20s in there atleast for a little while. If never warmed up enough for anything to wake up over the winter.

Did you prune the larger trees?
I also only watered lightly 3 times all winter.
I kept 89 of my larger figs in an unheated garage in z 7 and they are all doing very well. It does look like I lost some of my perennial flowers though as I think they could have used more water.
One winter I had just moved (4 years ago) and I did not have a very good place to store my figs yet. It got too warm in the storage space at times that winter and the plants got confused and sent energy top side. This created a number of problems that resulted in the death of a couple dozen trees. I had taken backup cuttings when I saw this happening but you can't get back time and growth.
How warm did the heaters get the figs and did they show any signs of breaking dormancy?
How cold did it get in your garage?

I didn't really prune them. I took a few cuttings here and there. They had green growth which I didn't think would make it, but it looks like more then I though. It was low 30s high 20s probably in the dead of winter. A few times when it got really cold I heated it to high 30s or 40 in the evening hoping it would stay warmer at night when it got really cold hoping it would not get t cold overnight. The thing is I had small 1st year trees with thin branches right next to them with no damage. Nothing ever broke dormancy in there. I Warner's maybe 3-4 times over te winter, but many it was to much each time.

You may lose some top growth and you may need to airlayer or root the damaged branches but your trees should be fine.  They have to produce new growth to get the better, main crop figs so you won't have that much of a set back.  The others have answered your questions but I want to give you encouragement you should do ok.  Also remember that when you root prune you should prune the top also.  If you want to see a comeback fig, look at the first photo here.

Thanks guys.

The temps you heated to should be fine , may garage was in the high 40's a lot of the time , and no problems .
Bob is most likely correct , just give them some time , they will come back .

John

Some were in 5g some in 7g. They were second year trees last year. They did not fruit heavily. I didn't bury the pots. They just rooting through the bottom holes or sides. They were between about 3 feet at the beginning of the summer.