Let me add more info: I buried the fig with leaves up to waist height. The tree bark were chewed off /partial off all the way up to that height. Does vole, mouse or pillbug go up that high to chew the bark?
You should carefully excavate and see if there is still bark on the crown. If there is still bark it should regrow fine, you can leave it exposed to help buds grow sooner.
If they ate the crown, all you could do to salvage it is graft onto some nice fat roots. It is kind of awkward to graft in a hole, but less work than replanting and watering to get a new plant established.
It could be mice or voles, there is probably a nest in the leaves. I use snap traps around the base of the trunks, or for voles I set them in their trails and tunnel entrances.
@Kellogg_Hill_Farms I took and posted more pictures. They do have tooth marks. I am reluctant to use poison because I have a cat and there are also some other cats come around. I don’t want them accidentally pick up a poisoned dead mouse or vole.
@hoosierbanana I will explore the ground and see if there is anything (crown or fat root) there. As for setting trap, is one trap enough? I never have to deal with voles before(maybe they are always there, I just didn’t know), hate to think I have to start now.
Cats are predators, not scavengers. They enjoy the kill, much more than the meal. If you are concerned about them getting poisoned, choose a poison that has low chance of passing onto 2nd or 3rd consumers, such as an anticoagulant.