"a_plutonium" schreef
The rabbits ate all the way around and about a band width of my hand.

***
I should read more carefully. If the cambium has indeed been removed over
such a width there is not much chance of the tree itself repairing the
cambium.

The green leaves themselves don't mean much, as the sap stream upwards goes
through the wood, presumably not eaten into by the rabbits, so that the
leaves do get water. The stream downwards carrying sugar from the leaves to
the roots goes through the bark, which is gone. The roots will be the first
to die (this may take a year or more). Only then the rest of the tree will
die as well.

Trees do have capability to repair the cambium, but this will depend upon
the width to be repaired. A hand's width sounds like a lot.
PvR