It really depends on how big is the break. The tree needs a path of cambium growth
to feed the upper branches. A tree with it's trunk completely girdled, that is broken
cambium (the green layer just underneath the bark) all the way around, will not survive.
You can do some fancy 'bridging' grafts to re-establish this path. However,
if there is sufficient continuous cambium left, the tree may still survive. You may have
to do some work splinting the broken area and staking the tree for support. It all depends
on how much work you want to put into it. If the tree is adversely effected, you will begin
to see die off starting at the top of the tree and working it's way down. This could be
quick, or it may take a few seasons to completely go. Young fruit trees typically need
staking until their trunks widen enough, especially grafted dwarf varieties which could
break at the graft. This is especially true if the tree is out in the open in an unprotected
spot. You can try and repair this one, and see what happens.

Sherwin D.

wrote:

I've got a young 4-in-1 plum tree that was blown over a couple of weeks
ago. Thing is, it didn't break completely through and the bark seems
undisturbed on one side. Not only did the tree not die, it's still
growing. Is there any chance that this thing might go on to heal and
live a healthy life, if propped up sturdily enough, or is it a lost
cause? If I had to replace, this would be a good time, except that
nobody seems to be offering these right now.