David Johansen wrote:
We live in Tucson, AZ and we planted dwarf lemon, orange, and kumquat
trees in our backyard this past June and the orange tree appears to be
doing great, but the the lemon and kumquat have lost all of their
leaves and the branches look brown and shriveled.

So is the tree dead and need to be replaced in the spring? Or will it
come back?

Thanks,
Dave

Test the branches by bending them between your fingers, any living tissue
will be below dead wood. You are looking to find the living tissue which
will be flexible. You may also see a line where on the upper side the wood
is dull, brown and shrunken and on the lower side fuller with some green,
this is the line between alive and dead. Any live wood might shoot again,
you will probably have to wait until the growing season starts to find out.
If there is no live wood they are finished. If the only live wood is below
the bud union the scion is dead. If the rootstock shoots again it will not
be the desired cultivar that will bear good fruit. Before replacing them it
would be good to find out why they died.

David