Hello Bill ,Allen & All,
I agree with most of the things Bill has said up to a point. The main
reason most beekeepers wrap hives is so the bees can handle rapid drops in
temperature.  I added this important point back in the last discussion.  We
all have seen hives dead because the bees couldn't return to the cluster
fast enough.  Clusters split and bees cought in feeders.  Wraps are usually
done in areas of rapid fast drops in temperatures . In the plains states we
can get a drop of over 40F in a few hours.  Cold may not kill bees but
getting cought away from the cluster and without honey will.  Many bee books
state this fact about wrapping.   Another point about wrapping which can't
be discounted is the warming effect of black tar paper by the sun on a cold
January day. Many beekeepers will say (those that don't or have never
wrapped) this warming effect causes bees to fly into the cold air and die. I
have never seen this happen any more with wrapped than on unwrapped hives.
To irk me my friends will also say my beloved Italians will fly out in the
snow bank and die when their beloved Carniolans won't.   Always differences
of opinions in beekeeping.  Every beekeeper you ask will give a different
answer.  Bill & I agreed on this fact on Bee-L a long time ago.
Wrapping is a lot of work and storage of the materials is a pain.  I
personally do not wrap (now) but wished the hives had been wrapped last
winter.   Richard Adee wraps over 10,000 hives west of me in Kansas each
year.  If wrapping didn't pay I don't believe he would be wrapping.  I have
been getting by without wrapping because we have had very warm winters the
last decade. Hobby beekeepers mainly want a live hive in spring.  Bees
flying in and out of the entrance and they are all smiles. The beekeeper
keeping bees for a living needs a large population of bees in the spring.
Commercial beekeepers polinate Apples in the Midwest first week of April.
Many beekeepers hives other than commercial beekeepers at this time have got
a cluster about the size of a softball ( basketball????).  Hardly enough to
get a polination fee for.
I do agree with my friend Bill about the key to wintering begains the fall
before. Hives not properly prepaired the fall before stand a poor chance of
surviving.
Bob