Frank asks:
> Can the bees maintain a survivable brood nest
> temperature in a ventilated hive with
> an inside temperature of -20 degrees C?

This is EXACTLY what is being written about screened bottom boards.  It is
commonly accepted amongst researchers (and even beekeepers are getting it)
that good hive ventillation is preferable to air-tight hives that have been
the winter's goal for previous decades!  This is not to say that wide open,
drafty hives will become the norm, you do not want gaping holes in your hive
bodies, but you want good ventillation.

What has been discovered (rediscovered?) is that a hive that allows good air
flow so that freezing cold, fresh air can come into the hive to replace the
moist, damp air produced by the bees' metabolic functions is ideal.  A
screened nottom board and screened entrances will allow fresh air to come
into the hive as the relatively warm, moist air rises out of the hive
through the upper entrance.  This turn over of fresh air is GOOD for your
bees.

Bees DO NOT/NEVER DID warm the insides of a hive, they only warm the volume
of their winter cluster.  Winter raised brood is raised within the interior
of the winter cluster.

Cold DOES NOT/NEVER DID kill bees.  Prolonged confinement in a cold damp
environment is the main cause of winter kill in a beehive.

When I was in my "newbie" years I ended up with a hive of mean nasty bees,
which I figured were better off DEAD!  To accomplish this goal I purposely
left the cover off the hive during February and March.  The bees survived!
Now THAT'S ventillation!

Aaron Morris - thinking good ventillation!