Is'nt carbon dioxide more dense than air?
 It would rise slightly from the heat given via bee repiration but would
then fall once it equilibrated with the temperature of the enclosure.  At
any rate the convections and mixing of the gases within the confinement
would be controlled by thermal gradients produced by changing temperatures
and pressure changes from external winds (breezes).  Kind of like baseboard
heaters and the movement of the surface of the toilet on a windy day.
 
        Just my perspective.  Mike
 
snip
 Now, if the
>bees are using up the available oxygen, leaving carbon dioxide, which will
>rise with the heat created, the hive becomes a death trap. The bees move
>upwards during the winter eventually ending up against the inner cover, into
>the strongest concentration of carbon dioxide. We know that oxygen breathers
>become sluggish due to oxygen starvation, which would account for the slow
>decline of some hives. Dr Nasr's work on Thermal Regulation states, "that
>bees use  more oxygen as the temperature drops", it could possibly account
>for a lot of winter kill.
>In the words of the CB'ers "Come on Back"
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