Hi Bill

 > Why close off top ventilation? Or is this just part of the continuing
 > argument over top ventilation in winter? If so, I understand but is it
 > connected to the OA treatment?

It is a wintering thing, not the treatment... There are many arguments 
about whether or not top ventilation is beneficial, many of these 
arguments are based on over simplified physics, to be really successful 
in very cold and harsh winters requires no ventilation at the hive top 
and a considerable layer of insulation material within the hive cover.

However, for this to work it relies on the bees being attuned to the 
conditions encountered, such that they actually shut down for winter. If 
you use a bee that is inappropriate for the cold region, you are likely 
to end up with a population that is too numerous for this shut down to 
occur and the larger population will remain quite active, consuming 
large quantities of stores and making the moisture problem worse, to 
such an extent that top ventilation has to be brought into the equation 
to compensate.

So it not a case of whether top ventilation or no ventilation is 'right' 
it depends on whether the bee is right for the conditions. If the bees 
are not 'right' you have to make the best of a bad job and use top 
ventilation and the high amount of winter stores that need to be fed to 
keep the over active bees alive.


Regards & Best 73s, Dave Cushman, G8MZY
http://website.lineone.net/~dave.cushman or http://www.dave-cushman.net
Short FallBack M/c, Build 6.02/3.1 (stable)

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