>Cold DRY air helps,  but moist wet air  like we have here in mid southern
IL is a nightmare.   You wrap a hive here without a upper entrance and you
will have a dead wet moldy mess in spring.

In Atlantic Canada we have a maritime climate (cold, very moist, very
windy, and enought snow some years to completely bury the hives (2 metres
over the covers two winters ago).  You could not think of overwintering
without a top entrance.  Without the hot air exiting the upper entrance the
hives would suffocate.   When we have a winter where the hives are buried
deep under snow there is a lot of faeces around the entrance, but survival
can still be good as long as the snow doesn't get an icy crust.  A big cave
forms around the hives with lots of surface area for air exchange.



> I did use upper entrances in IA,  smaller than I use here,  but still
> present.  This allowed a small amount of "chimney" effect in the hive,  and
> you could normally see cold air  frost around the upper openings.  Here in
> IL I use a 3/4 X 4  upper and a 2" lower opening.
>

My top entrance is just 3/4 x 3/4.  When we wrap we have to open some that
the bees have filled with propolis.


> For several years I used some BeeMax  foam hives.   Didn't notice any help
> with them until I punched a 3/4 hole just below the top. Of the box.  This
> lets a bit of air exchange, and wintering success went up dramatically in
> the foam hives from that little tweak.
>

It is interesting to note that in Scandinavia they have said in previous
discussions on this list that they use only bottom entrance with foam
hives.  I think they have lots of snow there too, so I would be interested
to know how the bees cope with that.

Stan

             ***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software.  For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html