There is little difference in the insulating value of the various
materials which may be obtained easily for the packing of hives in
winter. Exaggerated claims have been made by some beekeepers for such
materials as broken cork or certain commercial insulating materials,
but it is safe to say that there is not 25 per cent difference between
the poorest and the best of the available insulating materials,
provided, of course, that obviously poor things such as corn fodder
and straw be eliminated. Sawdust, fine planer shavings, forest leaves,
chaff, broken cork, and such materials may be used, the choice
depending chiefly on the availability of the materials. In general
it may be stated that the smaller and the more numerous the dead air
spaces confined in the packing, the greater will be its efficiency in
insulation. If forest leaves are used they must be gathered the year
before and stored, as the leaves fall some time after the bees should
be packed. If sawdust is used it is best not to pack it down tight, but
if forest leaves or planer shavings are employed it is essential that
they be packed in closely and that the containers be completely filled.
Broken cork, such as is used in the shipping of certain types of
grapes, is good and has the advantage that it does not hold moisture as
does sawdust. In all cases the packing should be placed in some sort of
box which will be rain-proof and thus protect the insulation from rains
and snow, for all insulating materials lose part of their efficiency
when wet.