Built as here described, the cold wind might come through in the
winter-time, but if you can gather a lot of Sphagnum moss from the nearest
swamp and cover your roof with it and then shingle that over with another
layer of birch bark, the cold wind will not come through your roof. If you
treat your side walls in the same manner and heap dirt up around the edges
of them, you will have a comfortable winter camp.
In the winter-time you will find it very difficult to peel the birch bark
or any other kind of bark, but when the sap is flowing it is not so
difficult to secure bark slabs from many varieties of trees.