Re: Botany: Just a question regarding the properties of birch bark.

I don't have an exact answer, but there are some clues which may contain the
answer.  Birch bark was used by Native Americans and early settlers for many
purposes probably due to the numerous organic molecules found  therein.  The
first thing many people think of is birch bark canoes or shingles, or even
clothing.  Apparently birch bark is impervious to water, and it also is easily
removed from the trees.  The main organic constituents of the bark (betulin or
beta camphor, betuloresinic acid; both are steroid-like molecules) are nearly
insoluble in water, which might help keep the bark  dry for burning or keeping
the canoe afloat.  One source said that even when it is raining, you can start a
fire with birch bark.  But these molecules are not very combustible.  Other
organic molecules are found in much smaller quantities, but are flammable--cresol,
phenol, xylenol, guaiacol).  The combination of these two sets of components might
be responsible for birch bark's burning properties.