Cob: cob hybrids - alternatives for pressure treated wood

[Kerry S Tebbetts]

I've been reading the archives regarding cob hybrids.  I'm considering
all the options.  I'm trying to figure out a way to make my North, East
and West walls out of straw such as light clay or strawbale (although I
am very hesitant to use strawbale in my warm and humid climate).  Of all
the suggestions for cob hybrids, I like the cob house wrapped with
exterior strawbale the best (sorry, I can't remember whose idea it was to
give due credit).  However, as I've said, I'm leery of using strawbale. 
Also, I don't really think that any high mass material is necessary on
the North, east and west walls.  It would be pointless, it seems, except
to bear the load of the roof.  So, it would seem that a pole frame would
be a better solution, with light clay infill used where I want the
insulation and cob used where I want the mass.  

As I understand it, pressure treated lumber is recommended for a p&b, but
I really don't like the idea of using wood treated with arsenic. 
Besides, I have trees all over the place that are free.  Why go and buy
lumber that's been treated or have lumber treated if it's free?  Is there
a homemade recipe for treating wood?  Also, is there a way to use stones
for the pole footings rather than concrete?  My reasoning is that the
stone footings would keep moisture from being wicked up to the wood, the
same way that a cob's stone foundation does.   

I read a thread in the archives about the possibility of using cob to
form the posts for a post and beam frame?  Would this work?  Has anyone
tried it with any kind of success?

shae