[Greenbuilding] FW: How green is cellulose infill? / thermal bridging?

[Alan Abrams]

 And two, to minimize 
thermal bridging. If the deeper wall were constructed simply of deeper 
studs (2x8, or 2x10 for example) you might have an R-24 or even R-35 
wall (cellulose is between R-3 and R-3.5, in my book), but it would have 
all these "stripes" where the studs are that would be more like R-8 or 
R-10. 

Hmmmm, anyone have any hard data on this issue of thermal bridging?  My
guess is that what is observed (in infrared photography, etc) is to a large
extent convection along the edge of fiberglass batts.  How much heat does a
2x6 actually conduct, particularly if it's snugly insulated, say, with
cellulose or sprayed in place polyurethane?  What is the moisture content of
wood members, when tested for thermal performance, compared to a stud that
lives in a thoroughly dried out wall cavity?  Is wood getting a bad rap,
thermally speaking?

Alan Abrams
Washington, DC