You guys in America seem to struggle to find exceptable design values that you can really rely on except for the widely used timbers. The "Timber frame Joinery and design workbook" is has many places where it states that people just don't know.

I guess what I was asking was for a methodology of determining useful design criteria. It would have to be conservative but could it be done?

"The Wood Handbook" is a good place to start.

http://www.fpl.fs.fed.us/products/publications/several_pubs.php?grouping_id=100&header_id=p

Lots of good stuff there but I was really surprised that Pinus radiata does not seem to be listed. P. radiata is the most commonly propergated forestry tree in the world yet in the country where it comes from it doesn't rate a mention.

Check chapter 5, table 5 - 5a

Ha ha thats funny. It is in the imported woods table.

Not really so odd, pinus radiata natively exists in niches only in three groves in the US and is considered endangered. The plantation pinus radiata differs in growth and genetic characteristics from the native strain and would be considered invasive in the native stands. Furthermore all varieties would not likely be winter hardy in the northern and central tiers of states and Canada.

I knew it was endangered in its own range and that there would be good reasons for it not being propagated but it is still funny.

Small success. Modulus of rupture is six to times the fb rating. So to be safe fb=R/10.

Just need to find similar rules of thumb for Vertical and Horizontal shear.