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RE: Douglas Fir Larch Strength

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Jie -
  I don't have these documents in front of me but I suspect that the bending
stress adjustment is in recognition of the continuing reduction of "old
growth" tree availability and the increasing use of "younger" timber. I use
Hem-fir No. 2 for my timber projects and have also noticed the allowable
stress adjustments.

> ----------
> From: 	Jie Lu[SMTP:jie(--nospam--at)ibrahim.biz1.net]
> Reply To: 	seaint(--nospam--at)seaint.org
> Sent: 	Tuesday, September 15, 1998 8:16 AM
> To: 	seaint(--nospam--at)seaint.org
> Subject: 	Douglas Fir Larch Strength 
> 
> Is there someone can help to explain the following question?
>  
> The "fb" for Douglas Fir Larch No. 2 is 1250 psi for single memebr based
> on WWPA's 1988 Manual  "STANDARD GRADING RULES FOR WESTERN LUMBER".
>  
> However, the NDS Supplement 1991's Table indicates the "fb" value is only
> at 875 psi (see page 20). 
>  
> Thanks.
>  
> J. L.
>