Blue Sap?

Larry Caldwell larryc at
Mon Jan 26 14:08:19 EST 1998

In article <19980126055501.AAA25264 at>,
randyfulle at (RandyFulle) wrote:

> Sorry Larry, blue stain does not attack wood. It plugs-off water transport.

OK, if you say so.  I was just going by the sap color entry in my copy of
"Supplement to Official Log Scaling and Grading Rules."

"The term 'sap color' refers to any color in the sap area not normal for that
species of log.  These generally will show in end views or in probings as 
various tints of blue, brown, or red.  Such abnormal colorings usually
indicate early stages of an attacking rot and must be carefully checked
for soundness."

I know little boring beetles leave blue trails because of a fungus they
carry around on their feet.  I think that's the one that blocks off
water transport in the cambium?  There is also a blue stain that attacks
the sapwood, particularly in pine.  I don't know that the two fungi are
the same.

-- Larry

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