Turning Archive 2005

Subject:
As the weird world turns

Carole in VA
>I thought I understood reaction wood on limbs of trees. I figured the weight of the limb (gravity) caused compression on the underside of the limbs resulting in a compressed pattern to the growth rings on the underside and a build up of support wood (reaction) on the top (tension) side relative to the pith. Then I started reading "Turning Green Wood" by Michael O'Donnell and found out my assumption was a little off base. Apparently it depends on which hemisphere you are in and whether it is hardwood or softwood! To quote:
"Hardwood trees in the northern hemisphere build reaction wood on the tension side of the pith, which gives rise to the growth rings in branches being wider on the tension side (the upper side) than the compression side. In the southern hemisphere, this is reversed: hardwoods build the reaction wood on the compression side of the pith (the underside of the branch). Softwood trees, on the other hand, produce reaction wood on the opposite side of the pith to hardwoods in both northern and southern hemispheres."
What? Is gravity upside down down there? And I wonder if, in the southern hemisphere, my little Spruce weather stick would flip-flop and curl down for dry weather and up for humid weather? LOL I am not even going to try and figure this out tonight, but I thought it was interesting.

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