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Thread: Causal factor for Twisted Lumber

  1. #1 Causal factor for Twisted Lumber 
    Forum Radioactive Isotope sculptor's Avatar
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    I have noticed that most(well over 90%) of the twisted lumber I see twists the same way.
    (I recently stacked about 200 14' and 16' long 2x4s and 2x6s, and of the 50 or so that were twisted, only one twisted the opposite way--and that one had a lot more grain runout than normal)

    As I look down the length of a 2x4, it will twist anti-clockwise as it goes away from me, or conversely, seem to twist clockwise as it comes toward the viewer.

    Northen hemisphere cyclones (low pressure domes) twist anticlockwise as you look down on them.
    Southern hemisphere cyclones (low pressure domes) twist clockwise as you look down on them.
    While winds around high pressure domes move clockwise.

    so looking "down" on the 2x4 that came from a northern hemisphere forest, it seems to mimic the pressure pockets of our hemisphere.

    ---------------
    coincidence? or causality?
    ..........
    So, the question obtains:
    Does timber harvested from southern hemisphere forests tend to twist in the opposite direction of northern hemispher's lumber mimicing or caused by the same mechanism governing cyclones and pressure domes?

    Any of you southern hemisphere guys notice the twist in lumber from your hemisphere?
    and which way does it twist?


    Last edited by sculptor; September 6th, 2012 at 08:59 AM.
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  3. #2  
    Time Lord Paleoichneum's Avatar
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    The twist is going to be due to the twist of the tree its self. That twist is generated by sustained winds over the lifetime of the tree that originate from one direction. Thus a tree in a mountain valley which gets hit with a constant wind blowing down from the pass will develop a twist based on whatever side of the tree catches more wind more often. See here for a little better explanation: Krummholz - Wikipedia, the free encyclopedia


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  4. #3  
    Comet Dust Collector Moderator
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    Another factor mightbe the movement of the sun. Plants try and follow the sun (phototaxis) so in the northern hemisphere try and face east in the morning and twist toward the west along the southern sky during the daylight hours.
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  5. #4  
    Forum Radioactive Isotope sculptor's Avatar
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    thanks Paleo and wayne
    I have considered both of these
    I carved part of a wind twisted tree once-------what a trip--following the grain was an exercise in ambidexterity. My one piece of the log made a nice sculpture, and an interesting walking cane.
    ............

    My guess is that the mentioned 2x4s and 2x6s were from tree farm trees. They had reasonably straight grain, and most likely were not milled twisted, however the stresses in the lumber led to the twisting, just as stresses lead to cupping and bowing .............especially in the oaks, the rings seem to want to straighten out which leads to cupping, so on my wide plank floors, I try to place the pith side up, ...

    the question remains:
    what stresses would lead to almost all the lumber choosing to twist in the same direction
    if it were phototaxis or wind generated krummholz, I'd expect to see a balance of twisting clockwise and counterclockwise
    but that is not the case.
    ergo my question about twist in lumber from trees in the southern hemisphere-------if the twist were opposite, it would be a good lead, and if the same, then that would eliminate one course of investigation--------
    -----
    incidentally, (re)seasoning th lumber in stickered stacks with weight on top removes most of the twist.
    but doesn't satisfy my curiousity
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