Looking at tree etc. and softening figured had to start even with softer species.
Would think matters less as pure column vertical against gravity of the long axis, but more concern bearing across either shorter axis, allowing long axis to be leveraged by load instead of supporting axis against loading.
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Also, wonder if would rot faster, and have less BTU value as wood, unless other absorbed stuff to affect (more here as a measure of wood density).
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Round definitively will be most equilateral even loading in winds etc. as a growing tree. Cornered/anything less than perfect round will impact weaker, lesser length axises more in shifting winds etc.
So I don't think is Naturally selectable/sustainable genetic, and nothing can teach or imbue as such, so always this special handling overhead of softening soft wood species even more and further 'crippling' form etc. Nature tends not to grow stuff squared, especially not evenly in growth.. And softer core from early stages may be maintained, in reverse of tree heartwood model. But, I guess we done same or worser to other things in other ways!.....
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Some industries now pay base salaries off of what once was wasted byproducts. Man tends to blindly watch maximize on product math, Nature tends to sometimes maximize on byproduct math, knowing product is already win!