This. You buy a 4"x4" post (nominal. Actually 3.5"x3.5") at your local home improvement store and it has wane on all four corners and the pith running down the middle.
Translation: it's made from the smallest possible tree you could plausibly saw a 4x4 out of. And the pith (the center of the trunk) running through the middle guarantees that the post will split along the radial plane as it dries.
If you go to a better lumber yard, you get better lumber. Except, apparently, for 2x3's. They are universally crap. Source: built a chicken coop with 2x3's and bought from a local outfit because they deliver inexpensively. Everything else was gorgeous compared to the box home improvement store. The 2x3's were pretty much the same.
Heard you should get the largest lumber you can get and rip it down. Like get 2 x 12's and rip down to 2 x 4's.
Makes sense that the larger cross-sectional lumber needs to come from a larger cross-sectional tree with few defects. The crap-wood they can turn into 2x4, 2x3....
I did the above to create a nice workbench with few knots. It helped of course that the lumber I ripped was glued up to make the butcher-block-style top, the uprights and cross braces also doubled, tripled up.
Translation: it's made from the smallest possible tree you could plausibly saw a 4x4 out of. And the pith (the center of the trunk) running through the middle guarantees that the post will split along the radial plane as it dries.
If you go to a better lumber yard, you get better lumber. Except, apparently, for 2x3's. They are universally crap. Source: built a chicken coop with 2x3's and bought from a local outfit because they deliver inexpensively. Everything else was gorgeous compared to the box home improvement store. The 2x3's were pretty much the same.