The columns on this unit are fluted, and the flutes stop before they reach the ends. That stopping is not decoration - it is what keeps the columns strong.
A flute is a groove, and a groove is a line of reduced section. Run flutes the whole length of a column and you have a series of parallel weak lines all terminating at the same point at each end, which is where a column will split if it is ever knocked. So our artisans stop the flutes short and leave a plain collar of full-thickness timber at the head and the foot, where the joints are.
The flutes themselves are set out by dividing the column's circumference into a whole odd number, so that a flute falls at the centre front and the arrangement is symmetrical from any angle a person is likely to stand.
At the top, each flute is stopped with a small carved bead rather than simply running out, which finishes the groove cleanly and stops it looking like a cut that was abandoned. It is a detail borrowed from stone columns, where the same problem was solved the same way a very long time ago.