Termites or ???????????

[Xfaxman]

Look closer, the termites are only in the door frame, not the post. (I hope)

 

[Retiredguy2]

I put a new steel door on the back of my country house back in late 1988, then removed it in 2002 and replaced it with a wider one. Hung the older door on the north side of my garage back then and after 28 years of shaded use, last year the bottom part of the frame finally began rotting out. Your images appear a lot worse than what my old door looks like now.

 

[s219]

Yeah, I doubt the termites are into the treated column (now wood bees are another story -- they will bore into treated wood with no distinction).

Those door jambs are an easy target for rot and infestation. Typically they are made of a soft white wood and may as well be considered moisture/termite "bait".

I was interested to see that on our new house, all the Therma-Tru door jambs had the bottom 3-4" made of a composite material to avoid this common problem.