A length of sticks, lashed, usually on an inside wall, but in this illustration, hanging outside. They don't look at them, or talk about them, or touch them, in any of the shows I've seen, but the set dressers keep putting them in there. I've seen them in three or four or more of the "sangeuk" (historical dramas)—set in the Joseon period, 16th-18th centuries, mostly. They've been in poor rooms, and nicer ones (though not in palaces or offices, that I've seen).
My best (wild, foreign) guesses are that it's a calendar (remove a stick each day?), or fire-starting wood that will be dry because it's inside (or resin-rich fatwood, maybe).