The closet rods I have around are coated but that's a good point about the kind of wood. I wouldn't worry too much about pine but it's not very strong
compared to other kinds of wood, I didn't think they used pine for closet rods? I can't tell from the wood grain what mine are but some sort of hard wood
I'd have to assume.
https://en.wikipedia.org/wiki/List_of_woods
Another thing you could use for "branches" are bamboo poles...a local feed store has them, 6' long & economical. Just not as big around...