Liriodendron tulipifera, aka tuliptree, aka tulip poplar produces wood that is sold commercially as “poplar”. It’s actually not related to true poplars at all. It’s usually the cheapest readily available hardwood (at least in the US). Its wood is definitely softer than oak, or any of the other common hardwoods used in woodworking. It’s also a strange mix of green, white, and some purple, which sounds cool, but usually doesn’t look good, so it’s usually painted.