I didn't realize it, but upon closer inspection, nose to the floor with my glasses off, there is definitely a difference between the two types of wood. One is clearly oak, but the other isn't.... I've attached a few more pics, the oak pieces are diagonal, whereas the unknown ones are straight. I don't know enough to make an educated guess, and I'd think a few trips to a big box store would leave me even more confused. Maple? Birch?