because white is a dull colour its very blank it is not used in most drawings White is the lightest color and is achromatic (having no hue). its the opposite of black.so as barren lands are barren and the colour white is blank it is used to represent barren lands.
hope it helps i searched the answer as much as i could but i could not find an appropriate answer so i just thought of this
I seen someone yelling doing the chicken dance around the room they were looking at the camera with the chicken mask it was the funniest thing I ever seen