Exposure to light will affect the color of wood and the longer it is exposed the more the color can change. I am talking about unfinished wood.I have some pine,oak and walnut in a stack that has all aged to about the same color with a lot of sunlight hitting it through a window. Wood stack is about 40-50 years old.You have to scrape a piece to see what it actually is.Plane a piece of walnut and you can see that the surface color is often not very thick and leave the planed piece out and it will change color again.
