yeah, whether green or brown, colours are our personal preferences and prolly developed over time. Your post reminded me of how I was accustomed to perceive mountains as brown structures (as I grew up seeing those old Aravali ranges in Rajasthan) that we always used to draw & colour all mountains as brown in our school drawing classes. But when I moved in dense forests of hilly Assam, it was green all over. This actually made me ask my parents whether mountains can be green too. It really took me a lot of time to perceive those hills as real mountains and to draw & colour them as green, lol!.