Joni Mitchell is an undoubtedly prolific songwriter, but she may be equally renowned for her use of alternate tunings when composing classics such as "Little Green" (in open G) off her seminal album Blue.
Read more about Joni Mitchell's open tunings: https://goo.gl/VRNuet
Shop Joni Mitchell albums on Reverb LP: https://goo.gl/xyqj7y