Akira, I like this photo, and the following discussion about colour is interesting. In my own photos I often have difficulty rendering greens accurately (or in a way that is faithful to my recollection of the scene). I have a tendency to "edit in" overly-yellow shades, which look wrong when I view the photo later. I occasionally wonder if I have some mild form of red-green colour-blindness, which I believe is quite common in males. Anyway, your image contains at least 5 distinct shades of green, which appear nicely and properly rendered on my screen!
Cheers, John