Color is the starting point that I choose for my tree renderings. If you are ever to arrive at a coherent color scheme, you must resist making those trees green! Typically the local color of trees, green will key the color composition for you. If you wish green as a major element in your image, then use it. If not, then do a color study of your composition first to determine what color you will be making your trees.
The local color of trees is usually green, but if you think about it, there are other local colors of trees. Brown, orange, silver, gray and black are present. Trace or hints of red and blue are very evident to me in trees. Cast colors include violet and blue. When we view our trees in this manner, any color becomes part of the natural palette associated with trees.
Remember that color has much more value than associations with objects. Some assign emotional value to color, but I also think of it's plastic qualities. The red trees in this winter scene counter-pose the cool trend of a winter scene, and push them forward and cause vibration when compared to the ultramarine background.
Don't become a victim of the tyranny of green.