Newman Atkinson says:

Simon I tried to right this earlier today and for somereason I bumped a wrong button and lost what I had wrote So here it is again: A good fall scene would have several kinds of trees that in their own timing they would drop their leaves at different times. Colors should follow the kind of trees you wish to have. Like higher elevation mountains like in Donnor Pass of California would have big fir trees and pines with mixed in aspen trees which are not as tall. In the fall these leaves would have a general yellow as they turn and if there is an early winter storm these trees would not have dropped their leaves yet nd could have drooping limbs with the yellow leave hanging on the, They would be mixed in with the fir or pines especially along the rail right away. Also it would be an interesting thing like here in the US the Western slopes of Donnor Pass is National park land and like modern cell towers, nothing can be put in a National park unless it matches the terrain. On the southern lower forested slope they installed cell tower but it was made to look like a large fur tree. The only thing that gave it away was was the antennas were green fur branches that were vertical The rest of the tree was a made to look like regular fur branches but made of metal. If you did not know much about these many people would have let it pass as a real tree. Was we passed it from Amtraks lounge sightseer lounge car we were able to get a photo of it. Other trees such as the red maple leaves and the yellow for yellow leaves would be somewhat bare with the leafs on the ground spreading on the ground below them as if the winds had blown them away from the tree trunk. Aspens as I mentioned before will grow in small groves in the woulds spiratically in between fur tree groups or pine tree groups. And along the tracks would be a sprinkle to break the green fur or pine trees. Oak Trees leaves will generally turn brown and many will fight tooth and nail against the winter winds to keep from dropping to the ground. Bush finer branches can be put together and make lighter trees such as the aspens. You will need some trees with all the leaves gone from the trees depending on how late of a fall look you would want. It is kind of like field corn plants when they are ready to pick the plans and ears usually are still standing tall. but as your season progresses to the cold and should have already been picked the corn plants will be with the leaves drooping and the corn ears hanging like they want to drop. I hope I have helped you with some ideas for your mountain scenes from Newman