This is a known issue but I thought I would submit a formal bug report supported with a screenshot and actual location evidence. The RSN route appears to be the only one where winter conditions are properly simulated by the Speedtree models. I have heard a rumour it something to do with the fictional temperature, perhaps suggesting Germany is set in the game to be the only area that gets cold enough for the leaves to fall. Clearly that's not the case and either way it makes no sense as the Service Mode set up screen tells you the simulated temperature, and Transpennine is just as cold as RSN. So in this example I selected to spawn on foot in service mode on the TransPennine route. My environment pre-selects were: Winter Clear 11.50am Deighton Station The stated temperature was 13.1 degrees. You can see from the screen shot that the trees look like they would in late summer / early autumn. They look like they are all deciduous trees to me so they should be displayed as bare trunk and branch.