I would suggest starting out with the trees that are included in the version of Trainz you're using and searching online to find out the area where a species of tree lives. Also, once you get the necessary info, I'd suggest writing on a piece of paper a list of the trees needed for that route; but just using your computer's writing program (i.e. Microsoft Word) to do the same thing. Doing this is easier than just memorizing it in your head. Also, if you took a college science class called 'Environmental Studies' (which was the ONLY class that involved a lab where you don't dissect an animal), you can just E-Mail your teacher a list of the trees you have installed on your edition of Trainz, where the route you're using the trees is located, and any other information about your route. He might send a reply with a document attached listing the appropriate trees for that route.
