From this angle, which is the operator's point of view, the reason for the line of trees becomes clear; it prevents you seeing the tracks behind them and so helps retain the model's illusion of distance.

indentYou will have noticed many signals on Tupdale; original Midland bracket signals, tall ex-Midland ones with LMS replacement arms and standard LMS round-post ones.  Here is an early LMS lattice-based bracket signal which they used before adopting the more familiar round post type.  It is very similar to one at Appleby (by the goods shed).
indentIt is by noticing such subtleties and reproducing them that one can create an imaginary layout with all the "feel" of a genuine Settle and Carlisle station.  Well that's my opinion - what's yours?