Here are a few scenes after adding the crop of trees you saw on the plinths:









I've always thought modellers make them too dam small. A sixty-foot tree, especially in O Scale, is a large object. The goal here was not to make all of them huge, but a nice range of them but with a far larger average height than most folks do.

This really (counter-intuitively) lends itself to urban modelling. The spaces for trees are smaller and fewer, so larger more-detailed trees are "better". You aren't looking at forests, but individuals. BTW, except perhaps for the downtown concrete jungles, they are far more pervasive in the industrial and residential areas than modellers admit.

Anyway, that's the effect I'm after and the reasoning behind it all.