So, after I did Winterified! I wasn't going to stop there, so here are some autumn versions of the Miasmata and Granite Falls sets. The meshes you need are included, but go here and here if you want the full things.
These are just recolours of the trees and are not seasonal states. If anyone wants to make these trees seasonal using my recolours, please feel free.
Download here! Meshes included.