Just saw this entry on the Vault by Helvene: http://nwvault.ign.com/View.php?view=Hakpaks.Detail&id=7956 (Rural Winter Trees Override). It replaces the default BioWare rounded brown broadleaf trees with evergreens, and looks very nice (both in the toolset and in-game).
This entry gave me an idea, one which I do not have the time or skills to do myself. Why not make a non-overwriting copy of the [CEP] Rural tileset, but replace the trees in it with Helvene's (or similar) evergreen trees? Maybe call it "[CEP] Rural (Evergreen)" or something to set it apart.
After all, many northern climates have forests filled with evergreens. And winter is not the only season, even in northern places. Using the normal grass and colors would provide the ability to make such areas but with spring or summer in effect, rather than just frozen winter, and it would allow it to be done without resorting to dropping in dozens upon dozens of tree placeables.
