by Kathdys » Wed Dec 03, 2014 9:58 am
Heath and moor won't form within the tree radius (or at least won't stay) even if grass is planted within it. This is the radius outside of which grasslands will form without intervention. Once you're out of the woods, the process is random and takes time--you have to leave the plowed land until the 'plowedness' of it decays to some type of natural terrain. Planting grass on it prevents the terrain from decaying to a lower step, which prevents moor or heath tiles from appearing.
The usual place where heaths and moors will arise from grasslands are busy farms in deforested claims. Moors are still common on unmaintained farms, so converting moors to heath probably isn't that easy, either. I've seen many examples of farms where the terrain type has shifted one or more steps, but only one possible case of someone converting unclaimed terrain on purpose without leaving marks behind, and it might just have been that someone cut down all the trees standing between different natural terrain types.