Schilcote, by a timed tower farm, are you thinking along these lines? The inner fortress exports the season (by inner-fortress clock, I suppose, or just by the Z screen) to the outer fortress. The outer fortress, when the clock flag is recognized as properly triggered, say once every two years or however long it takes shrubs to grow into trees (caps), sends a signal back to the inner fortress to designate an area for tree-cutting. (If the game required additional muddying because tiles dry out (I don't think they do), the outer fortress could use the timer signal to open floodgates, etc.)
This is really incredibly clunky and complicated, of course. (Yay!) There's different levels of clunkiness: (i) you manually do all this inside a single fortress just by spotting that it's time to cut again (very easy and natural); (ii) you set up a clock etc. inside a single fortress timed to open a floodgate or somesuch; (iii) you run this process through an external dorfputer fortress, which is passed signals from the inner fortress, and basically behaves more like the first option, (i) above, such that the external fortress "recognizes" when it's time to do things, and, say designates an area for cutting.
The difference is that, in some meager sense, option (iii) is like artificial intelligence, trying to figure out how to run a game (a game which is separate from itself), whereas (ii) is "just" a game, where you stay in context, and imagine dwarves making machines to do things for them. In option (ii), the dwarves build a computer they use themselves; in option (iii), the dwarves build a computer which controls a game that you can imagine them looking at and laughing from outside. ("Mini-dwarves!")
I find this pretty interesting!