There was once a graphics mod around that made forests continue to grow over improvements, as they did prior to some version (0.33, I think). I had forgotten I had it installed until I started my first game as the Ljosalfar in 0.40. The disappearing Ancient Forests are really annoying; anyone have a link to the graphics mod for the old version (or just a quick fix I can do myself, which I suspect is what it is).