While your solution to eliminate the dark forest shadow between the forest edge and NML seems to make sense visually, in fact it does not. Generally these forests are supposed to continue across the 'mud', but of course they were blasted away. These forests appear on the large scale game map as such, so cropping their shape (getting rid of the shadow) is really not the best solution.
Well, I ran some tests tonight and it turns out not to be all that hard to edit the in-game map to more closely match up with the newly tweaked forest areas, so that should help eliminate problems of the map not matching what you see on the ground. Of course, that will add some time to the whole project, but I think it's probably worth doing so I'll add it to the project plan.
Man, I wish I had known how to do this stuff a few years ago, when there were still more folks around to be able to enjoy it. Oh well, better late than never I guess