I'm very confused now. As I've been working on the first set of three bridges, lowering the structure and road bed adjustment, I've run the mask two more times. Now all river widths wider than 50, the trees are being removed. Since I discovered the issue, that is four runs of the mask for it to work properly.
Another issue that may be with roads and micro hills they run over in DX11, I will have to keep testing and see if it happens in DX9. Since all the road paths are now in, when I spawn in to an area with a path within 1 mile of the spawn area. In the first maybe 500yds of travel of my vehicle, there are numerous micro stutters, then they stop after traveling past about 500yds. This did not happen before laying down the roads with only the rivers in place.
After I adjust all the bridges I will test for this phenomenon in DX9 and DX11.